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1

Design of Optimal Topology of Satellite-Based Terrestrial Communication Networks  

E-print Network

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

Verkhovsky, Boris S

2010-01-01

2

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

3

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; McCabe, Kevin P [Los Alamos National Laboratory; Newell, Raymond T [Los Alamos National Laboratory; Peterson, Charles G [Los Alamos National Laboratory

2010-09-20

4

Digital, Satellite-Based Aeronautical Communication  

NASA Technical Reports Server (NTRS)

Satellite system relays communication between aircraft and stations on ground. System offers better coverage with direct communication between air and ground, costs less and makes possible new communication services. Carries both voice and data. Because many data exchanged between aircraft and ground contain safety-related information, probability of bit errors essential.

Davarian, F.

1989-01-01

5

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

6

Low earth orbit satellite based communication systems — Research opportunities  

Microsoft Academic Search

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

Bezalel Gavish

1997-01-01

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

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

Microsoft Academic Search

Abstract 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 the satellite-based carbon flux estimates. Here,

David P. Turner; William D. Ritts; Warren B. Cohen; Thomas K. Maeirsperger; Stith T. Gowers; Al A. Kirschbaums; Steve W. Runnings; Maosheng Zhaos; Steven C. Wofsyy; Allison L. Dunnt; Beverly E. Law; John L. Campbell; Walter C. Oechelii; Hyo Jung Kwonii; Tilden P. Meyers; Eric E. Small; S Hirley A. Kurc; John A. Gamon

9

Spacetime effects on satellite-based quantum communications  

E-print Network

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

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

2013-01-01

10

Spacetime effects on satellite-based quantum communications  

E-print Network

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.

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

2013-09-12

11

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

12

Network design consideration of a satellite-based mobile communications system  

NASA Technical Reports Server (NTRS)

Technical considerations for the Mobile Satellite Experiment (MSAT-X), the ground segment testbed for the low-cost spectral efficient satellite-based mobile communications technologies being developed for the 1990's, are discussed. The Network Management Center contains a flexible resource sharing algorithm, the Demand Assigned Multiple Access scheme, which partitions the satellite transponder bandwidth among voice, data, and request channels. Satellite use of multiple UHF beams permits frequency reuse. The backhaul communications and the Telemetry, Tracking and Control traffic are provided through a single full-coverage SHF beam. Mobile Terminals communicate with the satellite using UHF. All communications including SHF-SHF between Base Stations and/or Gateways, are routed through the satellite. Because MSAT-X is an experimental network, higher level network protocols (which are service-specific) will be developed only to test the operation of the lowest three levels, the physical, data link, and network layers.

Yan, T.-Y.

1986-01-01

13

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

14

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

15

Design considerations of terrestrial communications system  

Microsoft Academic Search

We study design considerations, measure of effectiveness (MOE) factors, for tactical communications system. Terrestrial communications system (TCS) architecture for army is described and the link delay performance as a grade of service (GOS) factor is analyzed. One can see that flood search routing algorithm in mesh networks is well suited for tactical communications network and survivability requirements.

Y. C. Park

2007-01-01

16

Inflatable antennas for portable direct satellite communication.  

E-print Network

??Satellite-based communication system can provide access to voice, data, video and internet transmission that is independent of terrestrial infrastructure. This is particularly important in disaster… (more)

Mathers, N

2010-01-01

17

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

18

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

Microsoft Academic Search

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

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

2005-01-01

19

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

20

LOCOMOTION (TERRESTRIAL AND AERIAL) AND COMMUNICATION OF AUTONOMOUS ROBOT NETWORKS  

E-print Network

1 LOCOMOTION (TERRESTRIAL AND AERIAL) AND COMMUNICATION OF AUTONOMOUS ROBOT NETWORKS Arvin Agah This report focuses on locomotion and communication aspects of mobile robot networks for harsh polar environments. The report is organized into seven sections: terrestrial locomotion, aerial locomotion, micro air

Kansas, University of

21

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

E-print Network

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

Peraire, Jaime

22

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

23

Performance of power-controlled wideband terrestrial digital communication  

Microsoft Academic Search

Performance of a wideband multipath-fading terrestrial digital coded communication system is treated. The analysis has applications to a cellular system using direct-sequence spread-spectrum code-division multiaccess (CDMA) with M-ary orthogonal modulation on the many-to-one reverse (user-to-base station) link. For these links, power control of each multiple-access user by the cell base station is a critically important feature. This feature is implemented

Andrew J. Viterbi; Audrey M. Viterbi; Ephraim Zehavi

1993-01-01

24

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

25

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

26

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

27

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

NASA Technical Reports Server (NTRS)

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

Ivancic, William D.

1998-01-01

28

Satellite-based laser windsounder  

SciTech Connect

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

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

1997-08-01

29

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

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

30

Comparison of global net primary production trends obtained from satellite-based normalized difference vegetation index and carbon cycle model  

Microsoft Academic Search

The global terrestrial net primary production (NPP) trend was estimated from two independent methods, satellite observation data and a carbon cycle model, and the results were compared for validation. The satellite-based NPP trend was estimated from the incoming surface solar radiation data set and a National Oceanic and Atmospheric Administration\\/Advanced Very High Resolution Radiometer data set that was corrected by

Kazuhito Ichii; Yohei Matsui; Yasushi Yamaguchi; Katsuro Ogawa

2001-01-01

31

The Neural and Behavioral Basis of Chemical Communication in Terrestrial Crustaceans  

Microsoft Academic Search

\\u000a Within Crustacea, representatives of at least five major taxa have succeeded in the transition from an aquatic to a fully\\u000a terrestrial lifestyle: Isopoda, Amphipoda, Astacida, Anomura, and Brachyura. Land-living crustaceans are fascinating animals\\u000a that during a very limited time period at an evolutionary time scale have adapted to a number of diverse terrestrial habitats\\u000a in which they have become highly

Bill S. Hansson; Steffen Harzsch; Markus Knaden; Marcus Stensmyr

32

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

Microsoft Academic Search

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

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

2005-01-01

33

14 CFR 121.122 - Communications facilities-supplemental operations.  

...must have a second communication system in addition...to provide immediate satellite-based voice communications of landline telephone-fidelity...Where immediate, satellite-based voice communications are not...

2014-01-01

34

Poster Abstract: Satellite Based Wireless Sensor Networks Global Scale Sensing with Nano-and Pico-Satellites  

E-print Network

, Earth Observation, inter-satellite communication, nano- pico-satellite. 1. INTRODUCTION Traditional challenges mainly related to inter-satellite communication and routing. These similarities and challePoster Abstract: Satellite Based Wireless Sensor Networks ­ Global Scale Sensing with Nano

Dunkels, Adam

35

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

36

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

...must have a second communication system in addition...to provide immediate satellite-based voice communications of landline-telephone...Where immediate, satellite-based voice communications are not...

2014-01-01

37

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

38

Satellite-Based Educational Services. Technical Memorandum.  

ERIC Educational Resources Information Center

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

Operations Research, Inc., Silver Spring, MD.

39

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

40

"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

41

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

ERIC Educational Resources Information Center

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

Beyth-Marom, Ruth; Saporta, Kelly

42

Internetworking satellite and local exchange networks for personal communications applications  

NASA Technical Reports Server (NTRS)

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

Wolff, Richard S.; Pinck, Deborah

1993-01-01

43

ExtraTerrestrial Intelligence  

E-print Network

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

Walter, Frederick M.

44

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

45

Application of Satellite Based Augmentation Systems to Altitude Separation  

NASA Astrophysics Data System (ADS)

This paper presents the application of GNSS1, or more precisely of Satellite Based Augmentation Systems (SBAS), to vertical separation for en-route, approach and landing operations. Potential improvements in terms of operational benefit and of safety are described for two main applications. First, vertical separation between en-route aircraft, which requires a system available across wide areas. SBAS (EGNOS, WAAS, and MSAS) are very well suited for this purpose before GNSS2 becomes available. And secondly, vertical separation from the ground during approach and landing, for which preliminary design principles of instrument approach procedures and safety issues are presented. Approach and landing phases are the subject of discussions within ICAO GNSS-P. En-route phases have been listed as GNSS-P future work and by RTCA for development of new equipments.

Magny, Jean Pierre

46

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

47

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

48

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

49

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

50

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

51

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

52

Computational Considerations for Satellite-Based Geopotential Recovery  

Microsoft Academic Search

\\u000a This contribution addresses computational considerations in the framework of the main inverse problem in geodetic research,\\u000a i.e., the determination of the terrestrial gravitational potential. The computational considerations comprise strategies for\\u000a both the solution of the underlying systems of equations in order to resolve the model parameters and the estimation of the\\u000a parameter variance-covariance information.

O. Baur; W. Keller

53

Using Satellite Based Techniques to Combine Volcanic Ash Detection Methods  

NASA Astrophysics Data System (ADS)

Volcanic ash poses a serious threat to aircraft avionics due to the corrosive nature of the silicate particles. Aircraft encounters with ash have resulted in millions of dollars in damage and loss of power to aircraft engines. Accurate detection of volcanic ash for the purpose of avoiding these hazardous areas is of the utmost importance to ensure aviation safety as well as to minimize economic loss. Satellite-based detection of volcanic ash has been used extensively to warn the aviation community of its presence through the use of multi-band detection algorithms. However, these algorithms are generally used individually rather than in combination and require the intervention of a human analyst. Automation of the detection and warning of the presence of volcanic ash for the aviation community is a long term goal of the Federal Aviation Administration Oceanic Weather Product Development Team. We are exploring the use of data fusion techniques within a fuzzy logic framework to perform a weighted combination of several multi-band detection algorithms. Our purpose is to improve the overall performance of volcanic ash detection and to test whether automation is feasible. Our initial focus is on deep, stratospheric eruptions.

Hendrickson, B. T.; Kessinger, C.; Herzegh, P.; Blackburn, G.; Cowie, J.; Williams, E.

2006-12-01

54

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 of solar dataset or time-series is addressed with the example of the French national meteorological network

Recanati, Catherine

55

Operational Satellite-based Surface Oil Analyses (Invited)  

NASA Astrophysics Data System (ADS)

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

Streett, D.; Warren, C.

2010-12-01

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

Terrestrial ecology  

Microsoft Academic Search

Terrestrial studies continue to contribute ideas and ecological data ; relevant to nuclear-power plant siting and the management of stored radioactive ; wastes in the semi-arid steppe region of Washington. These ideas and data are ; also largely applicable to steppe regions of Oregon, Idaho, and Nevada. Much of ; the available information concerning the ecology of steppe ecosystems has

1974-01-01

58

TERRESTRIAL ECOTOXICOLOGY  

EPA Science Inventory

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

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

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

E-print Network

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

Atiquzzaman, Mohammed

61

Terrestrial Planets  

NASA Astrophysics Data System (ADS)

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

Barlow, Nadine G.

62

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

63

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

E-print Network

Recent climate and fire disturbance impacts on boreal and arctic ecosystem productivity estimated ecosystem CO2 exchange (NEE) over a pan-boreal/Arctic domain and their sensitivity to climate variability simulations also tracked post-fire NEE recovery indicated from three boreal tower fire chronosequence networks

Montana, University of

64

Utilizing PERSIANN Satellite-based precipitation dataset for hydrologic applications (Invited)  

NASA Astrophysics Data System (ADS)

Recent development of satellite-based retrieval techniques has made it possible for monitoring precipitation events over remote regions. In this presentation, satellite-based global precipitation monitoring systems developed at UC Irvine will be presented. Those developed algorithms are operated to estimate near real-time global precipitation as well as to give retrospective estimation of precipitation climatology. A long-term daily precipitation dataset, named PERSIANN-Precipitation Climate Data Record (PERSIANN-CDR), is developed to estimate precipitation at daily and 0.25ox0.25o scale from 1980 to near current time. The dataset can be very useful for hydro-climatological studies. This presentation will also cover our experiments of using satellite-based precipitation products for catchment scale streamflow simulation and in the impact of precipitation uncertainty on the hydrological responses.

Hsu, K.

2013-12-01

65

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

66

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

67

Validation of PV performance models using satellite-based irradiance measurements : a case study.  

SciTech Connect

Photovoltaic (PV) system performance models are relied upon to provide accurate predictions of energy production for proposed and existing PV systems under a wide variety of environmental conditions. Ground based meteorological measurements are only available from a relatively small number of locations. In contrast, satellite-based radiation and weather data (e.g., SUNY database) are becoming increasingly available for most locations in North America, Europe, and Asia on a 10 x 10 km grid or better. This paper presents a study of how PV performance model results are affected when satellite-based weather data is used in place of ground-based measurements.

Stein, Joshua S.; Parkins, Andrew (Clean Power Research); Perez, Richard (University at Albany)

2010-05-01

68

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

69

An Alternative Ionospheric Correction Algorithm for Satellite-Based Augmentation Systems in Low-Latitude Region  

Microsoft Academic Search

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

Attila Komjathy; Lawrence Sparks; Tony Mannucci; Xiaoqing Pi

70

COASTAL CURRENTS MONITORING USING RADAR SATELLITES BASED ON WAVE TRACKING APPROACH  

E-print Network

COASTAL CURRENTS MONITORING USING RADAR SATELLITES BASED ON WAVE TRACKING APPROACH A. Abedini1 , M WORDS: Coastal Currents, Monitoring, Jason1 Satellite, Wave Tracking, Radar Satellites ABSTRACT: Use and protocols such as Google Earth KML and so on. In this study Jason1 satellite data has been used as input

Stuttgart, Universität

71

Reducing Need for Collocated Ground and Satellite based Observations in Statistical Aerosol Optical Depth Estimation  

E-print Network

prediction of Aerosol Optical Density (AOD) which is defined as the amount of loss a beam of light incurs of solar radiation. An important metric of aerosol's concentration in the atmosphere is Aerosol OpticalReducing Need for Collocated Ground and Satellite based Observations in Statistical Aerosol Optical

Vucetic, Slobodan

72

Communication  

Microsoft Academic Search

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

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

73

47 CFR 1.9049 - Special provisions relating to spectrum leasing arrangements involving the ancillary terrestrial...  

...terrestrial component of Mobile Satellite Services. 1.9049 Section...Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE...terrestrial component of Mobile Satellite Services. (a) A license...of this subpart, a Mobile Satellite Service licensee with...

2014-10-01

74

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

75

Communications  

ERIC Educational Resources Information Center

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

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

2013-01-01

76

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

77

Satellite-based detection of Canadian boreal forest é res: development and application of the algorithm  

Microsoft Academic Search

This study presents a comprehensive investigation of é res across the Canadian boreal forest zone by means of satellite-based remote sensing. A é re- detection algorithm was designed to monitor é res using daily Advanced Very High Resolution Radiometer (AVHRR) images. It exploits information from multichannelAVHRR measurementstodeterminethe locationsofé reson satellite pixels of about 1km2 under clear sky or thin smoke

Z. LI; S. NADON; J. CIHLAR

2000-01-01

78

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

E-print Network

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

Mailhes, Corinne

79

Impact of atmospheric variability on validation of satellite-based temperature measurements  

NASA Astrophysics Data System (ADS)

Satellite validation is often based on straight forward comparison of satellite-based data with non-satellite based measurements. For functional reasons satellite and reference measurements do usually not correspond exactly in time and space. Dynamical effects in the atmosphere lead to temporal and spatial variability of atmospheric parameters (e.g. temperature). This causes considerable differences that do not necessarily hint to an incorrect satellite measurement, so called mistime and misdistance errors. In this paper, the natural variability of the atmosphere is studied on scales effecting validation measurements. The approach is applied to temperature data from the ERA-40 reanalysis as well as to radiosonde (SIGMA-1) and satellite-based (SABER) measurements. Mistime and misdistance errors are quantified in dependence of geographic position, altitude, season and the temporal and spatial mismatch. The results allow a quantitative estimation of the impact of natural variability on validation analyses. In general, values lie in the range of a few Kelvin (e.g. up to 5 K for 500 km misdistance or 6 h mistime in the stratosphere), which indicates considerable effects on validation results. The determined results also point out regions in the atmosphere where the impact of natural variability is in general relatively high (e.g. the winter stratosphere in mid-latitudes) or rather low (e.g. the lower summer stratosphere). Altitudes, which are characterized systematically by only small mismatch errors, are indicated at about 10 and 25 km, respectively. These quiet layers are of special interest for validation activities.

Wendt, Verena; Wüst, Sabine; Mlynczak, Martin G.; Russell, James M.; Yee, Jeng-Hwa; Bittner, Michael

2013-09-01

80

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

81

Entanglement-based quantum communication over 144km  

E-print Network

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

Loss, Daniel

82

SETI: Search for ExtraTerrestrial Intelligence  

E-print Network

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

Walter, Frederick M.

