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1

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

NASA Technical Reports Server (NTRS)

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.

Arcidiancono, Antonio

1990-01-01

2

Satellite-Based Quantum Communications  

SciTech Connect

Single-photon quantum communications (QC) offers the attractive feature of 'future proof', forward security rooted in the laws of quantum physics. Ground based quantum key distribution (QKD) experiments in optical fiber have attained transmission ranges in excess of 200km, but for larger distances we proposed a methodology for satellite-based QC. Over the past decade we have devised solutions to the technical challenges to satellite-to-ground QC, and we now have a clear concept for how space-based QC could be performed and potentially utilized within a trusted QKD network architecture. Functioning as a trusted QKD node, a QC satellite ('QC-sat') could deliver secret keys to the key stores of ground-based trusted QKD network nodes, to each of which multiple users are connected by optical fiber or free-space QC. A QC-sat could thereby extend quantum-secured connectivity to geographically disjoint domains, separated by continental or inter-continental distances. In this paper we describe our system concept that makes QC feasible with low-earth orbit (LEO) QC-sats (200-km-2,000-km altitude orbits), and the results of link modeling of expected performance. Using the architecture that we have developed, LEO satellite-to-ground QKD will be feasible with secret bit yields of several hundred 256-bit AES keys per contact. With multiple ground sites separated by {approx} 100km, mitigation of cloudiness over any single ground site would be possible, potentially allowing multiple contact opportunities each day. The essential next step is an experimental QC-sat. A number of LEO-platforms would be suitable, ranging from a dedicated, three-axis stabilized small satellite, to a secondary experiment on an imaging satellite. to the ISS. With one or more QC-sats, low-latency quantum-secured communications could then be provided to ground-based users on a global scale. Air-to-ground QC would also be possible.

Hughes, Richard J [Los Alamos National Laboratory; Nordholt, Jane E [Los Alamos National Laboratory; Mc Cabe, Kevin P [Los Alamos National Laboratory; Newell, Raymond T [Los Alamos National Laboratory; Pterson, Charles G [Los Alamos National Laboratory

2010-09-20

3

Satellite-based quantum communications  

NASA Astrophysics Data System (ADS)

Single-photon quantum communications offers the attractive feature of ``future proof'' security rooted in the laws of quantum physics for the transfer of cryptographic keys. Secure distribution of keys is necessary for the encryption and authentication of conventional communications. Ground-based quantum communications experiments in optical fiber have attained transmission ranges in excess of 200km, but for larger distances to become feasible we proposed a methodology that would make satellite-to-ground quantum communications possible. Satellite feasibility studies have been published by research groups in the US, Europe, Japan and China, and collaborations in several countries have published conceptual experimental plans. In this talk we will review the main features required for low-earth orbit satellite-toground quantum communications, and describe the results of ground-based quantum communications experiments across atmospheric paths conducted by our team over the past decade. Using these results as an anchor, we will describe a link model, incorporating photon transmission, loss and background physical processes, for estimating satellite-to-ground quantum communications performance. We will show results from this model for the projected performance of a hypothetical quantum communications terminal on the International Space Station, with a hypothetical ground terminal in Los Alamos, NM.

Hughes, Richard

2011-06-01

4

Satellite-Based Education. A Preliminary Review of the Feasibility of Satellite-Based Educational Communications Technology.  

ERIC Educational Resources Information Center

The findings of an investigation by the Educational Committee of the New York State Senate on the advantages of satellite-based educational communications technology are summarized. After a brief foreword by the Chairman, the report is divided into three sections: suggestions for utilizing the technology of satellite-based communications; the need…

New York State Senate, Albany. Senate Education Committee.

5

Trellis-coded CPM for satellite-based mobile communications  

NASA Technical Reports Server (NTRS)

Digital transmission for satellite-based land mobile communications is discussed. To satisfy the power and bandwidth limitations imposed on such systems, a combination of trellis coding and continuous-phase modulated signals are considered. Some schemes based on this idea are presented, and their performance is analyzed by computer simulation. The results obtained show that a scheme based on directional detection and Viterbi decoding appears promising for practical applications.

Abrishamkar, Farrokh; Biglieri, Ezio

1988-01-01

6

Trellis-Coded CPM (Continuous-Phase Modulated Signals) for Satellite-Based Mobile Communications.  

National Technical Information Service (NTIS)

Digital transmission for satellite-based land mobile communications is discussed. To satisfy the power and bandwidth limitations imposed on such systems, a combination of trellis coding and continuous-phase modulated signals are considered. Some schemes b...

F. Abrishamkar E. Biglieri

1988-01-01

7

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

NASA Technical Reports Server (NTRS)

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.

1989-01-01

8

Air traffic management system design using satellite based geo-positioning and communications assets  

NASA Technical Reports Server (NTRS)

The current FAA and ICAO FANS vision of Air Traffic Management will transition the functions of Communications, Navigation, and Surveillance to satellite based assets in the 21st century. Fundamental to widespread acceptance of this vision is a geo-positioning system that can provide worldwide access with best case differential GPS performance, but without the associated problems. A robust communications capability linking-up aircraft and towers to meet the voice and data requirements is also essential. The current GPS constellation does not provide continuous global coverage with a sufficient number of satellites to meet the precision landing requirements as set by the world community. Periodic loss of the minimum number of satellites in view creates an integrity problem, which prevents GPS from becoming the primary system for navigation. Furthermore, there is reluctance on the part of many countries to depend on assets like GPS and GLONASS which are controlled by military communities. This paper addresses these concerns and provides a system solving the key issues associated with navigation, automatic dependent surveillance, and flexible communications. It contains an independent GPS-like navigation system with 27 satellites providing global coverage with a minimum of six in view at all times. Robust communications is provided by a network of TDMA/FDMA communications payloads contained on these satellites. This network can support simultaneous communications for up to 30,000 links, nearly enough to simultaneously support three times the current global fleet of jumbo air passenger aircraft. All of the required hardware is directly traceable to existing designs.

Horkin, Phil

1995-01-01

9

Radio communications with extra-terrestrial civilizations  

NASA Technical Reports Server (NTRS)

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.

Kotelnikov, V. A.

1974-01-01

10

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

NASA Astrophysics Data System (ADS)

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 quantum communication applications such as quantum cryptography on a global scale. Integration of a source generating entangled photon pairs and single-photon detection into existing optical terminal designs is feasible. Even more, major subunits of the classical terminals such as those for pointing, acquisition, and tracking as well as those providing the required electronic, thermal, and structural backbone can be adapted so as to meet the quantum communication terminal needs.

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

2005-09-01

11

A Analysis of Noise and Interference in a Satellite Based Mobile Communications System  

Microsoft Academic Search

In any satellite-to-mobile or mobile-to-mobile communications system, the effects of fading, propagation path loss, noise, interference, and non-linearities on the signal have to be considered. The basic problem is to evaluate the performance of such a communications link for various signaling schemes. However, the multitude of the noise, attenuation and interference effects described above would introduce so many variables that

Shalom Solomon Bergstein

1983-01-01

12

An analysis of noise and interference in a satellite based mobile communications system  

Microsoft Academic Search

In any satellite-to-mobile or mobile-to-mobile communications system, the effects of fading, propagation path loss, noise, interference, and non-linearities on the signal have to be considered. The basic problem is to evaluate the performance of such a communications link for various signaling schemes. However, the multitude of the noise, attenuation and interference effects described above would introduce so many variables that

S. S. Bergstein

1983-01-01

13

Application of a satellite-based terrestrial carbon flux model for quantifying recent climate and fire disturbance impacts on northern ecosystem productivity  

NASA Astrophysics Data System (ADS)

Quantifying variability and underlying environmental constraints on carbon (CO2) sequestration in northern (? 45 °N) ecosystems is important for improving predictions of future climate change. We applied a satellite-based terrestrial carbon flux model for daily estimation of net ecosystem CO2 exchange (NEE) and component carbon fluxes across a pan-boreal/Arctic domain. The model includes a light use efficiency algorithm for estimating vegetation gross primary production (GPP) using operational satellite NDVI records, while ecosystem respiration is derived using a three-pool soil decomposition model adapted to utilize potential inputs from satellite microwave retrieved soil moisture and temperature as primary environmental constraints to soil respiration. Initial validation against tower eddy-covariance measurement based carbon fluxes for northern tower sites showed favorable results for GPP (R ? 0.7, RMSE < 2.5 g C/m2/day), and overall consistency for NEE (R > 0.5) at predominantly undisturbed sites. However, the terrestrial carbon uptake during the peak growing season was generally underestimated by the model especially for deciduous broadleaf forests, mainly due to under prediction of GPP over dense canopy areas and model steady-state assumptions of dynamic equilibrium between vegetation productivity and respiration processes. A model framework integrating satellite-based burned area products and vegetation indices was then developed to represent non-steady-state fire disturbance and recovery effects and the simulations largely tracked NEE recovery indicated by tower CO2 flux measurements over three boreal fire chronosequence networks. The regional simulations indicated that large drought and fire events were generally associated with large GPP reductions and net ecosystem carbon losses, though NEE was generally less sensitive to fire disturbance due to similar behavior in GPP and respiration components. These results are being used to inform development of an operational carbon product for the NASA Soil Moisture Active Passive (SMAP) mission.

Yi, Y.; Kimball, J. S.; Jones, L. A.; Reichle, R. H.; Nemani, R. R.

2012-12-01

14

A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

15

A satellite based telemetry link for a UAV application  

NASA Technical Reports Server (NTRS)

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.

Bloise, Anthony

1995-01-01

16

Power and Bandwidth Effective Data Communications in Disaster Relief Operations through a Satellite-Based Disruption Tolerant Network Paradigm  

Microsoft Academic Search

Providing effective telecommunication infrastructures for disaster relief and emergency operations can be achieved by taking advantage of anywhere-anytime communication capabilities offered by satellite and wireless technology. In this perspective, designing a network architecture able to ensure reliable and timely delivery of data, and able to resist against link disruption is of utmost importance. To this end, this work proposes a

Tomaso De Cola; Mario Marchese; Annamaria Raviola

2008-01-01

17

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

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

18

Refinement of rooting depths using satellite-based evapotranspiration seasonality for ecosystem modeling in California  

Microsoft Academic Search

Accurate determination of rooting depths in terrestrial biosphere models is important for simulating terrestrial water and carbon cycles. In this study, we developed a method for optimizing rooting depth using satellite-based evapotranspiration (ET) seasonality and an ecosystem model by minimizing the differences between satellite-based and simulated ET. We then analyzed the impacts of rooting depth optimization on the simulated ET

Kazuhito Ichii; Weile Wang; Hirofumi Hashimoto; Feihua Yang; Petr Votava; Andrew R. Michaelis; Ramakrishna R. Nemani

2009-01-01

19

Rural Communications Planning Methodology for Integrating Satellite and Terrestrial Facilities.  

National Technical Information Service (NTIS)

A computer program is described which optimizes the design of rural telephone networks by choosing the best combination of cable, open wire, VHF radio, communications satellite stations, and placement of local exchanges. Each service area is described for...

R. G. Sharma

1976-01-01

20

The "Ethical Paradox of Communication with Extra-Terrestrial Intelligences"  

NASA Astrophysics Data System (ADS)

Technological conditions required by the boundaries of our human intelligence to communicate with E.T. intelligence could put us within a situation in which one could abdicate a fundamental part of what it means to be human.

Lestel, D.

2010-04-01

21

Wireless infrared communications for space and terrestrial applications  

NASA Technical Reports Server (NTRS)

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.

Crimmins, James W.

1993-01-01

22

Performance Comparison of BB84 and B92 Satellite-Based Free Space Quantum Optical Communication Systems in the Presence of Channel Effects  

NASA Astrophysics Data System (ADS)

The performance of single photon pulsed polarization based BB84 and B92 platforms against individual attacks for free space quantum optical communication links between a ground station and a satellite in the low earth orbit is compared. The comparison is attained by evaluating the quantum bit error rate and secure communication bit rate on secure optical link loss and the sensitivity of different parameters. Precisely, realistic experimental parameters are used and the obtained results are compared with those of other papers. Quantum bit error rates as low as 3.5% have been regularly obtained. Moreover, with repetition rate of 10MHz at the low earth orbit standard orbital altitude of 100 km and at zenith angle of 60 degrees, secure communication bit rates of ~ 280 kHz and ~ 70 kHz were received for the BB84 and B92, respectively. The obtained results show that the BB84 protocol exhibits better performance than B92 in the distribution of the secure communication key over long distance. Overall, these results reveal that it is possible to obtain secure key exchange in the low earth orbit, an idea which can be extended to other long distance laser links such as geostationary orbit.

Etengu, R.; Abbou, F. M.; Wong, H. Y.; Abid, A.; Nortiza, N.; Setharaman, A.

2011-04-01

23

A Real-Time Testbed for Satellite and Terrestrial Communications Experimentation and Development  

NASA Technical Reports Server (NTRS)

This paper describes a programmable DSP-based testbed that is employed in the development and evaluation of blind demodulation algorithms to be used in wireless satellite or terrestrial communications systems. The testbed employs a graphical user interface (GUI) to provide independent, real-time control of modulator, channel and demodulator parameters and also affords realtime observation of various diagnostic signals such as carrier, timing recovery and decoder metrics. This interactive flexibility enables an operator to tailor the testbed parameters and environment to investigate the performance of any arbitrary communications system and channel model. Furthermore, a variety of digital and analog interfaces allow the testbed to be used either as a stand-alone digital modulator or receiver, thereby extending its experimental utility from the laboratory to the field.

Angkasa, K.; Hamkins, J.; Jao, J.; Lay, N.; Satorius, E.; Zevallos, A.

1997-01-01

24

14 CFR 141.91 - Satellite bases.  

Code of Federal Regulations, 2010 CFR

...2014-01-01 2014-01-01 false Satellite bases. 141.91 Section 141.91...SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a pilot...chief instructor is designated for each satellite base, and that assistant chief...

2014-01-01

25

Design of terrestrial/satellite computer communication networks using slotted Aloha and SS/TDMA satellite systems  

NASA Astrophysics Data System (ADS)

With the rate of growth of packet-switched computer communication networks, the future networks are expected to comprise hundreds or thousands of packet switching nodes. In view of the network design and computational time requirements, ultimately the topological design complexity of such large-scale computer communication networks would grow exponentially with the size of the network. Therefore, efficient procedures for the design and operation of large-scale computer communication networks are required. In this paper, a multilevel hierarchical approach is presented for the topological design of a large-scale computer communication network using terrestrial and Slotted Aloha and satellite Switched SS/TDMA satellite with terrestrial or mixed-media systems. In this paper, for a given set of packet switching nodal locations, the nodes are initially decomposed into an M-level Hierarchical Clustering (MHC) structure. Then, an M-level Hierarchical Topological (MHT) structure is formed over the above MHC structure. Finally, an M-level Hierarchical Routing (MHR) scheme is presented for routing the messages between any source-destination node-pair. Also, an expression for the average time delay of a message in an M-level hierarchically clustered and topologically structured terrestrial and satellite computer communication network is given.

Ramaswamy, Raju

1990-03-01

26

Satellite-based laser windsounder  

SciTech Connect

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.

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

1997-08-01

27

A secure and efficient satellite-based multicast architecture  

Microsoft Academic Search

Low earth orbit satellite-based multicasting technologies are well-suited for secure group communications in a widely distributed, highly mobile environment. We present a novel modular multicasting architecture designed to increase system scalability for secure operations in a low earth orbiting satellite system. Simulation results demonstrate superior per-user average re-keying performance over baseline and clusterized architectures in various modeled scenarios. In scenarios

Victor Hubenko; Richard Raines; Rusty Baldwin; Barry Mullins; Robert Mills; Michael Grimaila

2008-01-01

28

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)

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.

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

29

Effects of the upper atmosphere on terrestrial and space communications: the new cost 271 action of the European scientific community  

NASA Astrophysics Data System (ADS)

During the last decade important results have been obtained by the two COST Actions (Co-operation in the Field of Scientific and Technical Research) promoted by the European Union: the PRIME (Prediction and Retrospective Ionospheric Modelling over Europe) and the IITS (Improved Quality of Service in Ionospheric Telecommunication Systems Planning and Operation). The European scientific community involved in the ionospheric physics, radio propagation and space science has then proposed a new 4 years Action on the effects of the upper atmosphere on terrestrial and Earth space communications. The objectives and the most important directions of this recently accepted COST271 project are here shortly outlined.

Zolesi, B.; Cander, Lj. R.

30

Effects of the upper atmosphere on terrestrial and Earth space communications: Final results of the EU COST 271 Action  

NASA Astrophysics Data System (ADS)

Project “Effects of the Upper Atmosphere on Terrestrial and Earth Space Communications (EACOSs)” was inaugurated as a four-year 271 Action in the Telecommunications and Information Science and Technology domain of the EU COST (Co-operation in the Field of Scientific and Technical Research) in October 2000. It followed two previous successful Actions COST 238 on PRIME (Prediction and Retrospective Ionospheric Modelling over Europe) and COST 251 on IITS (Improved Quality of Service in Ionospheric Telecommunication Systems Planning and Operation). The COST 271 Action (EACOS) has been oriented towards: (i) collection of new ionospheric and plasmaspheric data for now-casting and forecasting purposes, (ii) development of methods and algorithms to predict and to minimise the effects of plasmaspheric ionospheric perturbations and variations on communications; (iii) perform studies that influence the technical development and the implementation of new communication services, particularly for the GNSS and other advanced Earth space and satellite-to-satellite applications; and (iv) dissemination and correlation of results, ideas and information which will provide a valuable support to European research centres and industry. This paper reviews the main results achieved in the COST 271 Action concerning in particular a range of the ionospheric space weather issues, specifically: now-casting, forecasting and warning tools, methods and supporting databases for ionospheric propagation prediction; total electron content variations and their use in the reconstruction of plasmaspheric ionospheric structures as a key parameter for navigation error in GNSS applications and effects of planetary and gravity waves and gradients of the electron density on terrestrial and satellite communications.

Zolesi, B.; Cander, Lj. R.

31

Effects of the upper atmosphere on terrestrial and earth-space communications: final results of the eu cost271 action  

NASA Astrophysics Data System (ADS)

Project ``Effects of the Upper Atmosphere on Terrestrial and Earth-Space Communications (EACOS)'' was inaugurated as a four-year 271 Action in the Telecommunications and Information Science and Technology domain of the EU COST (Co-operation in the Field of Scientific and Technical Research) in October 2000. It follows two previous successful Actions COST 238 on PRIME (Prediction and Retrospective Ionospheric Modelling over Europe) and COST 251 on IITS (Improved Quality of Service in Ionospheric Telecommunication Systems Planning and Operation). The COST 271 Action (EACOS) has been oriented towards: (i) collection of new ionospheric and plasmaspheric data for now-casting and forecasting purposes, (ii) development methods and algorithms to predict and to minimise the effects of plasmaspheric-ionospheric perturbations and variations on communications; (iii) perform studies that influence the technical development and the implementation of new communication services, particularly for the GNSS and other advanced Earth-space and satellite to satellite applications; and (iv) dissemination and correlation of results, ideas and information which will provide a valuable support to European research centres and industry. This paper reviews the main results achieved in the COST 271 Action concerning in particular a range of the ionospheric space weather issues as: nowcasting, forecasting and warning tools, methods and supporting databases for ionospheric propagation prediction; total electron content variations and their use in the reconstruction of plasmaspheric-ionospheric structures as a key parameter for navigation error in GNSS applications and effects of planetary and gravity waves and gradients of the electron density on terrestrial and satellite communications.

Zolesi, B.; Cander, Lj.

32

Land Mobile Communications Satellite Missions (LAMOCOSAMIS) Task 3: Terrestrial System Concept.  

National Technical Information Service (NTIS)

Basic concepts for the definition of a pan-European terrestrial cellular radio system are reviewed: AMPS/TACS; C-450; MATS-E; NAMTS; and NMT. All the systems considered have good technical merit, TACS, C-450, and MATS-E have definite advantages over the o...

1985-01-01

33

Brief communication "Analysis of deformations in historic urban areas using terrestrial laser scanning"  

NASA Astrophysics Data System (ADS)

The terrestrial laser scanning (TLS) technique has been used to accurately reconstruct the 3-D shape of the walls and bastions of the historic city of Mdina (Malta) and underlying terrain. By applying this technique it has also been possible to extract additional quantitative information regarding weathering and deformational processes affecting the structures. Thus, with the aim of identifying the main instability mechanisms, a detailed 3-D crack distribution map has been drawn and the main displacement vectors have been defined.

Gigli, G.; Mugnai, F.; Leoni, L.; Casagli, N.

2009-11-01

34

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

NASA Astrophysics Data System (ADS)

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 Crimean Peninsula of the southern Ukraine in order to determine if the Upper Valanginian positive carbon-isotope excursion is expressed in the atmosphere. ?13C plant values fluctuate around - 23‰ to - 22‰ for the Valanginian-Hauterivian, except during the Upper Valanginian where ?13C plant values record a positive excursion to ˜- 18‰. Based upon ammonite biostratigraphy from Crimea, and in conjunction with a composite Tethyan marine ?13C carb curve, several conclusions can be drawn: (1) the ?13C plant record indicates that the atmospheric carbon reservoir was affected; (2) the defined ammonite correlations between Europe and Crimea are synchronous; and (3) a change in photosynthetic carbon-isotope fractionation, caused by a decrease in atmospheric pCO 2, occurred during the Upper Valanginian positive ?13C excursion. Our new data, combined with other paleoenvironmental and paleoclimatic information, indicate that the Upper Valanginian was a cool period (icehouse) and highlights that the Cretaceous period was interrupted by periods of cooling and was not an equable climate as previously thought.

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

2005-12-01

35

Terrestrial Communication Between Wireless Sensor Networks Using Beam- Forming and Space Division Multiple Access.  

National Technical Information Service (NTIS)

In this thesis, methods for forming a communications link of Wireless Sensor Networks (WSN) by enabling each WSN to act as a smart antenna are presented. Each WSN is simulated as a set of randomly placed sensor nodes within a planar area. The proposed met...

C. E. Taylor

2008-01-01

36

Free-space high data rate communications technologies for near terrestrial space  

Microsoft Academic Search

Recent progress at the Applied Physics Laboratory in high data rate communications technology development is described in this paper. System issues for developing and implementing high data rate downlinks from geosynchronous earth orbit to the ground, either for CONUS or in-theater users is considered. Technology is described that supports a viable dual-band multi-channel system concept. Modeling and simulation of micro-electro-mechanical

C. L. Edwards; J. R. Bruzzi; B. G. Boone

2008-01-01

37

Disaster drills and continuous medical education using satellite-based Internet.  

PubMed

We designed and evaluated a satellite-based Internet system for use in medical applications. Many experimental telemedicine projects use satellites, but we combined digital satellite communication with an ordinary telephone network to realize an economical countrywide network for emergency medicine and continuous medical education. The system appears to be a useful and practical technology for daily clinical activities. PMID:11191704

Okada, Y; Haruki, Y; Ogushi, Y

2000-12-01

38

Free-space high data rate communications technologies for near terrestrial space  

NASA Astrophysics Data System (ADS)

Recent progress at the Applied Physics Laboratory in high data rate communications technology development is described in this paper. System issues for developing and implementing high data rate downlinks from geosynchronous earth orbit to the ground, either for CONUS or in-theater users is considered. Technology is described that supports a viable dual-band multi-channel system concept. Modeling and simulation of micro-electro-mechanical systems (MEMS) beamsteering mirrors has been accomplished to evaluate the potential for this technology to support multi-channel optical links with pointing accuracies approaching 10 microradians. These models were validated experimentally down to levels in which Brownian motion was detected and characterized for single mirror devices only 500 microns across. This multi-channel beamsteering technology can be designed to address environmental compromises to free-space optical links, which derive from turbulence, clouds, as well as spacecraft vibration. Another technology concept is being pursued that is designed to mitigate the adverse effects of weather. It consists of a dual-band (RF/optical) antenna that is optimally designed in both bands simultaneously (e.g., Ku-band and near infrared). This technology would enable optical communications hardware to be seamlessly integrated with existing RF communications hardware on spacecraft platforms, while saving on mass and power, and improving overall system performance. These technology initiatives have been pursued principally because of potential sponsor interest in upgrading existing systems to accommodate quick data recovery and decision support, particularly for the warfighter in future conflicts where the exchange of large data sets such as high resolution imagery would have significant tactical benefits.

Edwards, C. L.; Bruzzi, J. R.; Boone, B. G.

2008-08-01

39

14 CFR 121.122 - Communications facilities-supplemental operations.  

Code of Federal Regulations, 2012 CFR

...this section. That system must be able to provide immediate satellite-based voice communications of landline telephone-fidelity...diversion to ETOPS Alternate Airports. Where immediate, satellite-based voice communications are not available, or are...

2014-01-01

40

Desktop video conferencing collaborative technology for planning satellite based communications  

Microsoft Academic Search

The described studies of desktop video conferencing collaborative work were conducted as part of a research initiative in developing computerized collaborative technology to support the US Air Force operational requirements process. Minimal research has been done integrating computer supported (CSCW) and desktop video into the operational desktop video conferencing technology is now revolutionizing collaboration at distance for teams distributed in

A. Bordetsky; F. Simcox

1997-01-01

41

Impact of space weather events on satellite-based navigation  

NASA Astrophysics Data System (ADS)

effects of the equatorial ionospheric irregularities on satellite-based communication and navigation systems have been studied over the past few decades as space weather events have the potential to seriously disturb the technological infrastructure of modern society. The present paper tries to understand operational compliance of Global Positioning System (GPS) receivers to International Civil Aviation Organization (ICAO) standards under scintillation conditions by recording the received phase of the L1(1575.42 MHz) signal from two stations, namely Calcutta situated near the northern crest of the Equatorial Ionization Anomaly and Siliguri, situated beyond the northern crest, at a subionospheric latitude separation of 4° along the same meridian. A causative approach is adopted whereby GPS phase scintillations have been monitored and receiver performance prior to loss of lock and cycle slips have been analyzed during August-October 2011 at Calcutta and September 2011 at Siliguri. The received phase at GPS-L1 frequency has often been found to fluctuate at kilohertz, often megahertz rates, thereby causing carrier-tracking loop malfunctions. It should be borne in mind that normal GPS receivers' carrier-tracking loops have a typical dynamic range of 14-18 Hz. Cycle slips have been observed with durations far exceeding ICAO specified levels for high dynamic platforms like aircrafts. Differences in cycle slips between Calcutta and Siliguri indicate possible evolution of irregularity structures even across small subionospheric swath. Significant improvement in present understanding of GPS phase scintillations should be developed and implemented in receiver designs prior to application of Satellite Based Augmentation System services for civil aviation, particularly in the geophysically sensitive equatorial region.

Roy, B.; DasGupta, A.; Paul, A.

2013-12-01

42

Proceedings of the Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications  

NASA Technical Reports Server (NTRS)

The Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications was held at NASA's JPL Laboratory on 30-31 May 1991. It provided a forum for reviewing the development of advanced network and technology concepts for turn-of-the-century telecommunications. The workshop was organized into three main categories: (1) Satellite-Based Networks (L-band, C-band, Ku-band, and Ka-band); (2) Terrestrial-Based Networks (cellular, CT2, PCN, GSM, and other networks); and (3) Hybrid Satellite/Terrestrial Networks. The proceedings contain presentation papers from each of the above categories.

Paul, Lori (editor)

1991-01-01

43

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

Microsoft Academic Search

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.

Daniel Irwin; Hrishikesh Venkataraman; Gabriel-Miro Muntean

2012-01-01

44

14 CFR 121.99 - Communications facilities-domestic and flag operations.  

Code of Federal Regulations, 2013 CFR

...this section. That system must be able to provide immediate satellite-based voice communications of landline-telephone fidelity...diversion to ETOPS Alternate Airports. Where immediate, satellite-based voice communications are not available, or are...

2014-01-01

45

Interoperability of satellite-based augmentation systems for aircraft navigation  

Microsoft Academic Search

The Federal Aviation Administration (FAA) is pioneering a transformation of the national airspace system from its present ground based navigation and landing systems to a satellite based system using the Global Positioning System (GPS). To meet the critical safety-of-life aviation positioning requirements, a Satellite-Based Augmentation System (SBAS), the Wide Area Augmentation System (WAAS), is being implemented to support navigation for

Donghai Dai

2001-01-01

46

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

DOEpatents

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.

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

2011-12-13

47

Multi-spectral band selection for satellite-based systems  

SciTech Connect

The design of satellite based multispectral imaging systems requires the consideration of a number of tradeoffs between cost and performance. The authors have recently been involved in the design and evaluation of a satellite based multispectral sensor operating from the visible through the long wavelength IR. The criteria that led to some of the proposed designs and the modeling used to evaluate and fine tune the designs will both be discussed. These criteria emphasized the use of bands for surface temperature retrieval and the correction of atmospheric effects. The impact of cost estimate changes on the final design will also be discussed.

Clodius, W.B.; Weber, P.G.; Borel, C.C.; Smith, B.W.

1998-09-01

48

Internetworking satellite and local exchange networks for personal communications applications  

NASA Technical Reports Server (NTRS)

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.

Wolff, Richard S.; Pinck, Deborah

1993-01-01

49

Satellite Based Synchronous Tutorials vs. Satellite Based Asynchronous Videocassettes: Factors Affecting Students' Attitudes and Choices.  

ERIC Educational Resources Information Center

The Open University of Israel (OUI) is a distance learning university. Learning is based mainly on textbooks and meetings with tutors in learning centers throughout the country. However, these meetings sometimes do not materialize. Synchronous virtual tutorials, via satellite communication from a studio at the university to classrooms throughout…

Beyth-Marom, Ruth; Saporta, Kelly

50

Participant Perceptions of a Collaborative Satellite-Based Mathematics Course.  

ERIC Educational Resources Information Center

Qualitative research methodology was used to explore the perceptions of students and teachers participating in an interactive collaborative satellite-based mathematics course in 21 high schools. Results showed that the distance learning format gives teachers access to more resources, is useful for underachieving students, and is an effective way…

Larson, Matthew R.; Bruning, Roger

1996-01-01

51

Satellite based permafrost modeling in low land tundra landscapes  

NASA Astrophysics Data System (ADS)

For most of the cryosphere components such as glaciers, ice sheets, sea ice, and snow satellite monitoring and change detection is well established since several decades. For permafrost, however, which represents the largest component of the Arctic cryosphere operational satellite monitoring schemes do not exist so far. Most of the processes which control the Arctic terrestrial ecosystems are related to the thermal state of permafrost and the freeze/thaw dynamics of the active layer. Hence, satellite based permafrost monitoring would be highly beneficial for the impact assessment of climate change in the Arctic. Permafrost monitoring could also be highly beneficial for the risk assessment of infrastructure in the Arctic such as roads, pipelines, and buildings which are directly affected by the thermal stability of permafrost. Increasing thaw depths and prolonged thaw periods can damage pipelines and interrupt the access to vast regions due to road damages. Sustained warming of permafrost can result in thermal erosion and landslides which threaten buildings and other infrastructural facilities. In this study we present a possible permafrost monitoring scheme based on a numerical heat flow model which is forced by multiple satellite products and initialized by weather reanalysis data. The used forcing and initialization dataset includes the land surface temperature (LST), the snow cover fraction (SCF), and the snow water equivalent (SWE). Previous studies demonstrated that MODIS LST products can deliver reasonable surface temperature measurements in tundra landscapes (Langer et al. 2010, Westermann et al. 2011). This study is based on the ten year record of the daily MOD11A1v5 and MYD11A1v5 land surface temperature products with a spatial resolution of 1km. The snow cover evolution is obtained from the daily GlobSnow SWE product with a spatial resolution of about 25km. In addition, the MODIS snow cover products MOD10A1v5 and MYD10v5 with a resolution of 1km are used in order to bridge large scale differences between the LST and SWE datasets. The model is initialized by a twenty year record of weather reanalysis (ERA-interim) and GlobSnow data. The proposed scheme is extensively tested at a typical low land permafrost site in the Lena River Delta in northern Siberia. The forcing data and model results are compared to field measurements of surface temperature, snow depth, permafrost temperature profiles, and active layer depth. The sensitivity of the model is evaluated by comprehensive Monte-Carlo simulations. References: Langer, M. , Westermann, S. and Boike, J. (2010): Spatial and temporal variations of summer surface temperatures of wet polygonal tundra in Siberia - implications for MODIS LST based permafrost monitoring, Remote Sensing of Environment, 114 (9), 2059-2069. Westermann, S. , Langer, M. and Boike, J. (2011): Spatial and temporal variations of summer surface temperatures of high-arctic tundra on Svalbard - Implications for MODIS LST based permafrost monitoring, Remote Sensing of Environment, 115 (3), 908 - 922.

Langer, M.; Westermann, S.; Heikenfeld, M.; Boike, J.

2012-12-01

52

Low-earth orbit global cellular communications network  

NASA Astrophysics Data System (ADS)

Technical aspects of the recently announced Iridium satellite communications system are discussed. The Iridium system is a worldwide, digital, satellite-based, cellular, personal communications system primarily intended to provide commercial, low-density, mobile service via portable, mobile, or transportable user units, employing low-profile antennas, to millions of users throughout the world. Calls can be made and received anywhere in the world with a personal, portable unit. Seventy-seven small (340 kg), smart satellites are internetted to form the network's backbone. Small, battery-powered, cellular-telephone-like user units communicate directly to the satellites. Gateways (earth stations) interface from the satellites to the individual Postal, Telephone and Telegraph Authorities (PTTs). The system is intended to complement the terrestrial cellular telephone systems installed, or being installed, in densely populated areas by providing a similar service everywhere else in the world.

Leopold, Raymond J.

53

The Need for Global, Satellite-based Observations of Terrestrial Surface Waters  

Microsoft Academic Search

River discharge as well as lake and wetland storage of water are critical terms in the surface water balance, yet they are poorly observed globally and the prospects for improvement from in-situ networks are bleak [e.g., Shiklomanov et al., 2002; IAHS, 2001; Stokstad, 1999]. Indeed, given our basic need for fresh water, perhaps the most important hydrologic observations that can

Doug Alsdorf; Dennis Lettenmaier; Charles Vörösmarty

2003-01-01

54

Role of Time and Frequency in the MTSAT Satellite-Based Augmentation System (MSAS).  

National Technical Information Service (NTIS)

The MTSAT Satellite-based Augmentation System (MSAS) is a satellite- based augmentation system (SBAS) for navigation. The MSAS is one of several applications that shares the use of the Multifunctional Transport Satellite (MTSAT), a geostationary earth orb...

A. S. Nii T. Ishita

1998-01-01

55

Terrestrial sequestration  

ScienceCinema

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.

Charlie Byrer

2010-01-08

56

Communication.  

ERIC Educational Resources Information Center

This theme issue on communication includes annotated listings of Web sites, CD-ROM and computer software, videos, books, and professional resources that deal with various methods of communication. Sidebars discuss mythology, photojournalism, sharing ideas on the Web, and songs of protest. Suggestions for class activities are also included. (LRW)

Online-Offline, 1998

1998-01-01

57

[Surveying a zoological facility through satellite-based geodesy].  

