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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

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

NASA Astrophysics Data System (ADS)

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

Arcidiancono, Antonio

3

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

NASA Technical Reports Server (NTRS)

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

Arcidiancono, Antonio

1990-01-01

4

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

5

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

6

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

E-print Network

Comparison of satellite-based evapotranspiration models over terrestrial ecosystems in China Yang: Evapotranspiration Eddy covariance Priestley­Taylor Penman­Monteith Evapotranspiration (ET) is a key component

Montana, University of

7

Trellis-coded CPM for satellite-based mobile communications  

NASA Technical Reports Server (NTRS)

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

Abrishamkar, Farrokh; Biglieri, Ezio

1988-01-01

8

Satellite based estimates of terrestrial water storage variations in Turkey  

NASA Astrophysics Data System (ADS)

In recent years, the Gravity Recovery and Climate Experiment (GRACE) has provided a new tool to study terrestrial water storage variations (TWS) at medium and large spatial scales, providing quantitative measures of TWS change. Linear trends in TWS variations in Turkey were estimated using GRACE observations for the period March 2003 to March 2009. GRACE showed a significant decrease in TWS in the southern part of the central Anatolian region up to a rate of 4 cm/year. The Global Land Data Assimilation System (GLDAS) model also captured this TWS decrease event but with underestimated trend values. The GLDAS model represents only a part of the total TWS variations, the sum of soil moisture (2 m column depth) and snow water equivalent, ignoring groundwater variations. Therefore, GLDAS model derived TWS variations were subtracted from GRACE derived TWS variations to estimate groundwater storage variations. Results revealed that decreasing trends of TWS observed by GRACE in the southern part of central Anatolia were largely explained by the decreasing trends of groundwater variations which were confirmed by the limited available well groundwater level data in the region.

Lenk, Onur

2013-07-01

9

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

10

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

11

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

2014-04-26

12

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

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

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

NASA Technical Reports Server (NTRS)

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

Horkin, Phil

1995-01-01

15

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

16

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

17

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

18

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

19

A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

20

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

21

Leo satellite-based telecommunication network concepts  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

22

Satellite-based terrestrial production efficiency modeling  

Microsoft Academic Search

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

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

2009-01-01

23

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

24

Spirapole antenna for communication systems utilizing both satellite and terrestrial assets  

Microsoft Academic Search

In this paper an antenna is presented that satisfies the two-fold radiation pattern requirement of communication systems utilizing both geostationary satellites and terrestrial transponders for coverage of mobile terminal away from the equator. A typical requirement for such a system is a low profile antenna that maximizes left-hand circularly polarized radiation in the satellite viewing angle, from 30° to 70°

Joseph S. Colburn; Jonathan J. Lynch; Adesunloye Obatoyinbo; Timothy Talty

2005-01-01

25

Wireless infrared communications for space and terrestrial applications  

NASA Technical Reports Server (NTRS)

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

Crimmins, James W.

1993-01-01

26

14 CFR 141.91 - Satellite bases.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Satellite bases. 141.91 Section 141.91...SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a pilot...chief instructor is designated for each satellite base, and that assistant chief...

2011-01-01

27

14 CFR 141.91 - Satellite bases.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

28

14 CFR 141.91 - Satellite bases.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Satellite bases. 141.91 Section 141.91...SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a pilot...chief instructor is designated for each satellite base, and that assistant chief...

2010-01-01

29

14 CFR 141.91 - Satellite bases.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Satellite bases. 141.91 Section 141.91...SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a pilot...chief instructor is designated for each satellite base, and that assistant chief...

2013-01-01

30

14 CFR 141.91 - Satellite bases.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Satellite bases. 141.91 Section 141.91...SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a pilot...chief instructor is designated for each satellite base, and that assistant chief...

2012-01-01

31

Study of terrestrial mobile systems for personal communications  

NASA Astrophysics Data System (ADS)

System configurations for the provision of satellite communication services to land mobiles in Europe are outlined. A network concept based on message store-and-forward switching techniques is proposed. The links work independently and the control function is distributed amongst the nodes. This gives good system flexibility, enhanced by baseband switching on board the satellite. The proposed system is realizable using short term developments of today's technology, but use of the INMARSAT space segment is a very attractive opportunity to set up at low cost a simplified and compatible demonstration system based on the same concept. Signal transmission techniques and mobile terminal technology are reviewed.

Baudu, J.; Morris, S.; Yongacoglu, A.

1984-11-01

32

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

33

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

34

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

35

Analysis of laser jamming to satellite-based detector  

NASA Astrophysics Data System (ADS)

The reconnaissance satellite, communication satellite and navigation satellite used in the military applications have played more and more important role in the advanced technique wars and already become the significant support and aid system for military actions. With the development of all kinds of satellites, anti-satellite laser weapons emerge as the times require. The experiments and analyses of laser disturbing CCD (charge coupled detector) in near ground have been studied by many research groups, but their results are not suitable to the case that using laser disturbs the satellite-based detector. Because the distance between the satellite-based detector and the ground is very large, it is difficult to damage it directly. However the optical receive system of satellite detector has large optical gain, so laser disturbing satellite detector is possible. In order to determine its feasibility, the theoretical analyses and experimental study are carried out in the paper. Firstly, the influence factors of laser disturbing satellite detector are analyzed in detail, which including laser power density on the surface of the detector after long distance transmission, and laser power density threshold for disturbing etc. These factors are not only induced by the satellite orbit, but dependence on the following parameters: laser average power in the ground, laser beam quality, tracing and aiming precision and atmospheric transmission. A calculation model is developed by considering all factors which then the power density entering into the detector can be calculated. Secondly, the laser disturbing experiment is performed by using LD (laser diode) with the wavelength 808 nm disturbing CCD 5 kilometer away, which the disturbing threshold value is obtained as 3.55×10-4mW/cm2 that coincides with other researcher's results. Finally, using the theoretical model, the energy density of laser on the photosensitive surface of MSTI-3 satellite detector is estimated as about 100mW/cm2, which is largely exceed the disturbing threshold and therefore verify the feasibility of using this kind of laser disturbing the satellite-based detector. According to the results. using the similar laser power density absolutely saturate the requirements to laser disturbing satellite-based detector. If considering the peak power of pulsed laser, even decrease laser average power, it is also possible to damage the detector. This result will provide the reliable evidences to evaluate the effect of laser disturbing satellite-based detector.

Wang, Si-wen; Guo, Li-hong; Guo, Ru-hai

2009-07-01

36

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

37

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

38

Impact of space weather events on satellite-based navigation  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

39

Design of Satellite-Based Networks for u-Health - GALENOS, DELTASS, MEDASHIP, EMISPHER  

Microsoft Academic Search

OP 2000 has implemented various satellite-based networks for telemedicine supporting the use of distributed medical intelligence. Such networks contribute to the improvement of the quality of medical care, to the cost-effective use of medical resources and to quick and reliable decisions. The high-end interactive video communication system WinVicos has been especially designed for telemedical applications like teleconsultation and second opinion

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

2007-01-01

40

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

41

Background light environment for free-space optical terrestrial communication links  

Microsoft Academic Search

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

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

2002-01-01

42

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

NASA Technical Reports Server (NTRS)

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

Paul, Lori (editor)

1991-01-01

43

Terrestrial communication experiments over various regions of Indian subcontinent and tuning of Hata's model  

Microsoft Academic Search

The development of various radio planning tools for the design of fixed and mobile communication systems requires radio channel\\u000a measurements, comparison with various models, and the tuning of various parameters involved in the model. Based on the various\\u000a land- and rail-based VHF\\/UHF measurements over northern, southern, western, and eastern parts of Indian subcontinent, the\\u000a parameters of Okumura–Hata model are tuned,

M. V. S. N. Prasad; K. Ratnamala; M. Chaitanya; P. K. Dalela

2008-01-01

44

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

NASA Astrophysics Data System (ADS)

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

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

2008-08-01

45

Satellite based permafrost modeling in low land tundra landscapes  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

46

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

47

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

48

Impact of satellite based PAR on estimates of terrestrial net primary productivity  

E-print Network

to estimate its magnitude. The productivity is controlled by the process of photosynthesis driven by solar carbon budget represents a balance between the exchanges of carbon among all the carbon reservoirs) is the rate at which plants capture and store atmospheric carbon dioxide (CO2) to generate oxygen and energy

Montana, University of

49

Satellite-based Monitoring of Environment for Human Security  

NASA Astrophysics Data System (ADS)

Global environmental change is emerging as the effect of transformation of the land, the ocean and the atmosphere driven by synergy of socio-economic and natural processes. As the progress of rapidly growing interconnectedness in the world, we have begun to induce the planetary scale change in our own life support system. Especially African environment is vulnerable to climate change and affecting human security in a broad sense. This paper describes needs for geoinformation and corresponding JAXA's satellite-based monitoring of environment.

Igarashi, Tamotsu

50

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.

51

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

DOEpatents

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

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

2011-12-13

52

Satellite-based studies on large-scale vegetation changes in China.  

PubMed

Remotely-sensed vegetation indices, which indicate the density and photosynthetic capacity of vegetation, have been widely used to monitor vegetation dynamics over broad areas. In this paper, we reviewed satellite-based studies on vegetation cover changes, biomass and productivity variations, phenological dynamics, desertification, and grassland degradation in China that occurred over the past 2-3 decades. Our review shows that the satellite-derived index (Normalized Difference Vegetation Index, NDVI) during growing season and the vegetation net primary productivity in major terrestrial ecosystems (for example forests, grasslands, shrubs, and croplands) have significantly increased, while the number of fresh lakes and vegetation coverage in urban regions have experienced a substantial decline. The start of the growing season continually advanced in China's temperate regions until the 1990s, with a large spatial heterogeneity. We also found that the coverage of sparsely-vegetated areas declined, and the NDVI per unit in vegetated areas increased in arid and semi-arid regions because of increased vegetation activity in grassland and oasis areas. However, these results depend strongly not only on the periods chosen for investigation, but also on factors such as data sources, changes in detection methods, and geospatial heterogeneity. Therefore, we should be cautious when applying remote sensing techniques to monitor vegetation structures, functions, and changes. PMID:22974506

Zhao, Xia; Zhou, Daojing; Fang, Jingyun

2012-10-01

53

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

54

Classification of satellite-based radio frequency transient recordings using sparse approximations over learned dictionaries  

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 occur in the presence of additive noise and structured clutter and appear as broadband nonlinear chirps at a receiver on-orbit due to ionospheric dispersion. 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 and potentially improve event discrimination capabilities for future satellite payloads. We extend two established dictionary learning algorithms, K-SVD and Hebbian, for use in classification of satellite RF data. Both algorithms allow us to learn features without relying on analytical constraints or additional knowledge about the expected signal characteristics. We use a pursuit search over the learned dictionaries to generate sparse classification features and discuss performance in terms of event classification using a nearest subspace classifier. We show a use of the two dictionary types in a mixed implementation to showcase algorithm distinctions in extracting discriminative information. We use principal component analysis to analyze and compare the learned dictionary spaces to the real data space, and we discuss some aspects of computational complexity and implementation.

Moody, Daniela I.; Smith, David A.

2014-01-01

55

Terrestrial sequestration  

ScienceCinema

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

Charlie Byrer

2010-01-08

56

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

57

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

58

Satellite-based monitoring of air quality within QUITSAT project  

NASA Astrophysics Data System (ADS)

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

di Nicolantonio, W.

2009-04-01

59

The use of satellite-based technology in developing countries  

E-print Network

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

Wood, Danielle Renee

2007-01-01

60

Mitigation of atmospheric effects on terrestrial FSO communication systems by using high-speed beam tracking antenna  

NASA Astrophysics Data System (ADS)

When a free-space optical beam propagates through the atmosphere it experiences deterioration and deformation of its wave-front caused from small scale, randomly localized changes in the atmospheric index of refraction. This results in beam wander and scintillation effects which can reduce the link availability and may introduce burst errors. This paper outlines experimental work on a free-space optical (FSO) communication system which connects an optical beam directly to a single-mode fiber (SMF) without any optical-to-electrical (O-E) conversion. In order to effectively couple the 1550 nm transmitted optical beam to a SMF it is necessary to be able to track and control the beam angle-of-arrival (AOA) changes. To achieve this, we have developed an optical antenna which uses a fine positioning mirror (FPM) capable of performing high-speed beam tracking and steering thus reducing to a great extent the optical power fluctuations of the received beam coupled to the SMF. This optical power fluctuation is partly a result of beam angle-of-arrival fluctuations caused by atmospheric turbulence. In our experiments we have tried to measure and quantify the magnitude of atmospheric turbulence experienced by an optical beam propagating through the atmosphere. First we demonstrate the relation between the AOA fluctuations and the frequency characteristics of the scintillation effects for a free-space optical beam propagating through a turbulent atmosphere. We use this information to determine the optimum antenna FPM tracking speed for improved performance and error free transmission. The results in the improved fiber received power as well as continuous error free transmission are presented.