83

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

84

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

Microsoft Academic Search

Potassium tantalate niobate (KTN) pyroelectric detectors are expected to provide detectivities of 3.7× 10sp{11}\\\\ cmHzsp{1\\/2}Wsp{-1} for satellite-based infrared detection at 90 K. The background limited detectivity for a room-temperature thermal detector is 1.8× 10sp{10}\\\\ cmHzsp{1\\/2}Wsp{-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

Hilary Beatrix Baumann Cherry; H. B. B

1997-01-01

85

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

86

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

87

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

88

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

E-print Network

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

Gesbert, David

89

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

90

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

USGS Publications Warehouse

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

Van Den Hoek, Jamon; Read, Jordan S.; Winslow, Luke A; Montesano, Paul; Markfort, Corey D

2014-01-01

91

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

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

Dalmonech, D.; Zaehle, S.

2013-06-01

92

The Global Terrestrial Water Cycle Earth System Data Record  

NASA Astrophysics Data System (ADS)

A new balanced global terrestrial water cycle information has been created for NASAs' Making Earth Science Data Records for use in Research Environments (MEaSURE) project. It is comprised of multiple remotely-sensed and model generated data, and has been merged into a single unified multi-decade, high spatial resolution, climate consistent Earth Science Data Record (ESDR). In addition to the unified ESDR, the seven remotely-sensed and model generated input datasets are also available as ESDRs. These 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 - 2009, on a 0.5 degree grid) (7) Model derived Surface Meteorological Forcing Fields (3 hourly, from 1948 - 2010, on a 0.25 degree grid). This poster illustrates the methodology used to generate the final unified ESDR. The poster gives an overview of the input datasets and the components of the output dataset. Additionally, some of the major challenges in the creation of this dataset are also illustrated, such as understanding where sources of temporal and spatial differences occur between datasets, and biases and uncertainties along with how these challenges were reconciled. These datasets are available through the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC), as well as from a dedicated project server, at George Mason University, and are 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.

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

2013-12-01

93

Terrestrial Planets: Comparative Planetology  

NASA Technical Reports Server (NTRS)

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

1985-01-01

94

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

95

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

NASA Technical Reports Server (NTRS)

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

Bos, Andre; Callies, Jorg; Lefebvre, Alain

1995-01-01

96

Trellis-coded CPM for wireless communications  

Microsoft Academic Search

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

F. Abrishamkar; E. Biglieri

1993-01-01

97

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

98

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

NASA Astrophysics Data System (ADS)

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

Nonnenmacher, L.; Coimbra, C.

2013-12-01

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

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

101

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

102

Modeling and evaluation of aerial layer communications system architectures  

E-print Network

Airborne networks are being developed to provide communications services in order to augment space-based and terrestrial communications systems. These airborne networks must provide point to point wireless communications ...

Ajemian, Stephen P

2014-01-01

103

Terrestrial Planet Finder  

NASA Technical Reports Server (NTRS)

Integrating and testing the proposed Terrestrial Planet Finder imposes constraints on the design. Some of these will be discussed including the dimensions of existing test facilities, the effects of gravity, ambient vibrations and the size of GSE optics.

Smith, Andrew

2004-01-01

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

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

106

A Satellite-based Assessment of Trans-Pacific Transport of Pollution Aerosol  

NASA Technical Reports Server (NTRS)

It has been well documented that pollution aerosol and dust from East Asia can transport across the North Pacific basin, reaching North America and beyond. Such intercontinental transport extends the impact of aerosols for climate change, air quality, atmospheric chemistry, and ocean biology from local and regional scales to hemispheric and global scales. Long term, measurement-based studies are necessary to adequately assess the implications of these wider impacts. A satellite-based assessment can augment intensive field campaigns by expanding temporal and spatial scales and also serve as constraints for model simulations. Satellite imagers have been providing a wealth of evidence for the intercontinental transport of aerosols for more than two decades. Quantitative assessments, however, became feasible only recently as a result of the much improved measurement accuracy and enhanced new capabilities of satellite sensors. In this study, we generated a 4-year (2002 to 2005) climatology of optical depth for pollution aerosol (defined as a mixture of aerosols from urbanlindustrial pollution and biomass burning in this study) over the North Pacific from MODerate resolution Imaging Spectro-radiometer (MODIS) observations of fine- and coarse-mode aerosol optical depths. The pollution aerosol mass loading and fluxes were then calculated using measurements of the dependence of aerosol mass extinction efficiency on relative humidity and of aerosol vertical distributions from field campaigns and available satellite observations in the region. We estimated that about 18 Tg/year pollution aerosol is exported from East Asia to the northwestern Pacific Ocean, of which about 25% reaches the west coast of North America. The pollution fluxes are largest in spring and smallest in summer. For the period we have examined the strongest export and import of pollution particulates occurred in 2003, due largely to record intense Eurasia wildfires in spring and summer. The overall uncertainty of pollution fluxes is estimated at about 80%. A reduction of uncertainty can be achieved with a better characterization of pollution aerosol through integrating emerging A-Train measurements. Simulations by the Goddard Chemistry Aerosol Radiation and Transport (GOCART) and Global Modeling Initiative (GMI) models agree quite well with the satellite-based estimates of annual and latitudeintegrated fluxes, with larger model-satellite differences in latitudinal variations of fluxes.

Yu, Hongbin; Remer, Lorraine; Chin, Mian; Bian, Huisheng; Kleidman, Richard; Diehl. Thomas

2007-01-01

107

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

E-print Network

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

108

int. j. remote sensing, 2000, vol. 21, no. 16, 30573069 Satellite-based detection of Canadian boreal forest res: development  

E-print Network

boreal forest res: development and application of the algorithm Z. LI*, S. NADON and J. CIHLAR Canada a comprehensive investigation of res across the Canadian boreal forest zone by means of satellite-based remote of boreal forest res using AVHRR data (Flannigan and Vonder Haar 1986, Cahoon et al. 1994, Li et al. 1997

Li, Zhanqing

109

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

110

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 ...

111

Formation Flying Control of a Pair of Nano-Satellites Based on Switching Predictive Control F. Bacconi and E. Mosca  

E-print Network

Formation Flying Control of a Pair of Nano-Satellites Based on Switching Predictive Control F of for- mations of nano-satellites subject to input-saturation constraints and persistent disturbances the effectiveness of the proposed approach. I. INTRODUCTION Formation flying of satellites is currently an active

Sontag, Eduardo

112

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 gained from the exploitation of existing Earth observation technologies and will take advantage of the enhanced capabilities of the new Meteosat Second Generation (MSG) satellites. The expected quality

Heinemann, Detlev

113

Terrestrial and Extraterrestrial Fullerenes  

Microsoft Academic Search

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

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

2003-01-01

114

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

E-print Network

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

Baras, John S.

115

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

116

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

117

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

118

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

119

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

120

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

121

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

122

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

123

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

124

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

125

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

126

Weather Information Communications (WINCOMM) Overview and Status  

NASA Technical Reports Server (NTRS)

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

Martzaklis, K.

2003-01-01

127

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

128

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

129

Global terrestrial carbon cycle  

SciTech Connect

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

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

1993-01-01

130

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

131

Satellite-Based Global Precipitation Data Sets at Monthly and Finer Time Scales  

NASA Technical Reports Server (NTRS)

A new 20-year, monthly, globally complete precipitation analysis has been completed as part of the World Climate Research Program's (WCRP/GEWEX) Global Precipitation Climatology Project (GPCP). The global, monthly, 2.5 deg x 2.5 deg latitude-longitude product utilizes precipitation estimates from low-orbit microwave sensors (SSM/1) and geosynchronous IR sensors and raingauge information over land. The low-orbit microwave estimates are used to adjust or correct the geosynchronous IR estimates, thereby maximizing the utility of the more physically-based microwave estimates and the finer time sampling of the geosynchronous data. The 20-year climatology of the Version 2 GPCP analysis indicates the expected features of a very strong Pacific Ocean ITCZ and SPCZ with maximum 20-year means approaching 10 mm/day. A similar strength maximum over land is evident over Borneo. Weaker maxima in the tropics occur in the Atlantic ITCZ and over South America and Africa. In mid-latitudes of the Northern Hemisphere the Western Pacific and Western Atlantic maxima have values of approximately 7 mm/day, while in the Southern Hemisphere the mid-latitude maxima are located southeast of Africa, in mid-Pacific as an extension of the SPCZ and southeast of South America. In terms of global totals the GPCP analysis shows 2.7 mm/day (3.0 mm/day over ocean; 2.1 mm/day over land), similar to the Jaeger climatology, but not other climatologies. Zonal averages peak at 6 mm/day at 7 deg N with mid-latitude peaks of about 3 mm/day at 40-45 deg latitude. Poleward of 45 deg the GPCP analysis shows larger zonally-averaged values than most previous satellite-based estimates, although the values are similar to the Jaeger climatology.

Adler, Robert

1999-01-01

132

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

133

Categorizing natural disaster damage assessment using satellite-based geospatial techniques  

NASA Astrophysics Data System (ADS)

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

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

2008-07-01

134

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

135

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

136

A Remotely Sensed Global Terrestrial Drought Severity Index  

NASA Astrophysics Data System (ADS)

Regional drought and flooding from extreme climatic events are increasing in frequency and severity, with significant adverse eco-social impacts. Detecting and monitoring drought at regional to global scales remains challenging, despite the availability of various drought indices and widespread availability of potentially synergistic global satellite observational records. We developed a method to generate a near-real-time remotely sensed Drought Severity Index (DSI) to monitor and detect drought globally at 1-km spatial resolution and regular 8-day, monthly and annual frequencies. The new DSI integrates and exploits information from current operational satellite based terrestrial evapotranspiration (ET) and Vegetation greenness Index (NDVI) products, which are sensitive to vegetation water stress. Specifically, our approach determines the annual DSI departure from its normal (2000-2011) using the remotely sensed ratio of ET to potential ET (PET) and NDVI. The DSI results were derived globally and captured documented major regional droughts over the last decade, including severe events in Europe (2003), the Amazon (2005 and 2010), and Russia (2010). The DSI corresponded favorably (r=0.43) with the precipitation based Palmer Drought Severity Index (PDSI), while both indices captured similar wetting and drying patterns. The DSI was also correlated with satellite based vegetation net primary production (NPP) records, indicating that the combined use of these products may be useful for assessing water supply and ecosystem interactions, including drought impacts on crop yields and forest productivity. The remotely-sensed global terrestrial DSI enhances capabilities for near-real-time drought monitoring to assist decision makers in regional drought assessment and mitigation efforts, and without many of the constraints of more traditional drought monitoring methods.

Mu, Q.; Zhao, M.; Kimball, J. S.; McDowell, N. G.; Running, S. W.

2012-12-01

137

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

138

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

139

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

140

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

141

Retrieval of water quality from China's first satellite-based Hyperspectral Imager (HJ-1A HSI) data  

Microsoft Academic Search

On September 6, 2008, a Micro-satellite Constellation for Monitoring and Forecasting Environment and Disaster was successfully launched in China. This Micro-satellite Constellation includes two small satellites, Satellite-A (abbreviated as HJ-1A) and Satellite-B (abbreviated as HJ-1B). HJ-1A is installed with a Hyperspectral Imager (abbreviated as HSI), which is China's first satellite-based hyperspectral remote sensor. The advantages of HJ-1A HSI is that

Qiao Wang; Junsheng Li; Qian Shen; Chuanqing Wu; Jianlin Yu

2010-01-01

142

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

Microsoft Academic Search

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

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

2011-01-01

143

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

144

Overview of terrestrial thermionics  

Microsoft Academic Search

The application of the thermionic energy conversion systems first designed for spacecraft to terrestrial energy systems entails the development of a method for the protection of the high temperature refractory metals employed from the ambient air. A trilayer structure consisting of a tungsten emitter, a silicon carbide protective layer, and an intermediate graphite substrate, has been fabricated by means of

F. Huffman

1983-01-01

145

Solar-Terrestrial Predictions  

Microsoft Academic Search

Volume 1: The following subject areas are covered: the magnetosphere environment; forecasting magnetically quiet periods; radiation hazards to human in deep space (a summary with special reference to large solar particle events); solar proton events (review and status); problems of the physics of solar-terrestrial interactions; prediction of solar proton fluxes from x-ray signatures; rhythms in solar activity and the prediction

R. J. Thompson; D. G. Cole; P. J. Wilkinson; M. A. Shea; D. Smart

1990-01-01

146

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

147

Terrestrials Dwarf Planets  

E-print Network

Terrestrials Gas Giants Ice Giants Dwarf Planets The Solar System #12;Neptune Uranus Saturn Jupiter Density: 3900 ­ 5500 kg m-3 #12;Jupiter 318 ME 5.2 AU Uranus 15 ME 19.6 AUSaturn 95 ME 9.5 AU Neptune 17 3.88 RE Uranus Neptune Uranus and Neptune are Ice Giants made mostly of ices with thin Hydrogen

Gaudi, B. Scott

148

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

149

Terrestrial analogs to Mars  

NASA Technical Reports Server (NTRS)

It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing.

Farr, T. G.; Arcone, S.; Arvidson, R.; Baker, V.; Barlow, N.; Beaty, D.; Bell, M.; Blankenship, D.; Bridges, N.; Briggs, G.; Bulmer, M.; Carsey, F.; Clifford, S.; Craddock, R.; Dickerson, P.; Duxbury, N.

2002-01-01

150

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

E-print Network

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

Papapetrou, Evaggelos

151

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

152

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

NASA Technical Reports Server (NTRS)

The global air-sea fluxes of momentum, latent and sensible heat, radiation, and freshwater (precipitation-evaporation) are required for driving Ocean models and validating coupled ocean- atmosphere global models. Wind stress is the major forcing for driving the oceanic circulation, while evaporation is a key component of hydrological cycle and surface heat budget. We have produced a 13.5-year (July 1987-December 2000) dataset containing daily, monthly, and climatological surface fluxes of momentum, latent and sensible heat over the global Oceans from the Special Sensor Microwave/Imager (SSM/I) radiance easurements. This dataset is called version 2 Goddard Satellite-based Surface Turbulent Fluxes (GSSTF-2). The GSSW-2 has a spatial resolution of 1.0deg x 1.0deg lat-long. In addition, evaporation has been combined with the satellite-retrieved precipitation to produce monthly freshwater fluxes over the global Ocean for the same period. Daily turbulent fluxes are derived from the S S M surface winds and surface air humidity, and 2-m air and sea surface temperatures (SST) of the NCEP/NCAR reanalysis, using an improved stability-dependent bulk flux algorithm based on the surface layer similarity theory. Hourly fluxes computed from the GSSTF-2 bulk flux algorithm using the observed hourly input variables validate well against those of ten experiments observed by the research ships over the tropical and midlatitude oceans. In addition, daily wind stresses, latent heat fluxes, wind speeds, surface air humidity and SSTs of the GSSTF-2 compare reasonably well with those of the collocated in situ measurements of the ten experiments. The global distributions of 1988-2000 annual- and seasonal-mean turbulent fluxes show reasonable patterns related to the atmospheric general circulation and its seasonal variations. The comparison of zonally-averaged wind stress and latent heat fluxes of the GSSTF-2 with those of other satellite products as well as the NCEPNCAR and ECMWF reanalyses for the annual mean and seasonal variations during 1992-93 will be discussed. .

Chou, Shu-Hsien; Nelkin, Eric; Ardizzone, Joe; Atlas, Robert M.; Shie, Chung-Lin

2002-01-01

153

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

154

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

155

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

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

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

158

Satellite-based assessment of climate controls on US burned area  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

159

Satellite-based assessment of climate controls on US burned area  

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

160

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

161

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

162

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

163

Biological Indicator of Manganese54 Contamination in Terrestrial Environments  

Microsoft Academic Search

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

Raffaele Cavalloro; Oscar Ravera

1966-01-01

164

Terrestrial Digital TV Receiver IP Core & Hardware Platform  

Microsoft Academic Search

The broadcasting of Digital Terrestrial Transmissions (DTT) has lead to many countries planning to phase out existing analog broadcasts. North America starts the official launch of DTT with the Federal Communications Commission (FCC) mandate that by March 2007, all TVs and other devices that are designed to receive broadcast television signals are required to have digital TV (DTV) tuners built

Hossein Dehghan; Bill Black-Hogins

2007-01-01

165

Overview of terrestrial thermionics  

NASA Astrophysics Data System (ADS)

The application of the thermionic energy conversion systems first designed for spacecraft to terrestrial energy systems entails the development of a method for the protection of the high temperature refractory metals employed from the ambient air. A trilayer structure consisting of a tungsten emitter, a silicon carbide protective layer, and an intermediate graphite substrate, has been fabricated by means of chemical vapor deposition. Performance tests have demonstrated excellent results in combustion atmospheres.

Huffman, F.