PubMed

In the course of a thesis submitted for a diploma degree within the Fachhochschule Oldenburg the Serengeti Safaripark was surveyed in autumn and winter 1996/97 laying in the planning foundations for the application for licences from the controlling authorities. Taking into consideration the special way of keeping animals in the Serengeti Safaripark (game ranching, spacious walk-through-facilities) the intention was to employ the outstanding satellite based geodesy. This technology relies on special aerials receiving signals from 24 satellites which circle around the globe. These data are being gathered and examined. This examination produces the exact position of this aerial in a system of coordinates which allows depicting this point on a map. This procedure was used stationary (from a strictly defined point) as well as in the movement (in a moving car). Additionally conventional procedures were used when the satellite based geodesy came to its limits. Finally a detailed map of the Serengeti Safaripark was created which shows the position and size of stables and enclosures as well as wood and water areas and the sectors of the leisure park. Furthermore the established areas of the enclosures together with an already existing animal databank have flown into an information system with the help of which the stock of animals can be managed enclosure-orientated. PMID:10916935

Böer, M; Thien, W; Tölke, D

2000-06-01

58

Communication  

Microsoft Academic Search

\\u000a Communication impairment is a core deficit associated with autism spectrum disorder (ASD). Therefore, it should not be surprising\\u000a that this topic has become a major thrust of assessment and treatment in applied behavior analysis (ABA). The types of communication\\u000a skills to target for intervention and the behavioral assessment methods that can be used to identify these target behaviors\\u000a are reviewed

Jeff Sigafoos; Mark F. O’Reilly; Giulio E. Lancioni

59

Measurement Uncertainty of Satellite-based Precipitation Sensors  

NASA Astrophysics Data System (ADS)

Uncertainties associated with satellite-based multi-sensor precipitation products are from two sources: the upstream sensors used and the algorithms to merge the sensor retrievals. Several satellite-based precipitation products, generated from disparate merging algorithms, share remarkable similarities in error characteristics, this suggests these errors can be traced back to their upstream sensor inputs. In the post 2013 era of the NASA's Global Precipitation Measurement (GPM) mission, it is critical for both data producers and users to understand the realistic limitations to which these satellite sensor inputs have and propagate to merged products. This paper presents results focusing on quantifying the measurement uncertainty of satellite precipitation sensors. Several Passive Microwave (PMW) precipitation sensors have been studied, including TMI, AMSR-R, SSM/I, MHS, and AMSU-B. A high-resolution ground radar-based dataset, the next generation multi-senor QPE (Q2) data over the contiguous U.S. is used as the ground reference. Additional quality control and quality assurance (QA/QC) have been performed on the reference data. The high spatial and temporal resolution of the reference data, allows rigorous collocation (within 10 minutes) and relatively more precise comparison with the satellite overpasses. From our results, PMW sensor retrievals exhibit fairly systematic bias varying by seasons and rain rates, with overestimates in summer at intermediate rain rates and underestimates in winter at high-end rain rates. This feature is also observed in the merged products, suggesting the dominant contribution of the sensor errors to merged products. In addition, at satellite snapshot scale, the false alarm and missed detection rates become much more significant.

Tang, L.; Tian, Y.; Lin, X.

2012-12-01

60

Communications.  

ERIC Educational Resources Information Center

Five articles discussing communications in vocational education include "The Golden Rule of Administration" by Ben Mortensen; "Vital Link with Parents" by Richard Sullivan; "An Interpersonal Exercise" by John Villiers; "Face to Face with Employers" by Gregg Bosak; and "Recruitment Strategies" by Susan Miller. (SK)

Mortensen, Ben F.; And Others

1981-01-01

61

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...

62

Operational Satellite-based Surface Oil Analyses (Invited)  

NASA Astrophysics Data System (ADS)

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.

Streett, D.; Warren, C.

2010-12-01

63

Terrestrial Planets  

NASA Astrophysics Data System (ADS)

The four terrestrial planets (Mercury, Venus, Earth, and Mars) and Earth's Moon display similar compositions, interior structures, and geologic histories. The terrestrial planets formed by accretion ˜ 4.5 Ga ago out of the solar nebula, whereas the Moon formed through accretion of material ejected off Earth during a giant impact event shortly after Earth formed. Geophysical investigations (gravity anomalies, seismic analysis, heat flow measurements, and magnetic field studies) reveal that all five bodies have differentiated into a low-density silicate crust, an intermediate density silicate mantle, and an iron-rich core. Seismic and heat flow measurements are only available for Earth and its Moon, and only Earth and Mercury currently exhibit actively produced magnetic fields (although Mars and the Moon retain remanent fields). Surface evolutions of all five bodies have been influenced by impact cratering, volcanism, tectonism, and mass wasting. Aeolian activity only occurs on bodies with a substantial atmosphere (Venus, Earth, and Mars) and only Earth and Mars display evidence of fluvial and glacial processes. Earth's volcanic and tectonic activity is largely driven by plate tectonics, whereas those processes on Venus result from vertical motions associated with hotspots and mantle upwellings. Mercury displays a unique tectonic regime of global contraction caused by gradual solidification of its large iron core. Early large impact events stripped away much of Mercury's crust and mantle, produced Venus' slow retrograde rotation, ejected material off Earth that became the Moon, and may have created the Martian hemispheric dichotomy. The similarities and differences between the interiors and surfaces of these five bodies provide scientists with a better understanding of terrestrial planet evolutionary paths.

Barlow, Nadine G.

64

GIO-EMS and International Collaboration in Satellite based Emergency Mapping  

NASA Astrophysics Data System (ADS)

During the last decade, satellite based emergency mapping has developed into a mature operational stage. The European Union's GMES Initial Operations - Emergency Management Service (GIO-EMS), is operational since April 2012. It's set up differs from other mechanisms (for example from the International Charter "Space and Major Disasters"), as it extends fast satellite tasking and delivery with the value adding map production as a single service, which is available, free of charge, to the authorized users of the service. Maps and vector datasets with standard characteristics and formats ranging from post-disaster damage assessment to recovery and disaster prevention are covered by this initiative. Main users of the service are European civil protection authorities and international organizations active in humanitarian aid. All non-sensitive outputs of the service are accessible to the public. The European Commission's in-house science service Joint Research Centre (JRC) is the technical and administrative supervisor of the GIO-EMS. The EC's DG ECHO Monitoring and Information Centre acts as the service's focal point and DG ENTR is responsible for overall service governance. GIO-EMS also aims to contribute to the synergy with similar existing mechanisms at national and international level. The usage of satellite data for emergency mapping has increased during the last years and this trend is expected to continue because of easier accessibility to suitable satellite and other relevant data in the near future. Furthermore, the data and analyses coming from volunteer emergency mapping communities are expected to further enrich the content of such cartographic products. In the case of major disasters the parallel activity of more providers is likely to generate non-optimal use of resources, e.g. unnecessary duplication; whereas coordination may lead to reduced time needed to cover the disaster area. Furthermore the abundant number of geospatial products of different characteristics and quality can become confusing for users. The urgent need for a better coordination has led to establishment of the International Working Group on Satellite Based Emergency Mapping (IWG-SEM). Members of the IWG-SEM, which include JRC, USGS, DLR-ZKI, SERVIR, Sentinel Asia, UNOSAT, UN-SPIDER, GEO, ITHACA and SERTIT have recognized the need to establish the best practice between operational satellite-based emergency mapping programs. The group intends to: • work with the appropriate organizations on definition of professional standards for emergency mapping, guidelines for product generation and reviewing relevant technical standards and protocols • facilitate communication and collaboration during the major emergencies • stimulate coordination of expertise and capacities. The existence of the group and the cooperation among members already brought benefits during recent disasters in Africa and Europe in 2012 in terms of faster and effective satellite data provision and better product generation.

Kucera, Jan; Lemoine, Guido; Broglia, Marco

2013-04-01

65

Terrestrial free space line of sight optical communication (TFSLSOC) using adaptive control steering system with laser beam Tracking, Aligning and Positioning (ATP)  

Microsoft Academic Search

Free space optical communication (FSOC) is the most promising approach for addressing the emerging broadband access network. Quick link setup, high transmission security, large bandwidth and light weight are some of the important features of this system. However, the laser power attenuation due to adverse weather conditions and scattering due to turbulence are to be mitigated. In this paper, a

A. Raj; J. Arputha Vijaya Selvi; S. Raghavan

2010-01-01

66

GLOBAL MOBILE SATELLITE COMMUNICATIONS: A REVIEW OF THREE CONTENDERS  

Microsoft Academic Search

The era of satellite-based mobile communications systems started with the first MARISAT satellite which was launched into a geostationary orbit over the Pacific Ocean in 1976 to provide communications between ships and shore stations. The combination of high cost and unacceptably large equipment has kept mobile satellite communications (MSC) systems from appealing to the wider market of personal mobile communications.

Gary M. Comparetto

1994-01-01

67

Advancement of Satellite-based Rainfall Applications for Hydrologic Modeling in Topographically Complex Regions  

NASA Astrophysics Data System (ADS)

Accuracy and reliability of hydrological modeling studies heavily depends on quality and availability of precipitation estimates. However hydrological studies in developing countries, especially over complex topography, are limited due to unavailability and scarcity of ground-based networks. Difficulties in representation of high rainfall variability using rain gauges make satellite-based rainfall retrieval algorithms potentially attractive for basin scale hydrologic modeling studies over complex topography. Even though satellite-based rainfall measurements are quasi global and high resolution, these products has limitations that necessitates a bias adjustment or merging procedure using more accurate rainfall products. To understand the limitations of the satellite-based rainfall measurements over topographically complex Western Black Sea Basin in Turkey, three different satellite-based rainfall retrieval algorithms namely, Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (TMPA), NOAA/Climate Prediction Center Morphing Method (CMORPH) and EUMETSAT's Multi-Sensor Precipitation Estimate (MPE) are evaluated using a relatively dense rain gauge network. Our results indicated that satellite-based products significantly underestimated the rainfall in regions characterized by orographic rainfall and overestimated the rainfall in the drier regions with seasonal dependency. Further, we devised a new bias adjustment algorithm for the satellite-based rainfall products based on the 'physiographic similarity' concept. Our results showed that proposed bias adjustment algorithm is better suited to regions with complex topography and provided improved results compared to the baseline 'inverse distance weighting' method. In this presentation we will provide a discussion of evaluation and bias correction of the satellite-based precipitation products and further provide an analysis of their utility in flood simulation over topographically complex regions using MIKE SHE-MIKE 11 integrated fully distributed physically based hydrological model.

Yilmaz, K. K.; Derin, Y.

2013-12-01

68

Global distribution and seasonal dependence of satellite-based whitecap fraction  

NASA Astrophysics Data System (ADS)

We present the first study of global seasonal distributions of whitecap fraction, W, obtained from satellite-based radiometric observations. Satellite-based W incorporates variability from forcings other than wind speed and can capture differences in W in initial and late lifetime stages. The satellite-based Wis more uniform latitudinally than predictions from a widely used wind speed-dependent parameterization, W(U10), formulated from in situ observations, being on average higher than the W(U10) predictions at low latitudes and lower at middle and high latitudes. This difference provides an explanation for the consistent geographical biases in sea spray aerosol concentration found in a number of large-scale models. Satellite estimates of W would benefit air-sea interaction and remote sensing applications that use parameterizations in terms of W such as sea spray flux, gas transfer, and surface winds.

Salisbury, Dominic J.; Anguelova, Magdalena D.; Brooks, Ian M.

2014-03-01

69

Advancement of Satellite-based Rainfall Applications for Hydrologic Modeling in Topographically Complex Regions  

NASA Astrophysics Data System (ADS)

Accuracy and reliability of hydrological modeling studies heavily depends on quality and availability of precipitation estimates. However hydrological studies in developing countries, especially over complex topography, are limited due to unavailability and scarcity of ground-based networks. In this study we evaluate three different satellite-based rainfall retrieval algorithms namely, Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (TMPA), NOAA/Climate Prediction Center Morphing Method (CMORPH) and EUMETSAT's Multi-Sensor Precipitation Estimate (MPE) over orographically complex Western Black Sea Basin in Turkey, using a relatively dense rain gauge network. Our results indicated that satellite-based products significantly underestimated the rainfall in regions characterized by orographic rainfall and overestimated the rainfall in the drier regions with seasonal dependency. Further, we devised a new bias adjustment algorithm for the satellite-based rainfall products based on the "physiographic similarity" concept. Our results showed that proposed bias adjustment algorithm is better suited to regions with complex topography and provided improved results compared to the baseline "inverse distance weighting" method. To evaluate the utility of satellite-based products in hydrologic modeling studies, we implemented the MIKE SHE-MIKE 11 integrated fully distributed physically based hydrological model in the study region driven by ground-based and satellite-based precipitation estimates. Model parameter estimation was performed using a constrained calibration approach guided by multiple "signature measures" to estimate model parameters in a hydrologically meaningful way rather than using the traditional "statistical" objective functions that largely mask valuable hydrologic information during calibration process. In this presentation we will provide a discussion of evaluation and bias correction of the satellite-based precipitation products and further provide an analysis of their utility in flood simulation over topographically complex regions.

Yilmaz, Koray; Derin, Yagmur

2014-05-01

70

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

NASA Technical Reports Server (NTRS)

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.

Emmitt, G. D.

1985-01-01

71

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

72

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

Microsoft Academic Search

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

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

2010-01-01

73

Bias-adjusted satellite-based rainfall estimates for predicting floods: Narayani Basin  

USGS Publications Warehouse

In Nepal, as the spatial distribution of rain gauges is not sufficient to provide detailed perspective on the highly varied spatial nature of rainfall, satellite-based rainfall estimates provides the opportunity for timely estimation. This paper presents the flood prediction of Narayani Basin at the Devghat hydrometric station (32000km2) using bias-adjusted satellite rainfall estimates and the Geospatial Stream Flow Model (GeoSFM), a spatially distributed, physically based hydrologic model. The GeoSFM with gridded gauge observed rainfall inputs using kriging interpolation from 2003 was used for calibration and 2004 for validation to simulate stream flow with both having a Nash Sutcliff Efficiency of above 0.7. With the National Oceanic and Atmospheric Administration Climate Prediction Centre's rainfall estimates (CPC-RFE2.0), using the same calibrated parameters, for 2003 the model performance deteriorated but improved after recalibration with CPC-RFE2.0 indicating the need to recalibrate the model with satellite-based rainfall estimates. Adjusting the CPC-RFE2.0 by a seasonal, monthly and 7-day moving average ratio, improvement in model performance was achieved. Furthermore, a new gauge-satellite merged rainfall estimates obtained from ingestion of local rain gauge data resulted in significant improvement in flood predictability. The results indicate the applicability of satellite-based rainfall estimates in flood prediction with appropriate bias correction. ?? 2011 The Authors. Journal of Flood Risk Management ?? 2011 The Chartered Institution of Water and Environmental Management.

Shrestha, M. S.; Artan, G. A.; Bajracharya, S. R.; Gautam, D. K.; Tokar, S. A.

2011-01-01

74

Bias-adjusted satellite-based rainfall estimates for predicting floods: Narayani Basin  

USGS Publications Warehouse

In Nepal, as the spatial distribution of rain gauges is not sufficient to provide detailed perspective on the highly varied spatial nature of rainfall, satellite-based rainfall estimates provides the opportunity for timely estimation. This paper presents the flood prediction of Narayani Basin at the Devghat hydrometric station (32?000?km2) using bias-adjusted satellite rainfall estimates and the Geospatial Stream Flow Model (GeoSFM), a spatially distributed, physically based hydrologic model. The GeoSFM with gridded gauge observed rainfall inputs using kriging interpolation from 2003 was used for calibration and 2004 for validation to simulate stream flow with both having a Nash Sutcliff Efficiency of above 0.7. With the National Oceanic and Atmospheric Administration Climate Prediction Centre's rainfall estimates (CPC_RFE2.0), using the same calibrated parameters, for 2003 the model performance deteriorated but improved after recalibration with CPC_RFE2.0 indicating the need to recalibrate the model with satellite-based rainfall estimates. Adjusting the CPC_RFE2.0 by a seasonal, monthly and 7-day moving average ratio, improvement in model performance was achieved. Furthermore, a new gauge-satellite merged rainfall estimates obtained from ingestion of local rain gauge data resulted in significant improvement in flood predictability. The results indicate the applicability of satellite-based rainfall estimates in flood prediction with appropriate bias correction.

Guleid A Artan; Tokar, S. A.; Gautam, D. K.; Bajracharya, S. R.; Shrestha, M. S.

2011-01-01

75

Japanese Global Precipitation Measurement (GPM) mission status and application of satellite-based global rainfall map  

NASA Astrophysics Data System (ADS)

As accuracy of satellite precipitation estimates improves and observation frequency increases, application of those data to societal benefit areas, such as weather forecasts and flood predictions, is expected, in addition to research of precipitation climatology to analyze precipitation systems. There is, however, limitation on single satellite observation in coverage and frequency. Currently, the Global Precipitation Measurement (GPM) mission is scheduled under international collaboration to fulfill various user requirements that cannot be achieved by the single satellite, like the Tropical Rainfall Measurement Mission (TRMM). The GPM mission is an international mission to achieve high-accurate and high-frequent rainfall observation over a global area. GPM is composed of a TRMM-like non-sun-synchronous orbit satellite (GPM core satellite) and constellation of satellites carrying microwave radiometer instruments. The GPM core satellite carries the Dual-frequency Precipitation Radar (DPR), which is being developed by the Japan Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT), and microwave radiometer provided by the National Aeronautics and Space Administration (NASA). Development of DPR instrument is in good progress for scheduled launch in 2013, and DPR Critical Design Review has completed in July - September 2009. Constellation satellites, which carry a microwave imager and/or sounder, are planned to be launched around 2013 by each partner agency for its own purpose, and will contribute to extending coverage and increasing frequency. JAXA's future mission, the Global Change Observation Mission (GCOM) - Water (GCOM-W) satellite will be one of constellation satellites. The first generation of GCOM-W satellite is scheduled to be launched in 2011, and it carries the Advanced Microwave Scanning Radiometer 2 (AMSR2), which is being developed based on the experience of the AMSR-E on EOS Aqua satellite. Collaboration with GCOM-W is not only limited to its participation to GPM constellation but also coordination in areas of algorithm development and validation in Japan. Generation of high-temporal and high-accurate global rainfall map is one of targets of the GPM mission. As a proto-type for GPM era, JAXA has developed and operates the Global Precipitation Map algorithm in near-real-time since October 2008, and hourly and 0.1-degree resolution binary data and images available at http://sharaku.eorc.jaxa.jp/GSMaP/ four hours after observation. The algorithms are based on outcomes from the Global Satellite Mapping for Precipitation (GSMaP) project, which was sponsored by the Japan Science and Technology Agency (JST) under the Core Research for Evolutional Science and Technology (CREST) framework between 2002 and 2007 (Okamoto et al., 2005; Aonashi et al., 2009; Ushio et al., 2009). Target of GSMaP project is to produce global rainfall maps that are highly accurate and in high temporal and spatial resolution through the development of rain rate retrieval algorithms based on reliable precipitation physical models by using several microwave radiometer data, and comprehensive use of precipitation radar and geostationary infrared imager data. Near-real-time GSMaP data is distributed via internet and utilized by end users. Purpose of data utilization by each user covers broad areas and in world wide; Science researches (model validation, data assimilation, typhoon study, etc.), weather forecast/service, flood warning and rain analysis over river basin, oceanographic condition forecast, agriculture, and education. Toward the GPM era, operational application should be further emphasized as well as science application. JAXA continues collaboration with hydrological communities to utilize satellite-based precipitation data as inputs to future flood prediction and warning system, as well as with meteorological agencies to proceed further data utilization in numerical weather prediction system and forecasts.

Kachi, Misako; Shimizu, Shuji; Kubota, Takuji; Yoshida, Naofumi; Oki, Riko; Kojima, Masahiro; Iguchi, Toshio; Nakamura, Kenji

2010-05-01

76

Fade-Free Mobile Communication  

NASA Technical Reports Server (NTRS)

Scheme for mobile communication reduces multipath fading and interference between adjacent channels. Proposed communication system lends itself to almost completely digital implementation, eliminating costly and bulky crystal filters. Scheme suitable for satellite-aided or terrestrial mobile communication, including cellular mobile telephony, at frequencies in 150-to-900-MHz range.

Stevenson, C. R.

1986-01-01

77

Application of a satellite communication and location system for bomb damage assessment.  

National Technical Information Service (NTIS)

The Global Verification and Location System (GVLS) is a satellite based communication package proposed for the Global Positioning System (GPS) Block IIR satellites. This system provides the capability to relay bursts of information from small, low power m...

J. P. Kern

1994-01-01

78

Trellis-coded CPM for wireless communications  

Microsoft Academic Search

A coded modulation scheme based on trellis codes combined with continuous-phase modulated (CPM) signals is considered. Trellis-coded CPM (TCCPM) is a coded modulation technique for the transmission of digital information over bandwidth- and power-limited channels such as satellite-based terrestrial radio links (MSAT). While trellis codes provide power efficiency, the choice of CPM yields constant-envelope signals with good spectral properties. The

F. Abrishamkar; E. Biglieri

1993-01-01

79

Handover Management Optimization for LTE Terrestrial Network with Satellite Backhaul  

Microsoft Academic Search

Long Term Evolution (LTE) prevails as the next 4 th generation of mobile communications. Hybrid satellite and terrestrial LTE network takes advantages from the large satellite coverage for several emergency applications, such as providing civil security communications. In this paper we propose a LTE architecture partly composed of an integrated component with satellite backhaul on the LTE-S1 interface. Since ensuring

Michael Crosnier; Fabrice Planchou; Riadh Dhaou; Andre-Luc Beylot

2011-01-01

80

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...

81

Terrestrial Planets: Comparative Planetology  

NASA Technical Reports Server (NTRS)

Papers were presented at the 47th Annual Meteoritical Society Meeting on the Comparative planetology of Terrestrial Planets. Subject matter explored concerning terrestrial planets includes: interrelationships among planets; plaentary evolution; planetary structure; planetary composition; planetary Atmospheres; noble gases in meteorites; and planetary magnetic fields.

1985-01-01

82

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

83

Satellite-based assessment of water requirement for biofuel feedstock production in Maui, Hawaii  

NASA Astrophysics Data System (ADS)

Water availability is one of the limiting factors for sustainable production of biofuel crops. A common method for determining crop water requirement is to multiply daily potential evapotranspiration (ETo) calculated from meteorological parameters by a crop coefficient (Kc) to obtain actual crop evapotranspiration (ETc). Remote sensing data can provide dynamic Kc values that better reflect plant water use. In this study, an algorithm is being developed to estimate sugarcane Kc using normalized difference vegetation index (NDVI) obtained from Landsat 7 satellite images. Crop canopy cover was measured with a handheld multispectral camera from two sugarcane fields at the Hawaiian Commercial & Sugar Company (HC&S) plantation during the Landsat 7 satellite overpass days. An Eddy Covariance (EC) tower system was set up within each of these two fields and gathered EC flux at a 30-minute interval. Reference evapotranspiration was calculated from the network of automated weather stations at HC&S plantation using a modified Penman equation. Crop canopy cover was highly correlated with satellite NDVI values. A linear relationship between NDVI and measured Kc was obtained. Satellite -based ETc maps of HC&S plantation were developed using the NDVI-based Kc values and reference ET from HC&S weather station network. The satellite-based ETc was compared and validated with field measurements of ET using Eddy Covariance tower. A series of satellite-based ETc maps were developed to indicate the water demand of sugarcane plants at HC&S plantation. These results validate the use of satellite imagery as a tool for estimation of ET of sugarcane plants in Maui, Hawaii.

Zhang, H.; Anderson, R. G.; Wang, D.

2012-12-01

84

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

NASA Astrophysics Data System (ADS)

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.

Shen, Yan; Chen, Zhuoqi

2013-04-01

85

Evaluation of Level-2 Precipitation Estimates from Satellite-based Passive Microwave Radiometers  

NASA Astrophysics Data System (ADS)

NASA's satellite-based precipitation data records are produced in two levels: level 2 and 3. Level-2 products are derived from satellite sensors at their footprint scales, while level-3 products are typically gridded data using multiple level-2 products and other sensors. Satellite-based multi-sensor rainfall products (level-3), mainly generated from Passive Microwave (PMW) sensor rainfall retrievals (level-2), have been among the most widely used rainfall datasets in various hydrological applications. However, satellite-based multi-sensor rainfall estimates contain errors which need ground validation (GV). Errors associated with these products are from two sources: the upstream sensors used and the algorithms to merge the sensor retrievals. Many previous researches (e.g., Tian et. al., 2009) have proved that, several satellite-based multi-sensor rainfall products, generated from disparate merging algorithms, share remarkable similarities in error characteristics. This suggests these errors can be traced back to their upstream sensor inputs. This paper is focusing on evaluating the measurement errors of the upstream passive microwave radiometers (using the level-2 products). Five PMW radiometers on board nine satellites have been studied, including both imagers (TMI, AMSR-E, SSM/I) and sounders (AMSU-B and MHS). A high-resolution ground radar-based dataset, the next generation multi-sensor QPE (Q2) data over the continental US, has been used as the GV data. The high spatial and temporal resolution of the reference data, allows rigorous collocation (within 5 minutes) and relatively more precise comparison with satellite overpasses. From our results, PMW sensor retrievals exhibit fairly systematic bias varying be seasons and rain intensity, with overestimates in summer at intermediate to high-end rain rates and underestimates in winter at intermediate rain rates. This feature is also observed in the merged products, suggesting the dominant contribution of the sensor errors to merged products. Our study also reveals that rain retrievals from the imagers have less bias than those from the sounders, especially in summer.

Tang, L.; Tian, Y.; Lin, X.

2013-12-01

86

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

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

87

Measurements and estimation of CO2 fluxes from aircraft and satellite-based systems  

NASA Astrophysics Data System (ADS)

This study investigates the relationships between airborne observations of CO2 fluxes and satellite-based vegetation indices using data from the First International Land Surface Climatology Project Field Experiment (FIFE) 1989. The CO2 flux data were obtained by flying a grid pattern at a mean altitude of 90 m over a 225 km2 grassland ecosystem, on six occasions during a 2-week period. Two satellite-based data sets were obtained from NOAA 10 advanced very high resolution radiometer (AVHRR) and one from Landsat 5 thematic mapper (TM). Linear relationships Fc = b SR* + a were found between CO2 flux data (Fc) and footprint-weighted simple ratios (SR*) from the various satellites. These relationships improved significantly when the footprint was adjusted with the continuously changing wind conditions and with an empirical parameter that accounts for effects of surface roughness and stability on the diffusion pattern between the surface and the airborne sampling locations. The AVHRR data collected on July 28 accounted for 53 to 81% of the variations in CO2 flux measured during the six grid flights over the site and the Landsat TM data collected on August 4 accounted for 68 to 83% of the same CO2 variations. The regression coefficient b, which is related to the photosynthetic efficiency, appears to be an excellent way to characterize the dynamic response of complex ecosystems, and the flux (Fc) at SR* = 1.5 provides an estimate of soil respiration as shown through a comparison with enclosure measurements.

Desjardins, R. L.; Pelletier, R.; Schuepp, P. H.; MacPherson, J. I.; Hayhoe, H.; Cihlar, J.

1995-12-01

88

Dietary characterization of terrestrial mammals.  

PubMed

Understanding the feeding behaviour of the species that make up any ecosystem is essential for designing further research. Mammals have been studied intensively, but the criteria used for classifying their diets are far from being standardized. We built a database summarizing the dietary preferences of terrestrial mammals using published data regarding their stomach contents. We performed multivariate analyses in order to set up a standardized classification scheme. Ideally, food consumption percentages should be used instead of qualitative classifications. However, when highly detailed information is not available we propose classifying animals based on their main feeding resources. They should be classified as generalists when none of the feeding resources constitute over 50% of the diet. The term 'omnivore' should be avoided because it does not communicate all the complexity inherent to food choice. Moreover, the so-called omnivore diets actually involve several distinctive adaptations. Our dataset shows that terrestrial mammals are generally highly specialized and that some degree of food mixing may even be required for most species. PMID:25009067

Pineda-Munoz, Silvia; Alroy, John

2014-08-22

89

Terrestrial photovoltaic measurements, 2  

NASA Technical Reports Server (NTRS)

The following major topics are discussed; (1) Terrestrial solar irradiance; (2) Solar simulation and reference cell calibration; and (3) Cell and array measurement procedures. Numerous related subtopics are also discussed within each major topic area.

1976-01-01

90

Terrestrial and Extraterrestrial Fullerenes  

Microsoft Academic Search

This paper reviews reports of occurrences of fullerenes in circumstellar media, interstellar media, meteorites, interplanetary dust particles (IDPs), lunar rocks, hard terrestrial rocks from Shunga (Russia), Sudbury (Canada) and Mitov (Czech Republic), coal, terrestrial sediments from the Cretaceous?Tertiary?Boundary and Permian?Triassic?Boundary, fulgurite, ink sticks, dinosaur eggs, and a tree char. The occurrences are discussed in the context of known and postulated

D. Heymann; L. W. Jenneskens; J. Jehli?ka; Carola Koper; E. J. Vlietstra

2003-01-01

91

Extra Terrestrial Lava Flows  

NASA Technical Reports Server (NTRS)

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.

Lopes-Gautier, R.

1993-01-01

92

NASA'S communications programs - 1985  

NASA Astrophysics Data System (ADS)

NASA's communications program was restructured in 1979 to develop selective high risk technology forced on relief of the orbit and frequency congestion and on developing new and affordable service. The central theme of the current technology thrust is one of developing interconnectivity technology and architecture to convert the present era of bent pipe satellite utilization to one using nodal points in space for both space and earth based information gateways and interfaces to terrestrial communication systems.

Lovell, R. R.; Cuccia, C. L.

93

Interworking evolution of mobile satellite and terrestrial networks  

NASA Technical Reports Server (NTRS)

There is considerable interest among mobile satellite service providers in interworking with terrestrial networks to provide a universal global network. With such interworking, subscribers may be provided a common set of services such as those planned for the Public Switched Telephone Network (PSTN), the Integrated Services Digital Network (ISDN), and future Intelligent Networks (IN's). This paper first reviews issues in satellite interworking. Next the status and interworking plans of terrestrial mobile communications service providers are examined with early examples of mobile satellite interworking including a discussion of the anticipated evolution towards full interworking between mobile satellite and both fixed and mobile terrestrial networks.

Matyas, R.; Kelleher, P.; Moller, P.; Jones, T.

1993-01-01

94

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

95

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

NASA Technical Reports Server (NTRS)

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.

Bos, Andre; Callies, Jorg; Lefebvre, Alain

1995-01-01

96

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

NASA Astrophysics Data System (ADS)

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.

Nonnenmacher, L.; Coimbra, C.

2013-12-01

97

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

NASA Astrophysics Data System (ADS)

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.

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

98

Arctic terrestrial ecosystem contamination.  

PubMed

Limited data have been collected on the presence of contaminants in the Arctic terrestrial ecosystem, with the exception of radioactive fallout from atmospheric weapons testing. Although southern and temperate biological systems have largely cleansed themselves of radioactive fallout deposited during the 1950s and 1960s, Arctic environments have not. Lichens accumulate radioactivity more than many other plants because of their large surface area and long life span; the presence and persistence of radioisotopes in the Arctic is of concern because of the lichen----reindeer----human ecosystem. Effective biological half-life of cesium 137 is reckoned to be substantially less than its physical half-life. The database on organochlorines in Canadian Arctic terrestrial mammals and birds is very limited, but indications are that the air/plant/animal contaminant pathway is the major route of these compounds into the terrestrial food chain. For terrestrial herbivores, the most abundant organochlorine is usually hexachlorobenzene followed by hexachlorocyclohexane isomers. PCB accumulation favours the hexachlorobiphenyl, pentachlorobiphenyl and heptachlorobiphenyl homologous series. The concentrations of the various classes of organochlorine compounds are substantially lower in terrestrial herbivore tissues than in marine mammal tissues. PCBs and DDT are the most abundant residues in peregrine falcons (a terrestrial carnivore) reaching average levels of 9.2 and 10.4 micrograms.g-1, respectively, more than 10 times higher than other organochlorines and higher than in marine mammals, including the polar bear. Contaminants from local sources include metals from mining activities, hydrocarbons and waste drilling fluids from oil and gas exploration and production, wastes from DEW line sites, naturally occurring radionuclides associated with uranium mineralization, and smoke containing SO2 and H2SO4 aerosol from the Smoking Hills at Cape Bathurst, N.W.T. PMID:1355310

Thomas, D J; Tracey, B; Marshall, H; Norstrom, R J

1992-07-15

99

High-Performance Satellite/Terrestrial-Network Gateway  

NASA Technical Reports Server (NTRS)

A gateway has been developed to enable digital communication between (1) the high-rate receiving equipment at NASA's White Sands complex and (2) a standard terrestrial digital communication network at data rates up to 622 Mb/s. The design of this gateway can also be adapted for use in commercial Earth/satellite and digital communication networks, and in terrestrial digital communication networks that include wireless subnetworks. Gateway as used here signifies an electronic circuit that serves as an interface between two electronic communication networks so that a computer (or other terminal) on one network can communicate with a terminal on the other network. The connection between this gateway and the high-rate receiving equipment is made via a synchronous serial data interface at the emitter-coupled-logic (ECL) level. The connection between this gateway and a standard asynchronous transfer mode (ATM) terrestrial communication network is made via a standard user network interface with a synchronous optical network (SONET) connector. The gateway contains circuitry that performs the conversion between the ECL and SONET interfaces. The data rate of the SONET interface can be either 155.52 or 622.08 Mb/s. The gateway derives its clock signal from a satellite modem in the high-rate receiving equipment and, hence, is agile in the sense that it adapts to the data rate of the serial interface.

Beering, David R.

2005-01-01

100

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

NASA Astrophysics Data System (ADS)

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.

Ramarohetra, J.; Sultan, B.

2012-04-01

101

Satellite-based Estimates of Ambient Air Pollution and Global Variations in Childhood Asthma Prevalence  

PubMed Central

Background: The effect of ambient air pollution on global variations and trends in asthma prevalence is unclear. Objectives: Our goal was to investigate community-level associations between asthma prevalence data from the International Study of Asthma and Allergies in Childhood (ISAAC) and satellite-based estimates of particulate matter with aerodynamic diameter < 2.5 µm (PM2.5) and nitrogen dioxide (NO2), and modelled estimates of ozone. Methods: We assigned satellite-based estimates of PM2.5 and NO2 at a spatial resolution of 0.1° × 0.1° and modeled estimates of ozone at a resolution of 1° × 1° to 183 ISAAC centers. We used center-level prevalence of severe asthma as the outcome and multilevel models to adjust for gross national income (GNI) and center- and country-level sex, climate, and population density. We examined associations (adjusting for GNI) between air pollution and asthma prevalence over time in centers with data from ISAAC Phase One (mid-1900s) and Phase Three (2001–2003). Results: For the 13- to 14-year age group (128 centers in 28 countries), the estimated average within-country change in center-level asthma prevalence per 100 children per 10% increase in center-level PM2.5 and NO2 was –0.043 [95% confidence interval (CI): –0.139, 0.053] and 0.017 (95% CI: –0.030, 0.064) respectively. For ozone the estimated change in prevalence per parts per billion by volume was –0.116 (95% CI: –0.234, 0.001). Equivalent results for the 6- to 7-year age group (83 centers in 20 countries), though slightly different, were not significantly positive. For the 13- to 14-year age group, change in center-level asthma prevalence over time per 100 children per 10% increase in PM2.5 from Phase One to Phase Three was –0.139 (95% CI: –0.347, 0.068). The corresponding association with ozone (per ppbV) was –0.171 (95% CI: –0.275, –0.067). Conclusion: In contrast to reports from within-community studies of individuals exposed to traffic pollution, we did not find evidence of a positive association between ambient air pollution and asthma prevalence as measured at the community level.

Butland, Barbara K.; van Donkelaar, Aaron; Brauer, Michael; Strachan, David P.; Clayton, Tadd; van Dingenen, Rita; Amann, Marcus; Brunekreef, Bert; Cohen, Aaron; Dentener, Frank; Lai, Christopher; Lamsal, Lok N.; Martin, Randall V.; One, ISAAC Phase

2012-01-01

102

a Satellite-Based Approach for Evaluation of the Spatial Distribution of Evapotranspiration from Agricultural Lands.  

NASA Astrophysics Data System (ADS)

The ultimate goal of this dissertation was to produce maps of surface evaporation for agricultural areas based on Landsat Thematic Mapper (TM) spectral data. This achievement was dependent upon successful attainment of four intermediate goals: (1) Enhancement of TM thermal spatial resolution; (2) Atmospheric correction of TM visible and near-IR spectral data; (3) Atmospheric correction of TM thermal data; and (4) Remote estimation of crop aerodynamic properties. A statistical technique was developed to combine low-resolution (120 m) TM thermal data (TM6) with higher resolution (30 m) TM reflective data based on the relation between TM6 and the TM red and near-IR wavebands. This method was successful in improving the visible appearance of the TM6 image and retaining the original thermal spectral information over diverse agricultural landscapes. Several atmospheric correction procedures were examined to determine which techniques could provide the ease and accuracy necessary for the remote ET model. The Lowtran7 radiative transfer code was chosen for correction of TM visible and near-IR data (TM1-TM4) because it provided adequate accuracy (+/-0.02 reflectance, 1 sigma RMS) and easy application. For TM6, results using the Lowtran7 code with a variety of atmospheric models were unsatisfactory. However, a simple linear regression of measured surface temperatures (T _{rm s}) and TM6 digital numbers provided estimates of T_{rm s} to within +/-1.2 ^circC of measured values. Though the procedure was accurate, it required concurrent ground -based measurements of T_{rm s } and would obviously be inconvenient if it were used on an operational basis. Reasonable estimates of aerodynamic parameters were made for an alfalfa canopy from remote measurements of red and near-IR reflectance. The uncertainty in sensible heat flux density associated with the error in remote estimates of aerodynamic resistance was +/-25%. Since these results were probably crop-specific and possibly site-specific, more data sets of this nature will need to be collected for other crops to determine a universal relation between remotely sensed data and aerodynamic properties. Data from the satellite-based TM sensor and ground -based meteorological instruments were combined to produce maps of latent heat flux density (LE: a function of evaporation rate (E) and heat of vaporization (L)) for Maricopa Agricultural Center, Arizona. The satellite-based estimates of LE differed from coincident ground-based measurements, using a Bowen -ratio apparatus, by 4% in cotton and -6% in alfalfa. These results were within the suggested accuracy goal of +/-11%.