Kazaura, Kamugisha; Omae, Kazunori; Suzuki, Toshiji; Matsumoto, Mitsuji; Sato, Takuro; Asatani, Koichi; Hatori, Mitsutoshi; Murakami, Tadaaki; Takahashi, Koichi; Matsumoto, Hideki; Wakamori, Kazuhiko; Arimoto, Yoshinori

2006-02-01

61

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

62

Operational Satellite-based Surface Oil Analyses (Invited)  

NASA Astrophysics Data System (ADS)

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

Streett, D.; Warren, C.

2010-12-01

63

Analysis of laser jamming to satellite-based detector  

Microsoft Academic Search

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

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

2009-01-01

64

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

65

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

NASA Astrophysics Data System (ADS)

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

Yilmaz, K. K.; Derin, Y.

2013-12-01

66

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

NASA Astrophysics Data System (ADS)

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

Yilmaz, Koray; Derin, Yagmur

2014-05-01

67

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

68

Satellite-based observations of surface turbulent stress during severe weather  

E-print Network

Satellite-based observations of surface turbulent stress during severe weather Mark A. Bourassa and a vertical offset (i.e., displacement height) of the log-wind profile, due to wave modification The environment of severe marine weather is harsh: in situ and satellite observations of surface turbulent

69

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

E-print Network

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

Pielke, Roger A.

70

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

E-print Network

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

Niyogi, Dev

71

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

E-print Network

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

Martin, Randall

72

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

73

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

74

A National Satellite-Based System for Providing Continuing Education to Engineers.  

ERIC Educational Resources Information Center

This document proposes, and indicates initial reaction to, a multi-point satellite-based delivery system which will permit expansion of current programs and services of the Association for Media-based Continuing Education for Engineers, Inc. (AMCEE) consortium to a much larger aggregated audience of practicing engineers throughout the country. It…

Georgia Inst. of Tech., Atlanta.

75

Evaluating Satellite-based Rainfall Estimates for Basin-scale Hydrologic Modeling  

Microsoft Academic Search

The reliability of any hydrologic simulation and basin outflow prediction effort depends primarily on the rainfall estimates. The problem of estimating rainfall becomes more obvious in basins with scarce or no rain gauges. We present an evaluation of satellite-based rainfall estimates for basin-scale hydrologic modeling with particular interest in ungauged basins. The initial phase of this study focuses on comparison

K. K. Yilmaz; T. S. Hogue; K. Hsu; H. V. Gupta; S. E. Mahani; S. Sorooshian

2003-01-01

76

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

Microsoft Academic Search

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

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

2005-01-01

77

Flight Trials of a Geostationary Satellite Based Augmentation System at High  

E-print Network

Flight Trials of a Geostationary Satellite Based Augmentation System at High Latitudes and for Dual flight demonstrations have taken place over the past few years to show how the Wide-Area Augmentation, flight tests were carried out to further show the possibilities of such a system to aviation. Some

Stanford University

78

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

E-print Network

is having strong resemblance to terrestrial GSM (Global System for Mobile communications) at the upper or the nature of multi-radios' communication. This paper aims to improve TCP communication performance in Mobile. Introduction Traditional terrestrial wireless or cellular networks provide mobile communication services

Sanyal, Sugata

79

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

80

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

81

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

82

Earth and the Terrestrial  

E-print Network

Earth and the Geology of the Terrestrial Planets (Bennett et al. Ch. 9) #12; Terrestrial planets Major Ideas In This Chapter #12;Terrestrial Planets (NASA) Compared to Jovian planets: ­ Smaller size or no moons ­ No rings #12;Planetary Surfaces and Interiors Terrestrial planets + Moon were similar when

Walter, Frederick M.

83

Satellite-Based Energy Balance for Mapping Evapotranspiration with Internalized Calibration (METRIC)—Model  

Microsoft Academic Search

Mapping evapotranspiration at high resolution with internalized calibration METRIC is a satellite-based image-processing model for calculating evapotranspiration ET as a residual of the surface energy balance. METRIC uses as its foundation the pioneering SEBAL energy balance process developed in The Netherlands by Bastiaanssen, where the near-surface temperature gradients are an indexed function of radiometric surface temperature, thereby eliminating the need

Richard G. Allen; Masahiro Tasumi; Ricardo Trezza

2007-01-01

84

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

USGS Publications Warehouse

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

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

2011-01-01

85

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

USGS Publications Warehouse

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

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

2011-01-01

86

Comparison of Historical Satellite Based Estimates of Solar Radiation Resources with Recent Rotating Shadowland Radiometer Measurements  

SciTech Connect

Satellite-based solar radiation estimates have recently been incorporated into the 1990-2005 update to the 1961-1990 U.S. National Solar Radiation Database (NSRDB). The National Aeronautics and Space Administration (NASA) also supplies satellite-based estimates of solar radiation. The usefulness of such data with respect to solar resources for site selection and designing solar energy conversion systems is often questioned. 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. We compare the most recent shadowband radiometer MMDT with a complement of thermopile 'first class' solar radiometers at one site. Quantitative analysis shows that in most cases, the long-term average MMDT and measured data are comparable, within 10% of each other for global, and 20% for direct-radiation MMDT.

Myers, D.

2009-01-01

87

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

Code of Federal Regulations, 2014 CFR

...ancillary terrestrial component of Mobile Satellite Services. 1...Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE...ancillary terrestrial component of Mobile Satellite Services. (a...purpose of this subpart, a Mobile Satellite Service...

2014-10-01

88

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

Code of Federal Regulations, 2011 CFR

...ancillary terrestrial component of Mobile Satellite Services. 1...Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE...ancillary terrestrial component of Mobile Satellite Services. (a...purpose of this subpart, a Mobile Satellite Service...

2011-10-01

89

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

Code of Federal Regulations, 2012 CFR

...ancillary terrestrial component of Mobile Satellite Services. 1...Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE...ancillary terrestrial component of Mobile Satellite Services. (a...purpose of this subpart, a Mobile Satellite Service...

2012-10-01

90

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

Code of Federal Regulations, 2013 CFR

...ancillary terrestrial component of Mobile Satellite Services. 1...Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE...ancillary terrestrial component of Mobile Satellite Services. (a...purpose of this subpart, a Mobile Satellite Service...

2013-10-01

91

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

92

Comparison of INMARSAT and ATS3 satellite communication  

SciTech Connect

There exists a need to provide communication through a satellite- based network which allows a user to communicate from a remote site to a fixed site. This discussion provides a comparison, both technical and financial, between the existing ATS3 satellite system and the commercial INMARSAT system. This comparison identified the limitations of each system to provide various types of communication.

Not Available

1993-03-29

93

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

94

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

95

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

96

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

Microsoft Academic Search

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

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

2008-01-01

97

Electromagnetic Waves Attenuation due to Rain: A Prediction Model for Terrestrial or L.O.S SHF and EHF Radio Communication Links  

Microsoft Academic Search

Because of the interest raised for SHF and EHF radio communications, the attenuation of electromagnetic waves by rain will\\u000a always constitute a major concern for telecommunication engineers and scientists. The rain attenuation prediction models exposed\\u000a in literature calculate the attenuation related to a given rain rate or else to a given percentage of time. The new model\\u000a proposed in this

Fidèle Moupfouma

2009-01-01

98

Communication  

Microsoft Academic Search

\\u000a In 1964, Marshall McLuhan, sociologist and contemporary thinker wrote in Understanding Media: The Extensions of Man that the dominant communication media of our time will shape the way humans think, act and ultimately perceive the world\\u000a around them. “The media are extensions of our senses; as they change, they utterly transform our environment and affect everything\\u000a we do, they “massage”

William F. Bria; Nancy B. Finn

99

Low cost call delivery for roamers of satellite based mobile systems  

Microsoft Academic Search

In the third generation of mobile systems several satellite systems are expected to be integrated with the terrestrial cellular network. A number of roles of satellites have been defined within third generation of mobile systems, for example, providing UNITS (universal mobile telecommunication systems) services in area lacking in terrestrial facilities, providing services to aeronautical users etc. This paper deals with

Nidhi Agrawal

1999-01-01

100

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

101

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

102

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

103

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

NASA Astrophysics Data System (ADS)

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

Shen, Yan; Chen, Zhuoqi

2013-04-01

104

Evaluation of Clear Sky Models for Satellite-Based Irradiance Estimates  

SciTech Connect

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

Sengupta, M.; Gotseff, P.

2013-12-01

105

Agreements between ground-based and satellite-based observations. [of earth magnetospheric currents  

NASA Technical Reports Server (NTRS)

The polar ionospheric parameters obtained by the meridian chain of magnetometers are compared with those obtained by satellites, and a number of ionospheric quantities including the distribution of the electric potential, field-aligned currents, ionospheric currents and their equatorial counterparts, and the relationship between the AE index and the cross-polar cap potential is determined. It is noted that the agreement observed between the ground-based and satellite-based results allows to reduce the search for the driving mechanism of the ionospheric Pedersen current to identifying the driving mechanism of the Pedersen counterpart current in the equatorial plane.

Akasofu, S.-I.; Weimer, D.; Iijima, T.; Ahn, B.-H.; Kamide, Y.

1990-01-01

106

APPLICATION OF TERRESTRIAL LASER SCANNING FOR SHIPBUILDING  

Microsoft Academic Search

Recently, a laser scanner technology has been receiving more attention. Nowadays use of terrestrial laser scanners (TLS) is continuously increasing. This technique offers the possibility of measuring millions of points within short period of time. Thus, it is possible to record complete 3D objects efficiently. In this communication the process followed to model the hull and the deck of the

K. Biskup; P. Arias; H. Lorenzo; J. Armesto

2007-01-01

107

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.

108

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

109

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

110

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

111

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

112

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

113

Comparison of two satellite-based rainfall algorithms using pacific atoll raingage data  

SciTech Connect

Rainfall estimates for two simple satellite-based rainfall algorithms are verified over the tropical Pacific using a new method that incorporates sparsely distributed raingages. The resulting linear regression relationship between monthly areal rainfall and the highly reflective cloud index agrees with earlier results. However, the GOES precipitation index (GPI), which was calibrated using radar rainfall data obtained from the eastern tropical Atlantic, produces biased areal rainfall estimates over most of the tropical Pacific. However, its precision is greater than the highly reflective cloud index, perhaps due to the GPI's larger spatial dimensions. With the incorporation of calibration coefficients determined in this study. the GPI will produce unbiased estimates of areal rainfall for the tropical Pacific region.

Morrissey, M.L. (Univ. of Hawaii, Honolulu (United States)); Greene, J.S. (Univ. of Delaware, Newark (United States))

1993-02-01

114

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

115

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

NASA Astrophysics Data System (ADS)

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

Liu, Zhong

2014-11-01

116

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

117

Terrestrial Analogs to Mars  

Microsoft Academic Search

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. These studies include field workshops, characterization of terrestrial analog sites, instrument tests,

T. G. Farr; S. Arcone; R. W. Arvidson; V. Baker; N. G. Barlow; D. Beaty; M. S. Bell; D. D. Blankenship; N. Bridges; G. Briggs; M. Bulmer; F. Carsey; S. M. Clifford; R. A. Craddock; P. W. Dickerson; N. Duxbury; G. L. Galford; J. Garvin; J. Grant; J. R. Green; T. K. P. Gregg; E. Guinness; V. L. Hansen; M. H. Hecht; J. Holt; A. Howard; L. P. Keszthelyi; P. Lee; P. D. Lanagan; R. C. F. Lentz; D. W. Leverington; L. Marinangeli; J. E. Moersch; P. A. Morris-Smith; P. Mouginis-Mark; G. R. Olhoeft; G. G. Ori; P. Paillou; J. F. Reilly II; J. W. Rice Jr.; C. A. Robinson; M. Sheridan; K. Snook; B. J. Thomson; K. Watson; K. Williams; K. Yoshikawa

2002-01-01

118

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

119

TERRESTRIAL ECOSYSTEM SIMULATOR  

EPA Science Inventory

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

120

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.

