Science.gov

Sample records for combined ir-microwave satellite

  1. Combining satellite data for better tropical forest monitoring

    NASA Astrophysics Data System (ADS)

    Reiche, Johannes; Lucas, Richard; Mitchell, Anthea L.; Verbesselt, Jan; Hoekman, Dirk H.; Haarpaintner, Jörg; Kellndorfer, Josef M.; Rosenqvist, Ake; Lehmann, Eric A.; Woodcock, Curtis E.; Seifert, Frank Martin; Herold, Martin

    2016-02-01

    Implementation of policies to reduce forest loss challenges the Earth observation community to improve forest monitoring. An important avenue for progress is the use of new satellite missions and the combining of optical and synthetic aperture radar sensor data.

  2. CRRES: Combined release and radiation effects satellite program summary

    NASA Technical Reports Server (NTRS)

    Layman, Laura D.; Miller, George P.

    1993-01-01

    The experiments that comprise the Combined Release and Radiation Effects Satellite Program (CRRES) (Apr. 1990 - Jul. 1992) are presented. The experiments are as follows: PEGSAT; El Coqui; the Kwajalein Campaign; and experiments G1 - G14.

  3. Combined Global Navigation Satellite Systems in the Space Service Volume

    NASA Technical Reports Server (NTRS)

    Force, Dale A.; Miller, James J.

    2013-01-01

    Besides providing position, velocity, and timing (PVT) for terrestrial users, the Global Positioning System (GPS) is also being used to provide PVT information for earth orbiting satellites. In 2006, F. H. Bauer, et. al., defined the Space Service Volume in the paper GPS in the Space Service Volume , presented at ION s 19th international Technical Meeting of the Satellite Division, and looked at GPS coverage for orbiting satellites. With GLONASS already operational, and the first satellites of the Galileo and Beidou/COMPASS constellations already in orbit, it is time to look at the use of the new Global Navigation Satellite Systems (GNSS) coming into service to provide PVT information for earth orbiting satellites. This presentation extends GPS in the Space Service Volume by examining the coverage capability of combinations of the new constellations with GPS GPS was first explored as a system for refining the position, velocity, and timing of other spacecraft equipped with GPS receivers in the early eighties. Because of this, a new GPS utility developed beyond the original purpose of providing position, velocity, and timing services for land, maritime, and aerial applications. GPS signals are now received and processed by spacecraft both above and below the GPS constellation, including signals that spill over the limb of the earth. Support of GPS space applications is now part of the system plan for GPS, and support of the Space Service Volume by other GNSS providers has been proposed to the UN International Committee on GNSS (ICG). GPS has been demonstrated to provide decimeter level position accuracy in real-time for satellites in low Earth orbit (centimeter level in non-real-time applications). GPS has been proven useful for satellites in geosynchronous orbit, and also for satellites in highly elliptical orbits. Depending on how many satellites are in view, one can keep time locked to the GNSS standard, and through that to Universal Time as long as at least one

  4. Satellite co-locations for combined GNSS and SLR analyses

    NASA Astrophysics Data System (ADS)

    Thaller, Daniela; Dach, Rolf; Seitz, Manuela; Jäggi, Adrian; Beutler, Gerhard; Mareyen, Maria; Richter, Bernd

    2010-05-01

    The combination of Global Navigation Satellite System (GNSS) and Satellite Laser Ranging (SLR) data is done commonly by using the connection at co-located GNSS-SLR sites (station coordinates together with local ties) and by common Earth rotation parameters (ERP). Co-location of GNSS and SLR on ground is in general taken into account, co-location at the satellites is, however, generally ignored. Using satellite co-location implies that one common set of orbit parameters is estimated based on GNSS microwave and SLR observations together (apart from other common parameters, e.g., ERP, geocenter coordinates). Thus, satellite co-locations provide a very strong link between both techniques. When speaking of satellite co-locations for combining GNSS and SLR, there are in principle two different types of co-locations, namely, the one due to GNSS satellites equipped with laser retroreflector arrays (LRA) and the one due to Low Earth Orbiting (LEO) satellites equipped with GNSS antennas and an LRA. We will show that satellite co-locations are not only an additional connection to that provided by the ground stations, but that they offer even an adequate alternative to ground-based co-locations. Such an alternative is of special interest because the problems related to the local ties and their discrepancies with the coordinate differences at co-located sites are well known although the reasons are still not fully understood. Furthermore, the estimation of common orbit parameters allows it to transfer the scale directly from SLR to GNSS. Due to uncertainties in the phase center modeling for the GNSS antennas, GNSS alone cannot provide the absolute scale information, and it is often assumed that the necessity to estimate range biases may reduce the potential of SLR to deliver the scale. However, we intend to demonstrate that the SLR-derived scale does not suffer from estimating range biases. Therefore, a combined GNSS-SLR analysis using satellite co-locations at GNSS satellites