166

The Terrestrial Planet Finder  

NASA Technical Reports Server (NTRS)

The Terrestrial Planet Finder (TPF) missions has as its goal the detection and characterization of earth-like planets around nearby stars. NASA is currently funding a number of small studies to look at the trade-offs in the design of TPF. The possible trade-offs include orbit location (1 to 5 AU), aperture size (6 to 1.5m), physically connected baselines or separated spacecraft flying in close formation.

Beichman, Charles

1997-01-01

167

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

168

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

169

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

170

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

171

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

Microsoft Academic Search

The Global Verification and Location System (GVLS) is a satellite based communication package proposed for the Global Positioning System (GPS) Block IIR satellites. This system provides the capability to relay bursts of information from small, low power mobile transmitters to command and control facilities. Communication paths through multiple GPS satellites within the field of view allow location of the transmitter

Kern

1994-01-01

172

Spread spectrum synchronization for a LEO personal communications satellite system  

Microsoft Academic Search

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

D. E. Dodds; M. Moher

1995-01-01

173

NASA'S communications programs - 1985  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

174

31 CFR 542.511 - Exportation of certain services incident to Internet-based communications authorized.  

...incident to Internet-based communications authorized. (a...the exchange of personal communications over the Internet, such...transmission facilities (such as satellite or terrestrial network connectivity...purposes other than personal communications (e.g.,...

2014-07-01

175

Solar terrestrial observatory  

NASA Technical Reports Server (NTRS)

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

1981-01-01

176

Overview of terrestrial thermionics  

SciTech Connect

Thermionic energy conversion addresses important national objectives such as fossil fuel conservation and space reactors. Historically, thermionics was first developed for space applications where the refractory materials required at emitter temperatures could operate indefinitely in the vacuum. Translation of this space technology to terrestrial applications required that a means of protecting the high temperature refractory metals from the air be found. A trilayer structure (tungsten emitter, silicon carbide protective layer and intermediate graphite substrate) made by chemical vapor deposition has given excellent results in combustion atmospheres.

Huffman, F.

1983-08-01

177

Antarctic terrestrial ecosystems  

SciTech Connect

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

Walton, D.W.H.

1987-01-01

178

Pose measurement of large non-cooperative satellite based on collaborative cameras  

NASA Astrophysics Data System (ADS)

In recent years some communications satellites lost their ability due to the failure of mechanisms to deploy, which resulted in large cost. A space robotic system is expected to perform the on-orbit repairing mission. This is a tremendous challenge since the targets are generally non-cooperative, i.e. no facilities used for relative state measurement are mounted on the targets. Moreover these targets are very large. Limited by the FOV (field of view), a monocular camera cannot supply enough information of the targets in close range. In this paper, a method based on two collaborative cameras is proposed to determine the pose (position and orientation) of a large non-cooperative target. Firstly, we designed a sensing system used for the non-cooperative measurement, according to the investigation of the characteristics of communications satellites. A rectangular feature, which is common in the configuration of a satellite, is chosen as the recognized object. Secondly, we proposed that two cameras share the recognition task in a collaborative behavior, i.e. each provides partial image of the rectangle, and the full feature is then obtained by fusing their information. Lastly, the corresponding algorithm of image processing and pose measurement is addressed. Simulation results of typical cases verify the proposed approach.

Du, Xiaodong; Liang, Bin; Xu, Wenfu; Qiu, Yue

2011-06-01

179

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

180

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

181

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

182

Terrestrial Planet Atmospheres and Biosignatures  

NASA Astrophysics Data System (ADS)

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

Meadows, V.; Seager, S.

183

SOLAR PHYSICS AND TERRESTRIAL EFFECTS Solar-Terrestrial Interactions  

E-print Network

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

Mojzsis, Stephen J.

184

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 cm receiver telescope on the satellite could be used to successfully perform QKD multiple times per week with either an entangled photon source or with a weak coherent pulse source, as well as perform long-distance Bell tests and quantum teleportation. Our model helps to resolve important design considerations such as operating wavelength, type and specifications of sources and detectors, telescope designs, specific orbits and ground station locations, in view of anticipated overall system performance.

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

2012-11-12

185

Global Communications Infrastructure: CTBT Treaty monitoring using space communications  

NASA Astrophysics Data System (ADS)

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

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

186

Terrestrial Coordinate Systems and Frames  

NASA Astrophysics Data System (ADS)

A terrestrial reference system (TRS) is a spatial reference system corotating with the Earth in its DIURNAL MOTION in space. In such a system, the positions of points anchored on the Earth's solid surface have coordinates which have only small variations with time, as a result of geophysical effects (tectonic or tidal deformations; see TECTONICS, EARTH'S INTERIOR, TIDES). A terrestrial reference ...

Boucher, C.; Murdin, P.

2000-11-01

187

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

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

188

Estimating the global oceanic net freshwater flux from Argo and comparing it with satellite-based freshwater flux products  

NASA Astrophysics Data System (ADS)

the idea that analysis of in situ information in the salt budget could be used as a surrogate for global "ocean rain gauge," the annual mean oceanic net freshwater flux (E-P) was estimated from the Argo profiles and the wind stress data on a global scale. The comparison between the independent E-P estimation from Argo and the E-P product sets, including the combination of precipitation from TRMM, GPCP, CMAP and evaporation from OAFlux, GSSTF3 and IFREMER and E-P set from NEWS formed from satellite, generally show similar spatial patterns, particularly on the large scale. However, there are differences among the different satellite-based E-P estimates and between satellite estimates and independent in situ estimates. Based on the pattern correlation and the RMSD, the evaporation and precipitation from OAFlux and TRMM agrees best with the E-P estimated from the independent Argo-based estimates.

Ren, Li; Hackert, Eric; Arkin, Phillip; Busalacchi, Antonio J.

2014-11-01

189

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

190

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

191

31 CFR 560.540 - Exportation of certain services and software incident to Internet-based communications.  

...incident to Internet-based communications. (a) To the extent...the exchange of personal communications over the Internet, such...transmission facilities (such as satellite or terrestrial network connectivity...purposes other than personal communications (e.g.,...

2014-07-01

192

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

193

Mobile radio alternative systems study terrestrial systems concepts  

NASA Astrophysics Data System (ADS)

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.

1983-06-01

194

Utility terrestrial biodiversity issues  

SciTech Connect

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

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

1996-11-01

195

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

196

Contaminant Exposure in Terrestrial Vertebrates  

EPA Science Inventory

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

197

Parallel Computing for Terrestrial Ecosystem Carbon Modeling  

Microsoft Academic Search

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,

Dali Wang; Wilfred M Post; Daniel M Ricciuto; Michael Berry

2011-01-01

198

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

199

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

200

int. j. remote sensing, 2000, vol. 21, no. 16, 30713082 Satellite-based mapping of Canadian boreal forest res: evaluation and  

E-print Network

boreal forest were created by composit- ing the daily maps of re hot spots over the summerint. j. remote sensing, 2000, vol. 21, no. 16, 3071­3082 Satellite-based mapping of Canadian boreal is capable of detecting the majority of res over the boreal forest, but also includes many false res over old

Li, Zhanqing

201

Supplemental*information*for*"SPARTAN:*A*Global*Network*to*Evaluate*1 and*Enhance*Satellite?Based*Estimates*of*Ground?level*Particulate*Matter*2  

E-print Network

*Enhance*Satellite?Based*Estimates*of*Ground?level*Particulate*Matter*2 for*Global*Health*Applications"*3 4 S1 Evaluation*of*SPARTAN*sampling*strategy**5 6 S1.1 Losses*of*Aerosol*Ammonium*Nitrate*7 8 Ammonium nitrate (ANO3) PM2.5 was generated with a mean diameter of 400 nm9 using a TSI Constant

Martin, Randall

202

Optimal Estimates of Global Terrestrial GPP from Fluorescence and DGVMs  

NASA Astrophysics Data System (ADS)

Changes in the processes that control terrestrial carbon uptake are highly uncertain but likely to have a significant influence on future atmospheric CO2 levels. RECCAP aims to improve process understanding by reconciling fluxes from top-down CO2 inversions and bottom-up estimates from an ensemble of DGVMs. As these models are typically used in projections of climate change a key part of this effort is benchmarking models and evaluating drivers of net carbon exchange within the current climate. Of particular importance are the spatial distribution and time rate of change of GPP. Recent advances in the remote sensing of solar-induced chlorophyll fluorescence opens up a new possibility to directly measure planetary photosynthesis on spatially resolved scales. Here, we discuss a new methodology for estimating GPP and uncertainty from an optimal combination of an ensemble of DGVMs from the TRENDY project with satellite-based fluorescence observations from GOSAT. Prior uncertainty is estimated from the spread of DGVMs and updated through assimilation of fluorescence. We evaluate optimized fluxes against flux tower data in N. America, Europe, and S. America, benchmark TRENDY models using updated uncertainty estimates, and examine changes in the structure of the seasonal cycle. We find this methodology provides a novel way to evaluate models used in climate projections.

Parazoo, Nicholas; Bowman, Kevin; Fisher, Joshua; Frankenberg, Christian; Jones, Dylan; Cescatti, Alessandro; Perez-Priego, Oscar; Wohlfahrt, Georg; Montagnani, Leonardo

2014-05-01

203

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

204

Comparison of ocean surface solar irradiance in the GLA General Circulation Model and satellite-based calculations  

SciTech Connect

A global, 7-year satellite-based record of ocean surface solar irradiance (SSI) is used to assess the realism of ocean SSI simulated by the nine-layer Goddard Laboratory for Atmospheres (GLA) General Circulation Model (GCM). January and July climatologies of net SSI produced by the model are compared with corresponding satellite climatologies for the world oceans between 54[degrees]N and 54[degrees]S. This comparison of climatologies indicates areas of strengths and weaknesses in the GCM treatment of cloud-radiation interactions, the major source of model uncertainty. Realism of ocean SSI is also important for applications such as incorporating the GLA GCM into a coupled ocean-atmosphere GCM. The results show that the GLA GCM simulates too much SSI in the extratropics and too little in the tropics, especially in the summer hemisphere. These discrepancies reach magnitudes of 60 W m[sup [minus]2] and more. The discrepancies are particularly large in the July case off the western coast of North America. In this region of persistent marine stratus, the GCM climatological values exceed the satellite climatological values by as much as 131 W m[sup [minus]2]. Positive and negative discrepancies in SSI are shown to be consistent with discrepancies in planetary albedo.

Chertock, B. (NOAA/Environmental Research Laboratories, Boulder, CO (United States)); Sud, Y.C. (NASA/Goddard Space Flight Center, Greenbelt, MD (United States))

1993-03-01

205

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

NASA Astrophysics Data System (ADS)

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

Kaneko, Daijiro

2013-10-01

206

Assessing the performance of satellite-based precipitation products and its dependence on topography over Poyang Lake basin  

NASA Astrophysics Data System (ADS)

Satellite-based precipitation products (SPPs) have greatly improved their applicability and are expected to offer an alternative to ground-based precipitation estimates in the present and the foreseeable future. There is a strong need for a quantitative evaluation of the usefulness and limitations of SPPs in operational meteorology and hydrology. This study compared two widely used high-resolution SPPs, the Tropical Rainfall Measuring Mission (TRMM) and Precipitation Estimation from Remote Sensing Information using Artificial Neural Network (PERSIANN) in Poyang Lake basin which is located in the middle reach of the Yangtze River in China. The bias of rainfall amount and occurrence frequency under different rainfall intensities and the dependence of SPPs performance on elevation and slope were investigated using different statistical indices. The results revealed that (1) TRMM 3B42 usually underestimates the rainy days and overestimates the average rainfall as well as annual rainfall, while the PERSIANN data were markedly lower than rain gauge data; (2) the rainfall contribution rates were underestimated by TRMM 3B42 in the middle rainfall class but overestimated in the heavy rainfall class, while the opposite trend was observed for PERSIANN; (3) although the temporal distribution characteristics of monthly rainfall were correctly described by both SPPs, PERSIANN tended to suffer a systematic underestimation of rainfall in every month; and (4) the performances of both SPPs had clear dependence on elevation and slope, and their relationships can be fitted using quadratic equations.

Li, Xianghu; Zhang, Qi; Xu, Chong-Yu

2014-02-01

207

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

208

Digital communications: Satellite\\/earth station engineering  

Microsoft Academic Search

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

K. Feher

1983-01-01

209

A satellite system for land-mobile communications in Europe  

NASA Technical Reports Server (NTRS)

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

Bartholome, P.; Rogard, R.

1988-01-01

210

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

211

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

212

Observing terrestrial gamma ray flashes  

NASA Astrophysics Data System (ADS)

Terrestrial Gamma Ray Flash Workshop; Huntsville, Alabama, 13-14 July 2011 Terrestrial gamma ray flashes (TGFs) were the focus of a workshop held at the University of Alabama in Huntsville (UAH), with observation and theory well represented by the 38 attendees. Discovered in 1991 as brief (submillisecond), bright flashes of gamma rays detected over regions of thunderstorm activity by the spaceborne Burst And Transient Source Experiment, TGFs may be entering an observational golden era. Three space-based gamma ray telescopes currently make TGFs a scientific priority.

Connaughton, Valerie; Briggs, Michael S.

2011-12-01

213

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

214

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

215

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

SciTech Connect

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

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

2014-04-09

216

Development of satellite-based high-resolution ensemble forcing fields for hydrologic modeling using a data assimilation framework  

NASA Astrophysics Data System (ADS)

In spatially-distributed land surface modeling applications the forcing fields, most notably radiation and precipitation, exert a significant control on the space/time variability of the resulting land surface states (e.g. soil moisture and temperature) and fluxes (e.g. evapotranspiration and runoff). In most regions of the globe the in-situ networks for accurately estimating these forcing fields are of inadequate density. Furthermore, uncertainty in these inputs directly propagates to the land surface predictions. To take advantage of the multitude of spatially-distributed satellite data related to these fluxes, many retrieval methods have been developed to estimate some of these forcing fields. However while satellite data and the resulting products provide the potential for global coverage, weaknesses still exist including inadequate spatial/temporal resolution and/or sampling and other inaccuracies. In this study we attempt to develop a general data assimilation framework that is capable of yielding ensemble surface forcing fields that are i) physically consistent (coupled) ii) at high spatial/temporal resolution, iii) a merged estimate based on multi-scale satellite inputs, and iv) reflective of the uncertainty contained in the various satellite-based input data streams. The framework uses high-resolution cloud characteristics obtained from geostationary satellites to couple parsimonious radiation and precipitation models used to generate ensemble a priori estimates. These prior fields can then be merged with other products (using a data assimilation approach) to yield the final a posteriori estimates with the characteristics mentioned above. Results will be presented from an application over a regional domain in the Midwestern U.S. We hypothesize that using these forcing fields in hydrologic models will yield improved estimates of both the mean hydrologic states/fluxes and their uncertainty. Future work will test this hypothesis.

Margulis, S. A.

2008-12-01

217

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

218

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

219

Emergency Communication for Electric Power System Based on Airship  

Microsoft Academic Search

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

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

2009-01-01

220

PROPULSION AND ENERGY Terrestrial energy  

E-print Network

PROPULSION AND ENERGY Terrestrial energy On the morning of Monday, August 29, Hurri- cane Katrina, hydro, and nuclear, have not come to the forefront, and what can be done to remedy this situation, nuclear, solar, and geothermal energy. New initiatives by the Dept. of Energy are focusing

Aggarwal, Suresh K.

221

The Terrestrial Planets Large Bodies  

E-print Network

: Greenhouse Effect: Solar heating & atmospheric cooling balance Helps determine if H2O is liquid, ice atmosphere. May have had early oceans that evaporated resulting in a Runaway Greenhouse Effect. Gravity elements. #12;The evolution of Terrestrial Planet atmospheres is driven by three primary effects

Gaudi, B. Scott

222

Scientist Using Terrestrial Lidar Equipment  

USGS Multimedia Gallery

Chris Soulard using the Terrestrial Lidar to scan study area in the Grand Canyon-Parashant National Monument, AZ.  Note the bag of ice on the equipment.  High temperates can cause equipment to overheat, requiring scientists to be creative in protecting equipment....

223

Measurement of Terrestrial Radio Noise  

Microsoft Academic Search

The terrestrial noise experiment on the Ariel III satellite is designed to measure the radio noise from lighting discharges, and to deduce the distribution of the sources. The measurements are made at high frequencies; at optimum frequencies the noise penetrates the ionosphere only at near vertical incidence and the sources can therefore be localized. The receivers operate in narrow bandwidths

F. Horner; R. B. Bent

1969-01-01

224

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

225

Terrestrial heat flow in Cuba  

NASA Astrophysics Data System (ADS)

The results of two joint expeditions to Cuba to measure terrestrial heat flow in 1983 and 1986 are summarized. Twenty-three new values are presented, which confirm the low heat flow in practically all of the island. The mean and standard deviation (44.7 ± 13.4 mW m -2) agree well with previous observations.