121

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

Microsoft Academic Search

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

Hideki Kobayashi; Nicolas Delbart; Rikie Suzuki; Keiji Kushida

2010-01-01

122

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 in the Western North Atlantic E. Boss, D. Swift, L. Taylor, P. Brickley, R. Zaneveld, S. Riser, M.J. Perry, Maine 04469 Dana Swift and Steve Riser School of Oceanography, University of Washington, Seattle

123

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 ...

124

Comment on ``Assessing interannual variability of evapotranspiration at the catchment scale using satellite-based evapotranspiration data  

E-print Network

Comment on ``Assessing interannual variability of evapotranspiration at the catchment scale using satellite-based evapotranspiration data sets'' by Lei Cheng et al. Jozsef Szilagyi1,2 Received 20 October on ``Assessing interannual variability of evapotranspiration at the catchment scale using satellite

Szilagyi, Jozsef

125

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

Microsoft Academic Search

One of the biggest obstacles for the average Earth science student today is locating and obtaining satellite- based remote sensing datasets in a format that is accessible and optimal for their data analysis needs. At the Goddard Earth Sciences Data and Information Services Center (GES-DISC) alone, on the order of hundreds of Terabytes of data are available for distribution to

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

2008-01-01

126

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

127

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...

128

Satellite-based high latitude snow volume trend, variability and1 contribution to sea level over 1989/20062  

E-print Network

is a key driver of the sea level41 seasonal cycle, but net snow volume trend for the Pan Arctic regions1 Satellite-based high latitude snow volume trend, variability and1 contribution to sea level over the snow volume exhibits a statistically32 significant negative trend (-9.7±3.8 km3 .year-1 , p-value=0

Boyer, Edmond

129

Integrating field and high spatial resolution satellite-based methods for monitoring shallow submersed aquatic habitats in the Sound of  

E-print Network

Cover Integrating field and high spatial resolution satellite-based methods for monitoring shallow habitat and meet the requirements for monitoring on a routine basis. Remote sensing from satellites spectral resolution, particularly with respect to bands in the blue-green region of the visible spectrum

130

A Theoretical Framework for Analyzing Satellite-based Web Multicasting Marios Dikaiakos  

E-print Network

to grow fur- ther with the rise of Internet usage [2, 17] and the advent of new Web-based applications, these loads are difficult to meet; in the future, if Web use continues to grow as fast, systems and networks with Web content, without overloading their terrestrial links. Web multicasting works as follows: satellite

Pallis, George

131

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

132

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

PubMed Central

Background: The effect of ambient air pollution on global variations and trends in asthma prevalence is unclear. Objectives: Our goal was to investigate community-level associations between asthma prevalence data from the International Study of Asthma and Allergies in Childhood (ISAAC) and satellite-based estimates of particulate matter with aerodynamic diameter < 2.5 µm (PM2.5) and nitrogen dioxide (NO2), and modelled estimates of ozone. Methods: We assigned satellite-based estimates of PM2.5 and NO2 at a spatial resolution of 0.1° × 0.1° and modeled estimates of ozone at a resolution of 1° × 1° to 183 ISAAC centers. We used center-level prevalence of severe asthma as the outcome and multilevel models to adjust for gross national income (GNI) and center- and country-level sex, climate, and population density. We examined associations (adjusting for GNI) between air pollution and asthma prevalence over time in centers with data from ISAAC Phase One (mid-1900s) and Phase Three (2001–2003). Results: For the 13- to 14-year age group (128 centers in 28 countries), the estimated average within-country change in center-level asthma prevalence per 100 children per 10% increase in center-level PM2.5 and NO2 was –0.043 [95% confidence interval (CI): –0.139, 0.053] and 0.017 (95% CI: –0.030, 0.064) respectively. For ozone the estimated change in prevalence per parts per billion by volume was –0.116 (95% CI: –0.234, 0.001). Equivalent results for the 6- to 7-year age group (83 centers in 20 countries), though slightly different, were not significantly positive. For the 13- to 14-year age group, change in center-level asthma prevalence over time per 100 children per 10% increase in PM2.5 from Phase One to Phase Three was –0.139 (95% CI: –0.347, 0.068). The corresponding association with ozone (per ppbV) was –0.171 (95% CI: –0.275, –0.067). Conclusion: In contrast to reports from within-community studies of individuals exposed to traffic pollution, we did not find evidence of a positive association between ambient air pollution and asthma prevalence as measured at the community level. PMID:22548921

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

2012-01-01

133

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

134

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

NASA Technical Reports Server (NTRS)

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

Jasinski, Michael; Eastman, Joseph; Borak, Jordan

2010-01-01

135

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

136

The OHIO concept: Refinements on a design for satellite-based measurements of stratospheric OH  

SciTech Connect

Current atmospheric measurement strategies by both NASA and ESA include the development of a technique to measure the global climatology of stratospheric OH, because of its central importance in stratospheric ozone balance. The OH Interferometer Observations (OHIO) concept is an option for the generalized far infrared Fabry-Perot instrument, optimized for satellite-based measurement of the OH radical in the earth`s stratosphere with the simplest possible instrument configuration. This paper gives refined design parameters for OHIO. The design presented uses entirely existing, demonstrated technology, does not require stored cryogens, and concentrates on thermal emission measurements of OH, the one stratospheric species which can be measured uniquely and well in the far infrared from a satellite. Measurements are of the F{sub 1}, 7/2{sup +} {yields} F{sub 1}, 5/2{sup {minus}} transition at 118.455 cm{sup {minus}1} (84.42 {micro}m), which has been demonstrated to be the best spectral feature for atmospheric measurements of OH. The current design parameters, including realistic values for Fabry-Perot transmission, detector performance, and filtering required to suppress radiation passed in the higher orders of the grating monochromator, are demonstrated to be within a factor of four of what is required for global measurements of OH. Thus, with modest further improvements in detector performance and spectrometer design, the authors may soon be able to demonstrate a working concept for a potential satellite instrument.

Chance, K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Wijnbergen, J.J.; Valk, P. de [Space Research Organization of the Netherlands, Groningen (Netherlands). Lab. for Space Research; Schneider, W. [German Aerospace Research Center, Oberpfaffenhofen (Germany). German Remote Sensing Data Center; Burrows, J.P. [Univ. of Bremen (Germany). Inst. for Remote Sensing

1995-12-31

137

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

138

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

139

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

140

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

141

Terrestrial Impact Structures  

NASA Astrophysics Data System (ADS)

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

Grieve, R. A. F.

142

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

143

Primordial Terrestrial Xenon Revisited  

NASA Astrophysics Data System (ADS)

Xenon solar wind composition revealed by Genesis matches mathematically derived primordial terrestrial xenon with high precision, except for 136Xe and 134Xe. This can be explained by modification of fission yields in open systems.

Meshik, A. P.; Pravdivtseva, O. V.; Hohenberg, C. M.

2014-09-01

144

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

145

Dietary characterization of terrestrial mammals.  

PubMed

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

Pineda-Munoz, Silvia; Alroy, John

2014-08-22

146

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

147

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

148

Non-cooperative collision avoidance concept for Unmanned Aircraft System using satellite-based radar and radio communication  

Microsoft Academic Search

Rapidly increasing growth and demand in various Unmanned Aircraft Systems (UAS) have pushed governmental regulation development and numerous technology research activities toward integrating unmanned and manned aircraft into the same civil airspace. Safety of other airspace users is the primary concern; thus, with the introduction of UAS into the National Airspace System (NAS), a key issue to overcome is the

Ming-Shih Huang; Ram M. Narayanan

2011-01-01

149

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

150

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

151

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

NASA Astrophysics Data System (ADS)

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

Mikuš, Petra; Strelec Mahovi?, Nataša

2013-04-01

152

Validation of satellite-based CI detection of convective storms via backward trajectories  

NASA Astrophysics Data System (ADS)

Within this study, the rapid development and evolution of several severe convective events is investigated based on geostationary satellite images, and is related to previous findings on suitable detection thresholds for convective initiation. Nine severe events have been selected that occurred over Central Europe in summer 2012, and have been classified into the categories supercell, mesoscale convective system, frontal system and orographic convection. The cases are traced backward starting from the fully developed convective systems to its very beginning initial state using ECMWF data with 0.5 degree spatial resolution and 3h temporal resolution. For every case the storm life cycle was quantified through the storm's infrared (IR) brightness temperatures obtained from Meteosat Second Generation SEVIRI with 5 min temporal resolution and 4.5 km spatial resolution. In addition, cloud products including cloud optical thickness, cloud phase and effective droplet radius have been taken into account. A semi-automatic adjustment of the tracks within a search box was necessary to improve the tracking accuracy and thus the quality of the derived life-cycles. The combination of IR brightness temperatures, IR temperature time trends and satellite-based cloud products revealed different stages of storm development such as updraft intensification and glaciation well in most casesconfirming previously developed CI criteria from other studies. The vertical temperature gradient between 850 and 500 hPa, the Total-Totals-Index and the storm-relative helicity have been derived from ECMWF data and were used to characterize the storm synoptic environment. The results suggest that the storm-relative helicity also influences the life time of convective storms over Central Europe confirming previous studies. Tracking accuracy has shown to be a crucial issue in our study and a fully automated approach is required to enlarge the number of cases for significant statistics.

Dietzsch, Felix; Senf, Fabian; Deneke, Hartwig

2013-04-01

153

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

154

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

155

An improved satellite-based approach for estimating vapor pressure deficit from MODIS data  

NASA Astrophysics Data System (ADS)

Vapor pressure deficit (VPD) is an important variable widely used in ecosystem and climate models. In this paper, an improved satellite-based approach to estimating VPD was presented that uses several remote sensing products coupled with field measured data. The proposed method exploits an optimized algorithm to derive near-surface actual vapor pressure (ea) from Moderate Resolution Imaging Spectroradiometer (MODIS) data and upgrades Smith's (1966) methodology for estimating ea. The proposed new algorithm for calculating ea was evaluated against in situ measurements at 119 validation sites in China for 2 months in 2013. The mean absolute error (MAE) and root-mean-square error (RMSE) were less than 0.25 kPa and 0.33 kPa, respectively. The near-surface air temperature (Ta), which is an important input data for calculating VPD, was estimated from satellite-retrieved land surface temperature, and had an RMSE of less than 2.5 K. The estimated VPD values were validated with ground observation data from the Heihe River Basin for 5 months in 2012 and for all of China for August 2013. A coefficient of determination (R2) of 0.912, MAE of 0.27 kPa, and RMSE value of 0.32 kPa were achieved for the 2012 test data, and corresponding values of 0.88, 0.278 kPa, and 0.367 kPa for the 2013 test data. These results are promising, especially considering the comparatively high spatial resolution (1 km) of the VPD map estimated from the satellite data. Potential applications include global evapotranspiration estimation, fire warning, and vegetation analysis.

Zhang, Hongmei; Wu, Bingfang; Yan, Nana; Zhu, Weiwei; Feng, Xueliang

2014-11-01

156

Categorizing natural disaster damage assessment using satellite-based geospatial techniques  

USGS Publications Warehouse

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

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

2008-01-01

157

Ground- and satellite-based evidence of the biophysical mechanisms behind the greening Sahel.  

PubMed

After a dry period with prolonged droughts in the 1970s and 1980s, recent scientific outcome suggests that the decades of abnormally dry conditions in the Sahel have been reversed by positive anomalies in rainfall. Various remote sensing studies observed a positive trend in vegetation greenness over the last decades which is known as the re-greening of the Sahel. However, little investment has been made in including long-term ground-based data collections to evaluate and better understand the biophysical mechanisms behind these findings. Thus, deductions on a possible increment in biomass remain speculative. Our aim is to bridge these gaps and give specifics on the biophysical background factors of the re-greening Sahel. Therefore, a trend analysis was applied on long time series (1987-2013) of satellite-based vegetation and rainfall data, as well as on ground-observations of leaf biomass of woody species, herb biomass, and woody species abundance in different ecosystems located in the Sahel zone of Senegal. We found that the positive trend observed in satellite vegetation time series (+36%) is caused by an increment of in situ measured biomass (+34%), which is highly controlled by precipitation (+40%). Whereas herb biomass shows large inter-annual fluctuations rather than a clear trend, leaf biomass of woody species has doubled within 27 years (+103%). This increase in woody biomass did not reflect on biodiversity with 11 of 16 woody species declining in abundance over the period. We conclude that the observed greening in the Senegalese Sahel is primarily related to an increasing tree cover that caused satellite-driven vegetation indices to increase with rainfall reversal. PMID:25400243

Brandt, Martin; Mbow, Cheikh; Diouf, Abdoul A; Verger, Aleixandre; Samimi, Cyrus; Fensholt, Rasmus

2015-04-01

158

A satellite-based assessment of transpacific transport of pollution aerosol  

NASA Astrophysics Data System (ADS)

It has been well documented that pollution and dust from east Asia can be transported across the North Pacific basin, reaching North America and beyond. In this study, we assess the transpacific transport of "pollution aerosol" (defined as a mixture of aerosols from urban/industrial pollution and biomass burning) by taking advantage of the much improved measurement accuracy and enhanced new capabilities of satellite sensors in recent years. A 4-year (2002 to 2005) climatology of optical depth for pollution aerosol was generated from Moderate Resolution Imaging Spectroradiometer (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/a pollution aerosol is exported from east Asia to the northwestern Pacific Ocean, of which about 25% reaches the west coast of North America. The imported flux of 4.4 Tg/a to North America is equivalent to about 15% of local emissions from the United States and Canada. 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, largely because of record intense Eurasia boreal forest fires in spring and summer. The overall uncertainty of pollution fluxes is estimated at a factor of 2. 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 latitude-integrated fluxes, with larger model-satellite differences in latitudinal and seasonal variations of fluxes.