Moran, Mary Susan

1990-01-01

103

Satellite-Terrestrial Network Interoperability  

NASA Technical Reports Server (NTRS)

The developing national and global information infrastructures (NII/GII) are being built upon the asynchronous transfer mode (ATM) telecommunications protocol and associated protocol standards. These protocols are themselves under development through the telecommunications standards process defined by the International Telecommunications Union (ITU), which as a body is sanctioned by the United Nations. All telecommunications manufacturers use these standards to create products that can interoperate. The ITU has recognized the ATM Forum as the instrument for the development of ATM protocols. This forum is a consortium of industry, academia, and government entities formed to quickly develop standards for the ATM infrastructure. However, because the participants represent a predominately terrestrial network viewpoint, the use of satellites in the national and global information infrastructures could be severely compromised. Consequently, through an ongoing task order, the NASA Lewis Research Center asked Sterling Software, Inc., to communicate with the ATM Forum in support of the interoperability of satellite-terrestrial networks. This year, Dr. Raj Jain of the Ohio State University, under contract to Sterling, authored or coauthored 32 explanatory documents delivered to the ATM Forum in the areas of Guaranteed Frame Rate for Transmission Control Protocol/Internet Protocol (TCP/IP), Available Bit Rate, performance testing, Variable Bit Rate voice over ATM, TCP over Unspecified Bit Rate+, Virtual Source/Virtual Destination, and network management. These contributions have had a significant impact on the content of the standards that the ATM Forum is developing. Some of the more significant accomplishments have been: (1) The adoption by the ATM Forum of a new definition for Message-In, Message-Out latency; and (2) Improved text (clearer wording and newly defined terms) for measurement procedures, foreground and background traffic, and scalable configuration in the latency and throughput sections of the Performance Testing Baseline Text.

vonDeak, Thomas C.

1998-01-01

104

Terrestrial planet formation.  

PubMed

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

Righter, K; O'Brien, D P

2011-11-29

105

INTRODUCED TERRESTRIAL SPECIES (FUTURE)  

EPA Science Inventory

These data represent predicted future potential distributions of terrestrial plants, animals, and pathogens non-native to the Middle-Atlantic region. These data are available for 8-digit HUCs. The data are a weighted proportion of appropriate habitat overlapped by the potential...

106

Terrestrial photovoltaic measurement procedures  

NASA Technical Reports Server (NTRS)

Procedures for obtaining cell and array current-voltage measurements both outdoors in natural sunlight and indoors in simulated sunlight are presented. A description of the necessary apparatus and equipment is given for the calibration and use of reference solar cells. Some comments relating to concentration cell measurements, and a revised terrestrial solar spectrum for use in theoretical calculations, are included.

1977-01-01

107

Terrestrial planet formation  

PubMed Central

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.

Righter, K.; O'Brien, D. P.

2011-01-01

108

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...

109

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

Microsoft Academic Search

One of the biggest obstacles for the average Earth science student today is locating and obtaining satellite- based remote sensing datasets 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

S. A. Lloyd; J. G. Acker; A. I. Prados; G. G. Leptoukh

2008-01-01

110

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

Microsoft Academic Search

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,

D. R. Myers

2009-01-01

111

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 ...

112

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

NASA Astrophysics Data System (ADS)

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.

Tang, Ling; Tian, Yudong; Lin, Xin

2014-04-01

113

Intrusion of coastal waters into the pelagic eastern Mediterranean: in situ and satellite-based characterization  

NASA Astrophysics Data System (ADS)

A combined dataset of near-real-time multi-satellite observations and in situ measurements from a high-resolution survey is used for characterizing physical-biogeochemical properties of a patch stretching from the coast to the open sea in the Levantine Basin (LB) of the eastern Mediterranean (EM). Spatial analysis of the combined dataset indicates that the patch is a semi-enclosed system, bounded within the mixed layer and separated from ambient waters by transport barriers induced by horizontal stirring. As such, the patch is characterized by physical-biogeochemical properties that significantly differ from those of the waters surrounding it, with lower salinity and higher temperatures, concentrations of silicic acid and chlorophyll a, and abundance of Synechococcus and picoeukaryote cells. Based on estimates of patch dimensions (∼40 km width and ∼25 m depth) and propagation speed (∼0.09 m s-1), the volume flux associated with the patch is found to be on the order of 0.1 Sv. Our observations suggest that horizontal stirring by surface currents is likely to have an important impact on the ultra-oligotrophic Levantine Basin ecosystem, through (1) transport of nutrients and coastally derived material, and (2) formation of local, dynamically isolated niches. In addition, this work provides a satellite-based framework for planning and executing high-resolution sampling strategies in the interface between the coast and the open sea.

Efrati, S.; Lehahn, Y.; Rahav, E.; Kress, N.; Herut, B.; Gertman, I.; Goldman, R.; Ozer, T.; Lazar, M.; Heifetz, E.

2013-05-01

114

Intrusion of coastal waters into the pelagic eastern mediterranean: in situ and satellite-based characterization  

NASA Astrophysics Data System (ADS)

A combined dataset of near real time multi-satellite observations and in situ measurements from a high resolution survey, is used for characterizing physical-biogeochemical properties of a patch stretching from the coast to the open sea in the Levantine basin of the eastern Mediterranean. Spatial analysis of the combined dataset indicates that the patch is a semi-enclosed system, bounded within the mixed layer and separated from ambient waters by transport barriers induced by horizontal stirring. As such, the patch is characterized by physical-biogeochemical properties that significantly differ from those of the waters surrounding it, with lower salinity, and higher temperatures, concentrations of silicic acid and chlorophyll-a, and abundance of Synechococcus and Picoeukaryotes cells. Based on estimates of patch dimensions (~40 km width and ~25 m depth) and propagation speed (~0.09 m/sec), the volume flux associated with the patch is found to be in the order of 0.1 Sv. Our observations suggest that horizontal stirring by surface currents is likely to have an important impact on the ultra-oligotrophic Levantine basin ecosystem, through 1) transport of nutrients and coastal derived material, and 2) formation of local, dynamically isolated, niches. In addition, this work provides a satellite-based framework for planning and executing high resolution sampling strategies in the interface between coast and the open sea.

Efrati, Shai; Lehahn, Yoav; Rahav, Eyal; Kress, Nurit; Herut, Barak; Gertman, Isaac; Goldman, Ron; Ozer, Tal; Lazar, Michael; Heifetz, Eyal

2013-04-01

115

Intrusion of coastal waters into the pelagic Eastern Mediterranean: in situ and satellite-based characterization  

NASA Astrophysics Data System (ADS)

A combined dataset of near real time multi-satellite observations and in situ measurements from a high-resolution survey, is used for characterizing physical-biogeochemical properties of a patch stretching from the coast to the open sea in the Levantine basin of the Eastern Mediterranean. Spatial analysis of the combined dataset indicates that the patch is a semi-enclosed system, bounded within the mixed layer and separated from ambient waters by transport barriers induced by horizontal stirring. As such, the patch is characterized by physical-biogeochemical properties that significantly differ from those of the waters surrounding it, with lower salinity, higher temperatures, higher concentrations of silicic acid and chlorophyll a, and higher abundance of Synechococcus and Picoeukaryotes cells. Based on estimates of patch dimensions (~ 40 km width and ~ 25 m depth) and propagation speed (~ 0.09 m s-1), the volume flux associated with the patch is found to be in the order of 0.1 Sv. Our observations suggest that horizontal stirring by surface currents is likely to have an important impact on the ultra-oligotrophic Levantine basin ecosystem, through (1) transport of nutrients and coastal derived material, and (2) formation of local, dynamically isolated, niches. In addition, this work provides a satellite-based framework for planning and executing high resolution sampling strategies in the interface between coast and the open sea.

Efrati, S.; Lehahn, Y.; Rahav, E.; Kress, N.; Herut, B.; Gertman, I.; Goldman, R.; Ozer, T.; Lazar, M.; Heifetz, E.

2012-12-01

116

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

NASA Technical Reports Server (NTRS)

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

Jasinski, Michael; Eastman, Joseph; Borak, Jordan

2010-01-01

117

Development concerns for satellite-based air traffic control surveillance systems  

NASA Technical Reports Server (NTRS)

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.

Mcdonald, K. D.

1985-01-01

118

A Satellite-based High Resolution Precipitation Dataset for Studying Climate Extremes  

NASA Astrophysics Data System (ADS)

Analysis of climate extremes is an emerging research area that has recently captured increasing interest among scientists. Such studies, particularly in the changing climate, highly rely on long term high resolution global dataset. Satellite-based precipitation dataset are either not long-term enough for climate studies, or their coarse spatial and temporal resolutions limit detailed studies of climate extremes. The PERSIANN (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks) algorithm has been used to produce more than 30-year of daily precipitation data. Global longwave Infrared data from ISCCP (International Satellite Cloud Climatology Project) is the main input to the model. Global monthly GPCP precipitation data are used to adjust daily PERSIANN rainfall estimates. The adjusted daily PERSIANN is consistent to the GPCP rainfall at monthly scale. PERSIANN estimates (both before and after adjustment) are compared to both GPCP 2.5 degree monthly data for 1980-2009, and GPCP 1 degree daily data for 1997-2009. Additionally, daily data are compared to stage IV gauge adjusted radar data over the US. The tests showed considerable improvements in the reconstructed PERSIANN product. This PERSIANN global precipitation climate data record is available at daily temporal resolution and 0.25 degree geographic projection over 60S-60N for the period of 1979 to present time. This product can be very useful for extreme event analysis (intensity, frequency, and duration of floods & droughts) and water resources systems planning and management.

Ashouri, H.; Hsu, K.; Sorooshian, S.; Braithwaite, D.

2012-12-01

119

Interactive Web-Mapping System for Satellite Based Agricultural Applications in Bulgaria and Romania  

NASA Astrophysics Data System (ADS)

The interactive web-mapping system for satellite based agricultural application in Bulgaria and Romania was developed in the frame if the PROA GROB URO project. To achieve the project objectives a large amount of geospatial data was collected in the form of satellite images, maps and vector layers. Furthermore, the field measurements and descriptions were linked with the exact location where they have been made. There was a strong need to be able to analyse the data in an integrated way. Thus, a geodatabase was necessary with corresponding web-interface and applications providing data access to each of the partners. Using the newest Internet technologies a set of tools for creating and online publishing of geospatial data was successfully implemented The system components were developed entirely with standard compliant free and open source software like GDAL/OGR. GeoServer, OpenLayers and PostgreSQL+PostGIS. GMES recommendations and INSPIRE directive were taken into account when designing and implementing the system.

Craciunescu, Vasile; Stancalie, Gheorghe; Roumenina, Eugenia; Kazandjiev, Valentin; Jelev, Georgi; Filchev, Lachezar; Savin, Elena; Catana, Simona; Mihailescu, Denis

2012-06-01

120

Satellite-based detection of global urban heat-island temperature influence  

USGS Publications Warehouse

This study utilizes a satellite-based methodology to assess the urban heat-island influence during warm season months for over 4400 stations included in the Global Historical Climatology Network of climate stations. The methodology includes local and regional satellite retrievals of an indicator of the presence green photosynthetically active vegetation at and around the stations. The difference in local and regional samples of the normalized difference vegetation index (NDVI) is used to estimate differences in mean air temperature. Stations classified as urban averaged 0.90??C (N. Hemisphere) and 0.92??C (S. Hemisphere) warmer than the surrounding environment on the basis of the NDVI-derived temperature estimates. Additionally, stations classified as rural averaged 0.19??C (N. Hemisphere) and 0.16??C (S. Hemisphere) warmer than the surrounding environment. The NDVI-derived temperature estimates were found to be in reasonable agreement with temperature differences observed between climate stations. The results suggest that satellite-derived data sets can be used to estimate the urban heat-island temperature influence on a global basis and that a more detailed analysis of rural stations and their surrounding environment may be necessary to assure that temperature trends derived from assumed rural environments are not influenced by changes in land use/land cover. Copyright 2002 by the American Geophysical Union.

Gallo, K. P.; Adegoke, J. O.; Owen, T. W.; Elvidge, C. D.

2002-01-01

121

Satellite-based emission constraint for nitrogen oxides: Capability and uncertainty  

NASA Astrophysics Data System (ADS)

Vertical column densities (VCDs) of tropospheric nitrogen dioxide (NO2) retrieved from satellite remote sensing have been employed widely to constrain emissions of nitrogen oxides (NOx). A major strength of satellite-based emission constraint is analysis of emission trends and variability, while a crucial limitation is errors both in satellite NO2 data and in model simulations relating NOx emissions to NO2 columns. Through a series of studies, we have explored these aspects over China. We separate anthropogenic from natural sources of NOx by exploiting their different seasonality. We infer trends of NOx emissions in recent years and effects of a variety of socioeconomic events at different spatiotemporal scales including the general economic growth, global financial crisis, Chinese New Year, and Beijing Olympics. We further investigate the impact of growing NOx emissions on particulate matter (PM) pollution in China. As part of recent developments, we identify and correct errors in both satellite NO2 retrieval and model simulation that ultimately affect NOx emission constraint. We improve the treatments of aerosol optical effects, clouds and surface reflectance in the NO2 retrieval process, using as reference ground-based MAX-DOAS measurements to evaluate the improved retrieval results. We analyze the sensitivity of simulated NO2 to errors in the model representation of major meteorological and chemical processes with a subsequent correction of model bias. Future studies will implement these improvements to re-constrain NOx emissions.

Lin, J.; McElroy, M. B.; Boersma, F.; Nielsen, C.; Zhao, Y.; Lei, Y.; Liu, Y.; Zhang, Q.; Liu, Z.; Liu, H.; Mao, J.; Zhuang, G.; Roozendael, M.; Martin, R.; Wang, P.; Spurr, R. J.; Sneep, M.; Stammes, P.; Clemer, K.; Irie, H.

2013-12-01

122

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

NASA Astrophysics Data System (ADS)

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 preliminary work, this presentation will describe the benefits of modifying their original approach to incorporate more complex data assimilation filtering and land surface modeling methodologies. Particular emphasis is placed on alternative data assimilation approaches that allow for a more complex representation of stochastic rainfall errors. Modifications associated with improved 3-day rainfall accumulation estimates are then assembled to create the Soil Moisture Analysis Rainfall Tool (SMART). Results demonstrate that the SMART algorithm is superior to the Crow et al. (2009) baseline algorithm and capable of uniformly improving coarse-scale rainfall accumulation estimates with little risk of degradation. Comparisons with Tropical Rainfall Measurement Mission (TRMM) Precipitation Analysis (TMPA) multi-sensor data products suggest that the introduction of soil moisture information via SMART provides as much coarse-scale rainfall information as thermal satellite observations and more information than gauge-based corrections acquired in lightly-instrumented regions like North Africa

Crow, W. T.

2010-12-01

123

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

NASA Astrophysics Data System (ADS)

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.

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

2007-03-01

124

Satellite-Based Technologies in Use for Extreme Nocturnal Mountain Rescue Operations: a Synergetic Approach Applying Geophysical Principles  

NASA Astrophysics Data System (ADS)

Mountain-rescue operations require rapid response whilst also ensuring the security of the rescue teams. Rescuing people in a big rock-face is even more difficult if night or fog prevent sight. The paper presents a technical solution to optimally support, under these aggravated conditions, the location of the casualties and the navigation of the rescue team(s) in a rock-face from a coordination station. In doing so, standard components like a smartphones with GPS functionality, a data communication on a client-server basis and VR visualisation software have been adapted to the specific requirements. Remote support of the navigation in steep rocky terrain requires a highly accurate wall model which permits the local experts of the coordination station to dependably estimate geometry and structure of the rock along the rescue route and to convey necessary directives to the retrieval team. Based on terrestrial laser-scans from different locations, such a model has been generated for the mighty Dachstein South Face (Austria) and texturised with digital photographs. Over a twelve-month period, a transdisciplinary team of the Dresden University of Technology (Informatics, Electrical Engineering, Cartography) developed and integrated the various technical modules of the mountain-rescue support-system (digital rock-face model, optimised GPS data transmission between mobile device, server and client, data filtering, and dynamic visualisation component). In summer 2011 the proper functioning of the prototype was demonstrated in a rescue exercise under foggy dusk conditions.

Buchroithner, Manfred F.; Ehlert, Guido; Hetze, Bernd; Kohlschmidt, Horst; Prechtel, Nikolas

2014-06-01

125

Volcanic ash - Terrestrial versus extraterrestrial  

NASA Technical Reports Server (NTRS)

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.

Okeefe, J. A.

1976-01-01

126

Routing and Rate-Control for Coded Cooperation in a Satellite- Terrestrial Network.  

National Technical Information Service (NTIS)

We address the problem of high-throughput, delay-constrained communication over a satellite-terrestrial network where terrestrial node mobility leads to intermittent links. Due to the short time-scale of the link durations in this scenario, standard singl...

A. P. Worthen B. Shrader T. H. Shake

2011-01-01

127

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

NASA Astrophysics Data System (ADS)

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,

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

2010-05-01

128

Validation of satellite-based precipitation estimates over different African River Basins  

NASA Astrophysics Data System (ADS)

Satellite-based precipitation products have become increasingly available and accessible in near real-time, encouraging the scientific community increasingly to use these data to replace or supplement sparse ground observations. Six satellite-based rainfall estimates (SRFE), namely, CMORPH, RFE 2.0, TRMM 3B42, GPROF 6.0, PERSIANN, GSMaP-MKV, and one reanalysis product (ERA-interim) are validated against rain gauge data over four partly sparsely-gauged African river basins (Zambezi, Volta, Juba-Shabelle and Baro-Akobo). The objective is to provide the scientific community using SRFE as input data for hydro-meteorological applications an intercomparable validation study of these products over different hydro-climatological conditions in Africa. The validation focuses on the general ability of the SRFE products to reproduce daily and monthly rainfall and, particularly, on rainfall characteristics that are relevant to hydro-meteorological applications, such as, annual catchment totals, spatial distribution pattern within the river basin, seasonality of precipitation, number of rainy days per year, and timing and amount of heavy rainfall events. The accuracy of those products is assessed using a ground observation network, comprising of 203 stations with daily records between 2003 and 2006 (data coverage: <25, 25- 50, 50-75 and >75 % of data for 38, 13, 18 and 31 % of stations, respectively). Considering the time and space variability of the different rainfall characteristics as well as the conventional hydrological working units, the validation is done on three spatially-aggregated levels: point, subcatchment, and river basin. For the latter two the ground observations are interpolated using Kriging with External Drift, where the drift is defined as the terrain elevation. The performance is measured using standard statistical measures (MAE, RMSE, pBIAS, r, and NSeff) as well as visual inspection. The examined products showed depending on the spatially-aggregated level they have been analyzed: a) a good reproduction of dry periods, b) skills in reproducing precipitation over arid areas on a monthly basis, c) good representation of the spatial distribution pattern across the basins, d) difficulties in capturing the amount of precipitation on an event basis, and e) low detectability of heavy rainfall events over mountainous areas. Product-wise, GPROF 6.0 and GSMaP-MKV exhibited the poorest performance, which might be linked to the interpolation that was required due to the not complete daily coverage of the target areas and shortcomings in the algorithm selecting the correct rain profile, respectively. On the contrary, RFE 2.0 and TRMM 3B42 showed the highest potential in reproducing the inter-annual variability, the spatial and quantitative distribution, and the timing of rainfall events and, thus, may be recommendable as input for hydro-meteorological applications on a pan-African scale, such as monitoring and forecasting of floods and droughts.

Thiemig, V.; Rojas, R.; Levizzani, V.; De Roo, A.

2012-04-01

129

Satellite-based overshooting top detection methods and an analysis of correlated weather conditions  

NASA Astrophysics Data System (ADS)

The paper addresses two topics: the possibilities of satellite-based automatic detection of overshooting convective cloud tops and the connection between the overshootings and the occurrence of severe weather on the ground. Because the use of visible images is restricted to daytime, four detection methods based on the Meteosat Second Generation SEVIRI 10.8 ?m infra-red window channel and the absorption channels of water vapor (6.2 ?m), ozone (9.7 ?m) and carbon dioxide (13.4 ?m) in the form of brightness temperature differences were used. The theoretical background of all four methods is explained, and the detection results are compared with daytime high-resolution visible (HRV) satellite images to validate each method. Of the four tested methods, the best performance is found for the combination of brightness temperature differences 6.2-10.8 and 9.7-10.8 ?m, which are correlated to overshootings in HRV images in 80% of the cases. The second part of the research is focused on determining whether the appearance of the overshooting top, a manifestation of a very strong updraft in the cloud, can be connected to an abrupt change of certain weather elements on the ground. For all overshooting tops found by the above-mentioned combined method, automatic station data within the range of 0.1° and available hail observations within 0.2° were analyzed. The results show that the overshootings are connected to precipitation in 80% and to wind gusts in 70% of the cases; in contrast, a slightly lower correlation was found for temperature and humidity changes. Hail is observed in the vicinity of the overshooting in 38% of the cases.

Mikuš, Petra; Strelec Mahovi?, Nataša

2013-04-01

130

Categorizing natural disaster damage assessment using satellite-based geospatial techniques  

NASA Astrophysics Data System (ADS)

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.

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

2008-07-01

131

Global investigations of the satellite-based Fugro OmniSTAR HP service  

NASA Astrophysics Data System (ADS)

OmniSTAR is one of the world's leading suppliers of satellite-based augmentation services for onshore and offshore GNSS applications. OmniSTAR currently offers three services: VBS, HP and XP. OmniSTAR VBS is the code-based service, suitable for sub-metre positioning accuracy. The HP and XP services provide sub-decimetre accuracy, with the HP service based on a precise differential methodology and the XP service uses precise absolute positioning. The sub-decimetre HP and XP services both have distinctive convergence behaviour, and the positioning task is essentially a time-dependent process during which the accuracy of the estimated coordinates continuously improves over time. To validate the capabilities of the OmniSTAR services, and in particular the HP (High Performance) service, globally distributed measurement campaigns were performed. The results of these investigations confirm that the HP service satisfies its high accuracy specification, but only after a sufficient initialisation phase. Two kinds of disturbances can handicap HP operation: lack of GNSS observations and outages of the augmentation signal. The most serious kind of disturbance is the former. Within a few seconds the achieved convergence level is completely lost. Outages in the reception of augmentation data merely affect the relevant period of the outage - the accuracy during the outage is degraded. Only longer interruptions lead to a loss of the HP solution. When HP convergence is lost, the HP process has to be re-initialized. If there are known points (so-called “seed points”) available, a shortened “kick-start”-initialization is possible. With the aid of seed points it only takes a few minutes to restore convergence.

Pflugmacher, Andreas; Heister, Hansbert; Heunecke, Otto

2009-12-01

132

Advances in the Validation of Satellite-Based Maps of Volcanic Sulfur Dioxide Plumes  

NASA Astrophysics Data System (ADS)

The monitoring of volcanic gas emissions with gas cameras, spectrometer arrays, tethersondes, and UAVs presents new opportunities for the validation of satellite-based retrievals of gas concentrations. Gas cameras and spectrometer arrays provide instantaneous observations of the gas burden, or concentration along an optical path, over broad sections of a plume, similar to the observations acquired by nadir-viewing satellites. Tethersondes and UAVs provide us with direct measurements of the vertical profiles of gas concentrations within plumes. This presentation will focus on our current efforts to validate ASTER-based maps of sulfur dioxide plumes at Turrialba and Kilauea Volcanoes (located in Costa Rica and Hawaii, respectively). These volcanoes, which are the subjects of comprehensive monitoring programs, are challenging targets for thermal infrared (TIR) remote sensing due the warm and humid atmospheric conditions. The high spatial resolution of ASTER in the TIR (90 meters) allows us to map the plumes back to their source vents, but also requires us to pay close attention to the temperature and emissivity of the surfaces beneath the plumes. Our knowledge of the surface and atmospheric conditions is never perfect, and we employ interactive mapping techniques that allow us to evaluate the impact of these uncertainties on our estimates of plume composition. To accomplish this interactive mapping we have developed the Plume Tracker tool kit, which integrates retrieval procedures, visualization tools, and a customized version of the MODTRAN radiative transfer (RT) model under a single graphics user interface (GUI). We are in the process of porting the RT calculations to graphics processing units (GPUs) with the goal of achieving a 100-fold increase in the speed of computation relative to conventional CPU-based processing. We will report on our progress with this evolution of Plume Tracker. Portions of this research were conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.

Realmuto, V. J.; Berk, A.; Acharya, P. K.; Kennett, R.

2013-12-01

133

Categorizing natural disaster damage assessment using satellite-based geospatial techniques  

USGS Publications Warehouse

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.

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

2008-01-01

134

Evaluating Texas NOx emissions using satellite-based observations and model simulations  

NASA Astrophysics Data System (ADS)

Anthropogenic NOx is produced primarily from fossil fuel combustion by motor vehicles, power generation, and industrial processes. Satellite-based measurements have been used to assess NOx emission trends on regional to global spatial scales and daily to annual temporal scales. The small horizontal footprints of current satellite-borne instruments, including SCIAMACHY and OMI, can be used to detect NO2 resulting from NOx emitted by isolated point sources and metropolitan areas in the western US. In this study we examine NOx emissions in the state of Texas by comparing NO2 vertical columns retrieved from these satellite instruments to those predicted by a regional chemical-transport model. Comparisons of satellite-derived and model- calculated NO2 columns over US power plants, where in-stack emission monitoring is carried out, enables a critical evaluation of the key parameters leading to uncertainties in the satellite and model data products. By using the satellite retrieval algorithms and model configurations that produce the best agreement in NO2 columns over power plants in northeastern Texas and elsewhere in the western US, satellite-model comparisons of NO2 columns over Texas cities in turn allow urban NOx emission inventories to be assessed. This work focuses on two large Texas metropolitan areas: Dallas/Fort Worth, where NOx is emitted predominantly by mobile and area-wide sources; and Houston, which, like Dallas, has typical urban sources, but also contains large industrial point sources emitting significant amounts of NOx. Year-to-year and day-of- week changes in the satellite data are used to infer NOx emission trends from point and mobile sources and to evaluate the effectiveness of NOx controls on some of these sources.

Frost, G. J.; Kim, S.; McKeen, S.; Cooper, O.; Hsie, E.; Trainer, M.; Heckel, A.; Richter, A.; Burrows, J.; Gleason, J.

2008-12-01

135

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

NASA Astrophysics Data System (ADS)

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.

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

136

Satellite-based estimation of daily average net radiation under clear-sky conditions  

NASA Astrophysics Data System (ADS)

Daily average net radiation (DANR) is an important variable for estimating evapotranspiration from satellite data at regional scales, and is used for atmospheric and hydrologic modeling, as well as ecosystem management. A scheme is proposed to estimate the DANR over large heterogeneous areas under clear-sky conditions using only remotely sensed data. The method was designed to overcome the dependence of DANR estimates on ground data, and to map spatially consistent and reasonably distributed DANR, by using various land and atmospheric data products retrieved from MODIS (Moderate Resolution Imaging Spectroradiometer) data. An improved sinusoidal model was used to retrieve the diurnal variations of downward shortwave radiation using a single instantaneous value from satellites. The downward shortwave component of DANR was directly obtained from this instantaneous value, and the upward shortwave component was estimated using satellite-derived albedo products. Four observations of air temperature from MOD07_L2 and MYD07_L2 data products were used to derive the downward longwave component of DANR, while the upward longwave component was estimated using the land surface temperature (LST) and the surface emissivity from MOD11_L2. Compared to in situ observations at the cropland and grassland sites located in Tongyu, northern China, the root mean square error (RMSE) of DANR estimated for both sites under clear-sky conditions was 37 W m-2 and 40 W m-2, respectively. The errors in estimation of DANR were comparable to those from previous satellite-based methods. Our estimates can be used for studying the surface radiation balance and evapotranspiration.

Hou, Jiangtao; Jia, Gensuo; Zhao, Tianbao; Wang, Hesong; Tang, Bohui

2014-05-01

137

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

138

Scattering height estimation using scintillating Wide Area Augmentation System\\/Satellite Based Augmentation System and GPS satellite signals  

Microsoft Academic Search

An experiment to measure equatorial amplitude scintillations on the geostationary Wide Area Augmentation System (WAAS) Satellite Based Augmentation System (SBAS) signal was conducted in Cachoeira Paulista (22.70°S, 45.01°W geographic coordinates; ?17.74°N, 21.74°E geomagnetic coordinates), Brazil from December 2003 through February 2004. The purpose of this paper is to estimate the scattering height of the irregularities using the WAAS signal scintillations

A. P. Cerruti; B. M. Ledvina; P. M. Kintner

2006-01-01

139

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

140

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

Microsoft Academic Search

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

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

2010-01-01

141

Hazard assessment at Mount Etna using a hybrid lava flow inundation model and satellite-based land classification  

Microsoft Academic Search

Using a lava flow emplacement model and a satellite-based land cover classification, we produce a map to allow assessment\\u000a of the type and quantity of natural, agricultural and urban land cover at risk from lava flow invasion. The first step is\\u000a to produce lava effusion rate contours, i.e., lines linking distances down a volcano’s flank that a lava flow will

Andrew J. L. HarrisMassimiliano; Massimiliano Favalli; Robert Wright; Harold Garbeil

2011-01-01

142

Planning considerations for a national satellite-based TV system for educational services in a developing country  

NASA Astrophysics Data System (ADS)

Satellite-based educational TV (ETV) is considered in terms of the ability to address the educational needs of India as a case study of the policy, programming, and technological requirements of such a program. Pedagogic considerations broached include the language used, the mode of networking, duration, and scheduling. The components of an ETV system are set forth and include program production, facilities, manpower, transmission, utilization, and research.

Karnik, K. S.; Raman, N. K.

1991-10-01

143

Assessing Satellite-based and Aircraft-based Thermal Infrared Remote Sensing for Monitoring Pacific Northwest River Temperature  

NASA Astrophysics Data System (ADS)

One central issue affecting the health of native fish species in the Pacific Northwest is water temperature. In situ observation methods monitor point temperatures, while thermal infrared (TIR) remote sensing captures spatial variations. Satellite- based TIR sensors have the ability to view large regions in an instant. Four Pacific Northwest river reaches were selected to test the ability of both satellite-based and moderate resolution aircraft- based TIR remote sensing products to measure river temperatures. Images with resolutions of 5, 15, and 90 meters were compared with instream temperature observations to assess how along stream radiant temperatures are affected by resolution, reach width, and sensor platform. Where the stream reach can be resolved by the sensor, all sensors obtain water temperatures within ±2°C of instream observations. Along stream temperature variations of up to ±5°C were also observed. Trends were similar between two sets of TIR images taken several hours apart, indicating that the sensors are observing actual temperature patterns from the river surface. If sensor resolution is sufficient to obtain fully resolved water pixels in the river reach, accurate temperatures and spatial patterns can be observed. The current generation of satellite-based TIR sensors is, however, only able to resolve about 6 percent of all Washington reaches listed as thermally impaired.

Cherkauer, Keith A.; Burges, Stephen J.; Handcock, Rebecca N.; Kay, Jennifer E.; Kampf, Stephanie K.; Gillespie, Alan R.

2005-10-01

144

Towards a protocol for validating satellite-based Land Surface Temperature: Theoretical considerations  

NASA Astrophysics Data System (ADS)

Land Surface Temperature (LST) and emissivity are important parameters for environmental monitoring and earth system modelling. LST has been observed from space for several decades using a wide variety of satellite instruments with different characteristics, including both platforms in low-earth orbit and in geostationary orbit. This includes for example the series of Advanced Very High Resolution Radiometers (AVHRR) delivering a continuous thermal infrared (TIR) data stream since the early 1980s, the series of Along-Track Scanning Radiometers (ATSR) providing TIR data since 1991, and the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard NASA's Terra and Aqua platforms, providing data since the year 2000. In addition, the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard of the geostationary Meteosat satellites is now providing LST at unprecedented sub-hour frequency. The data record provided by such instruments is extremely valuable for a wide variety of applications, including climate change, land/atmosphere feedbacks, fire monitoring, modelling, land cover change, geology, crop- and water management. All of these applications, however, require a rigorous validation of the data in order to assess the product quality and the associated uncertainty. Here we report on recent work towards developing a protocol for validation of satellite-based Land Surface Temperature products. Four main validation categories are distinguished within the protocol: A) Comparison with in situ observations, B) Radiance-based validation, C) Inter-comparison with similar LST products, and D) Time-series analysis. Each category is further subdivided into several quality classes, which approximately reflect the validation accuracy that can be achieved by the different approaches, as well as the complexity involved with each method. Advice on best practices is given for methodology common to all categories. For each validation category, recommendations are further given with respect to specific methodology that has proven to be valuable for each approach. Selection criteria used for distinguishing the accuracy classes are established for each category and examples for the various categories and classes are provided. While the four validation categories introduced in the protocol exhibit varying levels of complexity and differ in terms of their resource demands, they are generally quite complementary, and a comprehensive LST validation will ideally entail certain elements from all four of them. The suggested validation protocol is a first attempt to provide a standardized framework for structuring the various LST validation approaches and will be further modified based on experiences and feedback from the LST validation community.

Schneider, Philipp; Ghent, Darren J.; Corlett, Gary C.; Prata, Fred; Remedios, John J.

2013-04-01

145

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

146

Phenology model from weather station meteorology does not predict satellite-based onset  

NASA Astrophysics Data System (ADS)

Seasonal temperature changes in temperate forests are known to trigger the start of spring growth, and both interannual and spatial variations in spring growth have been tied to climatic variability. Satellite data are finding increased use in regional and global phenological studies, but to date there have been few efforts to rigorously tie remotely sensed phenology to surface climate records. Where satellite records have been compared to broad-scale climate patterns, broadleaf deciduous forests have typically been characterized as a single functional type and differences between communities ignored. We used a simple two-parameter spring warming model to explore the relationship between interannual climate variability and satellite-based phenology in New England broadleaf temperate forests. We employed daily air temperature records between 2000 and 2005 from 171 NOAA meteorological stations to parameterize a simple spring warming model predicting the date of MODIS half-maximum greenness (spring onset). We find that the best model starts accumulating heating degree days (HDD) after March 20th and when average daily temperatures exceed 5°C. Critical heat sums to reach onset range from 150 to 300 degree-days, with increasing requirements southward and in coastal regions. In our findings, the spring warming model offers little improvement on the photoperiod null model (i.e. the average date of onset). However, differences between the relative goodness-of-fit of the spring warming model compared to the null (coined the 'climate sensitivity ratio', or CSR) displayed unexpected spatial coherency. The spatial variation in CSR appears to be related to differences in forest composition, with clear differences between northern (beech-maple-birch) and central (oak-hickory) hardwood forests. The two forest types may respond to climate differently, with disparate sensitivities to the minimum temperature initiating spring growth (3 and 6°C, respectively). We conclude that spatial location and species composition are critical factors which regulate the phenological response to climate. Regardless of model choice, satellite observations of temperate phenology cannot be effectively tied to climate without regard to community composition.

Fisher, J. I.; Richardson, A. D.; Mustard, J. F.