?ermák, V.; Krešl, M.; Šafanda, J.; Bodri, L.; Nápoles-Pruna, M.; Tenreyro-Perez, R.

226

Economic-Analysis Program for a Communication System  

NASA Technical Reports Server (NTRS)

Prices and profits of alternative designs compared. Objective of Land Mobile Satellite Service Finance Report (LMSS) program is to provide means for comparing alternative designs of LMSS systems. Program is Multiplan worksheet program. Labels used in worksheet chosen for satellite-based cellular communication service, but analysis not restricted to such cases. LMSS written for interactive execution with Multiplan (version 1.2) and implemented on IBM PC series computer operating under DOS (version 2.11).

Chamberlain, R. G.

1986-01-01

227

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

228

Study terrestrial applications of solar cell powered systems  

NASA Technical Reports Server (NTRS)

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

Ravin, J. W.

1973-01-01

229

Terrestrial biogeochemical feedbacks in the climate system  

Microsoft Academic Search

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

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

2010-01-01

230

The Economic Potential of Terrestrial Impact Craters  

Microsoft Academic Search

Like concentrations of economic resources, terrestrial impact structures are the result of relatively rare geologic events. Economic resources occur in a number of terrestrial impact structures. After providing a context by briefly summarizing the salient points of the terrestrial impact record and the characteristics of impact craters, the relationship between impact craters and economic resources is explored. Approximately 25% of

R. A. F. Grieve; V. L. Masaitis

1994-01-01

231

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

PubMed Central

Satellite-based PM2.5 monitoring has the potential to complement ground PM2.5 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 PM2.5 concentrations. However, previous studies have shown that AOD may not be a strong predictor of PM2.5 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 PM2.5 concentrations. First, we render AOD a robust predictor of PM2.5 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 PM2.5 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 PM2.5 concentrations for both retrieval days (i.e., days with satellite data available) and non-retrieval days in the New England region of the U.S. during the period 2000-2008. Overall, for the years 2000-2008, our statistical models predicted surface PM2.5 concentrations with reasonably high R2 (0.83) and low percent mean relative error (3.5%). Also the spatial distribution of the estimated PM2.5 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

2012-01-01

232

Intraspecific Communication Communication  

E-print Network

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

Dever, Jennifer A.

233

Arsenic Speciation of Terrestrial Invertebrates  

SciTech Connect

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

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

2009-07-01

234

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

E-print Network

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

Peale, Robert E.

235

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

236

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

237

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

NASA Astrophysics Data System (ADS)

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

Dashora, Nirvikar

2012-07-01

238

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

239

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

PubMed

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

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

2014-01-01

240

Terrestrial mobile communication train measurements in western India  

Microsoft Academic Search

Mobile train radio measurements were conducted in the UHF band in western India with a total distance of 140 km utilizing eight track side base stations in different environments. The observed path losses deduced from signal levels were compared with those deduced from several prediction methods and their standard deviations are discussed. Path loss exponents are derived from signal levels

M. V. S. N. Prasad; Rajendra Singh

2003-01-01

241

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

242

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

243

COMMUNICATIONS ANNEX B -COMMUNICATIONS  

E-print Network

and interoperable communications systems are essential to obtain the most complete information during emergency should an event or incident warrant the need for increased interoperable communications; however, their primary channels are on the 800 MHz system. o Environmental Health and Safety o Facilities Services o

244

Communication section Communication section  

E-print Network

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

Richner, Heinz

245

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

246

V. Rao & G. Lachapelle, NAVCOM 2012 Pearl Jubilee International Conference on Navigation and Communication, Hyderabad, India, 20-21 December 2012 Page 1 of 4  

E-print Network

and Communication, Hyderabad, India, 20-21 December 2012 Page 1 of 4 Proposed Third Frequency of Operation for IRNSS frequency of operation is proposed for IRNSS over the Indian subcontinent. Satellite Based Augmentation is the ionosphere. Extending the benefits of DGPS, SBAS became an alternative from a global perspective. Apart from

Calgary, University of

247

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

248

Love numbers of the terrestrial planets  

Microsoft Academic Search

The latest geodetic parameters of the terrestrial planets are used to construct parametric models of the internal structure of the terrestrial planets. These models are then used to compute the static Love numbers from order 2 to 30. The influence of the outer core rigidity on the second-order Love numbers is discussed. The obtained results indicate that the probable ranges

Cheng-Zhi Zhang

1991-01-01

249

Love numbers of the terrestrial planets  

Microsoft Academic Search

Using the latest geodetic parameters of the terrestrial planets, the author constructed the parametric models of the internal structure of the terrestrial planets. By means of these models he computed their static Love numbers from order 2 to 30 and listed the results. Then he discussed the influence of the outer core rigidity on the second-order Love numbers.

Zhangzhi Cheng

1991-01-01

250

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

251

Terrestrial Mammals of the Riparian Corridor  

E-print Network

Terrestrial Mammals of the Riparian Corridor in Big Bend National Park1 William J. Boeer and David J. Schmidly2 Abstract.--Thirty species of terrestrial mammals inhabit riparian habitats in Big and Peromyscus leucopus). Compared to the other major plant communities in BBNP, the rodent fauna of the riparian

252

Terrestrial Ages of Antarctic Meteorites- Update 1999  

NASA Technical Reports Server (NTRS)

We are continuing our ongoing study of cosmogenic nuclides in Antarctic meteorites. In addition to the studies of exposure histories of meteorites, we study terrestrial ages and pairing of Antarctic meteorites and desert meteorites. Terrestrial ages of Antarctic meteorites provide information on meteorite accumulation mechanisms, mean weathering lifetimes, and influx rates. The determination of Cl-36(half-life=3.01 x 10(exp 5) y) terrestrial ages is one of our long-term on-going projects, however, in many instances neither Cl-36 or C-14 (5,730 y) yields an accurate terrestrial age. Using Ca-14 (1.04 x 10(exp 5) y) for terrestrial age determinations solves this problem by filling the c,ap in half-life between 14-C and Cl-36 ages. We are now applying the new Ca-41- Cl-36 terrestrial age method as well as the Cl-36-Be-10 method to Antarctic meteorites. Our measurements and C-14 terrestrial age determinations by the University of Arizona group are always complementary. We have measured Cl-36 in over 270 Antarctic meteorites since our previous compilation of terrestrial ages. Since a large number of meteorites have been recovered from many different icefields in Antarctica, we continue to survey the trends of terrestrial ages for different icefields. We have also measured detailed terrestrial ages vs. sample locations for Allan Hills, Elephant Moraine, and Lewis Cliff Icefields, where meteorites have been found with very long ages. The updated histograms of terrestrial ages of meteorites from the Allan Hills Main Icefield and Lewis Cliff Icefield are shown. These figures include C-14 ages obtained by the University of Arizona group. Pairs of meteorites are shown as one object for which the age is the average of all members of the same fall. The width of the bars represents 70,000 years, which was a typical uncertainty for Cl-36 ages. We reduced the uncertainty of terrestrial age determinations to approx. 40,000 years by using pairs of nuclides such as Ca-41-Cl-36 or Cl-36-Be-10. Meteorites found at the Allan Hills Icefields are much older than any other meteorites. The terrestrial ages cover a wide range and are as old as 2 My. Many of the Lewis Cliff meteorites are as old as the Allan Hills meteorites. So far, no clear correlation has been found between the terrestrial ages and the locations of the Lewis Cliff meteorites.

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

1999-01-01

253

Project Universe - Local area networks and satellite communications  

Microsoft Academic Search

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

B. R. Ackroyd

1983-01-01

254

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

255

Methane production in terrestrial arthropods  

SciTech Connect

The authors 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. The authors show that arthropod symbionts can contribute substantially to atmospheric methane.

Hackstein, J.H.P.; Stumm, C.K. (Catholic Univ. of Nijmegen (Netherlands))

1994-06-07

256

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

257

Terrestrial gamma-ray flashes  

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

258

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

259

Steroidal glycosides from Tribulus terrestris  

Microsoft Academic Search

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

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

1996-01-01

260

Contrasting coloration in terrestrial mammals  

PubMed Central

Here I survey, collate and synthesize contrasting coloration in 5000 species of terrestrial mammals focusing on black and white pelage. After briefly reviewing alternative functional hypotheses for coloration in mammals, I examine nine colour patterns and combinations on different areas of the body and for each mammalian taxon to try to identify the most likely evolutionary drivers of contrasting coloration. Aposematism and perhaps conspecific signalling are the most consistent explanations for black and white pelage in mammals; background matching may explain white pelage. Evidence for contrasting coloration is being involved in crypsis through pattern blending, disruptive coloration or serving other functions, such as signalling dominance, lures, reducing eye glare or in temperature regulation has barely moved beyond anecdotal stages of investigation. Sexual dichromatism is limited in this taxon and its basis is unclear. Astonishingly, the functional significance of pelage coloration in most large charismatic black and white mammals that were new to science 150 years ago still remains a mystery. PMID:18990666

Caro, Tim

2008-01-01

261

A Spherical Aerial Terrestrial Robot  

NASA Astrophysics Data System (ADS)

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

Dudley, Christopher J.

262

Sharing Resources In Mobile/Satellite Communications  

NASA Technical Reports Server (NTRS)

Report presents preliminary theoretical analysis of several alternative schemes for allocation of satellite resource among terrestrial subscribers of landmobile/satellite communication system. Demand-access and random-access approaches under code-division and frequency-division concepts compared.

Yan, Tsun-Yee; Sue, Miles K.

1992-01-01

263

Spread spectrum access methods for wireless communications  

Microsoft Academic Search

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

Ryuji Kohno; Reuven Meidan; Laurence B. Milstein

1995-01-01

264

Satellite Communication.  

ERIC Educational Resources Information Center

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

Technology Teacher, 1985

1985-01-01

265

Introduction Multiple lineages of terrestrial vertebrates, including frogs,  

E-print Network

3358 Introduction Multiple lineages of terrestrial vertebrates, including frogs, snakes, lizards crossing a large gap between trees Among terrestrial vertebrate gliders, take-off presents a unique problem

Socha, Jake

266

Integrated Estimates of Global Terrestrial Carbon Sequestration  

SciTech Connect

Assessing the contribution of terrestrial carbon sequestration to international climate change mitigation requires integration across scientific and disciplinary boundaries. As part of a scenario analysis for the US Climate Change Technology Program, measurements and geographic data were used to develop terrestrial carbon sequestration estimates for agricultural soil carbon, reforestation and pasture management. These estimates were then applied in the MiniCAM integrated assessment model to evaluate mitigation strategies within policy and technology scenarios aimed at achieving atmospheric CO2 stabilization by 2100. Adoption of terrestrial sequestration practices is based on competition for land and economic markets for carbon. Terrestrial sequestration reach a peak combined rate of 0.5 to 0.7 Gt carbon yr-1 in mid-century with contributions from agricultural soil (0.21 Gt carbon yr-1), reforestation (0.31 Gt carbon yr-1) and pasture (0.15 Gt carbon yr-1). Sequestration rates vary over time period and with different technology and policy scenarios. The combined contribution of terrestrial sequestration over the next century ranges from 31 to 41 GtC. The contribution of terrestrial sequestration to mitigation is highest early in the century, reaching up to 20% of total carbon mitigation. This analysis provides insight into the behavior of terrestrial carbon mitigation options in the presence and absence of climate change mitigation policies.

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

2008-02-01

267

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

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

268

Frequency allocation problem in a SDMA satellite communication system Laurent Houssin12  

E-print Network

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

Paris-Sud XI, Université de

269

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

SciTech Connect

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

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

2014-05-06

270

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

271

The initial IERS Terrestrial Reference Frame.  

NASA Astrophysics Data System (ADS)

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

Boucher, C.; Altamimi, Z.

1989-06-01

272

Solar-terrestrial models and application software  

NASA Technical Reports Server (NTRS)

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

Bilitza, Dieter

1990-01-01

273

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

274

Earth and Terrestrial Planet Formation  

E-print Network

The growth and composition of Earth is a direct consequence of planet formation throughout the Solar System. We discuss the known history of the Solar System, the proposed stages of growth and how the early stages of planet formation may be dominated by pebble growth processes. Pebbles are small bodies whose strong interactions with the nebula gas lead to remarkable new accretion mechanisms for the formation of planetesimals and the growth of planetary embryos. Many of the popular models for the later stages of planet formation are presented. The classical models with the giant planets on fixed orbits are not consistent with the known history of the Solar System, fail to create a high Earth/Mars mass ratio, and, in many cases, are also internally inconsistent. The successful Grand Tack model creates a small Mars, a wet Earth, a realistic asteroid belt and the mass-orbit structure of the terrestrial planets. In the Grand Tack scenario, growth curves for Earth most closely match a Weibull model. The feeding zon...

Jacobson, Seth A

2015-01-01

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

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

277

End-to-end network modeling and simulation of integrated terrestrial, airborne and space environments  

Microsoft Academic Search

Northrop Grumman Information Technology (IT) TASC has developed a comprehensive modeling, simulation and visualization capability that includes space, airborne, and terrestrial environments to support the analysis of mission driven end-to-end communications solutions for intelligence, military operations, homeland security, and other needs from the government or commercial sectors. The end-to-end network modeling (EENM) and simulation capability includes all layers of the

Lawrence Baranyai; Enrique G. Cuevas; Scott Davidow; Christopher Demaree; Paul DiCaprio

2005-01-01

278

The Network Packing Problem in Terrestrial Broadcasting  

E-print Network

In the context of terrestrial video broadcasting, digital technology most likely will re- ... and to the scarce penetration of cable and satellite networks, the Italian context ..... This requirement can be expressed by the following set of constraints: µ.

2005-03-03

279

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

280

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...

281

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

282

Space Vehicle Terrestrial Environment Design Requirements Guidelines  

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

283

aborate communicate aborate communicate  

E-print Network

, pharmaceuticals, food and agricultural production, advance polymeric and electronic materials, energy production, Aerospace, Manufacturing, Mechatronics, Energy and Fluid Systems. Many students choose not to specialize The information and communications technology of our knowledge-based society places computer engineers at the hub

Graham, Nick

284

Communicating About Communicable Disease  

NSDL National Science Digital Library

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

IBM& #39; s Teachers Try Science program

2011-11-23

285

Global Change and the Terrestrial Biosphere  

SciTech Connect

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

Alistair Rogers

2009-04-22

286

The NASA-Lewis terrestrial photovoltaics program  

NASA Technical Reports Server (NTRS)

Those parts of the present NASA-Lewis research and technology effort on solar cells and arrays having relevance to terrestrial uses are outlined. These include raising cell efficiency, developing the FEP-covered module concept, and exploring low-cost cell concepts. Solar cell-battery power systems for remote weather stations have been built to demonstrate the capabilities of solar cells for terrestrial applications.

Bernatowicz, D. T.

1974-01-01

287

Possible climates on terrestrial exoplanets.  

PubMed

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

Forget, F; Leconte, J

2014-04-28

288

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

E-print Network

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

Koptur, Suzanne

289

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

290

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

291

Terrestrial teleconnections link global rivers  

NASA Astrophysics Data System (ADS)

We present analyses of river discharge data from across the world, which we used to identify links between annual river flow regimes across different continents. Our hypothesis was that, as atmospheric processes are subject to large-scale teleconnection patterns, and because these atmospheric processes are inherently linked to precipitation regimes across the world, there should be identifiable links between river flow regimes driven by these atmospheric processes. We used discharge data from the Global Runoff Data Centre (GRDC) to identify cross-correlations (and accounted for serial dependence) between 23 of the world's largest river basins where overlapping data were available over a period of 12 years or more: two in South America; five in Africa; one in Australasia; five in North America and ten in Eurasia. The selected river basins drain approximately a third of the Earth's landmass at their furthest downstream gauging station. Where significant cross-correlations were found, we compared these to known patterns associated with the ENSO and NAO teleconnections. In total, 85 of the 253 possible correlations were deemed significant at p<0.05, this reduced to 36 at p<0.01 and 21 at p<0.001. Of the significant correlations (p<0.05), 22 were classified as strong (r ?× 0.5), 45 as moderate (×0.5< r ?×0.25) and 18 as weak (×0.25< r >0). We compared these significant cross-correlations with known atmospheric teleconnection patterns, and while these were consistent for the majority of cases, we found a number of significant correlations that are inconsistent with the anticipated effects of known atmospheric teleconnections. Our results provide new insight into the inter-continental links between global river systems and the way in which these are controlled by large-scale atmospheric processes. We suggest this may be useful for global industries, such as insurers or aid agencies, who seek to understand correlations between the magnitudes of extreme events across different regions of the world. For the former, this may enable more efficient management of global liabilities, for the latter it may enable better logistical planning of disaster relief requirements. Aside from these practical applications, the results also suggest teleconnections exist between terrestrial, as well as ocean and atmospheric water systems.