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

2008-07-01

159

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

160

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

161

A Near Real-Time Monitoring System for NWP Forecast and Satellite-Based Products  

NASA Astrophysics Data System (ADS)

A data repository for collocated model forecasts and simulations and in-situ observations for Surface Fluxes Analysis (SurFA) project has been established at the US National Climatic Data Center (NCDC; www.ncdc.noaa.gov/thredds/surfa.html), which is also one of the data centers for the National Oceanic and Atmospheric Administration (NOAA)'s satellite and other climate data. The SurFA project is initiated by the World Climate Research Program (WCRP) Working Groups on Numerical Experimentation and on the Surface Fluxes (WGNE and WGSF), Observation & Assimilation Panel (WOAP), and the Ocean Observation Panel for Climate (OOPC) to evaluate the performance of high-resolution global Numerical Weather Prediction (NWP) forecast variables and satellite-based products used in computing surface fluxes such as surface winds against high quality in-situ observations. SPEC is a satellite product evaluation system that is developed at NCDC and designed to facilitate the integrated operational monitoring of NOAA's satellite and modeling systems and products. Currently, it has the capability of ingesting data via various types of data servers, co- locating fields in time and space of various data formats, and providing users with various data output formats including NetCDF format and basic analysis and visualization functionality. A prototype has been developed utilizing the existing capability and functionality of SPEC and the SurFA datasets to monitor the performance of NWP short-range forecast winds and satellite-derived winds by identifying potential outliers in near real-time and in an automatic fashion. An end-to-end system design and data flow will be outlined along with examples of its applications and future improvement. Such a system can be readily applied to other model variables.

Vasquez, L.; Peng, G.; Urzen, M.; Hankins, B.; Zhang, H.

2012-12-01

162

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

163

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

164

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

165

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

166

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

SciTech Connect

The fraction of photosynthetically active radiation intercepted by vegetation, F(sub ipar) is an important parameter for modeling the interactions between the land-surface and atmosphere and for estimating vegetation biomass productivity. This study was, therefore, an integral part of FIFE. The specific purpose of this experiment was to find out how well definitive measurements of F(sub ipar) on the ground relate to near-ground and satellite based spectral reflectance measurements. Concurrent measurements of F(sub ipar) and ground, helicopter, and satellite based reflectance measurements were taken at thirteen tall-grass prairie sites within the FIFE experimental area. The sites were subjected to various combinations of burning and grazing managements. The ground and helicopter based reflectance measurements were taken on the same day or few days from the time of the overpass of LANDSAT and SPOT satellites. Ground-based reflectance measurements and sun photometer readings taken at the times of the satellite overpasses were used to correct for atmospheric attenuation. Hand-held radiometer spectral indices were strongly correlated with helicopter and satellite based values (r = 0.94 for helicopter, 0.93 for LANDSAT Thematic Mapper, and 0.86 for SPOT). However, the ground, helicopter, and satellite based normalized difference spectral vegetation indices showed low sensitivity to changes in F(sub ipar). Reflectance measurements were only moderately well correlated with measurements of F(sub ipar) (r = 0.82 for hand-held radiometer, 0.84 for helicopter measurements, and 0.75 for the LANDSAT Thematic Mapper and SPOT). Improved spectral indices which can compensate for site differences are needed in order to monitor F(sub ipar) more reliably. 12 refs.

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

1992-11-01

167

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

168

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

169

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

Microsoft Academic Search

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

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

2010-01-01

170

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

NASA Astrophysics Data System (ADS)

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

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

2005-10-01

171

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

172

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

173

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

174

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

175

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

1997-05-01

176

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

177

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

178

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

179

GLOBAL TERRESTRIAL CARBON CYCLE  

EPA Science Inventory

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

180

[Bites by terrestrial vertebrates].  

PubMed

Bites by terrestrial vertebrates, reptiles or mammals, represent a special risk in tropical regions. Envenomation is possible by a few lizards and many snakes. For mammals, tissular destructions due to the bite can be severe. Whatever is the offending animal, bites can further become infected by transmitted viruses or bacteria. PMID:10992781

Henry, F; Martalo, O; Claessens, N; Piérard, G E

2000-06-01

181

Terrestrial planet formation  

PubMed Central

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

Righter, K.; O’Brien, D. P.

2011-01-01

182

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

183

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

184

Terrestrial photovoltaic measurement procedures  

NASA Technical Reports Server (NTRS)

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

1977-01-01

185

The Terrestrial Planet Finder  

Microsoft Academic Search

The Terrestrial Planet Finder (TPF) is a space-based astronomical telescope that will combine high sensitivity and spatial resolution to detect and characterize ~150 planetary systems within 15 pc of our Sun. In a five-year mission, currently expected to commence in 2012, TPF will look for the atmospheric signatures of life using the methods of planetary spectroscopy. This is only possible

Peter R. Lawson

2001-01-01

186

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

187

The baseband processor in future satellite communication systems  

NASA Technical Reports Server (NTRS)

This paper provides a description of a baseband processor planned for satellite communication systems operating in Ka band. The satellite based interconnection of individual earth terminals is described in terms of uplink and downlink message formats, and the on-board processing signal flow. Advanced technology requirements and developments are reviewed including current activity in custom large scale integrated circuit development.

Thomas, R. E.; Carroll, D. R.

1984-01-01

188

Conformal phased array with beam forming for airborne satellite communication  

Microsoft Academic Search

For enhanced communication on board of aircraft novel antenna systems with broadband satellite-based capabilities are required. The installation of such systems on board of aircraft requires the development of a very low-profile aircraft antenna, which can point to satellites anywhere in the upper hemisphere. To this end, phased array antennas which are conformal to the aircraft fuselage are attractive. In

H. Schippers; J. Verpoorte; P. Jorna; A. Hulzinga; A. Meijerink; C. G. H. Roeloffzen; R. G. Heideman; A. Leinse; M. Wintels

2008-01-01

189

The baseband processor in future satellite communication systems  

NASA Astrophysics Data System (ADS)

This paper provides a description of a baseband processor planned for satellite communication systems operating in Ka band. The satellite based interconnection of individual earth terminals is described in terms of uplink and downlink message formats, and the on-board processing signal flow. Advanced technology requirements and developments are reviewed including current activity in custom large scale integrated circuit development.

Thomas, R. E.; Carroll, D. R.

190

An overview of satellite-based tele-education activities in Canada  

NASA Astrophysics Data System (ADS)

An overview of the major Canadian tele-educational activities is presented. The need for tele-educational services in a country as large as Canada is outlined. The Access network of the Alberta Educational Communications Corporation is described. The educational radio services in Canada are outlined. The cost effectiveness of tele-education in Canada is evaluated.

Kerr, W. T.; Kawashima, Junichi

1989-05-01

191

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

192

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

193

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

194

PERSONAL HAND-HELD COMMUNICATIONS VIA L-BAND CDMA-BASED GEOSTATIONARY BEAMFORMING  

E-print Network

-band frequencies. For compatibility with the terrestrial CDMA standard, the communication model is based on the IS communications around the world has been phenomenal, as personal communications has become an integral part coverage of terrestrial cellular communication systems in the southern half of Canada, a CDMA

Blostein, Steven D.

195

Making More Terrestrial Planets  

Microsoft Academic Search

The results of 16 new 3D N-body simulations of the final stage of the formation of the terrestrial planets are presented. These N-body integrations begin with 150–160 lunar-to-Mars size planetary embryos, with semi-major axes 0.3

J. E. Chambers

2001-01-01

196

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

197

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

198

Integrating ground-based EO data in satellite-based systems  

SciTech Connect

Earth observation (EO) and other forms of geo-referenced data are typically thought of as being ``satellite data.`` It is true that the majority of EO data are satellite oriented; thus, most on-line EO data systems are designed primarily for satellite image data. However, there is A small but significant minority of EO data that is not satellite image data; i.e., it is ground-based or terrestrial data Unfortunately, many on-line systems designed for satellite data do not take into account the somewhat different nature of associated ground-based data, Data queries that work most of the time but fail because the system has not taken into account less common data are not robust enough for today`s users. In order to avoid embarrassing problems, EO system designers must be aware of the nature of ground- based data. In this paper we describe some of our insights on this subject in the hope that the designers of other systems may learn from our experience.

Jennings, S.V.; Daugherty, P.; Yow, T.G.

1997-02-01

199

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

200

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

201

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

202

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

203

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

204

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

205

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

NASA Technical Reports Server (NTRS)

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

Calio, A. J.

1979-01-01

206

Reconfigurable Antennas for High Data Rate Multi-beam Communication Systems  

NASA Technical Reports Server (NTRS)

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

Bernhard, Jennifer T.; Michielssen, Eric

2005-01-01

207

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

208

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

209

Solar structure and terrestrial weather  

NASA Technical Reports Server (NTRS)

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

Wilcox, J. M.

1976-01-01

210

Low Earth Orbit satellite/terrestrial mobile service compatibility  

NASA Technical Reports Server (NTRS)

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

Sheriff, Ray E.; Gardiner, John G.

1993-01-01

211

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.

212

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

213

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

214

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

NASA Astrophysics Data System (ADS)

Following 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

215

1, 167193, 2004 Terrestrial carbon  

E-print Network

BGD 1, 167­193, 2004 Terrestrial carbon budget at country-scale I. A. Janssens et al. Title Page Biogeosciences Discussions is the access reviewed discussion forum of Biogeosciences The carbon budget.janssens@ua.ac.be) 167 #12;BGD 1, 167­193, 2004 Terrestrial carbon budget at country-scale I. A. Janssens et al. Title

Paris-Sud XI, Université de

216

Terrestrial Planet Atmospheres and Biosignatures  

Microsoft Academic Search

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

V. Meadows; S. Seager

2010-01-01

217

Terrestrial Planet Geophysics  

NASA Astrophysics Data System (ADS)

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

Phillips, R. J.

2008-12-01

218

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

NASA Astrophysics Data System (ADS)

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

Löwe, Peter; Wächter, Joachim

2013-04-01

219

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

EPA Science Inventory

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

220

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

221

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

NASA Astrophysics Data System (ADS)

One of the biggest obstacles for the average Earth science student today is locating and obtaining satellite- based remote sensing datasets in a format that is accessible and optimal for their data analysis needs. At the Goddard Earth Sciences Data and Information Services Center (GES-DISC) alone, on the order of hundreds of Terabytes of data are available for distribution to scientists, students and the general public. The single biggest and time-consuming hurdle for most students when they begin their study of the various datasets is how to slog through this mountain of data to arrive at a properly sub-setted and manageable dataset to answer their science question(s). The GES DISC provides a number of tools for data access and visualization, including the Google-like Mirador search engine and the powerful GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni) web interface. Giovanni provides a simple way to visualize, analyze and access vast amounts of satellite-based Earth science data. Giovanni's features and practical examples of its use will be demonstrated, with an emphasis on how satellite remote sensing can help students understand recent events in the atmosphere and biosphere. Giovanni is actually a series of sixteen similar web-based data interfaces, each of which covers a single satellite dataset (such as TRMM, TOMS, OMI, AIRS, MLS, HALOE, etc.) or a group of related datasets (such as MODIS and MISR for aerosols, SeaWIFS and MODIS for ocean color, and the suite of A-Train observations co-located along the CloudSat orbital path). Recently, ground-based datasets have been included in Giovanni, including the Northern Eurasian Earth Science Partnership Initiative (NEESPI), and EPA fine particulate matter (PM2.5) for air quality. Model data such as the Goddard GOCART model and MERRA meteorological reanalyses (in process) are being increasingly incorporated into Giovanni to facilitate model- data intercomparison. A full suite of data analysis and visualization tools is also available within Giovanni. The GES DISC is currently developing a systematic series of training modules for Earth science satellite data, associated with our development of additional datasets and data visualization tools for Giovanni. Training sessions will include an overview of the Earth science datasets archived at Goddard, an overview of terms and techniques associated with satellite remote sensing, dataset-specific issues, an overview of Giovanni functionality, and a series of examples of how data can be readily accessed and visualized.

