These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
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  

Microsoft Academic Search

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

Richard J Hughes; Jane E Nordholt; Kevin P Mc Cabe; Raymond T Newell; Charles G Pterson

2010-01-01

3

Satellite-based terrestrial production efficiency modeling  

PubMed Central

Production efficiency models (PEMs) are based on the theory of light use efficiency (LUE) which states that a relatively constant relationship exists between photosynthetic carbon uptake and radiation receipt at the canopy level. Challenges remain however in the application of the PEM methodology to global net primary productivity (NPP) monitoring. The objectives of this review are as follows: 1) to describe the general functioning of six PEMs (CASA; GLO-PEM; TURC; C-Fix; MOD17; and BEAMS) identified in the literature; 2) to review each model to determine potential improvements to the general PEM methodology; 3) to review the related literature on satellite-based gross primary productivity (GPP) and NPP modeling for additional possibilities for improvement; and 4) based on this review, propose items for coordinated research. This review noted a number of possibilities for improvement to the general PEM architecture - ranging from LUE to meteorological and satellite-based inputs. Current PEMs tend to treat the globe similarly in terms of physiological and meteorological factors, often ignoring unique regional aspects. Each of the existing PEMs has developed unique methods to estimate NPP and the combination of the most successful of these could lead to improvements. It may be beneficial to develop regional PEMs that can be combined under a global framework. The results of this review suggest the creation of a hybrid PEM could bring about a significant enhancement to the PEM methodology and thus terrestrial carbon flux modeling. Key items topping the PEM research agenda identified in this review include the following: LUE should not be assumed constant, but should vary by plant functional type (PFT) or photosynthetic pathway; evidence is mounting that PEMs should consider incorporating diffuse radiation; continue to pursue relationships between satellite-derived variables and LUE, GPP and autotrophic respiration (Ra); there is an urgent need for satellite-based biomass measurements to improve Ra estimation; and satellite-based soil moisture data could improve determination of soil water stress. PMID:19765285

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

2009-01-01

4

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

5

Comparison of satellite-based evapotranspiration models over terrestrial ecosystems in China  

E-print Network

Comparison of satellite-based evapotranspiration models over terrestrial ecosystems in China Yang and Technology, Changsha, Hunan 410004, China h National Institute for Agro-Environmental Sciences, Tsukuba 305, Beijing 100875, China b State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing

Montana, University of

6

Sequential optimization of a terrestrial biosphere model constrained by multiple satellite based products  

NASA Astrophysics Data System (ADS)

Various satellite-based spatial products such as evapotranspiration (ET) and gross primary productivity (GPP) are now produced by integration of ground and satellite observations. Effective use of these multiple satellite-based products in terrestrial biosphere models is an important step toward better understanding of terrestrial carbon and water cycles. However, due to the complexity of terrestrial biosphere models with large number of model parameters, the application of these spatial data sets in terrestrial biosphere models is difficult. In this study, we established an effective but simple framework to refine a terrestrial biosphere model, Biome-BGC, using multiple satellite-based products as constraints. We tested the framework in the monsoon Asia region covered by AsiaFlux observations. The framework is based on the hierarchical analysis (Wang et al. 2009) with model parameter optimization constrained by satellite-based spatial data. The Biome-BGC model is separated into several tiers to minimize the freedom of model parameter selections and maximize the independency from the whole model. For example, the snow sub-model is first optimized using MODIS snow cover product, followed by soil water sub-model optimized by satellite-based ET (estimated by an empirical upscaling method; Support Vector Regression (SVR) method; Yang et al. 2007), photosynthesis model optimized by satellite-based GPP (based on SVR method), and respiration and residual carbon cycle models optimized by biomass data. As a result of initial assessment, we found that most of default sub-models (e.g. snow, water cycle and carbon cycle) showed large deviations from remote sensing observations. However, these biases were removed by applying the proposed framework. For example, gross primary productivities were initially underestimated in boreal and temperate forest and overestimated in tropical forests. However, the parameter optimization scheme successfully reduced these biases. Our analysis shows that terrestrial carbon and water cycle simulations in monsoon Asia were greatly improved, and the use of multiple satellite observations with this framework is an effective way for improving terrestrial biosphere models.

Ichii, K.; Kondo, M.; Wang, W.; Hashimoto, H.; Nemani, R. R.

2012-12-01

7

Potential markets for a satellite-based mobile communications system  

NASA Technical Reports Server (NTRS)

The objective of the study was to define the market needs for improved land mobile communications systems. Within the context of this objective, the following goals were set: (1) characterize the present mobile communications industry; (2) determine the market for an improved system for mobile communications; and (3) define the system requirements as seen from the potential customer's viewpoint. The scope of the study was defined by the following parameters: (1) markets were confined to U.S. and Canada; (2) range of operation generally exceeded 20 miles, but this was not restrictive; (3) the classes of potential users considered included all private sector users, and non-military public sector users; (4) the time span examined was 1975 to 1985; and (5) highly localized users were generally excluded - e.g., taxicabs, and local paging.

Jamieson, W. M.; Peet, C. S.; Bengston, R. J.

1976-01-01

8

Spacetime effects on satellite-based quantum communications  

NASA Astrophysics Data System (ADS)

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

Bruschi, David Edward; Ralph, Timothy C.; Fuentes, Ivette; Jennewein, Thomas; Razavi, Mohsen

2014-08-01

9

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

10

A satellite-based personal communication system for the 21st century  

NASA Technical Reports Server (NTRS)

Interest in personal communications (PCOMM) has been stimulated by recent developments in satellite and terrestrial mobile communications. A personal access satellite system (PASS) concept was developed at the Jet Propulsion Laboratory (JPL) which has many attractive user features, including service diversity and a handheld terminal. Significant technical challenges addressed in formulating the PASS space and ground segments are discussed. PASS system concept and basic design features, high risk enabling technologies, an optimized multiple access scheme, alternative antenna coverage concepts, the use of non-geostationary orbits, user terminal radiation constraints, and user terminal frequency reference are covered.

Sue, Miles K.; Dessouky, Khaled; Levitt, Barry; Rafferty, William

1990-01-01

11

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

12

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

Microsoft Academic Search

Operational monitoring of global terrestrial gross primary production (GPP) and net primary production (NPP) is now underway using imagery from the satellite-borne Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Evaluation of MODIS GPP and NPP products will require site-level studies across a range of biomes, with close attention to numerous scaling issues that must be addressed to link ground measurements to

P. T URNER; THOMAS K. M AEIRSPERGER; S TITH T. G OWER; A. K I R S C H B A U Mz; STEVE W. R UNNING; M AOSHENG; Z HAO; S TEVEN C. W OFSY; J OHN; L. C AMPBELL; H Y O J U N G K W O Nk; TILDEN P. M EYERS; A. K URC; J O H N A. G A M O N zz

2005-01-01

13

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

14

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

15

Recent climate and fire disturbance impacts on boreal and arctic ecosystem productivity estimated using a satellite-based terrestrial carbon flux model  

NASA Astrophysics Data System (ADS)

and changing fire regimes in the northern (?45°N) latitudes have consequences for land-atmosphere carbon feedbacks to climate change. A terrestrial carbon flux model integrating satellite Normalized Difference Vegetation Index and burned area records with global meteorology data was used to quantify daily vegetation gross primary productivity (GPP) and net ecosystem CO2 exchange (NEE) over a pan-boreal/Arctic domain and their sensitivity to climate variability, drought, and fire from 2000 to 2010. Model validation against regional tower carbon flux measurements showed overall good agreement for GPP (47 sites: R = 0.83, root mean square difference (RMSD) = 1.93 g C m-2 d-1) and consistency for NEE (22 sites: R = 0.56, RMSD = 1.46 g C m-2 d-1). The model simulations also tracked post-fire NEE recovery indicated from three boreal tower fire chronosequence networks but with larger model uncertainty during early succession. Annual GPP was significantly (p < 0.005) larger in warmer years than in colder years, except for Eurasian boreal forest, which showed greater drought sensitivity due to characteristic warmer, drier growing seasons relative to other areas. The NEE response to climate variability and fire was mitigated by compensating changes in GPP and respiration, though NEE carbon losses were generally observed in areas with severe drought or burning. Drought and temperature variations also had larger regional impacts on GPP and NEE than fire during the study period, though fire disturbances were heterogeneous, with larger impacts on carbon fluxes for some areas and years. These results are being used to inform development of similar operational carbon products for the NASA Soil Moisture Active Passive (SMAP) mission.

Yi, Yonghong; Kimball, John S.; Jones, Lucas A.; Reichle, Rolf H.; Nemani, Ramakrishna; Margolis, Hank A.

2013-06-01

16

Leo satellite-based telecommunication network concepts  

NASA Technical Reports Server (NTRS)

Design considerations are discussed for Low Earth Orbit (LEO) satellite based telecommunications networks. The satellites are assumed to be connected to each other via intersatellite links. They are connected to the end user either directly or through gateways to other networks. Frequency reuse, circuit switching, packet switching, call handoff, and routing for these systems are discussed by analogy with terrestrial cellular (mobile radio) telecommunication systems.

Aiken, John G.; Swan, Peter A.; Leopold, Ray J.

1991-01-01

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

A Survey of Terrestrial and Free Space Based Optical Communications Systems  

Microsoft Academic Search

A low-level operational overview of terrestrial and free space optical communications systems is pre- sented. Communication topics such as modulation, multiplexing, and detection are discussed in relation to optical links. Negative channel eects such as dispersion and absorption are investigated with respect to their impact on the channel and the associated bit error rates. The challenges posed by atmospheric disturbances

Adam Attarian

19

Issues for the integration of satellite and terrestrial cellular networks for mobile communications  

NASA Technical Reports Server (NTRS)

Satellite and terrestrial cellular systems naturally complement each other for land mobile communications, even though present systems have been developed independently. The main advantages of the integrated system are a faster wide area coverage, a better management of overloading traffic conditions, an extension to geographical areas not covered by the terrestrial network and, in perspective, the provision of only one integrated system for all mobile communications (land, aeronautical, and maritime). To achieve these goals, as far as possible the same protocols of the terrestrial network should be used also for the satellite network. Discussed here are the main issues arising from the requirements of the main integrated system. Some results are illustrated, and possible future improvements due to technical solutions are presented.

Delre, Enrico; Mistretta, Ignazio; Dellipriscoli, Francesco; Settimo, Franco

1991-01-01

20

Voice and data communication experiments on a wideband satellite/terrestrial internetwork system  

NASA Astrophysics Data System (ADS)

A status report is presented on the testbed and experimental results pertaining to an experimental wideband satellite/terrestrial internetwork system used for the development and experimental evaluation of packet voice and data multiplexing and internetting techniques, as well as advanced satellite/terrestrial integration and routing techniques. Separate local systems have been developed, concentrating on packet voice/data multiplexing (DARPA) and on routing and satellite/terrestrial integration for the Defense Switched Network. Specific experiments in recent years have concentrated on multiuser internet packet speech and on interfacing digital circuit-switched facilities with the wideband packet satellite system.

Heggestad, H. M.; Weinstein, C. J.

21

Maritime terrestrial and satellite communications - Their relative role in the overall maritime radio-communication service in the coming decades  

Microsoft Academic Search

The considerations set forth in the present paper indicate that the maritime radio communications service of the future will be arrived at only after extensive international discussion in a number of fora, including IMCO and CCIR. With the arrival of satellite communications, this process of consultation is at a watershed. It is time now for ideas to be discussed. Gradually

S. R. Temple

1978-01-01

22

Background light environment for free-space optical terrestrial communication links  

Microsoft Academic Search

Free-space optical (FSO) links for high-speed communications between buildings must consider detrimental environmental effects including interference from sunlight in the receiver's instantaneous field of view (IFOV). Sunlight can degrade receive sensitivity resulting in link disruptions, even with significant optical filtering. Thus it is important to characterize this environmental effect for designing and testing optical transceivers. Background light levels are highly

David Rollins; Jeff Baars; David P. Bajorins; Carrie S. Cornish; Kenneth W. Fischer; Thomas Wiltsey

2002-01-01

23

Modeling of terrains for simulation of integrated mobile terrestrial and satellite communications systems  

Microsoft Academic Search

In this paper we present methods to generate models of mountainous regions. For these regions statistical methods are unsuitable to predict the service coverage, blocking and termination probabilities for systems involving fast moving satellites. We present methods using modeled terrains to analyze the service coverage in satellite integrated mobile communications systems. Results of service coverage analyses based on these methods

Gunar Schorcht; Ulrich Freund; Horst Salzwedel; Harald Keller

1996-01-01

24

Integrating satellite and terrestrial technologies for emergency communications: the WISECOM project  

Microsoft Academic Search

In this paper, the main concepts of the Wireless Infrastructure over Satellite for Emergency COMmunications project (WISECOM) are presented. These concepts rely upon the idea of a light and rapidly deployable system that can be autonomously used in remote areas where telecommunication networks have broken down to provide access to emergency telecommunication services using a large set of wide-spread telecommunication

Matteo Berioli; Nicolas Courville; Markus Werner

2007-01-01

25

Physics-based modeling of wave propagation for terrestrial and space communications  

Microsoft Academic Search

This dissertation investigates the solutions to two important and challenging problems of radio wave propagation in wireless communication. The first problem pertains to modeling of wave propagation in foliage. The second problem involves a comprehensive study in enhancing the radio uplink between a ground station and a spacecraft using an array of reflector antennas. Solutions are developed using physics-based modeling

Feinian Wang

2006-01-01

26

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

27

A satellite-based radar wind sensor  

NASA Technical Reports Server (NTRS)

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

Xin, Weizhuang

1991-01-01

28

Physics-based modeling of wave propagation for terrestrial and space communications  

NASA Astrophysics Data System (ADS)

This dissertation investigates the solutions to two important and challenging problems of radio wave propagation in wireless communication. The first problem pertains to modeling of wave propagation in foliage. The second problem involves a comprehensive study in enhancing the radio uplink between a ground station and a spacecraft using an array of reflector antennas. Solutions are developed using physics-based modeling which allows for realistic simulations of physical environments and gives insight into wave propagation mechanisms. For the foliage problem, various models are developed for different applications. The foundation of these advanced models is an existing fractal-based coherent scattering model (FCSM). To extend the region of validity of FCSM, an enhanced version is developed by accounting for mutual coupling among leaves within leaf clusters. An outdoor path-loss measurement is conducted at Ka-band; comparison between measured and simulation results demonstrates a great improvement with the enhanced model. The difficulty of direct application of FCSM to estimate foliage path-loss over long distances is also resolved by analyzing a single block of forest and applying the wave propagation behavior to all forest blocks. This statistical wave propagation model (SWAP) is successfully validated. In order to develop a simple-to-use macro-model for foliage path-loss, sensitivity analysis is performed using a large number of SWAP model simulations. Then a physics-based parametric model is selected and its parameters are related to the foliage/system parameters. Examples of this Michigan foliage attenuation model (MIFAM) are presented for both deciduous and coniferous forests. For the ground array problem, an external uplink phase calibration is needed due to the insufficient accuracy of determining the phase centers of an array of antennas. Three schemes are proposed. The first one presents a radar calibration procedure based on phase conjugation, and uses low earth orbit (LEO) satellites as calibration targets. These targets fall within the array near-field region, and a far-field correction scheme is developed so that the array can focus in the far-field at any desired direction. The second scheme is designed for an all-transmitter array. The Moon, which lies in the array far-field, is selected as the calibration target. InSAR (Interferometric Synthetic Aperture Radar) imaging is employed to deal with such a distributed target. The last scheme investigates the possibility of using existing VLBI (Very Long Baseline Interferometry) infrastructures. System modifications may be required since VLBI is based on downlink operation. However, baseline, delay, and phase measurements from VLBI all provide potential information for calibration.

Wang, Feinian

29

Delivery of satellite based broadband services  

NASA Astrophysics Data System (ADS)

Availability of speedy communication links to individuals and organizations is essential to keep pace with the business and social requirements of this modern age. While the PCs have been continuously growing in processing speed and memory capabilities, the availability of broadband communication links still has not been satisfactory in many parts of the world. Recognizing the need to give fillip to the growth of broadband services and improve the broadband penetration, the telecom policies of different counties have placed special emphasis on the same. While emphasis is on the use of fiber optic and copper in local loop, satellite communications systems will play an important role in quickly establishing these services in areas where fiber and other communication systems are not available and are not likely to be available for a long time to come. To make satellite communication systems attractive for the wide spread of these services in a cost effective way special emphasis has to be given on factors affecting the cost of the bandwidth and the equipment. As broadband services are bandwidth demanding, use of bandwidth efficient modulation technique and suitable system architecture are some of the important aspects that need to be examined. Further there is a need to re-look on how information services are provided keeping in view the user requirements and broadcast capability of satellite systems over wide areas. This paper addresses some of the aspects of delivering broadband services via satellite taking Indian requirement as an example.

Chandrasekhar, M. G.; Venugopal, D.

2007-06-01

30

Component analysis of errors in satellite-based precipitation estimates  

Microsoft Academic Search

Satellite-based precipitation estimates have great potential for a wide range of critical applications, but their error characteristics need to be examined and understood. In this study, six (6) high-resolution, satellite-based precipitation data sets are evaluated over the contiguous United States against a gauge-based product. An error decomposition scheme is devised to separate the errors into three independent components, hit bias,

Yudong Tian; Christa D. Peters-Lidard; John B. Eylander; Robert J. Joyce; George J. Huffman; Robert F. Adler; Kuo-lin Hsu; F. Joseph Turk; Matthew Garcia; Jing Zeng

2009-01-01

31

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

32

"Globalstar, Iridium and other Satellite-Based Mobile Phone  

E-print Network

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

33

SATELLITE BASED SHORT-TERM FORECASTING OF SOLAR IRRADANCE  

E-print Network

the calculation of cloud index images from satellite images and the derivation of ground irradiance from the cloud, the first approach focuses on this issue. A statistically #12;original satellite images forecast of HeliosatSATELLITE BASED SHORT-TERM FORECASTING OF SOLAR IRRADANCE - COMPARISON OF METHODS AND ERROR

Heinemann, Detlev

34

RETHINKING SATELLITE BASED SOLAR IRRADIANCE MODELLING R. W. Mueller  

E-print Network

RETHINKING SATELLITE BASED SOLAR IRRADIANCE MODELLING R. W. Mueller , K.F. Dagestad ¡ , R-German Aerospace Center; 5-Ecole des Mines de Paris ABSTRACT Accurate solar irradiance data are not only Heliosat-3 a new type of solar irradiance scheme is developed. This new type will be based on radiative

Heinemann, Detlev

35

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

36

Automatic GPS satellite based subsidence measurements for Ekofisk  

SciTech Connect

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

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

1995-12-01

37

Operational Satellite-based Surface Oil Analyses (Invited)  

Microsoft Academic Search

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

D. Streett; C. Warren

2010-01-01

38

Evaluation of Satellite-based Rainfall Estimates Using CEOP Data  

Microsoft Academic Search

Recent progress in satellite-based measurement has provided significant advances in the global precipitation observation and application from large scale (e.g. monthly 2.5ox2.5o) to finer scales of daily to hour of 0.25ox0.25o lat-lon or higher. Although global precipitation measurement is becoming available through remote sensing techniques, the quality of the data, however, requires further investigation. With a wide base of global

K. Hsu; S. Sorooshian; D. Braithwaite

2006-01-01

39

Communication.  

ERIC Educational Resources Information Center

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

Strauss, Andre

40

2013 ISES Solar World Congress Review of satellite-based surface solar irradiation databases for  

E-print Network

2013 ISES Solar World Congress Review of satellite-based surface solar irradiation databases explores the possibilities provided by satellite-based surface solar irradiation databases synthesis of 17 satellite-based surface solar irradiation databases available so far is presented through

Paris-Sud XI, Université de

41

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

42

Terrestrial sequestration  

SciTech Connect

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

2008-03-10

43

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

NASA Astrophysics Data System (ADS)

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

Moody, Daniela I.; Smith, David A.

2014-05-01

44

Reassessment of satellite-based estimate of aerosol climate forcing  

NASA Astrophysics Data System (ADS)

uncertainties exist in estimations of aerosol direct radiative forcing and indirect radiative forcing, and the values derived from global modeling differ substantially with satellite-based calculations. Following the approach of Quaas et al. (2008; hereafter named Quaas2008), we reassess satellite-based clear- and cloudy-sky radiative forcings and their seasonal variations by employing updated satellite products from 2004 to 2011 in combination with the anthropogenic aerosol optical depth (AOD) fraction obtained from model simulations using the Goddard Earth Observing System-Chemistry-Advanced Particle Microphysics (GEOS-Chem-APM). Our derived annual mean aerosol clear-sky forcing (-0.59 W m-2) is lower, while the cloudy-sky forcing (-0.34 W m-2) is higher than the corresponding results (-0.9 W m-2 and -0.2 W m-2, respectively) reported in Quaas2008. Our study indicates that the derived forcings are sensitive to the anthropogenic AOD fraction and its spatial distribution but insensitive to the temporal resolution used to obtain the regression coefficients, i.e., monthly or seasonal based. The forcing efficiency (i.e., the magnitude per anthropogenic AOD) for the clear-sky forcing based on this study is 19.9 W m-2, which is about 5% smaller than Quaas2008's value of 21.1 W m-2. In contrast, the efficiency for the cloudy-sky forcing of this study (11 W m-2) is more than a factor of 2 larger than Quaas2008's value of 4.7 W m-2. Uncertainties tests indicate that anthropogenic fraction of AOD strongly affects the computed forcings while using aerosol index instead of AOD from satellite data as aerosol proxy does not appear to cause any significant differences in regression slopes and derived forcings.

Ma, Xiaoyan; Yu, Fangqun; Quaas, Johannes

2014-09-01

45

Validation of the Global NASA Satellite-based Flood Detection System in Bangladesh  

NASA Astrophysics Data System (ADS)

Floods are one of the most destructive natural forces on earth, affecting millions of people annually. Nations lying in the downstream end of an international river basin often suffer the most damage during flooding and could benefit from the real-time communication of rainfall and stream flow data from countries upstream. This is less likely to happen among developing nations due to a lack of freshwater treaties (Balthrop and Hossain, Water Policy, 2009). A more viable option is for flood-prone developing nations to utilize the global satellite rainfall and modeled runoff data that is independently and freely available from the NASA Satellite-based Global Flood Detection System. Although the NASA Global Flood Detection System has been in operation in real-time since 2006, the ‘detection’ capability of flooding has only been validated against qualitative reports in news papers and other types of media. In this study, a more quantitative validation against in-situ measurements of the flood detection system over Bangladesh is presented. Using ground-measured stream flow data as well as satellite-based flood potential and rainfall data, the study looks into the relationship between rainfall and flood potential, rainfall and stream flow, and stream flow and flood potential for three very distinct river systems in Bangladesh - 1) Ganges- a snow-fed river regulated by upstream India 2) Brahmaputra - a snow-fed river that is also braided 3) Meghna - a rain-fed river. The quantitative assessment will show the effectiveness of the NASA Global Flood Detection System for a very humid and flood prone region like Bangladesh that is also faced with tremendous transboundary hurdles that can only be resolved from the vantage of space.

Moffitt, C. B.