2006-12-01

147

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

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

148

Evaluation of Satellite Based Rainfall Estimation over Major River Basins in Africa  

NASA Astrophysics Data System (ADS)

Accuracy of satellite rainfall estimates are poorly known over Africa because of sparse ground based observations. We examined four widely used high resolution satellite products: the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) which is near-real-time (TMPA 3B42RT), the TMPA method post-real-time research version seven (TMPA 3B42v7), the Climate Prediction Center's morphing technique (CMORPH) and the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN). The main objective of the evaluation was to assess the performance of the satellite based estimates in capturing the overall climatological blueprints of rainfall over Africa at various spatio-temporal scale, and inter-comparison of the estimates across the various climatological regimes in Africa. In the tropical, complex terrain region of East Africa, the results show poor skills of satellite rainfall in capturing elevation dependent rainfall structure; microwave based CMORPH and 3B42RT estimates provide relatively accurate estimate of rainfall in high elevation areas but showed excessive overestimation in low elevation, and merging GTS-based rain gauges with the Satellite-Only products deteriorated the accuracy of rainfall estimation in high elevation areas of the Blue Nile. In this study we present the findings over seven other large and sparsely gauged river basins: Sengal (419,659 km2), Jubba (497,655 km2), Volta (407,093 km2), Ogooue (223,656 km2), Ubangi (613,202 km2) Okavango (721,277 km2) and Kasai (925,172 km2) river basins representing different topography and climate system between 250 N and 250 S. The accuracy of those products is assessed using a ground based GPCC datasets and through inter-comparision among the products between 2003 -2011 at a resolution of 25 km by 25-km and 3 hr data. Based on these datasets we present annual, seasonal and monthly spatial structure of rainfall in terms of depth, rainy days and other standard statistical measures (Pearson's Correlation, %Bias, MAE and RMSE). The results demonstrate how different are the various estimates, which estimation algorithms show minimum error and in which region. The results could shade light on the applications of satellite rainfall estimates for water resource management, agriculture, water and food security studies and climate change over continental Africa.nnual rainfall structure using satellite rainfall estimates in Blue Nile Basin

Bitew, M. M.; Gebremichael, M.

2012-12-01

149

Assessment of Satellite-based Precipitation Products (TRMM) in Hydrologic Modeling: Case Studies from Northern Morocco  

NASA Astrophysics Data System (ADS)

Precipitation is the most important forcing parameter in hydrological modeling, yet it is largely unknown in the arid Middle East. We assessed the magnitude, probability of detection, and false alarm rates of various rainfall satellite products (e.g., TRMM, RFE2.0) compared to in situ gauge data (~79 stations) across the Our Er Rbia, Sebou, and Melouya Watersheds in Northern Morocco. Precipitation over the area is relatively high with an average of ~400mm/year according to TRMM (1998-2008). The existing gauges indicate that the average annual precipitation across the Tadla and Coastal Plains region is 260mm/year and 390mm/year across the Atlas Mountains. Following the assessment of satellite products against in situ gauge data, we evaluated the effects (e.g., runoff and recharge amounts) of using satellite driven hydrologic models using SWAT. Specifically, we performed a four-fold exercise: (1) The first stage focused on the analysis of the rainfall products; (2) the second stage involved the construction of a rainfall-runoff model using gauge data; (3) the third stage entailed the calibration of the model against flow gauges and/or dams storage variability, and (4) model simulation using satellite based rainfall products using the calibrated parameters from the initial simulation. Results suggest the TRMM V7 has a much better correlation with the field data over the Oum Er Rbia watershed. The Correlation E (Nash-Suncliffe coefficient) has a positive value of 0.5, while the correlation coefficient of TRMM V6 vs. gauges data is a negative value of -0.25. This first order evaluation of the TRMM V7 shows the new algorithm has partially overcame the underestimation effect in the semi-arid environments. However, more research needs to be done to increase the usability of TRMM V7 in hydrologic models. Low correlations are most likely a result of the following: (1) snow at the high elevations in the Oum Er Rbia watershed, (2) the ocean effect on TRMM measurements along the coast, and (3) the averaging of many local rain-fall events within an area of 0.25° to 0.25°. The potential for using publicly available remote sensing datasets in lieu of field gauges in data sparse and inaccessible regions is clear. This will address one of the major difficulties facing hydrologists while constructing representative rainfall runoff models in the absence of field data as it is the case of most of North African watersheds.

EL kadiri, R.; Milewski, A.; Durham, M.

2012-12-01

150

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

PubMed Central

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.

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

2014-01-01

151

Satellite-based Assessment of Climate Controls on US Burned Area  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

152

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

SciTech Connect

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.

Mitchell, David L

2009-10-14

153

Toward a satellite-based observation of atmospheric heat source over land  

NASA Astrophysics Data System (ADS)

heat source is concerned in global circulation and monsoon studies. Its accurate quantification by conventional methods needs high-quality gridded meteorological data or energy flux data, which are usually not available in most regions. In this study, we present a simple method to quantify apparent heat source over land. The required inputs are net radiation at the top of atmosphere, terrestrial water storage change, river runoff, and ground heat flux. The former two can be directly observed by satellites, the runoff is measured for major rivers in the world and is to be measured by an upcoming satellite mission, and the ground heat flux is a small term, which can be estimated by satellite remote sensing or land surface modeling. Two applications of this method demonstrate its potential in quantifying the variations of heat source over land at global and regional scales.

Yang, Kun; Wu, Hui; Chen, Yingying; Qin, Jun; Wang, Lei

2014-03-01

154

Antarctic terrestrial ecosystems  

SciTech Connect

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.

Walton, D.W.H.

1987-01-01

155

Solar terrestrial observatory  

NASA Technical Reports Server (NTRS)

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.

1981-01-01

156

A comprehensive design and performance analysis of low Earth orbit satellite quantum communication  

NASA Astrophysics Data System (ADS)

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 analyse the performance of a low Earth orbit 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.

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

2013-02-01

157

Terrestrial Planet Atmospheres and Biosignatures  

NASA Astrophysics Data System (ADS)

The search for terrestrial exoplanets - rocky worlds in orbit around stars other than the Sun - is one of humanity's most exciting science goals. The discovery of super Earths, terrestrial planets more massive than Earth, has opened a new era in exoplanet science, confirming the basic idea that our solar system is not the only planetary system to harbor terrestrial planets. Terrestrial exoplanets will expand planetary diversity, with masses and compositions likely very different from those found in our solar system. Most significantly, terrestrial exoplanets have the potential to host habitable environments on or below their solid surfaces, and are the most likely places beyond our solar system to search for signs of life. In the coming decades, instrumentation will be developed to expand our census of terrestrial exoplanets and directly characterize the atmospheres and biosignatures of these worlds. In the meantime, scientific progress in this field is made via extensive photochemical, climate, and radiative transfer modeling of terrestrial planetary environments together with remote sensing studies of solar system terrestrial planets, including Earth. This chapter provides an overview of terrestrial exoplanet atmosphere modeling techniques, a review of the scientific advances to date, and a discussion of outstanding questions and future directions.

Meadows, V.; Seager, S.

158

Solar structure and terrestrial weather  

NASA Technical Reports Server (NTRS)

The possibility that solar activity has discernible effects on terrestrial weather is considered. Research involving correlation of weather conditions with solar and geomagnetic activity is discussed.

Wilcox, J. M.

1976-01-01

159

Low Earth Orbit satellite/terrestrial mobile service compatibility  

NASA Technical Reports Server (NTRS)

Currently the geostationary type of satellite is the only one used to provide commercial mobile-satellite communication services. Low earth orbit (LEO) satellite systems are now being proposed as a future alternative. By the implementation of LEO satellite systems, predicted at between 5 and 8 years time, mobile space/terrestrial technology will have progressed to the third generation stage of development. This paper considers the system issues that will need to be addressed when developing a dual mode terminal, enabling access to both terrestrial and LEO satellite systems.

Sheriff, Ray E.; Gardiner, John G.

1993-01-01

160

Asia-MIP: Multi Model-data Synthesis of Terrestrial Carbon Cycles in Asia  

NASA Astrophysics Data System (ADS)

Asia, which is characterized by monsoon climate and intense human activities, is one of the prominent understudied regions in terms of terrestrial carbon budgets and mechanisms of carbon exchange. To better understand terrestrial carbon cycle in Asia, we initiated multi-model and data intercomparison project in Asia (Asia-MIP). We analyzed outputs from multiple approaches: satellite-based observations (AVHRR and MODIS) and related products, empirically upscaled estimations (Support Vector Regression) using eddy-covariance observation network in Asia (AsiaFlux, CarboEastAsia, FLUXNET), ~10 terrestrial biosphere models (e.g. BEAMS, Biome-BGC, LPJ, SEIB-DGVM, TRIFFID, VISIT models), and atmospheric inversion analysis (e.g. TransCom models). We focused on the two difference temporal coverage: long-term (30 years; 1982-2011) and decadal (10 years; 2001-2010; data intensive period) scales. The regions of covering Siberia, Far East Asia, East Asia, Southeast Asia and South Asia (60-80E, 10S-80N), was analyzed in this study for assessing the magnitudes, interannual variability, and key driving factors of carbon cycles. We will report the progress of synthesis effort to quantify terrestrial carbon budget in Asia. First, we analyzed the recent trends in Gross Primary Productivities (GPP) using satellite-based observation (AVHRR) and multiple terrestrial biosphere models. We found both model outputs and satellite-based observation consistently show an increasing trend in GPP in most of the regions in Asia. Mechanisms of the GPP increase were analyzed using models, and changes in temperature and precipitation play dominant roles in GPP increase in boreal and temperate regions, whereas changes in atmospheric CO2 and precipitation are important in tropical regions. However, their relative contributions were different. Second, in the decadal analysis (2001-2010), we found that the negative GPP and carbon uptake anomalies in 2003 summer in Far East Asia is one of the largest anomalies with high consistency among methods from 2001 to 2010 period. The model analysis showed that these anomalies were produced by different climate factors among the models. Therefore, we conclude that inconsistency of model sensitivity to meteorological anomalies is an important issue to be improved in future. Acknowledgement The study is financially supported by the Environment Research and Technology Development Fund (RFa-1201) of the Ministry of the Environment of Japan and JSPS KAKENHI Grant Number 25281003.

Ichii, K.; Kondo, M.; Ito, A.; Kang, M.; Sasai, T.; SATO, H.; Ueyama, M.; Kobayashi, H.; Saigusa, N.; Kim, J.

2013-12-01

161

Satellite-based solar radiation mapping over complex terrain: Validation in the Alps and possible improvements  

NASA Astrophysics Data System (ADS)

Solar radiation is an essential variable for applications such as the climate monitoring or the planning of systems exploiting solar energy. This study presents a validation of surface irradiance derived from MSG (Meteosat second generation) satellite data with an extended version of the Heliosat algorithm [3] in the Alps. The algorithm implemented by MeteoSwiss is based on the clear-sky LUT (look up table) approach proposed by Müller et al., 2009 [2], and a probabilistic cloud mask adapted to MSG from the scheme of Khlopenkov and Trishchenko, 2007 [1]. The validation study focuses on the accuracy of the diffuse/direct components of irradiance and suggests possible improvements. We performed a detailed analysis at three locations, i.e. two Alpine sites - Bolzano (IT), at low altitude, and Davos (CH), at high altitude - and Payerne (CH), in the Swiss Plateau, comparing the hourly, daily, monthly and seasonal bias of the satellite estimation against ground measurements. Results indicate, in terms of MBD (mean bias deviation) and MAD (mean absolute deviation), that the algorithm reproduces precisely the yearly cycle, especially for global irradiance (MBD between -1 and 6 W/m2, MAD between 3 and 13 W/m2). On a daily time scale the all-sky MAD is below 15 W/m2 for all the components of radiation, while it is above 40 W/m2 at the hourly scale. In the mean daily cycle diffuse irradiance is overestimated (10-20 W/m2) for the two stations based on a valley floor, while it is underestimated in the other one. We noticed that cloud free conditions are affected by the biggest absolute error, especially in summer. We therefore investigated the role of aerosols in the clear-sky uncertainty. By including in the radiative transfer model adopted for the simulations either ground or satellite daily atmospheric input on aerosol and water vapor, the estimation of the hourly averages of diffuse radiation improves significantly (MAD < 10 W/m2) compared to the satellite estimate. Consequently it is recommended to include in the clear-sky model more accurate input than the currently used monthly climatologies of aerosol and the operational 1 day forecast of column water vapor amount from the ECMWF model ouptut. References [1] K. V. Khlopenkov And A. P. Trishchenko, "SPARC: New Cloud, Snow, and Cloud Shadow Detection Scheme for Historical 1-km AVHHR Data over Canada", Journal of Atmospheric and Oceanic Technology, 24, pp. 322-343, 2007. [2] R.W. Müller, C. Matsoukas, A. Gratzki, H.D. Behr, R. Hollmann. "The CM-SAF operational scheme for the satellite based retrieval of solar surface irradiance - A LUT based eigenvector hybrid approach", Remote Sensing of Environment, 113, pp.1012-1024, 2009. [3] R. Stöckli (in prep.). "Supplementing Heliosat for physically-based surface radiation retrieval in complex terrain."

Castelli, Mariapina; Stoeckli, Reto; Tetzlaff, Anke; Ernst Wagner, Jochen; Zardi, Dino; Petitta, Marcello

2013-04-01

162

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

163

NASA's Commercial Communication Technology Program  

NASA Technical Reports Server (NTRS)

Various issues associated with "NASA's Commercial Communication Technology Program" are presented in viewgraph form. Specific topics include: 1) Coordination/Integration of government program; 2) Achievement of seamless interoperable satellite and terrestrial networks; 3) Establishment of program to enhance Satcom professional and technical workforce; 4) Precompetitive technology development; and 5) Effective utilization of spectrum and orbit assets.

Bagwell, James W.

1998-01-01

164

Large-scale atmospheric carbon and surface water dynamics inferred from satellite-based observations  

NASA Astrophysics Data System (ADS)

The sensitivity of Earth's wetlands to observed shifts in global precipitation and temperature patterns and their ability to produce large quantities of climate-active gases are key global change questions. Surface inundation is a crucial state variable that affects the rate of land-atmosphere carbon exchange and the partitioning of carbon between CO2 and CH4. Ground observation networks of large-scale inundation patterns are sparse because they require large fiscal, technological and human resources. Thus, satellite remote sensing products for global inundation dynamics, as well as total water storage and atmospheric carbon, can provide a complete synoptic view of past and current carbon - surface water dynamics over large areas that otherwise could not be assessed. We present results from a correlative analysis between spaceborne measurements of CO2 and CH4 as observed by SCIAMACHY and AIRS, water storage (derived from gravity anomalies provided by NASA's GRACE mission), and inundated water fraction derived from a combination of active and passive microwave remote sensing datasets. A general assessment is conducted globally, and further time-series analysis is focused on four regions of interest: North Amazon, Congo, Ob, and Ganges-Brahmaputra river basins. This analysis was supported by a grant from the NASA Terrestrial Ecology Program and the development of the inundation datasets was supported by the NASA MEaSUREs program.

Jensen, K.; McDonald, K. C.; Krakauer, N.; Schroeder, R.

2013-12-01

165

Satellite-based Estimates of Surface and Groundwater Storage Variations in the Amazon Basin  

NASA Astrophysics Data System (ADS)

The Amazon river basin has been recently affected by extreme climatic events, such as the exceptional drought of 2005, with signi?cant impacts on human activities and ecosystems. In spite of the importance of monitoring freshwater stored and moving in such large river basins, only scarce measurements of river stages and discharges are available and the signatures of extreme drought conditions on surface freshwater dynamics at the basin scale are still poorly known. Here we use continuous multisatellite observations of inundation extent and water levels between 2003 and 2007 to monitor monthly variations of surface water storage at the basin scale. During the 2005 drought, the amount of water stored in the river and ?oodplains of the Amazon basin was ˜130 km3 (˜70%) below its 2003-7 average. This represents almost a half of the anomaly of minimum terrestrial water stored in the basin as estimated using the Gravity Recovery and Climate Experiment (GRACE) data. Water stored in the aquifer is isolated from the total water storage measured by GRACE by removing the contributions of both the surface reservoir, previously derived from satellite imagery and radar altimetry, and the root zone reservoir simulated by hydrological models such as LaD and WGHM. The spatio-temporal variations of surface and groundwater reservoirs are compared to other hydrological datasets (i.e., rainfall from TRMM or GPCP, discharges, ...) and analyzed at subbasin scale in the context of the climate variability and recent extreme events such as the drought of 2005.

Frappart, Frédéric; Papa, Fabrice; Santos da Silva, Joecila; Ramillien, Guillaume; Prigent, Catherine; Seyler, Frédérique; Calmant, Stéphane

2013-04-01

166

Satellite-based climate information within the WMO RA VI Regional Climate Centre on Climate Monitoring  

NASA Astrophysics Data System (ADS)

The World Meteorological Organization (WMO) established Regional Climate Centres (RCCs) around the world to create science-based climate information on a regional scale within the Global Framework for Climate Services (GFCS). The paper introduces the satellite component of the WMO Regional Climate Centre on Climate Monitoring (RCC-CM) for Europe and the Middle East. The RCC-CM product portfolio is based on essential climate variables (ECVs) as defined by the Global Climate Observing System (GCOS), spanning the atmospheric (radiation, clouds, water vapour) and terrestrial domains (snow cover, soil moisture). In the first part, the input data sets are briefly described, which are provided by the EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites) Satellite Application Facilities (SAF), in particular CM SAF, and by the ESA (European Space Agency) Climate Change Initiative (CCI). In the second part, the derived RCC-CM products are presented, which are divided into two groups: (i) operational monitoring products (e.g. monthly means and anomalies) based on near-real-time environmental data records (EDRs) and (ii) climate information records (e.g. climatologies, time series, trend maps) based on long-term thematic climate data records (TCDRs) with adequate stability, accuracy and homogeneity. The products are provided as maps, statistical plots and gridded data, which are made available through the RCC-CM website (www.dwd.de/rcc-cm).

Obregón, A.; Nitsche, H.; Körber, M.; Kreis, A.; Bissolli, P.; Friedrich, K.; Rösner, S.

2014-05-01

167

Benchmarking terrestrial biospheric models against CO2 observations from GOSAT  

NASA Astrophysics Data System (ADS)

There is a large degree of uncertainty in terrestrial biospheric model (TBM) representation of both the magnitude and spatial distribution of carbon sources and sinks on the land surface. The lack of direct observations of land-atmosphere carbon exchange at the resolution of model estimates makes it difficult to assess the strengths and weaknesses of various modeling approaches in terms of their ability to represent the terrestrial carbon cycle. Atmospheric CO2 observations, however, provide an integrated view of surface sources and sinks of carbon, thus providing a potential powerful observational constraint for TBMs. Using the model results from the North American Carbon Program (NACP) Multi-scale synthesis and Terrestrial Model Intercomparison Project (MsTMIP) and the framework of NASA's Carbon Monitoring System (CMS) we assess the consistency of TBMs with satellite-based observations of atmospheric CO2. The MsTMIP TBM surface flux estimates, together with fossil fuel, air-sea fluxes, and biomass burning inventories, are coupled with the GEOS-Chem atmospheric transport model within CMS to generate the corresponding atmospheric CO2 signals. These signals are then pressure-averaged and directly compared with dry air column-averaged mole fractions of CO2 (?CO2) from the Greenhouse Gases Observing Satellite (GOSAT). Using model selection and multi-linear regression, we assess which model, or ensemble of models, best explain the ?CO2 observations. By weighting each model based on its consistency with GOSAT ?CO2 we identify the optimal weight for each individual model in a weighted multi-model ensemble. The inferred weights derived from the regression can help inform understanding of the relationship between surface flux representations and atmospheric CO2 measurements and can be linked back to process representation within the models themselves. Thus, comparing TBM estimates to atmospheric CO2 observations not only serves as an additional benchmark of model performance, but the results from these comparisons can also be used to aid in model development and improvement.

Swetish, J. B.; Huntzinger, D. N.; Michalak, A. M.; Schwalm, C. R.; Fisher, J. B.; Liu, J.; Bowman, K. W.

2013-12-01

168

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

National Technical Information Service (NTIS)

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 R...

B. A. Cosgrove C. D. Peters-Lidard G. Riggs J. Borak J. Geiger L. G. D. DeGoncalves M. Smith N. Mizukami S. Yatheendradas S. V. Kumar V. Koren Z. Cui

2012-01-01

169

Tidally Heated Terrestrial Exoplanets  

NASA Astrophysics Data System (ADS)

This work models the surface and internal temperatures for hypothetical terrestrial planets in situations involving extreme tidal heating. The feasibility of such planets is evaluated in terms of the orbital perturbations that may give rise to them, their required proximity to a hoststar, and the potential for the input tidal heating to cause significant partial melting of the mantle. Trapping terrestrial planets into 2:1 resonances with migrating Hot Jupiters is considered as a reasonable way for Earth-like worlds to both maintain high eccentricities and to move to short enough orbital periods (1-20 days) for extreme tidal heating to occur. Secular resonance and secular orbital perturbations may support moderate tidal heating at a low equilibrium eccentricity. At orbital periods below 10-30 days, with eccentricities from 0.01 to 0.1, tidal heat may greatly exceed radiogenic heat production. It is unlikely to exceed insolation, except when orbiting very low luminosity hosts, and thus will have limited surface temperature expression. Observations of such bodies many not be able to detect tidal surface enhancements given a few percent uncertainty in albedo, except on the nightside of spin synchronous airless objects. Otherwise detection may occur via spectral detection of hotspots or high volcanic gas concentrations including sulfur dioxide and hydrogen sulfide. The most extreme cases may be able to produce magma oceans, or magma slush mantles with up to 40-60% melt fractions. Tides may alter the habitable zones for smaller red dwarf stars, but are generally detrimental. Multiple viscoelastic models, including the Maxwell, Voigt-Kelvin, Standard Anelastic Solid, and Burgers rheologies are explored and applied to objects such as Io and the super-Earth planet GJ 876d. The complex valued Love number for the Burgers rheology is derived and found to be a useful improvement when modeling the low temperature behavior of tidal bodies, particularly during low eccentricity excursions. Viscoelastic solutions for GJ 876d are typical of extreme short period high eccentricity objects with tidal-convectiveequilibrium heat rates between ˜10,000 to 500,000 terawatts.

Henning, Wade Garrett

170

High power optical amplifier enable 1550 nm terrestrial free-space optical data-link operating @ 10 Gb\\/s  

Microsoft Academic Search

Optical amplifiers are an enabling technology for free space laser communications. Transmission of four multiplexed 2.5 Gbps channels at 1550 nm over a 4.4 km terrestrial link is described and modeled

P. F. Szajowski; G. Nykolak; J. J. Auborn; H. M. Presby; G. E. Tourgee

1999-01-01

171

Ground jammer localization with two satellites based on the fusion of multiple parameters  

NASA Astrophysics Data System (ADS)

Space Situational Awareness (SSA) requires the ability for secure communication of information and sensing of objects in space, reliable estimation on ground information from space, and command and control of sensor resources to space. Inherent in the secure, reliable, and robust coordination with space assets is the ability to monitor and detect jammer activities. This paper presents a ground jammer localization method by fusing multiple parameters (including time difference of arrival (TDOA), frequency and direction of arrival (DOA)) collected using two satellites via an extended Kalman filter (EKF) with a two-step initialization process. The first step uses DOA fusion and the second step uses DOA-TDOA fusion. The two-step initialization guarantees the convergence of the EKF and therefore the high localization accuracy. The simulation shows that the ground jammer can be localized using the space assets within 100 meters, which is accurate enough for many applications.

Wang, Zhonghai; Pham, Khanh; Blasch, Erik; Chen, Genshe

2011-05-01

172

Reaping the space investment. [Shuttle era geosynchronous satellite based technological trends  

NASA Technical Reports Server (NTRS)

By 1999 operational space systems will be implemented routinely on a worldwide scale in many areas vital to human survival and life quality. Geosynchronous-based monitoring and observation will be extensively used. The Shuttle era will bring in the capability to allow monitoring and identifying pollution sources which fail to stay within required limits. Remotely sensed data over land masses will provide needed facts on renewable and nonrenewable earth resources. New instruments and techniques will have been developed to provide geologists with clues to the declining number of deposits of fuels and minerals. Also, practical methods for predicting earthquakes will have been elaborated by 1999. Communications will see implementation of many of the technological goals of 1978.

Calio, A. J.

1979-01-01

173

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

NASA Technical Reports Server (NTRS)

Monitoring of the global distribution of tropospheric ozone (O3) is desirable for enhanced scientific understanding as well as to potentially lessen the ill-health impacts associated with exposure to elevated concentrations in the lower atmosphere. Such a capability can be achieved using a satellite-based device making high spectral resolution measurements with high signal-to-noise ratios; this would enable observation in the pressure-broadened wings of strong O3 lines while minimizing the impact of undesirable signal contributions associated with, for example, the terrestrial surface, interfering species, and clouds. The Fabry-Perot Interferometer (FPI) provides high spectral resolution and high throughput capabilities that are essential for this measurement task. Through proper selection of channel spectral regions, the FPI optimized for tropospheric O3 measurements can simultaneously observe a stratospheric component and thus the total O3 column abundance. Decreasing stratospheric O3 concentrations may lead to an increase in biologically harmful solar ultraviolet radiation reaching the earth's surface, which is detrimental to health. In this research, a conceptual instrument design to achieve the desired measurement has been formulated. This involves a double-etalon fixed-gap series configuration FPI along with an ultra-narrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately .068 cm(exp -1). A spectral region of about 1 cm(exp -1) wide centered at 1054.73 cm(exp -1) within the strong 9.6 micron ozone infrared band is sampled with 24 spectral channels. Other design characteristics include operation from a nadir-viewing satellite configuration utilizing a 9 inch (diameter) telescope and achieving horizontal spatial resolution with a 50 km nadir footprint. A retrieval technique has been implemented and is demonstrated for a tropical atmosphere possessing enhanced tropospheric ozone amounts. An error analysis assessing the impact on retrieved O3 amounts of the most significant uncertainties associated with this particular measurement has been performed for several different types of atmospheres. Results show the proposed instrumentation to enable a good measurement of absolute ozone amounts and an even better determination of relative changes, with a range of accuracy to within 7.55 to 20.6 percent for integrated tropospheric amounts (and 1.99 to 4.02 percent for total O3 column abundance) and a corresponding range in precision to within 7.73 to 10.4 percent (and 3.30 to 3.95 percent for total O3 column abundance), for the atmospheric conditions considered.

Larar, Allen Maurice

1993-01-01

174

Superconductors and cryogenics for future communication systems  

Microsoft Academic Search

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

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

175

Space network support for lunar communications  

NASA Technical Reports Server (NTRS)

The space network can provide high data rate lunar communications as an alternative or adjunct to an expansion of the deep space network. Use of a space-based system can provide continuous coverage for lunar users and reduce terrestrial communication costs by delivering data directly to a single domestic location. Adapting the space network for lunar communications support would also maximize the use of the existing and planned space network and Space Station infrastructure. Several alternative architectures are evaluated.

Jordan, Michael A.

1991-01-01

176

Mobile radio alternative systems study. Volume 2: Terrestrial. [rural areas  

NASA Technical Reports Server (NTRS)

Terrestrial systems for satisfying the markets for mobile radio services in non-urban areas of the United States in the years from 185 to 2000 were investigated. Present day mobile communication technologies, systems and equipment are described for background in evaluating the concepts generated. Average propagation ranges are calculated for terrestrial installations in each of seven physiographic areas of the contiguous states to determine the number of installations that would be required for nationwide coverage. Four system concepts are defined and analyzed to determine how well terrestrial systems can fulfill the requirements at acceptable costs. Nationwide dispatch, telephone and data services would require terrestrial installations in many locations where they would be used infrequently and would not recover their investment. Access to a roaming vehicle requires that the vehicle location be known within the range limit of the terrestrial installation in which the vehicle is present at the time of the call. Access to that installation must be made through the public switched telephone network, usually involving a long-distance toll charge, and requiring costly means to track or locate the vehicle as it moved through the network of installations.

Cromwell, N.; Lester, H. L.; Anderson, R. E.

1983-01-01

177

Emergency Communication for Electric Power System Based on Airship  

Microsoft Academic Search

The problems facing the communication for electric power system safety were recently highlighted by ice disaster in southern China and Wenchuan earthquake. The existing communication systems in the Yunnan power grid are far from adequate. Terrestrial networks are disabled by serious natural disaster. Satellite communication network is deficient in bandwidth, and has high propagation delay, which cannot satisfy the demand

Ming Huang; Jiang Yu; Jinsong Hu; Ling Zhao; Rong Zong

2009-01-01

178

Using a satellite-based potential ET product for operational hydrologic forecasting  

NASA Astrophysics Data System (ADS)

Accurate modeling of the surface water balance is critical to forecasting streamflow, flood events and water supply. Land use and climate changes are significantly altering all components of the terrestrial hydrologic cycle, including evapotranspiration fluxes. Current National Weather Service (NWS) hydrologic forecasting methods use potential evapotranspiration (PET) inputs derived from historical pan evaporation observations that remain static from year-to-year. These climatologies are based on data that date back several decades. A more current and dynamic method for estimating PET is needed to assure that model inputs are reflective of rapid and continual changes in the physical system. In the past decade, remote sensing data, specifically from the NASA Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua satellites, have become readily available and MODIS products are playing an increasingly vital role in various Earth system models. Concurrently, adoption of a more robust forecast system by the NWS is in early operational stages. This new forecast system will ultimately be able to accommodate dynamic data streams, such as data derived from MODIS products, that have the potential to advance the science of hydrologic forecasting. In this study, a PET algorithm that uses only MODIS-based inputs and the Priestley-Taylor formulation is used in deriving daily PET (MODIS-PET) for six basins under the jurisdiction of the NWS North Central River Forecast Center (NCRFC). Thirteen MODIS products are used to estimate daily PET values from May through September at 500m resolution. In the first step of the study, a basin-averaged (lumped) mean daily PET value is generated and a new PET climatology curve based on an eight year average (2003-2010) is computed for input into NWS forecast models. Overall, streamflow simulation performed better once the model had been recalibrated using the new MODIS-PET climatology curve. Simulations are more reflective of observed streamflow during recession periods, especially early in the growing season; however, simulations during peak flow events, on average, tended to perform worse. In the second step, the daily PET time series is input directly into the forecasting models to determine how daily varying PET impacts simulations.

Bowman, A.; Franz, K. J.; Hogue, T. S.; Kim, J.; Deweese, M. M.

2012-12-01

179

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

180

Correcting rainfall using satellite-based surface soil moisture retrievals: The Soil Moisture Analysis Rainfall Tool (SMART)  

NASA Astrophysics Data System (ADS)

Recently, 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 incorporate more complex data assimilation and land surface modeling methodologies. Specific modifications improving rainfall estimates are assembled into the Soil Moisture Analysis Rainfall Tool (SMART), and the resulting algorithm is applied outside the contiguous United States for the first time, with an emphasis on West African sites instrumented as part of the African Monsoon Multidisciplinary Analysis experiment. Results demonstrate that the SMART algorithm is superior to the Crow et al. baseline approach and is capable of broadly improving coarse-scale rainfall accumulations measurements with low risk of degradation. Comparisons with existing multisensor, satellite-based precipitation data products suggest that the introduction of soil moisture information from the Advanced Microwave Scanning Radiometer via SMART provides as much coarse-scale (3 day, 1°) rainfall accumulation information as thermal infrared satellite observations and more information than monthly rain gauge observations in poorly instrumented regions.

Crow, W. T.; van den Berg, M. J.; Huffman, G. J.; Pellarin, T.

2011-08-01

181

Solar-terrestrial influence  

NASA Astrophysics Data System (ADS)

Solar phenomena are examined to assess the extent of knowledge of the effect of the sun on the earth. The earth is gravitationally coupled to the sun, imbedded in the solar corona and thereby subject to particle bombardment and the influence of the solar magnetic field, and is directly illuminated by the sun at a rate of 1.367 kW/sq m. The coronal density is 10 particles/cu cm at the earth's distance from the sun, and the solar magnetic field is 1/10,000 what it is at the solar surface. Particle bombardment from the sun causes auroral displays, while other particles are diverted by the terrestrial magnetosphere and form a bow shock. Incoming solar protons dissociate NO in the upper atmosphere and form ozone. The ability of the earth's atmosphere at any time to absorb the total incoming solar radiation is a determining factor in the heating of the atmosphere. The heated atmosphere expands and may slow down satellites in LEO, while no precise modelling has yet been accomplished for the relationship between heating and climatic variations.

Bonnet, R. M.

182

Utility terrestrial biodiversity issues  

SciTech Connect

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.

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

1996-11-01

183

Commercial aerospace and terrestrial applications of nickel-hydrogen batteries  

Microsoft Academic Search

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

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

1996-01-01

184

Guntersville Workshop on Solar-Terrestrial Studies  

NASA Technical Reports Server (NTRS)

The separation of purely solar physics from magnetospheric physics, and the effects of solar activity on geomagnetic activity are investigations which can be accomplished using the shuttle orbiter in an extended sortie mode, or an unmanned solar terrestrial observatory powered by the power module in an extended duration mode. When the power module is used with the shuttle in a sortie support mode, both the instrument capacity and the time in orbit of the orbiter can be increased several fold. In the free-flyer mode, the power module would be capable of providing power, basic attitude control, basic thermal control and housekeeping communications for unmanned, large, independent mission payloads in low earth orbit for periods of 6 months or longer. Instrument requirements for interdisciplinary joint observational programs are discussed for studies of the magnetosphere, the atmosphere, sun-weather relationships. Description summary charts of the power module are included.

1977-01-01

185

Contaminant Exposure in Terrestrial Vertebrates  

EPA Science Inventory

Manuscript is a critical review of the state of the science for quantifying exposures of terrestrial wildlife species to chemical contamination. It describes the unique aspects of birds, mammals, reptiles, amphibians and threatened and endangered species. Fate and transport of ...

186

Evolution of the Terrestrial Atmospheres  

NSDL National Science Digital Library

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

O'Connell, Robert

2005-06-28

187

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)

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.

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

2011-09-01

188

The terrestrial impact cratering record.  

NASA Astrophysics Data System (ADS)

Approximately 130 terrestrial hypervelocity impact craters are currently known. The rate of discovery of new craters is 3 - 5 craters per year. Although modified by erosion, terrestrial impact craters exhibit the range of morphologies observed for craters on other terrestrial planetary bodies. Due to erosion and its effects on form, terrestrial craters are recognized primarily by the occurrence of shock metamorphic effects. Terrestrial craters have a set of geophysical characteristics which are largely the result of the passage of a shock wave and impact-induced fracturing. Much current work is focused on the effects of impact on Earth evolution. Previous work on shock metamorphism and the contamination of impact melt rocks by meteoritic siderophile elements provides a basis for the interpretation of the physical and chemical evidence from Cretaceous-Tertiary boundary sites as resulting from a major impact. By analogy with the lunar record and modelling of the effects of very large impacts, it has been proposed that biological and atmospheric evolution of the Earth could not stabilize before the end of the late heavy bombardment ?3.8 Ga ago. The present terrestrial cratering rate is 5.4±2.7×10-15 km-2a-1 for a diameter ?20 km. On a gobal scale, a major impact sufficient to cripple human civilization severely will occur on time scales of ?106a.

Grieve, R. A. F.; Pesonen, L. J.

1992-12-01

189

Applying a Secure and Efficient Low Earth Orbit Satellite-Based Multicast Architecture in a Deployed Environment  

Microsoft Academic Search

Secure, seamless, ubiquitous communications is a necessity to support the demands of today's first responders, whether they are military, disaster response, or Homeland Defense. Low earth orbit communications satellites are an ideal platform to ensure users in the field, at home and around the globe can always access secure networks. Security and efficiency are generally at odds during communications system

Victor P. Hubenko; Richard A. Raines; Rusty O. Baldwin; Barry E. Mullins; Robert F. Mills; Michael R. Grimaila

2007-01-01

190

Moderation of ensemble covariances for data assimilation of satellite-based water level observations into flood modelling  

NASA Astrophysics Data System (ADS)

Satellite imagery has proved useful for obtaining information on water levels in flood events. Microwave frequencies are generally more useful for flood detection than visible-band sensors because of their all-weather day-night capability. Specifically, the future SWOT mission, with Ka-band interferometry, will be able to provide direct Water Level Observations (WLOs), and current and future Synthetic Aperture Radar (SAR) sensors can provide information of flood extent, which, when intersected with a Digital Elevation Model (DEM) of the floodplain, provides indirect WLOs. By either means, satellite-based WLOs can be assimilated into a hydrodynamic model to decrease forecast uncertainty and further to estimate river discharge into the flooded domain and model parameters. However, studies on assimilation of real satellite-based WLOs into flood models are still sparse. For 2D high resolution flood modelling, the data assimilation (DA) techniques based on Monte Carlo implementations of the Kalman filter (Ensemble Kalman Filters; EKFs) provide a minimum variance estimator. The performance of ensemble techniques depends on the quality of both the observations to be assimilated and the correctness of the several covariance matrices involved, which serve to convey the observation information (innovations) to elsewhere in the studied domain. Here we evaluate how some of the particularities of flood models may hamper the straightforward implementation of EKFs for operational assimilation of satellite-based WLOs. Specifically, the filter may become hyper-sensitive to observations in minor tributaries, and the specific network connectivity of braided flooded domains (e.g. converging tributaries or urban domains) indicate that straightforward spatial localization (Euclidean distance-based covariance moderation) is just not sound. Here we discuss these problems by assimilating real WLOs obtained from a 7-image sequence from the COSMO-Skymed (CSK) constellation X-band SAR, in a flood that occurred in November 2012 in the lower Severn-Avon rivers, Southwest UK (perhaps the most detailed sequence of SAR-based WLOs of a flood event currently existing in the world). We evaluate the effect of moderating the covariance matrices, to counteract the abovementioned problems, on the assimilation-constrained dynamic footprints of the flood forecast.