O'Loughlin, F.; Howden, N. J.; Woods, R. A.; Bates, P. D.

2013-12-01

292

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

293

Transmission Communication  

E-print Network

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

Chen, Sheng

294

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

295

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.

0000-00-00

296

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

297

Planetary geology and terrestrial analogs in Asia  

NASA Astrophysics Data System (ADS)

2011 PERC Planetary Geology Field Symposium;Kitakyushu City, Japan, 5-6 November 2011 In spite of the extremely diverse geological settings that exist in Asia, relatively little attention has previously been paid to this region in terms of terrestrial analog studies for planetary application. Asia is emerging as a major center of studies in planetary geology, but no attempt had been made in the past to organize a broadly based meeting that would allow planetary geologists in Asia to meet with ones from more advanced centers, such as the United States and Europe, and that would include the participation of many geologists working primarily on terrestrial research. The Planetary Exploration Research Center (PERC) of the Chiba Institute of Technology hosted the first planetary geology field symposium in Asia to present results from recent planetary geology studies and to exchange ideas regarding terrestrial analogs (http://www.perc.it-chiba.ac.jp/meetings/pgfs2011/index.html).

Komatsu, Goro; Namiki, Noriyuki

2012-04-01

298

Comparative planetology: Significance for terrestrial geology  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

299

Effective extensions of Internet in hybrid satellite-terrestrial networks  

NASA Astrophysics Data System (ADS)

DirecPCTM's Turbo Internet is a low-cost hybrid (satellite-terrestrial) high-speed digital transmission system developed as a collaborative effort between the Center for Satellite and Hybrid Communication Networks and Hughes Network Systems. The system uses receive-only VSAT satellite links for downstream data delivery and public telephone networks at modem speeds to provide the upstream communications path. One of the services provided is high speed Internet access based on an asymmetric TCP/IP protocol. In the initial protocol implementation, we achieved four times higher throughput than that of today high-speed modems (28.8 Kbps) alone (Falk 1995). This throughput can be further enhanced. The mismatch in bandwidth and delay in this hybrid network prevents the full use of the satellite link bandwidth (1 Mbps). This paper presents two techniques, TCP spoofing and selective acknowledgment dropping, which significantly increase the overall throughput of the hybrid network. Our approach does not require any modification to the TCP/IP protocol stacks on the end hosts. The solutions proposed in this paper could be used to improve TCP/IP performance of other hybrid networks which have the disadvantage of high bandwidth-delay products and/or low bandwidth return paths.

Arora, Vivek; Suphasindhu, Narin; Baras, John S.; Dillon, Douglas

1996-03-01

300

Army Space Systems For Terrestrial Applications  

NASA Astrophysics Data System (ADS)

Army combat forces involved in global military operations require knowledge of the terrain and accurate positioning and navigation capability to effectively perform their missions. Combat critical data from satellite-based systems to augment ground and airborne data collection, processing, and dissemination systems are crucial for the delivery and use of the needed information and intelligence in near-real time. The Army is developing ground-based testbed systems to utilize terrain and weather data collected from space-based platforms to enhance Army commanders' battlefield capabilities, and is researching new applications for the NAVSAT Global Positioning System and the Defense Advanced Research Projects Agency-sponsored (DARPA) LIGHTSAT program that are unique to the Army. In addition, the Army is designing experiments to be conducted on the Space Shuttle.

Dickerman, Ronald L.; Gomez, Richard B.

1988-04-01

301

Magnetic fields of the terrestrial planets  

NASA Technical Reports Server (NTRS)

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

Russell, C. T.

1993-01-01

302

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

303

Cultural Communications.  

ERIC Educational Resources Information Center

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

Armas, Jose

304

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

305

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

306

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

307

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

308

Characterization of Neutral Lipase BT-1 Isolated from the Labial Gland of Bombus terrestris Males  

PubMed Central

Background In addition to their general role in the hydrolysis of storage lipids, bumblebee lipases can participate in the biosynthesis of fatty acids that serve as precursors of pheromones used for sexual communication. Results We studied the temporal dynamics of lipolytic activity in crude extracts from the cephalic part of Bombus terrestris labial glands. Extracts from 3-day-old males displayed the highest lipolytic activity. The highest lipase gene expression level was observed in freshly emerged bumblebees, and both gene expression and lipase activity were lower in bumblebees older than 3 days. Lipase was purified from labial glands, further characterized and named as BT-1. The B. terrestris orthologue shares 88% sequence identity with B. impatiens lipase HA. The molecular weight of B. terrestris lipase BT-1 was approximately 30 kDa, the pH optimum was 8.3, and the temperature optimum was 50°C. Lipase BT-1 showed a notable preference for C8-C10 p-nitrophenyl esters, with the highest activity toward p-nitrophenyl caprylate (C8). The Michaelis constant (Km) and maximum reaction rate (Vmax) for p-nitrophenyl laurate hydrolysis were Km = 0.0011 mM and Vmax = 0.15 U/mg. Conclusion This is the first report describing neutral lipase from the labial gland of B. terrestris. Our findings help increase understanding of its possible function in the labial gland. PMID:24260337

Brabcová, Jana; Prchalová, Darina; Demianová, Zuzana; Bu?ánková, Alena; Vogel, Heiko; Valterová, Irena; Pichová, Iva; Zarevúcka, Marie

2013-01-01

309

INMARSAT's personal communicator system  

NASA Astrophysics Data System (ADS)

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

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

310

INMARSAT's personal communicator system  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

311

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

NASA Astrophysics Data System (ADS)

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

Mecikalski, John; Smith, Tracy; Weygandt, Stephen

2014-05-01

312

MICROBIAL ECOLOGY OF THE TERRESTRIAL SUBSURFACE  

EPA Science Inventory

A current view is presented of the microbial ecology of the terrestrial subsurface by considering primarily the ecology of shallow aquifer sediments. The properties of the aquifer sediments and groundwater determine their ability to support microbial life and control the abundanc...

313

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

314

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.

1993-01-01

315

SETI [Search for ExtraTerrestrial Intelligence  

Microsoft Academic Search

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

B. M. Oliver

1994-01-01

316

Trophic polymorphism in a terrestrial salamander  

Microsoft Academic Search

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

John C. Maerz; Erin M. Myers

2006-01-01

317

Resonant Mechanism of Solar-Terrestrial Relationships  

Microsoft Academic Search

The present paper studies the resonant mechanism of solar-terrestrial relationships and their influence on the state of individual systems of the human organism. The level of statistical correlation between the characteristics of the human cardiovascular system and the brain activity and the fundamental modes of circumterrestrial resonators are numerically evaluated.

A. G. Kolesnik; A. S. Borodin; S. A. Kolesnik; S. V. Pobachenko

2003-01-01

318

Dinosaurs and the Cretaceous Terrestrial Revolution  

E-print Network

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

Benton, Michael

319

Research in solar-terrestrial physics  

NASA Astrophysics Data System (ADS)

A report on research in solar-terrestrial physics includes the following: Ultra Low Frequency Waves; Magnetic Pulsations; Predicting Geomagnetic Activity Using Solar Wind Data; Auroral Electrojets; Partial Ring Current; The Symmetric Ring Current; The Role of Driven and Unloading Processes in Substorms; A Study of the Near-Earth Plasma Sheet; and Methods of Time Series Data Base Management.

1986-01-01

320

Saponins in Tribulus terrestris – Chemistry and Bioactivity  

Microsoft Academic Search

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

I. Kostova; D. Dinchev

2005-01-01

321

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

322

High efficiency, long life terrestrial solar panel  

Microsoft Academic Search

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

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

1977-01-01

323

Widespread genetic exchange among terrestrial bacteriophages  

E-print Network

Widespread genetic exchange among terrestrial bacteriophages Olin K. Silander*§ , Daniel M October 27, 2005 (received for review April 15, 2005) Bacteriophages are the most numerous entities Microbes are the most numerous entities in the biosphere, and viruses that infect bacteria (bacteriophages

Hartl, Daniel L.

324

Two new terrestrial Enchytraeus species (Oligochaeta, Annelida)  

Microsoft Academic Search

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

W. Westheide; U. Graefe

1992-01-01

325

Terrestrial solar cells —present and future  

Microsoft Academic Search

In this paper the principles of operation of various types of solar cell are described. Progress in photovoltaics is traced through the development of the monocrystalline silicon cell for space applications where the emphasis is upon reliability and power\\/weight ratio, to terrestrial cells where the emphasis is upon low-cost production. The role of other contenders such as polycrystalline silicon, amorphous

B. T. Debney; J. R. Knight

1978-01-01

326

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

327

DISS. ETH NO. 17036 Calibration of a Terrestrial Laser Scanner  

E-print Network

DISS. ETH NO. 17036 Calibration of a Terrestrial Laser Scanner for Engineering Geodesy For several years now, terrestrial laser scanning has become an additional surveying technique in geodesy heritage, reverse engineering, and engineering geodesy. Due to the increased requirements regarding

Giger, Christine

328

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

329

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

330

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

331

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

332

Terrestrial Sea Ice Morphology: Considerations for Europa  

NASA Astrophysics Data System (ADS)

The Galileo mission has returned the first high-resolution (21 m/pixel) images of the surface of Europa. These images reveal structures with morphologies reminiscent of those seen on terrestrial sea ice. Although it is premature to make one-to-one analogies between sea ice and Europa's surface, a review of the types of surface features commonly formed on Earth and of various sea-ice processes can provide insight into the complex geology of Europa. For example, deformation of terrestrial sea ice results from winds, tides, and currents and from thermally induced stresses; the resulting features include fractures ranging in width from millimeters to kilometers, pressure ridges, shear ridges, and rafted ice. Potential agents of deformation on Europa are more likely to be limited to tidal flexing and possibly convection, but could produce similar features and perhaps account for the ridges and fractures seen in many areas. Subtle differences in albedo and color in terrestrial sea ice result from differences in ice thickness and grain size, attributed to factors such as the rate of ice-crystal growth, water turbulence, age of the ice, and deformation. Similar factors could account for differences observed in the bright icy plains of Europa. Moreover, salts in both the solid form and as brine vary in concentration and composition as a function of space and time on Earth, leading to differences in density and the strength of ice sheets. Salts are also suspected in the europan ice and could lead to similar differences, enhancing the creation of topographic relief from density contrasts and the formation of fractures from brittle failure of the ice. Differences in the environments between Europa and terrestrial sea ice in terms of parameters such as temperature, gravity, time, and ice compositions suggest caution in drawing direct analogies. Future work by the planetary and sea-ice communities must include understanding the terrestrial processes sufficiently for extrapolation to Europa.

Greeley, Ronald; Sullivan, Robert; Coon, Max D.; Geissler, Paul E.; Tufts, B. Randall; Head, James W.; Pappalardo, Robert T.; Moore, Jeffrey M.

1998-09-01

333

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

334

A combined terrestrial reference frame based on space geodesy.  

NASA Astrophysics Data System (ADS)

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

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

1989-06-01

335

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

336

Linking Terrestrial and Marine Conservation Planning and Threats Analysis  

Microsoft Academic Search

The existence of the Gulf of Mexico dead zone makes it clear that marine ecosystems can be damaged by terrestrial inputs. Marine and terrestrial conservation planning need to be aligned in an explicit fashion to fully represent threats to marine systems. To integrate conservation planning for terrestrial and marine systems, we used a novel threats assessment that included 5 cross-system

HEATHER TALLIS; ZACH FERDAÑA; ELIZABETH GRAY

2008-01-01

337

A forecast of broadcast satellite communications  

NASA Technical Reports Server (NTRS)

This paper presents forecasts of likely changes in broadcast satellite technology, the technology of ground terminals, and the technology of terrestrial communications competitive with satellites. The impacts of these changes in technology are then assessed, using a cross-impact model of U.S. domestic telecommunications, to determine the consequences of various possible changes in communications satellite technology. These consequences are discussed in terms of various possible services, for households, businesses, and specialized customers, which might become economically viable as a result of improvements in satellite technology.

Martino, J. P.; Lenz, R. C., Jr.

1977-01-01

338

A software solution to enable roaming between satellite and terrestrial 3G networks  

NASA Astrophysics Data System (ADS)

As the number and type of communications systems in use around the world multiplies so the need for gateways to allow these systems to interoperate increases. This is particularly true for global satellite systems that potentially need to interoperate with systems complying to widely different standards around the world. The ETSI proposed S-UMTS system and (significant) bandwidth allocation is intended to provide an important overlay to future terrestrial 3rd Generation networks. S-UMTS is specifically targeted at providing services in remote regions, or potentially just as important, when out of coverage of the subscriber's home network or a network with a suitable roaming agreement. Thus, satellite/terrestrial interoperability is a key issue to enable subscribers the standard and diversity of service offered by terrestrial systems plus the broad coverage offered by satellite systems. There are considerable technical challenges involved in achieving true interoperability between networks in the 2.5 and 3G world, and therefore in achieving the true vision of S-UMTS. One of the key technical issues is inter-working between different standards, which will continue into the 3G period due to the large number of different types of network (GSM, IS-41, PDC, CDMA, satellite, etc) employed throughout the world. Packet data roaming onto satellite networks is set to become a new important capability for business users in support of the global mobile office as GPRS and 3G services become more widespread. When out of terrestrial network coverage or when the availability of standard call or data transfer charges globally is needed, roaming onto satellite networks provides a very attractive solution. Using the Inmarsat system as an example this paper addresses how interoperability between satellite and terrestrial networks can be assured through the use of standard computer equipment running software-based gateways.

Davies, Phil; Hartwell, Gareth; Shave, Nick

2002-07-01

339

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 ...

Mrs. Nunes-Bufford

2010-10-27

340

Animal Communication  

NSDL National Science Digital Library

The focus of this Science NetLinks lesson is threefold. First, to expose students to the fact that all species have a capacity for communication. Second, to enlighten students to the fact that communication abilities range from very simple to extremely complex, depending upon the species. Third, to realize that communication is influenced by a species' genetic makeup, its environment, and the numerous ways by which animals and humans respond to and adapt to their surroundings.

Science Netlinks

2003-09-09

341

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

342

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

343

Terrestrial Planet Formation in the ? Centauri System  

NASA Astrophysics Data System (ADS)

We examine the late stages of terrestrial planet formation around each star in the ? Centauri 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 a single star with giant planets, they lead to systems most closely resembling our solar system. However, it is far from certain that such a planetesimal distribution actually occurs either in single or binary star systems. We follow the evolution of the accreting bodies at various values of the inclination of the midplane of the disk relative to the binary orbit for 200 Myr to 1 Gyr. In simulations in which the midplane of the disk was inclined <=30° relative to the binary orbital plane, three to five terrestrial planets were formed around ? Cen A. When the embryos in the disk were moving retrograde relative to the binary plane, four or five terrestrial planets formed. From two to five planets formed in a disk centered around ? Cen B, with ? Cen A perturbing the system in the same plane. The aforementioned resulting terrestrial planetary systems are quite similar to those produced by calculations of terrestrial planet growth in the Sun-Jupiter or Sun-Jupiter-Saturn systems. In contrast, terrestrial planet growth around a star lacking both stellar and giant planet companions is slower and extends to larger semimajor axis for the same initial disk of planetary embryos. In systems with the accreting disk initially inclined at 45° relative to the binary star orbit, two to five planets formed despite the fact that more than half of the disk mass was perturbed into the central star. When the disk was inclined at 60° to the binary plane, the stability of the planetary embryos decreased dramatically because of larger variations in eccentricity caused by the Kozai resonance, and almost all of the planetary embryos and planetesimals were lost from these systems.

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

2002-09-01

344

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

345

Space and Terrestrial Photovoltaics: Synergy and Diversity  

NASA Technical Reports Server (NTRS)

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

Bailey, Sheila; Raffaelle, Ryne; Emery, Keith

2002-01-01

346

Space and Terrestrial Photovoltaics: Synergy and Diversity  

NASA Astrophysics Data System (ADS)

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

Bailey, Sheila; Raffaelle, Ryne; Emery, Keith

2002-10-01

347

Climate science communication from researchers to diverse audiences  

NASA Astrophysics Data System (ADS)

Climate science is a topic that engenders a public response that is very different than the response to many other scientific fields. Communicating climate research results, therefore, presents a unique challenge to the researcher who wishes to put their results on a broader stage. Techniques of communicating climate science in a meaningful manner include understanding the audience in question, and presenting the scientific results in a way that engages the target audience in a manner that precludes cultural and political bias, both on the part of the presenter and in the elicited response from the audience. We hope to present experiences and lessons learned from presenting satellite-based climate research on behalf of NASA and NOAA projects, with respect to target audiences including K-12, higher education, citizen scientists, and the general public.