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

2008-12-01

222

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

223

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

224

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

225

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 ...

226

USING TERRESTRIAL PLANTS IN BIOMONITORING  

EPA Science Inventory

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

227

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

228

GEOLogic: Terrestrial and Jovian Planets  

NSDL National Science Digital Library

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

Laura Guertin

229

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

NASA Astrophysics Data System (ADS)

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

Turk, F. Joseph; Xian, Peng

2013-03-01

230

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

231

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

232

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

233

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

234

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

Microsoft Academic Search

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

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

2008-01-01

235

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

236

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

237

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

238

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

239

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

240

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

241

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

242

Terrestrial ecosystems and climatic change  

SciTech Connect

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

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

1990-01-01

243

Utilization of the terrestrial cyanobacteria  

NASA Astrophysics Data System (ADS)

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

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

244

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

245

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

NASA Astrophysics Data System (ADS)

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

Robinson, D.; Maggi, B.

2003-04-01

246

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

247

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

248

Swimming with robots: Human robot communication at depth  

Microsoft Academic Search

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

Bart Verzijlenberg; Michael Jenkin

2010-01-01

249

Accumulation of the terrestrial planets  

Microsoft Academic Search

A review is conducted of the current status of theoretical and numerical research on the accumulation of the terrestrial planets. The growth of planets is considered, taking into account the road to rapid accretion and giant protoplanets and the slow road to planetary formation by continual sweeping up of small bodies by larger ones. It is found possible to gain

G. W. Wetherill

1978-01-01

250

Terrestrial atmosphere, water and astrobiology  

Microsoft Academic Search

Primitive life, defined as a chemical system capable to transfer its molecular information via self-replication and also capable to evolve, originated about 4 billion years ago from the processing of organic molecules by liquid water. Terrestrial atmosphere played a key role in the process by allowing the permanent presence of liquid water and by participating in the production of carbon-based

A. Brack; M. Coradini

2010-01-01

251

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

252

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....

253

Carbon dioxide and terrestrial ecosystems  

Microsoft Academic Search

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

G. W. Koch; H. A. Mooney

1996-01-01

254

Solar Variability and Terrestrial Climate  

NASA Astrophysics Data System (ADS)

The thermal conditions on Planet Earth are primarily the function of the energy in- put from the Sun. The variations in climate on Planet Earth is, however, primarily the function of the redistribution and reorganisation of the internal terrestrial heat balance. Solar variability may affect terrestrial climate (1) by direct changes in irradiance, a fac- tor, however, which is known to be very small, (2) by the solar wind interaction with the geomagnetic field increasing and decreasing the shielding capacity to infalling cosmic-ray, which is known to affect the formation of clouds thereby also affecting global terrestrial climat, and (3) by the solar wind interaction with the geomagnetic field leading to changes in the EarthSs rate of rotation which affect ocean and atmo- sphere circulation thereby also affecting global climate (and sea level). INTAS Project 97-301008 concerns the interaction between geomagnetic field changes and global climatic changes. No doubts, we see important links between externally and internally driven changes in the EarthSs geomagnetic field and changes in terrestrial climate.

Mörner, N.-A.

255

Ionospheres of the terrestrial planets  

Microsoft Academic Search

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

R. W. Schunk; A. F. Nagy

1980-01-01

256

NEON Airborne Remote Sensing of Terrestrial Ecosystems  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

257

CARBON DIOXIDE SEQUESTRATION IN TERRESTRIAL ECOSYSTEMS  

EPA Science Inventory

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

258

Formation of the terrestrial planets from planetesimals  

NASA Technical Reports Server (NTRS)

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

Wetherill, George W.

1991-01-01

259

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

260

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

E-print Network

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

Hansen, Andrew J.

261

Dissolved Organic Carbon in Terrestrial Ecosystems: Synthesis  

E-print Network

to aquatic ecosystems. De- spite their importance for terrestrial and aquatic biogeochemistry, these fluxes fluxes associated with primary productivity or heterotro- phic respirations in terrestrial systems (for transport from terrestrial environments repre- sents a substantial component of the ecosystem C balance

Neff, Jason

262

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

263

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

Microsoft Academic Search

Development of network models that reflect true end-to-end architectures such as the Transformational Communications Architecture need to encompass terrestrial, wireless and satellite component to truly represent all of the complexities in a world wide communications network. Use of best-in-class tools including OPNET, Satellite Tool Kit (STK), Popkin System Architect and their well known XML-friendly definitions, such as OPNET Modeler's Data

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

2004-01-01

264

The formation of terrestrial planets  

NASA Astrophysics Data System (ADS)

Previous numerical simulations of the process of formation of the terrestrial planets led to results which typically have two problems: (i) the final orbits of the planets are too eccentric and inclined relative to the real orbits of the terrestrial planet system and (ii) the planets form too slowly with respect to the time indicated by the Hf-W chronometer for the Earth-Moon system. It is usually thought that these problems are due to the fact that the simulations do not account for a population of small planetesimals carrying cumulatively a mass comparable to the mass of the planetary embryos. We have done new simulations, starting with a system of 25 Mars-mass embryos initially distributed from 0.5 to 4 AU, embedded in a disk of 2.5 Earth masses of planetesimals, modeled with 1,000 individual equal-mass particles. We have performed 8 simulations. 4 simulations assumed Jupiter and Saturn initially on their current orbits, while the remaining 4 simulations assumed that the two giant planets had circular orbits, consistent with the `Nice model' on the origin of the late heavy bombardment (Gomes et al., 2005) and on the giant planets' orbital architecture (Tsiganis et al., 2005). The simulations starting with Jupiter on an eccentric orbit lead to the formation of a system of terrestrial planets whose angular momentum deficit is 7 times smaller than that obtained in previous simulations (Chambers, 2001), whereas the formation timescale is three times shorter. This confirms that the dynamical friction exerted by planetesimals onto the forming planets is an essential ingredient in terrestrial planet formation. Interestingly, the final terrestrial planets achieved in these simulations are dynamically colder than the real terrestrial planets. The simulations starting with Jupiter on a circular orbit still produce planets which are slightly too dynamically excited (by about 50%) and which form too slowly (by a factor of 2). These problems are expected to disappear in future simulations modeling the planetesimal disk with a larger number of particles, or accounting for the regeneration of planetesimals during giant collisions among embryos. A main difference between the planets formed in the eccentric Jupiter case with respect to the circular Jupiter case is that the former do not acquire a significant amount of mass from beyond 2.5 AU. These planets are therefore expected to be more deficient in water, possibly too dry with respect to the Earth.

Morbidelli, A.; O'Brien, D.

265

Evaluation of GRACE data using terrestrial gravity observations  

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

266

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

267

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.

268

Signalling characteristics in satellite-aided land mobile communications  

NASA Technical Reports Server (NTRS)

The feasibility of land mobile radio communications has been demonstrated by a large number of experiments with NASA's ATS satellites. Significant differences in the propagation characteristics of satellite and terrestrial mobile signal paths were observed in the experiments. Terrestrial paths are best in cities where they can provide frequency reuse and assure communication by bouncing signals around obstructions. Satellites may be best in thinly populated areas because they eliminate the need for many tower mounted relays. The satellite paths do not have the severe Rayleigh fading that limits the range and signal quality of terrestrial paths if the satellite is above approximately ten degrees elevation, a value easily achieved for the United States. The experiments verified that high quality voice communications and other functions, such as data transmission and vehicle position surveillance, are easily accomplished through geostationary satellites with vehicle transmitter power and antenna gain no different than those of terrestrial mobile communications.

Anderson, R. E.

1982-01-01

269

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

270

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

271

Operating a terrestrial Internet router onboard and alongside a small satellite  

E-print Network

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

Wood, Lloyd

272

Alien Terrestrial Invertebrates of Europe  

Microsoft Academic Search

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

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

273

NASA's Terrestrial Planet Finder Missions  

NASA Technical Reports Server (NTRS)

NASA has decided to move forward with two complementary Terrestrial Planet Finder (TPF) missions, a visible coronagraph and an infrared formation flying interferometer. These missions are major missions in the NASA Office of Space Science Origins Theme. The primary science objectives of the TPF missions are to search for, detect, and characterize planets and planetary systems beyond our own Solar System, including specifically Earth-like planets.

Coulter, Daniel R.

2004-01-01

274

Recent geographic variations in terrestrial carbon cycle based on new production efficiency model  

NASA Astrophysics Data System (ADS)

The terrestrial carbon budget must be understood more accurately for the prediction of future changes in climate and carbon cycle. The goal of this study is to estimate spatial and temporal patterns of the carbon fluxes more accurately using the newly developed terrestrial biosphere model and satellite data. Our model consists of terrestrial carbon cycle and hydrology submodels. An advantage is a new approach in the LUE (Light Use Efficiency) concept, which calculates temperature and water stress factor in LUE model from a photosynthetic model and stomatal conductance formulation. In carbon cycle model, GPP is calculated from the LUE concept and satellite-based fPAR dataset. The soil carbon cycle model is based on CENTURY model with optimized water and temperature factor. Hydrological submodel is based on BIOME3, calculating ET is used by Penman-Monteith method. The model was run for 18 years (1982-1999) on a global scale, and we simulated the geographic distributions of the terrestrial carbon fluxes. We have checked simulated vegetation growth limiting factor with stress factor of MODIS NPP algorithm. Large differences were found in the northern mid and high latitude forests because soil moisture stress is not incorporated into MODIS NPP algorithm. Although responses of stress factors in MODIS NPP algorithm are mostly similar to our theoretically based one, our model works well in the soil moisture limited regions. Global total NPP was estimated at 61.7GtC/yr, and total NEP variations are strongly related with ENSO. Validation using measured values from the GPPDI database showed that our NPP estimation was within a reasonable range. The temporal patterns of the terrestrial carbon flux showed that NPP increased in the northern middle/high latitudes, central Africa, and India. In contrast, NPP decreased in the south Amazon region, the middle latitudes of the southern hemisphere, a part of North America, and Southeast Asia. Sensitivity analysis indicated that NPP variations were largely affected by fAPAR, solar radiation, temperature, and precipitation variations. Our new model was shown to be an appropriate tool to estimate the spatial and temporal patterns of the terrestrial carbon fluxes.

Sasai, T.; Ichii, K.; Yamaguchi, Y.

2003-12-01

275

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

276

Natural organobromine in terrestrial ecosystems  

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

277

Arsenic speciation of terrestrial invertebrates.  

PubMed

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. PMID:19673270

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

2009-07-01

278

Comparative Climatology of Terrestrial Planets  

NASA Astrophysics Data System (ADS)

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

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

279

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

280

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

281

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

NASA Astrophysics Data System (ADS)

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

Buhe, Aosier

282

A Satellite-based Approach to Evaluate the Impact of Land Use Change on Recharge Rates in the Southern High Plains  

NASA Astrophysics Data System (ADS)

A conceptual satellite-based ecohydrological modelling approach was used to evaluate the impact of land use changes on recharge rates in the Southern High Plains. Spatially-distributed recharge rates were estimated as the residual between mean annual values of precipitation (MAP) and evapotranspiration (ET). Evapotranspiration is computed pixel-by-pixel according to the positive/negative anomalies observed between the actual vegetation productivity and an expected rainfall-dependent productivity value. Both anomalies, positive and negative, define a dual-domain of ET-excess and recharge conditions, respectively, in which annual ET is assumed to be linearly correlated with local precipitation and the vegetation productivity anomaly. The Enhanced Vegetation Index (EVI) from MODIS/Terra was used as a surrogate for vegetation productivity and a regional EVI-MAP relationship was built using topographic and land cover criteria to obtain the expected rainfall-dependent productivity values. A time-series of the EVI product (2000-2009), a 60 m digital elevation model and mean annual precipitation maps from the PRISM database were integrated into a Geographic Information System and used as inputs to the model. The ability of the satellite-based approach to estimate ET and recharge rates was tested against independent estimates of recharge and ET rates derived from unsaturated chloride soil profiles and Large Aperture Scintillometer measurements, respectively. Results were spatially combined and differences in recharge rates among representative land cover types (drylands, natural rangelands and, rain-fed and irrigated areas) were highlighted and discussed.