2009-12-01

46

Satellite -Based Networks for U-Health & U-Learning  

NASA Astrophysics Data System (ADS)

The use of modern Information and Communication Technologies (ICT) as enabling tools for healthcare services (eHealth) introduces new ways of creating ubiquitous access to high-level medical care for all, anytime and anywhere (uHealth). Satellite communication constitutes one of the most flexible methods of broadband communication offering high reliability and cost-effectiveness of connections meeting telemedicine communication requirements. Global networks and the use of computers for educational purposes stimulate and support the development of virtual universities for e-learning. Especially real-time interactive applications can play an important role in tailored and personalised services.

Graschew, G.; Roelofs, T. A.; Rakowsky, S.; Schlag, P. M.

2008-08-01

47

Virtual private network issues using satellite based networks  

Microsoft Academic Search

A number of commercial wideband satellite systems have been proposed to offer Internet access services and some satellite systems have already begun offering such services (see http:\\/\\/www.time.com\\/time\\/digital\\/reports\\/broadband\\/wireless.html, 2000). A unique characteristic of these satellite systems, as compared to terrestrial Internet access systems, is their use of performance enhancing proxies (PEPs) to improve the performance of Internet protocols over the satellite

E. Olechna; P. Feighery; S. Hryckiewicz

2001-01-01

48

Communications  

NASA Technical Reports Server (NTRS)

Communication in its many forms is a critical component for an effective Space Grant Program. Good communication is needed within individual Space Grant College/Consortia, for example between consortium affiliates and the consortium program office. Effective communication between the several programs, NASA Headquarters, and NASA field centers also is required. Further, communication among the above program elements, industry, local and state government, and the public also are necessary for meeting program objectives.

Stouffer, Donald D.

1990-01-01

49

Communications.  

ERIC Educational Resources Information Center

This manual, prepared by a distributive education (DE) class at Delaware State College, was designed for use by DE teacher-coordinators who teach communication skills. Included are lessons, activities, and resource materials relating to the following communication skills: functional speaking, written communication, telephone etiquette, customer…

Grandfield, Raymond J., Ed.

50

The use of satellite-based technology in developing countries  

E-print Network

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

Wood, Danielle Renee

2007-01-01

51

2013 ISES Solar World Congress Review of satellite-based surface solar irradiation databases for  

E-print Network

2013 ISES Solar World Congress Review of satellite-based surface solar irradiation databases explores the possibilities provided by satellite-based surface solar irradiation databases. Selection and/or peer-review under responsibility of ISES Keywords: surface solar irradiation; satellite

Recanati, Catherine

52

Satellite-based monitoring of air quality within QUITSAT project  

NASA Astrophysics Data System (ADS)

Satellite remote sensing of both trace gas constituents and Particulate Matter (PM) can be profitably exploited in Air Quality (AQ) assessment. The actual potential role of satellite observations is here highlighted combined with regional meteorological and Chemical Transport Models (CTM) in the context of air quality monitoring as experienced in QUITSAT Project over Northern Italy (from 43:09 to 46:39 N, from 6:19 to 14:23 E). QUITSAT (2006-2009) is a pilot project funded by the Italian Space Agency (ASI) in the framework of its institutional priorities for the Natural and Technological disaster management programme. AQ monitoring is in general based on local ground measurements. In recent years, this issue has been inserted in a more extended frame, in which CTM have joined ground-based data and satellite observations to provide a better characterization of AQ monitoring, forecasting and planning on a regional scale. In particular, two satellite-based products arisen from analysis methodologies developed in QUITSAT and relative to significant pollutants as PM2.5 and NO2 are presented within this work. The MODIS sensors capability (Terra and Aqua/NASA platforms) to retrieve Aerosol Optical Properties (AOP) has been used in a semi-empirical approach to estimate PM2.5 content at the ground. At first, PM2.5 concentration sampled in several sites over Northern Italy are employed in order to infer AOP to PM conversion parameters. A spatial-temporal coincidence procedure has been performed amongst EO and non-EO data. To take into account the aerosol columnar dispersion and the AOP dependence on the relative humidity (RH) meteorological fields (Planetary Boundary Layer and RH) simulated by MM5 are considered. MODIS aerosol level 2 products (MOD04 and MYD04 collection 5, 10x10 km2 spatial resolution) and PM2.5 samplings performed by Regional Environmental Agencies (ARPA Emilia Romagna and ARPA Lombardia) and carried out over further 6 measurements sites (located in Milano, Bologna, S. Pietro Capofiume, Oasi Bine, Monte Cimone e Bormio) relative to 2004, summer 2007 and winter 2008, are employed to derive the best regression parameters for AOD to PM2.5 conversion relationship. The conversion parameters have been grouped on a monthly basis and spatially interpolated over the whole domain. Thus, daily maps of satellite-based PM2.5 concentrations over Northern Italy are derived. Monthly averaged values have been compared to in-situ PM2.5 sampling providing a good agreement. OMI (Aura/NASA platform) NO2 tropospheric column (spatial resolution 13x24 km2) are merged with the simulations of the Transport Chemical Aerosol Model (TCAM) performed at resolution of 5x5 km2. The method used is a weighted rescaling of the model column in the troposphere according to the OMI observations, where the weights are the measurement errors and the model column variances within the satellite ground-pixel, respectively. Nitrogen dioxide above the TCAM maximum modelled altitude (that is about 4 km) are considered as negligible in our approach. Actually this is a good approximation when medium and high polluted regions are observed (as Northern Italy) while further analysis could be required over low polluted regions to exclude any significant NO2 amount in the middle and upper troposphere. The obtained ground concentrations of NO2 have been compared with in-situ observations performed by the Regional Environmental Agencies (ARPA Emilia Romagna and ARPA Lombardia) showing good agreement either over rural area or over urban region where horizontal gradient in NO2 concentration could be relevant. The work is part of the pilot project QUITSAT, funded by the Italian Space Agency (ASI), contract I/035/06/0, http://www.quitsat.it.

di Nicolantonio, W.

2009-04-01

53

Satellite-based estimates of groundwater depletion in India.  

PubMed

Groundwater is a primary source of fresh water in many parts of the world. Some regions are becoming overly dependent on it, consuming groundwater faster than it is naturally replenished and causing water tables to decline unremittingly. Indirect evidence suggests that this is the case in northwest India, but there has been no regional assessment of the rate of groundwater depletion. Here we use terrestrial water storage-change observations from the NASA Gravity Recovery and Climate Experiment satellites and simulated soil-water variations from a data-integrating hydrological modelling system to show that groundwater is being depleted at a mean rate of 4.0 +/- 1.0 cm yr(-1) equivalent height of water (17.7 +/- 4.5 km(3) yr(-1)) over the Indian states of Rajasthan, Punjab and Haryana (including Delhi). During our study period of August 2002 to October 2008, groundwater depletion was equivalent to a net loss of 109 km(3) of water, which is double the capacity of India's largest surface-water reservoir. Annual rainfall was close to normal throughout the period and we demonstrate that the other terrestrial water storage components (soil moisture, surface waters, snow, glaciers and biomass) did not contribute significantly to the observed decline in total water levels. Although our observational record is brief, the available evidence suggests that unsustainable consumption of groundwater for irrigation and other anthropogenic uses is likely to be the cause. If measures are not taken soon to ensure sustainable groundwater usage, the consequences for the 114,000,000 residents of the region may include a reduction of agricultural output and shortages of potable water, leading to extensive socioeconomic stresses. PMID:19675570

Rodell, Matthew; Velicogna, Isabella; Famiglietti, James S

2009-08-20

54

Satellite-based distance education in digital paradigm: ISRO perspective  

Microsoft Academic Search

The paper outlines the ISRO's perspective on effective use of digital technologies through satellite communication for societal applications with a special focus on distance education. The paper discusses the ISRO's journey from SITE (Satellite Instructional Television Experiment) to Edusat and explains how these experiences have been put into practice by integrating the modern digital technologies, which has helped in transforming

S. L. Rajashekhar; G. V. Ayyangar; R. Sharma

2010-01-01

55

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

PubMed

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

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

2011-08-01

56

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

57

Satellite-based Land Data Assimilation at NASA/GMAO  

NASA Astrophysics Data System (ADS)

Land surface conditions impact weather and climate. Soil moisture has long been shown to interact with the atmosphere, soil temperature is a key variable in weather and climate models and snow season characteristics affect weather and climate variability. A number of remote sensing observations directly or indirectly measure these dynamic land conditions and can be used to update large-scale land surface model integrations, which are in turn critical to improving weather and climate forecasts. Many recent advances in land data assimilation were achieved with ensemble-based Kalman filtering. The presentation will give an overview of the challenges and advantages of assimilating satellite observations into land surface models. Progress in the assimilation of surface soil moisture, land surface temperature, snow, and terrestrial water storage at the NASA Global Modeling and Assimilation Office (GMAO) will be discussed. Special attention will go towards the preparation for assimilation of brightness temperatures and retrieved soil moisture as obtained from the current Soil Moisture Ocean Salinity (SMOS) mission, and the plans for soil moisture assimilation from the future Soil Moisture Active Passive (SMAP) mission.

Reichle, R. H.; De Lannoy, G. J.; Draper, C.; Forman, B.; Koster, R. D.; Liu, Q.; Toure, A.

2011-12-01

58

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

Microsoft Academic Search

A satellite-based UV-DIAL measurement system would allow continuous global monitoring of ozone concentration in the upper atmosphere. However such systems remain difficult to implement because aerosol-scattering return signals for satellite-based lidars are very weak. A suitable system must produce high-energy UV pulses at multiple wavelengths with very high efficiency. For example, a nanosecond system operating at 10 Hz must generate

Darrell Jewell Armstrong; Arlee Virgil Smith

2003-01-01

59

The evolution of satellite-based remote-sensing capabilities in India  

Microsoft Academic Search

This paper describes the Indian experience in evolving a satellite-based remote-sensing system. The experimental Earth observation programme represented by the Bhaskara-1 and -2 satellites are discussed to highlight the different components of a satellite-based remote-sensing mission. This is followed by a presentation of the key elements of the Indian Remote Sensing (IRS) satellite mission with particular reference to the details

K. Kasturirangan

1985-01-01

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

A proposed architecture for a satellite-based mobile communications network - The lowest three layers  

NASA Technical Reports Server (NTRS)

Architecture for a commercial mobile satellite network is proposed. The mobile satellite system (MSS) is composed of a network management center, mobile terminals, base stations, and gateways; the functions of each component are described. The satellite is a 'bent pipe' that performs frequency translations, and it has multiple UHF beams. The development of the MSS design based on the seven-layer open system interconnection model is examined. Consideration is given to the functions of the physical, data link, and network layers and the integrated adaptive mobile access protocol.

Yan, T. Y.; Naderi, F. M.

1986-01-01

62

Protocol Support for a New Satellite-Based Airspace Communication Network  

NASA Technical Reports Server (NTRS)

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

Shang, Yadong; Hadjitheodosiou, Michael; Baras, John

2004-01-01

63

Constraints from atmospheric CO2 and satellite-based vegetation activity observations on current land carbon cycle trends  

NASA Astrophysics Data System (ADS)

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

Dalmonech, D.; Zaehle, S.

2012-11-01

64

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

65

Communication Communication  

E-print Network

Communication Seminar Stanford University April 16, 2001 1 #12; Wireless Communication Theory . Wireless communication theory is having a renaissance in the past decade. . Much of it is centered around how to communicate e#ectively over fading channels. . A modern view of communication over fading channels is emerging

Tse, David

66

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

67

Author's personal copy Satellite-based modeling of transpiration from the grasslands in the Southern Great  

E-print Network

Author's personal copy Satellite-based modeling of transpiration from the grasslands (MODIS) 2002 International H2O Project IHOP_2002 Southern Great Plains Vegetation Transpiration Model Vegetation Photosynthesis Model evaporation transpiration Data from the 2002 International H2O Project (IHOP

Niyogi, Dev

68

Satellite-based modeling of transpiration from the grasslands in the Southern Great Plains, USA  

E-print Network

Satellite-based modeling of transpiration from the grasslands in the Southern Great Plains, USA Project IHOP_2002 Southern Great Plains Vegetation Transpiration Model Vegetation Photosynthesis Model evaporation transpiration Data from the 2002 International H2O Project (IHOP_2002), which was conducted during

Pielke, Roger A.

69

Eliminating adjacent-channel interference in satellite-based General Packet Radio Service (GPRS) systems  

Microsoft Academic Search

This paper presents a method for eliminating adjacent-channel interference (ACI) in satellite-based General Packet Radio Service (GPRS) systems using a new fuzzy adaptive filters (FAF). We validate the reasons for using such a filter by analyzing the Bayesian detector in which some parameter uncertainties exist. A clustering method is used to adaptively design the parameters of the FAF. Simulation results

Qilian Liang

2002-01-01

70

Satellite-based detection and monitoring of phytoplankton blooms along the Oregon coast  

E-print Network

, termed CHLrel and FLHrel, respectively, describe the onset and advection of algal blooms as a functionSatellite-based detection and monitoring of phytoplankton blooms along the Oregon coast S. M. Mc to detect and monitor phytoplankton blooms in the Oregon coastal region. The resulting bloom products

White, Angelicque

71

A Satellite-Based Multi-Pollutant Index of Global Air Quality  

E-print Network

A Satellite-Based Multi-Pollutant Index of Global Air Quality Matthew J. Cooper* Randall V. Martin, Vancouver, BC, Canada. V6T 1Z3 Air Quality Processes Research Section, Environment Canada. Toronto, ON of the world. Recognition is growing of the need for a multipollutant approach to air quality to better

Martin, Randall

72

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

Microsoft Academic Search

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

Kevin P. Gallo; Jimmy O. Adegoke; Timothy W. Owen; Christopher D. Elvidge

2002-01-01

73

Transport and Evolution of a Pollution Plume from Northern China: A Satellite-Based Case Study  

E-print Network

Transport and Evolution of a Pollution Plume from Northern China: A Satellite-Based Case Study Can, USA 4 Goddard Earth Sciences and Technology Center, University of Maryland, Baltimore County, Maryland NE of Beijing. In this study OMI and MODIS satellite sensors are employed to look into this air

Dickerson, Russell R.

74

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

Microsoft Academic Search

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

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

2005-01-01

75

Assessing satellite-based start-of-season trends in the US High Plains  

NASA Astrophysics Data System (ADS)

To adequately assess the effects of global warming it is necessary to address trends and impacts at the local level. This study examines phenological changes in the start-of-season (SOS) derived from satellite observations from 1982–2008 in the US High Plains region. The surface climate-based SOS was also evaluated. The averaged profiles of SOS from 37° to 49°N latitude by satellite- and climate-based methods were in reasonable agreement, especially for areas where croplands were masked out and an additional frost date threshold was adopted. The statistically significant trends of satellite-based SOS show a later spring arrival ranging from 0.1 to 4.9 days decade?1 over nine Level III ecoregions. We found the croplands generally exhibited larger trends (later arrival) than the non-croplands. The area-averaged satellite-based SOS for non-croplands (i.e. mostly grasslands) showed no significant trends. We examined the trends of temperatures, precipitation, and standardized precipitation index (SPI), as well as the strength of correlation between the satellite-based SOS and these climatic drivers. Our results indicate that satellite-based SOS trends are spatially and primarily related to annual maximum normalized difference vegetation index (NDVI, mostly in summertime) and/or annual minimum NDVI (mostly in wintertime) and these trends showed the best correlation with six-month SPI over the period 1982–2008 in the US High Plains region.

Lin, X.; Hubbard, K. G.; Mahmood, R.; Sassenrath, G. F.

2014-10-01

76

Satellite-based observations of surface turbulent stress during severe weather  

E-print Network

Satellite-based observations of surface turbulent stress during severe weather Mark A. Bourassa The environment of severe marine weather is harsh: in situ and satellite observations of surface turbulent stresses are extremely difficult to acquire under such conditions. Even for fair weather conditions

77

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

78

A comprehensive design and performance analysis of LEO satellite quantum communication  

E-print Network

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

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

2012-01-01

79

Terrestrial Ecosystem Adaptation  

E-print Network

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

Mills, L. Scott

80

Drought Chasing from Space: Recent Innovations in Satellite-based Remote Sensing Tools  

E-print Network

,000+ weather station locations. Operational VegDRI Map Production Satellite Data* Climate Data* Biophysical Data • PASG • SOSA • Out of Season • 36-week SPI • self-calibrated PDSI • Land Use/Land Cover Type • Irrigation • Soil Available Water Capacity...Drought Chasing from Space: Recent Innovations in Satellite-based Tools Brian Wardlow Center for Advanced Land Management Information Technologies (CALMIT) and National Drought Mitigation Center (NDMC) University of Nebraska-Lincoln University...

Wardlow, Brian

2013-11-20

81

A VIRTUAL VALIDATION ENVIRONMENT FOR THE DESIGN OF AUTOMOTIVE SATELLITE BASED NAVIGATION SYSTEMS FOR URBAN CANYONS  

Microsoft Academic Search

Satellite based automotive navigation systems use range information to navigation satellites like GPS, Glonas and in the future Galileo to determine their location on earth. Range to satellites is determined by measuring the time dierence between signals send by satellite and received by the automotive navigation system. To determine a 3D-position at sucient accuracy with non-atomic clocks requires receiving at

Holger Rath; Peter Unger; Andreas Emde; David Gruner; Horst Salzwedel

82

Integrating satellite-based evapotranspiration with simulation models for irrigation management at the scheme level  

Microsoft Academic Search

Improvements in irrigation management are urgently needed in regions where water resources for irrigation are being depleted.\\u000a This paper combines a water balance model with satellite-based remote-sensing estimates of evapotranspiration (ET) to provide\\u000a accurate irrigation scheduling guidelines for individual fields. The satellite-derived ET was used in the daily soil water\\u000a balance model to improve accuracy of field-by-field ET demands and

C. Santos; I. J. Lorite; M. Tasumi; R. G. Allen; E. Fereres

2008-01-01

83

All solid-state high-efficiency source for satellite-based UV ozone DIAL  

Microsoft Academic Search

During the past several years Sandia National Laboratories has carried out proof-of-concept experiments to demonstrate tunable, efficient, high-energy ultraviolet nanosecond light sources for satellite-based ozone DIAL. We designed our UV sources to generate pulse energies > 200 mJ at 10 Hz in the range of 308-320 nm with optical-to-optical efficiency approaching 25%. We use sum-frequency generation to mix the 532

Darrell J. Armstrong; Arlee V. Smith

2005-01-01

84

All solid-state high-efficiency source for satellite-based UV ozone DIAL  

Microsoft Academic Search

During the past several years Sandia National Laboratories has carried out proof-of-concept experiments to demonstrate tunable, efficient, high-energy ultraviolet nanosecond light sources for satellite-based ozone DIAL. We designed our UV sources to generate pulse energies > 200 mJ at 10 Hz in the range of 308-320 nm with optical-to-optical efficiency approaching 25%. We use sum-frequency generation to mix the 532

Darrell Jewell Armstrong; Arlee Virgil Smith

2004-01-01

85

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

86

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

E-print Network

A new generation of satellite based solar irradiance calculation schemes R. W. Mueller, D. Piernavieja Instituto Tecnologico de Canarias, Spain Keywords: radiative transfer, solar irradiance, MSG irradiance calculation scheme, including the functional treatment of the diurnal variation of the solar

Heinemann, Detlev

87

Characterization of satellite based proxies for estimating nucleation mode particles over South Africa  

NASA Astrophysics Data System (ADS)

In this work satellite observations from the NASA's A-Train constellation were used to derive the values of primary emission and regional nucleation proxies over South Africa to estimate the potential for new particle formation. As derived in Kulmala et al. (2011), the satellite based proxies consist of source terms (NO2, SO2 and UV-B radiation), and a sink term describing the pre-existing aerosols. The first goal of this work was to study in detail the use of satellite aerosol optical depth (AOD) as a substitute to the in situ based condensation sink (CS). One of the major factors affecting the agreement of CS and AOD was the elevated aerosol layers that increased the value of column integrated AOD but not affected the in situ CS. However, when the AOD in the proxy sink was replaced by an estimate from linear bivariate fit between AOD and CS, the agreement with the actual nucleation mode number concentration improved somewhat. The second goal of the work was to estimate how well the satellite based proxies can predict the potential for new particle formation. For each proxy the highest potential for new particle formation were observed over the Highveld industrial area, where the emissions were high but the sink due to pre-existing aerosols was relatively low. Best agreement between the satellite and in situ based proxies were obtained for NO2/AOD and UV-B/AOD2, whereas proxies including SO2 in the source term had lower correlation. Even though the OMI SO2 boundary layer product showed reasonable spatial pattern and detected the major sources over the study area, some of the known minor point sources were not detected. When defining the satellite proxies only for days when new particle formation event was observed, it was seen that for all the satellite based proxies the event day medians were higher than the entire measurement period median.

Sundström, A.-M.; Nikandrova, A.; Atlaskina, K.; Nieminen, T.; Vakkari, V.; Laakso, L.; Beukes, J. P.; Arola, A.; van Zyl, P. G.; Josipovic, M.; Venter, A. D.; Jaars, K.; Pienaar, J. J.; Piketh, S.; Wiedensohler, A.; Chiloane, E. K.; de Leeuw, G.; Kulmala, M.

2014-10-01

88

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

89

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

90

Experiences from near-real-time satellite-based volcano monitoring in Central America: case studies at Fuego, Guatemala  

Microsoft Academic Search

Over the past decade, remote sensing has been used increasingly in the study of active volcanoes and their associated hazards. Ground?based remote sensing techniques, such as those aimed at the analysis of volcanic gases or fumarole temperatures, are now part of routine monitoring operations with additional satellite?based remote sensing methods. It is likely that the use of satellite?based systems will

P. W. Webley; M. J. Wooster; W. Strauch; J. A. Saballos; K. Dill; P. Stephenson; J. Stephenson; R. Escobar Wolf; O. Matias

2008-01-01

91

Inventory estimation on the massively parallel processor. [from satellite based images  

NASA Technical Reports Server (NTRS)

This paper describes algorithms for efficiently computing inventory estimates from satellite based images. The algorithms incorporate a one dimensional feature extraction which optimizes the pairwise sum of Fisher distances. Biases are eliminated with a premultiplication by the inverse of the analytically derived error matrix. The technique is demonstrated with a numerical example using statistics obtained from an actual Landsat scene. Attention was given to implementation of the Massively Parallel processor (MPP). A timing analysis demonstrates that the inventory estimation can be performed an order of magnitude faster on the MPP than on a conventional serial machine.

Argentiero, P. D.; Strong, J. P.; Koch, D. W.

1980-01-01

92

Evaluation of Clear Sky Models for Satellite-Based Irradiance Estimates  

SciTech Connect

This report describes an intercomparison of three popular broadband clear sky solar irradiance model results with measured data, as well as satellite-based model clear sky results compared to measured clear sky data. The authors conclude that one of the popular clear sky models (the Bird clear sky model developed by Richard Bird and Roland Hulstrom) could serve as a more accurate replacement for current satellite-model clear sky estimations. Additionally, the analysis of the model results with respect to model input parameters indicates that rather than climatological, annual, or monthly mean input data, higher-time-resolution input parameters improve the general clear sky model performance.