Rogers, M. A.

2011-12-01

348

Entanglement-based quantum communication over 144km  

NASA Astrophysics Data System (ADS)

Quantum entanglement is the main resource to endow the field of quantum information processing with powers that exceed those of classical communication and computation. In view of applications such as quantum cryptography or quantum teleportation, extension of quantum-entanglement-based protocols to global distances is of considerable practical interest. Here we experimentally demonstrate entanglement-based quantum key distribution over 144km. One photon is measured locally at the Canary Island of La Palma, whereas the other is sent over an optical free-space link to Tenerife, where the Optical Ground Station of the European Space Agency acts as the receiver. This exceeds previous free-space experiments by more than an order of magnitude in distance, and is an essential step towards future satellite-based quantum communication and experimental tests on quantum physics in space.

Ursin, R.; Tiefenbacher, F.; Schmitt-Manderbach, T.; Weier, H.; Scheidl, T.; Lindenthal, M.; Blauensteiner, B.; Jennewein, T.; Perdigues, J.; Trojek, P.; Ömer, B.; Fürst, M.; Meyenburg, M.; Rarity, J.; Sodnik, Z.; Barbieri, C.; Weinfurter, H.; Zeilinger, A.

2007-07-01

349

Communications diversity advantages for the Mobile User Objective System  

Microsoft Academic Search

The UHF radio frequency (RF) band available for the our future military Mobile User Objective System (MUOS) satellite communications system has to contend with the signal scintillation effects encountered from propagation through the ionosphere as well as multipath signals from terrestrial signal reflections that will be prominent with new handheld terminals. These effects cause signal fading which can severely degrade

Per A. Kullstam

2000-01-01

350

Long-Distance Quantum Communication with Entangled Photons using Satellites  

E-print Network

The use of satellites to distribute entangled photon pairs (and single photons) provides a unique solution for long-distance quantum communication networks. This overcomes the principle limitations of Earth-bound technology, i.e. the narrow range of some 100 km provided by optical fiber and terrestrial free-space links.

Markus Aspelmeyer; Thomas Jennewein; Martin Pfennigbauer; Walter Leeb; Anton Zeilinger

2003-05-19

351

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

352

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

353

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

354

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

355

Terrestrial Laser Scanner for Scour Visualizaton  

NASA Astrophysics Data System (ADS)

Examination of spatio-temporal variations of a terrestrial surface requires high-resolution measurements. Surface Examining Imager (SExI) developed by the University of Iowa Lidar Group is a terrestrial laser measurement system capable of spatially profiling a relatively small area (<20m^2) with mm-scale resolution. It was designed to be simple, affordable, and robust. Because the system employs line of sight principles, two SExIs can be deployed to scan the same area from different positions to see behind surface features and increase spatial resolution. Snell's law of refraction has been applied to underwater datasets to obtain a bathymetric survey for use in sediment scour visualization. This technique has been paired with Particle Image Velocimetry (PIV) to overlay surface velocity profiles on a raster image of the bathymetry.

Plenner, S.; Eichinger, W. E.

2011-12-01

356

The terrestrial bioluminescent animals of Japan.  

PubMed

Light production by organisms, or bioluminescence, has fascinated not only scientists but also ordinary people all over the world, and it has been especially so in Japan. Here we review the biological information available to date for all luminous terrestrial animals known from Japan, particularly focusing on their diversity and systematics, their biology and ecology in Japan, and putative function and biochemistry of their luminescence. In total 58 luminous terrestrial animals have been described from Japan, which consist of 50 fireflies (Coleoptera: Lampyridae), one glowworm beetle (Coleoptera: Phengodidae), two fungus gnats (Diptera: Keroplatidae), one springtail (Collembola), one millipede (Diplopoda), one centipede (Chilopoda) and two earthworms (Oligochaeta). For all except some firefly species, the DNA "barcode" sequences of a cytochrome oxidase subunit I region are provided. We also introduce how intricately the seasonal appearance and glimmering of luminous insects, in particular those of fireflies, have been interwoven into the culture, art, literature and mentality of Japanese people. PMID:22035300

Oba, Yuichi; Branham, Marc A; Fukatsu, Takema

2011-11-01

357

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.

358

Communication tools.  

PubMed

In this bimonthly series, the author examines how nurse educators can use Internet and Web-based computer technologies such as search, communication, and collaborative writing tools; social networking and social bookmarking sites; virtual worlds; and Web-based teaching and learning programs. This article describes Web-based communication tools and techniques to increase their effectiveness. PMID:19726955

Wink, Diane

2009-01-01

359

Speech Communication.  

ERIC Educational Resources Information Center

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

Anderson, Betty

360

Communicating up  

ERIC Educational Resources Information Center

Chief communicators at many U.S. institutions are interested in forging closer ties with governing boards. Proponents say such relationships can increase board trust and confidence in communicators before a crisis occurs, making it easier to manage the institution's reputation and limit negative publicity when one does. At some institutions, such…

Lum, Lydia

2013-01-01

361

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

362

Global change and terrestrial hydrology - A review  

NASA Technical Reports Server (NTRS)

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

Dickinson, Robert E.

1991-01-01

363

A toy terrestrial carbon flow model  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

364

Interferometer Designs for the Terrestrial Planet Finder  

NASA Technical Reports Server (NTRS)

The Terrestrial Planet Finder (TPF) is a space-based infrared interferometer that will combine high sensitivity and spatial resolution to detect and characterize planetary systems within 15 pc of our sun. TPF is a key element in NASA's Origins Program and is currently under study in its Pre-Project Phase. We review some of the interferometer designs that have been considered for starlight nulling, with particular attention to the architecture and subsystems of the central beam-combiner.

Lawson, P. R.; Dumont, P. J.; Colavita, M. M.

1999-01-01

365

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

366

Cosmogenic helium in a terrestrial igneous rock  

NASA Technical Reports Server (NTRS)

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

Kurz, M. D.

1986-01-01

367

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.

368

Long-period solar-terrestrial variability  

SciTech Connect

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

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

1991-01-01

369

Hydrolytic microbial communities in terrestrial ecosystems  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

370

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

371

Remote and terrestrial ground monitoring techniques integration for hazard assessment in mountain areas  

NASA Astrophysics Data System (ADS)

In high mountain regions the choice of appropriate sites for infrastructure such as roads, railways, cable cars or hydropower dams is often very limited. In parallel, the increasing demand for supply infrastructure in the Alps induces a continuous transformation of the territory. The new role played by the precautionary monitoring in the risk governance becomes fundamental and may overcome the modeling of future events, which represented so far the predominant approach to these sort of issues. Furthermore the consequence of considering methodologies alternative to those more exclusive allow to reduce costs and increasing the frequency of measurements, updating continuously the cognitive framework of existing hazard condition in most susceptible territories. The scale factor of the observed area and the multiple purpose of such regional ordinary surveys make it convenient to adopt Radar Satellite-based systems, but they need to be integrated with terrestrial systems for validation and eventual early warning purposes. Significant progress over the past decade in Remote Sensing (RS), Proximal Sensing and integration-based sensor networks systems now provide technologies, that allow to implement monitoring systems for ordinary surveys of extensive areas or regions, which are affected by active natural processes and slope instability. The Interreg project SloMove aims to provide solutions for such challenges and focuses on using remote sensing monitoring techniques for the monitoring of mass movements in two test sites, in South Tyrol (Italy) and in Grisons Canton (Switzerland). The topics faced in this project concern mass movements and slope deformation monitoring techniques, focusing mainly on the integration of multi-temporal interferometry, new generation of terrestrial technologies for differential digital terrain model elaboration provided by laser scanner (TLS), and GNSS-based topographic surveys, which are used not only for validation purpose, but also for adding value and information to the whole monitoring survey. The test sites are currently observed by an original integrated methodology specifically developed within the aim of the project. The integrated monitoring design includes reference targets for the different monitoring systems placed together on the same point or rigid foundation, to facilitate the comparison of the data and, in the operational use, to be able to switch consistently from one to the other system. The principal goal of the project is to define a shared procedure to select scalable technologies, best practices and institutional action plans more adequate to deal with different sort of hazard related to ground displacement, in densely populated mountain areas containing recreational and critical infrastructures. Keywords: integrated monitoring, multi-temporal interferometry, artificial reflectors; mass movement, SloMove.eu

Chinellato, Giulia; Kenner, Robert; Iasio, Christian; Mair, Volkmar; Mosna, David; Mulas, Marco; Phillips, Marcia; Strada, Claudia; Zischg, Andreas

2014-05-01

372

Assessing the Response of Terrestrial Ecosystems to Potential Changes in Precipitation  

NSDL National Science Digital Library

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

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

2003-09-01

373

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

374

Volcanic Signatures in Estimates of Stratospheric Aerosol Size, Distribution Width, Surface Area, and Volume Deduced from Global Satellite-Based Observations  

NASA Technical Reports Server (NTRS)

Volcanic signatures in the stratospheric aerosol layer are revealed by two independent techniques which retrieve aerosol information from global satellite-based observations of particulate extinction. Both techniques combine the 4-wavelength Stratospheric Aerosol and Gas Experiment (SAGE) II extinction measurements (0.385 <= lambda <= 1.02 microns) with the 7.96 micron and 12.82 micron extinction measurements from the Cryogenic Limb Array Etalon Spectrometer (CLAES) instrument. The algorithms use the SAGE II/CLAES composite extinction spectra in month-latitude-altitude bins to retrieve values and uncertainties of particle effective radius R(sub eff), surface area S, volume V and size distribution width sigma(sub R). The first technique is a multi-wavelength Look-Up-Table (LUT) algorithm which retrieves values and uncertainties of R(sub eff) by comparing ratios of extinctions from SAGE II and CLAES (e.g., E(sub lambda)/E(sub 1.02) to pre-computed extinction ratios which are based on a range of unimodal lognormal size distributions. The pre-computed ratios are presented as a function of R(sub eff) for a given sigma(sub g); thus the comparisons establish the range of R(sub eff) consistent with the measured spectra for that sigma(sub g). The fact that no solutions are found for certain sigma(sub g) values provides information on the acceptable range of sigma(sub g), which is found to evolve in response to volcanic injections and removal periods. Analogous comparisons using absolute extinction spectra and error bars establish the range of S and V. The second technique is a Parameter Search Technique (PST) which estimates R(sub eff) and sigma(sub g) within a month-latitude-altitude bin by minimizing the chi-squared values obtained by comparing the SAGE II/CLAES extinction spectra and error bars with spectra calculated by varying the lognormal fitting parameters: R(sub eff), sigma(sub g), and the total number of particles N(sub 0). For both techniques, possible biases in retrieved-parameters caused by assuming a unimodal functional form are removed using correction factors computed from representative in situ measurements of bimodal size distributions. Some interesting features revealed by the LUT and PST retrievals include: (1) Increases in S and V (but not R(sub eff)) after the Ruiz and Kelut injections, (2) Increases in S, V, R(sub eff) after Pinatubo, (3) Post-Pinatubo increases in S, V, and R(sub eff) that are more rapid in the tropics than elsewhere, (4) Mid-latitude post-Pinatubo increases in R(sub eff) that lag increases in S and V, (5) S and V returning to pre-Pinatubo values sooner than R(sub eff) does, (6) Sharp increases in sigma(sub g), after Pinatubo and slight increases in sigma(sub g) after Ruiz, Etna, Kelut, Spurr and Rabaul, and (7) Gradual declines in the heights at which R(sub eff), S and V peak after Pinatubo.

Bauman, J. J.; Russell, P. B.

2000-01-01

375

Trends in Oceanic Evaporation retrieved from the Goddard Satellite-based Surface Turbulent Fluxes based on SSM/I v6 (GSSTF2b) Dataset  

NASA Astrophysics Data System (ADS)

Trends and variability in global oceanic evaporation data sets have been examined for the period 1988-2000 by Chiu et al. (Acta Oceanologica Sinica, 2008). These data sets are satellite estimates based on bulk aerodynamic formulations and include the NASA/Goddard Space Flight Center Satellite-based Surface Turbulent Flux version 2 (GSSTF2), the Japanese-Ocean Flux Using Remote Sensing Observations (J-OFURO), the Hamburg Ocean-Atmosphere Parameters and Fluxes from Satellite version 2 (HOAPS2). The National Center for Environmental Prediction (NCEP) reanalysis has also been included for comparison. An increase in global average surface latent heat flux (SLHF) can be observed in all the data sets. Empirical Mode Decomposition (EMD) shows long-term increases that started around 1990 for all remote sensing datasets. The effect of Mt. Pinatubo eruption in 1991 is clearly evident in HOAPS2 but is independent of the long-term increase. Linear regression analyses show increases of 9.4%, 13.0%, 7.3%, and 3.9% for GSSTF2, J-OFURO, HOAPS2 and NCEP, for the periods of the datasets. Empirical Orthogonal Function (EOF) analyses show that the pattern of the first EOF of all datasets is consistent with a decadal variation associated with the enhancement of the tropical Hadley circulation, which is supported by other satellite observations. The second EOF of all four data sets is an ENSO mode, and the correlations between their time series and an SOI are 0.74, 0.71, 0.59, and 0.61 for GSSTF2, J-OFURO, HOAPS2, and NCEP in that order. When the Hadley modes are removed from the remote sensing data, the residue global increases are reduced to 2.2%, 7.3%, and <1% for GSSTF2, J-OFURO and HOAPS, respectively. If the ENSO mode is used as a calibration standard for the datasets, the Hadley mode is at least comparable to, if not larger than, the ENSO mode during our study period. Most of these products have relied on Special Sensor Microwave Imager (SSM/I) data taken on board the Defense Meteorological Satellite Program (DMSP). The GSSTF2 product was based on the V4 of SSM/I data that have been preprocessed by Remote Sensing System. In 2007, RSS provides an improved version (version 6) of the SSM/I and recommends its use for climate studies. Shie et al. (Adv. Atmo. Sci., 2009) extend the GSSTF product to date and incorporate the SSM/I version 6 data to produce a GSSTF2b product. GSSTF2b will be analyzed to quantify the persistence of the long term trends and variability. Our preliminary results show that GSSTF2 generally has larger positive trend (could be less negative trend somewhere, though) in SLHF than GSSTF2b for regions between 40S-40N, while GSSTF2 has larger negative trend in SLHF (or could be less positive trend) than GSSTF2b for regions beyond.

Gao, S.; Chokngamwong, R.; Chiu, L.; Shie, C.; Xie, P. P.; Adler, R. F.; Nelkin, E. J.

2009-12-01

376

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.

0000-00-00

377

Proximity communication  

Microsoft Academic Search

This paper reports results from wireless chip to chip communication experiments. Sixteen bit words pass from one chip to another in parallel without detectable error at 1.35 billion data items per second for a total data rate of 21.6 Gigabits per second. The experiment transmits pseudo random patterns between chips built in 350nm CMOS technology. Chips touch face-to-face to communicate.

Robert J. Drost; Robert David Hopkins; Ivan E. Sutherland

2004-01-01

378

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 Jozef

379

Teppeki, selective insecticide about Bombus terrestris.  

PubMed

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

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

2009-01-01

380

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

381

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

382

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

383

Terrestrial Effects of High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

On geological timescales, the Earth is likely to be exposed to an increased flux of high energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma ray bursts or by galactic shocks. These high-energy particles strike the Earth's atmosphere initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing charged secondary particles. Increased ionization could lead to changes in atmospheric chemistry, resulting in ozone depletion. This could increase the flux of solar UVB radiation at the surface, which is potentially harmful to living organisms. Increased ionization affects the global electrical circuit can could possibly enhance the low-altitude cloud formation rate. Secondary particles such as muons and thermal neutrons produced as a result of nuclear interactions are able to reach the ground, enhancing the biological radiation dose. The muon flux dominates radiation dose from cosmic rays causing DNA damage and increase in the mutation rates, which can have serious biological implications for terrestrial and sub-terrestrial life. This radiation dose is an important constraint on the habitability of a planet. Using CORSIKA, we perform massive computer simulations and construct lookup tables from 10 GeV - 1 PeV primaries (1 PeV - 0.1 ZeV in progress), which can be used to quantify these effects. These tables are freely available to the community and can be used for other studies, not necessarily relevant to Astrobiology. We use these tables to study the terrestrial implications of galactic shock generated by the infall of our galaxy toward the Virgo cluster. This could be a possible mechanism explaining the observed periodicity in biodiversity in paleobiology databases.

Atri, Dimitra

2011-01-01

384

Aquatic predation alters a terrestrial prey subsidy.  