Contreras López, S.; Gowda, P. H.; Scanlon, B. R.; Jobbagy, E. G.; Alcaraz-Segura, D.; Reedy, R. C.

2009-12-01

283

Intersatellite quantum communication feasibility study  

NASA Astrophysics Data System (ADS)

The shift in the Communication paradigm from the bit to the qubit is increasingly exploited in terrestrial long range links and networks, with strong potentials in secure communications, quantum computing and metrology. The space-to-ground quantum key distribution was also considered as feasible. A new different scenario for the quantum communications is that of the intersatellite link. In this study we focus on the extension of intersatellite communications into the quantum domain. The long distances involved and the fast relative motion are severe constraints, partially compensated by the absence of beam degradation due to the propagation in the atmosphere as well as the relatively low background noise level. We address the conception of the optical terminal and the predicted performances in the case of constellations of LEO and MEO satellite including the quantum communications and quantum teleportation.

Tomaello, Andrea; Dall'Arche, Alberto; Naletto, Giampiero; Villoresi, Paolo

2011-08-01

284

Cadaver decomposition in terrestrial ecosystems  

NASA Astrophysics Data System (ADS)

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

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

2007-01-01

285

Cadaver decomposition in terrestrial ecosystems.  

PubMed

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

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

2007-01-01

286

The Laboratory for Terrestrial Physics  

NASA Technical Reports Server (NTRS)

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

2003-01-01

287

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

288

Information -Communication Communication des entreprises  

E-print Network

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

Sart, Remi

289

Chemical Communication in Peracarid Crustaceans  

Microsoft Academic Search

\\u000a Chemical communication plays an important role during the life of peracarid crustaceans, where the two main taxa, the amphipods\\u000a and isopods, have representatives in both aquatic and terrestrial habitats. As in other crustaceans, the antennae bear the\\u000a most important chemosensory structures, which are used for food-finding, predator detection and intraspecific interactions.\\u000a The chemical nature of peracarid pheromones is unknown, but

Martin Thiel

290

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

291

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

292

Automatic building modeling from terrestrial laser scanning  

E-print Network

hard to recover 3D building structures from 2D image. Recent studies ([2] [6]) show that laser scanning imagery, airborne and terrestrial laser scanning give explicit 3D information, which enables the rapidAutomatic building modeling from terrestrial laser scanning Shi Pu International Institute for Geo

Pu, Shi

293

Abundance of Terrestrial Planets by Microlensing  

E-print Network

Terrestrial planets may be detected using the gravitational microlensing technique. This was demonstrated in the high magnification event MACHO-98-BLG-35. Observing strategies aimed at measuring the abundance of terrestrial planets are discussed, using both existing telescopes and planned telescopes.

Philip Yock

2000-04-04

294

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

295

Terrestrial atmosphere, water and astrobiology  

NASA Astrophysics Data System (ADS)

Primitive life, defined as a chemical system capable to transfer its molecular information via self-replication and also capable to evolve, originated about 4 billion years ago from the processing of organic molecules by liquid water. Terrestrial atmosphere played a key role in the process by allowing the permanent presence of liquid water and by participating in the production of carbon-based molecules. Water molecules exhibit specific properties mainly due to a dense network of hydrogen bonds. The carbon-based molecules were either home made in the atmosphere and/or in submarine hydrothermal systems or delivered by meteorites and micrometeorites. The search for possible places beyond the earth where the trilogy atmosphere/water/life could exist is the main objective of astrobiology. Within the Solar System, exploration missions are dedicated to Mars, Europa, Titan and the icy bodies. The discovery of several hundreds of extrasolar planets opens the quest to the whole Milky Way.

Brack, A.; Coradini, M.

2010-12-01

296

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

297

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

298

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

299

Line following terrestrial insect biobots.  

PubMed

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

Latif, Tahmid; Bozkurt, Alper

2012-01-01

300

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

301

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

302

Extreme Terrestrial Gamma ray Events  

NASA Astrophysics Data System (ADS)

Terrestrial gamma ray flashes were first discovered by the Compton GRO observatory and such event have been observed later on-board Rhessi satellite and more recently by the Fermi and Agile missions. These events are believed to be associated with the thunderstorm activity in the lower atmosphere. When observed from the satellite instruments, the observed time structure. Shows short milliseconds bursts probably due to lightning discharges , however an other type of long bursts with a duration of a few seconds to a few minutes have been observed only in the lower atmosphere. Such behaviour is natural as the upward moving photons go through a large atmospheric depth several 100 gms which will affect both the time structure and the spectral nature as the thunderstorms normally originate only in the lower troposphere just above the convective boundary layer. We report the observations of extreme terrestrial gamma ray events with time duration ~150-250 min observed during the thunderstorm activity in Hyderabad South, India. At 17.3o lat. and 78.6o long., Hyderabad is located in the convergence zone with high level of thunderstorm activity during the monsoon period. Spectral data suggest a continuum flux of the gamma ray from 100 keV to 10 MeV for hours. Temporal characteristics studied with time resolution of 100 microsec do not show any excess power density at any frequency. The data suggest that unlike gamma ray flashes which are generated just during the lightening flash, large electric field disturbances during long thunderstorm activity may lead to large flux of accelerated particles, which emit continuum gamma rays flux.

Manchanda, R. K.; Kamble, Nilima

2012-07-01

303

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.

304

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

305

Spacelab communications experiments  

NASA Technical Reports Server (NTRS)

The Space Shuttle launched Spacelab is planned to provide the communications community with a platform to develop the technology required for NASA's and DOD's missions, and future domestic and international communications satellites in the 1980s. The Laboratory, with a weight carrying capability of 14,500 kg into a low-earth orbit and return to earth, is being planned to carry laser telescopes; large (greater-than 10 meter) deployable antennas; spaceborne receivers to map terrestrial noise sources in a variety of frequency bands, and other advanced technology applicable to the 1980s and 1990s. Spacelab will also facilitate ease of comparative testing between alternative or competing experiments, subsystems and components prior to a commitment to an automated satellite.

Ehrlich, E.

1974-01-01

306

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

307

Communication availability enhancement of hybrid systems through exploitation of media diversity: evaluation of HF and satellite communication impairment mechanisms  

Microsoft Academic Search

Diversity schemes have been developed to enable HF systems to recover from media-specific disturbances, and fade margins are typically applied to ameliorate the effects of fading on satellite communication links. In this paper we describe a hybrid system concept comprised of an L-band Satcom and a terrestrial HF communication system. We examine the synergy which exists between these media in

John M. Goodman; John W. Ballard; Eugene Sharp

1996-01-01

308

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

309

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

310

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

311

A new communication paradigm for mobile TV over cellular network Dr. Hongxiang Li  

E-print Network

A new communication paradigm for mobile TV over cellular network Dr. Hongxiang Li Electrical terrestrial TV network and propose a new mobile TV communication paradigm that is radically different from and communication theory (i.e., Network Coding and Dirty Paper Coding) in the new mobile TV system design. Despite

312

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

313

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

314

ACEEE International Journal on Communication, Vol 1, No. 1, Jan 2010 2010 ACEEE  

E-print Network

) for providing wireless telecommunication and broadband communication services. Comparisons of HAPs, satellite tall antenna mast or a very Low-Earth-Orbit (LEO) satellite [4]. This modern communication solution has advantages of both terrestrial and satellite communications [4, 5, 6]. It is a good technique for serving

Paris-Sud XI, Université de

315

Solar-Terrestrial Weather Relations.  

NASA Astrophysics Data System (ADS)

The factors mitigating against a short term response of tropospheric circulation systems, of the type claimed by Wilcox et al. (1974), to solar activity are reviewed. The dilemma posed by Wilcox's analyses may be resolved by following Hines in making a clear distinction between cause and effect and thereby allowing that the troposphere itself may actively participate in creating the observed signal. A variant of Wilcox's Vorticity Area Index is suggested. This variant allows us to critically examine the conclusions of Williams (1978) and Williams and Gerety (1980) concerning the significance of the correlation claimed by Wilcox et al. Their conclusions are thereby reversed, with the result being a confirmation of the idea introduced by Halevy (1978) concerning the candidacy of baroclinic instability for providing a means by which the troposphere might participate in producing the solar-terrestrial weather correlation. A sequence of simple one-dimensional linear dynamical models are analysed in order to directly test this hypothesis. It is first demonstrated through analysis of the wave mechanics of barotropic instability that such disturbances are not inevitably trapped in the vicinity of the shear maximum. The barotropic problem supports a sequence of long wavelength radiating modes through the mechanism of critical level overreflection. A similar detailed analysis of more complicated one-dimensional baroclinic instability problems establishes a similar modal structure in that the fundamental "Charney" mode is inevitably accompanied in realistic models by a sequence of resonant undertones which are generally referred to as Green modes. If there were a mechanism by which the Green modes could be made growth-rate competitive with the Charney modes then their evolution in the troposphere could be strongly affected by direct solar influence on the upper stratosphere and mesosphere and we would have the basis of an explicit model of the mechanism by which the correlation between solar and terrestrial weather is established. Several attempts to effect such an increase of importance of the Green modes are discussed, no one of which is completely satisfactory but each of which is suggestive of avenues worthy of further investigation.

Halevy, Itamar

316

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

317

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

318

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

319

Steroidal saponins from Tribulus terrestris.  

PubMed

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

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

2014-11-01

320

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

321

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

322

Terrestrial Mobile Mapping: photogrammetric simulator  

NASA Astrophysics Data System (ADS)

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

Taglioretti, C.; Manzino, A. M.

2014-08-01

323

Terrestrial Planet Finder: science overview  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

324

Terrestrial cooling and solar variability  

NASA Technical Reports Server (NTRS)

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

Agee, E. M.

1982-01-01

325

Complete experimental toolbox for alignment-free quantum communication  

NASA Astrophysics Data System (ADS)

Quantum communication employs the counter-intuitive features of quantum physics for tasks that are impossible in the classical world. It is crucial for testing the foundations of quantum theory and promises to revolutionize information and communication technologies. However, to execute even the simplest quantum transmission, one must establish, and maintain, a shared reference frame. This introduces a considerable overhead in resources, particularly if the parties are in motion or rotating relative to each other. Here we experimentally show how to circumvent this problem with the transmission of quantum information encoded in rotationally invariant states of single photons. By developing a complete toolbox for the efficient encoding and decoding of quantum information in such photonic qubits, we demonstrate the feasibility of alignment-free quantum key-distribution, and perform proof-of-principle demonstrations of alignment-free entanglement distribution and Bell-inequality violation. The scheme should find applications in fundamental tests of quantum mechanics and satellite-based quantum communication.

D'Ambrosio, Vincenzo; Nagali, Eleonora; Walborn, Stephen P.; Aolita, Leandro; Slussarenko, Sergei; Marrucci, Lorenzo; Sciarrino, Fabio

2012-07-01

326

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

327

The solar photon thruster as a terrestrial pole sitter.  

PubMed

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

Matloff, Gregory L

2004-05-01

328

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

329

Architectures and protocols for an integrated satellite-terrestrial mobile system  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

330

Rain induced attenuation prediction model for terrestrial and satellite-Earth microwave links  

Microsoft Academic Search

At microwave frequencies, rain is the main cause of degradation of the performances of satellite and terrestrial communications\\u000a systems, essentially in tropical zones. The design and implementation of such systems involve the knowledge of the propagation\\u000a parameters which govern link availability and service quality. Thus it seems desirable to develop prediction methods for deriving\\u000a approximate attenuation statistics for any microwave

Fidele Moupfouma

1987-01-01

331

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

332

The development of early terrestrial ecosystems  

E-print Network

In this review of terrestrialization by plants and animals in the early Phanerozoic, the classical idea of a major mid-Palaeozoic event is discarded in favour of gradual colonization over a long time period. Four phases ...

Selden, Paul A.; Edwards, Dianne

1993-01-01

333

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

334

DEVELOPMENT OF SCALING CRITERIA FOR TERRESTRIAL MICROCOSMS  

EPA Science Inventory

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

335

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...

336

Recommended architectures for the Terrestrial Planet Finder  

NASA Technical Reports Server (NTRS)

The primary conclusion from an intensive, two year period of study is that with suitable technology investment, starting now, a mission to detect terrestrial planets around nearby stars could be launched within a decade.

Beichman, C.