Sengupta, M.; Gotseff, P.

2013-12-01

93

Evaluation of Satellite-Based High Resolution Precipitation Products for Catchment Hydrologic Forecasting  

NASA Astrophysics Data System (ADS)

Recent advances in global precipitation estimation using satellite information make it a viable and, in many regions unique input alternative for hydrologic modeling and water resources management. However, differences in algorithms result in different precipitation estimates at various hydrologically relevant scales. This study evaluates the mean areal precipitation estimates derived from four satellite-based precipitation estimation products (3B42-RT, 3B42-V6, PERSIANN, and CMORPH) in comparison with radar-gauge multi-sensor precipitation estimates for use in stream flow forecasting at small watershed scale. The study was conducted over the 1489 km2 Siloam watershed within the Illinois River basin above Siloam Springs stream gauge. For the study duration (2003 to 2008), the mean areal 6-hour precipitation was computed over the watershed from each of the (0.25ox0.25o) four products and introduced to the lumped Sacramento Soil Moisture Accounting Model (SAC-SMA). A boot strapping approach was used to separate the study period into a calibration and a validation data set. The results of the simulation are then compared with observed discharge at the basin outlet. The results demonstrate that overall, satellite-based precipitation products are adequate input when the modeling objective is to capture large/high flow magnitude events. However, differences between the four products were observed and will be reported in the presentation.

Behrangi, A.; Khakbaz, B.; Jaw, T. C.; Imam, B.; Hsu, K.; Sorooshian, S.

2009-12-01

94

Coordinated ground-based and geosynchronous satellite-based measurements of auroral pulsations  

SciTech Connect

We describe a technique that uses a ground-based all-sky video camera and geosynchronous satellite-based plasma and energetic particle detectors to study ionosphere-magnetosphere coupling as it relates to the aurora. The video camera system was deployed in Eagle, Alaska for a seven month period at the foot of the magnetic field line that threads geosynchronous satellite 1989-046. Since 1989-046 corotates with the earth, its footprint remains nearly fixed in the vicinity of Eagle, allowing for routine continuous monitoring of an auroral field line at its intersections with the ground and with geosynchronous orbit. As an example of the utility of this technique, we present coordinated ground-based and satellite based observations during periods of auroral pulsations and compare this data to the predictions of both the relaxation oscillator theory and flow cyclotron maser theory for the generation of pulsating aurorae. The observed plasma and energetic particle characteristics at geosynchronous orbit during pulsating aurorae displays are found to be in agreement with the predictions of both theories lending further support that a cyclotron resonance mechanism is responsible for auroral pulsations.

Suszcynsky, David M.; Borovsky, Joseph E.; Thomsen, Michelle F.; McComas, David J.; Belian, Richard D.

1996-09-01

95

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

96

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...

97

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

98

Desert Storm communications  

Microsoft Academic Search

An overview of the communication network that supported Operation Desert Storm is presented. The system, which maintained a 98% availability rate, supported 700000 telephone calls and 152000 messages per day. More than 30000 radio frequencies were managed to provide necessary connectivity and to ensure minimum interference. The roles of communications satellites, switched networks and terrestrial systems, and packet-switched networks and

J. S. Toma

1992-01-01

99

Limitations of terrestrial life.  

NASA Technical Reports Server (NTRS)

Questions of the suitability of other planets in the solar system for terrestrial organisms are discussed. It is found that life forms similar to terrestrial organisms but modified to fit the prevailing conditions could exist on Venus, Mars, and Jupiter. Of these, only in the case of Jupiter is there any evidence that life would have been able to evolve. Life on Jupiter would be restricted to the clouds. It is pointed out that life may have developed on other celestial bodies in forms which are quite dissimilar to terrestrial organisms with regard to their biochemistry.

Molton, P.

1973-01-01

100

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

101

Satellite-based detection of volcanic sulphur dioxide from recent eruptions in Central and South America  

NASA Astrophysics Data System (ADS)

Volcanic eruptions can emit large amounts of rock fragments and fine particles (ash) into the atmosphere, as well as several gases, including sulphur dioxide (SO2). These ejecta and emissions are a major natural hazard, not only to the local population, but also to the infrastructure in the vicinity of volcanoes and to aviation. Here, we describe a methodology to retrieve quantitative information about volcanic SO2 plumes from satellite-borne measurements in the UV/Visible spectral range. The combination of a satellite-based SO2 detection scheme and a state-of-the-art 3D trajectory model enables us to confirm the volcanic origin of trace gas signals and to estimate the plume height and the effective emission height. This is demonstrated by case-studies for four selected volcanic eruptions in South and Central America, using the GOME, SCIAMACHY and GOME-2 instruments.

Loyola, D.; van Geffen, J.; Valks, P.; Erbertseder, T.; van Roozendael, M.; Thomas, W.; Zimmer, W.; Wißkirchen, K.

2008-01-01

102

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

PubMed Central

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

2010-01-01

103

Terrestrial Impact Structures  

NASA Astrophysics Data System (ADS)

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

Grieve, R. A. F.

104

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

105

Introduction to Satellite Communications Technology for NREN  

NASA Technical Reports Server (NTRS)

NREN requirements for development of seamless nomadic networks necessitates that NREN staff have a working knowledge of basic satellite technology. This paper addresses the components required for a satellite-based communications system, applications, technology trends, orbits, and spectrum, and hopefully will afford the reader an end-to-end picture of this important technology.

Stone, Thom

2004-01-01

106

Dietary characterization of terrestrial mammals  

PubMed Central

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

2014-01-01

107

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

108

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

109

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

110

Interworking evolution of mobile satellite and terrestrial networks  

NASA Astrophysics Data System (ADS)

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.

111

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

112

The Military Capabilities and Implications of China's Indigenous Satellite-Based Navigation System  

Microsoft Academic Search

China has orbited a three-satellite constellation for space-based navigation known as Beidou. This article uses the constellation geometry, as determined by the NORAD space-surveillance system and publicly available from NASA, to estimate the accuracy available to a user of the Beidou system. Limited in terrestrial coverage to roughly the Asian subcontinent, this system requires a user either to go through

Geoffrey Forden

2004-01-01

113

Spatial and temporal interpolation of satellite-based aerosol optical depth measurements over North America using B-splines  

Microsoft Academic Search

Satellite-based measurements of aerosol optical depth (AOD) over land are obtained from an inversion procedure applied to dense dark vegetation pixels of remotely sensed images. The limited number of pixels over which the inversion procedure can be applied leaves many areas with little or no AOD data. Moreover, satellite coverage by sensors such as MODIS yields only daily images of

Nicolas Pfister; Norman T. O'Neill; Martin Aube; Minh-Nghia Nguyen; Xavier Bechamp-Laganiere; Albert Besnier; Louis Corriveau; Geremie Gasse; Etienne Levert; Danick Plante

2005-01-01

114

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 ...

115

Development and Application of a Satellite-based Convective Cloud Object-Tracking Methodology: A Multipurpose Data Fusion Tool  

E-print Network

1 Development and Application of a Satellite-based Convective Cloud Object-Tracking Methodology cloud-objects from convective cloud infancy (as few as 3 GOES infrared (IR) pixels) into the mature (WDSS-II) object tracking capabilities. The system uses an IR- window based field as input to WDSS

Lakshmanan, Valliappa

116

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

E-print Network

of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, China, 5 State Key University of Forestry and Technology, Changsha, Hunan, China, 7 State Key Laboratory of VegetationSatellite-Based Analysis of Evapotranspiration and Water Balance in the Grassland Ecosystems

Chen, Jiquan

117

A satellite-based method for monitoring seasonality in the overstory leaf area index of Siberian larch forest  

Microsoft Academic Search

Reliable monitoring of the leaf area index (LAI) is required to further understand the carbon, water, and energy cycles of forests. In this study, we proposed a new satellite-based method to estimate the overstory LAI (LAIo) separately from the understory LAI (LAIu) for larch forests covering eastern Siberia. We modeled forest scenes representative of larch forest structure, with particular consideration

Hideki Kobayashi; Nicolas Delbart; Rikie Suzuki; Keiji Kushida

2010-01-01

118

Coreless Terrestrial Exoplanets  

E-print Network

Differentiation in terrestrial planets is expected to include the formation of a metallic iron core. We predict the existence of terrestrial planets that have differentiated but have no metallic core--planets that are effectively a giant silicate mantle. We discuss two paths to forming a coreless terrestrial planet, whereby the oxidation state during planetary accretion and solidification will determine the size or existence of any metallic core. Under this hypothesis, any metallic iron in the bulk accreting material is oxidized by water, binding the iron in the form of iron oxide into the silicate minerals of the planetary mantle. The existence of such silicate planets has consequences for interpreting the compositions and interior density structures of exoplanets based on their mass and radius measurements.

L. Elkins-Tanton; S. Seager

2008-08-13

119

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

120

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

121

An Evaluation of the Statistics of Rainfall Extremes of Satellite-based Precipitation Products Using Multifractals  

NASA Astrophysics Data System (ADS)

Rainfall time-series from the NCDC data base were used to estimate the spatial distribution of multifractal parameters associated with the statistics of extreme rainfall across the continental US both for the entire period of the historical record, and for the period 1980 onwards which coincides with the beginning of the so-called satellite-era of rainfall products commonly associated with SSMI. Concurrently, the same analysis was performed using the time-series of available satellite products at each grid point for different precipitation products including GPCP and more recently TRMM based multi-sensor products. Although these data sets have different record lengths which can, and do affect the estimation of multifractal parameters, our results provide a first continental-scale view of the of the statistical character of extreme rainfall from satellite-based rainfall products for different physiographic regions and climate regimes. Via comparison against the results obtained from raingauge observations, we begin to assess the potential utility of these data in regions of the world where ground-based observations are lacking.

Sun, X.; Barros, A. P.

2008-05-01

122

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

123

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

124

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

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

125

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

NASA Astrophysics Data System (ADS)

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

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

2009-09-01

126

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

127

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

128

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

129

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

130

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

131

Batteries for terrestrial applications  

SciTech Connect

Extensive research has been conducted in the design and manufacture of very long life vented and sealed maintenance free nickel-cadmium aircraft batteries. These batteries have also been used in a number of terrestrial applications with good success. This study presents an overview of the Ni-Cd chemistry and technology as well as detailed analysis of the advantages and disadvantages of the Ni-Cd couple for terrestrial applications. The performance characteristics of both sealed and vented Ni-Cd's are presented. Various charge algorithms are examined and evaluated for effectiveness and ease of implementation. Hardware requirements for charging are also presented and evaluated. The discharge characteristics of vented and sealed Ni-Cd's are presented and compared to other battery chemistries. The performance of Ni-Cd's under extreme environmental conditions is also compared to other battery chemistries. The history of various terrestrial applications is reviewed and some of the lessons learned are presented. Applications discussed include the NASA Middeck Payload Battery, Raytheon Aegis Missile System Battery, THAAD Launcher battery, and the Titan IV battery. The suitability of the Ni-Cd chemistry for other terrestrial applications such as electric vehicles and Uninterruptible Power Supply is discussed.

Kulin, T.M.

1998-07-01

132

Terrestrial cosmic rays  

Microsoft Academic Search

This paper reviews the basic physics of those cosmic rays which can affect terrestrial electronics. Cosmic rays at sea level consist mostly of neutrons, protons, pions, muons, electrons, and photons. The particles which cause significant soft fails in electronics are those particles with the strong interaction: neutrons, protons, and pions. At sea level, about 95% of these particles are neutrons.

James F. Ziegler

1996-01-01

133

The terrestrial silica pump.  

PubMed

Silicon (Si) cycling controls atmospheric CO(2) concentrations and thus, the global climate, through three well-recognized means: chemical weathering of mineral silicates, occlusion of carbon (C) to soil phytoliths, and the oceanic biological Si pump. In the latter, oceanic diatoms directly sequester 25.8 Gton C yr(-1), accounting for 43% of the total oceanic net primary production (NPP). However, another important link between C and Si cycling remains largely ignored, specifically the role of Si in terrestrial NPP. Here we show that 55% of terrestrial NPP (33 Gton C yr(-1)) is due to active Si-accumulating vegetation, on par with the amount of C sequestered annually via marine diatoms. Our results suggest that similar to oceanic diatoms, the biological Si cycle of land plants also controls atmospheric CO(2) levels. In addition, we provide the first estimates of Si fixed in terrestrial vegetation by major global biome type, highlighting the ecosystems of most dynamic Si fixation. Projected global land use change will convert forests to agricultural lands, increasing the fixation of Si by land plants, and the magnitude of the terrestrial Si pump. PMID:23300825

Carey, Joanna C; Fulweiler, Robinson W

2012-01-01

134

Terrestrials Dwarf Planets  

E-print Network

Terrestrials Gas Giants Ice Giants Dwarf Planets The Solar System #12;Neptune Uranus Saturn Jupiter & Helium atmospheres. #12;The Dwarf Planets are a new class of Solar System objects defined by the IAU Dwarf planets can have eccentric and highly inclined orbits. #12;The Solar System has 7 Giant Moons

Gaudi, B. Scott

135

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...

136

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...

137

The Terrestrial Silica Pump  

PubMed Central

Silicon (Si) cycling controls atmospheric CO2 concentrations and thus, the global climate, through three well-recognized means: chemical weathering of mineral silicates, occlusion of carbon (C) to soil phytoliths, and the oceanic biological Si pump. In the latter, oceanic diatoms directly sequester 25.8 Gton C yr?1, accounting for 43% of the total oceanic net primary production (NPP). However, another important link between C and Si cycling remains largely ignored, specifically the role of Si in terrestrial NPP. Here we show that 55% of terrestrial NPP (33 Gton C yr?1) is due to active Si-accumulating vegetation, on par with the amount of C sequestered annually via marine diatoms. Our results suggest that similar to oceanic diatoms, the biological Si cycle of land plants also controls atmospheric CO2 levels. In addition, we provide the first estimates of Si fixed in terrestrial vegetation by major global biome type, highlighting the ecosystems of most dynamic Si fixation. Projected global land use change will convert forests to agricultural lands, increasing the fixation of Si by land plants, and the magnitude of the terrestrial Si pump. PMID:23300825

Carey, Joanna C.; Fulweiler, Robinson W.

2012-01-01

138

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

139

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

140

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

141

Temporal Sensitivity of Satellite-Based Remote Sensing Products to Rainfall Pulse Events in Dryland Ecosystems  

NASA Astrophysics Data System (ADS)

Remote sensing data products provide spatially extensive data about physical hydrological and ecological processes. However, due to the timing of satellite flyovers and processing schemes used to produce the end-user data products, fully capturing the temporal dynamics of carbon and water fluxes is limited. This is particularly true in semi-arid upland environments, which are known to respond to high-intensity, low-frequency rainfall pulses. Here we compare in situ measurements of ecological and hydrological fluxes and states (carbon and evaporative flux, soil moisture) to remote sensing data for a similar period in several semi-arid sites, including grasslands and shrublands in both bimodal and unimodal precipitation regimes. This comparison is made based on the characteristic drydown times of soil moisture and evapotranspiration, compared to the characteristic compositing period of a commonly used remote sensing product (MODIS). We also examine the correlation between the timing of events in the MODIS data products and in the flux record. We show that the characteristic time-scales associated with precipitation events and responses fall within compositing periods in the MODIS record. From this, we gain a better understanding about the pulse dynamics in these systems and the ability of satellite-based sensors to detect those pulses. Understanding how the episodic flux events associated with rainfall pulses control the magnitude of carbon and water exchange between the land surface and atmosphere and how those flux events are detected by remote sensing, will allow researchers to develop more spatially extensive estimates of water and carbon cycling in drylands, which will subsequently aid management decisions for water resources as well as land use.

Neal, A. L.; Kurc, S. A.; Brooks, P. D.

2009-12-01

142

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

143

Investigation of Aerosol-Cloud Interactions based on Satellite Based Remote Sensing in Northeast Asia  

NASA Astrophysics Data System (ADS)

The subject of aerosol-cloud interactions has received prominent attention because of still higher uncertainty in estimating its climatic forcings and its possible climatic implications. Although the various studies on the aerosol indirect effect have been carried out all over the world, relatively few focuses have been put on the Northeast Asian region, which has suffered from a lot of anthropogenic air pollution and various kinds of aerosol compositions. Detailed and integrated careful observations are needed to understand the complex coupled mechanisms of aerosol-cloud interaction and its radiative forcing, but these strategies have not been applied to the region yet. The first step to aerosol indirect study in Northeast Asia is to have an overall understanding of the current state of aerosol and cloud optical properties derived from ground and satellite-based remote sensings available since 2001. First of all, there seem to be no annual increasing/decreasing trends of monthly-average aerosol optical depth (AOD) from MODIS in the downstream region of China, which is also confirmed by the aerosol robotic network (AERONET). In general, AOD showed the strong horizontal gradient from China to Korea, with no relevant systematic association with the effective radius and optical depth of the liquid-phase cloud, which might be attributable to the masking synoptic meteorological variations and the coarse horizontal grid (1 deg by 1 deg). Specific comparisons of AOD and the effective radius demonstrated the significant negative correlation only in summer and over the Yellow Sea, where the relative variability of cloud (e.g. cloud optical depth) appears to be suppressed and aerosol loadings tend to be significantly variable relative to other regions and other seasons, which could indicate the seasonal and spatial sensitivity of aerosol-cloud interactions. With regard to the cloud scale in addition to the above climatic perspective, an association of the cloud with aerosols has been eventually examined using Atmospheric Brown Cloud data in March 2005.

Kim, B.-G.; Kim, Y.-J.; Ho, C.-H.; Kim, S.-W.

2009-04-01

144

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

NASA Astrophysics Data System (ADS)

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

Jewett, Christopher P.; Mecikalski, John R.

2013-11-01

145

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

146

Arsenic Speciation of Terrestrial Invertebrates  

Microsoft Academic Search

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

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

2009-01-01

147

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

148

Public service communications  

NASA Technical Reports Server (NTRS)

The purpose of the paper is to construct, for detailed analysis, satellite and terrestrial communications delivery system models. Attention is given to the Public Service Communications Delivery System Architectural Study, that takes advantage of the extensive experience which exists among the public service experimenters. The Application Test Pilot is examined, which is a program designed to help awareness, in a practical sense, of the technology available and by the users innovative talents, adapts the technology to solve their problems.

Whalen, A. A.

1979-01-01

149

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

Microsoft Academic Search

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

Darrell J. Armstrong; Arlee V. Smith

2007-01-01

150

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

SciTech Connect

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

Myers, D. R.

2009-03-01

151

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

SciTech Connect

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. 12 refs.

Demetriades-shah, T.H.; Kanemasu, E.T.; Flitcroft, I.D.; Su, H. (Georgia Univ., Griffin (United States) Kansas State Univ., Manhattan (United States))

1992-11-01

152

Terrestrial Exoplanet Light Curves  

E-print Network

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

Eric Gaidos; Nicholas Moskovitz; Darren M. Williams

2005-11-23

153

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

SciTech Connect

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

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

1997-05-01

154

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

155

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

PubMed

A hybrid approach is proposed to estimate exposure to fine particulate matter (PM(2.5)) 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 PM(2.5) data from EPA sites. Extrapolating this relationship to the study domain resulted in 2.3 million predictions of PM(2.5) 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 PM(2.5). Daily estimates of PM(2.5) 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 PM(2.5) exposure. Our analysis suggests that the risk of AECOPD increases 2.3% with a unit increase in PM(2.5) exposure within 9 days and 0.05° (?5?km) distance lags. In the aggregated analysis, the exposed groups (who experienced exposure to PM(2.5) >15.4??g/m(3)) were 54% more likely to be admitted for AECOPD than the reference group. The hybrid approach offers greater spatiotemporal coverage and reliable characterization of ambient concentration than conventional in situ monitoring-based approaches. Thus, this approach can potentially reduce exposure misclassification errors in the conventional air pollution epidemiology studies. PMID:24045428

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

2013-01-01

156

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

157

Systematic Differences between Satellite-Based Presipitation Climatologies over the Tropical Oceans  

NASA Technical Reports Server (NTRS)

Since the beginning of the World Climate Research Program's Global Precipitation Climatology Project (GPCP) satellite remote sensing of precipitation has made dramatic improvements, particularly for tropical regions. Data from microwave and infrared sensors now form the most critical input to precipitation data sets and can be calibrated with surface gauges to so that the strengths of each data source can be maximized in some statistically optimal sense. It is clear however that there still remain significant uncertainties with satellite precipitation retrievals which limit their usefulness for many purposes. Systematic differences i'A tropical precipitation estimates have been brought to light in comparison activities such as the GPCP Algorithm Intercomparison Project and more recent Wetnet Precipitation Intercomparison Project 3. These uncertainties are assuming more importance because of the demands for validation associated with global climate modeling and data assimilation methodologies. The objective of the present study is to determine the physical basis for systematic differences in spatial structure of tropical precipitation as portrayed by several different satellite-based data sets. The study is limited to oceanic regions only and deals primarily with aspects of spatial variability. We are specifically interested in why MSU channel 1 and GPI precipitation differences are so striking over the Eastern Pacific ITCZ and why they both differ from other microwave emission-based precipitation estimates from SSM/I and a scattering-based deep convective ice index from MSU channel 2. Our results to date have shown that MSU channel I precipitation estimates are biased high over the Eastern Pacific ITCZ because of two factors: (1) the hypersensitivity of this frequency to cloud water in contrast to falling rain drops, and (2) unaccounted for scattering effects by precipitation-size ice which depresses the signal of the liquid water emission. Likewise, cold cloud top climatologies such as the GPI show an excess (a deficit) in estimated rainfall over the E. Pacific ITCZ (Warm Pool region). We show that these algorithms need to account for regionally varying heights (or temperatures) at which tropical convection detrains to form cirrus shields. A second objective we pursue is to identify variations in the macroscale cloud physical and thermodynamic properties of precipitation regimes" and relate these differences to tropical dynamical mechanisms of tropical heat and moisture balance. Finally, we interpret the algorithm differences and their associations with tropical dynamics in terms of WCRP GPCP goals for constructing precipitation climatologies.

Robertson, Frankin R.; Fitzjarrald, Dan; McCaul, Eugene W.