García-Pintado, Javier; Mason, David Cecil; Dance, Sarah Louise

2014-05-01

191

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

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

192

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

USGS Publications Warehouse

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.

Jones, J. W.; Jarnagin, T.

2009-01-01

193

Integrating TWES and Satellite-based remote sensing: Lessons learned from the Honshu 2011 Tsunami  

NASA Astrophysics Data System (ADS)

The Boxing Day Tsunami killed 240,000 people and inundated the affected shorelines with waves reaching heights up to 30m. Tsunami Early Warning Capabilities have improved in the meantime by continuing development of modular Tsunami Early Warning Systems (TEWS). However, recent tsunami events, like the Chile 2010 and the Honshu 2011 tsunami demonstrate that the key challenge for TEWS research still lies in the timely issuing of reliable early warning messages to areas at risk, but also to other stakeholders professionally involved in the unfolding event. Until now remote sensing products for Tsunami events, including crisis maps and change detection products, are exclusively linked to those phases of the disaster life cycle, which follow after the early warning stage: Response, recovery and mitigation. The International Charter for Space and Major Disasters has been initiated by the European Space Agency (ESA) and the Centre National d'Etudes Spatiales (CNES) in 1999. It coordinates a voluntary group of governmental space agencies and industry partners, to provide rapid crisis imaging and mapping to disaster and relief organisations to mitigate the effects of disasters on human life, property and the environment. The efficiency of this approach has been demonstrated in the field of Tsunami early warning by Charter activations following the Boxing Day Tsunami 2004, the Chile Tsunami 2010 and the Honshu Tsunami 2011. Traditional single-satellite operations allow at best bimonthly repeat rates over a given Area of Interest (AOI). This allows a lot of time for image acquisition campaign planning between imaging windows for the same AOI. The advent of constellations of identical remote sensing satellites in the early 21st century resulted both in daily AOI revisit capabilities and drastically reduced time frames for acquisition planning. However, the image acquisition planning for optical remote sensing satellite constellations is constrained by orbital and communication requirements: Defined time slots exist to commandeer the tasking of image acquisitions. If such a time slot has been missed, another attempt to image an AOI again can only be attempted ca. 24 hours later, due to the sun-synchronous satellite orbits Therefore it is critical to establish automated Disaster Early Warning dissemination services for the remote sensing community, to supply them with the timeliest opportunity to trigger the tasking process for the affected AOI. For very large events like a Tsunami in the Pacific, this approach provides the chance to gain additional pre-disaster imagery as a reference for change detection. In the case of the Tohoku earthquake, an ad-hoc warning dissemination process was manually dispatched by the Centre for Geoinformation Technology (CeGIT) at the German Research Centre for Geoscience, contacting RapidEye AG, once the severity of the earthquake event had been confirmed by the GEOFON geoseismic network. RapidEye AG decided to launch an imaging campaign which yielded 78 georectified image tiles (L3A) of Honshu island during the next imaging window. Of these, 26 tiles cover the affected coastline, resulting in 16,250km² of content for crisis mapping effort such as the Humanitarian Open Street Map (OSM) Team. This data was made available by RapidEye as a part of the Charter Activiation requested by Japan on March 11 2011. [1] Hoja, D., Schwinger, M.,Wendleder A.,Löwe, P., Konstanski, H., Weichelt, H.: Optimised Near-Real Time Data Acquisition for Disaster Related Rapid Mapping

Löwe, Peter; Wächter, Joachim

2013-04-01

194

Satellite-aided land mobile communications system implementation considerations  

NASA Technical Reports Server (NTRS)

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.

Leroy, B. E.

1982-01-01

195

Groundwater and Terrestrial Water Storage  

NASA Technical Reports Server (NTRS)

Groundwater is a vital resource and also a dynamic component of the water cycle. Unconfined aquifer storage is less responsive to short term weather conditions than the near surface terrestrial water storage (TWS) components (soil moisture, surface water, and snow). However, save for the permanently frozen regions, it typically exhibits a larger range of variability over multi-annual periods than the other components. Groundwater is poorly monitored at the global scale, but terrestrial water storage (TWS) change data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission are a reasonable proxy for unconfined groundwater at climatic scales.

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

2012-01-01

196

Communicating About Communicable Disease  

NSDL National Science Digital Library

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.

IBM's Teachers Try Science program

2011-11-23

197

Proactive TCP Mechanism to Improve Handover Performance in Mobile Satellite and Terrestrial Networks  

NASA Astrophysics Data System (ADS)

Emerging standardization of Geo Mobile Radio (GMR-1) for satellite system is having strong resemblance to terrestrial GSM (Global System for Mobile communications) at the upper protocol layers and TCP (Transmission Control Protocol) is one of them. This space segment technology as well as terrestrial technology, is characterized by periodic variations in communication properties and coverage causing the termination of ongoing call as connections of Mobile Nodes (MN) alter stochastically. Although provisions are made to provide efficient communication infrastructure this hybrid space and terrestrial networks must ensure the end-to-end network performance so that MN can move seamlessly among these networks. However from connectivity point of view current TCP performance has not been engineered for mobility events in multi-radio MN. Traditionally, TCP has applied a set of congestion control algorithms (slow-start, congestion avoidance, fast retransmit, fast recovery) to probe the currently available bandwidth on the connection path. These algorithms need several round-trip times to find the correct transmission rate (i.e. congestion window), and adapt to sudden changes connectivity due to handover. While there are protocols to maintain the connection continuity on mobility events, such as Mobile IP (MIP) and Host Identity Protocol (HIP), TCP performance engineering has had less attention. TCP is implemented as a separate component in an operating system, and is therefore often unaware of the mobility events or the nature of multi-radios' communication. This paper aims to improve TCP communication performance in Mobile satellite and terrestrial networks.

Vinayakray-Jani, Preetida; Sanyal, Sugata

2012-06-01

198

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

NASA Astrophysics Data System (ADS)

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).

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

2012-12-01

199

Furostanol saponins from Tribulus terrestris.  

PubMed

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. PMID:12946722

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

2003-09-01

200

Atmospheric Circulation of Terrestrial Exoplanets  

NASA Astrophysics Data System (ADS)

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 Hadley circulation, wave adjustment of the thermal structure, and the tendency toward equatorial superrotation in the slowly rotating regime (the "tropics"). We then survey key elements of the hydrological cycle, including the factors that control precipitation, humidity, and cloudiness. Next, we summarize key mechanisms by which the circulation affects the global-mean climate, and hence planetary habitability. In particular, we discuss the runaway greenhouse, transitions to snowball states, atmospheric collapse, and the links between atmospheric circulation and CO2 weathering rates. We finish by summarizing the key questions and challenges for this emerging field in the future.

Showman, A. P.; Wordsworth, R. D.; Merlis, T. M.; Kaspi, Y.

201

Furostanol saponins from Tribulus terrestris  

Microsoft Academic Search

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.

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

2003-01-01

202

ExtraTerrestrial Radio Transmissions  

Microsoft Academic Search

WE are witness again to a surge of interest in, and speculation about, extra-terrestrial radio transmissions which had an earlier flare in the late twenties1. The favourable change in climate for the expression of such ideas since the turn of the century has been of particular interest to me. In 1899, Nikola Tesla established an experimental station at Colorado Springs,

Leland I. Anderson

1961-01-01

203

Application of Satellite Based Imagery and Altimetry to Estimation of River Hydraulics and Remote Estimation of River Discharge  

NASA Astrophysics Data System (ADS)

The response, or residual, of hydrologic climate variables on the land surface is river discharge. The flow in a river reflects the difference between precipitation on the land surface and evapotranspiration from the land surface, and incorporates the surface and groundwater runoff components of the combined effect of land cover, soil characteristics, soil moisture, and subsurface flow from aquifers. As such, river discharge is a fundamental hydrologic variable that needs to be quantified in order to assess any element of the land surface hydrology. Typically, river discharge is measured on the ground at specific locations in a river. A stream gage requires not only tracking of hydraulic variables at many locations but many direct measurements of discharge at each location through any given year to track change and derive relationships between the measured hydraulic variables. These direct measurements require manpower and are limited by cost and accessibility. Remote sensing offers wide spatial coverage and the possibility measuring hydraulic variables that can enable discharge to be deduced. This would serve as a useful tool supplementing on-the-ground stream gaging networks and providing data for regions where data or location are inaccessible. We explore here the application of remotely sensed river width and river water-surface height (stage and slope) to estimate the discharge, depth, and velocity of rivers. The imagery is based on Landsat ETM+ and TM Imagery acquired between 2002 and 2009. With a combination of manual digitization and automatic classification methods, the river section area at four designated river reaches on the Mississippi/Missouri river basin were determined. Accuracy assessments were made in terms of method and the effects of clouds, snow, and ice. A time series of water-surface areas for each location were thus developed, and found to show seasonal variability correlated with seasonal discharge. However, a reasonable correlation between river surface area and discharge was not found at all of the sites, indicating that width-discharge relations will not always provide consistent and reasonable estimates of the river discharge. The ICESat/GLAS laser altimeter and the NASA/CNES OSTM and ESA ENVISAT radar altimeters also cross these river reaches at specific locations. Deduced altimetric surface elevation variations based on GLA14/GLA06 and GDR data sets for the 2002-2010 period show variable accuracy when compared to gauge data, but are used to derive surface slope estimates. The combined satellite-based parameters provide reasonable estimates of river discharge, depth, and velocity. Issues concerning the satellite-based observation frequency, and the accuracy of the altimetric and imaging estimates are evaluated and discussed with regard to the resolution and monitoring of river hydraulic conditions.

Bjerklie, D. M.; Birkett, C. M.; Li, Y.; Dubayah, R.; Hofton, M. A.

2010-12-01

204

Understanding tree growth in response to moisture variability: Linking 32 years of satellite based soil moisture observations with tree rings  

NASA Astrophysics Data System (ADS)

Climate change induced drought variability impacts global forest ecosystems and forest carbon cycle dynamics. Physiological drought stress might even become an issue in regions generally not considered water-limited. The water balance at the soil surface is essential for forest growth. Soil moisture is a key driver linking precipitation and tree development. Tree ring based analyses are a potential approach to study the driving role of hydrological parameters for tree growth. However, at present two major research gaps are apparent: i) soil moisture records are hardly considered and ii) only a few studies are linking tree ring chronologies and satellite observations. Here we used tree ring chronologies obtained from the International Tree ring Data Bank (ITRDB) and remotely sensed soil moisture observations (ECV_SM) to analyze the moisture-tree growth relationship. The ECV_SM dataset, which is being distributed through ESA's Climate Change Initiative for soil moisture covers the period 1979 to 2010 at a spatial resolution of 0.25°. First analyses were performed for Mongolia, a country characterized by a continental arid climate. We extracted 13 tree ring chronologies suitable for our analysis from the ITRDB. Using monthly satellite based soil moisture observations we confirmed previous studies on the seasonality of soil moisture in Mongolia. Further, we investigated the relationship between tree growth (as reflected by tree ring width index) and remotely sensed soil moisture records by applying correlation analysis. In terms of correlation coefficient a strong response of tree growth to soil moisture conditions of current April to August was observed, confirming a strong linkage between tree growth and soil water storage. The highest correlation was found for current April (R=0.44), indicating that sufficient water supply is vital for trees at the beginning of the growing season. To verify these results, we related the chronologies to reanalysis precipitation and temperature datasets. Precipitation was important during both the current and previous growth season. Temperature showed the strongest correlation for previous (R=0.12) and current October (R=0.21). Hence, our results demonstrated that water supply is most likely limiting tree growth during the growing season, while temperature is determining its length. We are confident that long-term satellite based soil moisture observations can bridge spatial and temporal limitations that are inherent to in situ measurements, which are traditionally used for tree ring research. Our preliminary results are a foundation for further studies linking remotely sensed datasets and tree ring chronologies, an approach that has not been widely investigated among the scientific community.

Albrecht, Franziska; Dorigo, Wouter; Gruber, Alexander; Wagner, Wolfgang; Kainz, Wolfgang

2014-05-01

205

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

NASA Astrophysics Data System (ADS)

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. The use of a new set of aerosol models assuming wavelength-dependent aerosol absorption in the near-UV region (Absorption Angstrom Exponent ?-2.5 to -3.0) improved the OMAERUV retrieval results by significantly reducing the AOD bias observed when gray aerosols were assumed. In addition, the new retrieval of single-scattering albedo is in better agreement with those of AERONET within the uncertainties (?SSA = ±0.03). The new colored carbonaceous aerosol model was also found to reproduce the ground-based AOD observations over the biomass burning region of central Africa and northern India. Together with demonstrating a significant improvement in the retrieval of aerosol properties from OMI, the present study highlights the greater sensitivity of the near-UV measurements to the varying spectral aerosol absorption. This capability can be explored further for the use in the identification of the black carbon and organics in the biomass burning aerosols.

Jethva, H.; Torres, O.

2011-10-01

206

Study terrestrial applications of solar cell powered systems  

NASA Technical Reports Server (NTRS)

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.

Ravin, J. W.

1973-01-01

207

Formation of the terrestrial planets from planetesimals  

NASA Technical Reports Server (NTRS)

Formation of the terrestrial planets from planetesimals is discussed. The following subject areas are covered: (1) formation of the original planetesimals; (2) growth of planetesimals into planetary embryos; and (3) growth of runaway planetary embryos into terrestrial planets.

Wetherill, George W.

1991-01-01

208

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...

209

Transfer of radionuclides in the terrestrial environment.  

National Technical Information Service (NTIS)

The transfer of radionuclides in the terrestrial environment have been investigated. The thesis is divided into two parts. Part I; Dynamic model for the transfer of radionuclides in the terrestrial environment. The study comprises the development of a com...

M. Oehlenschlaeger

1991-01-01

210

A Comparison of Two Above-Ground Biomass Estimation Techniques Integrating Satellite-Based Remotely Sensed Data and Ground Data for Tropical and Semiarid Forests in Puerto Rico  

EPA Science Inventory

Two above-ground forest biomass estimation techniques were evaluated for the United States Territory of Puerto Rico using predictor variables acquired from satellite based remotely sensed data and ground data from the U.S. Department of Agriculture Forest Inventory Analysis (FIA)...

211

Integration of satellite-based energy balance with simulation models applied to irrigation management at an irrigation scheme of southern Spain  

NASA Astrophysics Data System (ADS)

This paper combines a water balance model with satellite-based remote-sensing estimates of evapotranspiration (ET) to provide accurate irrigation scheduling guidelines for individual fields. The satellite-derived ET was used in the daily soil water balance model to improve accuracy of field-by-field ET demands and subsequent field-scale irrigation schedules. The combination of satellite-based ET with daily soil water balance incorporates the advantages of satellite remote-sensing and daily calculation time steps, namely, high spatial resolution and high temporal resolution. The procedure was applied to Genil - Cabra Irrigation Scheme in Spain, where irrigation water supply is often limited by regional drought. Compared with traditional applications of water balance models (i.e. without the satellite-based ET), the combined procedure provided significant improvements in irrigation schedules for both the average condition and when considering field-to-field variability. A 24% reduction in water use was estimated for cotton if the improved irrigation schedules were followed. Irrigation efficiency calculated using satellite-based ET and actual applied irrigation water helped to identify specific agricultural fields experiencing problems in water management, as well as to estimate general irrigation efficiencies of the scheme by irrigation and crop type. Estimation of field irrigation efficiency ranged from 0.72 for cotton to 0.90 for sugar beet.

Santos, Cristina; Lorite, Ignacio J.; Tasumi, Masahiro; Allen, Richard G.; Gavilán, Pedro; Fereres, Elías

2007-10-01

212

Long-term solar-terrestrial observations  

NASA Technical Reports Server (NTRS)

The results of an 18-month study of the requirements for long-term monitoring and archiving of solar-terrestrial data is presented. The value of long-term solar-terrestrial observations is discussed together with parameters, associated measurements, and observational problem areas in each of the solar-terrestrial links (the sun, the interplanetary medium, the magnetosphere, and the thermosphere-ionosphere). Some recommendations are offered for coordinated planning for long-term solar-terrestrial observations.

1988-01-01

213

A comparison of two ground-based lightning detection networks against the satellite-based lightning imaging sensor (LIS)  

NASA Astrophysics Data System (ADS)

We compared lightning stroke data from the ground-based World Wide Lightning Location Network (WWLLN) and lightning stroke data from the ground-based Earth Networks Total Lightning Network (ENTLN) to lightning group data from the satellite-based Lightning Imaging Sensor (LIS) from 1 January 2010 through 30 June 2011. The region of study, about 39°S to 39°N latitude, 164°E to 17°W longitude, chosen to approximate the Geostationary Lightning Mapper (GLM) field of view, was considered in its entirety and then divided into four geographical sub-regions. We found the highest 18-mon WWLLN coincidence percent (CP) value in the Pacific Ocean at 18.9% and the highest 18-mon ENTLN CP value in North America at 63.3%. We found the lowest 18-mon CP value for both WWLLN and ENTLN in South America at 6.2% and 2.2% respectively. Daily CP values and how often large radiance LIS groups had a coincident stroke varied. Coincidences between LIS groups and ENTLN strokes often resulted in more cloud than ground coincidences in North America and more ground than cloud coincidences in the other three sub-regions.

Thompson, Kelsey B.

214

Comparison of in-situ, aircraft, and satellite based land surface temperature measurements over a mixed agricultural region  

NASA Astrophysics Data System (ADS)

Land surface temperature (LST) is a key variable in the study of the exchange of energy and water between the land surface and the atmosphere, and it influences land surface physical processes at regional and global scales. With the objective of quantifying the spatial variability and overall representativeness of single-point surface temperature measurements and to improve the accuracy of satellite LST measurements, airborne campaigns were conducted over a mixed agricultural area near Bondville, Illinois during 2012 and 2013. During the campaigns, multiple measurements of surface temperature were made using infra-red temperature sensors at micrometeorological tower sites, which include NOAA's Climate Reference Network (CRN) and nearby flux tower sites, and onboard an instrumented Piper Navajo airborne research aircraft. In addition to this, daily LST products from the Moderate Resolution Imaging Spectroradiometer (MODIS), onboard the NASA Terra and Aqua Earth Observing System satellites were used. The aircraft-based and satellite-based LST measurements were compared with the in situ, tower-based LST measurements. Observations indicate large spatial and temporal variability of land surface temperature over the Bondville area. Our results show good agreement between in situ, aircraft and satellite measurements. The agreement was better with the LST data from the flux tower than those from CRN tower.

Krishnan, P.; Baker, B.; Kochendorfer, J.; Dumas, E.; Meyers, T. P.; Guillevic, P. C.; Corda, S.; Muratore, J. F.; Simmons, D.

2013-12-01

215

Limitations of microphysical property retrievals in marine water clouds based on satellite-based passive remote sensing  

NASA Astrophysics Data System (ADS)

In satellite-based passive remote sensing, the cloud droplet effective radius (re), which has a strong influence on cloud radiative effects, is derived together with cloud optical thickness (?) from reflectance measurements at two wavelengths, so called bi-spectral method. Since the bias to the re of marine water clouds can lead to a global radiative forcing error, it is critical to identify the sources and magnitudes of errors in the retrieval. Due to the use of loop-up tables, a bi-spectral method has limitations in optical and microphysical properties retrieval. It might be problematic for optically very thin clouds, and also erroneous for the clouds having very large radius droplets or large thickness due to the upper limits of retrieval method. This study investigates the occurrence rate and sources of the failed effective radius retrievals on Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Aqua satellite together with Cloud Profiling Radar (CPR) observation on CloudSat satellite. First, a typical failed retrieval case will be shown to identify the characteristics. And, we investigate potential reasons of failed retrieval by demonstrating the dependency on the relevant parameters, such as optical thickness, horizontal homogeneity and reflectances. The difference between collections of MODIS data set will also be investigated. The CPR measurement collocated with MODIS can help to identify the source of failed retrieval, especially for the large particle. Preliminary result shows that the significant fractions (about 15%) of water clouds are failed in the MODIS re retrievals.

Cho, H.; Zhang, Z.; Platnick, S.; Lebsock, M. D.

2012-12-01

216

Assimilation of Satellite-based AMSR-E Streamflow for Improving Flood Modeling in Okavango River Basin, Africa  

NASA Astrophysics Data System (ADS)

Flooding is one of the most frequently occurring and disastrous natural hazards in the world. In this study, the focus is on the application of hydrologic modeling for flood prediction in ungauged basins. TRMM-RT (Tropical Rainfall Measuring Mission, Real Time) rainfall data were used as the forcing data for a conceptual hydrological model called HyMOD. After the model parameters were automatically estimated using DREAM (Differential Evolution Adaptive Metropolis), an ensemble square root filter was used to assimilate the AMSR-E (Advanced Microwave Scanning Radiometer - Earth Observing System) signal. Statistical indices indicate improved modeling of streamflow, which was particularly the case during high flow events, following the assimilation of the AMSR-E data, thus providing a capability to provide early warning of flooding in the Okavango river basin. Given the global availability of satellite-based precipitation and streamflow information in near real-time, the data assimilation approach can exploit and utilize the potentiality of remote-sensing data in flood detection and prediction for vast poorly ungauged basins around the world.

Zhang, Y.; Hong, Y.; Gourley, J. J.; Wang, X.; Gao, J.; Vergara, H. J.

2011-12-01

217

High-power optical amplifiers enable 1550-nm terrestrial free-space optical data links operating at WDM 2.5Gb\\/s data rates  

Microsoft Academic Search

Optical amplifiers are an enabling technology for free space laser communications. Transmission of four multiplexed 2.5 Gbps channels at 1550 nm over a 4.4 km terrestrial link is described and modeled.

Paul F. Szajowski; Gerald Nykolak; James J. Auborn; Herman M. Presby; G. E. Tourgee; Dennis M. Romain

1999-01-01

218

Satellite-Based Videoconferencing.  

ERIC Educational Resources Information Center

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,…

Distance Education Report, 1997

1997-01-01

219

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

Microsoft Academic Search

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

M. Schmidt

1999-01-01

220

Propagation prediction models for wireless communication systems  

Microsoft Academic Search

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

Magdy F. Iskander; Zhengqing Yun

2002-01-01

221

Spread spectrum access methods for wireless communications  

Microsoft Academic Search

The authors present an overview of the characteristics of code division multiple access (CDMA) as it is currently being envisioned for use in wireless communications. There are many considerations in the design of such systems, and there are multiple designs being discussed. CDMA has been proposed for both terrestrial links and satellite links. However, there are key differences in the

Ryuji Kohno; Reuven Meidan; Laurence B. Milstein

1995-01-01

222

NASA standard communications and data handling subsystem  

Microsoft Academic Search

The paper gives a functional description and discusses hardware implementation for the Communication and Data Handling (C&DH) subsystem of the Multimission Modular Spacecraft. The C&DH subsystem: (1) provides the command and telemetry link between the spacecraft and the terrestrial system, (2) distributes commands to and collects telemetry from all spacecraft systems via a duplex serial multiplex data bus and remote

D. L. Robinson

1977-01-01

223

Project Universe - Local area networks and satellite communications  

Microsoft Academic Search

A high-speed digital communications system is discussed in which a satellite is used to link a number of local area networks which interconnect a variety of computer facilities. The advantages of satellite communications compared with terrestrial links are described, together with a historical survey of the use of the Orbital Test Satellite (OTS) for data experiments. A description of Project

B. R. Ackroyd

1983-01-01

224

Terrestrial photovoltaic collector technology trends  

NASA Technical Reports Server (NTRS)

Following the path of space PV collector development in its early stages, terrestrial PV technologies based upon single-crystal silicon have matured rapidly. Currently, terrestrial PV cells with efficiencies approaching space cell efficiencies are being fabricated into modules at a fraction of the space PV module cost. New materials, including CuInSe2 and amorphous silicon, are being developed for lowering the cost, and multijunction materials for achieving higher efficiency. Large grid-interactive, tracking flat-plate power systems and concentrator PV systems totaling about 10 MW, are already in operation. Collector technology development both flat-plate and concentrator, will continue under an extensive government and private industry partnership.

Shimada, K.; Costogue, E.

1984-01-01

225

NEON Airborne Remote Sensing of Terrestrial Ecosystems  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

226

Terrestrial based inflatable dish antennas  

Microsoft Academic Search

A terrestrial based 4.8-meter dish is presented. The dish is constructed using lightweight, thin film technologies used in spaced-based platforms. Seaming two parabolic dish films together forms a lenticular. One film is coated with a silver flake conductive paint, and the other is RF transparent. The lenticular is inflated to hold the parabolic shape of the dish. The lenticular is

Lany T. Lowe; Ronald D. Hackett

2003-01-01

227

Two sapogenins from tribulus terrestris  

Microsoft Academic Search

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.

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

1998-01-01

228

Communications Pretesting.  

National Technical Information Service (NTIS)

The majority of social development programs around the world stand to benefit from communicating their activities through the mass media. Most program administrators will invest in communication that will effectively reach a target population but will avo...

1978-01-01

229

Lightwave Communications.  

ERIC Educational Resources Information Center

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)

Rheam, Harry

1993-01-01

230

Communicating Science  

USGS Publications Warehouse

For science to have an impact, it must be communicated and easily accessible. The USGS National Wetlands Research Center communicates its research findings through several ways: publishing, the Web, the library, and education and outreach.

Farris, Gaye S.

2005-01-01

231

Hourly soil moisture mapping over West Africa using AMSR-E observations and a satellite-based rainfall product  

NASA Astrophysics Data System (ADS)

This paper provides an original and simple methodology to map surface soil moisture with a fine temporal and spatial resolution over large areas based on a satellite rainfall accumulation product and soil microwave emission measurements at C-band. The first motivation of this study was to obtain high temporal frequency (~1 h) in order to study the possible feedback mechanisms between soil moisture and convection in West Africa. The use of soil moisture maps derived from satellite microwave measurements was not possible due to the low (at best daily) temporal resolution. Thus, a rainfall accumulation product based on Meteosat geostationary satellite measurements was used together with a simple Antecedent Precipitation Index (API) model to produce soil moisture map at the 10×10 km2 and 30 min resolution. Due to uncertainties on the satellite-based rainfall accumulation product, derived soil moisture maps were found to be erroneous. An assimilation technique based on AMSR-E C-band measurements into a microwave emission model was developed. The assimilation technique described in this study consists of modulating the rainfall accumulation estimate between two successive AMSR-E brightness temperatures (TB) measurements in order to match simulated and observed TB. When a rainfall event happens, the initial rainfall accumulation estimate is modulated using a multiplicative factor ranging from 0 to 7. The best solution is given by the rainfall rate which minimizes the difference between observed and simulated TB. Ground-based soil moisture measurements obtained at three sites in Niger, Mali and Benin were used to assess the methodology which was found to improve the soil moisture estimates over the three sites.

Pellarin, T.; Tran, T.; Cohard, J.-M.; Galle, S.; Laurent, J.-P.; de Rosnay, P.; Vischel, T.

2009-06-01

232

Satellite-based estimates of light-use efficiency in a subtropical mangrove forest equipped with CO2 eddy covariance  

NASA Astrophysics Data System (ADS)

Despite the importance of mangrove ecosystems in the global carbon budget, the relationships between environmental drivers and carbon dynamics in these forests remain poorly understood. This limited understanding is partly a result of the challenges associated with in situ flux studies. Tower-based carbon dioxide eddy covariance (EC) systems are installed in only a few mangrove forests worldwide and the longest EC record from the Florida Everglades contains less than 9 yr of observations. A primary goal of the present study was to develop a methodology to estimate canopy-scale photosynthetic light use efficiency in this forest. These tower-based observations represent a basis for associating CO2 fluxes with canopy light use properties, and thus provide the means for utilizing satellite-based reflectance data for larger-scale investigations. We present a model for mangrove canopy light use efficiency utilizing the enhanced green vegetation index (EVI) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) that is capable of predicting changes in mangrove forest CO2 fluxes caused by a hurricane disturbance and changes in regional environmental conditions, including temperature and salinity. Model parameters are solved for in a Bayesian framework. The model structure requires estimates of ecosystem respiration (RE) and we present the first-ever tower-based estimates of mangrove forest RE derived from night-time CO2 fluxes. Our investigation is also the first to show the effects of salinity on mangrove forest CO2 uptake, which declines 5% per each 10 parts per thousand (ppt) increases in salinity. Light use efficiency in this forest declines with increasing daily photosynthetic active radiation, which is an important departure from the assumption of constant light use efficiency typically applied in satellite-driven models. The model developed here provides a framework for estimating CO2 uptake by these forests from reflectance data and information about environmental conditions.

Barr, J. G.; Engel, V.; Fuentes, J. D.; Fuller, D. O.; Kwon, H.

2012-11-01

233

Combining ground-based with satellite-based measurements in the atmospheric state retrieval: Assessment of the information content  

NASA Astrophysics Data System (ADS)

Remote sensing techniques offer the unique possibility to continuously and automatically monitor the atmospheric state from ground and space. Ground-based microwave radiometers (MWRs), for example, are frequently used for temperature and humidity profiling of the lower troposphere. In order to improve the profiles in the middle and upper troposphere, further information is needed. In this respect, satellite measurements are expected to be very useful. In this study, the synergy benefit in temperature and humidity clear-sky profiling using different combinations of state-of-the-art microwave and infrared ground- and satellite-based instruments is assessed. The synergy benefit is regarded as the information gain in light of ground-based MWR observations together with some climatological a priori knowledge. The maximum information content for this kind of synergy is estimated by assuming optimum conditions, e.g., no forward model uncertainties and a horizontal homogeneous atmosphere. For a midlatitude site, the ground-based MWR gives about 4.4 and 2.4 independent pieces of information on the temperature and humidity profile, respectively. For the temperature profile, the combination with Improved Atmospheric Sounding in the Infrared (IASI) and Atmospheric Microwave Sounding Unit-A/Microwave Humidity Sounder (AMSU-A/MHS) increases the information by a factor of about 1.8 and 1.5, respectively, with highest benefit in warm and/or humid conditions. The vertical information on humidity is significantly improved by highly spectrally resolved IR observations from ground or space when the atmosphere is cold and dry; the vertical information is more than tripled. If measurements from AMSU-A/MHS, IASI, or Spinning Enhanced Visible and Infrared Imager are included, retrieval uncertainties in the middle and upper troposphere are significantly reduced by up to 68%.

Ebell, K.; Orlandi, E.; Hünerbein, A.; LöHnert, U.; Crewell, S.

2013-07-01

234

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

NASA Astrophysics Data System (ADS)

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 "gray" aerosol, meaning no wavelength dependence in aerosol absorption. With this assumption, OMI-derived aerosol optical depth (AOD) is found to be over-estimated significantly compared to that of AERONET at several sites during intense biomass burning events (August-September). The assumption on height of aerosols and other parameters seem to be reasonable and unable to explain large discrepancy in the retrieval. The specific ground-based studies have revealed strong spectral dependence in aerosol absorption in the near-UV region that indicates the presence of organic carbon. A new set of OMI aerosol retrieval with assumed wavelength-dependent aerosol absorption in the near-UV region (Absorption Angstrom Exponent ?-2.5 to -3.0) provided much improved retrieval of AOD with significantly reduced bias. Also, the new retrieval of single-scattering albedo is in better agreement with those of AERONET within the uncertainties (??=±0.03). The new smoke aerosol model was also found to be valid over the biomass burning region of central Africa and northern India. Together with suggesting vast improvement in the retrieval of aerosol properties from OMI, present study demonstrates the near-UV capabilities of OMI in separating aerosols containing organics from pure black carbon through OMI-AERONET integrated measurements.

Jethva, H.; Torres, O.

2011-03-01

235

Assimilation of Tower and Satellite-Based Observations for Improved Estimation of Methane Fluxes over Northern Eurasia  

NASA Astrophysics Data System (ADS)

Changes in greenhouse gas emissions such as methane and carbon dioxide from high-latitude wetlands in a warming climate have important implications for global warming, due to the large amounts of carbon stored in high-latitude soils and the high greenhouse warming potential of methane. As much as 1/3 of global natural methane emissions come from high latitudes. Efforts to monitor high-latitude greenhouse gas emissions are hampered by the sparseness of in situ observations at high latitudes, especially in Northern Eurasia. One promising approach is to assimilate spatially sparse tower- and satellite-based observations into large-scale process-based models. In addition, because methane fluxes are sensitive to hydrologic variables such as inundation, passive microwave satellite observations of surface water can also be assimilated. Here we apply an ensemble Kalman smoother to assimilate in situ and satellite observations into our modeling framework, which consists of the Variable Infiltration Capacity (VIC) model, extended to include carbon cycling and coupled to a methane emissions model. This framework is, in turn, coupled to the atmospheric tracer model of Japan's National Institute for Environmental Studies (NIES) to estimate methane concentrations over the West Siberian Lowlands. Observations assimilated include methane concentrations at towers operated by NIES, total column methane concentrations observed by the JAXA GOSAT satellite, and the surface water product of NASA's Jet Propulsion Laboratory derived from AMSR-E and QuickScat observations. We compare the performance of assimilations using these different types of observations and explore how these observations constrain model parameters such as soil moisture content, water table depth distribution, and soil carbon content.

Bohn, T. J.; Schroeder, R.; Podest, E.; McDonald, K. C.; Maksyutov, S.; Lettenmaier, D. P.

2011-12-01

236

Enhancing a global satellite-based Landslide hazard Algorithm with regional applications in Central America and the Caribbean  

NASA Astrophysics Data System (ADS)

A satellite-based landslide algorithm has been developed using land surface information and multi-satellite rainfall data to address landslide susceptibility dynamically. The evaluation of this global system indicates that principally three factors limit the algorithm's performance, including unsuitable weighting of several surface input parameters to the susceptibility map, under-estimation of rainfall accumulations, and incompleteness of the landslide inventories. To address these limitations and refine the methodology used to calculate the input variables for the algorithm this research considers the algorithm components at a regional scale focusing on Central America and the Caribbean. Drawing upon available landslide inventories and higher resolution surface products including Shuttle Radar Topography Mission (SRTM) DEMs, land cover, and other parameters, this study identifies regional landslide susceptibility by employing several different techniques. Susceptibility maps are compiled for multiple test regions and compared using sensitivity analysis of the input surface parameters, indicating which factors are the primary drivers of successful susceptibility calculations. The rainfall triggering relationship is also considered at the regional scale, considering both in situ and satellite data to better resolve the range of potential rainfall threshold conditions. Additional variables such as soil moisture can be integrated into the susceptibility and rainfall variables to provide a more dynamic estimation of potential landsliding conditions. Regional landslide vulnerability data can then be extracted by incorporating socio-economic data including population density and transportation networks. The improved inputs can then be tested in a regional version of the landslide algorithm and validated for system performance. The results of the regional study indicate that resolution of the input parameters can significantly affect the susceptibility calculations and the rainfall relationship remains a difficult aspect of the algorithm to effectively categorize; however, approaching the algorithm at the regional scale improves algorithm performance and is a crucial component of the second version of this global system.

Kirschbaum, D. B.; Lerner-Lam, A.; Adler, R.; Hong, Y.; Teng, B.