2004-01-01

337

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

338

THE EFFECT OF CLOUD FRACTION ON THE RADIATIVE ENERGY BUDGET: The Satellite-Based GEWEX-SRB Data vs. the Ground-Based BSRN Measurements  

NASA Astrophysics Data System (ADS)

The NASA GEWEX-SRB (Global Energy and Water cycle Experiment - Surface Radiation Budget) project produces and archives shortwave and longwave atmospheric radiation data at the top of the atmosphere (TOA) and the Earth's surface. The archive holds uninterrupted records of shortwave/longwave downward/upward radiative fluxes at 1 degree by 1 degree resolution for the entire globe. The latest version in the archive, Release 3.0, is available as 3-hourly, daily and monthly means, spanning 24.5 years from July 1983 to December 2007. Primary inputs to the models used to produce the data include: shortwave and longwave radiances from International Satellite Cloud Climatology Project (ISCCP) pixel-level (DX) data, cloud and surface properties derived therefrom, temperature and moisture profiles from GEOS-4 reanalysis product obtained from the NASA Global Modeling and Assimilation Office (GMAO), and column ozone amounts constituted from Total Ozone Mapping Spectrometer (TOMS), TIROS Operational Vertical Sounder (TOVS) archives, and Stratospheric Monitoring-group's Ozone Blended Analysis (SMOBA), an assimilation product from NOAA's Climate Prediction Center. The data in the archive have been validated systemically against ground-based measurements which include the Baseline Surface Radiation Network (BSRN) data, the World Radiation Data Centre (WRDC) data, and the Global Energy Balance Archive (GEBA) data, and generally good agreement has been achieved. In addition to all-sky radiative fluxes, the output data include clear-sky fluxes, cloud optical depth, cloud fraction and so on. The BSRN archive also includes observations that can be used to derive the cloud fraction, which provides a means for analyzing and explaining the SRB-BSRN flux differences. In this paper, we focus on the effect of cloud fraction on the surface shortwave flux and the level of agreement between the satellite-based SRB data and the ground-based BSRN data. The satellite and BSRN employ different measuring methodologies and thus result in data representing means on dramatically different spatial scales. Therefore, the satellite-based and ground-based measurements are not expected to agree all the time, especially under skies with clouds. The flux comparisons are made under different cloud fractions, and it is found that the SRB-BSRN radiative flux discrepancies can be explained to a certain extent by the SRB-BSRN cloud fraction discrepancies. Apparently, cloud fraction alone cannot completely define the role of clouds in radiation transfer. Further studies need to incorporate the classification of cloud types, altitudes, cloud optical depths and so on.

Zhang, T.; Stackhouse, P. W.; Gupta, S. K.; Cox, S. J.; Mikovitz, J. C.; Nasa Gewex Srb

2011-12-01

339

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

340

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

341

Update on terrestrial ages of Antarctic meteorites  

SciTech Connect

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

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

2000-01-14

342

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

343

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

NASA Astrophysics Data System (ADS)

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

Hossain, F.

2013-12-01

344

An automated benchmarking infrastructure to support operational delivery of a satellite-based evapotranspiration product for Australia (the ET-ICE project)  

NASA Astrophysics Data System (ADS)

Infrastructure was developed to allow satellite-based evapotransipration products to be compared and evaluated against independent observations at different temporal and spatial scales. The infrastructure is based on data representation standards that enable highly automated operation and is being used in the Evapotranspiration product Inter-Comparison and Evaluation (ET-ICE) project. The project has assembled operational or near-operational gridded ET products for Australia and evaluates these for their suitability as part of an operational ET product to be delivered for the whole continent by the Australian Bureau of Meteorology Water Division. To meet the specifications for the operational product, minimum requirements are monthly time step, 5km resolution, full coverage over Australia for the period 2000-2005, and potential to support an operational data service. Currently seven ET products (some with multiple variants) are being assessed, including products based on remotely sensed land surface temperature, satellite reflectance measurements, the MODIS Leaf Area Index product, or simulated by land surface models. The flexibility of the infrastructure means that new (or revised) products and validation data are easily added. The infrastructure enables objective benchmarking and improvement of operational products, and could be easily adapted for other spatio-temporal satellite products.

King, Edward

2010-05-01

345

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

346

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

347

Communication skills.  

PubMed

The front-line nurse is responsible for providing direct patient care, patient satisfaction, care coordination, policy, safety, and communication during a 12-hour shift. Every nurse has the opportunity to make a positive impact on patient outcomes through day-to-day advocacy for patients, nurses, and the nursing profession. Communication is a means of advocacy that provides the avenue to which a positive impact can be made. There are multiple barriers to effective communication in the day-to-day communication of the front-line nurse. Interprofessional communication and shared governance models offer ways to improve communication within nursing and within a systems approach. PMID:25680486

Ellison, Deborah

2015-03-01

348

Predictability of the terrestrial carbon cycle.  

PubMed

Terrestrial ecosystems sequester roughly 30% of anthropogenic carbon emission. However this estimate has not been directly deduced from studies of terrestrial ecosystems themselves, but inferred from atmospheric and oceanic data. This raises a question: to what extent is the terrestrial carbon cycle intrinsically predictable? In this paper, we investigated fundamental properties of the terrestrial carbon cycle, examined its intrinsic predictability, and proposed a suite of future research directions to improve empirical understanding and model predictive ability. Specifically, we isolated endogenous internal processes of the terrestrial carbon cycle from exogenous forcing variables. The internal processes share five fundamental properties (i.e., compartmentalization, carbon input through photosynthesis, partitioning among pools, donor pool-dominant transfers, and the first-order decay) among all types of ecosystems on the Earth. The five properties together result in an emergent constraint on predictability of various carbon cycle components in response to five classes of exogenous forcing. Future observational and experimental research should be focused on those less predictive components while modeling research needs to improve model predictive ability for those highly predictive components. We argue that an understanding of predictability should provide guidance on future observational, experimental and modeling research. PMID:25327167

Luo, Yiqi; Keenan, Trevor F; Smith, Matthew

2015-05-01

349

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

350

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

NASA Astrophysics Data System (ADS)

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

Riffler, Michael; Wunderle, Stefan

2013-04-01

351

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

352

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

353

A Possible Aeronomy of Extrasolar Terrestrial Planets  

E-print Network

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

W. A. Traub; K. W. Jucks

2002-05-22

354

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

355

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

356

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

357

Communicating Science  

USGS Publications Warehouse

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

Farris, Gaye S.

2005-01-01

358

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

359

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

360

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

361

Responses of terrestrial aridity to global warming  

NASA Astrophysics Data System (ADS)

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

Fu, Qiang; Feng, Song

2014-07-01

362

Magnetic reconnection in the terrestrial magnetosphere  

SciTech Connect

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

Feldman, W.C.

1984-01-01

363

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

364

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

365

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

366

Facilitating communications  

Microsoft Academic Search

How often have you felt that the person you were talking to was speaking another language? How often have others seemed bewildered when you described something? We may attribute this to technical jargon or new terminology, but the problem more likely stems from basic communication failure. Since effective communication is essential to a project's success, learning to communicate successfully should

P. L. Ferdinandi

1998-01-01

367

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

368

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

NASA Astrophysics Data System (ADS)

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

Xu, Lingzhe; Yang, Shihai

2010-07-01

369

Terrestrial ecosystem feedbacks to global climate change  

Microsoft Academic Search

Anthropogenic greenhouse gases are expected to induce changes in global climate that can alter ecosystems in ways that, in turn, may further affect climate. Such climate-ecosystem interactions can generate either positive or negative feedbacks to the climate system, thereby either enhancing or diminishing the magnitude of global climate change. Important terrestrial feedback mechanisms include COâ fertilization (negative feedbacks), carbon storage

Daniel A. Lashof; Benjamin J. DeAngelo; Scott R. Saleska; John Harte

1997-01-01

370

Using observational data to evaluate global terrestrial  

E-print Network

to model land-atmosphere carbon exchange #12;Terrestrial Biospheric Models Well-informed Carbon cycle #12;Models Well-informed Carbon cycle projections Input data Initial conditions Parameter values Atmosphere Coupled Land Models Coupled carbon-climate models disagree on the continued strength of the net

371

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

372

Carbohydrate formation in rewetted terrestrial cyanobacteria  

Microsoft Academic Search

In the terrestrial cyanobacterium Nostoc commune Vauch. formation of carbohydrate polymers was measured upon rewetting the mats in a light-dark regime. To discriminate between carbohydrates of different physiological function, total carbohydrate was determined as anthrone-reactive material (ARM) and storage carbohydrate (glycogen) assayed by an enzymic test. In the dry thalli glycogen was found to represent less than one tenth of

A. Ernst; T.-W. Chen; P. Böger

1987-01-01

373

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

374

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.

375

Ammonia transport by terrestrial and aquatic insects  

Microsoft Academic Search

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

Dirk Weihrauch; Andrew Donini; Michael J. O’Donnell

376

Modelling the Eccentricities of the Terrestrial Planets  

Microsoft Academic Search

Numerical models of late-stage planet formation have successfully reproduced a number of the observed characteristics of the terrestrial planets. However, understanding the origin of their orbital eccentricities remains a problem. Earth and Venus currently have very low orbital eccentricities: roughly 0.03 when averaged over long timescales. In general, numerical simulations of planetary accretion produce Earth analogues with significantly larger eccentricities,

J. Chambers

2003-01-01

377

Neutron production in terrestrial gamma ray flashes  

Microsoft Academic Search

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

B. E. Carlson; N. G. Lehtinen

2010-01-01

378

First RHESSI terrestrial gamma ray flash catalog  

Microsoft Academic Search

We present a summary of data from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) terrestrial gamma ray flash (TGF) catalog. We describe the RHESSI search algorithm and discuss its limitations due to its design emphasis on cleanliness rather than completeness. This search algorithm has identified 820 TGFs between March of 2002 and February of 2008. Radiation damage to

B. W. Grefenstette; D. M. Smith; B. J. Hazelton; L. I. Lopez

2009-01-01

379

Terrestrial Accretion from the Solar Wind  

Microsoft Academic Search

MR. HARRISON has raised a number of important issues which can only be answered tentatively at the present time. Presumably the oxygen is liberated from terrestrial rocks by solar ultra-violet radiation, and an estimate of the mean quantum efficiency of this photochemical process should be readily obtainable in the laboratory, by irradiation of outgassed rock samples in an evacuated chamber,

C. M. de. Turville

1961-01-01

380

Some Studies of Terrestrial Impact Cratering Rate  

Microsoft Academic Search

In 1984, a 28.4 Myr periodicity was detected in the ages of terrestrial impact craters and a 26 Myr periodicity in the epochs of mass extinctions of species. Periodic comet showers from the Oort cloud seemed to cause catastrophic events linked to mass extinctions of species. Our first study revealed that the only significant detected periodicity is the ``human signal''

L. Jetsu

2011-01-01

381

UV-B EFFECTS ON TERRESTRIAL ECOSYSTEMS  

EPA Science Inventory

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

382

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

383

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

384

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...

385

Connecting terrestrial to celestial reference frames  

NASA Astrophysics Data System (ADS)

In this paper we outline several problems related to the realization of the international celestial and terrestrial reference frames - the ICRF and ITRF - at the millimeter level of accuracy, with emphasis on ICRF issues. We consider here the current status of the ICRF, the interrelationship between the ICRF and ITRF, and considerations for future ICRF realizations.

Malkin, Z.

2015-03-01

386

ESTUARINE WETLANDS (CHAPTER: TERRESTRIAL VEGETATION OF CALIFORNIA)  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

387

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

388

Internal structure of massive terrestrial planets  

Microsoft Academic Search

Planetary formation models predict the existence of massive terrestrial planets and experiments are now being designed that should succeed in discovering them and measuring their masses and radii. We calculate internal structures of planets with one to ten times the mass of the Earth (Super-Earths) to obtain scaling laws for total radius, mantle thickness, core size and average density as

Diana Valencia; Richard J. O'Connell; Dimitar D. Sasselov

2006-01-01

389

Subsolidus convective cooling histories of terrestrial planets  

Microsoft Academic Search

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

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

1979-01-01

390

Terrestrial Planet Formation in the ? Centauri System  

Microsoft Academic Search

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

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

2002-01-01

391

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

392

New Directions for the NOAA Solar and Terrestrial Physics Division  

NASA Astrophysics Data System (ADS)

To a large degree the Solar and Terrestrial Physics (STP) Division within the NOAA National Geophysical Data Center has been historically viewed as a final reposition for solar-geophysical data acquired from providers around the world. This perception was mostly due to STP's participation as a World Data Center (WDC) for Solar-Terrestrial Physics (Boulder) within the International Council for Science (ICSU). As such, STP was responsible for the archive, access and assessment of diverse collections of space environmental data collected worldwide, including data from the former Soviet Union and other "non-friendly" nation states. The WDC system was established during the 1957-58 International Geophysical Year at a time when the information technology infrastructure was rudimentary and central repositories of data were needed to manage and disseminate a vast quantity of environmental information. In today's internet savvy culture the need for centralized collections of data is no longer a critical element in the effective dissemination and utilization of data. The Virtual Observatory (VxO) initiative for heliophysics capitalizes on today's robust communications infrastructure to "virtually" collect and disseminate solar-geophysical data. As STP moves away from its traditional role as a central repository of environmental data it is refocusing its mission to be the authoritative provider of NOAA space weather data using dissemination tools well coupled to the VxOs. To this end and as a means to develop these tools, STP is building on revolutionary web services and user-interface technologies to create a novel and customizable interface for the presentation of original and derived data products. Overall, the focus for the division is on operational space weather data collected by NOAA's fleet of environmental satellites in polar orbit and at geosynchronous altitudes and other operational datasets acquired from the U.S. Air Force. This talk will provide both an historical overview of STP and a discussion of STP's role within the VxO initiative.