1999-01-01

158

Comparison of Satellite-based Basal and Adjusted Evapotranspiration for Several California Crops  

NASA Astrophysics Data System (ADS)

There is a continuing need to develop new sources of information on agricultural crop water consumption in the arid Western U.S. Pursuant to the California Water Conservation Act of 2009, for instance, the stakeholder community has developed a set of quantitative indicators involving measurement of evapotranspiration (ET) or crop consumptive use (Calif. Dept. Water Resources, 2012). Fraction of reference ET (or, crop coefficients) can be estimated from a biophysical description of the crop canopy involving green fractional cover (Fc) and height as per the FAO-56 practice standard of Allen et al. (1998). The current study involved 19 fields in California's San Joaquin Valley and Central Coast during 2011-12, growing a variety of specialty and commodity crops: lettuce, raisin, tomato, almond, melon, winegrape, garlic, peach, orange, cotton, corn and wheat. Most crops were on surface or subsurface drip, though micro-jet, sprinkler and flood were represented as well. Fc was retrospectively estimated every 8-16 days by optical satellite data and interpolated to a daily timestep. Crop height was derived as a capped linear function of Fc using published guideline maxima. These variables were used to generate daily basal crop coefficients (Kcb) per field through most or all of each respective growth cycle by the density coefficient approach of Allen & Pereira (2009). A soil water balance model for both topsoil and root zone, based on FAO-56 and using on-site measurements of applied irrigation and precipitation, was used to develop daily soil evaporation and crop water stress coefficients (Ke, Ks). Key meteorological variables (wind speed, relative humidity) were extracted from the California Irrigation Management Information System (CIMIS) for climate correction. Basal crop ET (ETcb) was then derived from Kcb using CIMIS reference ET. Adjusted crop ET (ETc_adj) was estimated by the dual coefficient approach involving Kcb, Ke, and incorporating Ks. Cumulative ETc_adj throughout each monitoring period was lower than cumulative ETb for most crops, indicating that effect of water stress tended to exceed that of soil evaporation relative to basal conditions. We present results from the analysis and discuss implications for operational use of satellite-based Kcb and ETcb estimates for agricultural water resource management.

Johnson, L.; Lund, C.; Melton, F. S.

2013-12-01

159

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

160

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

161

Satellite-based agroclimatic indicators to support real-time and strategic decisions in agricultural management  

NASA Astrophysics Data System (ADS)

The objective of the poster is to present our activity in the COST-734 Action, CLIVAGRI of collection of satellite based information on the actual state and longer-term evolution of vegetation cover. The main purpose of CLIVAGRI is the evaluation of possible impacts from climate change and variability on agriculture and the assessment of critical thresholds for various European areas. As one of its targets, sensitivity, adaptive capacity and vulnerability of European agriculture areas are evaluated to provide users with all the information needed to adapt their strategies to current and future climatic conditions. This covers the fields of farmer activity, public and private extension services and especially policy-maker decisions on short- and long-term bases. Under a changing climate, the role of agriculture as provider of environmental and ecosystem services will gain further importance. These services rely more and more on remotely sensed information, mainly gathered from meteorological and land surface imaging satellites. Satellite-derived variables already have a long record of monitoring crop production. The most relevant variables measured over land are: solar radiation, albedo, vegetation indices, leaf area index (LAI), land surface temperature (LST), rainfall, fires and burned area, snow cover and land use types. Some of these variables are required as inputs to give an immediate view of climate change impact for example. The most important parameters of this type are: vegetation indices and specifically the normalised difference vegetation index (NDVI), maximum and total greenness during the growing season, fraction of Photosynthetically Active Radiation and its absorbed proportion (FPAR and APAR) and the leaf area index (LAI). The present aim of the specific Working Group within the COST-734 is to prepare an intelligent inventory of the practically available agroclimatic indicators and to provide them together with general recommendations for their use, together with practical case studies. The results will be disseminated in order to significantly enhance awareness in the agricultural sector of the current hazard level and the perspectives related to the next few decades. Risk maps, graphics, tables, etc. will be used to provide the requested information to end-users. The current state of these activities will be displayed through this poster.

Toulios, L.; Mika, J.; Struzik, P.; Tsiros, E.; Dunkel, Z.; Stancalie, G.; Danson, F. M.

2009-04-01

162

Optical satellite communications in Europe  

NASA Astrophysics Data System (ADS)

This paper describes optical satellite communication activities based on technology developments, which started in Europe more than 30 years ago and led in 2001 to the world-first optical inter-satellite communication link experiment (SILEX). SILEX proved that optical communication technologies can be reliably mastered in space and in 2006 the Japanese Space Agency (JAXA) joined the optical inter-satellite experiment from their own satellite. Since 2008 the German Space Agency (DLR) is operating an inter-satellite link between the NFIRE and TerraSAR-X satellites based on a second generation of laser communication technology, which will be used for the new European Data Relay Satellite (EDRS) system to be deployed in 2013.

Sodnik, Zoran; Lutz, Hanspeter; Furch, Bernhard; Meyer, Rolf

2010-02-01

163

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

164

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

Microsoft Academic Search

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

Joseph S. Colburn; Yahya Rahmat-Samii

1998-01-01

165

Entanglement-based quantum communication over 144km  

E-print Network

, and is an essential step towards future satellite-based quantum communication and experimental tests on quantum cryptography to establish an unconditional secure key3­5 , in quantum teleportation6­10 to transfer quantum free-space links through the atmosphere. For time-bin entanglement a 10 km link was demonstrated

Loss, Daniel

166

Iridium: Global OTH data communications for high altitude scientific ballooning  

Microsoft Academic Search

While the scientific community is no stranger to embracing commercially available technologies, the growth and availability of truly affordable cutting edge technologies is opening the door to an entirely new means of global communications. For many years high altitude ballooning has provided science an alternative to costly satellite based experimental platforms. As with any project, evolution becomes an integral part

A. Denney

2004-01-01

167

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

168

With satellite-based air navigation imminent in the country, a navigation revolution is sweeping across India. Government of India has invested some Rs.  

E-print Network

need. Course Contents Coordinate transformations and kinematics Principles of Inertial Navigation Short-term error propagation with translation and rotation Advanced inertial navigation analysisMotivation With satellite-based air navigation imminent in the country, a navigation revolution

Narayanan, H.

169

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

E-print Network

[1] 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 ...

Yamana, Teresa K.

170

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

171

Comets and Terrestrial Magnetic Storms  

Microsoft Academic Search

A recent theory of the authors attributed terrestrial magnetic storms and auroral displays to the effect of unusual flares of ultra-violet light from the sun falling upon the terrestrial atmosphere. Such flares would be expected to cause changes in comets, and therefore comet changes should be closely connected with magnetic storms. This connection is supported by the evidence brought out

H. B. Maris; E. O. Hulburt

1929-01-01

172

Chapter 8 Terrestrial Biological Resources  

E-print Network

This chapter describes the environmental setting for terrestrial biological resources and the regulatory setting associated with these resources. It also evaluates environmental impacts on terrestrial biological resources that could result from the Lower San Joaquin River (LSJR) and southern Delta water quality (SDWQ) alternatives and, if applicable, offers mitigation measures that

unknown authors

173

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

174

Terrestrial Planet Geophysics  

NASA Astrophysics Data System (ADS)

Terrestrial planet geophysics beyond our home sphere had its start arguably in the early 1960s, with Keith Runcorn contending that the second-degree shape of the Moon is due to convection and Mariner 2 flying past Venus and detecting no planetary magnetic field. Within a decade, in situ surface geophysical measurements were carried out on the Moon with the Apollo program, portions of the lunar magnetic and gravity fields were mapped, and Jack Lorell and his colleagues at JPL were producing spherical harmonic gravity field models for Mars using tracking data from Mariner 9, the first spacecraft to orbit another planet. Moreover, Mariner 10 discovered a planetary magnetic field at Mercury, and a young Sean Solomon was using geological evidence of surface contraction to constrain the thermal evolution of the innermost planet. In situ geophysical experiments (such as seismic networks) were essentially never carried out after Apollo, although they were sometimes planned just beyond the believability horizon in planetary mission queues. Over the last three decades, the discipline of terrestrial planet geophysics has matured, making the most out of orbital magnetic and gravity field data, altimetric measurements of surface topography, and the integration of geochemical information. Powerful constraints are provided by tectonic and volcanic information gleaned from surface images, and the engagement of geologists in geophysical exercises is actually quite useful. Accompanying these endeavors, modeling techniques, largely adopted from the Earth Science community, have become increasingly sophisticated and have been greatly enhanced by the dramatic increase in computing power over the last two decades. The future looks bright with exciting new data sets emerging from the MESSENGER mission to Mercury, the promise of the GRAIL gravity mission to the Moon, and the re-emergence of Venus as a worthy target for exploration. Who knows? With the unflagging optimism and persistence of a few diehards, we may eventually have a seismic and heat flow network on Mars.

Phillips, R. J.

2008-12-01

175

The feasibility of tropospheric and total ozone determination using a Fabry-Perot interferometer as a satellite-based nadir-viewing atmospheric sensor  

NASA Astrophysics Data System (ADS)

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

176

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

177

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

178

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

NASA Technical Reports Server (NTRS)

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.

Jethva, H.; Torres, O.

2012-01-01

179

Reconfigurable Antennas for High Data Rate Multi-beam Communication Systems  

NASA Technical Reports Server (NTRS)

High-speed (2-100 Mb/sec) wireless data communication - whether land- or satellite-based - faces a major challenge: high error rates caused by interference and unpredictable environments. A planar antenna system that can be reconfigured to respond to changing conditions has the potential to dramatically improve data throughput and system reliability. Moreover, new planar antenna designs that reduce array size, weight, and cost can have a significant impact on terrestrial and satellite communication system performance. This research developed new individually-reconfigurable planar antenna array elements that can be adjusted to provide multiple beams while providing increased scan angles and higher aperture efficiency than traditional diffraction-limited arrays. These new elements are microstrip spiral antennas with specialized tuning mechanisms that provide adjustable radiation patterns. We anticipate that these new elements can be used in both large and small arrays for inter-satellite communication as well as tracking of multiple mobile surface-based units. Our work has developed both theoretical descriptions as well as experimental prototypes of the antennas in both single element and array embodiments. The technical summary of the results of this work is divided into six sections: A. Cavity model for analysis and design of pattern reconfigurable antennas; B. Performance of antenna in array configurations for broadside and endfire operation; C. Performance of antenna in array configurations for beam scanning operation; D. Simulation of antennas in infinite phased arrays; E. Demonstration of antenna with commercially-available RF MEMS switches; F. Design of antenna MEMS switch combinations for direct simultaneous fabrication.

Bernhard, Jennifer T.; Michielssen, Eric

2005-01-01

180

Communication Channels Communication Channels  

E-print Network

Communication Channels 1/79 #12;Communication Channels Channel c is described by message script Mc extended natural variable 2/79 #12;Communication Channels Channel c is described by message script Mc extended natural variable 3/79 #12;Communication Channels Channel c is described by message script Mc

Hehner, Eric C.R.

181

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

182

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

SciTech Connect

Interferometric Synthetic Aperture Radar (InSAR), gathered over the In Salah CO{sub 2} storage project in Algeria, provides an early indication that satellite-based geodetic methods can be effective in monitoring the geological storage of carbon dioxide. An injected volume of 3 million tons of carbon dioxide, from one of the first large-scale carbon sequestration efforts, produces a measurable surface displacement of approximately 5 mm/year. Using geophysical inverse techniques we are able to infer flow within the reservoir layer and within a seismically detected fracture/ fault zone intersecting the reservoir. We find that, if we use the best available elastic Earth model, the fluid flow need only occur in the vicinity of the reservoir layer. However, flow associated with the injection of the carbon dioxide does appear to extend several kilometers laterally within the reservoir, following the fracture/fault zone.

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

2009-10-15

183

Telemammography Using Satellite Communications  

NASA Technical Reports Server (NTRS)

Telemammography, the electronic transmission of digitized mammograms, can connect patients with timely, critical medical expertise; howev er, an adequate terrestrial communications infrastructure does not exist in these areas. NASA Lewis Research Center's Advanced Space Commu nications Laboratory is now working with leading breast cancer resear ch hospitals, including the Cleveland Clinic and the University of Virginia, to perform the critical research necessary to allow new satell ite networks to support telemammography.

1996-01-01

184

USING TERRESTRIAL PLANTS IN BIOMONITORING  

EPA Science Inventory

Terrestrial plants have been used as monitors of environmental pollutants since at least the beginning of this century & have recently received attention in response to the need for ecological assessments at hazardous waste sites & monitoring pesticide damage to nontarget plants....

185

Radiocarbon dating of terrestrial carbonates  

USGS Publications Warehouse

Terrestrial carbonates encompass a wide range of materials that potentially could be used for radiocarbon (14C) dating. Biogenic carbonates, including shells and tests of terrestrial and aquatic gastropods, bivalves, ostracodes, and foraminifera, are preserved in a variety of late Quaternary deposits and may be suitable for 14C dating. Primary calcareous deposits (marls, tufa, speleothems) and secondary carbonates (rhizoliths, fracture fill, soil carbonate) may also be targeted for dating when conditions are favorable. This chapter discusses issues that are commonly encountered in 14C dating of terrestrial carbonates, including isotopic disequilibrium and open-system behavior, as well as methods used to determine the reliability of ages derived from these materials. Recent methodological advancements that may improve the accuracy and precision of 14C ages of terrestrial carbonates are also highlighted.

Pigati, Jeffrey S.

2014-01-01

186

GEOLogic: Terrestrial and Jovian Planets  

NSDL National Science Digital Library

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

Guertin, Laura

187

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

188

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

189

COMMUNICATIONS ANNEX B -COMMUNICATIONS  

E-print Network

communications amongst emergency responders. The Annex is written in support of the Texas A&M University (TAMU and interoperable communications systems are essential to obtain the most complete information during emergency During emergency operations, the ICP or the CEOC, if activated, will serve as the communications center

190

Transmission Communication  

E-print Network

ELEC3028 Digital Transmission -- MODEM S Chen Digital Communication System . Purpose: communicate Communication System (continue) . A pair of transmitter (coder, modulator) and receiver (demodulator, decoder) is called transceiver . Information theory provides us basic communication theory for communication system

Chen, Sheng

191

Proactive TCP mechanism to improve Handover performance in Mobile Satellite and Terrestrial Networks  

E-print Network

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...

Vinayakray-Jani, Preetida

2012-01-01

192

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

NASA Astrophysics Data System (ADS)

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 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 dataset 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. Giovanni provides a simple way to visualize, analyze and access vast amounts of satellite-based Earth science data. Giovanni's features and practical examples of its use will be demonstrated, with an emphasis on how satellite remote sensing can help students understand recent events in the atmosphere and biosphere. Giovanni is actually a series of sixteen similar web-based data interfaces, each of which covers a single satellite dataset (such as TRMM, TOMS, OMI, AIRS, MLS, HALOE, etc.) or a group of related datasets (such as MODIS and MISR for aerosols, SeaWIFS and MODIS for ocean color, and the suite of A-Train observations co-located along the CloudSat orbital path). Recently, ground-based datasets have been included in Giovanni, including the Northern Eurasian Earth Science Partnership Initiative (NEESPI), and EPA fine particulate matter (PM2.5) for air quality. Model data such as the Goddard GOCART model and MERRA meteorological reanalyses (in process) are being increasingly incorporated into Giovanni to facilitate model- data intercomparison. A full suite of data analysis and visualization tools is also available within Giovanni. The GES DISC is currently developing a systematic series of training modules for Earth science satellite data, associated with our development of additional datasets and data visualization tools for Giovanni. Training sessions will include an overview of the Earth science datasets archived at Goddard, an overview of terms and techniques associated with satellite remote sensing, dataset-specific issues, an overview of Giovanni functionality, and a series of examples of how data can be readily accessed and visualized.

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

2008-12-01

193

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

194

Utilization of the terrestrial cyanobacteria  

NASA Astrophysics Data System (ADS)

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

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

195

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

Microsoft Academic Search

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

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

2008-01-01

196

Communication Methods What is Communication?  

E-print Network

1 Communication Methods What is Communication? Communication involves sharing ideas, information, sounds or images. Communicating over a distance requires three stages: encoding, transmission language, used quipus to communicate numeric information. A quipu was a method of encoding numbers

Simonson, Shai

197

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)...

198

Convergence of Phenological and Physiological Control on Annual Terrestrial Carbon Dioxide Uptake  

NASA Astrophysics Data System (ADS)

Despite enormous variations in vegetation type, climate, and soil from tropics to tundra, we found terrestrial gross primary production (GPP) is fundamentally under a joint control of the length of CO2 uptake period (CUP) and seasonal physiological maximal capacity of CO2 uptake (GPPmax). Across 213 globally distributed sites of eddy covariance, the ratio (?) of terrestrial annual GPP to the product of CUP and GPPmax converges to a quite narrow range (90% values in 0.61-0.83). In North America, the satellite-based ? converges to 0.60-0.70 in most regions ranging from the Arctic down to the middle of the U.S., and gradually increases toward 1.0 in the tropical regions in the west coast of Mexico and the Caribbean region. The changes in averaged annual GPP across North America from 2000 to 2010 cannot be explained by either GPPmax or CUP alone, but is well interpreted by their combination. We further detected the recent increasing trends in annual GPP in North America is more contributed by CUP in northwestern Canada but by GPPmax in most other regions. In most biomes and regions, GPPmax is more important than CUP in regulating the spatiotemporal variability of terrestrial annual GPP. Although the causes for the converged ? remain unclear, it may be largely determined by the co-variation between the lengths of CUP and the stable phase of GPPmax. Our findings provide significant insights into the underlying mechanism of variations in terrestrial annual GPP, which can improve our understanding of the intricate GPP responses to the ongoing multiple-factor environmental changes and the large uncertainty in predicted future land CO2 uptake among different terrestrial biosphere models.

Xia, J.; Luo, Y.; Niu, S.; Hui, D.; Dong, J.; Chen, J.; Weng, E.; Li, J.

2013-12-01

199

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

200

Basaltic volcanism in terrestrial planets  

NASA Technical Reports Server (NTRS)

A prescription is presented of a 3-year experimental project designed to encourage a selected group of earth scientists to think on a Solar System scale rather than a terrestrial, lunar, or martian scale. Basaltic volcanism was the process selected because it manifests itself widely in the inner Solar System and because it seemed more cleanly separable from other geological problems than other processes considered. Studies in ten areas are to illuminate all aspects of the mechanics and chronology of the generation and eruption of basaltic lavas in the terrestrial planets. Attention is given to individual team reports related to the various areas.

Wood, J. A.

1977-01-01

201

Space Physics and Terrestrial Effects  

NSDL National Science Digital Library

This curriculum guide is intended for high school teachers who are teaching solar physics, especially the effects of solar activity on terrestrial planets. The chapters discuss stellar evolution, the structure of the sun, studying the sun, and solar and terrestrial interactions. Lab activities provided include: building a spectroscope, energy transport within the sun, measuring the solar constant, luminosity of the sun and stars, seeing different wavelengths, the Earth-Sun orientation, the effect of the solar wind on the geomagnetic field, determining the rotation period of the sun, and radiation hazards in space.

2005-05-23

202

The Evolution of Operational Satellite Based Remote Sensing in Support of Weather Analysis, Nowcasting, and Hazard Mitigation  

NASA Astrophysics Data System (ADS)

The mission of the National Oceanic and Atmospheric Administration (NOAA) National Environmental Data Information Service (NESDIS) is to provide timely access to global environmental data from satellites and other sources to promote, protect, and enhance America’s economy, security, environment, and quality of life. To fulfill its responsibilities, NESDIS acquires and manages America’s operational environmental satellites, operates the NOAA National Data Centers, provides data and information services including Earth system monitoring, performs official assessments of the environment, and conducts related research. The Nation’s fleet of operational environmental satellites has proven to be very critical in the detection, analysis, and forecast of natural or man-made phenomena. These assets have provided for the protection of people and property while safeguarding the Nation’s commerce and enabling safe and effective military operations. This presentation will take the audience through the evolution of operational satellite based remote sensing in support of weather forecasting, nowcasting, warning operations, hazard detection and mitigation. From the very first experiments involving radiation budget to today’s fleet of Geostationary and Polar Orbiting satellites to tomorrow’s constellation of high resolution imagers and hyperspectral sounders, environmental satellites sustain key observations for current and future generations.

Hughes, B. K.

2010-12-01

203

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.

204

An assessment of satellite-based high resolution precipitation datasets for atmospheric composition studies in the maritime continent  

NASA Astrophysics Data System (ADS)

The Maritime Continent (MC) region of Southeast Asia is known for land use practices that are modulated by precipitation occurrence and fire activity. The polluted environment may modify cloud/precipitation formation mechanisms, but meteorological or weather patterns may disrupt or otherwise influence these same processes. Since the simultaneous retrieval of precipitation and aerosol properties is not possible from current satellite observations, the choice of the precipitation dataset used for applications such as model assimilation and scavenging in aerosol transport models could provide very different results. In this article, a seven-year (2003-2009) time period was analyzed with five satellite-based high-resolution precipitation products (HRPP), the MERRA model reanalysis, and MODIS-derived aerosol observations within nine Southeast Asia domains. Substantially different trends between the aerosol concentration and precipitation time series were noted for different MC island regions, as well as HRPP differences in the precipitation diurnal variability and their capability to track precipitation extremes. For all regions, the most noticeable change to the diurnal cycle was noted during the genesis phase (Phase 1 in the MC) of the intraseasonal Madden Julian Oscillation (MJO). Since these studies do not take any aerosol transport or precipitation dynamics into account, the use of Lagrangian models is proposed to study non-localized aerosol/precipitation interactions and better establish their veracity in current model simulations.

Turk, F. Joseph; Xian, Peng

2013-03-01

205

Swimming with robots: Human robot communication at depth  

Microsoft Academic Search

Human-robot communication is a complex problem even in the terrestrial domain. Failure to properly communicate instructions to a robot and receive appropriate feedback can at the very least hamper the ability of the robot to perform its task, and at worst prevent the task from being completed. The problem of providing effective communication between a robot and its operator becomes

Bart Verzijlenberg; Michael Jenkin

2010-01-01

206

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

207

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

208

Terrestrial Behavior of Ateles spp  

Microsoft Academic Search

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

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

2005-01-01

209

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

210

Ionospheres of the terrestrial planets  

Microsoft Academic Search

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

R. W. Schunk; A. F. Nagy

1980-01-01

211

The Terrestrial Planets Large Bodies  

E-print Network

[MESSENGER] Hot Spot Shield Volcanoes on Mars [NASA MGS] Evidence of past volcanism on Mercury and Mars #12, extinct shield volcanoes. #12;Solid inner core Liquid outer core The large terrestrial planets cool more) on the Moon Lava plains and volcanic vents on Mercury Hot-spot volcanoes on Mars Crustal Shaping: Primary

Gaudi, B. Scott

212

Provenance of the terrestrial planets.  