2008-12-01

237

A satellite-based analysis of temporal dynamics in tropospheric nitrogen dioxide levels over large urban agglomerations worldwide  

NASA Astrophysics Data System (ADS)

Satellite observations allow for a consistent perspective on tropospheric nitrogen dioxide at a global scale and their operational status facilitates studies on multi-annual to decadal temporal dynamics. Utilizing close to a decade of data from the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) and the Ozone Monitoring Instrument (OMI) sensors, we present in this contribution a global analysis of the temporal dynamics in tropospheric nitrogen dioxide over the worlds' major urban agglomerations during the last 10 years. The results indicate that while levels of nitrogen dioxide have been slowly declining in most areas of the United States and Europe over the last decade, very rapid increases in tropospheric nitrogen dioxide can be observed over many megacities and other large urban agglomerations throughout most of Asia, often with highly significant trends. Particularly in Eastern China, increases of 10 to 20 percent per year are quite widespread. Some of the large urban agglomerations with the most rapid increase in nitrogen dioxide pollution are Dhaka in Bangladesh, Kabul in Afghanistan, and Tianjin in China, and these are investigated in more detail. An inter-comparison of trends derived separately from SCIAMACHY and OMI shows that in terms of spatial patterns the resulting trends agree quite well between the two instruments, particularly in the more polluted areas. However, at the individual grid cell level substantial differences can be found. In addition, the satellite-based trends in tropospheric nitrogen dioxide levels were compared to those obtained from the European Monitoring and Evaluation Programme (EMEP) chemical transport model over the same time period, and furthermore sampling the model at the same time of day as the satellite overpass, thus eliminating the impact of the distinct diurnal cycle of nitrogen dioxide. While generally a good correspondence in the trends has been found between the two data sources, significant differences occur at the individual grid cell level and in Eastern Europe.

Schneider, Philipp; van der A, Ronald; Valdebenito, Alvaro

2014-05-01

238

Comparative Climatology of Terrestrial Planets  

NASA Astrophysics Data System (ADS)

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

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

239

Communication Speaks  

ERIC Educational Resources Information Center

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…

Kinman, Robin Lynn

2010-01-01

240

Satellite and terrestrial integrated services digital networks in Japan  

NASA Astrophysics Data System (ADS)

Satellite and terrestrial Integrated Services Digital Networks (ISDN) to provide cost effective ISDN services and to enhance installation of ISDN services all over the nation are proposed. The proposed networks are based on the traffic sharing between satellite and terrestrial networks for traffic transmission among telephone offices and provide satellite subscriber lines for ISDN customers in rural areas. The former DYANET (dynamic channel assigning routing satellite aided digital networks) (1) takes the advantage of high transmission efficiency of terrestrial networks for steady traffic and the advantage of high transmission efficiency of satellite communications for light and dynamically varying traffic. By employing demand assignment and transponder hopping (for both transmission and reception) techniques, effective satellite transmission capacity is encreased to five to six times higher than that of preassignment systems. Moreover, earth station cost was significantly reduced by Large Scale Integrated Circuits (LSIC) and Monolithic Integrated Circuit (MIC) implementation and by the development of dual beam antennas. DYANET 1 has been in perfect operation employing 64 Time Division Multiple Access (TDMA) earth stations since 1988 and the latter (DYANET 2) will be put into commercial use from mid 1991.

Yamamoto, Heiichi; Kato, Shuzo

1991-10-01

241

Perioperative communication.  

PubMed

This article has raised the issue of effective communication within the perioperative setting. There are many methods for sending information from one person to another. Most important in effective communication is the clarity of the message and how practitioners check that the recipient understands the intended point. If key aspects in the communication process are not fully understood or utilised, then we subject our patient and our colleagues to potential risk. If poor communication causes untoward and unacceptable consequences then the perioperative practitioner will be accountable for their actions in law and to their regulatory body. The responsibility of effective communication lies with the individual practitioner first and foremost. To prevent poor communication taking place, they should ensure that they have the correct skills to communicate effectively, be that by listening, reflecting on experiences or writing. PMID:19753889

Smith, Brian; Jones, Chris

2009-08-01

242

Placement of UAVs as Communication Relays Aiding Mobile Ad Hoc Wireless Networks  

Microsoft Academic Search

Unmanned aerial vehicles (UAVs) have been used for surveillance and reconnaaissance operations. Such communications enabled platforms can also be effectively utilized to enhance the communications transport capabilitites of a mobile ad hoc wireless network. When properly embedded into the architecture of a communications network, the resultirng UAV aided terrestrial network architecture is expended into a multi-layered hierarchical network structure. The

Izhak Rubin; Runhe Zhang

2007-01-01

243

The 30/20 GHz fixed communications systems service demand assessment. Volume 3: Annex  

NASA Technical Reports Server (NTRS)

A review of studies forecasting the communication market in the United States is given. The applicability of these forecasts to assessment of demand for the 30/20 GHz fixed communications system is analyzed. Costs for the 30/20 satellite trunking systems are presented and compared with the cost of terrestrial communications.

Gamble, R. B.; Seltzer, H. R.; Speter, K. M.; Westheimer, M.

1979-01-01

244

Design and Evaluation of Fiber Direct Coupling Optical Antennas for Next Generation Optical Wireless Communication Systems  

Microsoft Academic Search

It is anticipated that compact optical antennas with an advanced fine optical tracking system will be used for the ultra-fast laser communication system in the next generation. Such laser communication systems will be used not only for the space communications but also the terrestrial long-distance network. In this paper, we discuss demand specifications of optical antennas considering phenomena such as

Koichi Takahashi; Nobuo Nakajima

2010-01-01

245

A Markov chain Monte Carlo algorithm for upscaled soil-vegetation-atmosphere-transfer modeling to evaluate satellite-based soil moisture measurements  

Microsoft Academic Search

A Markov chain Monte Carlo (MCMC) based algorithm was developed to derive upscaled land surface parameters for a soil-vegetation-atmosphere-transfer (SVAT) model using time series data of satellite-measured atmospheric forcings (e.g., precipitation), and land surface states (e.g., soil moisture and vegetation). This study focuses especially on the evaluation of soil moisture measurements of the Aqua satellite based Advanced Microwave Scanning Radiometer

N. N. Das; B. P. Mohanty; E. G. Njoku

2008-01-01

246

Estimating Evapotranspiration Using an Observation Based Terrestrial Water Budget  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

247

Consumer Control of Terrestrial Ecosystems  

NASA Astrophysics Data System (ADS)

More than half of the earth's terrestrial surface is grazed by large herbivores and their effects on plant and soil carbon and nitrogen processes are large and widespread. Yet the large effects of these animals on terrestrial processes have largely been ignored in global change models. This presentation will explore the many pathways that consumers affect short and long time-scale terrestrial nitrogen and carbon processes. Large herbivores influence the quality of soil organic matter and the size of the active (i.e., labile) pool of soil carbon and nitrogen in several ways. Herbivory leads to greater abundance of species producing low quality material in forest and dry grassland, via feeding preferentially on high quality forage, and high quality material in mesic grassland habitat, via the high quality of material that regrows after a plant is grazed. Defoliation stimulates the rate of root exudation that enhances rhizospheric processes and the availability of nitrogen in the plant rhizosphere. Herbivores also change the species composition of mycorrhizae fungal associates that influence plant growth and affect soil structure and the turnover rate of soil carbon. Recent radiocarbon measurements have revealed that herbivores also markedly affect the turnover dynamics of the large pool of old soil carbon. In Yellowstone Park, ungulates slow the mean turnover of the relatively old (i.e., slow and passive) 0 - 20 cm deep soil organic carbon by 350 years in upland, dry grassland and speed up that rate in slope-bottom, mesic grassland by 300 years. This represents a 650 year swing in the turnover period of old soil carbon across the Yellowstone landscape. By comparison, mean turnover time for the old pool of 0 - 10 cm deep soil organic carbon shifts by about 300 years across the steep climatic gradient that includes tropical, temperate, and northern hardwood forest, and tallgrass, shortgrass and desert grassland. This large body of evidence suggests consumers play a major role in global carbon cycling and likely are important regulators of the terrestrial response to climate change.

Frank, D.

2012-12-01

248

W ormhole Caching with HTTP PUSH Method for a Satellite-Based Web Content Multicast and Replication System  

Microsoft Academic Search

A two-tier Web caching and replication system, called the INTELSAT Internet Delivery System (IDS) is discussed. Based on a Wa rehouse-Kiosk paradigm, IDS provides global access and Internet wormholes via a fleet of INTELSAT satellites, the largest commercial satellite communications system in the world. Web content such as cacheable HTTP, FTP and streaming objects are fetched o r pushed both

Hua Chen; Marc Abrams; Tommy Johnson

1999-01-01

249

AIM satellite-based research bridges the unique scientific aspects of the mission to informal education programs globally  

NASA Astrophysics Data System (ADS)

The Education and Public Outreach (EPO) component of the satellite-based research mission "Aeronomy of Ice In the Mesosphere" (AIM) will bridge the unique scientific aspects of the mission to informal education organizations. The informal education materials developed by the EPO will utilize AIM data and educate the public about the environmental implications associated with the data. This will assist with creating a scientifically literate workforce and in developing a citizenry capable of making educated decisions related to environmental policies and laws. The objective of the AIM mission is to understand the mechanisms that cause Polar Mesospheric Clouds (PMCs) to form, how their presence affects the atmosphere, and how change in the atmosphere affects them. PMCs are sometimes known as Noctilucent Clouds (NLCs) because of their visibility during the night from appropriate locations. The phenomenon of PMCs is an observable indicator of global change, a concern to all citizens. Recent sightings of these clouds over populated regions have compelled AIM educators to expand informal education opportunities to communities worldwide. Collaborations with informal organizations include: Museums/Science Centers; NASA Sun-Earth Connection Forum; Alaska Native Ways of Knowing Project; Amateur Noctilucent Cloud Observers Organization; National Parks Education Programs; After School Science Clubs; Public Broadcasting Associations; and National Public Radio. The Native Ways of Knowing Project is an excellent example of informal collaboration with the AIM EPO. This Alaska based project will assist native peoples of the state with photographing NLCs for the EPO website. It will also aid the EPO with developing materials for informal organizations that incorporate traditional native knowledge and science, related to the sky. Another AIM collaboration that will offer citizens lasting informal education opportunities is the one established with the United States National Parks. AIM educators will work directly with the National Parks to develop education packets and web-based materials for their Junior Ranger and Parks as Classrooms programs. AIM education materials will be developed and distributed to park rangers north of 400 in an effort to include NLC observations in their night hikes. This will have a long-term impact reaching out to parents and children in an informal setting for years to come. Each of the AIM informal education collaborations will allow citizens globally an opportunity to share the excitement of the AIM mission.

Robinson, D.; Maggi, B.

2003-04-01

250

Real-time Global Flood Monitoring using an Enhanced Land Surface Model with Satellite-based Precipitation  

NASA Astrophysics Data System (ADS)

A community land surface model (LSM), Variable Infiltration Capacity (VIC) model, was enhanced by coupling with a hierarchical dominant river tracing-based runoff-routing model. The Dominant river tracing-Routing Integrated with VIC Environment (DRIVE) model formed the new core of an existing real-time global flood monitoring system (GFMS). It is the first time to use satellite-based real-time precipitation (with other data) to drive a state-of-the-art LSM for real-time flood monitoring for global domain at relatively high spatial (~12km) and temporal (3-hourly) resolution. In order to evaluate the new GFMS accuracy in flood event detection and flood magnitude estimation, we ran the DRIVE model for retrospective ~15 years (1998~) using both NASA TMPA research and real-time precipitation products, with the model simulations referred to as DRIVE-V7 and DRIVE-RT respectively. The DRIVE-RT and DRIVE-V7 derived very close probability of detection (0.90 vs. 0.93) and false alarm ratio (0.88 vs. 0.84) against archived flood events with duration greater than one day, which are much better than the old GFMS using a simpler hydrologic model driven by TMPA 3B42V6 research product. The DRIVE-V7 derived positive daily and monthly Nash-Sutcliffe coefficient (NSC) for 362 (32.3%) and 675 (60.2%) gauges, out of 1,121 in total from global rivers with observed daily streamflow data, with a mean of 0.39 and 0.212 respectively. It is promising considering the model was using only a priori parameters. The model performance generally decreases from tropics toward higher latitudes at annual, seasonal and daily scales, with DRIVE-V7 generally better than DRIVE-RT. However, their performances at daily scale had no significant difference for almost all regions except the northern mid-latitudes where TMPA V7 research product has much better quality than real-time data because of gauge data based corrections. A real-time evaluation on recent flood cases for the new operational GFMS (http://flood.umd.edu) demonstrated that the new GFMS had a fairly good performance in flood occurrence detection, flood evolution and magnitude calculation according to river gauge data. The GFMS has also been developed to provide flood detection, streamflow and inundation estimation at a much higher resolution (as fine as 1 km). The evaluation also demonstrated that the delineation of floodplain inundation dynamics at the 1km resolution further significantly improved the flood estimation.

Wu, H.; Adler, R. F.; Tian, Y.

2013-12-01

251

The Laboratory for Terrestrial Physics  

NASA Technical Reports Server (NTRS)

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.

2003-01-01

252

Communication tools  

NSDL National Science Digital Library

After completing this project you should be able to answer the question: How can Internet resources be used to improve communication in the classroom? There are different tools that can be used to enhance communication. As you examine each website record your findings in the Supporting communcation recording chart. Which tool did you like the best? Why? Go to the BB discussion tab and answer this question. Respond as others answer. How could it be used to foster communication? Now check ...

Nunes-Bufford, Mrs.

2010-10-27

253

Terrestrial isopods -- a good choice for toxicity testing of pollutants in the terrestrial environment  

Microsoft Academic Search

Terrestrial isopods are suitable invertebrates for testing the relative toxicities of chemicals present in the terrestrial environment. Terrestrial isopods respond in numerous ways to elevated concentrations of chemicals in their food, but only a few of these responses can be used as toxicological endpoints. The most suitable are changes in reproduction, food consumption, moult cycle duration, and structure of the

Damjana Drobne

1997-01-01

254

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)

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.

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

2012-12-01

255

A robust TEC depletion detector algorithm for satellite based navigation in Indian zone and depletion analysis for GAGAN  

NASA Astrophysics Data System (ADS)

Equatorial plasma bubble (EPB) and associated plasma irregularities are known to cause severe scintillation for the satellite signals and produce range errors, which eventually result either in loss of lock of the signal or in random fluctuation in TEC, respectively, affecting precise positioning and navigation solutions. The EPBs manifest as sudden reduction in line of sight TEC, which are more often called TEC depletions, and are spread over thousands of km in meridional direction and a few hundred km in zonal direction. They change shape and size while drifting from one longitude to another in nighttime ionosphere. For a satellite based navigation system, like GAGAN in India that depends upon (i) multiple satellites (i.e. GPS) (ii) multiple ground reference stations and (iii) a near real time data processing, such EPBs are of grave concern. A TEC model generally provides a near real-time grid based ionospheric vertical errors (GIVEs) over hypothetically spread 5x5 degree latitude-longitude grid points. But, on night when a TEC depletion occurs in a given longitude sector, it is almost impossible for any system to give a forecast of GIVEs. If loss-of-lock events occur due to scintillation, there is no way to improve the situation. But, when large and random depletions in TEC occur with scintillations and without loss-of-lock, it affects low latitude TEC in two ways. (a) Multiple satellites show depleted TEC which may be very different from model-TEC values and hence the GIVE would be incorrect over various grid points (ii) the user may be affected by depletions which are not sampled by reference stations and hence interpolated GIVE within one square would be grossly erroneous. The most general solution (and the far most difficult as well) is having advance knowledge of spatio-temporal occurrence and precise magnitude of such depletions. While forecasting TEC depletions in spatio-temporal domain are a scientific challenge (as we show below), operational systems require an immediate solution to attack this problem. Hence, an alternative approach is chosen in which TEC-depletions are ignored for GIVE estimation. This approach requires further attention to accommodate it in the processing software for a near real time solution for the concerned user in Indian zone. But, nonetheless, as a prime concern, to precluding a particular satellite-link affected by TEC depletion, a reference receiver or user requires an algorithm that can compute the TEC and detect the depletion in TEC in near real time. To answer it, a novel TEC depletion detector algorithm and software has been developed which can be used for any SBAS in India. The algorithm is initially tested for recorded data from ground based dual frequency GPS receivers of GAGAN project. Data from 18-20 stations with 30 second sampling interval was obtained for year 2004 and 2005. The algorithm has been tuned to Indian ionosphere and show a great success in detecting TEC depletions with minimum false alarm. This is because of a specific property of this algorithm that it rejects the smooth fall in TEC in post sunset ionosphere. The depletions in TEC are characterized by a sudden fall and immediate recovery in level of TEC for a given line of sight. Since our algorithm extracts only such signatures and hence minimize the false alarms it may reduce burden on operational systems. We present this algorithm in detail. Another important facet of this algorithm is about its scientific use in automatic analysis of large amount of continuous GPS data. We have analyzed the aforementioned data by a MATLAB based script and obtained significant statistical results. The temporal duration and depth of TEC depletions is obtained for all over Indian region which provide a new insight over the phenomenon called EPBs and TEC depletions.

Dashora, Nirvikar

2012-07-01

256

Integrated estimates of global terrestrial carbon sequestration  

Microsoft Academic Search

Assessing the contribution of terrestrial carbon sequestration to climate change mitigation requires integration across scientific and disciplinary boundaries. A comprehensive analysis incorporating ecologic, geographic and economic data was used to develop terrestrial carbon sequestration estimates for agricultural soil carbon, reforestation and pasture management. These estimates were applied in the MiniCAM integrated assessment model to evaluate mitigation strategies within policy and

Allison M. Thomson; R. César Izaurralde; Steven J. Smith; Leon E. Clarke

2008-01-01

257

Aerospace Power Technology for Potential Terrestrial Applications  

NASA Technical Reports Server (NTRS)

Aerospace technology that is being developed for space and aeronautical applications has great potential for providing technical advances for terrestrial power systems. Some recent accomplishments arising from activities being pursued at the National Aeronautics and Space Administration (NASA) Centers is described in this paper. Possible terrestrial applications of the new aerospace technology are also discussed.

Lyons, Valerie J.

2012-01-01

258

Does terrestrial epidemiology apply to marine systems?  

Microsoft Academic Search

Most of epidemiological theory has been developed for terrestrial systems, but the significance of disease in the ocean is now being recognized. However, the extent to which terrestrial epidemiology can be directly trans- ferred to marine systems is uncertain. Many broad types of disease-causing organism occur both on land and in the sea, and it is clear that some emergent

Hamish I. McCallum; Armand Kuris; C. Drew Harvell; Kevin. D. Lafferty; Garriet W. Smith; James Porter

2004-01-01

259

Traumatic insemination in terrestrial arthropods.  

PubMed

Traumatic insemination is a bizarre form of mating practiced by some invertebrates in which males use hypodermic genitalia to penetrate their partner's body wall during copulation, frequently bypassing the female genital tract and ejaculating into their blood system. The requirements for traumatic insemination to evolve are stringent, yet surprisingly it has arisen multiple times within invertebrates. In terrestrial arthropods traumatic insemination is most prevalent in the true bug infraorder Cimicomorpha, where it has evolved independently at least three times. Traumatic insemination is thought to occur in the Strepsiptera and has recently been recorded in fruit fly and spider lineages. We review the putative selective pressures that may have led to the evolution of traumatic insemination across these lineages, as well as the pressures that continue to drive divergence in male and female reproductive morphology and behavior. Traumatic insemination mechanisms and attributes are compared across independent lineages. PMID:24160423

Tatarnic, Nikolai J; Cassis, Gerasimos; Siva-Jothy, Michael T

2014-01-01

260

Methane production in terrestrial arthropods.  

PubMed Central

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

Hackstein, J H; Stumm, C K

1994-01-01

261

Lunar and terrestrial crust formation  

NASA Astrophysics Data System (ADS)

Planetary crusts may be accreted, produced in primordial differentiation, or built up piecemeal by serial magmatism. The existence of old, polygenetic, laterally heterogeneous, partial melt rocks in the lunar highlands suggests that the moon produced its early crust by serial magmatism. This view can be reconciled with lunar Eu anomalies, previously thought to support the magma ocean model of crust formation, if complications in the fractionation of mare basalts are recognized. Phase equilibrium and magmatic density information for mare basalts suggest a model in which plagioclase fractionation can occur even though plagioclase is not a near-liquidus phase. The cryptic fractionation of clinopyroxene in MORB provides a precedent for this model. The necessity for a lunar magma ocean is questioned, but a role for a terrestrial magma ocean of sorts at depths is suggested.

Walker, D.

1983-11-01

262

Solar-Terrestrial Ontology Development  

NASA Astrophysics Data System (ADS)

The development of an interdisciplinary virtual observatory (the Virtual Solar-Terrestrial Observatory; VSTO) as a scalable environment for searching, integrating, and analyzing databases distributed over the Internet requires a higher level of semantic interoperability than here-to-fore required by most (if not all) distributed data systems or discipline specific virtual observatories. The formalization of semantics using ontologies and their encodings for the internet (e.g. OWL - the Web Ontology Language), as well as the use of accompanying tools, such as reasoning, inference and explanation, open up both a substantial leap in options for interoperability and in the need for formal development principles to guide ontology development and use within modern, multi-tiered network data environments. In this presentation, we outline the formal methodologies we utilize in the VSTO project, the currently developed use-cases, ontologies and their relation to existing ontologies (such as SWEET).

McGuinness, D.; Fox, P.; Middleton, D.; Garcia, J.; Cinquni, L.; West, P.; Darnell, J. A.; Benedict, J.

2005-12-01

263

Terrestrial gamma-ray flashes  

NASA Astrophysics Data System (ADS)

Lightning and thunderstorm systems in general have been recently recognized as powerful particle accelerators, capable of producing electrons, positrons, gamma-rays and neutrons with energies as high as several tens of MeV. In fact, these natural systems turn out to be the highest energy and most efficient natural particle accelerators on Earth. Terrestrial Gamma-ray Flashes (TGFs) are millisecond long, very intense bursts of gamma-rays and are one of the most intriguing manifestation of these natural accelerators. Only three currently operative missions are capable of detecting TGFs from space: the RHESSI, Fermi and AGILE satellites. In this paper we review the characteristics of TGFs, including energy spectrum, timing structure, beam geometry and correlation with lightning, and the basic principles of the associated production models. Then we focus on the recent AGILE discoveries concerning the high energy extension of the TGF spectrum up to 100 MeV, which is difficult to reconcile with current theoretical models.

Marisaldi, Martino; Fuschino, Fabio; Labanti, Claudio; Tavani, Marco; Argan, Andrea; Del Monte, Ettore; Longo, Francesco; Barbiellini, Guido; Giuliani, Andrea; Trois, Alessio; Bulgarelli, Andrea; Gianotti, Fulvio; Trifoglio, Massimo

2013-08-01

264

Line following terrestrial insect biobots.  

PubMed

The present day technology falls short in offering centimeter scale mobile robots that can function effectively under unknown and dynamic environmental conditions. Insects, on the other hand, exhibit an unmatched ability to navigate through a wide variety of environments and overcome perturbations by successfully maintaining control and stability. In this study, we use neural stimulation systems to wirelessly navigate cockroaches to follow lines to enable terrestrial insect biobots. We also propose a system-on-chip based ZigBee enabled wireless neurostimulation backpack system with on-board tissue-electrode bioelectrical coupling verification. Such a capability ensures an electrochemically safe stimulation and avoids irreversible damage to the interface which is often misinterpreted as habituation of the insect to the applied stimulation. PMID:23366056

Latif, Tahmid; Bozkurt, Alper

2012-01-01

265

Steroidal glycosides from Tribulus terrestris  

Microsoft Academic Search

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.

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

1996-01-01

266

Contrasting coloration in terrestrial mammals  

PubMed Central

Here I survey, collate and synthesize contrasting coloration in 5000 species of terrestrial mammals focusing on black and white pelage. After briefly reviewing alternative functional hypotheses for coloration in mammals, I examine nine colour patterns and combinations on different areas of the body and for each mammalian taxon to try to identify the most likely evolutionary drivers of contrasting coloration. Aposematism and perhaps conspecific signalling are the most consistent explanations for black and white pelage in mammals; background matching may explain white pelage. Evidence for contrasting coloration is being involved in crypsis through pattern blending, disruptive coloration or serving other functions, such as signalling dominance, lures, reducing eye glare or in temperature regulation has barely moved beyond anecdotal stages of investigation. Sexual dichromatism is limited in this taxon and its basis is unclear. Astonishingly, the functional significance of pelage coloration in most large charismatic black and white mammals that were new to science 150 years ago still remains a mystery.

Caro, Tim

2008-01-01

267

Speech Communication.  

ERIC Educational Resources Information Center

The communications approach to teaching speech to high school students views speech as the study of the communication process in order to develop an awareness of and a sensitivity to the variables that affect human interaction. In using this approach the student is encouraged to try out as many types of messages using as many techniques and…

Anderson, Betty

268

Communicator, 1997.  

ERIC Educational Resources Information Center

The CAG "Communicator" focus is on serving gifted students in California. This document consists of the four issues of "communicator" issued during 1997. Featured articles include: (1) "The Gifted Student At Risk. It Can't Be True" (Judy Roseberry); (2) "Tech Net-Technology and At-Risk Students" (Judy Lieb); (3) "Reviving Ophelia: Saving the…

Bortolussi, Vicki, Ed.

1997-01-01

269

Communicator, 1998.  

ERIC Educational Resources Information Center

The CAG "Communicator" focuses on serving gifted students in California. This document consists of the four issues of "Communicator" issued during 1998. Featured articles include: (1) "Underachievement for Some--Dropping Out with Dignity for Others" (Sally Reis); (2) "When Gifted High School Students Fail" (Patty Bort); (3) "Choosing a College"…

Bortolussi, Vicki, Ed.

1998-01-01

270

Intercultural Communication.  

ERIC Educational Resources Information Center

Human communication involves the interaction of selves, and an intercultural encounter permits the discovery of one's own cultural self. Participatory learning of intercultural communication provides students with an opportunity for involvement through analysis of their and others' perceptions, improvement of language fidelity, emphasis on…

Newmark, Eileen; Asante, Molefi K.

271

Terrestrial Ages of Antarctic Meteorites- Update 1999  

NASA Technical Reports Server (NTRS)

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-14 (1.04 x 10(exp 5) y) for terrestrial age determinations solves this problem by filling the c,ap in half-life between 14-C 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. We have measured Cl-36 in over 270 Antarctic meteorites since our previous compilation of terrestrial ages. Since a large number of meteorites have been recovered from many different icefields in Antarctica, we continue to survey the trends of terrestrial ages for different icefields. We have also measured detailed terrestrial ages vs. sample locations for Allan Hills, Elephant Moraine, and Lewis Cliff Icefields, where meteorites have been found with very long ages. The updated histograms of terrestrial ages of meteorites from the Allan Hills Main Icefield and Lewis Cliff Icefield are shown. These figures include C-14 ages obtained by the University of Arizona group. Pairs of meteorites are shown as one object for which the age is the average of all members of the same fall. The width of the bars represents 70,000 years, which was a typical uncertainty for Cl-36 ages. We reduced the uncertainty of terrestrial age determinations to approx. 40,000 years by using pairs of nuclides such as Ca-41-Cl-36 or Cl-36-Be-10. Meteorites found at the Allan Hills Icefields are much older than any other meteorites. The terrestrial ages cover a wide range and are as old as 2 My. Many of the Lewis Cliff meteorites are as old as the Allan Hills meteorites. So far, no clear correlation has been found between the terrestrial ages and the locations of the Lewis Cliff meteorites.

Nishiizumi, Kunihiko; Welten, K. C.; Caffee, Marc W.

1999-01-01

272

Communication: Are Australians Different?  

ERIC Educational Resources Information Center

Examines the question of the distinctive nature of communication in Australia. Discusses nonverbal messages, gender concerns, historical influences on communication, the Australian accent, communication with indigenous persons, communication apprehension, and classroom communication. Argues that Australians' communication is relatively similar to…

Hansford, B. C.

1992-01-01

273

Satellite-based analysis of evapotranspiration and water balance in the grassland ecosystems of Dryland East Asia.  

PubMed

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

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

274

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

PubMed Central

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.

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

275

The ORBCOMM data communications system  

NASA Technical Reports Server (NTRS)

The ORBCOMM system is designed to provide low-cost, two-way data communications for mobile and remote users. The communications system is ideally configured for low data rate applications where communicating devices are geographically dispersed and two-way communications through terrestrial means is cumbersome and not cost effective. The remote terminals use VHF frequencies which allow for the use of very small, low-cost terminals. ORBCOMM has entered into joint development agreements with several large manufacturers of both consumer and industrial electronics to design and build the remote terminals. Based on prototype work, the estimated retail cost of these units will range from $50 to $400 depending on the complexity of the design. Starting in the fall of 1993, ORBCOMM will begin service with a demonstration network consisting of two operating satellites. By the end of 1994, a full operating network of 26 satellites, four Gateway Earth Stations, and a Network Control Center will be in place. The full constellation will provide full coverage of the entire world with greater than 94 percent communications availability for the continental U.S. This paper describes the ORBCOMM system, the technology used in its implementation, and its applications.

Schoen, David C.; Locke, Paul A.

1993-01-01

276

Satellite-based monitoring of decadal soil salinization and climate effects in a semi-arid region of China  

NASA Astrophysics Data System (ADS)

Soil salinization is a common phenomenon that affects both the environment and the socio-economy in arid and semi-arid regions; it is also an important aspect of land cover change. In this study, we integrated multi-sensor remote sensing data with a field survey to analyze processes of soil salinization in a semi-arid area in China from 1979 to 2009. Generally, the area of salt-affected soils increased by 0.28% per year with remarkable acceleration from 1999 to 2009 (0.42% increase per year). In contrast, the area of surface water bodies showed a decreasing trend (-0.08% per year) in the same period. Decreases in precipitation and increases in aridity due to annual (especially summer) warming provided a favorable condition for soil salinization. The relatively flat terrain favored waterlogging at the surface, and continuous drought facilitated upward movement of soil water and accumulation of surface saline and calcium. Meanwhile, land-use practices also played a crucial role in accelerating soil salinization. The conversion to cropland from natural vegetation greatly increased the demand for groundwater irrigation and aggravated the process of soil salinization. Furthermore, there are potential feedbacks of soil salinization to regional climate. The salinization of soils can limit the efficiency of plant water use as well as photosynthesis; therefore, it reduces the amount of carbon sequestrated by terrestrial ecosystem. Soil salinization also reduces the absorbed solar radiation by increasing land surface albedo. Such conversions of land cover significantly change the energy and water balance between land and atmosphere.

Wang, Hesong; Jia, Gensuo

2012-09-01

277

Wireless Communications  

NASA Technical Reports Server (NTRS)

A technology utilization project led to the commercial adaptation of a Space Shuttle Orbiter wireless infrared voice communications system. The technology was adapted to a LAN system by Wilton Industries, one of the participants. Because the system is cable-free, installation charges are saved, and it can be used where cable is impractical. Resultant products include the IRplex 6000. Transceivers can be located anywhere and can include mobile receivers. The system provides wireless LAN coverage up to 44,000 square feet. applications include stock exchange communications, trade shows, emergency communications, etc.

1991-01-01

278

A Study on Atmospheric Turbulence Effects in Full-Optical Free-Space Communication Systems  

Microsoft Academic Search

Next generation free-space optical communication systems have used fiber-optic technology as the seamless connection between free-space and optical fiber. The full-optical free-space optical communication systems use optical fiber as the receiver to get faster communication speed. The atmospheric turbulence deeply influenced on the optical wave propagated in terrestrial application. As the active receiving area of the full-optical free-space optical communication

Xueying Wu; Peng Liu; Mitsuji Matsumoto

2010-01-01

279

Acoustic Communication  

NSDL National Science Digital Library

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.

0002-11-30

280

Solar-terrestrial models and application software  

NASA Technical Reports Server (NTRS)

The empirical models related to solar-terrestrial sciences are listed and described which are available in the form of computer programs. Also included are programs that use one or more of these models for application specific purposes. The entries are grouped according to the region of the solar-terrestrial environment to which they belong and according to the parameter which they describe. Regions considered include the ionosphere, atmosphere, magnetosphere, planets, interplanetary space, and heliosphere. Also provided is the information on the accessibility for solar-terrestrial models to specify the magnetic and solar activity conditions.

Bilitza, Dieter

1990-01-01

281

Solar Terrestrial Physics: Present and Future  

NASA Technical Reports Server (NTRS)

The following topics relating to solar-terrestrial interactions are considered: (1) reconnection of magnetic fields; (2) particle acceleration; (3) solar magnetic flux; (4) magnetohydrodynamic waves and turbulence in the Sun and interplanetary medium; (5) coupling of the solar wind to the magnetosphere; (6) coronal transients; (7) the connection between the magnetosphere and ionosphere; (8) substorms in the magnetosphere; (9) solar flares and the solar terrestrial environment; (10) shock waves in the solar terrestrial environment; (11) plasma transport and convection at high latitudes; and (12) high latitude ionospheric structure.

Butler, D. M. (editor); Papadopoulos, K. (editor)

1984-01-01

282

Serial Communications  

Microsoft Academic Search

Introduce the RS232 standard and position it within the crowded field of serial communications standards. Configure the 8051\\u000a serial port. Read and write to the serial port. Introduce software and hardware handshaking.\\u000a \\u000a This chapter is a fast-paced introduction to RS232 serial communications. Unlike other books that start with a history lesson,\\u000a this one will present material as it is needed

Kai Qian; David Haring; Li Cao

283

Wireless Communication  

NSDL National Science Digital Library

This quicktime animation examines the basics in wireless communication. Wireless communication has become pervasive in everyday life, providing convenience, piece of mind as well as emergency preparedness for its users through instant accessibility. The cell phone antenna is the link to the outside world. Designed to transmit as well as receive the RF signals, it efficiently couples the electromagnetic waves to the transmitter and receiver.

Van Zeghbroeck, Bart J.

2012-08-08

284

47 CFR 25.149 - Application requirements for ancillary terrestrial components in the Mobile-Satellite Service...  

Code of Federal Regulations, 2013 CFR

...terrestrial components in the Mobile-Satellite Service networks operating in the 1...1.6/2.4 GHz and 2 GHz Mobile-Satellite Service. 25.149 Section 25.149...CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and...

2013-10-01

285

47 CFR 25.149 - Application requirements for ancillary terrestrial components in the mobile-satellite service...  

Code of Federal Regulations, 2010 CFR

...terrestrial components in the mobile-satellite service networks operating in the 1...1.6/2.4 GHz and 2 GHz mobile-satellite service. 25.149 Section 25.149...CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and...

2010-10-01

286

47 CFR 25.149 - Application requirements for ancillary terrestrial components in the mobile-satellite service...  

Code of Federal Regulations, 2010 CFR

...terrestrial components in the mobile-satellite service networks operating in the 1...1.6/2.4 GHz and 2 GHz mobile-satellite service. 25.149 Section 25.149...CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and...

2009-10-01

287

Terrestrial Energy Storage SPS Systems  

NASA Technical Reports Server (NTRS)

Terrestrial energy storage systems for the SSP system were evaluated that could maintain the 1.2 GW power level during periods of brief outages from the solar powered satellite (SPS). Short-term outages of ten minutes and long-term outages up to four hours have been identified as "typical" cases where the ground-based energy storage system would be required to supply power to the grid. These brief interruptions in transmission could result from performing maintenance on the solar power satellite or from safety considerations necessitating the power beam be turned off. For example, one situation would be to allow for the safe passage of airplanes through the space occupied by the beam. Under these conditions, the energy storage system needs to be capable of storing 200 MW-hrs and 4.8 GW-hrs, respectively. The types of energy storage systems to be considered include compressed air energy storage, inertial energy storage, electrochemical energy storage, superconducting magnetic energy storage, and pumped hydro energy storage. For each of these technologies, the state-of-the-art in terms of energy and power densities were identified as well as the potential for scaling to the size systems required by the SSP system. Other issues addressed included the performance, life expectancy, cost, and necessary infrastructure and site locations for the various storage technologies.

Brandhorst, Henry W., Jr.