PubMed

Organisms with complex life histories (CLH) often cross habitat or ecosystem boundaries as they develop from larvae to adults, coupling energy flow between ecosystems as both prey (bottom-up) and consumers (top-down). Predation effects on one stage of this life cycle can therefore cascade across ecosystems, magnifying the impact of local predation. The majority of predation studies have assessed effects only on a local level, within the habitat of the predator. I used large outdoor stream mesocosms to test the hypothesis that predation in an aquatic habitat alters the magnitude and trophic structure of a prey assemblage in a terrestrial habitat. I also tested how a consumer in the terrestrial habitat (web-weaving spiders) responded to these changes in prey export. Two fish species were the predators (red shiner, Cyprinella lutrensis and orangethroat darter, Etheostoma spectabile) in an experiment with three treatments: both fish species monocultures plus a fishless control. Fish predation reduced aquatic insect emergence biomass by 50% compared to the fishless control and altered the trophic structure of the emergent community, reducing emerging insect predator biomass by 50%, but had no effect on other insect trophic groups. Spiders captured only insects that were unaffected by fish predation (mostly chironomids) and therefore did not respond numerically to overall changes in insect abundance or biomass. Patterns of insect emergence were largely driven by a strong negative relationship between fish and a predatory dragonfly (Pantala flavescens). The results of this experiment show that predation in one habitat can have strong effects on the biomass and trophic structure of subsidies entering adjacent habitats, resulting in contrasting predictions for the role of these subsidies in recipient food webs. In the absence of fish, aquatic habitats produced terrestrial insect communities with higher biomass (bottom-up potential) and a higher proportion of predators (top-down potential) than when fish were present. PMID:20503875

Wesner, Jeff Scott

2010-05-01

385

Terrestrial Planet Growth in Circumbinary Disks  

NASA Technical Reports Server (NTRS)

We examine the accuulation of terrestrial from circumbinary disks surrounding pairs of stars with masses of either 0.5 solar masses each or 0.8 and 0.2 solar masses and orbital separations of 0.05 AU to 0.4 AU by performing numerical simulations of the late stages of planetary growth. Initial disks contain about 2.6 Earth masses of lunar to Mars-sized bodies orbiting within 2 AU of the center of mass of the system, plus giant planets with masses and orbits analogous to those of Jupiter and Saturn. We also performed simulations using analogous disks orbiting single 1 solar mass stars. The dynamics of planetary growth is quite chaotic because the gravitational perturbations resulting from close approaches greatly amplify differences in orbits. Thus, several simulations of each configuration were run with very slightly different initial conditions to enable us to distinguish systematic effects resulting from differences in the binary orbit (or differences of the initial orbits of the bodies within the disk) from pseudo-random variability in outcomes resulting from chaos. Most runs simulated 200 million years of evolution. At least one terrestrial planet remained at the end of each run; one simulation produced 6 terrestrial planets in a configuration that appears to be quite stable. The systems that formed around stars with binary apastron separations of less than 0.2 AU contained on average slightly more planets than those that formed around single stars, with the outermost planet typically orbiting at a greater distance from the system barycenter. Greater stellar separations tended to result in fewer planets, with the inner planet orbiting farther from the stars. More eccentric binaries have a more pronounced effect for the same apastron distance. The statistical distribution of final systems is not sensitive to moderate differences in the initial eccentricities of the bodies in the disk.

Lissauer, J. J.; Quintana, E. V.

2006-01-01

386

Terrestrial and freshwater Tardigrada of the Americas.  

PubMed

This paper provides a comprehensive list of the freshwater and terrestrial tardigrade fauna reported from the Americas (North America, South America, Central America and the West Indies), their distribution in the Americas, and the substrates from which they have been reported. Data were obtained from 316 published references. Authors' identifications were accepted at face value unless subsequently amended. Taxa were assigned to sub-national units (states, provinces, etc.). Many areas, in particular large portions of Central America and the West Indies, have no reported tardigrade fauna.        The presence of 54 genera and 380 species has been reported for the Americas; 245 species have been collected in the Nearctic ecozone and 251 in the Neotropical ecozone. Among the tardigrade species found in the Americas, 52 are currently considered cosmopolitan, while 153 species have known distributions restricted to the Americas. Based on recent taxonomic revision of the genus Milnesium, the vast majority of records of M. tardigradum in the Americas should now be reassigned to Milnesium tardigradum sensu lato, either because the provided description differs from M. tardigradum sensu stricto or because insufficient description is provided to make a determination; the remainder should be considered Milnesium cf. tardigradum.        Most terrestrial tardigrade sampling in the Americas has focused on cryptogams (mosses, lichens and liverworts); 90% of the species have been collected in such substrates. The proportion of species collected in other habitats is lower: 14% in leaf litter, 20% in soil, and 24% in aquatic samples (in other terrestrial substrates the proportion never exceeds 5%). Most freshwater tardigrades have been collected from aquatic vegetation and sediment. For nine species in the Americas no substrates have been reported.  PMID:25113595

Meyer, Harry A

2013-01-01

387

Design for minimum energy in interstellar communication  

NASA Astrophysics Data System (ADS)

Microwave digital communication at interstellar distances is the foundation of extraterrestrial civilization (SETI and METI) communication of information-bearing signals. Large distances demand large transmitted power and/or large antennas, while the propagation is transparent over a wide bandwidth. Recognizing a fundamental tradeoff, reduced energy delivered to the receiver at the expense of wide bandwidth (the opposite of terrestrial objectives) is advantageous. Wide bandwidth also results in simpler design and implementation, allowing circumvention of dispersion and scattering arising in the interstellar medium and motion effects and obviating any related processing. The minimum energy delivered to the receiver per bit of information is determined by cosmic microwave background alone. By mapping a single bit onto a carrier burst, the Morse code invented for the telegraph in 1836 comes closer to this minimum energy than approaches used in modern terrestrial radio. Rather than the terrestrial approach of adding phases and amplitudes increases information capacity while minimizing bandwidth, adding multiple time-frequency locations for carrier bursts increases capacity while minimizing energy per information bit. The resulting location code is simple and yet can approach the minimum energy as bandwidth is expanded. It is consistent with easy discovery, since carrier bursts are energetic and straightforward modifications to post-detection pattern recognition can identify burst patterns. Time and frequency coherence constraints leading to simple signal discovery are addressed, and observations of the interstellar medium by transmitter and receiver constrain the burst parameters and limit the search scope.

Messerschmitt, David G.

2015-02-01

388

Ammonia transport by terrestrial and aquatic insects.  

PubMed

Ammonia, an end product from amino acid and nucleic acid metabolism, is highly toxic for most animals. This review will provide an update on nitrogen metabolism in terrestrial and aquatic insects with emphasis on ammonia generation and transport. Aspects that will be discussed include metabolic pathways of nitrogenous compounds, the origin of ammonia and other nitrogenous waste products, ammonia toxicity, putative ammonia transporters as well as ammonia transport processes known in insects. Ammonia transport mechanisms in the mosquito Aedes aegypti, the tobacco hornworm Manduca sexta and the locust Schistocerca gregaria will be discussed in detail while providing additional, novel data. PMID:22100291

Weihrauch, Dirk; Donini, Andrew; O'Donnell, Michael J

2012-04-01

389

International Solar Terrestrial Physics (ISTP) program  

NASA Technical Reports Server (NTRS)

The International Solar Terrestrial Physics (ISTP) Program is a large, multi-national program involving three space agencies and up to eight spacecraft. NASA, together with the Institute of Space and Astronomical Science (ISAS) and the European Space Agency (ESA), has agreed in principle to coordinate their efforts in investigating the Sun and the Earth. Each agency is planning to construct and operate different spacecraft as part of this cooperative venture: Geotail provided by ISAS, the Solar Heliospheric Observatory (SOHO) and Cluster (four spacecraft) contributed by ESA, and Wind and Polar by NASA. A general description of the program is presented.

Sanford, R.; Muhonen, D.; Sizemore, K. O.

1991-01-01

390

Terrestrial planet composition: simulation and observation  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

391

Fermi GBM Observations of Terrestrial Gamma Flashes  

NASA Technical Reports Server (NTRS)

In its first two years of operation, the Fermi Gamma Ray Burst Monitor (GBM) has observed 79 Terrestrial Gamma Flashes (TGFs). The thick Bismuth Germanate (BGO) detectors are excellent for TGF spectroscopy, having a high probability of recording the full energy of an incident photon, spanning a broad energy range from 150 keV to 40 MeV, and recording a large number of photons per TGF. Correlations between GBM TGF triggers and lightning sferics detected with the World-Wide Lightning Location Network indicate that TGFs and lightning are simultaneous to within tens of microseconds.

Wilson-Hodge, Colleen A.; Briggs, M. S.; Connaughton, V.; Fishman, G. J.; Bhat, P. N.; Paciesas, W. S.; Preece, R. D.; Kippen, R. M.; vonKienlin, A.; Dwyer, J. R.; Smith, D. M.; Holzworth, R.

2010-01-01

392

Identification of Terrestrial Reflectance From Remote Sensing  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

393

Terrestrial Gamma-Ray Flashes (TGFs)  

NASA Technical Reports Server (NTRS)

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

Fishman, Gerald J.

2010-01-01

394

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

Microsoft Academic Search

We report the first systematic study 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 well with cosmic-ray-produced helium-3 and neon-21 concentrations in the same samples, implying that the manganese-53 is produced continuously in situ and retained quantitatively over millions of years. The terrestrial

Joerg M. Schaefer; Thomas Faestermann; Gregory F. Herzog; Klaus Knie; Gunther Korschinek; Jozef Masarik; Astrid Meier; Michail Poutivtsev; Georg Rugel; Christian Schlüchter; Feride Serifiddin; Gisela Winckler

2006-01-01

395

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

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

396

Bryophyte Influence on terrestrial and Epiphytic Fern Gametophytes.  

E-print Network

??The climate and structural complexity of tropical forests enable vertical habitat differentiation between epiphytic and terrestrial communities. Because fern spores are copiously released one might… (more)

McCarthy, Mirabai Rachel

2007-01-01

397

15. PALEOLIMNOLOGY OF EXTREME COLD TERRESTRIAL AND EXTRATERRESTRIAL ENVIRONMENTS  

E-print Network

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

Priscu, John C.

398

Constraining uncertainties in terrestrial carbon cycle modeling  

NASA Astrophysics Data System (ADS)

Global climate models differ in their representation of uptake of CO2 in the biosphere. Our study focuses on constraining the uncertainty in terrestrial carbon cycle modeling by comparing climate model results to observed atmospheric CO2 concentrations. The goal is to improve the representations of the seasonal cycle of terrestrial carbon uptake in the land model. We use the NCAR Community Earth System Model (CESM) climate components CLM4CN and CAM4 to run a prognostic version of the coupled land-atmosphere model where the atmospheric CO2 concentration in CAM4 is interactively calculated. Atmospheric CO2 concentrations from the model are compared to observations provided by flux towers in the AMERIFLUX network through the FLUXNET database and from the WDCGG for year 2000. We compare model results from sensitivity studies using different Q10 and Vcmax parameterizations, which are important functions in calculating plant growth. The carbon uptake in the biosphere is also under anthropogenic influence through emission of nitrogen and ozone from air pollution. Whereas nitrogen limitations in the soil reduce land ecosystem response to increasing CO2 concentrations, nitrogen from anthropogenic emissions increases the nitrogen availability and hence stimulates plant growth. These two nitrogen effects as well as the damaging impact on plants due to tropospheric ozone fertilization have been included in this study.

Kvalevåg, M.; Myhre, G.

2011-12-01

399

An Imaging Interferometer for Terrestrial Remote Sensing  

NASA Technical Reports Server (NTRS)

A prototype imaging interferometer called DASI (digital array scanned interferometer) is under development at our laboratories. Our objective is to design an instrument for remote sensing of Earth's atmosphere and surface. This paper describes the unusual characteristics of DASIs which make them promising candidates for ground and aircraft-based terrestrial measurements. These characteristics include superior signal-to-noise, design simplicity and compactness, relative to dispersion based imaging spectrometers. Perhaps one of the most notable features of DASIs is their ability to acquire an entire interferogram simultaneously without any moving optical elements. We also describe selected laboratory and ground based field measurements using the prototype DASI. A CCD detector array was placed at the DASI detector plane for wavelength coverage from 0.4 to 1.0 micron. A NICMOS MCT detector was used for coverage from 1.1 to 2.2 micron. The DASI was configured to have a spectral resolution of about 300 1/cm, a spatial field of view of 5 degrees, and a constant number of transverse spatial elements (detector dependent) for each exposure frame. Frame exposure rates were up to 0.6 Hz with the potential to achieve 5 Hz. Image cube measurements of laboratory targets and terrestrial scenes were obtained by multiple frame scanning over the field of view. These data sets reveal the potential science yields from obtaining simultaneous high resolution spatial and spectral information.

Hammer, Philip D.; Valero, Francisco P. J.; Peterson, David L.; Smith, William Hayden

1993-01-01

400

Lunar apatite with terrestrial volatile abundances.  

PubMed

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

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

2010-07-22

401

Terrestrial applications of the heatpipe power system  

SciTech Connect

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

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

1997-02-01

402

Classification and generation of terrestrial rare gases  

NASA Technical Reports Server (NTRS)

A Kr-84/Xe-130 versus Ne-20/Ar-36 diagram is a very useful format with which to study the elemental ratios of rare gases from terrestrial materials. It can separate not only the three types of rare gases which Ozima and Alexander (1976) classified but also the 'planetary' type rare gases from the other three types of rare gases. When all the available terrestrial rare gas data are plotted in a Kr-84/Xe-130 versus Ne-20/Ar-36 diagram, several observations can be made. First, most of the analyses of rare gases from shales yield Kr-84/Xe-130 ratios between the 'planetary' and atmospheric values. If, however, the atmosphere's high Kr-84/Xe-130 ratio was produced by the selective adsorption of xenon onto shales from an initially 'planetary' atmosphere, as is widely accepted, then the Kr-84/Xe-130 ratio in shales should be even lower than the 'planetary' value. Second, the rare gas pattern in the quenched rims of submarine basalts may be explained as fractionated samples of the rare gases in sea water.

Saito, K.

1978-01-01

403

Solar-terrestrial coupling through atmospheric electricity  

NASA Technical Reports Server (NTRS)

There are a number of measurements of electrical variations that suggest a solar-terrestrial influence on the global atmospheric electrical circuit. The measurements show variations associated with solar flares, solar magnetic sector boundary crossings, geomagnetic activity, aurorae, differences between ground current and potential gradients at high and low latitudes, and solar cycle variations. The evidence for each variation is examined. Both the experimental evidence and the calculations made with a global model of atmospheric electricity indicate that there is solar-terrestrial coupling through atmospheric electricity which operates by altering the global electric current and field distribution. A global redistribution of currents and fields can be caused by large-scale changes in electrical conductivity, by alteration of the columnar resistance between thunderstorm cloud tops and the ionosphere, or by both. If the columnar resistance is altered above thunderstorms, more current will flow in the global circuit, changing the ionospheric potential and basic circuit variables such as current density and electric fields. The observed variations of currents and fields during solar-induced disturbances are generally less than 50% of mean values near the earth's surface.

Roble, R. G.; Hays, P. B.

1979-01-01

404

Grazers: biocatalysts of terrestrial silica cycling  

PubMed Central

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

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

2013-01-01

405

Advanced Stirling conversion systems for terrestrial applications  

NASA Technical Reports Server (NTRS)

Under the Department of Energy's (DOE) Solar Thermal Technology Program, Sandia National Laboratories (SNLA) is developing heat engines for terrestrial Solar Distributed Heat Receivers. SNLA has identified the Stirling to be one of the most promising candidates for the terrestrial applications. The free-piston Stirling engine (FPSE) has the potential to meet the DOE goals for both performance and cost. The National Aeronautics and Space Administration (NASA) Lewis Research Center (LeRC) is conducting free-piston Stirling activities which are directed toward a dynamic power source for space applications. Space power system requirements include high efficiency, very long life, high reliability and low vibration. The FPSE has the potential for future high power space conversion systems, either solar or nuclear. Generic free-piston technology is currently being developed by LeRC for DOE/ORNL for use with a residential heat pump under an Interagency Agreement. Since 1983, the SP-100 Program (DOD/NASA/DOE) is developing dynamic power sources for space. Although both applications (heat pump and space power) appear to be quite different, their requirements complement each other. A cooperative Interagency Agreement (IAA) was signed in 1985 with NASA Lewis to provide technical management for an Advanced Stirling Conversion System (ASCS) for SNLA. Conceptual design(s) using a free-piston Stirling (FPSE), and a heat pipe will be discussed. The ASCS will be designed using technology which can reasonably be expected to be available in the 1980's.

Shaltens, R. K.

1987-01-01

406

Terrestrial Planet Formation in Binary Star Systems  

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 within binary star systems, using a new, ultrafast, symplectic integrator that we have developed for this purpose. We show that the late stages of terrestrial planet formation can indeed take place in a wide variety of binary systems and we have begun to delineate the range of parameter space for which this statement is true. Results of our initial simulations of planetary growth around each star in the alpha Centauri system and other 'wide' binary systems, as well as around both stars in very close binary systems, will be presented.