PubMed

Earlier work on the simultaneous accumulation of the asteroid belt and the terrestrial planets is extended to investigate the relative contribution to the final planets made by material from different heliocentric distances. As before, stochastic variations intrinsic to the accumulation processes lead to a variety of final planetary configurations, but include systems having a number of features similar to our solar system. Fifty-nine new simulations are presented, from which thirteen are selected as more similar to our solar system than the others. It is found that the concept of "local feeding zones" for each final terrestrial planet has no validity for this model. Instead, the final terrestrial planets receive major contributions from bodies ranging from 0.5 to at least 2.5 AU, and often to greater distances. Nevertheless, there is a correlation between the final heliocentric distance of a planet and its average provenance. Together with the effect of stochastic fluctuations, this permits variation in the composition of the terrestrial planets, such as the difference in the decompressed density of Earth and Mars. Biologically important light elements, derived from the asteroidal region, are likely to have been significant constituents of the Earth during its formation. PMID:11539576

Wetherill, G W

1994-01-01

213

Water wave communication in the genus Bombina (amphibia)  

Microsoft Academic Search

Amphibians were phylogenetically the first vertebrates to leave the aquatic environment and cope with terrestrial conditions including effects of gravity and substrate on movement and communication. Studies of extant primitive amphibians, which have conserved ancestral morphology and behavior, may help us to understand how gravitational adaptation from aquatic to terrestrial environments occurred. The anuran genus Bombina is a candidate for

B. Seidel; M. Yamashita; I.-H. Choi; J. Dittami

2001-01-01

214

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

215

The Interplanetary Internet: A Communications Infrastructure for Mars Exploration  

Microsoft Academic Search

A successful program of Mars Exploration will depend heavily on a robust and dependable space communications infrastructure that is well integrated with the terrestrial Internet. In the same way that the underpinnings of the Internet are the standardized \\

S. Burleigh; V. Cerf; R. Durst; K. Fall; A. Hooke; K. Scott; H. Weiss

2002-01-01

216

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

217

Real-time global flood estimation using satellite-based precipitation and a coupled land surface and routing model  

NASA Astrophysics Data System (ADS)

widely used land surface model, the Variable Infiltration Capacity (VIC) model, is coupled with a newly developed hierarchical dominant river tracing-based runoff-routing model to form the Dominant river tracing-Routing Integrated with VIC Environment (DRIVE) model, which serves as the new core of the real-time Global Flood Monitoring System (GFMS). The GFMS uses real-time satellite-based precipitation to derive flood monitoring parameters for the latitude band 50°N-50°S at relatively high spatial (˜12 km) and temporal (3 hourly) resolution. Examples of model results for recent flood events are computed using the real-time GFMS (http://flood.umd.edu). To evaluate the accuracy of the new GFMS, the DRIVE model is run retrospectively for 15 years using both research-quality and real-time satellite precipitation products. Evaluation results are slightly better for the research-quality input and significantly better for longer duration events (3 day events versus 1 day events). Basins with fewer dams tend to provide lower false alarm ratios. For events longer than three days in areas with few dams, the probability of detection is ˜0.9 and the false alarm ratio is ˜0.6. In general, these statistical results are better than those of the previous system. Streamflow was evaluated at 1121 river gauges across the quasi-global domain. Validation using real-time precipitation across the tropics (30°S-30°N) gives positive daily Nash-Sutcliffe Coefficients for 107 out of 375 (28%) stations with a mean of 0.19 and 51% of the same gauges at monthly scale with a mean of 0.33. There were poorer results in higher latitudes, probably due to larger errors in the satellite precipitation input.

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

2014-03-01

218

A Satellite-Based Method for Estimating Global Oceanic DMS and Its Application in a 3-D Atmospheric GCM  

SciTech Connect

The flux of dimethylsulfide (DMS) from the world's oceans is the largest known source of biogenically-derived reduced sulfur compounds to the atmosphere. Its impact on atmospheric chemistry and radiative transfer is an active area of scientific research, and DMS is routinely included in three-dimensional global climate change and chemical transport models. In such models, DMS fluxes typically are based on global sea surface DMS concentrations and wind-speed-dependent parameterizations of the mass transfer coefficient. We show here how sea surface DMS concentrations can be estimated from satellite-based Sea-viewing Wide Field-of-View Sensor (SeaWiFS) observations of sea surface chlorophyll a. We compare SeaWiFS-derived DMS concentrations for the twelve month period November 1997 through October 1998 with shipboard measurements made in the Pacific and Indian Oceans. The SeaWiFS-derived DMS distributions demonstrate improved capture of DMS spatial variability in Southern Ocean surface waters relative to previous works, but underestimate the amplitude of seasonal DMS variations in this region. Using the three-dimensional Atmospheric General Circulation Model of the Laboratoire de M?orologie Dynamique, model-time-step wind speeds, an atmospheric-stability-dependent parameterization of the mass transfer coefficient, and our SeaWiFS-derived oceanic DMS distributions, we estimate an annual Southern Ocean DMS emission of 6.8 Tg S yr-1. This value represents approximately one-third of the annual global DMS marine emission, and underscores the importance of this region as a source of natural sulfur emissions.

Belviso, S.; Moulin, C.; Bopp, L.; Cosme, E.; Chapman, Elaine G.; Aranami, K.

2003-01-01

219

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

220

Jan 23 Terrestrial Forest Biomes of the World Terrestrial Forest Biomes of the World  

E-print Network

Jan 23 Terrestrial Forest Biomes of the World #12;Terrestrial Forest Biomes of the World Chapin et al. 2011. Fig 2.24 #12;Terrestrial Forest Biomes of the World Chapin et al. 2011. Fig 2.24 Biome Wildlife Fund Terrestrial Biomes and Biogeographic Realms of the World #12;Climate Controls on Biomes

Hansen, Andrew J.

221

Global Flush Communication Primitive Communication  

E-print Network

Global Flush Communication Primitive Communication for Inter-process Ashwani Gahlot Mohan Ahuja IBM Carlson The Ohio State University Columbus, Abstract We propose a global flush communication prim- itive, Asynchronous distributed systwns, Distributed algorithm, Group communication, Global flush, Termination

Carlson, Timothy J.

222

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

223

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

E-print Network

Far-IR semiconductor laser for future THz-carrier free-space communications R. E. Peale*a , A. V prospects for application to secure satellite and short-range terrestrial free-space communications on a THz, satellite communication 1. INTRODUCTION Free space communications using THz carrier frequencies is severely

Peale, Robert E.

224

Alien Terrestrial Invertebrates of Europe  

Microsoft Academic Search

Unlike other groups of animals and plants, no checklist of alien terrestrial invertebrates was available in any of the European\\u000a countries until recently. Since 2002, such checklists were successively provided by Austria (Essl and Rabitsch 2002), Germany\\u000a (Geiter et al. 2002), the Czech Republic (Šefrová and Lašt? vka 2005), Scandinavia (NOBANIS 2007), the United Kingdom (Hill\\u000a et al. 2005), Switzerland

Alain Roques; Wolfgang Rabitsch; Jean-Yves Rasplus; Carlos Lopez-Vaamonde; Wolfgang Nentwig; Marc Kenis

225

47 CFR 25.255 - Procedures for resolving harmful interference related to operation of ancillary terrestrial...  

Code of Federal Regulations, 2010 CFR

Procedures for resolving harmful interference related to operation of ancillary terrestrial components operating in the 1.5./1.6 GHz, 1.6/2.4 GHz and 2 GHz bands. 25.255 Section 25.255 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER...

2010-10-01

226

Seasonal and Spatial Comparisons between Cloud and Aerosol Optical Properties Derived from Satellite Based Remote Sensing in Northeast Asia  

NASA Astrophysics Data System (ADS)

The subject of aerosol-cloud interactions has received prominent attention because of still higher uncertainty in estimating its climatic forcings and its possible climatic implications. Aerosol chemical and physical properties, cloud dynamic and turbulent characteristics, and the aerosol-cloud interactions should be considered together when evaluating the aerosol indirect effects, since the underlying mechanisms appear to be dependent upon each other, and accounting for them is impossible with the current understanding of aerosol indirect effect. Although the various studies on the aerosol indirect effect have been carried out all over the world, relatively few focuses have been put on the Northeast Asian region, which has frequently suffered from the transport of various anthropogenic air pollutants, that probably could have an influence on cloud properties and further the associated climate forcing. Detailed and integrated careful observations are needed to understand the complex coupled mechanisms of aerosol-cloud interaction and its radiative forcing, but these strategies have not been applied to the region yet. The first step to aerosol indirect study in Northeast Asia is to have an overall understanding of the current state of aerosol and cloud optical properties derived from ground- and satellite-based remote sensings available since around early 2000, which eventually could provide the basic ground for both aerosol and cloud communities. First of all, there seem to be no annual increasing/decreasing trends of monthly-average aerosol optical depth (AOD) from MODIS (MOD08) in the downstream region of China, which is also confirmed by the aerosol robotic network (AERONET). In general, AOD showed the strong horizontal gradient from China to Korea, with no relevant systematic association with the effective radius and optical depth of the liquid-phase cloud, which might be attributable to the masking synoptic meteorological variations and the coarse horizontal grid. Specifically comparisons of AOD and the effective radius demonstrated the significant negative correlation only in summer and over the Yellow Sea, indicating the seasonal and spatial sensitivity of aerosol- cloud interactions.

Kim, B.; Kim, Y.; Ho, C.; Song, C.

2008-12-01

227

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

228

Use of satellite-based aerosol optical depth and spatial clustering to predict ambient PM2.5 concentrations.  

PubMed

Satellite-based PM(2.5) monitoring has the potential to complement ground PM(2.5) monitoring networks, especially for regions with sparsely distributed monitors. Satellite remote sensing provides data on aerosol optical depth (AOD), which reflects particle abundance in the atmospheric column. Thus AOD has been used in statistical models to predict ground-level PM(2.5) concentrations. However, previous studies have shown that AOD may not be a strong predictor of PM(2.5) ground levels. Another shortcoming of remote sensing is the large number of non-retrieval days (i.e., days without satellite data available) due to clouds and snow- and ice-cover. In this paper we propose statistical approaches to overcome these two shortcomings, thereby making satellite imagery a viable method to estimate PM(2.5) concentrations. First, we render AOD a robust predictor of PM(2.5) mass concentration by introducing an AOD daily calibration approach through the use of mixed effects model. Second, we develop models that combine AOD and ground monitoring data to predict PM(2.5) concentrations during non-retrieval days. A key feature of this approach is that we develop these prediction models separately for groups of days defined by the observed amount of spatial heterogeneity in concentrations across the study region. Subsequently, these methodologies were applied to examine the spatial and temporal patterns of daily PM(2.5) concentrations for both retrieval days (i.e., days with satellite data available) and non-retrieval days in the New England region of the United States during the period 2000-2008. Overall, for the years 2000-2008, our statistical models predicted surface PM(2.5) concentrations with reasonably high R(2) (0.83) and low percent mean relative error (3.5%). Also the spatial distribution of the estimated PM(2.5) levels in the study domain clearly exhibited densely populated and high traffic areas. The method we have developed demonstrates that remote sensing can have a tremendous impact on the fields of environmental monitoring and human exposure assessment. PMID:22841416

Lee, Hyung Joo; Coull, Brent A; Bell, Michelle L; Koutrakis, Petros

2012-10-01

229

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

230

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.

231

INTERNATIONAL COMMUNICATION  

E-print Network

TOOLS FOR INTERNATIONAL COMMUNICATION Joan Crowley Laurence Steinman June 24, 2014 #12;What is Communication? #12;What is Communication? - a process by which information is exchanged between individuals with communication is the illusion that it has taken place. � George Bernard Shaw #12;LANGUAGE When communicating

Di Pillo, Gianni

232

Evaluation of GRACE data using terrestrial gravity observations  

NASA Astrophysics Data System (ADS)

The GRACE twin satellite mission has been running since March, 2002 and now seven years of time-dependent global gravity field solutions are available. The sensitivity of the GRACE data is that they can detect variation in continental hydrology in the range of several ?Gal. However, there is still argument how to filter and rescale the GRACE gravity data. During the recent past, different filtering methods have been developed. GRACE solutions provided by different institutions show 15 % discrepancies in the annual cycle for the Amazon area (Bruinsma et al. 2009). Other types of observations, such as superconducting gravimeter (SG) combined with repeated absolute gravity (AG) measurements, offer the opportunity to evaluate the filtered and rescaled satellite data. By these constraints for post-processing treatment of GRACE solutions can be derived as well as information on the significance of GRACE-based temporal gravity changes will be gained. For this assessment it is necessary to bridge the gap in the spatial and temporal resolution of the terrestrial and satellite-based time series. Empirical Orthogonal Functions (EOFs) are used to overcome the different resolutions. For comparisons of the signal content, coherence and principal component analyses of the data sets are carried out. In this study, GFZ, JPL, CSR, and CNES/CRGS RL-2 GRACE solutions are used and for the filtering techniques a non-isotropic filter presented by Kusche (2007, 2009) and Gaussian filter for various radii are compared. From coherence analyses between SG and GRACE time series, good coherence is found for the periods of longer than semi-annual.

Abe, Maiko; Kroner, Corinna; Foerste, Christoph; Weise, Adelheid; Guentner, Andreas; Creutzfeldt, Benjamin; Jahr, Thomas; Jentzsch, Gerhard; Wilmes, Herbert; Wziontek, Hartmut

2010-05-01

233

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

234

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

235

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

236

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

237

MODIS-Derived Terrestrial Primary Production  

Microsoft Academic Search

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

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

238

Information communication  

E-print Network

Codes November 30, 2005 Erasure Channels 1 . In many practical communication systems, information, HDTV and in communication with Voyager, Gallileo and other space satellites. Luby Transform (LT) Codes

Roweis, Sam

239

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

240

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. 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

241

Widespread Wolbachia infection in terrestrial isopods and other crustaceans 123 Widespread Wolbachia infection in terrestrial isopods  

E-print Network

Widespread Wolbachia infection in terrestrial isopods and other crustaceans 123 Widespread Wolbachia infection in terrestrial isopods and other crustaceans Richard Cordaux1 , Samuel Pichon1,3 , Houda Wolbachia infection in terrestrial isopods and other crustaceans. In: Strus J, Taiti S, Sfenthourakis S (Eds

Richard, Cordaux,

242

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

243

US Air Force communications in Desert Storm  

Microsoft Academic Search

The US Central Command Air Forces' (USCENTAF) communications network for Operations Desert Shield and Desert Storm is described. The Central Command Air Forces network utilized 27 SatCom terminals, 27 automatic switches, and 27 terrestrial links and had the responsibility of providing air traffic services across six countries at 24 locations handling 350000 flight operations. The system complexity and air traffic

D. D. McKenzie

1992-01-01

244

Transracial Communication.  

ERIC Educational Resources Information Center

This book explores and explains communication among different racial groups within the scope of existing communication theory. Following a brief introduction, chapters cover "Directions in Transracial Communication" (definitions, process, structurization, and purpose); "Culture and Transracial Communication" (a viewpoint on culture, time, family,…

Smith, Arthur L.

245

Collisional Evolution of Terrestrial Planets  

NASA Astrophysics Data System (ADS)

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

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

2003-05-01

246

Collisional Evolution of Terrestrial Planets  

NASA Astrophysics Data System (ADS)

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

Agnor, C.; Asphaug, E.

2004-12-01

247

Cost Consideration for Future Communications Satellite  

NASA Astrophysics Data System (ADS)

This paper discusses the cost driving factors of the future communications satellite rather than discussing its cost itself directly, in terms of development period of time, services, and R&D by government. In the first, a period of time for development of a communications system is discussed in comparison of satellite communications system with a terrestrial communications system. Generally speaking, the terrestrial communications system is developed in a short period. Especially, the recent network related IT technology changes very rapidly, like so-called as "Dog Year". On the other hand, it takes a long time, more than several years, to develop a satellite communications system. This paper will discuss this time period of development is how to influence the system realization in various cases. In the second, the service related cost is discussed. First, a mobile communications satellite system is considered as an example. The tremendous penetration speed of the terrestrial cellular phones prevents from the success of the mobile satellite communications system. The success of the mobile satellite communications system depends on how early and user friendly to develop its user terminals. Second, the broadcasting service is described as a successful example. It is described that the satellite broadcasting has a very competitive advantage to the terrestrial broadcasting service from the cost point of view. Finally, the cost of the technology R&D for the future communication satellite by the government is discussed. A model of the future communications satellite for next 30 years has been proposed(1)(2). As an example, this paper estimates the satellite cost of the 60 Gbps range of capacity which is called as 1.5G satellite, where the capacity of the second generation Internet satellite (2G) is 50-500 Gbps per satellite. In the paper, the R&D plan of the future communications satellite will be discussed as a next R&D project to the first generation Internet satellite from a cost point of view. References (1)T.Iida and Y.Suzuki: "Satellite Communications R&D for Next 30 Years", 19th AIAA (2)T.Iida, Y.Suzuki and A.Akaishi: "Satellite Communications R&D for Next 30 Years:

Iida, Takashi

2002-01-01

248

Space Weather Effects on Communications An overview of historical and contemporary impacts of the solar and geospace  

E-print Network

Space Weather Effects on Communications An overview of historical and contemporary impacts-Line Telegraph Communications The effects of the solar-terrestrial environment on communications technologies of the solar and geospace environments on communications systems. Louis J. Lanzerotti Center for Solar

249

Terrestrial versus giant planet formation  

NASA Technical Reports Server (NTRS)

Given a solar nebular surrounding the early protosun, containing dust grains that have already undergone growth through collisions to about centimeter-size, the question of the formation of the terrestrial and giant planets is considered. In contrast to the usual approach of emphasizing how well a problem is understood, the uncertainties and areas where more work needs to be done will be accentuated. Also, the emphasis will be on the dynamics of planetary formation, because profound problems still exist in this area, and because it seems most logical to concentrate first on the dynamical questions involved with assembling the planets before putting too much effort into the detailed chemical and geological consequences of certain formation mechanisms.

Boss, Alan P.

1988-01-01

250

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 PMID:8202505

Hackstein, J H; Stumm, C K

1994-01-01

251

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

252

Phytopharmacological overview of Tribulus terrestris  

PubMed Central

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

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

2014-01-01

253

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

254

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

255

Solar Terrestrial Relations Observatory (STEREO)  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

256

Insignificant solar-terrestrial triggering of earthquakes  

USGS Publications Warehouse

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

Love, Jeffrey J.; Thomas, Jeremy N.

2013-01-01

257

Digital terrestrial television for Malaysia  

Microsoft Academic Search

Television is one of the most powerful components of information communication technology. It has the power to influence the public as well as educate and entertain them. As such, a lot of development in television engineering has taken place. Television has changed from black\\/white to colour. However, the international community could not accept a single colour TV standard and 3

V. Jeewa

2003-01-01

258

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

259

Long-term solar-terrestrial observations  

NASA Astrophysics Data System (ADS)

In the fall of 1985, the Committee on Solar-Terrestrial Research (CSTR) created a panel to study the requirements for long-term monitoring and archiving of solar-terrestrial data. The panel comprised specialists in all four areas that constitute solar-terrestrial science: the sun, interplanetary medium, magnetosphere-thermosphere-ionosphere, and upper atmosphere. It interviewed many individuals from the solar-terrestrial monitoring and data archiving communities, along with administrators and directors from appropriate government agencies. It circulated nearly 500 questionnaires to obtain information and opinions from the broader community to learn which observational data should be considered essential over the long term to support the operational and research needs of solar-terrestrial science. This report summarizes the panel's principal findings, and the panel's recommendations follow. A separate section listing the critical observational needs by area is presented together with the scientific rationale for each area. The recommendations are defended in terms of this explicit scientific rationale and the multifold uses of current and long-term solar-terrestrial observations for continued operational solar-terrestrial forecasts and services.

260

The evolution of global mobile communications  

NASA Astrophysics Data System (ADS)

A long term, global viewpoint is presented on the subject of communications access which may be the key to resolving many of the world's current requirements for developing a truly global, ubiquitous mobile/personal voice and data communications capability. The solutions are multi disciplinary, some using terrestrial techniques, some by satellite, but both using a variety of technologies and techniques. In the area of satellite communications, the focus is on inexpensive, efficient antennas, high gain spacecraft amplifiers and efficient power and bandwidth modulation techniques including high performance, low bit rate voice codecs. Terrestrially, many of the same technologies apply to cellular telephone systems. A key issue is the electromagnetic spectrum and its utilization efficiency, especially if the popularity of cellular telephones is repeated in the development of mobile satellite systems. Integration of diverse systems depends on formulating a framework that will allow systems to be interoperable by specifying logical interfaces among most or all evolving niche systems.

Spolsky, A. I.; Brasic, J. R.

261

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

262

Chemical Communication  

NSDL National Science Digital Library

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

0002-11-30

263

Information communication  

E-print Network

Codes November 22, 2006 Erasure Channels 1 . In many practical communication systems, information, HDTV and in communication with Voyager, Galileo and other space satellites. Luby Transform (LT) Codes 5

Roweis, Sam

264

Transmission communication  

E-print Network

communication system . MODEM functions . Channel has finite bandwidth and introduces noise: two main factors communication, this lecture we will again go through pulse shaping and Tx/Rx filter pair, but in more depth

Chen, Sheng

265

Transactions COMMUNICATION  

E-print Network

Dalton Transactions COMMUNICATION Cite this: Dalton Trans., 2013, 42, 879 Received 19th July 2012 In this communication, we report the synthesis, characterization, and electrochemistry of a 2-(2-hydroxyphenyl)-1H

Govindjee

266

fundamental communication  

E-print Network

of communication is that of reproducing at one point either exactly or approximately a message selected at another of communication'' founded the field of information theory. It contained two theorems that we will discuss

Shor, Peter W.

267

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

268

Data communications  

SciTech Connect

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

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

1993-08-01

269

College of Communication and Information COM Communication  

E-print Network

.Itisalsodesignedtoimprovecommunicationskillswithandamong physicians, nurses, and allied health professionals. COM 312 LEARNING INTERCULTURAL COMMUNICATION THROUGHCollege of Communication and Information COM Communication KEY: # = new course * = course changed TO COMMUNICATIONS. (3) Anintroductiontotheprocessofcommunicationasacriticalelementinhumaninteractionandinsociety

MacAdam, Keith

270

Terrestrial Mobile Mapping: photogrammetric simulator  

NASA Astrophysics Data System (ADS)

Nowadays many types of sensors are used for terrestrial mobile mapping (TMM): IMU, odometers, GNSS, cameras, etc., and it is essential to understand how these sensors can improve the solution in terms of precision, accuracy and reliability. TMM issues are characterized by many variables: vehicle trajectory, the height of the buildings and the distance between them, traffic conditions, the presence or absence of trees, the level of illumination, etc. The aim of this study is to determine how photogrammetric measurements can improve the quality of TMM solution at least concerning magnitude and error propagation when there is no GNSS signal (for example in an urban canyon). Another purpose of the study was to determine the most suitable design project for a specific relief in order to obtain the best possible photogrammetric results. By analyzing the error propagation in the various components of relative orientation along the trajectory and considering a sequence of images characterized by an overlap varying between 60 to 90% and the same number of tie points, results were obtained which confirmed the reliability of the data produced by the simulator. These results are shown in this paper.

Taglioretti, C.; Manzino, A. M.

2014-08-01

271

Terrestrial cooling and solar variability  

NASA Technical Reports Server (NTRS)

Observational evidence from surface temperature records is presented and discussed which suggests a significant cooling trend over the Northern Hemisphere from 1940 to the present. This cooling trend is associated with an increase of the latitudinal gradient of temperature and the lapse rate, as predicted by climate models with decreased solar input and feedback mechanisms. Evidence suggests that four of these 80- to 100-year cycles of global surface temperature fluctuation may have occurred, and in succession, from 1600 to the present. Interpretation of sunspot activity were used to infer a direct thermal response of terrestrial temperature to solar variability on the time scale of the Gleissberg cycle (90 years, an amplitude of the 11-year cycles). A physical link between the sunspot activity and the solar parameter is hypothesized. Observations of sensible heat flux by stationary planetary waves and transient eddies, as well as general circulation modeling results of these processes, were examined from the viewpoint of the hypothesis of cooling due to reduced insolation.

Agee, E. M.

1982-01-01

272

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

273

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

274

Steroidal saponins from Tribulus terrestris.  