1998-01-01

288

Terrestrial Planet Finder: science overview  

NASA Technical Reports Server (NTRS)

The Terrestrial Planet Finder (TPF) seeks to revolutionize our understanding of humanity's place in the universe - by searching for Earth-like planets using reflected light, or thermal emission in the mid-infrared. Direct detection implies that TPF must separate planet light from glare of the nearby star, a technical challenge which has only in recent years been recognized as surmountable. TPF will obtain a low-resolution spectra of each planets it detects, providing some of its basic physical characteristics and its main atmospheric constituents, thereby allowing us to assess the likelihood that habitable conditions exist there. NASA has decided the scientific importance of this research is so high that TPF will be pursued as two complementary space observatories: a visible-light coronagraph and a mid-infrared formation flying interferometer. The combination of spectra from both wavebands is much more valuable than either taken separately, and it will allow a much fuller understanding of the wide diversity of planetary atmospheres that may be expected to exist. Measurements across a broad wavelength range will yield not only physical properties such as size and albedo, but will also serve as the foundations of a reliable and robust assessment of habitability and the presence of life.

Unwin, Stephen C.; Beichman, C. A.

2004-01-01

289

Bibliography of terrestrial impact structures  

NASA Technical Reports Server (NTRS)

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.

Grolier, M. J.

1985-01-01

290

Steroidal saponins from Tribulus terrestris.  

PubMed

Five new steroidal saponins were isolated from the fruits of Tribulus terrestris. Their structures were fully established by spectroscopic and chemical analysis as (23S,25S)-5alpha-spirostane-24-one-3beta,23-diol-3-O-{alpha-l-rhamnopyranosyl-(1-->2)-O-[beta-d-glucopyranosyl-(1-->4)]-beta-d-galactopyranoside} (1), (24S,25S)-5alpha-spirostane-3beta,24-diol-3-O-{alpha-l-rhamnopyranosyl-(1-->2)-O-[beta-d-glucopyranosyl-(1-->4)]-beta-d-galactopyranoside} (2), 26-O-beta-d-glucopyranosyl-(25R)-5alpha-furostan-2alpha,3beta,22alpha,26-tetraol-3-O-{beta-d-glucopyranosyl-(1-->2)-O-beta-d-glucopyranosyl-(1-->4)-beta-d-galactopyranoside} (3), 26-O-beta-d-glucopyranosyl-(25R)-5alpha-furostan-20(22)-en-2alpha,3beta,26-triol-3-O-{beta-d-glucopyranosyl-(1-->2)-O-beta-d-glucopyranosyl-(1-->4)-beta-d-galactopyranoside} (4), and 26-O-beta-d-glucopyranosyl-(25S)-5alpha-furostan-12-one-22-methoxy-3beta,26-diol-3-O-{alpha-l-rhamnopyranosyl-(1-->2)-O-[beta-d-glucopyranosyl-(1-->4)]-beta-d-galactopyranoside} (5). The isolated compounds were evaluated for cytostatic activity against HL-60 cells. PMID:19152803

Su, Lan; Chen, Gang; Feng, Sheng-Guang; Wang, Wei; Li, Zhi-Feng; Chen, Huan; Liu, Ying-Xue; Pei, Yue-Hu

2009-01-01

291

Use of communications. [satellite communication  

NASA Technical Reports Server (NTRS)

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.

1975-01-01

292

Incorporation of Disturbance and Seasonality in Terrestrial Carbon Flux Upscaling  

NASA Astrophysics Data System (ADS)

Integration of disturbance patterns into carbon (C) flux estimates to improve terrestrial-atmosphere C exchange is a critical priority for the North American Carbon Program. This project is built upon previous findings from The Chequamegon Ecosystem Atmospheric Study and aims to quantify uncertainty in C flux upscaling due to disturbance and seasonality, evaluate multiple disturbance stressors, and develop two-way communication channels between federal agencies and scientists. This project asks three main questions: (1) Does incorporation of disturbance processes and seasonally varying model parameter values improve yearly to decadal CO2 flux hindcasts from eddy flux towers? (2) Does incorporation of hydrologic processes improve CO2 flux hindcasts from eddy flux towers? and (3) To what degree does model-data integration aid regional and landscape decision-making for forest C storage management? We show that parameter and prediction uncertainty in terrestrial C fluxes increases with increasing stand age with a slight decline at the end of the stand age spectrum (old stands). Additionally, categorizing landscape into age since disturbance and/or disturbance type (eg., clear-cut, partial disturbance, undisturbed) significantly influence C fluxes and associated uncertainty. The finding from this project directly contribute to national efforts to constrain uncertainty in terrestrial-atmospheric C exchange in several important ways. First, it utilizes new disturbance algorithms using Landsat imagery to test whether inclusion of partial and stand-replacing disturbance reduces uncertainty in C flux upscaling. Second, it employs a computationally tractable but responsive photosynthetic model to evaluate whether including remotely sensed hydrology data aids in diagnosis of interannual C flux estimates. Third, by collaborating with regional and national Forest Service personnel, this project partially addresses the 'end-to-end' problem of C cycle science by helping managers to diagnose adaptive capacity of forested landscapes, target locations where the C balance is sensitive to management choices, and prioritize C management activities.

Naithani, K. J.; Baldwin, D. C.; Smithwick, E. A.; Davis, K. J.; Keller, K.; Kennedy, R. E.; Masek, J. G.

2012-12-01

293

The solar photon thruster as a terrestrial pole sitter.  

PubMed

Geosynchronous satellites are invisible at high latitudes. A pole-sitting spacecraft would have communication, climate-studies, and near-polar Earth observation applications. We present a pole-sitter based on the solar photon thruster (SPT), a two-sail variant of the solar sail using a large curved collector sail (always normal to the Sun) to direct sunlight against a much smaller thruster. Thrust decreases slower for an SPT than for a conventional sail arrangement as the angle between sunlight and the collector normal increases. An SPT pole-sitter is offset from the terrestrial pole so that a component of Earth gravity balances the solar radiation-pressure component pushing the SPT off station. The component of gravitational attraction of the Earth pulling the spacecraft towards Earth is also balanced by a solar radiation-pressure component. Results are presented for 80-100% collector/thruster reflectivities. For a spacecraft areal mass thickness of 0.002 kg/m(2), collector and thruster reflectivities of 0.9, the SPT can be situated above latitude 45 degrees at a distance of approximately 60 Earth radii. An SPT pole sitter would be affected by lunar perturbation, which can be compensated for by an on-board rocket thruster producing 2 x 10(-6) g acceleration, a second SPT thruster sail thrusting against the influence of the Moon, or by directing a microwave beam against the spacecraft. Since an SPT pole sitter is in a position rather than an orbit, the effect of terrestrial gravitation limits the size and design of the payload package, which limits terrestrial target resolution. PMID:15220163

Matloff, Gregory L

2004-05-01

294

Influence of the Qinghai-Tibetan railway on the habitat selection of wild animals, using satellite data and satellite-based ARGOS system data  

NASA Astrophysics Data System (ADS)

The Qinghai-Tibet Railway (QTR) was in trial operation since 1 July 2006, is the world's highest-elevation railway and the longest highland railway, extending over 1956 km from Xining (Qinghai's capital in northwestern China) to Lhasa, the capital city of the Tibet Autonomous Region. This QTR railway was crosses five nature reserves along the route Hoh Xil (COCOX- ILI), Qinghai Sanjiangyuan, Chang Tang, Lin-chou Pengbo, and La-lu, and Hoh xil nature reserve is the important breeding sites of Tibetan Antelope (Pantholops hodgsoni). In order to clearly the habitat use and habitat selection of the Tibetan Antelope was divided in the north and south by the QTR railway, we planned the capture of ten Tibetan Antelopes and attach a satellite-based ARGOS system platform transmitter terminal (PTT) to the Tibetan Antelopes. And we succeeded in the capture of two Tibetan Antelopes for the first time in the world in 2007a summer and attached an ARGOS PTT. In this study, we estimate RASTER model of habitat change, using satellite-based ARGOS PTT tracking analyst data and satellite (Terra/MODIS, Terra/ASTER, ALOS and SPOT/vegetation instrument data) land cover change data, order to clearly the spatial and temporal characteristics of wide area habitat selection of Tibetan Antelope.

Buhe, Aosier

295

Feasibility Study of Short-Term Storm Forecasting Over the Gulf of Mexico by Blending Satellite-Based Extrapolation Forecasts with Numerical Weather Prediction Results  

NASA Astrophysics Data System (ADS)

Deep convection over the ocean poses a potentially great danger for trans-oceanic flights, as tragically demonstrated by the Air France Flight 447 accident of 2009. This paper describes a forecasting system that will produce 0-12 hr convective forecasts over the Gulf of Mexico domain using a blending technique that combines satellite-based extrapolation forecasts with Numerical Weather Prediction (NWP) model forecasts. Closely following the steps of the Federal Aviation Administration (FAA) Aviation Weather Research Program (AWRP) CoSPA development, a forecasting system is being developed to blend satellite-derived rain rate and cloud top height with their corresponding fields derived from the Global Forecasting System (GFS) NWP model. Forecasts will be computed over the 0-12 hr time frame within a domain that encompasses the greater Gulf of Mexico and parts of the continental United States. Tests of various extrapolation techniques have been completed and an optimum technique has been selected. Both the extrapolated and the GFS rain rate forecast performance statistics have been compiled. Considering the relative strength of the NWP model and the satellite-based extrapolation forecasts, a dynamical-weighting technique, similar to what is being used in CoSPA, has been tested. The weights are determined by past performance of extrapolation and model forecasts as a function of forecast lead time. A prototype blended forecasting system for oceanic convection using dynamical-weighting techniques has been developed and preliminary results of the blended forecasting system will be reported at the conference.

Cai, H.; Kessinger, C.; Rehak, N.; Pinto, J. O.; Megenhardt, D.; Albo, D.; Phillips, C.; Bankert, R.; Hawkins, J.

2012-12-01

296

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)

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.

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

2011-02-01

297

OASYS laser radar characterization of natural and manmade terrestrial features  

NASA Astrophysics Data System (ADS)

Performance of the Northrop Grumman Obstacle Avoidance Laser Radar System (OASYS) has been characterized against various terrestrial targets. OASYS is capable of discriminating and identifying objects from a complementary background as well as producing high-resolution laser radar imagery. Its primary function alerts pilots to obstacles in a helicopter flight path; thus, allowing evasive maneuvers to be performed to avoid collision. Primary obstacles encountered are: (1) wires; (2) trees; (3) transmission towers; (4) vertical poles; (5) structures, and; (6) terrain. Of these, wires are the most difficult to detect due to their small cross section. A simple, but very effective object identification algorithm is utilized which unerringly communicates large volumes of detected object data to the pilot, or to the recording computer for later analysis. In the program reported here, laser radar images of various terrestrial objects were obtained and their properties measured. In this manner a database of object signatures, cross-sections, and images is obtained. These objects include: (1) wires of various diameter and reflectivity; (2) trees and vegetation; (3) large and small vertical objects including transmission towers and poles; (4) buildings and structures, and (5) various terrain types.

Grasso, Robert J.; Pratty, Adam C. P.; Vann, Christopher M.; Stimson, Clinton G.; Ackleson, James E.

1999-12-01

298

Transfer of terrestrial technology for lunar mining  

NASA Technical Reports Server (NTRS)

The functions, operational procedures, and major items of equipment that comprise the terrestrial mining process are characterized. These data are used to synthesize a similar activity on the lunar surface. Functions, operations, and types of equipment that can be suitably transferred to lunar operation are identified. Shortfalls, enhancements, and technology development needs are described. The lunar mining process and what is required to adapt terrestrial equipment are highlighted. It is concluded that translation of terrestrial mining equipment and operational processes to perform similar functions on the lunar surface is practical. Adequate attention must be given to the harsh environment and logistical constraints of the lunar setting. By using earth-based equipment as a forcing function, near- and long-term benefits are derived (i.e., improved terrestrial mining in the near term vis-a-vis commercial production of helium-3 in the long term.

Hall, Robert A.; Green, Patricia A.

1992-01-01

299

New Pest Response Guidelines: Temperate Terrestrial Gastropods.  

National Technical Information Service (NTIS)

Use New Pest Response Guidelines: Temperate Terrestrial Gastropods as a guide when designing a program to detect, monitor, control, contain, or eradicate an infestation of temperate climate pest snails and slugs in the United States and collaborating terr...

2008-01-01

300

Space Vehicle Terrestrial Environment Design Requirements Guidelines  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

301

The geology of the terrestrial planets  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

302

AIR POLLUTION EFFECTS ON TERRESTRIAL ECOSYSTEMS  

EPA Science Inventory

This report presents information on the effects of ozone, nitrogen oxides, sulfur oxides, particulate matter, and acidic disposition on terrestrial ecosystems. A brief explanation of ecosystem dynamics is presented to provide a framework for discussion of air pollutant effects. D...

303

Data Base of Terrestrial Impact Structures  

NSDL National Science Digital Library

Database of Terrestrial Impact Structures leads to Natural Resources Canada's interactive global database of impact structures, complete with photographs and summary information. For those interested in learning more about Impact Craters, this is a fine starting point.

1997-01-01

304

DEVELOPMENT OF SCALING CRITERIA FOR TERRESTRIAL MICROCOSMS  

EPA Science Inventory

Theoretical developments based on heat and moisture transfer in soil lead to dimensionless numbers that describe important processes taking place in a terrestrial microcosm. These numbers provide preliminary scientific criteria for scaling the results from microcosms both as a me...

305

Project Universe - Local area networks and satellite communications  

NASA Astrophysics Data System (ADS)

A high-speed digital communications system is discussed in which a satellite is used to link a number of local area networks which interconnect a variety of computer facilities. The advantages of satellite communications compared with terrestrial links are described, together with a historical survey of the use of the Orbital Test Satellite (OTS) for data experiments. A description of Project Universe is given and the purpose of the project is described along with a more detailed description of the elements that make up the network such as satellite earth terminals, communication rings and terrestrial links. Future developments of such systems and their use as a means of business communication are considered, in particular, the factors affecting their growth, emphasis being placed on the specification and cost of equipment.

Ackroyd, B. R.

1983-07-01

306

Global Change and the Terrestrial Biosphere  

SciTech Connect

Terrestrial ecosystems sustain life on Earth through the production of food, fuel, fiber, clean air, and naturally purified water. But how will agriculture and ecosystems be affected by global change? Rogers describes the impact of projected climate change on the terrestrial biosphere and explains why plants are not just passive respondents to global change, but play an important role in determining the rate of change.

Alistair Rogers

2009-04-22

307

Application of the Iridium Satellite System to Aeronautical Communications  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

308

Satellite-aided land mobile communications system implementation considerations  

NASA Technical Reports Server (NTRS)

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

Leroy, B. E.

1982-01-01

309

Communicating Science  

NASA Astrophysics Data System (ADS)

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.

Holland, G. J.; McCaffrey, M. S.; Kiehl, J. T.; Schmidt, C.

2010-12-01

310

Update on terrestrial ages of Antarctic meteorites  

SciTech Connect

Terrestrial ages of Antarctic meteorites are one of the few parameters that will help us to understand the meteorite concentration mechanism on blue-ice fields. Traditionally, terrestrial ages were determined on the basis of {sup 36}Cl in the metal phase, which has an uncertainty of about 70 ky. For young meteorites (< 40 ky), the terrestrial age is usually and most accurately determined using {sup 14}C in the stone phase. In recent years two methods have been developed which are independent of shielding effects, the {sup 10}Be-{sup 36}Cl/{sup 10}Be method and the {sup 41}Ca/{sup 36}Cl method. These methods have reduced the typical uncertainties in terrestrial ages by a factor of 2, to about 30 ky. The {sup 10}Be-{sup 36}Cl/{sup 10}Be method is quite dependent on the exposure age, which is unknown for most Antarctic meteorites. The authors therefore also attempt to use the relation between {sup 26}Al and {sup 36}Cl/{sup 26}Al to derive a terrestrial age less dependent on the exposure age. The authors have measured the concentrations of cosmogenic {sup 10}Be, {sup 26}Al and {sup 36}Cl in the metal phase of {approximately} 70 Antarctic meteorites, from more than 10 different ice-fields, including many new ones. They then discuss the trends in terrestrial ages of meteorites from different ice-fields.

Welten, K C; Nishiizumi, K; Caffee, M W

2000-01-14

311

Combining Satellite-Based Precipitation and Vegetation Indices to Achieve a Mid-Summer Agricultural Forecast in Jamaica  

NASA Astrophysics Data System (ADS)

In this study global Earth observations of precipitation and Normalized Difference Vegetation Indices (NDVI) are used to assess the mid-summer dry spell’s (MSD) strength and subsequent impact on agriculture in the St. Elizabeth parish of Jamaica. St. Elizabeth is known as the ‘bread basket’ of Jamaica and has been the top or second highest producer of domestic food crops in the last twenty years. Yet, St. Elizabeth sits in the Jamaican rain shadow and is highly affected by drought. In addition, the summer rainy season is regularly interrupted by an MSD, which often occurs in July, has strong interannual variability, and greatly affects cropping strategies and yields. The steps undertaken to achieve a mid-summer agricultural forecast are: 1) use relationships between Global Precipitation Climatology Project v2.1 data over western Jamaica and predictive climate modes from 1979 to present to develop a forecast of July rainfall 2) downscale the rainfall variability in time to sub-monthly and space to the St. Elizabeth parish using the Tropical Rainfall Measuring Mission 3) link rainfall variability to vegetation vigor with the MODIS NDVI data 4) communicate with St. Elizabeth farmers via the University of West Indies, Mona. An important finding from this study is a decrease in vegetative vigor follows the MSD by two to four weeks in St. Elizabeth and the vegetation in the southern portion of the parish appears to be more sensitive to the MSD than vegetation elsewhere in the country.

Curtis, S.; Allen, T. L.; Gamble, D.

2009-12-01

312

Crisis Communication: The Business Communicator's Strategies for Communicating under Stress.  

ERIC Educational Resources Information Center

Uses the 1979 Three Mile Island nuclear plant accident to illustrate the communication problems embedded in a crisis. Describes the reactions created by the stress related to crisis. Suggests business communication strategies for improving communication to the public. (SR)

Vielhaber, Mary E.

1990-01-01

313

Groundwater and Terrestrial Water Storage  

NASA Technical Reports Server (NTRS)

Most people think of groundwater as a resource, but it is also a useful indicator of climate variability and human impacts on the environment. Groundwater storage varies slowly relative to other non-frozen components of the water cycle, encapsulating long period variations and trends in surface meteorology. On seasonal to interannual timescales, groundwater is as dynamic as soil moisture, and it has been shown that groundwater storage changes have contributed to sea level variations. Groundwater monitoring well measurements are too sporadic and poorly assembled outside of the United States and a few other nations to permit direct global assessment of groundwater variability. However, observational estimates of terrestrial water storage (TWS) variations from the GRACE satellites largely represent groundwater storage variations on an interannual basis, save for high latitude/altitude (dominated by snow and ice) and wet tropical (surface water) regions. A figure maps changes in mean annual TWS from 2009 to 2010, based on GRACE, reflecting hydroclimatic conditions in 2010. Severe droughts impacted Russia and the Amazon, and drier than normal weather also affected the Indochinese peninsula, parts of central and southern Africa, and western Australia. Groundwater depletion continued in northern India, while heavy rains in California helped to replenish aquifers that have been depleted by drought and withdrawals for irrigation, though they are still below normal levels. Droughts in northern Argentina and western China similarly abated. Wet weather raised aquifer levels broadly across western Europe. Rains in eastern Australia caused flooding to the north and helped to mitigate a decade long drought in the south. Significant reductions in TWS seen in the coast of Alaska and the Patagonian Andes represent ongoing glacier melt, not groundwater depletion. Figures plot time series of zonal mean and global GRACE derived non-seasonal TWS anomalies (deviation from the mean of each month of the year) excluding Greenland and Antarctica. The two figures show that 2010 was the driest year since 2003. The drought in the Amazon was largely responsible, but an excess of water in 2009 seems to have buffered that drought to some extent. The drying trend in the 25-55 deg S zone is a combination of Patagonian glacier melt and drought in parts of Australia.

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

2011-01-01

314

Formation of the terrestrial planets  

NASA Astrophysics Data System (ADS)

The early phases of formation in the inner solar system were dominated by collisions and short-range dynamical interactions among planetesimals. But the later phases, which account for most of the differences among planets, are unsure because the dynamics are more subtle. Jupiter's influence became more important, leading to drastic clearing out of the asteroid belt and the stunting of Mars's growth. Further in, the effect of Jupiter-- both directly and indirectly, through ejection of mass in the outer solar system-- was probably to speed up the process without greatly affecting the outcome. The great variety in bulk properties of the terrestrial bodies indicate a terminal phase of great collisions, so that the outcome is the result of small-N statistics. Mercury, 65 percent iron, appears to be a residual core from a high-velocity collision. All planets appear to require a late phase of high energy impacts to erode their atmospheres: including the Earth, to remove CO2 so that its ocean could form by condensation of water. Consistent with this model is that the largest collision, about 0.2 Earth masses, was into the proto-Earth, although the only property that appears to require it is the great lack of iron in the Moon. The other large differences between the Earth and Venus, angular momentum (spin plus satellite) and inert gas abundances, must arise from origin circumstances, but neither require nor forbid the giant impact. Venus's higher ratio of light to heavy inert gases argues for it receiving a large icy impactor, about 10-6 Earth masses from far out, requiring some improbable dynamics to get a low enough approach velocity. Core formation in both planets probably started rather early during accretion. Some geochemical evidences argue for the Moon coming from the Earth's mantle, but are inconclusive. Large scale melting of the mantle by the giant impact would plausibly have led to stratification. But the "lock-up" at the end of turbulent mantle convection is a trade-off between rates: crystallization of constituents of small density difference versus overall freezing. Also, factors such as differences in melting temperatures and densities, melt compressibilities, and phase transitions may have had homogenizing effects in the subsequent mantle convection.

Kaula, William M.

1994-01-01

315

Wireless communications from high altitude platforms: Applications, deployment and development  

Microsoft Academic Search

In this paper, an overview of the HAP concept development and HAP trails is introduced to show the worldwide interest and development in the emerging novel technology. A comparison of the HAP, terrestrial and satellite system characteristics is given. Main advantages of HAPs for wireless communication applications are large coverage area, high capacity and cost-effective deployment. Three applicable scenarios of

Z. Yang; A. Mohammed

2010-01-01

316

Broadband communications via high-altitude platforms: A survey  

Microsoft Academic Search

This article is a survey on communication aspects of High Altitude Platforms (HAPs), namely airships or aircraft positioned in the stratosphere between 17 and 22 km. HAPs can be considered as a novel solution for providing telecommunications services. This survey begins with an introduction to HAPs, that is, some historical information and advantages of HAPs compared to terrestrial and satellite

Stylianos Karapantazis; Fotini-niovi Pavlidou

2005-01-01

317

Nationwide mobile communication systems, volume 1, chapters 1 thru 4  

Microsoft Academic Search

This thesis provides a basic understanding of nationwide terrestrial and satellite mobile communications and tracking technologies. Covered are systems currently available and in development. An analysis of user costs is performed for comparison. A more detailed satellite cost\\/benefit analysis for use by the trucking industry is also presented. Follow-on chapters contain discussions of the basic economic issues faces by satellite

William Joseph Schworer III

1990-01-01

318

Magnetostatic communication  

DOEpatents

A system for providing communication of information by modulating a magnetostatic field with a magnetostatic transmitter that modulates said magnetostatic field to contain the information and detecting the information in the modulated field at a distance with a magnetostatic detector that detects the modulated magnetic field containing the information.

Daily, William D. (Livermore, CA) [Livermore, CA

2008-02-26

319

Communication Scheduling  

Microsoft Academic Search

The high arithmetic rates of media processing applications require architectures with tens to hundreds of functional units, multiple register files, and explicit interconnect between functional units and register files. Communication scheduling enables scheduling to these emerging architectures, including those that use shared buses and register file ports. Scheduling to these shared interconnect architectures is difficult because it requires simultaneously allocating

Peter R. Mattson; William J. Dally; Scott Rixner; Ujval J. Kapasi; John D. Owens

2000-01-01

320

49. Communication  

NSDL National Science Digital Library

This half-hour video includes 18 classroom excerpts from classroom lessons which show students representing, discussing, reading, writing, and listening as vital parts of learning and using mathematics. It shows how communication that arises naturally from rich tasks and experiences fosters understanding of mathematical concepts and development of mathematical language.

Cadwallader, Lynn

2013-01-01

321

Communication Education.  

ERIC Educational Resources Information Center

Intended for use by teachers of kindergarten through grade 10, this curriculum guide is designed to make communication education an integral part of the school program. The philosophy of the guide focuses on the processes of analyzing, formulating a position, and organizing information or ideas into meaningful form, rather than solely on surface…

Summit School District RE-1, Frisco, CO.

322

Communications technology  

NASA Technical Reports Server (NTRS)

The objective of the Communications Technology Program is to enable data transmission to and from low Earth orbit, geostationary orbit, and solar and deep space missions. This can be achieved by maintaining an effective, balances effort in basic, applied, and demonstration prototype communications technology through work in theory, experimentation, and components. The program consists of three major research and development discipline areas which are: microwave and millimeter wave tube components; solid state monolithic integrated circuit; and free space laser communications components and devices. The research ranges from basic research in surface physics (to study the mechanisms of surface degradation from under high temperature and voltage operating conditions which impacts cathode tube reliability and lifetime) to generic research on the dynamics of electron beams and circuits (for exploitation in various micro- and millimeter wave tube devices). Work is also performed on advanced III-V semiconductor materials and devices for use in monolithic integrated analog circuits (used in adaptive, programmable phased arrays for microwave antenna feeds and receivers) - on the use of electromagnetic theory in antennas and on technology necessary for eventual employment of lasers for free space communications for future low earth, geostationary, and deep space missions requiring high data rates with corresponding directivity and reliability.

Sokoloski, Martin M.

1988-01-01

323

Communications Electronics.  

ERIC Educational Resources Information Center

This module is the third in a series of electronics publications and serves as a supplement to "General Electronics Technician." It is designed to provide students with an overview of the broad field of communications. Included are those tasks above the basic skills level that allow students to progress to a higher level of competency in the…

Vorderstrasse, Ron; Siebert, Leo

324

Communicator, 1999.  

ERIC Educational Resources Information Center

These four 1999 issues of the "Communicator" address reading needs of gifted children, middle schools, parenting the gifted, and the needs of young gifted children. Featured articles include: (1) "Academic Advocacy for the Forgotten Readers--Gifted and Advanced Learners" (Reading Task Force of the California Association for the Gifted); (2)…

Gosfield, Margaret, Ed.

1999-01-01

325

Core Communications  

ERIC Educational Resources Information Center

The website--it is where people go to find out anything and everything about a school, college, or university. In the relatively short life of the Internet, institutional websites have moved from the periphery to center stage and become strategically integral communications and marketing tools. As the flow of information accelerates and new…

Block, Greg; Ross, J. D.; Mulder, David

2011-01-01

326

Communication Planning.  

ERIC Educational Resources Information Center

Communication planning in developing countries is discussed in individual articles on theory, knowledge production and utilization, planning at the regional level, software, and rural development. A nutrition education project and three experiments in developing educational materials with feedback from villagers in Africa are described in the…

Development Communication Report, 1978

1978-01-01

327

Communications protocol  

NASA Technical Reports Server (NTRS)

The present invention relates to an improved communications protocol which increases the efficiency of transmission in return channels on a multi-channel slotted Alohas system by incorporating advanced error correction algorithms, selective retransmission protocols and the use of reserved channels to satisfy the retransmission requests.

Zhou, Xiaoming (Inventor); Baras, John S. (Inventor)

2010-01-01

328

Communicating Science  

NASA Astrophysics Data System (ADS)

Introduction: what this book is about and why you might want to read it; Prologue: three orphans share a common paternity: professional science communication, popular journalism, and literary fiction are not as separate as they seem; Part I. Professional Science Communication: 1. Spreading the word: the endless struggle to publish professional science; 2. Walk like an Egyptian: the alien feeling of professional science writing; 3. The future's bright? Professional science communication in the age of the internet; 4. Counting the horse's teeth: professional standards in science's barter economy; 5. Separating the wheat from the chaff: peer review on trial; Part II. Science for the Public: What Science Do People Need and How Might They Get It?: 6. The Public Understanding of Science (PUS) movement and its problems; 7. Public engagement with science and technology (PEST): fine principle, difficult practice; 8. Citizen scientists? Democratic input into science policy; 9. Teaching and learning science in schools: implications for popular science communication; Part III. Popular Science Communication: The Press and Broadcasting: 10. What every scientist should know about mass media; 11. What every scientist should know about journalists; 12. The influence of new media; 13. How the media represents science; 14. How should science journalists behave?; Part IV. The Origins of Science in Cultural Context: Five Historic Dramas: 15. A terrible storm in Wittenberg: natural knowledge through sorcery and evil; 16. A terrible storm in the Mediterranean: controlling nature with white magic and religion; 17. Thieving magpies: the subtle art of false projecting; 18. Foolish virtuosi: natural philosophy emerges as a distinct discipline but many cannot take it seriously; 19. Is scientific knowledge 'true' or should it just be 'truthfully' deployed?; Part V. Science in Literature: 20. Science and the Gothic: the three big nineteenth-century monster stories; 21. Science fiction: serious literature of ideas or low-grade entertainment?; 22. Science in British literary fiction; 23. Science on stage: the politics and ethics of science in cultural and educational contexts.

Russell, Nicholas

2009-10-01

329

Supporting tools of solar-terrestrial science  

NASA Technical Reports Server (NTRS)

Solar-terrestrial science is pursued by individuals and teams of workers situated in academia, research institutes, industry, and government laboratories. Progress in the field is made in various ways, but publication of results in scientific journals is the principal means of assuring that the knowledge gained from research is available to the public, now and in the future. In general, much of the research in the field is made via careful evaluation of data viewed in the context of fundamental physical principles as set forth in theoretical and analytical models, and computer simulations of physical processes. In addition, there is accumulation of knowledge expressed in the development of empirical or phenomenological models. Experience gained over the past three decades of solar-terrestrial research indicated that advances in the field require a diversity of resources and that the health of the entire discipline depends upon a balance among these. To maintain the health of the discipline, NASA and other federal funding agencies concerned with solar-terrestrial research must work together to insure that the following resources are available in reasonable measure to support solar-terrestrial research endeavors: ground-based facilities; balloons and rockets; spaceborne experiments; information networks; computational resources; models of solar terrestrial processes; data bases and archives; and research students.

1989-01-01

330

Terrestrial Planet Formation Around Close Binary Stars  

NASA Technical Reports Server (NTRS)

Most stars reside in multiple star systems; however, virtually all models of planetary growth have assumed an isolated single star. Numerical simulations of the collapse of molecular cloud cores to form binary stars suggest that disks will form within such systems. Observations indirectly suggest disk material around one or both components within young binary star systems. If planets form at the right places within such circumstellar disks, they can remain in stable orbits within the binary star systems for eons. We are simulating the late stages of growth of terrestrial planets around close binary stars, using a new, ultrafast, symplectic integrator that we have developed for this purpose. The sum of the masses of the two stars is one solar mass, and the initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and in the Alpha Centauri wide binary star system. Giant planets &are included in the simulations, as they are in most simulations of the late stages of terrestrial planet accumulation in our Solar System. When the stars travel on a circular orbit with semimajor axis of up to 0.1 AU about their mutual center of mass, the planetary embryos grow into a system of terrestrial planets that is statistically identical to those formed about single stars, but a larger semimajor axis and/or a significantly eccentric binary orbit can lead to significantly more dynamically hot terrestrial planet systems.

Lissauer, Jack J.; Quintana, Elisa V.

2003-01-01

331

Evaluation of terrestrial primary production using biosphere models and space-based measurements of fluorescence  

NASA Astrophysics Data System (ADS)

Changes in the processes that control terrestrial carbon uptake are highly uncertain but likely to have a significant influence on future atmospheric CO2 levels. RECCAP aims to improve process understanding by reconciling fluxes from top-down CO2 inversions and bottom-up estimates from an ensemble of dynamical global vegetation models (DGVMs). As these models are typically used in projections of climate change a key part of this effort is evaluating drivers of net carbon exchange within the current climate. Of particular importance are the spatial distribution and time rate of change of gross primary productivity (GPP). Recent advances in the remote sensing of solar-induced chlorophyll fluorescence opens up a new possibility to directly measure planetary photosynthesis on spatially resolved scales. Here, we discuss a new methodology for estimating GPP from an optimal combination of an ensemble of DGVMs from the TRENDY project with satellite-based observations of chlorophyll fluorescence from GOSAT. We evaluate optimized fluxes against flux tower and semi-empirical data in N. America, Europe, and S. America, then examine the period 2009-2010 to identify critical regions (i.e., regions with high annual GPP) where optimized and model fluxes diverge.

Parazoo, N.; Bowman, K. W.; Frankenberg, C.; Sitch, S.; Fisher, J. B.; Jones, D. B.; Friedlingstein, P.; Poulter, B.

2013-12-01

332

A review of global terrestrial evapotranspiration: Observation, modeling, climatology, and climatic variability  

NASA Astrophysics Data System (ADS)

This review surveys the basic theories, observational methods, satellite algorithms, and land surface models for terrestrial evapotranspiration, E (or ?E, i.e., latent heat flux), including a long-term variability and trends perspective. The basic theories used to estimate E are the Monin-Obukhov similarity theory (MOST), the Bowen ratio method, and the Penman-Monteith equation. The latter two theoretical expressions combine MOST with surface energy balance. Estimates of E can differ substantially between these three approaches because of their use of different input data. Surface and satellite-based measurement systems can provide accurate estimates of diurnal, daily, and annual variability of E. But their estimation of longer time variability is largely not established. A reasonable estimate of E as a global mean can be obtained from a surface water budget method, but its regional distribution is still rather uncertain. Current land surface models provide widely different ratios of the transpiration by vegetation to total E. This source of uncertainty therefore limits the capability of models to provide the sensitivities of E to precipitation deficits and land cover change.

Wang, Kaicun; Dickinson, Robert E.

2012-06-01

333

Realization of the BIH terrestrial system  

NASA Astrophysics Data System (ADS)

From 1968 through 1983, the BIH has maintained the orientation of the axes of a conventional terrestrial system on the basis of the stability of time series of the earth rotation parameters (ERP) that are implicitly referred to it. The principles of the definition and maintenance of this system are recalled, and its precision and long term stability are evaluated. It is now possible to realize the terrestrial reference system of the BIH, including the origin and orientation of the axes and the scale unit, on the basis of the permanent stations used in the monitoring of the earth's rotation by space geodesy. The transition to the proposed new realization is described. The principles of the future maintenance and dissemination of the BIH terrestrial system are also outlined.

Boucher, C.; Feissel, M.

334

Comparative planetology: Significance for terrestrial geology  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

335

Digital Communication  

NSDL National Science Digital Library

All About Circuits is a website that âÂÂprovides a series of online textbooks covering electricity and electronics.â Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Digital Communication, is the fourteenth chapter in Volume IV âÂÂDigital. A few of the topics covered in this chapter include: Electrical signal types, Optical data communication, and Network topology. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

2008-07-11

336

Triad communications  

NASA Astrophysics Data System (ADS)

Developments in geostationary orbit are discussed and the uses and users of such systems are considered. It is pointed out that by the end of the century the pressure on the geostationary orbit slots will force new approaches in the design and deployment of communications platforms. A triad constellation consisting of a simple constellation of three satellites in a high-inclination 12 h orbit and an apogee approximately at noon over the triad sectors is proposed as an alternate private, supplementary business communications system tailored to the needs of the world's triad of market economies. Orbital parameters include two orbits per day, an eccentricity of 0.741, an argument of perigee of 270, and an inclination orbit of 63.4, similar to those used by Soviet Molniya satellites.

Stephenson, David G.