Denig, W. F.

2011-12-01

393

Leaf element concentrations of terrestrial plants across China are  

E-print Network

with leaf elements responsible for cell structure and enzymes. Main conclusions Leaf element concentrationsRESEARCH PAPER Leaf element concentrations of terrestrial plants across China are influenced cycles of terrestrial eco- systems are strongly affected by leaf element concentrations. Understanding

Slik, Ferry

394

EENY-220 Terrestrial Amphipods or “Lawn Shrimp ” (Crustacea:  

E-print Network

Amphipods comprise an order of crustacea, shrimp-like in form, which contains mostly marine and freshwater forms. While some species are terrestrial, they still require moist habitats. These terrestrial species are sometimes referred to

Amphipoda Talitridae; Thomas R. Fasulo

395

The coevolution of circumperineal color and terrestriality.  

PubMed

Old World monkeys (Cercopithecoidea) are unusual among primates for the high percentage of species exhibiting circumperineal coloration, as well as the large percentage of highly terrestrial species. Kingdon [1974, 1980] suggested that circumperineal skin coloration is functionally related to terrestriality, but this hypothesis has not been tested. From the literature, we collected data on habitat use (terrestrial/arboreal) and circumperineal coloration (present/absent) for 78 species. Indeed, among the 78 species surveyed here, 75% of them fall into either the category of colored circumperineals with terrestrial lifestyle, or of uncolored circumperineals with arboreal lifestyle (?(2) (1)?=?19.550, P?terrestrial ecology. Am. J. Primatol. 77:547-557, 2015. © 2015 Wiley Periodicals, Inc. PMID:25612177

Pampush, James D; Cramer, Jennifer D

2015-05-01

396

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

397

Terrestrial Planet Formation in Binary Star Systems  

E-print Network

A binary star system is the most common result of the star formation process, and binary companions can disrupt both the formation of terrestrial planets and their long term prospects for stability. We present results from a large set of numerical simulations of the final stages of terrestrial planet formation - from Moon- to Mars-sized planetary embryos to planets - in main-sequence binary star systems. We examine planetary accretion around both stars ('P-type' circumbinary orbits) or individual stars ('S-type' orbits) in binary systems, including terrestrial planet formation around each star in Alpha Centauri AB, the closest binary star system to the Sun. For comparison, we also simulate planetary growth from the same initial disk placed in the Sun-Jupiter-Saturn system and also around the Sun with neither giant planets nor a stellar companion perturbing the system. Our simulations show that giant and stellar companions not only truncate the disk, but hasten the accretion process by stirring up the planetary embryos to higher eccentricities and inclinations. Terrestrial planets similar to those in our Solar System formed around individual stars in simulations with the binary periastron (closest approach) greater than about 5 AU. Terrestrial planet growth within circumbinary disks was uninhibited around inner binary star systems with binary apastrons (maximum separation) less than ~0.2 AU. Results from our simulations can be scaled for different stellar and disk parameters. Approximately 50 - 60% of binary star systems - from contact binaries to separations of nearly a parsec - satisfy these constraints. Given that the galaxy contains more than 100 billion star systems, a large number of systems remain habitable based on the dynamic considerations of this research.

Elisa V. Quintana; Jack J. Lissauer

2007-05-23

398

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

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

399

The ORBCOMM data communications system  

NASA Astrophysics Data System (ADS)

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

Schoen, David C.; Locke, Paul A.

400

The ORBCOMM data communications system  

NASA Technical Reports Server (NTRS)

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

Schoen, David C.; Locke, Paul A.

1993-01-01

401

Communication architecture of an early warning system  

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

402

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

403

A satellite based algorithm for identifying dust episodes: the regime of episodes in the Mediterranean basin and evaluation against surface measurements  

NASA Astrophysics Data System (ADS)

An objective and dynamic algorithm was set up, using daily data of various aerosol optical properties from different satellite databases, which identifies the desert dust (DD) episodes and classifies them into strong and extreme ones. The algorithm is applied to derive the regime of DD episodes over the broader Mediterranean basin over the period 2000-2007. First, the algorithm was tested through comparisons against surface based particulate matter (PM) and AERONET measurements from stations distributed across the Mediterranean basin. The comparisons have shown a reasonable ability of the algorithm to detect the DD episodes occurring within the study region, with largest disagreements with PM data in summer, when African dust transport has a great vertical extent restricting the ability of PM measurements to capture them. The DD episodes in the Mediterranean basin are quite frequent (up to 11.4 episodes/year) having a significant spatial and temporal variability in their frequency of occurrence and intensity. Thus, strong DD episodes occur more frequently in the western Mediterranean basin while extreme ones appear more frequently over the central Mediterranean Sea. In addition, there is a predominant latitudinal variability in both frequency and intensity of DD episodes, both being decreased from south to north. A significant seasonal variation of the frequency of DD episodes was also found. More specifically, both strong and extreme episodes are more frequent during summer in the western Mediterranean basin and during spring in its central and eastern parts. In more than 85% of cases, Mediterranean episodes last a bit more than one day on average, but their duration can be as long as 6 days for strong episodes and 4 days for extreme ones. A noticeable year by year variability of DD episodes has been also found, especially concerning their frequency. The spatial and temporal patterns of Mediterranean DD episodes can be explained by the regional surface pressure and precipitation spatio-temporal patterns, as well as by the variability of North Atlantic Oscillation (NAO). Thus, our results indicate a decreasing frequency of Mediterranean DD episodes over the period 2000-2007, especially over land surfaces, in line with decreasing NAO Index over the same period. The present satellite based tool for identifying DD episodes is useful because it enables a complete spatial coverage, which is necessary for better understanding the larger scale processes that determine the regime of DD episodes in the Mediterranean, and it is planned to be used to other key dust regions of the globe.

Gkikas, Antonis; Hatzianastassiou, Nikos; Mihalopoulos, Nikos; Katsoulis, Vasilis; Kazadzis, Stelios; Pey, Jorge; Querol, Xavier; Torres, Omar

2013-04-01

404

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

405

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

406

Project Universe - Local area networks and satellite communications  

NASA Astrophysics Data System (ADS)

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

Ackroyd, B. R.

1983-07-01

407

The Behaviour ofIodine in the Terrestrial Environment.  

E-print Network

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

408

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

E-print Network

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

Winckler, Gisela

409

Carbon Metabolism of the Terrestrial Biosphere: A Multitechnique Approach  

E-print Network

and validate terrestrial biospheric models. An iteration and reit- eration of top-down and bottom-up approaches: 10.1007/s100210000014 ECOSYSTEMS 2000 Springer-Verlag 115 #12;INTRODUCTION The world's terrestrialCOMMENTARY Carbon Metabolism of the Terrestrial Biosphere: A Multitechnique Approach for Improved

Ehleringer, Jim

410

Tuesday, March 14, 2006 TERRESTRIAL PLANET FORMATION AND DIFFERENTIATION  

E-print Network

Tuesday, March 14, 2006 TERRESTRIAL PLANET FORMATION AND DIFFERENTIATION 1:30 p.m. Marina Plaza, and water condenses at terrestrial planet formation region. Then, planetesimals mainly composed of ice. 2:00 p.m. O'Brien D. P. * Morbidelli A. Levison H. F. Simulations of Terrestrial Planet Formation

Rathbun, Julie A.

411

Interferometer Architecture Trade Studies for the Terrestrial Planet Finder Mission  

E-print Network

Interferometer Architecture Trade Studies for the Terrestrial Planet Finder Mission by Brian J #12;2 #12;Interferometer Architecture Trade Studies for the Terrestrial Planet Finder Mission by Brian and then used to conduct trade studies for NASA's Terrestrial Planet Finder (TPF) Mission. A software tool

412

Parameters that control lithosphericscale thermal localization on terrestrial planets  

E-print Network

on terrestrial planets Fabio Crameri1 and Boris J. P. Kaus1 Received 16 February 2010; revised 31 March 2010 lengthscale. An application of the 1D model to the terrestrial planets shows that this type), Parameters that control lithosphericscale thermal localization on terrestrial planets, Geophys. Res. Lett

Kaus, Boris

413

Atmospheric Circulation of Terrestrial Exoplanets Adam P. Showman  

E-print Network

extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined). Despite a major emphasis to date on extrasolar giant planets (EGPs), super Earths and terrestrial planets

414

Terrestrial forest management plan for Palmyra Atoll  

USGS Publications Warehouse

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

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

2011-01-01

415

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

416

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

417

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

418

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

419

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

420

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

421

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

422

The optical communication link outage probability in satellite formation flying  

NASA Astrophysics Data System (ADS)

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

Arnon, Shlomi; Gill, Eberhard

2014-02-01

423

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

424

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

425

Changes in ecologically critical terrestrial climate conditions.  

PubMed

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

Diffenbaugh, Noah S; Field, Christopher B

2013-08-01

426

The debris disk - terrestrial planet connection  

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

427

The search for extra-terrestrial intelligence.  

PubMed

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

Drake, Frank

2011-02-13

428

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

429

Experimental Tribulus terrestris poisoning in goats  

Microsoft Academic Search

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

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

2004-01-01

430

Intermediate concentration systems for terrestrial photovoltaic panels  

Microsoft Academic Search

Experiments using a patented process of intermediate concentration (2 to 10x-sun) on off-the-shelf terrestrial photovoltaic panels are described. This intermediate concentration is obtained with segmented parabola collectors. The collectors are cut out of expanded polystyrene, using a hot wire and surfaced with inexpensive back surfaced mirrors. Collector widths can be varied, up to 4.88 m (16 ft) or more, to

C. B. Cluff; R. L. Call

1980-01-01

431

Terrestrial contamination in Apollo lunar samples.  

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

432

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.

433

Tectonic History of the Terrestrial Planets  

NASA Technical Reports Server (NTRS)

The topics covered include the following: patterns of deformation and volcanic flows associated with lithospheric loading by large volcanoes on Venus; aspects of modeling the tectonics of large volcanoes on the terrestrial planets; state of stress, faulting, and eruption characteristics of large volcanoes on Mars; origin and thermal evolution of Mars; geoid-to-topography ratios on Venus; a tectonic resurfacing model for Venus; the resurfacing controversy for Venus; and the deformation belts of Lavinia Planitia.

Solomon, Sean C.

1993-01-01

434

Terrestrial gamma ray flashes and lightning discharges  

Microsoft Academic Search

Analysis of ELF\\/VLF broadband data from Palmer Station, Antarctica indicates that 76% Terrestrial Gamma-ray Flashes (TGFs) detected on the RHESSI spacecraft occur in association with lightning-generated radio atmospherics arriving from near the footprint of RHESSI and within a few ms of the TGF. The remaining TGFs are not associated with any radio atmospheric, thus by implication CG lightning. The peak

M. B. Cohen; R. K. Said; D. M. Smith; L. I. Lopez

2006-01-01

435

Messaging to Extra-Terrestrial Intelligence  

E-print Network

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

Alexander Zaitsev

2006-10-05

436

Predicting Gross Primary Productivity in Terrestrial Ecosystems  

Microsoft Academic Search

Our goal was to construct a simple, highly aggregated model, driven by easily available data sets, that accurately predicted terrestrial gross primary productivity (GPP; carboxylation plus oxygenation) in diverse environments and ecosystems. Our start- ing point was a fine-scale, multilayer model of half-hourly canopy processes that has been parametrized for Harvard Forest, Massachusetts. Over varied growing season conditions, this fine-scale

Mathew Williams; Edward B. Rastetter; David N. Fernandes; Michael L. Goulden; Gaius R. Shaver; Loretta C. Johnson

1997-01-01

437