PubMed

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

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

2014-11-01

275

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

276

Communication Prsentation  

E-print Network

Communication et mobilité version du 2 janvier 2003 -- 20 : 07 #12; 1 Présentation du problème (lambda­calcul) Un des problèmes clés aujourd'hui est celui de la communication et de la mobilité. Cours de sémantique --- automne 2002 #12; 3 Communication Il faut décrire les communications. #### #### d

Lescanne, Pierre

277

Communication, Communication, Communication! Growth through Laboratory Instructing  

ERIC Educational Resources Information Center

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

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

2014-01-01

278

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

279

Communication Telecommunications  

E-print Network

A Random Matrix Model of Communication Through Antenna Arrays Ralf R. M uller Vienna Research receiver channel transmitter R. M uller: A Random Matrix Model of Communication Through Antenna Arrays c Matrix Model of Communication Through Antenna Arrays c ftw. 2000 #12; I. Channel Model 4 Proposed Model

Müller, Ralf R.

280

Communication Performance  

E-print Network

A Random Matrix Model for Communication via Antenna Arrays Ralf R. M uller 1. Motivation 2 of Low{Complexity Receivers #12; I. Motivation 2 Information Theory of Communications encoder decoder for Communication via Antenna Arrays c ftw. 2001 #12; I. Motivation 3 Shannon vs. Moore time #15; bandwidth

Müller, Ralf R.

281

transmitted, communication  

E-print Network

basic issues: Part I How data frames can be reliably transmitted, and Part II How a shared communication medium can be accessed . In many networks, such as an LAN, communication medium is shared. So you first communication channel can be accessed, and how a data frame can be reliably transmitted -- Network: describes

Chen, Sheng

282

fundamental communication  

E-print Network

of all networks, and we will first revisit some of fundamental limits imposed on communication media a brief review of a variety of transmission media . Communication networks can be classified as switched, for physically realisable, a communication system need some extra bandwidth specified typically by a roll

Chen, Sheng

283

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

SciTech Connect

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 digestive glands. These responses are able to provide accurate indications of sublethal toxicity. Toxicity tests with terrestrial isopods could be much more reliable through the use of positive controls. A positive control with a reference toxicant could also be supplemented by a reference endpoint. The most suitable reference endpoint is change of food consumption rate. Toxicity testing with terrestrial isopods is a very promising method for fast, routine, and inexpensive laboratory determination of the relative toxicities of chemicals in the terrestrial environment.

Drobne, D. [Univ. of Ljubljana (Slovenia). Dept. of Biology

1997-06-01

284

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

285

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

286

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...

287

Terrestrial passage theory of the moon illusion.  

PubMed

Theories of the celestial, or moon, illusion have neglected geometric characteristics of movement along and above the surface of the earth. The illusion occurs because the characteristics of terrestrial passage are attributed to celestial passage. In terrestrial passage, the visual angle subtended by an object changes discriminably as an essentially invariant function of elevation above the horizon. In celestial passage, by contrast, change in visual angle is indiscriminable at all elevations. If a terrestrial object gains altitude, its angular subtense fails to follow the expansion projected for an orbital course: Angular diminution or constancy is equivalent to distancing. On the basis of terrestrial projections, a similar failure of celestial objects in successive elevations is also equivalent to distancing. The illusion occurs because of retinal image constancy, not--as traditionally stated--despite it. PMID:6240520

Reed, C F

1984-12-01

288

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

289

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...

290

Update on terrestrial ages of Antarctic meteorites  

NASA Astrophysics Data System (ADS)

Cosmic-ray produced Cl-36 (half-life = 3.01 x 10 to the 5th years) has been measured in 90 Antarctic meteorites by accelerator mass spectrometry. The terrestrial ages of the meteorites were calculated from the results. After excluding possible paired objects, 138 terrestrial ages from 18 different locations are available from C-14, Kr-81, and Cl-36 measurements for application to Antarctic meteorite and glaciological studies. The terrestrial ages of Allan Hills meteorites vary from 2000 years to 1 million years and are clearly longer than those of Yamato meteorites and other Antarctic meteorites. The oldest Allan Hills meteorites were found close to the eastern edge and in the southeast of the main icefield. Among all Antarctic meteorites measured to date, only L and LL chondrites have terrestrial ages older than 370,000 years.

Nishiizumi, K.; Elmore, D.; Kubik, P. W.

1989-07-01

291

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

292

High Efficiency, Long Life Terrestrial Solar Panel.  

National Technical Information Service (NTIS)

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 evalua...

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

1977-01-01

293

Parallel Computing for Terrestrial Ecosystem Carbon Modeling  

SciTech Connect

Terrestrial ecosystems are a primary component of research on global environmental change. Observational and modeling research on terrestrial ecosystems at the global scale, however, has lagged behind their counterparts for oceanic and atmospheric systems, largely because the unique challenges associated with the tremendous diversity and complexity of terrestrial ecosystems. There are 8 major types of terrestrial ecosystem: tropical rain forest, savannas, deserts, temperate grassland, deciduous forest, coniferous forest, tundra, and chaparral. The carbon cycle is an important mechanism in the coupling of terrestrial ecosystems with climate through biological fluxes of CO{sub 2}. The influence of terrestrial ecosystems on atmospheric CO{sub 2} can be modeled via several means at different timescales. Important processes include plant dynamics, change in land use, as well as ecosystem biogeography. Over the past several decades, many terrestrial ecosystem models (see the 'Model developments' section) have been developed to understand the interactions between terrestrial carbon storage and CO{sub 2} concentration in the atmosphere, as well as the consequences of these interactions. Early TECMs generally adapted simple box-flow exchange models, in which photosynthetic CO{sub 2} uptake and respiratory CO{sub 2} release are simulated in an empirical manner with a small number of vegetation and soil carbon pools. Demands on kinds and amount of information required from global TECMs have grown. Recently, along with the rapid development of parallel computing, spatially explicit TECMs with detailed process based representations of carbon dynamics become attractive, because those models can readily incorporate a variety of additional ecosystem processes (such as dispersal, establishment, growth, mortality etc.) and environmental factors (such as landscape position, pest populations, disturbances, resource manipulations, etc.), and provide information to frame policy options for climate change impact analysis.

Wang, Dali [ORNL; Post, Wilfred M [ORNL; Ricciuto, Daniel M [ORNL; Berry, Michael [University of Tennessee, Knoxville (UTK)

2011-01-01

294

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

295

Architectures and protocols for an integrated satellite-terrestrial mobile system  

NASA Technical Reports Server (NTRS)

This paper aims to depict some basic concepts related to the definition of an integrated system for mobile communications, consisting of a satellite network and a terrestrial cellular network. In particular three aspects are discussed: (1) architecture definition for the satellite network; (2) assignment strategy of the satellite channels; and (3) definition of 'internetworking procedures' between cellular and satellite network, according to the selected architecture and the satellite channel assignment strategy.

Delre, E.; Dellipriscoli, F.; Iannucci, P.; Menolascino, R.; Settimo, F.

1993-01-01

296

Early Formation of Terrestrial Crust  

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

297

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

298

MODIS-Derived Terrestrial Primary Production  

NASA Astrophysics Data System (ADS)

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

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

299

Performance simulation in high altitude platforms (HAPs) communications systems  

NASA Astrophysics Data System (ADS)

This paper considers the analysis by simulation of a digital narrowband communication system for an scenario which consists of a High-Altitude aeronautical Platform (HAP) and fixed/mobile terrestrial transceivers. The aeronautical channel is modelled considering geometrical (angle of elevation vs. horizontal distance of the terrestrial reflectors) and statistical arguments and under these circumstances a serial concatenated coded digital transmission is analysed for several hypothesis related to radio-electric coverage areas. The results indicate a good feasibility for the communication system proposed and analysed.

Ulloa-Vásquez, Fernando; Delgado-Penin, J. A.

2002-07-01

300

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

301

Troposphere communications  

NASA Astrophysics Data System (ADS)

The physical processes and features of troposphere radiowave propagation are reviewed, and fundamental principles for the construction of troposphere lines of communication are discussed. The technical characteristics of troposphere stations in the USA, England, France, FRG, and Japan are studied and compared. Attention is given to mobile and stationary military stations, and to stationary troposphere communication systems in the Americas, Greenland, the Caribbean islands, Asia, Africa, and Australia. Developments in troposphere communications, including the AN/TRC-170 station, are discussed.

Iakovlev, L. I.; Dediukin, G. V.; Kagramanov, E. S.; Redin, A. P.; Stuton, P. I.; Tsybulkin, L. D.

302

Terrestrial plasma source - a new perspective in solar-terrestrial processes from Dynamics Explorer  

Microsoft Academic Search

The geospace environment has been viewed as a mixing bowl for plasmas of both solar and terrestrial origin. The present perspective on the nature of the supply mechanisms has undergone a radical evolution over the past decade, particularly during the five years of the Dynamics Explorer mission. During this period, the terrestrial source has increased in importance in both magnitude

Charles R. Chappell

1988-01-01

303

The terrestrial plasma source - A new perspective in solar-terrestrial processes from Dynamics Explorer  

Microsoft Academic Search

The geospace environment has been viewed as a mixing bowl for plasmas of both solar and terrestrial origin. The present perspective on the nature of the supply mechanisms has undergone a radical evolution over the past decade, particularly during the five years of the Dynamics Explorer mission. During this period, the terrestrial source has increased in importance in both magnitude

Charles R. Chappell

1988-01-01

304

The terrestrial plasma source: A new perspective in solar-terrestrial processes from Dynamics Explorer  

Microsoft Academic Search

The geospace environment has been viewed as a mixing bowl for plasmas of both solar and terrestrial origin. Our perspective on the nature of the supply mechanisms has undergone a radical evolution over the past decade, particularly during the 5 years of the Dynamics Explorer mission. During this period, the terrestrial source has increased in importance in both magnitude and

Charles R. Chappell

1988-01-01

305

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

306

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

307

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

308

Hyperspectral-LIDAR system and data product integration for terrestrial applications  

NASA Astrophysics Data System (ADS)

This manuscript details the development and validation of a unique forward thinking instrument and methodology for monitoring terrestrial carbon dynamics through synthesis of existing hyperspectal sensing and Light Detection and Ranging (LIDAR) technologies. This technology demonstration is directly applicable to linking target mission concepts identified as scientific priorities in the National Research Council (NRC, 2007) Earth Science Decadal Survey; namely, DESDynI and HyspIRI. The primary components of the Hyperspec-LIDAR system are the ruggedized imaging spectrometer and a small footprint LIDAR system. The system is mounted on a heavy duty motorized pan-tilt unit programmed to support both push-broom style hyperspectral imaging and 3-D canopy LIDAR structural profiling. The integrated Hyperspec-LIDAR sensor system yields a hypserspectral data cube with up to 800 bands covering the spectral range of 400 to 1000 nm and a 3-D scanning LIDAR system accurately measuring the vertical distribution of intercepted surfaces within a range of 150 m with an accuracy of 15 mm. Preliminary field tests of the Hyperspec-LIDAR sensor system were conducted at a mature deciduous mixed forest tower site located at the Smithsonian Environmental Research Center in Edgewater, MD. The goal of this research is to produce integrated science and data products from ground observations that will support satellite-based hybrid spectral/structural profile linked through appropriate models to monitor Net Ecosystem Exchange and related parameters such as ecosystem Light Use Efficiency.

Corp, Lawrence A.; Cheng, Yen-Ben; Middleton, Elizabeth M.; Parker, Geoffrey G.; Huemmrich, K. Fred; Campbell, Petya K. E.

2009-08-01

309

Odyssey personal communications satellite system  

NASA Technical Reports Server (NTRS)

The spectacular growth of cellular telephone networks has proved the demand for personal communications. Large regions of the world are too sparsely populated to be economically served by terrestrial cellular communications. Since satellites are well suited to this application, TRW filed with the FCC on May 31, 1993 for the Odyssey construction permit. Odyssey will provide high quality wireless communication services worldwide from satellites. These services will include: voice, data, paging, and messaging. Odyssey will be an economical approach to providing communications. A constellation of 12 satellites will be orbited in three, 55 deg. inclined planes at an altitude of 10,354 km to provide continuous coverage of designated regions. Two satellites will be visible anywhere in the world at all times. This dual visibility leads to high line-of-sight elevation angles, minimizing obstructions by terrain, trees and buildings. Each satellite generates a multibeam antenna pattern that divides its coverage area into a set of contiguous cells. The communications system employs spread spectrum CDMA on both the uplinks and downlinks. This signaling method permits band sharing with other systems and applications. Signal processing is accomplished on the ground at the satellite's 'Gateway' stations. The 'bent pipe' transponders accommodates different regional standards, as well as signaling changes over time. The low power Odyssey handset will be cellular compatible. Multipath fade protection is provided in the handset.

Spitzer, Christopher J.

1993-01-01

310

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

311

The ORBCOMM data communications system  

NASA Astrophysics Data System (ADS)

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.

312

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

313

Multimodal communication  

NASA Astrophysics Data System (ADS)

Communication is understood in the entire domain of a humans' input output facilities. The idea of language consisting of a combination of audio, visual, and other modalities in perception and being produced with a combination of vocal, hand, and other physical gestures is explored. Issues of feedback, control and definition of language structures are considered. It is hypothesized that the multi modal communication inside virtual spaces will augment and/or replace former communication forms. A rough prototype system is presented for communication between individuals in multiple modalities. The prototype system consists of glove monitored gesture input and graphics workstations along with auditory communication. While two people talk they add meaning on the visual display with images and movement. Applications and future development of multimodal communication is discussed based on technology currently available. The ultimate communications channel would allow for all the transmitters neural patterns (not just vocal, face and hand motion) to be mapped onto all the receivers sensory neurons (sight, touch, hearing, smell, etc.) Multimodal high bandwidth information transfer will facilitate all communication within our civilization through higher accuracy, greater speed, and deepened meaning.

Tolman, Kenneth.

1993-01-01

314

interprocess communication  

E-print Network

�process communication . int pipe(int filedes[2]); . Linux: pipe creates a pair of file descriptors, pointing to a pipe.17 19 Client�Server Communication Using FIFOs . Writes of up to PIPE_BUF bytes are atomic � one FIFO can

Carette, Jacques

315

Communication of \\  

Microsoft Academic Search

Risk management depends on effective communication not only among societal domains such as authorities, experts, and the public, but also among members of any one domain. Using the example of flood management, this paper examines risk-related tasks of experts showing the collaborative nature of risk management. A review of risk communication considers modes for interaction, representation with respect to documentation,

Charlotte Kaempf

2004-01-01

316

Communications spacecraft  

Microsoft Academic Search

Progress in the designs and performance capabilities of communications satellites is traced from the Echo 1 Al-coated mylar balloon in 1960 to systems planned for the 1990s and beyond. The services allowed with the passive balloon concept were too limited and led to Telstar spacecraft, with 600 voice channels, being placed in elliptical orbits. Geosynchronous communications began in 1963 with

Samuel W. Fordyce

1986-01-01

317

Communications Technology.  

ERIC Educational Resources Information Center

This paper describes types of interactive communications technologies relevant to education and discusses their current and potential uses in rural Australia. "Teleconferencing" is a generic term for interactive electronic communications. The four main types of teleconferencing--audio, audiographic, video, and computer (text)…

Lundin, Roy

318

A Possible Aeronomy of Extrasolar Terrestrial Planets  

E-print Network

Terrestrial planetary systems may exist around nearby stars as the Earth-sized counterparts to the many giant planets already discovered within the solar neighborhood. In this chapter we first discuss the numerous techniques which have been suggested to search for extrasolar terrestrial planets. We then focus on the expected results from that technique in which an orbiting telescope or interferometer is used to obtain a visible or infrared spectrum of a planet, without contamination from the parent star. We show examples of such spectra for selected cases: the present Earth, the Neoproterozoic (snowball) Earth, a methane-rich Earth, and the present Mars and Venus. We conclude by discussing the implications of such spectra for the detection of life on an extrasolar terrestrial planet.

W. A. Traub; K. W. Jucks

2002-05-22

319

A Possible Aeronomy of Extrasolar Terrestrial Planets  

E-print Network

Terrestrial planetary systems may exist around nearby stars as the Earth-sized counterparts to the many giant planets already discovered within the solar neighborhood. In this chapter we first discuss the numerous techniques which have been suggested to search for extrasolar terrestrial planets. We then focus on the expected results from that technique in which an orbiting telescope or interferometer is used to obtain a visible or infrared spectrum of a planet, without contamination from the parent star. We show examples of such spectra for selected cases: the present Earth, the Neoproterozoic (snowball) Earth, a methane-rich Earth, and the present Mars and Venus. We conclude by discussing the implications of such spectra for the detection of life on an extrasolar terrestrial planet.

Traub, W A

2002-01-01

320

Communications spacecraft  

NASA Astrophysics Data System (ADS)

Progress in the designs and performance capabilities of communications satellites is traced from the Echo 1 Al-coated mylar balloon in 1960 to systems planned for the 1990s and beyond. The services allowed with the passive balloon concept were too limited and led to Telstar spacecraft, with 600 voice channels, being placed in elliptical orbits. Geosynchronous communications began in 1963 with the Syncom satellite, which also carried television signals. The evolution of subsequent Intelsat and ANIK satellites is described, as are features of the Marisat, Marecs, and the DBS systems. The near-term capabilities for DBS, advanced communications satellites using TDMA techniques, and mobile communications systems are summarized, along with the NASA ACTS and MSAT-X satellites for exploring the necessary technologies. The roles the Space Station and unmanned GEO platforms will play in future satellite communications are discussed.

Fordyce, Samuel W.

321

Responses of terrestrial aridity to global warming  

NASA Astrophysics Data System (ADS)

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

Fu, Qiang; Feng, Song

2014-07-01

322

Communicating health.  

PubMed

Routine production of communication materials without paying attention to utilization, field test, and impact analysis is ineffective. The concept of information, education, and communication (IEC) should encompass voluntary activity of health education in a tradition of innovation. One seminal factor may be the communication technologies developed by the National Technology Missions. The missions were participatory by seeking solutions among communities and analyzing health issues from the perspective of those directly involved, rather than from the top down. The prime focus of the national drinking water mission was convenience, hence messages concentrating on health advantages were ignored. At this juncture, influencing health behavior required decentralization reflecting local cultures. Thus community-based partners became the foundation of a strategy of communicating safe water. As national strategies emerged in each of the technology missions, communication addressed advocacy of the need for political will, dissemination of technical information, and influencing patterns of behavior. Despite learning a new understanding, the danger exists that IEC remains just another label of mass communication with posters, advertisements, brochures, radio, and television. Decisions on contraceptive choice and use requires more than just accurate information; it requires the power to make such a decision. A new approach demands a priority for communication skills taking into account people's aspirations. The HIV-AIDS crisis underlines the urgency with which communication has to respond to health challenges. A series of experiments facilitated by the World Conservation Union helped build communication capabilities among environmental groups working in Latin America, Africa, and India. The International Reference Center on Water and Sanitation initiated pilot communication projects in West Africa for community health. PMID:12290698

Chatterjee, A

1995-01-01

323

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

324

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

325

The development of early terrestrial ecosystems  

E-print Network

of subaerial diagenesis in the 1.2-b.y. Mescal Limestone, central Arizona: implications for the timing and development of a terrestrial plant cover. Geological Society of America, Bulletin 96,737-745. THE DEVELOPMENT OF EARLY TERRESTRIAL ECOSYSTEMS 355 Bell..., P.R. (1989). 'Heterospory' in Sphagnum: fifty years of error. Journal of Bryology 15, 679-682. Berkner, L.V. & Marshall, L.C. (1965). On the origin and rise of oxygen concentration in the Earth's atmosphere. Journal of Atmospheric Science 22...

Selden, Paul A.; Edwards, Dianne

1993-01-01

326

Monogenetic volcanoes of the terrestrial planets  

NASA Technical Reports Server (NTRS)

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 m/sec, only 1/3 to 1/10 as high as for equal volume terrestrial eruptions. These low velocities imply low volatile contents for both Martian and lunar magmas.

Wood, C. A.

1979-01-01

327

Terrestrial Planet Finder Coronagraph Observatory summary  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

328

Communication architecture of an early warning system  

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

329

Science communication as political communication.  

PubMed

Scientific debates in modern societies often blur the lines between the science that is being debated and the political, moral, and legal implications that come with its societal applications. This manuscript traces the origins of this phenomenon to professional norms within the scientific discipline and to the nature and complexities of modern science and offers an expanded model of science communication that takes into account the political contexts in which science communication takes place. In a second step, it explores what we know from empirical work in political communication, public opinion research, and communication research about the dynamics that determine how issues are debated and attitudes are formed in political environments. Finally, it discusses how and why it will be increasingly important for science communicators to draw from these different literatures to ensure that the voice of the scientific community is heard in the broader societal debates surrounding science. PMID:25225389

Scheufele, Dietram A

2014-09-16

330

Science communication as political communication  

PubMed Central

Scientific debates in modern societies often blur the lines between the science that is being debated and the political, moral, and legal implications that come with its societal applications. This manuscript traces the origins of this phenomenon to professional norms within the scientific discipline and to the nature and complexities of modern science and offers an expanded model of science communication that takes into account the political contexts in which science communication takes place. In a second step, it explores what we know from empirical work in political communication, public opinion research, and communication research about the dynamics that determine how issues are debated and attitudes are formed in political environments. Finally, it discusses how and why it will be increasingly important for science communicators to draw from these different literatures to ensure that the voice of the scientific community is heard in the broader societal debates surrounding science. PMID:25225389

Scheufele, Dietram A.

2014-01-01

331

A Model-Data Framework for Linking Satellite-Based Data on Vegetation Structure with a Height Structured Ecosystem Model Over North America  

NASA Astrophysics Data System (ADS)

One of the most challenging aspects of ecosystem modeling is to account for the dynamic mosaic of patches on the landscape that result from the processes of disturbance and recovery. In the absence of such information, model stocks and fluxes will vary greatly depending on the prescribed successional state, often assumed to be “potential”. Although great efforts have been made to derive model initial conditions from passive optical remote sensing, many optical metrics, especially those related to LAI, saturate much earlier in succession than do biomass and other structure, such as height. Recent studies have addressed this heterogeneity by combining remotely sensed measurements of vegetation structure, and advanced ecological models that track the dynamics of vegetation structure, to produce accurate estimates of both carbon stocks and fluxes at a set of important study sites. Theoretical studies have demonstrated that a robust model-data framework will require both models and data on vegetation structure sufficient to resolve important environmental gradients and tree-level heterogeneity in forest structure globally. Here, we present a model-data framework for linking satellite-based data on vegetation structure with a height-structured ecosystem model over North America. The core of the framework links GLAS data on vegetation structure and other data sources with the height structured Ecosystem Demography (ED) model. The framework is used to improve model predictions of carbon stocks and fluxes, quantify uncertainties, and prepare for future space-based missions on vegetation structure.

Hurtt, G. C.; Dubayah, R.; Fisk, J.; Moorcroft, P. R.; Lefsky, M. A.