337

Magnetic fields of the terrestrial planets  

NASA Technical Reports Server (NTRS)

The four terrestrial planets, together with the Earth's Moon, provide a significant range of conditions under which dynamo action could occur. All five bodies have been visited by spacecraft, and from three of the five bodies (Earth, Moon and Mars) we have samples of planetary material upon which paleomagnetic studies have been undertaken. At the present time, only the Earth and Mercury appear to have a significant dipole magnetic field. However, the Moon, and possibly Mars, appear to have had ancient planetary dynamos. Venus does not now have a significant planetary magnetic field, and the high surface temperatures should have prevented the recording of evidence of any ancient magnetic field. Since the solidification of the solid inner core is thought to be the energy source for the terrestrial magnetic field, and since smaller bodies evolve thermally more rapidly than larger bodies, we conjecture that the terrestrial planets are today in three different phases of magnetic activity. Venus is in a predynamo phase, not having cooled to the point of core solidification. Mercury and the Earth are in the middle of their dynamo phase, with Mercury perhaps near the end of its activity. Mars and the Moon seem to be well past their dynamo phase. Much needs to be done in the study of the magnetism of the terrestrial planets. We need to characterize the multipole harmonic structure of the Mercury magnetic field plus its secular variation, and we need to analyze returned samples to attempt to unfold the long-term history of Mercury's dynamo. We need to more thoroughly map the magnetism of the lunar surface and to analyze samples obtained from a wider area of the lunar surface. We need a more complete survey of the present Martian magnetic field and samples from a range of different ages of Martian surface material. Finally, a better characterization of the secular variation of the terrestrial magnetic field is needed in order to unfold the workings of the terrestrial dynamo.

Russell, C. T.

1993-01-01

338

Neural Communication  

NSDL National Science Digital Library

First you will explore the neuron. Then how neurons communicate with each other by exploring action potentials and neural transmission. Let's start with the neuron. Explore the neuron and fill out the worksheet by labeling each part of the neuron and giving a brief description of what it does. Structure of the Neuron (Upon entering the site go through each link at the top of the page from intro to terminal buttons) Now take a look ...

Johnson, Mrs.

2010-06-22

339

Magnetic reconnection in the terrestrial magnetosphere  

SciTech Connect

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.

Feldman, W.C.

1984-01-01

340

Solar-Terrestrial Science Strategy Workshop  

NASA Technical Reports Server (NTRS)

The conclusions and recommendations reached at the Solar Terrestrial Science Strategy Workshop are summarized. The charter given to this diverse group was: (1) to establish the level of scientific understanding to be accomplished with the completion of the current and near term worldwide programs; (2) identify the significant scientific questions to be answered by future solar terrestrial programs, and the programs required to answer these questions; and (3) map out a program strategy, taking into consideration currently perceived space capabilities and constraints, to accomplish the identified program.

Banks, Peter M. (editor); Roberts, William T. (editor); Kropp, Jack (editor)

1989-01-01

341

Problems of solar-terrestrial relationships  

NASA Astrophysics Data System (ADS)

Topics considered include studies on solar-terrestrial physics at the Academy of Sciences of the Turkmen SSR, the physical nature of solar flares, the energetics of solar-terrestrial relationships, and the energetics of the interplanetary medium at the earth's orbit. Attention is also given to the interaction of cosmic rays with the magnetosphere and ionosphere, the transport of solar wind energy to the earth's magnetosphere, and the precipitation of high-energy electrons from the inner magnetosphere to the lower ionosphere at subauroral latitudes.

Pushkov, N. V.; Ovezgeldyev, O. G.; Khanberdyev, A.; Miroshnichenko, M. I.

342

Tectonic Evolution of the Terrestrial Planets  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

343

Wireless Communications  

NSDL National Science Digital Library

Wireless communications is an industry that is growing at an incredible rate. Cellular phones are the most obvious example of this trend; it is hard to go anywhere without seeing someone using one. Rapidly advancing technologies and lower prices are making this all possible. At the current pace, there seems to be no limit to what is possible in the wireless industry.To learn about the events that led up to present day wireless communications, this site offers a very informative history of telecommunications (1) that goes all the way back to the time of carrier pigeons. A good introduction to wireless networking can be found in this mini-tutorial (2). The best parts of this tutorial are the discussions of many recent wireless developments and technologies. There are a few interactive games and activities that are supposed to be instructive and entertaining, but some of them can be annoying. For the more technically savvy user, the third site (3) starts by describing many of the principles that drive current wireless systems. The second part examines the technologies that will be used in future generations of services. To build on this material, the third generation mobile communications systems (3G) is the central topic at 3G Newsroom (4), providing breaking news about the development of 3G technology. Additionally, the site has an excellent introduction to 3G, including its applications and specifications. One of the advancements that is paving the way toward 3G is Bluetooth, which is explained in great detail here (5). This technology is capable of very high data transfer rates, but there are some limitations, which are all discussed in the articles on the site. Although Bluetooth is raising plenty of interest, this recent news story (6) is creating more than its share of debate. It outlines a very controversial move by the FCC to allow the use of ultrawideband technology in commercial wireless applications. The author explains in simple terms why there are so many concerns about something that could revolutionize wireless systems. The evolution of the global system for mobile communications (GSM) is traced at GSM World (7). Here users can learn about the roots of the wireless industry as well as what is in store for the future. A special section addresses health concerns associated with mobile phone use. Radio was one of the earliest form of wireless communication, and the Invention of Radio (8) documents the people and events that made it what it is today. The stories of such famous scientists and inventors as Marconi, DeForest, and Armstrong are told in brief accounts, and there is even a link to the well known War of the Worlds radio broadcast.

Leske, Cavin.

2002-01-01

344

The Nature of Communication  

ERIC Educational Resources Information Center

Examines types of communication processes, means of communication, barriers to effective communication, skills to improve the accuracy of communication, and implications for the administrator. (Available from Buckeye Association of School Administrators, 750 Brooksedge Blvd., Westerville, Ohio 43081) (Author)

Spillman, Russell J.

1975-01-01

345

EHF (28/19 GHz) personal communications satellite terminal development  

NASA Technical Reports Server (NTRS)

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.

Pike, Corey

1991-01-01

346

Satellite-aided mobile communications, experiments, applications and prospects  

NASA Technical Reports Server (NTRS)

NASA's ATS-series of satellites were used in a series of communications and position fixing experiments with automotive vehicles, ships and aircraft. Applications of the communications were demonstrated and evaluated for public services including law enforcement, search and rescue, and medical emergency, and for commercial uses in the land and maritime transportation industries. The technical success of the experiments and the demonstrated potential value of the communications prompted a study that concluded an operational satellite-aided system would be a valuable augmentation of planned trunking or cellular type terrestrial mobile radio telephone systems.

Anderson, R. E.; Frey, R. L.; Lewis, J. R.; Milton, R. T.

1980-01-01

347

Snow surface albedo estimation using terrestrial photography  

Microsoft Academic Search

A flexible and inexpensive remote sensing tool for albedo estimation using conventional terrestrial photography and its validation on an Alpine glacier are described. The proposed technique involves georeferencing oblique photographs to a digital elevation model (DEM), defining a mapping function between the information contained on a given pixel of the image and the corresponding cell of the DEM. This is

J. G. Corripio

2004-01-01

348

Validation of a terrestrial food chain model  

Microsoft Academic Search

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

C. C. Travis; B. P. Blaylock

1992-01-01

349

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...

350

SETI [Search for ExtraTerrestrial Intelligence  

Microsoft Academic Search

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

B. M. Oliver

1994-01-01

351

Impact erosion of terrestrial planetary atmospheres  

NASA Technical Reports Server (NTRS)

I review current ideas about the nature of the planetesimals - composition, size distribution, and the planetary encounter velocity. Previous papers on accretion and erosion of planetary atmospheres as a result of multiple impacts are reviewed. Finally, the effects of blowing off a substantial fraction of the atmosphere from a terrestrial planet due to a single giant body impact are discussed.

Ahrens, Thomas J.

1992-01-01

352

Terrestrial Planets: Volatiles Loss & Speed of Rotation  

Microsoft Academic Search

There is a close relation between orbiting frequencies of terrestrial planets and intensities of their outgassing [1]. ``Sweeping'' out volatiles of their bodies is provoked and facilitated by body shaking (wave oscillations) caused by movement of celestial bodies in elliptical orbits. Non-round orbits cause inertia-gravity warpings in all spheres of the bodies producing their tectonic granulation. The higher orbiting frequency

G. G. Kochemasov

2004-01-01

353

High efficiency, long life terrestrial solar panel  

NASA Technical Reports Server (NTRS)

The design of a high efficiency, long life terrestrial module was completed. It utilized 256 rectangular, high efficiency solar cells to achieve high packing density and electrical output. Tooling for the fabrication of solar cells was in house and evaluation of the cell performance was begun. Based on the power output analysis, the goal of a 13% efficiency module was achievable.

Chao, T.; Khemthong, S.; Ling, R.; Olah, S.

1977-01-01

354

Orbiting mirrors for terrestrial energy supply  

NASA Technical Reports Server (NTRS)

A system of orbiting reflectors termed 'SOLARES' is proposed as a means of reducing the diurnal variation and increasing the average intensity of sunlight for terrestrial solar power systems. The paper discusses orbital considerations for the placement of the reflectors, insolation profiles, ground conversion options, costs, and environmental and social effects.

Billman, K. W.; Gilbreath, W. P.; Bowen, S. W.

1978-01-01

355

Magnetic fields of the terrestrial planets  

Microsoft Academic Search

The four terrestrial planets, together with the Earth's Moon, provide a significant range of conditions under which dynamo action could occur. All five bodies have been visited by spacecraft, and from three of the five bodies (Earth, Moon and Mars) we have samples of planetary material upon which paleomagnetic studies have been undertaken. At the present time, only the Earth

C. T. Russell

1993-01-01

356

Monogenetic volcanoes of the terrestrial planets  

Microsoft Academic Search

Monogenetic volcanic activity has produced cinder cones and small shield volcanoes on the earth, moon, and Mars. Extraterrestrial cinder cones have median volumes only 25% as large as average terrestrial cinder cones, implying that their magma chambers are smaller and shallower (1 km depth vs 3 km). Ejection velocities for lunar and Martian cinder cones range from 20 to 70

C. A. Wood

1979-01-01

357

Alkaloids and other constituents from Tribulus terrestris  

Microsoft Academic Search

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.

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

1999-01-01

358

Saponins in Tribulus terrestris – Chemistry and Bioactivity  

Microsoft Academic Search

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

I. Kostova; D. Dinchev

2005-01-01

359

Steroid saponins II. Glycosides of Tribulus terrestris  

Microsoft Academic Search

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.

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

1972-01-01

360

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...

361

Object Extraction from Terrestrial Laser Scanning Data  

Microsoft Academic Search

SUMMARY Terrestrial laser scanning emerges as a leading technology for direct 3D documentation of natural scenes irrespective of their complexity. The detailed level of description comes however at the cost of huge volume of data in form of unorganized, unevenly spaced, three- dimensional points. The cloud of points provides a geometric description of the scanned scene but carries no semantic

Sagi FILIN

2009-01-01

362

Communication apprehension and health communication and behaviors  

Microsoft Academic Search

Two samples of working and college adults reported on their communication apprehension and health behaviors and communication. Specific communication apprehension as measured by a modified version of the Form State scale showed moderate to large negative effects on health communication (talking with physician, seeking health information) and almost no effects on health behaviors (tobacco use, exercise, health fairs) except diet.

Rebecca Chory; William Beynon

1997-01-01

363

Disaster warning system: Satellite feasibility and comparison with terrestrial systems. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

The Disaster Warning System (DWS) is a conceptual system which will provide the National Weather Service (NWS) with communication services in the 1980s to help minimize losses caused by natural disasters. The object of this study is a comparative analysis between a terrestrial DWS and a satellite DWS. Baseline systems satisfying the NOAA requirements were synthesized in sufficient detail so that a comparison could be made in terms of performance and cost. The cost of both baseline systems is dominated by the disaster warning and spotter reporting functions. An effort was undertaken to reduce system cost through lower-capacity alternative systems generated by modifying the baseline systems. By reducing the number of required channels and modifying the spotter reporting techniques, alternative satellite systems were synthesized. A terrestrial alternative with the coverage reduced to an estimated 95 percent of the population was considered.

Spoor, J. H.; Hodge, W. H.; Fluk, M. J.; Bamford, T. F.

1974-01-01

364

Terrestrial Planet Formation in Binary Star Systems  

NASA Technical Reports Server (NTRS)

Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

2006-01-01

365

Potential markets for advanced satellite communications  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

366

ANIMAL COMMUNICATION.  

PubMed

Semiotics and ethology have converged in a new behavioral science, zoosemiotics. Those who are interested in the theoretical analysis of the complex problems of non-verbal behavior that arise where these two disciplines interact aim to treat comprehensively animal communication systems by the aid of representations that have proved illuminating in the study of sentences of human language. Students of zoosemiotics are concerned with codes and messages much as linguists are concerned with competence, or language, and performance, or speech. They thus face the twin tasks of constructing a model for the addresser to specify how a message is encoded and transformed into a signal carried by a variety of channels to the addressee; and of constructing a model for the addressee to specify the ways in which animals utilize their knowledge of their code to recognize the messages they receive. Finally, they assess the context of the communicative event in the hope of dissecting that which is relevant to the selection process from the rest of the background, a program for which there is as yet neither a procedural eliciting technique nor a satisfactory theoretical solution in sight. PMID:14245775

SEBEOK, T A

1965-02-26

367

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)

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.

Hossain, F.

2013-12-01

368

Space and Terrestrial Photovoltaics: Synergy and Diversity  

NASA Technical Reports Server (NTRS)

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.

Bailey, Sheila; Raffaelle, Ryne; Emery, Keith

2002-01-01

369

Linkages between terrestrial ecosystems and the atmosphere  

NASA Technical Reports Server (NTRS)

The primary research issue in understanding the role of terrestrial ecosystems in global change is analyzing the coupling between processes with vastly differing rates of change, from photosynthesis to community change. Representing this coupling in models is the central challenge to modeling the terrestrial biosphere as part of the earth system. Terrestrial ecosystems participate in climate and in the biogeochemical cycles on several temporal scales. Some of the carbon fixed by photosynthesis is incorporated into plant tissue and is delayed from returning to the atmosphere until it is oxidized by decomposition or fire. This slower (i.e., days to months) carbon loop through the terrestrial component of the carbon cycle, which is matched by cycles of nutrients required by plants and decomposers, affects the increasing trend in atmospheric CO2 concentration and imposes a seasonal cycle on that trend. Moreover, this cycle includes key controls over biogenic trace gas production. The structure of terrestrial ecosystems, which responds on even longer time scales (annual to century), is the integrated response to the biogeochemical and environmental constraints that develop over the intermediate time scale. The loop is closed back to the climate system since it is the structure of ecosystems, including species composition, that sets the terrestrial boundary condition in the climate system through modification of surface roughness, albedo, and, to a great extent, latent heat exchange. These separate temporal scales contain explicit feedback loops which may modify ecosystem dynamics and linkages between ecosystems and the atmosphere. The long-term change in climate, resulting from increased atmospheric concentrations of greenhouse gases (e.g., CO2, CH4, and nitrous oxide (N2O)) will further modify the global environment and potentially induce further ecosystem change. Modeling these interactions requires coupling successional models to biogeochemical models to physiological models that describe the exchange of water, energy, and biogenic trace gases between the vegetation and the atmosphere at fine time scales. There does not appear to be any obvious way to allow direct reciprocal coupling of atmospheric general circulation models (GCM's), which inherently run with fine time steps, to ecosystem or successional models, which have coarse temporal resolution, without the interposition of physiological canopy models. This is equally true for biogeochemical models of the exchange of carbon dioxide and trace gases. This coupling across time scales is nontrivial and sets the focus for the modeling strategy.

Bretherton, Francis; Dickinson, Robert E.; Fung, Inez; Moore, Berrien, III; Prather, Michael; Running, Steven W.; Tiessen, Holm

1992-01-01

370

Space and Terrestrial Photovoltaics: Synergy and Diversity  

NASA Astrophysics Data System (ADS)

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.

Bailey, Sheila; Raffaelle, Ryne; Emery, Keith

2002-10-01

371

Need for, and financial feasibility of, satellite-aided land mobile communications  

NASA Technical Reports Server (NTRS)

Questions regarding the role of a mobile-satellite system in augmenting the terrestrial communications system are considered, and a market assessment study is discussed. Aspects of an investment analysis are examined, taking into account a three phase financial study of four postulated land Mobile Satellite Service (LMSS) systems, project profitability evaluation methods, risk analysis methods, financial projections, potential investor acceptance standards, and a risk analysis. It is concluded that a satellite augmented terrestrial mobile service appears to be economically and technically superior to a service depending exclusively on terrestrial systems. The interest in the Mobile Satellite Service is found to be worldwide, and the ground equipment market is potentially large.

Castruccio, P. A.; Marantz, C. S.; Freibaum, J.

1982-01-01

372

Individualized Communications  

NASA Technical Reports Server (NTRS)

IntelliWeb and IntelliPrint, products from MicroMass Communications, utilize C Language Integrated Production System (CLIPS), a development and delivery expert systems tool developed at Johnson Space Center. IntelliWeb delivers personalized messages by dynamically creating single web pages or entire web sites based on information provided by each website visitor. IntelliPrint is a product designed to create tailored, individualized messages via printed media. The software uses proprietary technology to generate printed messages that are personally relevant and tailored to meet each individual's needs. Intelliprint is in use in many operations including Brystol-Myers Squibb's personalized newsletter, "Living at Your Best," geared to each recipient based on a health and lifestyle survey taken earlier; and SmithKline Beecham's "Nicorette Committed Quitters Program," in which customized motivational materials support participants in their attempt to quit smoking.

1997-01-01

373

Coherent communications  

NASA Astrophysics Data System (ADS)

Coherent lightwave techniques, when compared to direct detection techniques, offer nearly quantum noise limited sensitivity as well as fine tunability similar to that obtained at radio frequencies. These two aspects provide communication systems planners and engineers a means to better exploit the huge bandwidth of single mode optical fibers. Field trials have been performed showing that such techniques are suitable for transmitting multigigabit per second signals to distances exceeding well over a hundred kilometers. On the other hand, coherent multichannel, frequency division multiple access, local area networks have been proposed and experimented with worldwide. This paper will discuss the theoretical advantages and limitations of the various modulation and detection formats together with the state of the art. Moreover some aspects, related to the introduction of coherent systems in local and metropolitan area networks, will be treated. Finally, some experimental data will be provided and future evolution will be discussed.

Demarchis, G.

1992-05-01

374

Communication spaces  

PubMed Central

Background and objective Annotations to physical workspaces such as signs and notes are ubiquitous. When densely annotated, work areas become communication spaces. This study aims to characterize the types and purpose of such annotations. Methods A qualitative observational study was undertaken in two wards and the radiology department of a 440-bed metropolitan teaching hospital. Images were purposefully sampled; 39 were analyzed after excluding inferior images. Results Annotation functions included signaling identity, location, capability, status, availability, and operation. They encoded data, rules or procedural descriptions. Most aggregated into groups that either created a workflow by referencing each other, supported a common workflow without reference to each other, or were heterogeneous, referring to many workflows. Higher-level assemblies of such groupings were also observed. Discussion Annotations make visible the gap between work done and the capability of a space to support work. Annotations are repairs of an environment, improving fitness for purpose, fixing inadequacy in design, or meeting emergent needs. Annotations thus record the missing information needed to undertake tasks, typically added post-implemented. Measuring annotation levels post-implementation could help assess the fit of technology to task. Physical and digital spaces could meet broader user needs by formally supporting user customization, ‘programming through annotation’. Augmented reality systems could also directly support annotation, addressing existing information gaps, and enhancing work with context sensitive annotation. Conclusions Communication spaces offer a model of how work unfolds. Annotations make visible local adaptation that makes technology fit for purpose post-implementation and suggest an important role for annotatable information systems and digital augmentation of the physical environment.

Coiera, Enrico

2014-01-01

375

Feasibility study on radio communications using high altitude radio platform in the stratosphere - Applicability to mobile radio and coverage performance  

Microsoft Academic Search

It is possible that a platform, powered by microwaves beamed from the earth, carrying radio equipment and flying in the stratosphere, could be used for radio relay such as satellite communications, terrestrial microwave radio relay, land mobile base stations. In the Communication Research Laboratory, feasibility studies were started in 1989 on application of the high altitude radio platform (HARP) to

Taiji Saruwatari

1991-01-01

376

The debris disk - terrestrial planet connection  

NASA Astrophysics Data System (ADS)

The eccentric orbits of the known extrasolar giant planets provide evidence that most planet-forming environments undergo violent dynamical instabilities. Here, we numerically simulate the impact of giant planet instabilities on planetary systems as a whole. We find that populations of inner rocky and outer icy bodies are both shaped by the giant planet dynamics and are naturally correlated. Strong instabilities - those with very eccentric surviving giant planets - completely clear out their inner and outer regions. In contrast, systems with stable or low-mass giant planets form terrestrial planets in their inner regions and outer icy bodies produce dust that is observable as debris disks at mid-infrared wavelengths. Fifteen to twenty percent of old stars are observed to have bright debris disks (at ? ~ 70?m) and we predict that these signpost dynamically calm environments that should contain terrestrial planets.

Raymond, Sean N.; Armitage, Philip J.; Moro-Martín, Amaya; Booth, Mark; Wyatt, Mark C.; Armstrong, John C.; Mandell, Avi M.; Selsis, Franck

2011-11-01

377

The Virtual-Solar Terrestrial Observatory  

NASA Astrophysics Data System (ADS)

In the Virtual Solar Terrestrial Observatory (VSTO) project, we are providing an electronic repository of observational, data, theoretical models, and analysis and interpretation results in the solar-terrestrial physics domain. We are also designing and implementing tools and infrastructure for accessing and using the data. In this presentation, we describe the next version of the prototype leading to a portal release in late summer along with the supporting scientific and technical infrastructure. We present of collection of use-cases, and what we have learned about the processes involved in developing VSTO, the required semantics, how they influence the evolution of the framework architecture, technologies and development and refinement of service interfaces.VSTO is an NSF/SCI-funded, joint effort between the High Altitude Observatory and the Scientific Computing Division at the National Center for Atmospheric Research (NCAR) and McGuinness Associates Consulting.

Middleton, D.; Fox, P.; McGuinness, D.; Cinquini, L.; Darnell, T.; Benedict, J.; Garcia, J.; West, P.; Solomon, S.

2006-05-01

378

Intermittent plasma fluctuation in the terrestrial foreshock  

NASA Astrophysics Data System (ADS)

In the paper the intermittent plasma fluctuation in the terrestrial foreshock is studied, using the FGM magnetic records of the Cluster mission. It is argued that the intermittent state of the plasma regime can be adequately measured in certain space and time through the fourth statistical moments, i.e. the flatness of the incremental magnetic records. It is emphasized that using the simultaneous multi-spacecraft observations, the intermittency can be revealed not only in temporal, but also in spatial scale. By computing the flatness along the orbit of the Cluster mission we present the spatial variation of the intermittent state of the foreshock plasma in terms of the distance from the terrestrial bow shock (BS) and the angle of incidence of the IMF line to the BS normal. The relation between the level of intermittent plasma state and the varying solar wind parameters (bulk speed, Alfvén Mach number, dynamic pressure) is also studied.

Kovács, P.; Vadász, G.; Heilig, B.

2012-04-01

379

Changes in ecologically critical terrestrial climate conditions.  

PubMed

Terrestrial ecosystems have encountered substantial warming over the past century, with temperatures increasing about twice as rapidly over land as over the oceans. Here, we review the likelihood of continued changes in terrestrial climate, including analyses of the Coupled Model Intercomparison Project global climate model ensemble. Inertia toward continued emissions creates potential 21st-century global warming that is comparable in magnitude to that of the largest global changes in the past 65 million years but is orders of magnitude more rapid. The rate of warming implies a velocity of climate change and required range shifts of up to several kilometers per year, raising the prospect of daunting challenges for ecosystems, especially in the context of extensive land use and degradation, changes in frequency and severity of extreme events, and interactions with other stresses. PMID:23908225

Diffenbaugh, Noah S; Field, Christopher B

2013-08-01

380

The search for extra-terrestrial intelligence.  

PubMed

Modern history of the search for extra-terrestrial intelligence is reviewed. The history of radio searches is discussed, as well as the major advances that have occurred in radio searches and prospects for new instruments and search strategies. Recent recognition that searches for optical and infrared signals make sense, and the reasons for this are described, as well as the equipment and special detection methods used in optical searches. The long-range future of the search for extra-terrestrial intelligence (SETI) is discussed in the context of the history of rapid change, on the cosmic and even the human time scale, of the paradigms guiding SETI searches. This suggests that SETI searches be conducted with a very open mind. PMID:21220287

Drake, Frank

2011-02-13

381

Paleo-aridity index for terrestrial deposits  

Microsoft Academic Search

We present a paleo-aridity index for terrestrial deposits based on comparing 18-O in tooth enamel. Oxygen-18 is enriched in the residual fluid during evaporation, for example in lakes or in leaves. We characterize taxa that are sensitive to evaporation (ES) and compare them to others that are not sensitive to evaporation (EI). The 18-O concentration in body water is preserved

T. E. Cerling; N. E. Levin; B. H. Passey; J. M. Harris; J. R. Ehleringer

2005-01-01

382

Pollutant-induced changes in terrestrial communities  

Microsoft Academic Search

This thesis concerns metal-induced changes in terrestrial nematode communities exposed in microcosm-experiments and in a manipulative field experiment. Indigenous nematode communities, present in freshly collected agricultural soil, were exposed to heavy metals applied singly (Cd, Cu, Ni and Zn) or in combination under different test conditions. Depending on abiotic characteristics such as soil pH and biotic characteristics such as the

G. W. Korthals

1997-01-01

383

Nonuniform cratering of the terrestrial planets  

Microsoft Academic Search

Article history: We estimate the impact flux and cratering rate as a function of latitude on the terrestrial planets using a model distribution of planet crossing asteroids and comets (Bottke, W.F., Morbidelli, A., Jedicke, R., Petit, J.-M., Levison, H.F., Michel, P., Metcalfe, T.S., 2002. Icarus 156, 399-433). After determining the planetary impact probabilities as a function of the relative encounter

A. Wieczorek

2008-01-01

384

Lunar and Planetary Science XXXV: Terrestrial Planets  

NASA Technical Reports Server (NTRS)

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.

2004-01-01

385

Long-period solar-terrestrial variability  

SciTech Connect

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.

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

1991-01-01

386

Terrestrial contamination in Apollo lunar samples.  

NASA Technical Reports Server (NTRS)

The contamination prevention procedures adopted for controlling the collection, processing, and analysis of the Apollo lunar samples in order to keep them free of significant levels of terrestrial organic matter are described. The organic contaminants actually found in the samples by the various investigators are summarized. It is shown that the program succeeded in providing investigators with samples containing less than 0.1 ppm total contamination.

Flory, D. A.; Simoneit, B. R.

1972-01-01

387

Terrestrial Laser Scanning Applications in Paleoseismology (Invited)  

Microsoft Academic Search

Essential information about past earthquakes includes their locations, ages, and magnitudes. Documentation requires high accuracy three-dimensional measurements. We present three examples of recent earthquake geology research using terrestrial laser scanning (TLS): 1) the stratigraphic record and age of earthquakes along the south-central San Andreas Fault at Bidart, 2) geomorphic modification of surface rupture from the 1992 M7.3 Landers, California earthquake,

R. Arrowsmith; D. E. Haddad; S. O. Akciz; J. S. Oldow; J. Mauer; D. D. Rhodes

2009-01-01

388

Lunar reflections of terrestrial radio leakage  

NASA Astrophysics Data System (ADS)

Terrestrial radio leakage as reflected off the moon has been observed with the Arecibo antenna. The authors find that military radars and television transmitters are main contributors in the 150 - 500 MHz range, as predicted in the model of Sullivan et al. (1978). The earth indeed is revealing itself (eventually) to any interstellar eavesdropper with an Arecibo-like antenna at distances up to 30 light years, and with a Cyclops-like system up to fifteen times farther.

Sullivan, W. T., III; Knowles, S. H.

389

Experimental Tribulus terrestris poisoning in goats  

Microsoft Academic Search

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,

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

2004-01-01

390

A toy terrestrial carbon flow model  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

391

Sun and Solar-terrestrial Physics  

NASA Astrophysics Data System (ADS)

The Sun is of central importance in astronomy. On the one hand, many basic processes that occur throughout the cosmos may be well observed in the Sun and, on the other hand, the Sun acts as a source of the radiation and plasma emissions that affect the Earth in many ways. The study of the interaction of the Sun and its solar wind with the Earth is the burgeoning field of solar-terrestrial physics...

Priest, E.; Murdin, P.

2000-11-01

392

Deep space optical communication via relay satellite  

NASA Technical Reports Server (NTRS)

The application of optical communications for a deep space link via an earth-orbiting relay satellite is discussed. The system uses optical frequencies for the free-space channel and RF links for atmospheric transmission. The relay satellite is in geostationary orbit and contains the optics necessary for data processing and formatting. It returns the data to earth through the RF terrestrial link and also transmits an optical beacon to the satellite for spacecraft return pointing and for the alignment of the transmitting optics. Future work will turn to modulation and coding, pointing and tracking, and optical-RF interfacing.

Dolinar, S.; Vilnrotter, V.; Gagliardi, R.

1981-01-01

393

Smart Grid Development Issues for Terrestrial and Space Applications  

NASA Technical Reports Server (NTRS)

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.

Soeder, James F.

2011-01-01

394

Hydrolytic microbial communities in terrestrial ecosystems  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

395

Advanced Communications Technology: Mobile Communications Requirements Report.  

National Technical Information Service (NTIS)

The Coast Guard's mobile communications requirements will outstrip existing system capabilities, available capacity, and affordability by the late 1990s. This will require changes in the mix of mobile communications equipment and services used by operatio...

1998-01-01

396

What Is Communicative?  

ERIC Educational Resources Information Center

Examines word "communicative" and nature of communication and suggests it should not be applied to a methodology. Draws distinction between "communicative" and "noncommunicative" activities while claims each has its place in balanced approach to language teaching. (Author/BK)

Harmer, Jeremy

1982-01-01

397

Measuring Communication Apprehension  

ERIC Educational Resources Information Center

Discusses the development of a self-report measure of oral communication within an organizational environment and investigates whether or not oral communication apprehension in employment is related to general communication apprehension. (MH)

Scott, Michael D.; And Others

1978-01-01

398

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

NASA Astrophysics Data System (ADS)

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

Mecikalski, John; Smith, Tracy; Weygandt, Stephen

2014-05-01

399

Workshop on Oxygen in the Terrestrial Planets  

NASA Technical Reports Server (NTRS)

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

2004-01-01

400

Intercomparisons of ground-based and satellite-based lightning measurements used in creating a proxy dataset for the Geostationary Lightning Mapper  

NASA Astrophysics Data System (ADS)

We have been comparing several ground-based lightning RF sensing networks (LMA, WTLN, WWLLN) with the satellite-based, optical sensing Lightning Imaging Sensor (LIS). The desire is to create a realistic proxy dataset for the upcoming Geostationary Lightning Mapper (GLM), also an optical sensor. The LIS data are the closest approximation that we have for GLM data, but since it is a Low-Earth Orbiting (LEO) sensor, any spot on the ground is observed for no more than 80 s. The goal is to be able to use any ground-based sensing network, which are typically operated 24x7, and build a transfer function that will allow us to generate proxy GLM pixels. This process is complicated because ground networks are RF sensors and the LIS is an optical sensor. This means that (1) they are sensing different physics during the flash, and (2) the cloud does not scatter RF, but is a very effective light scatterer. The North Alabama Lightning Mapper Array (NALMA) is a VHF sensing network and in a comparison with LIS over many years but limited space (about 150 km from Huntsville, AL), we find a coincidence rate of 70-80%. The WTLN senses a range of the spectrum from VLF to HF; a comparison with LIS of a few months of data that ranges across the Western Hemisphere, we find a coincidence rate of 50-70%. The WWLLN network senses VLF radiation and a comparison with LIS of one month of data also covering the Western Hemisphere, we find a coincidence rate of 7-15%. We will show how a transfer function is derived and give details about how GLM proxy data are generated.

Bateman, M. G.; Thompson, K. B.; Mach, D. M.; Goodman, S. J.; Heckman, S.; Holzworth, R. H.; Koshak, W. J.; Blakeslee, R.

2011-12-01

401

A comparison of two above-ground biomass estimation techniques integrating satellite-based remotely sensed data and ground data for tropical and semiarid forests in Puerto Rico  

NASA Astrophysics Data System (ADS)

Two above-ground forest biomass estimation techniques were evaluated for the United States Territory of Puerto Rico using predictor variables acquired from satellite based remotely sensed data and ground data from the U.S. Department of Agriculture Forest Inventory Analysis (FIA) program. The U.S. Environmental Protection Agency (EPA) estimated above-ground forest biomass implementing methodology first posited by the Woods Hole Research Center developed for conterminous United States (National Biomass and Carbon Dataset [NBCD2000]). For EPA's effort, spatial predictor layers for above-ground biomass estimation included derived products from the U.S. Geologic Survey (USGS) National Land Cover Dataset 2001 (NLCD) (landcover and canopy density), the USGS Gap Analysis Program (forest type classification), the USGS National Elevation Dataset, and the NASA Shuttle Radar Topography Mission (tree heights). In contrast, the U.S. Forest Service (USFS) biomass product integrated FIA ground-based data with a suite of geospatial predictor variables including: (1) the Moderate Resolution Imaging Spectrometer (MODIS)-derived image composites and percent tree cover; (2) NLCD land cover proportions; (3) topographic variables; (4) monthly and annual climate parameters; and (5) other ancillary variables. Correlations between both data sets were made at variable watershed scales to test level of agreement. Notice: This work is done in support of EPA's Sustainable Healthy Communities Research Program. The U.S EPA funded and conducted the research described in this paper. Although this work was reviewed by the EPA and has been approved for publication, it may not necessarily reflect official Agency policy. Mention of any trade names or commercial products does not constitute endorsement or recommendation for use.

Iiames, J. S.; Riegel, J.; Lunetta, R.

2013-12-01

402

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)

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.

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

403

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)

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.

ÁLvarez, A.; Orfila, A.; Tintoré, J.

2004-03-01

404

Communication Apprehension and Health Communication and Behaviors.  

ERIC Educational Resources Information Center

Finds that specific communication apprehension showed moderate to large negative effects on health communication (talking with physician, seeking health information) and almost no effects on health behaviors (tobacco use, exercise, health fairs) except diet; and that general-trait communication apprehension showed similar, though smaller, effects…

Booth-Butterfield, Steve; Beynon, William; Chory, Rebecca

1997-01-01

405

Communicating Effectively PDF  

Cancer.gov

Effective communication is essential for the delivery of quality cancer palliative care. And yet, healthcare providers often lack the skills to communicate effectively with their patients and families.

406

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

NASA Astrophysics Data System (ADS)

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.

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

407

Rethinking the terrestrial water balance: Steps toward a comprehensive indicator framework  

NASA Astrophysics Data System (ADS)

Freshwater scarcity for humans and ecosystems is one of the most serious global challenges of the 21st century. Caused in part by human disturbance of the hydrologic cycle, patterns of water scarcity also reflect large, underlying variations in terrestrial water availability that precede human influence. In recent years, growing concerns about water scarcity have prompted the development and application of distributed, continental-to-global scale water balance models for water-resource assessment, fostering the important new sub-discipline of global hydrology. However, fundamental concepts of water availability have not kept pace with developments in modeling tools. To facilitate fundamental thinking and communication in this growing field, we introduce a new indicator framework based on a spatially distributed, time-dependent approach to the terrestrial water balance. The framework takes advantage of gridded climate, hydrology, and landscape data, is equally pertinent to dryland and humid regions of the world, and integrates traditional (runoff-based) and emerging perspectives on terrestrial water availability—including the blue/green water paradigm now gaining currency in the global water planning and management community. We derive the indicator framework from a general statement of the landscape water balance equation, and then illustrate the relevance of the framework to the extremely diverse hydroclimates of the conterminous United States.

Weiskel, P. K.; Wolock, D.; Zarriello, P. J.; Vogel, R. M.; Brandt, S. L.

2009-12-01

408

Primate communication in the pure ultrasound  

PubMed Central

Few mammals—cetaceans, domestic cats and select bats and rodents—can send and receive vocal signals contained within the ultrasonic domain, or pure ultrasound (greater than 20 kHz). Here, we use the auditory brainstem response (ABR) method to demonstrate that a species of nocturnal primate, the Philippine tarsier (Tarsius syrichta), has a high-frequency limit of auditory sensitivity of ca 91 kHz. We also recorded a vocalization with a dominant frequency of 70 kHz. Such values are among the highest recorded for any terrestrial mammal, and a relatively extreme example of ultrasonic communication. For Philippine tarsiers, ultrasonic vocalizations might represent a private channel of communication that subverts detection by predators, prey and competitors, enhances energetic efficiency, or improves detection against low-frequency background noise.

Ramsi