Lissauer, Jack J.; Quintana, Elisa V.; Chambers, John; Duncan, Martin J.; Adams, Fred

2003-01-01

407

Advanced Stirling conversion systems for terrestrial applications  

SciTech Connect

Sandia National Laboratories (SNLA) is developing heat engines for terrestrial Solar distributed Heat Receivers. SNLA has identified the Stirling to be one of the most promising candidates for the terrestrial applications. The free-piston Stirling engine (FPSE) has the potential to meet the DOE goals for both performance and cost. Free-piston Stirling activities which are directed toward a dynamic power source for the space application are being conducted. Space power system requirements include high efficiency, very long life, high reliability and low vibration. The FPSE has the potential for future high power space conversion systems, either solar or nuclear powered. Generic free-piston technology is currently being developed for use with a residential heat pump under an Interagency Agreement. Also, an overview is presented of proposed conceptual designs for the Advanced Stirling Conversion System (ASCS) using a free-piston Stirling engine and a liquid metal heat pipe receiver. Power extraction includes both a linear alternator and hydraulic output capable of delivering approximately 25 kW of electrical power to the electric utility grid. Target cost of the engine/alternator is 300 dollars per kilowatt at a manufacturing rate of 10,000 units per year. The design life of the ASCS is 60,000 h (30 y) with an engine overhaul at 40,000 h (20 y). Also discussed are the key features and characteristics of the ASCS conceptual designs.

Shaltens, R.K.

1987-01-01

408

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

409

Understanding of crop phenology using satellite-based retrievals and climate factors - a case study on spring maize in Northeast China plain  

NASA Astrophysics Data System (ADS)

Land surface phenology is an efficient bio-indicator for monitoring terrestrial ecosystem variation in response to climate change. Numerous studies point out climate change plays an important role in modulating vegetation phenological events, especially in agriculture. In turn, surface changes caused by geo-biological processes can affect climate transition regionally and perhaps globally, as concluded by Intergovernmental Panel on Climate Change (IPCC) in 2001. Large amounts of research concluded that crops, as one of the most sensitive bio-indicators for climate change, can be strongly influenced by local weather such as temperature, moisture and radiation. Thus, investigating the details of weather impact and the feedback from crops can help improve our understanding of the interaction between crops and climate change at satellite scale. Our efforts start from this point, via case studies over the famous agriculture region in the Northeast China's plain to examine the response of spring maize under temperature and moisture stress. MODIS-based daily green vegetation information together with frequent field specification of the surface phenology as well as continuous measurements of the routine climatic factors during seven years (2003-2009) is used in this paper. Despite the obvious difference in scale between satellite estimations and field observations, the inter- and intra-annual variation of maize in seven-years' growth was captured successfully over three typical spring maize regions (Fuyu, Changling, and Hailun) in Northeast China. The results demonstrate that weather conditions such as changes of temperature and moisture stress provide considerable contribution to the year-to-year variations in the timing of spring maize phenological events.

Shuai, Yanmin; Xie, Donghui; Wang, Peijuan; Wu, Menxin

2014-03-01

410

Communications Network  

NASA Technical Reports Server (NTRS)

The Multi-Compatible Network Interface Unit (MCNIU) is intended to connect the space station's communications and tracking, guidance and navigation, life support, electric power, payload data, hand controls, display consoles and other systems, and also communicate with diverse processors. Honeywell is now marketing MCNIU commercially. It has applicability in certain military operations or civil control centers. It has nongovernment utility among large companies, universities and research organizations that transfer large amounts of data among workstations and computers. *This product is no longer commercially available.

1990-01-01

411

COLD CLIMATE OIL SPILLS: A TERRESTRIAL AND FRESHWATER RESEARCH REVIEW  

EPA Science Inventory

The first part of this study reviews world-wide research on cold climate oil spills on land to identify some of the terrestrial environmental factors in cold regions affected by oil spills and some of the techniques for measuring impacts and terrestrial systems, primarily soils. ...

412

The effects of forest management on terrestrial salamanders  

Microsoft Academic Search

Maintaining a balance of timber production and conservation in forest management requires an understanding of how timber harvest techniques affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and their sensitivity to environmental change. The topic of timber harvests and their effect on terrestrial salamanders has received much attention

Jami E MacNeil

2011-01-01

413

Concordance of freshwater and terrestrial biodiversity Robin Abell1  

E-print Network

, & Jonathan Hoekstra2 1 World Wildlife Fund, 1250 24th St. NW, Washington, D.C., USA 2 The Nature Conservancy-setting; rarity-weighted richness; terrestrial. Correspondence Robin Abell, World Wildlife Fund, 1250 24th St. NW of equivalent terrestrial importance. A new global database of freshwater fish distributions enabled

Vermont, University of

414

Benchmark analysis of parameterization for terrestrial carbon cycle model (Invited)  

Microsoft Academic Search

Parameterization of terrestrial ecosystem models plays an important role in accurately predicting carbon-climate feedback. More and more studies have shown that a fixed set of parameters cannot adequately represent spatial and temporal variations of ecosystem functions over broad geographical locations and\\/or over long time. In this study, we conducted benchmark analysis of a terrestrial ecosystem (TECO) model against a highly

Y. Luo; X. Zhou; P. Verburg; J. Arnone

2010-01-01

415

DOES TERRESTRIAL CARBON SUBSIDIZE PRODUCTION OF ESTUARINE FISH LARVAE?  

EPA Science Inventory

The research presented demonstrates the important role that terrestrial ecosystems can play in coastal food webs. We show that terrestrial carbon subsidizes the tidal freshwater and oligohaline portions of an estuarine food web, but that this exogenous carbon source is not impor...

416

China-US Collaborative Research on Life in Terrestrial  

E-print Network

Symposium: China-US Collaborative Research on Life in Terrestrial Geothermal Springs Information, Agenda, and Abstracts June 26-28, 2013, Kunming, China #12;Symposium: China-US Collaborative Research on Life in Terrestrial Geothermal Springs Kunming, China June 26-28, 2013 Information, Agenda

Ahmad, Sajjad

417

Can Terrestrial Planets Form in Hot-Jupiter Systems?  

E-print Network

Models of terrestrial planet formation in the presence of a migrating giant planet have challenged the notion that hot-Jupiter systems lack terrestrial planets. We briefly review this issue and suggest that hot-Jupiter systems should be prime targets for future observational missions designed to detect Earth-sized and potentially habitable worlds.

Martyn J. Fogg; Richard P. Nelson

2007-10-19

418

Zoogeographic distribution of terrestrial\\/freshwater tardigrades from current literature  

Microsoft Academic Search

The literature on terrestrial and freshwater Tardigrada is relatively limited, being concerned with 617 species world wide. Many of the references are in obscure publications. This paper attempts to bring this information together, tabulating the numbers of tardigrade species recorded from terrestrial and freshwater habitats in various countries and the number of countries from which tardigrades have been recorded. Each

S. J. McInnes

1994-01-01

419

SYMPOSIUM-IN-PRINT: ULTRAVIOLET RADIATION AND TERRESTRIAL ECOSYSTEMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

This article provides an introduction to a Symposium-in-Print on “Ultraviolet Radiation and Terrestrial Ecosystems”and summarizes the findings of ten papers that were presented at an invited “Symposium on UV Effects on Terrestrial Ecosystems” held at the annual meeting of the American Society for Ph...

420

Exploring the Sensitivity of Terrestrial Ecosystems and Atmospheric Exchange  

E-print Network

Exploring the Sensitivity of Terrestrial Ecosystems and Atmospheric Exchange of CO2 to Global, USA December 5-9, 2011 #12;ISAM Estimated Net Ecosystem Exchange (NEE) Winter (DJF) Summer (JJA) 1996- 1997 1999- 2000 1990s negative is net C gain by the terrestrial ecosystems #12;Environmental Factors

Jain, Atul K.

421

The Geochronology of Terrestrial Meteorite and Cometary Impacts  

Microsoft Academic Search

Geochronology has become a crucial part of the debate over the influx of extraterrestrial material and its long term importance to terrestrial life. Many of the known terrestrial craters have ages attached to them, but all too often the ages are imprecise and unfortunately some are inaccurate. Despite these problems the database of measured ages has been used to support

S. P. Kelley

2003-01-01

422

Terrestrial Models and Global Change: Challenges for the Future  

NASA Technical Reports Server (NTRS)

A wide variety of models have illustrated the potential importance of terrestrial biological feedbacks on climate and climate change, yet our ability to make precise predictions is severely limited, due to a high degree of uncertainty. In this paper, after briefly reviewing current models, we present challenges for new terrestrial models and introduce a simple mechanistic approach that may complement existing approaches.

Hurtt, George C.; Moorcroft, Paul R.; Pacala, Stephen W.; Levin, Simon A.

1998-01-01

423

Management opportunities for enhancing terrestrial CO2 sinks  

Technology Transfer Automated Retrieval System (TEKTRAN)

To address climate change and the implications of a global mean temperature increase of more than two degrees Celsius over current levels will require terrestrial carbon (C) management along with reductions in fossil fuel emissions. To achieve all or part of the global terrestrial C sequestration p...

424

Satellite and terrestrial integrated services digital networks in Japan  

Microsoft Academic Search

Satellite and terrestrial Integrated Services Digital Networks (ISDN) to provide cost effective ISDN services and to enhance installation of ISDN services all over the nation are proposed. The proposed networks are based on the traffic sharing between satellite and terrestrial networks for traffic transmission among telephone offices and provide satellite subscriber lines for ISDN customers in rural areas. The former

Heiichi Yamamoto; Shuzo Kato

1991-01-01

425

Earth station site engineering in a terrestrial interference environment  

Microsoft Academic Search

Reception of C-band satellite television signals is now widespread throughout Canada. One problem that many satellite users still face is signal degradation due to terrestrial interference. The desired satellite signal is deteriorated due to the simultaneous reception of an unwanted microwave signal originating from land based (terrestrial) common carrier transmission networks. Careful antenna site engineering can reduce interfering carrier levels

Ralph Voneppinghoven

1989-01-01

426

Energetic Metastable Oxygen and Nitrogen Atoms in the Terrestrial Atmosphere  

NASA Technical Reports Server (NTRS)

We have investigated the energy distributions of the metastable oxygen atoms in the terrestrial thermosphere. Nascent O(lD) atoms play a fundamental role in the energy balance and chemistry of the terrestrial atmosphere, because they are produced by photo-chemical reactions in the excited electronic states and carry significant translational energies.

Kharchenko, Vasili

2003-01-01

427

Corporate strategies for satellite communications  

NASA Astrophysics Data System (ADS)

Terrestrial and satellite broadcast communications technologies, while clearly providing tremendous benefits in many market sectors, present something of a challenge to the strategic planning bodies in most organizations. This is because there is no existing analog for the services in the organizations' telecommunications networks. The marketplace is therefore a confusing place for such organizations swamped as it is with competing service providers, technologies, and services, and their telecommunications strategies cannot cope with the opportunities because they have been founded on the exploitation of point to point connections. A mechanism for creating and bounding strategies which combines the rigor of structured analysis with a comprehensive categorization of strategic directions which has been successfully used to generate new paneuropean telecommunications strategies is presented.

Birch, David G. W.; Buck, S. Peter

1991-10-01

428

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

429

Communicator, 1999.  

ERIC Educational Resources Information Center

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

Gosfield, Margaret, Ed.

1999-01-01

430

Communicative networks  

Microsoft Academic Search

This essay introduces the concept of communicative networks by analyzing Jacob A. Riis's journalistic attempts to solve social problems in New York's slums at the turn of last century. This renowned social reformer not only believed in the mobilizing potential of various networks for public transportation, but also established networks of his own through his books and newspaper articles, which

Peter Bro

2004-01-01

431

49. Communication  

NSDL National Science Digital Library

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

Cadwallader, Lynn

2013-01-01

432

Core Communications  

ERIC Educational Resources Information Center

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

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

2011-01-01

433

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

434

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

435

Similarity laws of lunar and terrestrial volcanic flows  

NASA Technical Reports Server (NTRS)

A mathematical model of a one dimensional, steady duct flow of a mixture of a gas and small solid particles (rock) was analyzed and applied to the lunar and the terrestrial volcanic flows under geometrically and dynamically similar conditions. Numerical results for the equilibrium two phase flows of lunar and terrestrial volcanoes under similar conditions are presented. The study indicates that: (1) the lunar crater is much larger than the corresponding terrestrial crater; (2) the exit velocity from the lunar volcanic flow may be higher than the lunar escape velocity but the exit velocity of terrestrial volcanic flow is much less than that of the lunar case; and (3) the thermal effects on the lunar volcanic flow are much larger than those of the terrestrial case.

Pai, S. I.; Hsu, Y.; Okeefe, J. A.

1977-01-01

436

Terrestrial short-term ecotoxicity of a green formicide.  

PubMed

When ants become annoying, large quantities of formicide are applied to terrestrial ecosystems in tropical regions, but awareness of the health and environmental impacts related to the use of synthetic pesticides has been increasing. The use of green pesticides to combat target organisms could reduce these impacts. In this regard, terrestrial ecotoxicity tests with higher plants (Brassica olaracea, Lactuca sativa and Mucuna aterrima), annelids (Eisenia foetida), Collembola (Folsomia candida) and soil enzyme activity analysis (diacetate fluorescein hydrolysis) were used to evaluate short-term terrestrial ecotoxicity of a green pesticide prepared from naturally-occurring organic compounds. At the highest formicide concentration tested in these experiments (i.e., 50 g kg(-1) soil) no toxicity toward terrestrial organisms was observed. The lack of short-term terrestrial ecotoxicity suggest that this green formicide can be classed as an environmentally friendly product as compared to the ecotoxicity of the most commonly used commercialized formicides. PMID:20117837

Tiepo, Erasmo N; Corrêa, Albertina X R; Resgalla, Charrid; Cotelle, Sylvie; Férard, Jean-François; Radetski, Claudemir M

2010-07-01

437

Raman amplification in terrestrial DWDM systems  

NASA Astrophysics Data System (ADS)

Raman amplification has been one of the enabling technologies employed to push the capacity x distance product in terrestrial DWDM systems. Due to its broad gain spectrum and the commercial availability of desired Raman pump wavelengths, more than 100-nm bandwidth is made possible covering the low loss window of silica fibers. In addition, distributed Raman amplification in transmission fibers and/or dispersion-compensating fibers (DCF) can significantly improve the system signal-to-noise ratio. In this talk, we will discuss the advantages and issues of Raman amplification, including pump-pump and pump-signal crosstalk, and their impact on the design of next generation fibers. Recent transmission experiments over Raman enabled fibers will be presented. Optimization of the system performance by allocating the Raman gains in co-, counter- and DCF-pumping will also be discussed.

Leng, Lufeng

2002-08-01

438

Terrestrial Laser Scanning for Vegetation Sampling  

PubMed Central

We developed new vegetation indices utilizing terrestrial laser scanning (TLS) to quantify the three-dimensional spatial configuration of plant communities. These indices leverage the novelty of TLS data and rely on the spatially biased arrangement of a TLS point cloud. We calculated these indices from TLS data acquired within an existing long term manipulation of forest structure in Central Oregon, USA, and used these data to test for differences in vegetation structure. Results provided quantitative evidence of a significant difference in vegetation density due to thinning and burning, and a marginally significant difference in vegetation patchiness due to grazing. A comparison to traditional field sampling highlighted the novelty of the TLS based method. By creating a linkage between traditional field sampling and landscape ecology, these indices enable field investigations of fine-scale spatial patterns. Applications include experimental assessment, long-term monitoring, and habitat characterization. PMID:25353981

Richardson, Jeffrey J; Moskal, L. Monika; Bakker, Jonathan D.

2014-01-01

439

Terrestrial nitrogen cycles: Some unanswered questions  

NASA Technical Reports Server (NTRS)

Nitrogen is generally considered to be the element which most often limits the growth of plants in both natural and agricultural ecosystems. It regulates plant growth because photosynthetic rates are strongly dependent on the concentration of nitrogen in leaves, and because relatively large mounts of protein are required for cell division and growth. Yet nitrogen is abundant in the biosphere - the well-mixed pool in the atmosphere is considered inexhaustible compared to biotic demand, and the amount of already fixed organic nitrogen in soils far exceeds annual plant uptake in terrestrial ecosystems. In regions where natural vegetation is not nitrogen limited, continuous cultivation induces nitrogen deficiency. Nitrogen loss from cultivated lands is more rapid than that of other elements, and nitrogen fertilization is generally required to maintain crop yield under any continuous system. The pervasiveness of nitrogen deficiency in many natural and most managed sites is discussed.

Vitousek, P.