2009-12-01

332

On the ionospheric impact of recent storm events on satellite-based augmentation systems in middle and low-latitude sectors  

NASA Technical Reports Server (NTRS)

The Ionospheric correction algorithms have been characterized extensively for the mid-latitude region of the ionosphere where benign conditions usually exist. The United States Federal Aviation Administration's (FAA) Wide Area Augmentation System (WAAS) for civil aircraft navigation is focused primarily on the Conterminous United States (CONUS). Other Satellite-based Augmentation Systems (SBAS) include the European Geostationary Navigation Overlay Service (EGNOS) and the Japanese Global Navigation Satellite System (MSAS). Researchers are facing a more serious challenge in addressing the ionospheric impact on navigation using SBAS in other parts of the world such as the South American region on India. At equatorial latitudes, geophysical conditions lead to the so-called Appleton-Hartree (equatorial) anomaly phenomenon, which results in significantly larger ionospheric range delays and range delay spatial gradients than is observed in the CONUS or European sectors. In this paper, we use GPS measurements of geomagnetic storm days to perform a quantitative assessment of WAAS-type ionospheric correction algorithms in other parts of the world such as the low-latitude Brazil and mid-latitude Europe. For the study, we access a world-wide network of 400+ dual frequency GPS receivers.

Komjathy, Attila; Sparks, Lawrence; Mannucci, Anthony J.; Pi, Xiaoqing

2003-01-01

333

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

334

Terrestrial Planet Formation in the ? Centauri System  

Microsoft Academic Search

We examine the late stages of terrestrial planet formation around each star in theCentauri A and ? Centauri B binary system. Each integration begins with a '' bimodal '' mass distribution of 14 large embryos embedded in a disk of smaller planetesimals orbiting one of the stars. These initial conditions were chosen because when they are used in simulations about

Elisa V. Quintana; Jack J. Lissauer; John E. Chambers; Martin J. Duncan

2002-01-01

335

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

336

Consumer strategies of terrestrial gastropods and isopods  

Microsoft Academic Search

Morphological, physiological and ecological evidence is used to show that terrestrial gastropods and isopods, although both can be considered as “primary consumers”, deal quite differently with the vegetabilic matter they use as food. Gastropods are both efficient digesters and assimilators whereas isopods are efficient digesters but usually inefficient assimilators. This combination may require the isopods to turn to coprophagy as

Wolfgang Wieser

1978-01-01

337

Extraterrestrial amino acids and terrestrial life  

NASA Astrophysics Data System (ADS)

Since the Swedish chemist Baron Jöns Jacob Berzelius first analysed the Alais meteorite for organic molecules' in 1834, attempts to forge a link between extraterrestrial organic materials and terrestrial life have remained alluring, but often deceptive. New studies reported in this and last week's issues hold the promise of important advances in both endeavours. (AIP)

Chyba, Christopher F.

1996-07-01

338

Moon and Terrestrial Planets: Unresolved Questions  

Microsoft Academic Search

Human exploration during Apollo began the documentation of the evolution of the Moon and of its importance in understanding the origin and evolution of the terrestrial planets. This revolution in planetary geology continues as a vigorous and vibrant arena for discovery and debate for new generations of geoscientists. Although much has been learned and, indeed, resolved in lunar science, we

H. H. Schmitt

2002-01-01

339

Oil Pollution in the Antarctic Terrestrial Environment  

Microsoft Academic Search

2 Abstract: Fuel oil has been extensively relied upon as an energy source since the earliest discovery and exploration of Antarctica. During this time oil spills have occurred, particularly around established research stations, which have had a negative impact on the terrestrial environment. Recently developed bioremediative technology, using indigenous Antarctic hydrocarbon-degrad- ing bacteria, may be used to assist in cleaning

Kevin A. Hughes; Bethan Stallwood

340

Hot oxygen coronas at terrestrial planets  

Microsoft Academic Search

Solar forcing via both influx of the solar wind plasma and absorption of ultraviolet radiation forms the hot oxygen coronas at the terrestrial planets (Shizgal and Arcos, 1996). These coronas were observed in the past and recent planetary space missions (Mariner, Pioneer Venus, IMAGE, Mars Express and etc.). We will dicsuss the relative role of the following energetic processes determining

V. I. Shematovich; R. E. Johnson

2006-01-01

341

A concept of digital terrestrial television broadcasting  

Microsoft Academic Search

The future terrestrial television broadcasting system should support the transmission of a digital HDTV signal with a high spectral efficiency. In addition, this system should maintain graceful degradation as the actual analog systems, and should be compatible with the SDTV. The system compatibility can be achieved by using a hierarchical HDTV source-coding scheme that can provide at least two (HDTV,

K. Fazel; S. Kaiser; P. Robertson; M. J. Ruf

1995-01-01

342

Spaceprobe images and the Terrestrial Planets Section  

Microsoft Academic Search

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

G. J. Day

1981-01-01

343

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

344

Thin film solar cells for terrestrial applications  

Microsoft Academic Search

A design has evolved from an earlier space cell which is promising for large scale terrestrial use. This is a front wall cell on zinc plated copper foil substrate with an evaporated grid and an integral glass cover formed by r.f. sputtering. This cell is suitable for low cost mass fabrication. Though it has not been fully proven it combines

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

1977-01-01

345

Subsolidus convective cooling histories of terrestrial planets  

Microsoft Academic Search

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

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

1979-01-01

346

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...

347

The geophysical signature of terrestrial impact craters  

Microsoft Academic Search

Terrestrial impact craters are examined in terms of their geophysical characteristics which can be used to identify additional impact craters. The geophysical signatures examined include the circular gravity low which is modeled for the cases of bowl-shaped and complex craters. The size of the gravity anomaly for both types of craters is established and modeled with known morphometric parameters of

M. Pilkington; R. A. F. Grieve

1992-01-01

348

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

349

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

350

Optical Communications  

ERIC Educational Resources Information Center

Describes the characteristics and operational problems of optical waveguides, and concludes that the wide use of optical communications can be expected if difficulties in commercial production of components can be eliminated. (CC)

Young, Matt

1973-01-01

351

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

NASA Astrophysics Data System (ADS)

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

1985-12-01

352

Police Communications  

NASA Technical Reports Server (NTRS)

Oklahoma City Police Department developed a computerized communications system, based on Johnson Space Center's (JSC's) 1960-mission control knowledge. JSC furnished information on lighting and other fatigue reducing measures, and provided specifications for equipment and design layouts. JSC also advised OCPD how to avoid communications bottlenecks associated with simultaneous handling of telephone, radio and inner-office transmissions. Oklahoma City saved money in reduced design and engineering costs by utilizing the already developed NASA technology.

1981-01-01

353

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

354

Engineering Communication  

NSDL National Science Digital Library

This engineering communication overview, created by Greg Heitkamp and published by the Engineering Technology Pathways project, gives students background in the "ability to express what is going on to different parts of a project" in engineering so that the project goes smoothly. A number of different approaches are discussed, including concurrent engineering and integrated product development (IPD), along with the benefits and disadvantages of each. This is a helpful introduction for engineering students to become acquainted with the communication fundamentals in the field.

Heitkamp, Greg

2010-10-07

355

Communicating Biosecurity  

Microsoft Academic Search

Shifting from risk-calculation orientations focusing on populations to preparedness perspectives that model uncertainty through scenario-based projections, biosecurity debates redefined notions of “health” and “security.” Nevertheless, a key focus of biosecurity discussions—the domain labeled “communication”—has not been fundamentally rethought, even as it has expanded and professionalized. Bracketing preconceived ideas about the term's content, the article traces debates about biosecurity “communication” from

Charles L. Briggs

2011-01-01

356

76 FR 50274 - Terrestrial Environmental Studies for Nuclear Power Stations  

Federal Register 2010, 2011, 2012, 2013

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

2011-08-12

357

77 FR 18271 - Terrestrial Environmental Studies for Nuclear Power Stations  

Federal Register 2010, 2011, 2012, 2013

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

2012-03-27

358

Center for Research on Enhancing Carbon Sequestration in Terrestrial Ecosystems  

E-print Network

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

359

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

360

Briefcase Communicator  

NASA Technical Reports Server (NTRS)

In the photo at bottom right, a U.S. Park Police officer is demonstrating a battery-powered communications system, sufficiently compact to be packed in a briefcase-size container, which can send and receive signals over great distances by means of satellite relay. Key to the system's efficacy is the high-powered transmitting and receiving equipment aboard such NASA satellites as the Applications Technology Satellite6 (ATS-6) and the joint U.S.-Canadian Communications Technology Satellite (CTS); this enables the briefcase communicator to pick up satellite-relayed signals by means of the small hook-on antenna shown instead of the more elaborate-ground equipment customarily needed. Developed by NASA's Goddard Space Flight Center, the communicator is intended for use in emergency situations. It has utility, for example, in disasters, such as floods and hurricanes, where power failure disrupts conventional communications; for on-the-spot transmissions from major accident sites; or in remote areas where no other means of communication exists

1979-01-01

361

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

362

Study of terrestrial ages of the Antarctic meteorites with thermoluminescence  

NASA Astrophysics Data System (ADS)

The terrestrial ages of Antarctic meteorites were estimated from the thermoluminescence (TL) intensity of the fusion crest. It was found that there is a good correlation between the TL intensities and terrestrial ages which were previously measured by cosmogenic-radionuclide abundance. It was also noticed that the LT/HT value gives false terrestrial ages. The basis for establishing the TL dating techniques regarding the terrestrial ages of Antarctic meteorites is presented.

Miono, S.; Nakanishi, A.

1993-04-01

363

Terrestrial Television Broadcasting in China: Technologies and Applications  

Microsoft Academic Search

\\u000a This chapter will discuss the two main terrestrial television broadcasting systems widely used in China. One is the China\\u000a Terrestrial Television Broadcasting (CTTB) standard which is named as “Frame structure, channel coding and modulation for\\u000a digital television terrestrial broadcasting system”. It was issued in August 2006 as a mandatory standard for traditional\\u000a terrestrial broadcasting and had been put into execution

Wenjun Zhang; Yunfeng Guan; Xiaokang Yang; Weiqiang Liang

2010-01-01

364

The optical communication link outage probability in satellite formation flying  

NASA Astrophysics Data System (ADS)

In recent years, several space systems consisting of multiple satellites flying in close formation have been proposed for various purposes such as interferometric synthetic aperture radar measurement (TerraSAR-X and the TanDEM-X), detecting extra-solar earth-like planets (Terrestrial Planet Finder-TPF and Darwin), and demonstrating distributed space systems (DARPA F6 project). Another important purpose, which is the concern of this paper, is for improving radio frequency communication to mobile terrestrial and maritime subscribers. In this case, radio frequency signals from several satellites coherently combine such that the received/transmit signal strength is increased proportionally with the number of satellites in the formation. This increase in signal strength allows to enhance the communication data rate and/or to reduce energy consumption and the antenna size of terrestrial mobile users' equipment. However, a coherent combination of signals without aligning the phases of the individual communication signals interrupts the communication and outage link between the satellites and the user. The accuracy of the phase estimation is a function of the inter-satellite laser ranging system performance. This paper derives an outage probability model of a coherent combination communication system as a function of the pointing vibration and jitter statistics of an inter-satellite laser ranging system tool. The coherent combination probability model, which could be used to improve the communication to mobile subscribers in air, sea and ground is the main importance of this work.

Arnon, Shlomi; Gill, Eberhard

2014-02-01

365

Spectrally Efficient CPM Waveforms for Narrowband Tactical Communications in Frequency Hopped Networks  

Microsoft Academic Search

A family of spectrally efficient waveforms for serial concatenated continuous phase modulation in frequency hopping systems is presented, for the challenging case where there are multiple hops per interleaver duration. The proposed waveforms are designed for narrowband tactical communication systems and are shown to meet stringent spectral emission masks of -40 dBc at the band edges for terrestrial communications below

C. BrownandP; P. J. Vigneron

2006-01-01

366

Development of stratospheric communication platforms (SCP) for rural applications  

Microsoft Academic Search

Despite advances in terrestrial telecommunications technology, almost three billion of the world's population living in rural locations is still without any telephone facilities. Apart from fixed and mobile satellite networks, new stratospheric communication platforms (SCPs) are the latest space techniques with advanced technology for fixed and all mobile applications, including military and rural solutions. These systems employ unmanned or manned,

S. D. Ilcev; A. Singh

2004-01-01

367

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

368

Wolbachia Bacteria Effects after Experimental Interspecific Transfers in Terrestrial Isopods  

E-print Network

Wolbachia Bacteria Effects after Experimental Interspecific Transfers in Terrestrial Isopods T of their hosts to increase in frequency in host populations. In terrestrial isopods for example, Wolba- chia in Bandi et al., 2001). In terrestrial isopods particularly, they are responsible for the feminization

369

Global response patterns of terrestrial plant species to nitrogen addition  

Microsoft Academic Search

Summary • Better understanding of the responses of terrestrial plant species under global nitrogen (N) enrichment is critical for projection of changes in structure, functioning, and service of terrestrial ecosystems.  Here, a meta-analysis of data from 304 studies was carried out to reveal the general response patterns of terrestrial plant species to the addition of N.  Across 456

Jianyang Xia; Shiqiang Wan

2008-01-01

370

Atmospheric Circulation of Terrestrial Exoplanets Adam P. Showman  

E-print Network

Atmospheric Circulation of Terrestrial Exoplanets Adam P. Showman University of Arizona Robin D 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

371

Terrestrial manganese-53 --A new monitor of Earth surface processes  

E-print Network

Terrestrial manganese-53 -- A new monitor of Earth surface processes Joerg M. Schaefer a,, Thomas of the terrestrial cosmogenic radionuclide manganese-53 (T1/2 =3.7 Ma) measured in thirteen samples from nine dolerite surfaces in the Dry Valleys, Antarctica. The terrestrial manganese-53 concentrations correlate

Winckler, Gisela

372

Terrestrial forest management plan for Palmyra Atoll  

USGS Publications Warehouse

This 'Terrestrial Forest Management Plan for Palmyra Atoll' was developed by the U.S. Geological Survey (USGS) for The Nature Conservancy (TNC) Palmyra Program to refine and expand goals and objectives developed through the Conservation Action Plan process. It is one in a series of adaptive management plans designed to achieve TNC's mission toward the protection and enhancement of native wildlife and habitat. The 'Terrestrial Forest Management Plan for Palmyra Atoll' focuses on ecosystem integrity and specifically identifies and addresses issues related to assessing the status and distribution of resources, as well as the pressures acting upon them, most specifically nonnative and potentially invasive species. The plan, which presents strategies for increasing ecosystem integrity, provides a framework to implement and track the progress of conservation and restoration goals related to terrestrial resources on Palmyra Atoll. The report in its present form is intended to be an overview of what is known about historical and current forest resources; it is not an exhaustive review of all available literature relevant to forest management but an attempt to assemble as much information specific to Palmyra Atoll as possible. Palmyra Atoll is one of the Northern Line Islands in the Pacific Ocean southwest of the Hawai`ian Islands. It consists of many heavily vegetated islets arranged in a horseshoe pattern around four lagoons and surrounded by a coral reef. The terrestrial ecosystem consists of three primary native vegetation types: Pisonia grandis forest, coastal strand forest, and grassland. Among these vegetation types, the health and extent of Pisonia grandis forest is of particular concern. Overall, the three vegetation types support 25 native plant species (two of which may be extirpated), 14 species of sea birds, six shore birds, at least one native reptile, at least seven native insects, and six native land crabs. Green and hawksbill turtles forage at Palmyra Atoll, and though rarely documented, beach nesting could be affected by terrestrial management actions. There are various nonnative or invasive species throughout the terrestrial ecosystem. The most notable examples of terrestrial invasive species include coconut palms (Cocos nucifera) and black rats (Rattus rattus). Although it is unclear whether they are nonnative, coconut palms are currently the most dominant plant across Palmyra Atoll. They compete with native plant species for space and resources and are potentially detrimental to sea birds dependent on native vegetation for roosting and nesting habitat. This competition in turn impacts nutrient resource availability, thereby reshaping energy flow in the ecosystem. Black rats are known to prey on ground-nesting sea birds and are likely responsible for the lack of burrowing sea bird reproduction at Palmyra Atoll. In addition, they may be facilitating the invasion of other nonnative species and negatively impacting other native fauna. Although the extent and impacts of these and other nonnative and (or) invasive species are not fully understood, the extent and impacts are clearly a threat to the native species and one of the most urgent threats to the overall ecosystem integrity of Palmyra Atoll. This 'Terrestrial Forest Management Plan for Palmyra Atoll' addresses issues related to invasive species and other problems. Priority goals are established as are associated objectives and strategies. The overarching goal is to perpetuate and where possible restore terrestrial ecosystem integrity through the following techniques: 1. Habitat management: Maintain and enhance habitat to the extent possible to sustain thriving Pisonia grandis forest, coastal strand forest, endemic grassland, self-sustaining populations of sea birds, shore birds, coconut crabs, native lizards, and native insects. 2. Monitoring and assessment: Acquire information on distribution and abundance as needed for conservation of each resour

Hathaway, Stacie A.; McEachern, Kathryn; Fisher, Robert N.

2011-01-01

373

Packet voice communication  

NASA Astrophysics Data System (ADS)

The problems of transmitting packetized voice signals are reviewed and the distortions resulting from digitization, speech detection, channel errors, and constant and stochastic transmission delays are analyzed. Measures to overcome distortions, and progress and goals in experimental networks which include satellite-based experiments are discussed.

Noll, Peter; Leesemann, Volker; Wessels, Guenter

1987-02-01

374

Digital Wireless Communication  

E-print Network

Digital Wireless Communication: Physical Layer Exploitation Wireless Networking and Communications Signals and Systems Digital Signal Processing Analog Communication Digital Communication Intro to Wireless;Why at the Graduate Level? It involves many different areas of expertise Digital communication

Heath Jr., - Robert W.

375

A satellite-based climatology (1989-2012) of lake surface water temperature from AVHRR 1-km for Central European water bodies  

NASA Astrophysics Data System (ADS)

The temperature of lakes is an important parameter for lake ecosystems influencing the speed of physio-chemical reactions, the concentration of dissolved gazes (e.g. oxygen), and vertical mixing. Even small temperature changes might have irreversible effects on the lacustrine system due to the high specific heat capacity of water. These effects could alter the quality of lake water depending on parameters like lake size and volume. Numerous studies mention lake water temperature as an indicator of climate change and in the Global Climate Observing System (GCOS) requirements it is listed as an essential climate variable. In contrast to in situ observations, satellite imagery offers the possibility to derive spatial patterns of lake surface water temperature (LSWT) and their variability. Moreover, although for some European lakes long in situ time series are available, the temperatures of many lakes are not measured or only on a non-regular basis making these observations insufficient for climate monitoring. However, only few satellite sensors offer the possibility to analyze time series which cover more than 20 years. The Advanced Very High Resolution Radiometer (AVHRR) is among these and has been flown on the National Oceanic and Atmospheric Administration (NOAA) Polar Operational Environmental Satellites (POES) and on the Meteorological Operational Satellites (MetOp) from the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) as a heritage instrument for almost 35 years. It will be carried on for at least ten more years finally offering a unique opportunity for satellite-based climate studies. Herein we present the results from a study initiated by the Swiss GCOS office to generate a satellite-based LSWT climatology for the pre-alpine water bodies in Switzerland. It relies on the extensive AVHRR 1-km data record (1985-2012) of the Remote Sensing Research Group at the University of Bern (RSGB) and has been derived from the AVHRR/2 (NOAA-11, -14) and AVHRR/3 (NOAA-16, -17, -18, -19 and Metop-A). A high accuracy is needed for climate related studies, which requires a careful pre-processing and consideration of the atmospheric state. Especially data from NOAA-16 and prior satellites were prone to unwanted noise, e.g., due to transmission errors or fluctuations in the instrument's thermal state. This has resulted in partly corrupted thermal calibration data and may cause errors of up to several Kelvin in the final brightness temperatures. Therefore, a multistage correction scheme has been applied to the data, in order to minimize these artefacts in the satellite observations. For the LSWT retrieval we have tested three different methods. First, we applied the operational NOAA National Environmental Satellite, Data, and Information Service (NESDIS) and NOAA Pathfinder global sea surface temperature (SST) algorithms to our data set. In addition, we developed an optimized simulation-based scheme making use of the Radiative Transfer for TOVS (RTTOV) Version 10 together with operational analysis and reanalysis data from the European Centre for Medium Range Weather Forecasts (ECMWF). All methods were validated extensively using in situ measurements from lakes with various sizes between 14 km2 (Lake Sempach) and 580 km2 (Lake Geneva). The simulation-based algorithm reduces the RMSE and Bias for the lakes in the study region of Switzerland compared to the global SST algorithms and even small lakes yield good results. Following these successful outcome, the model-based LSWT retrieval shall be expanded to all European lakes covered and recorded by the AVHRR data receiving station at the RSGB.

Riffler, Michael; Wunderle, Stefan

2013-04-01

376

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

377

Planetary System Evolution in the Terrestrial Zone  

NASA Astrophysics Data System (ADS)

We propose to characterize the role of major collisional episodes in the terrestrial zones of other planetary systems, using data from WISE (and Spitzer). We will: 1.) identify old stars whose terrestrial zones have recently been shaken up dynamically (e.g., activity similar to the Late Heavy Bombardment); and 2.) look for young stars where major collisions are occurring, signaling a phase analogous to the one when our Moon was formed. These two phases represent critical periods in the evolution of the Solar System. The Late Heavy Bombardment resulted from a destabilization of the Solar System by a mean-motion resonance between Jupiter and Saturn, leading to ejection of most of the planetesimals and an intense period of impacts onto the terrestrial planets. The formation of the Moon occurred in a younger violent phase, extending roughly from 30 to 130 Myr, when dynamical models predict that giant impacts will still occur even though most of the terrestrial planet formation is complete. Both of these phases would have produced copious dust in the terrestrial zone. Similar activity around other stars is detectable through the mid-infrared excesses emitted by such dust when it is warmed by the star (creating warm debris disks). However, previous infrared surveys have lacked the sensitivity, accuracy, or sky coverage to study this process systematically. For the first time, the WISE all-sky survey at 22 microns combines: 1.) a sufficiently large number of stars that these rare events should be seen in reasonable numbers; and 2.) mid-infrared photometry with sufficient accuracy to detect the excesses, even to within < 10% of the stellar photospheres. After extracting candidates from the WISE data, we will weed out false positives due to chance superpositions of sources or stellar mass loss. This will require acquiring ancillary data through a combination of information from the literature and new targeted observations using groundbased facilities. We will determine ages for the stars that survive this screening, using indicators such as chromospheric activity, spectral type (giant vs. main sequence), and position on a metallicity-adjusted HR diagram. The result will be a listing of stars with well-estimated ages and accurately- measured excesses signaling likely violent collisional episodes, providing a broad perspective on the frequency and intensity of the violent phases of planetary system evolution. We will put this work into context by comparison with the results of our theoretical models of debris disk collisional cascades and evolution. Our proposed work will allow comparison of critical events in the evolution of the Solar System and the Earth with the evolution of other planetary systems in their terrestrial zones.

Rieke, George

378

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

379

Mesoscale variability in time series data: Satellite-based estimates for the U.S. JGOFS Bermuda Atlantic Time-Series Study (BATS) site  

NASA Astrophysics Data System (ADS)

Objectively analyzed fields of satellite sea surface temperature (SST, advanced very high resolution radiometer (AVHRR) Pathfinder) and sea surface height anomaly (SSHA, combined TOPEX/Poseidon-ERS-1/2) are used to characterize, statistically, the mesoscale variability about the U.S. Joint Global Ocean Flux Study (JGOFS) Bermuda Atlantic Time-Series Study (BATS) site. These results are applied to the in situ BATS time series data and a local one-dimensional (1-D) physical upper ocean model to better understand the contribution of mesoscale eddies to the time series record and the model-data mismatch. Using a low-pass spatial filter, we decompose the anomalies from the seasonal cycle into two components: the large-scale, regional climate variability and a mesoscale signal. The mesoscale SST and SSHA fields are positively cross-correlated at a statistically significant level, consistent with near-surface isotherm displacements for cyclonic and anticyclonic eddies. The results from time-lagged cross-correlation analysis show that detectable eddy signatures exist in the in situ SST data and that eddies are a noticeable (~10%) but not dominant error source for the 1-D model solution. Several factors may be at work: the 1-D model captures a more regional signal, whereas the BATS in situ data include small-scale spatial heterogeneity; the satellite data and 1-D model are indirectly coupled via the National Centers for Environmental Prediction (NCEP) reanalysis forcing data; and the satellite-based mesoscale variability estimates are also missing specific events because of the sparse space-time sampling of a polar orbiting, visible/infrared wavelength sensor. The mesoscale eddy cross-correlation signature did not show up clearly in a similar analysis conducted on the original anomaly fields, highlighting the fact that climate scale variability needs to be carefully removed to isolate the eddy signature.

Glover, David M.; Doney, Scott C.; Mariano, Arthur J.; Evans, Robert H.; McCue, Scott J.

2002-08-01

380

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

381

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

E-print Network

and Convey 2007). However, terrestrial ecosystems of Antarctica are not immune to global changes (Adams et alEcological Biogeography of the Terrestrial Nematodes of Victoria Land, Antarctica 29 Ecological Biogeography of theTerrestrial Nematodes ofVictoria Land,Antarctica Byron J. Adams1 , Diana H. Wall2 , Ross A

Wall, Diana

382

Detection of Terrestrial Planets Using Transit Photometry  

NASA Technical Reports Server (NTRS)

Transit photometry detection of planets offers many advantages: an ability to detect terrestrial size planets, direct determination of the planet's size, applicability to all main-sequence stars, and a differential brightness change of the periodic signature being independent of stellar distance or planetary orbital semi-major axis. Ground and space based photometry have already been successful in detecting transits of the giant planet HD209458b. However, photometry 100 times better is required to detect terrestrial planets. We present results of laboratory measurements of an end-to-end photometric system incorporating all of the important confounding noise features of both the sky and a space based photometer including spacecraft jitter. In addition to demonstrating an instrumental noise of less than 10 ppm (an Earth transit of a solar-like star is 80 ppm), the brightnesses of individual stars were dimmed to simulate Earth-size transit signals. These 'transits' were reliably detected as part of the tests.

Koch, David; Witteborn, Fred; Jenkins, Jon; Dunham, Edward; Boruci, William; DeVincenzi, Donald (Technical Monitor)

2001-01-01

383

Terrestrial-passage theory: failing a test.  

PubMed

Terrestrial-passage theory proposes that the 'moon' and 'sky' illusions occur because observers learn to expect an elevation-dependent transformation of visual angle. The transformation accompanies daily movement through ordinary environments of fixed-altitude objects. Celestial objects display the same visual angle at all elevations, and hence are necessarily non-conforming with the ordinary transformation. On hypothesis, observers should target angular sizes to appear greater at elevation than at horizon. However, in a sample of forty-eight observers there was no significant difference between the perceived angular size of a constellation of stars at horizon and that predicted for a specific elevation. Occurrence of the illusion was not restricted to those observers who expected angular expansion. These findings fail to support the terrestrial-passage theory of the illusion. PMID:19662949

Reed, Charles F; Krupinski, Elizabeth A

2009-01-01

384

The precambrian evolution of terrestrial life.  

NASA Astrophysics Data System (ADS)

The early appearance of life on Earth suggests that under appropriate environmental conditions the probability of chemical evolution proceeding to the point of biogenesis may be reasonably high. Most of biological history has been the history of microorganisms, with tissue-grade plants and animals characterizing only the most recent 15% or so of the fossil record. Intelligent life has occupied only the latest instant in geological time. The time table of terrestrial evolution is governed more by the particulars of our planet's physical and biological history than by some universal tempo of evolutionary change. One aspect of terrestrial life that is likely to be universal is the organization of populations into efficient biogeochemical systems.

Knoll, A. H.

385

Solar Terrestrial Observatory Space Station Workshop Report  

NASA Technical Reports Server (NTRS)

In response to a need to develop and document requirements of the Solar Terrestrial Observatory at an early time, a mini-workshop was organized and held on June 6, 1985. The participants at this workshop set as their goal the preliminary definition of the following areas: (1) instrument descriptions; (2) placement of instrumentation on the IOC Space Station; (3) servicing and repair assessment; and (4) operational scenarios. This report provides a synopsis of the results of that workshop.

Roberts, W. T. (editor)

1986-01-01

386

Messaging to Extra-Terrestrial Intelligence  

E-print Network

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

Alexander Zaitsev

2006-10-05

387

Guiding future research on terrestrial ecosystem disturbance  

NASA Astrophysics Data System (ADS)

With North American ecosystems responsible for drawing hundreds of teragrams of carbon from the atmosphere each year, the tenuous balance of the terrestrial carbon budget can be upset for decades by disturbances such as fires, storms, disease outbreaks, insect infestations, and logging. Research cataloging the effects of such disturbances on regional carbon cycling tends to be sporadic or of limited scope. Most research has focused on forests but is less extensive for other important ecosystems such as grasslands or permafrost peatlands.

Schultz, Colin

2013-04-01

388

WATER VAPOUR ABSORPTION IN TERRESTRIAL ISOPODS  

Microsoft Academic Search

Summary Continuous and intermittent gravimetric measurements have identified active water vapour absorption (WVA) in three species of terrestrial Isopoda. Water activity thresholds for uptake lie in the range 0.92-0.95. Above the threshold, WVA shows non-saturated kinetics; the rectum apparently serves as a supplemen- tary avenue for fluid resorption during rapid uptake. Standardized uptake fluxes, corrected for vapour pressure deficit, can

JONATHAN C. WRIGHT; JOHN MACHIN

1990-01-01

389

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

390

The Nitrogen Cycle in Terrestrial Ecosystems  

Microsoft Academic Search

The terrestrial nitrogen (N) cycle comprises soil, plant and animal pools that contain relatively small quantities of biologically\\u000a active N, in comparison to the large pools of relatively inert N in the lithosphere and atmosphere, but that nevertheless\\u000a exert a substantial influence on the dynamics of the global biogeochemical N cycle. After carbon (ca. 400 g kg?1) and oxygen (ca.

Ann McNeill; Murray Unkovich

391

Physiology of exolaccase production by Thelephora terrestris  

Microsoft Academic Search

Thelephora terrestris, an ectomycorrhizal hymenomycete, produces extracellular laccase when grown in minimal liquid medium. The enzyme was characterized as a protein of 66 kDa. The optimal pH varied depending on the substrate utilized, being 5.0 for syringaldazine, 4.8 for guaiacol and 3.4 for ABTS. The Km was 2.52±0.4 ?M for syringaldazine, 16±1.9 ?M for ABTS and 120.6±4.9 ?M for guaiacol.

Carla C Kanunfre; Glaci T Zancan

1998-01-01

392

Alarm pheromone in the earthworm Lumbricus terrestris.  

PubMed

Noxious stimulation of the earthworm Lumbricus terrestris elicits secretion of a mucus that is aversive to other members of the species, as well as to the stimulated animal when it is encountered later. This alarm pheromone is not readily soluble in water and retains its aversive properties for at least several months if not disturbed. Its influence may be responsible for some features of the data on instrumental learning in earthworms. PMID:5663305

Ressler, R H; Cialdini, R B; Ghoca, M L; Kleist, S M

1968-08-01

393

Observed beaming of terrestrial myriametric radiation  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

394

Testbed for Satellite and Terrestrial Interoperability (TSTI)  

NASA Technical Reports Server (NTRS)

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

Gary, J. Patrick

1998-01-01

395

Comparison Charts of Geological Processes: Terrestrial Planets  

NSDL National Science Digital Library

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

396

Emerging Technological Needs for Terrestrial Biogeochemistry Measurements  

NASA Astrophysics Data System (ADS)

With the Earth's climate, flora, and fauna undergoing rapid change, understanding terrestrial ecosystem processes and their sensitivity to environmental and biotic conditions has become paramount. Many theories and models remain rudimentary due to sensor and environmental data inadequacies that persist despite rapid developments in sensor, computing, and networking technologies. This situation has prompted researchers to focus on the development of novel sensors to vastly improve our capability of capturing the high spatial and temporal variations within biogeochemical processes.

Hamada, Yuki; Graham, Robin L.; Matamala, Roser

2013-12-01

397

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

398

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

NASA Astrophysics Data System (ADS)

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

Xu, Lingzhe; Yang, Shihai

2010-07-01

399

Terrestrial water fluxes dominated by transpiration.  

PubMed

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

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

2013-04-18

400

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

401

Space Communication  

Microsoft Academic Search

As the space era approaches, the importance of including space science in the general curriculum and communicating space science to the general public is becoming extremely important. The paper, points out that the inclusion of more space education in the school curriculum and to the general public will increase awareness and interest in the new developments of space exploration. The

Bhavini Patel

2002-01-01

402

Prioritized Communication  

E-print Network

Agent Communication Benjamin Grosof bgrosof@mit.edu http://www.mit.edu/people/bgrosof/home.html MIT = Foundation for Intelligent Physical Agents, an industry standards organization. http://www.fipa.org UMBC in ContractNet FIPA protocol. -- Importance of non­monotonicity for SL role in FIPA ACL . 5. Current

Polz, Martin

403

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

404

Vendor Communication  

ERIC Educational Resources Information Center

Do vendor reps provide librarians with the information they need in the way they need it? Do vendors feel they are communicating effectively with their librarian clients? A recent survey of North American and European academic librarians commissioned by Jim McGinty, vice chair of Cambridge Information Group, and carried out by consultants David…

Tenopir, Carol

2005-01-01

405

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

406

Contracts & Communication  

Microsoft Academic Search

Feelings of guilt may influence trust & cooperation. This can affect partnership interaction so that market failure due to hidden information is avoided. Communication may help further as words move beliefs to make guilt matter more. We analyze whether and how these claims are valid in a framework that merges contract theory with psychological games. Predictions are derived regarding the

Gary Charness; Martin Dufwenberg

407

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)

2008-02-26

408

Information & Communications  

E-print Network

ändert sich in Abhängigkeit von der Zeit und der Hirnaktivität (,,LTP, LTD".....) #5 ! ' #12;© Siemens AG IC 4, 2003 Information & Communications Neural Computation EmotionLong Term Memory Working Memory Attentional Filtering Object/Spatial Memory Rule Memory Attention Object-Based Attention, Spatial Attention

Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

409

Communication & Aging.  

ERIC Educational Resources Information Center

This extensive bibliography contains more than 1,800 entries about communication and aging. The citations include journal articles, unpublished papers, speeches, dissertations, research studies, and books that relate aging and the aged to a variety of topics, including the following: physiological deterioration, socialization, political…

Arnold, William E.

410

Communications Development,  

E-print Network

Research Methods, ELEC6021 (EZ619) S Chen What's New in Communications #15; Imagine a few scenarios course, we only go through some A B C 1 Research Methods, ELEC6021 (EZ619) S Chen Wireless and Mobile network 2 Research Methods, ELEC6021 (EZ619) S Chen For Those Keen to Read #15; Any good text books

Chen, Sheng

411

Bibliometrics, Scholarly Communication, and Communication Research.  

ERIC Educational Resources Information Center

Considers the relationship of communication research to bibliometrics and scholarly communication. Discusses whether bibliometrics is a communication research method; the future of bibliometrics in communication research; bibliometrics in the context of indicator research; articles in this themed issue, seen from a communication research…

Paisley, William

1989-01-01

412

Communication Minor Boston University College of Communication  

E-print Network

Communication Minor Boston University College of Communication Pre-reqUisite: Students must. The student must have the Mass Communication, Advertising and Public Relations department sign off.0 in all courses taken toward the COM minor. Communication encompasses three focus areas: ·Communication

Goldberg, Bennett

413

Communication Minor Boston University College of Communication  

E-print Network

Communication Minor Boston University College of Communication Pre-reqUisite: Students must have the Mass Communication, Advertising and Public Relations department sign off on the COM Minor Form taken toward the COM minor. Communication encompasses three focus areas: ·Communication

414

Communication Engineering Systems Introduction to Communication Systems  

E-print Network

Communication Engineering Systems Introduction to Communication Systems (1) Assoc .. 4 #12;Outline Variety of Today's Communication SystemsVariety of Today s Communication Systems Design Challenges Basic of Communication Systems F d t l Li it tiFundamental Limitation Bandwidth

Kovintavewat, Piya

415

Communication Systems Chair of Communication Systems  

E-print Network

1 | 28 Communication Systems 15th lecture Chair of Communication Systems Department of Applied Sciences University of Freiburg 2008 #12;2 | 28 Communication Systems Organization Last lecture networking issues Starting into second part of "Communication Systems" ­ I. Data and voice communication

Schindelhauer, Christian

416

Communication Systems Chair of Communication Systems  

E-print Network

1 | 36 Communication Systems 24th lecture Chair of Communication Systems Department of Applied Sciences University of Freiburg 2009 #12;2 | 36 Communication Systems last to final lecture Extension;3 | 36 Communication Systems GSM interfaces and components #12;4 | 36 Communication Systems GSM

Schindelhauer, Christian

417

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

418

Astronomy Communication  

NASA Astrophysics Data System (ADS)

Astronomers communicate all the time, with colleagues of course, but also with managers and administrators, with decision makers and takers, with social representatives, with the news media, and with the society at large. Education is naturally part of the process. Astronomy communication must take into account several specificities: the astronomy community is rather compact and well organized world-wide; astronomy has penetrated the general public remarkably well with an extensive network of associations and organizations of aficionados all over the world. Also, as a result of the huge amount of data accumulated and by necessity for their extensive international collaborations, astronomers have pioneered the development of distributed resources, electronic communications and networks coupled to advanced methodologies and technologies, often much before they become of common world-wide usage. This book is filling up a gap in the astronomy-related literature by providing a set of chapters not only of direct interest to astronomy communication, but also well beyond it. The experts contributing to this book have done their best to write in a way understandable to readers not necessarily hyperspecialized in astronomy nor in communication techniques while providing specific detailed information, as well as plenty of pointers and bibliographic elements. This book will be very useful for researchers, teachers, editors, publishers, librarians, computer scientists, sociologists of science, research planners and strategists, project managers, public-relations officers, plus those in charge of astronomy-related organizations, as well as for students aiming at a career in astronomy or related space science. Link: http://www.wkap.nl/prod/b/1-4020-1345-0

Heck, A.; Madsen, C.

2003-07-01

419

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

420

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

421

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

422

Understanding Droughts and their Agricultural Impact in North America at the Basin Scale through the Development of Satellite Based Drought Indicators  

NASA Astrophysics Data System (ADS)

Drought is a major constraint severely affecting numerous agricultural regions in North America. Decision makers need timely information on the existence of a drought as well as its intensity, frequency, likely duration, and economic and social effects in order to implement adaptation strategies and minimize its impacts. Countries like Mexico and Canada face a challenge associated with the lack of consistent and reliable in-situ data that allows the computation of drought indicators at resolutions that effectively supports decision makers at the watershed scale. This study focuses on (1) the development of near-real time drought indicators at high resolution utilizing various satellite data for use in improving adaptation plans and mitigation actions at the basin level; (2) the quantification of the relationships between current and historical droughts and their agricultural impacts by evaluating thresholds for drought impacts; and (3) the assessment of the effects of existing water policies, economic subsidies, and infrastructure that affect the vulnerability of a particular region to the economic impacts of a drought. A pilot study area located in Northwest Mexico and known as the Rio Yaqui Basin was selected for this study in order to make comparisons between the satellite based indicators derived from currently available satellite products to provide an assessment of the quality of the products generated. The Rio Yaqui Basin, also referred to as the "bread basket" of Mexico, is situated in an arid to semi-arid region where highly sophisticated irrigation systems have been implemented to support extensive agriculture. Although for many years the irrigation systems acted as a safety net for the farmers, recent droughts have significantly impacted agricultural output, affected thousands of people, and increase the dependence on groundwater. The drought indices generated are used in conjunction with a decision-support model to provide information on drought impacts and to identify times when drought intensity has exceeded local index thresholds for drought intensity and impacts on a regional basis. Future work includes the selection of several additional drought-prone areas located in Southwest United States, Northwest Mexico, and the Palliser Triangle in Canada and the comparison of national policies associated with drought mitigation programs.

Munoz Hernandez, A.; Lawford, R. G.

2012-12-01

423

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

424

Combined uncertainty of hydrological model complexity and satellite-based forcing data evaluated in two data-scarce semi-arid catchments in Ethiopia  

NASA Astrophysics Data System (ADS)

In water resources modeling, meteorological data scarcity can be compensated by various global data sets, but those data sets can differ tremendously. In the literature, hydrological models of differing complexity are proposed for estimating the water resources of semi-arid catchments, and also to evaluate rainfall data sets. The goal of this paper is to provide a joint analysis of modeling uncertainty due to different input data and increasing model complexity. Impacts of mutually concealed uncertainties on model performance and model outputs are exemplified in two data sparse semi-arid catchments in Ethiopia. We applied a semi-distributed and a fully distributed hydrological model, having different levels of complexity. Three different satellite-based rainfall data sets and two temperature products were used as model inputs. The semi-distributed model demonstrated good validation performances, while the fully distributed model was more sensitive to data uncertainties. The application of TRMM version 6 completely failed and the high-resolution CMORPH precipitation estimate outperformed TRMM version 7. In contrast, the use of high-resolution temperature data did not improve the model results. The large differences in remotely sensed input data were buffered inside the hydrological models. Therefore, data set evaluations regarding only the simulated hydrographs were less meaningful. In contrast, the investigation of parameter evolution and distributed outputs' variability appeared to be a valuable tool to uncover the interdependencies of data and model uncertainties. We suggest this procedure to be applied by default in water resources estimations that are affected by data scarcity, but especially when data sets are evaluated using hydrological models. Our case study demonstrates that estimations of groundwater recharge and actual evapotranspiration vary largely, depending on the applied data sets and models. The joint analysis reveals large interdependencies between data and model evaluations. It shows that traditional studies focusing only on one part of uncertainty, either the input uncertainty or the uncertainty arising from the choice of model structure are limited in their explanatory power of the modeling performance, particularly in poorly gauged regions.

Knoche, Malte; Fischer, Christian; Pohl, Eric; Krause, Peter; Merz, Ralf

2014-11-01

425

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

NASA Astrophysics Data System (ADS)

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

Long, Di; Singh, Vijay P.

2013-05-01

426

Diagnosing Variabilities/Changes in Global Precipitation on the Interannual-to-Interdecadal Time Scales Using Satellite-Based Measurements and Model Outputs  

NASA Astrophysics Data System (ADS)

This study aims to quantify the characteristics of global precipitation variations on the interannual-to-interdecadal time scales using the over 30-year (1979-present) satellite-based precipitation data from the Global Precipitation Climatology Project (GPCP), the recently-archived AMIP5 runs, and the two state-of-the-art reanalysis products, i.e., the NASA/GSFC-Modern Era Retrospective-Analysis for Research and Applications (MERRA) and the NOAA-20th Century Reanalysis (20CR) Project. The objectives here are to explore physical mechanisms behind interannual-to-interdecadal precipitation variations during the past three decades (1979-present), and to understand/assess the strengths and weaknesses of the precipitation estimates and other associated hydrological-cycle components in the state-of-the-art model simulations and reanalysis products. On the interannual time scale, the AMIP5 runs and reanalysis products could catch very well the major (spatial and temporal) features of precipitation variations associated with the El Niño-Southern Oscillation (ENSO) during the past three decades (1979-present) compared to what described by GPCP. The first two EOF modes of global precipitation anomalies in general correspond to the "classic" tropical eastern Pacific warming/cooling events and the so-called "dateline events" occurring in the tropical central Pacific, respectively. The model-based outputs including both the AMIP5 runs and reanalysis products can also provide a good account of the ENSO related spatial and temporal variations in tropospheric integrated water vapor content and tropospheric temperature. Observational analyses indicate that the interdecadal/long-term variabilities in global precipitation during the past three decades might be a combination of the global warming related variation and the changes associated with a climate regime shift around or after the 1997/1998 El Niño event. This regime shift is likely related to the Pacific Decadal Variability (PDV). The CMIP5 and the 20CR precipitation and columnar water vapor fields seem to be able to replicate these variabilities. This thus provides confidence not only in the AMIP5 runs and the 20CR product for further exploring the interdecadal and long-term variabilities that have already happened in the past decades, but also in the CMIP5 runs for assessing the possible, projected changes in the coming decades.

Gu, G.; Adler, R. F.

2012-12-01

427

Construction of an Inexpensive Sun Photometer for Measuring Aerosols Optical Depth (AOD) and Comparison Between the Ground Based and Satellite Based Measurements  

NASA Astrophysics Data System (ADS)

Aerosols influence our weather and climate because they affect the amount of sunlight reaching Earth's surface. An important way of probing the atmosphere from the ground is to measure the effects of the atmosphere on sunlight transmitted through the atmosphere to Earth's surface. These indirect techniques provide information about the entire atmosphere above the observer, not just the atmosphere that can be sampled directly. In response to global issues of air quality and climate change, and to the need to improve the quality of science education, inexpensive atmosphere monitoring instruments have been developed. This paper describes a new kind of inexpensive two channels LED Sun Photometer for monitoring aerosols that provide much better long-term stability than instruments that use expensive interference filters. Here HAZE-SPAN TERC VHS-1 model has been used for constructing sun photometer with light emitting diode as detector. Monitoring Earth's atmosphere is a challenging task. As there is no facility in our country (Bangladesh) for ground based measurement for monitoring aerosol so, this type of study is very essential. This study compares the aerosol optical depth (AOD) retrieved from the Terra and Aqua MODerate Resolution Imaging Spectroradiometers (MODIS) with ground-based measurements from a handheld sun photometer over the region of Rajshahi, Bangladesh for The 15 days duration of June 2012. The results indicate that the Terra and Aqua MODIS AOD retrievals at 550 nm have good correlations with the measurements from the handheld sun photometer. The correlation coefficients r = 0.88 for Terra and r = 0.55 for Aqua where as r = 0.65 for Terra and Aqua themselves. AOD for another wavelength at 625 nm is documented in this study for finding out the relation of AOD at different wavelengths. In this paper it has been described and summarized briefly investigations for four important topics: LEDs used as light detectors, construction of sun photometer and its use, the measurements and monitoring of Aerosol Optical Depth (AOD) by using handheld sun photometer, and the comparison between satellite based and ground based measurements.