  5. Solar Power Satellite (SPS) solid-state antenna power combiner

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A low loss power-combining microstrip antenna suitable for solid state solar power satellite (SPS) application was developed. A unique approach for performing both the combining and radiating function in a single cavity-type circuit was verified, representing substantial refinements over previous demonstration models in terms of detailed geometry to obtain good matching and adequate bandwidth at the design frequency. The combiner circuit was designed, built, and tested and the overall results support the view that the solid state power-combining antenna approach is a viable candidate for a solid state SPS antenna building block.

  6. Volcanic ash cloud forecasting: combining satellite observations and dispersion modelling

    NASA Astrophysics Data System (ADS)

    Wilkins, Kate; Watson, Matthew; Webster, Helen; Thomson, David; Dacre, Helen; Mackie, Shona; Harvey, Natalie

    2014-05-01

    During the eruption of Eyjafjallajökull in April and May 2010, the London Volcanic Ash Advisory Centre demonstrated the importance of InfraRed satellite imagery for monitoring volcanic ash in the atmosphere and in validating NAME, the UK Met Office operational model used to forecast ash dispersion and to advise Civil Aviation. Significant effort has gone into researching inversion modelling using NAME and satellite retrievals of volcanic ash to infer an optimal model source term, elements of which are often unknown or highly uncertain. This presentation poses a possible alternative method for combining the two by assimilating satellite observations of downwind ash clouds into the model to create effective, virtual sources in order to constrain some of the uncertainty in the source term.

  7. The combined satellite gravity field model GOCO05s

    NASA Astrophysics Data System (ADS)

    Mayer-Guerr, Torsten

    2015-04-01

    The main objective of the GOCO ("Gravity Observation Combination") project is to compute high-accuracy and high-resolution static global gravity field models based on data of the dedicated satellite gravity missions CHAMP, GRACE, and GOCE, SLR data and kinematic orbits from different Low Earth Orbiters. For the computation of the new model GOCO05s more than 800,000,000 observations from 15 satellites are used to estimate about 122,000 gravity field parameters. GOCO05s consists not only of a static field up to degree and order 200, but the temporal variations of the gravity field are modeled as well. These are represented as regularized trend and annual signal. The main focus in the GOCO combination process is on the proper handling of the stochastic behavior of the data. Therefore, the resulting accuracy information in terms of a full variance covariance matrix is quite realistic and also published with the solution.

  8. Using GPS and satellite altimetry for combined Global Ionosphere Maps

    NASA Astrophysics Data System (ADS)

    Todorova, S.; Hobiger, T.; Schuh, H.

    The ionosphere is a dispersive medium for the observables of all space geodetic techniques operating in the microwave band such as the Global Positioning System GPS and satellite altimetry missions When the signals pass trough the ionosphere both their group and phase velocity are disturbed The effect is in first approximation proportional to the Slant Total Electron Content STEC along the ray path Thus observations carried out on two distinct frequencies can be used to obtain information about the TEC values This study aims at the development of precise Global Ionosphere Maps GIMs by combination of various space geodetic techniques As a basis for the combined model global ionosphere maps from GPS data in two hours intervals have been created The inhomogeneous distribution of the GPS stations can be partly compensated by adding satellite altimetry data The combination is done by applying a least-squares adjustment Gauss-Markov model on each set of observations and then combining the normal equations by adding the relevant matrices The integrated ionosphere model is expected to be more accurate and reliable than the results derived by the two individual methods Some first tests of the combination of GPS GIMs with altimetry data will be shown

  9. Satellite tracking by combined optimal estimation and control techniques.

    NASA Technical Reports Server (NTRS)

    Dressler, R. M.; Tabak, D.

    1971-01-01

    Combined optimal estimation and control techniques are applied for the first time to satellite tracking systems. Both radio antenna and optical tracking systems of NASA are considered. The optimal estimation is accomplished using an extended Kalman filter resulting in an estimated state of the satellite and of the tracking system. This estimated state constitutes an input to the optimal controller. The optimal controller treats a linearized system with a quadratic performance index. The maximum principle is applied and a steady-state approximation to the resulting Riccati equation is obtained. A computer program, RATS, implementing this algorithm is described. A feasibility study of real-time implementation, tracking simulations, and parameter sensitivity studies are also reported.

  10. FEC combined burst-modem for business satellite communications use

    NASA Astrophysics Data System (ADS)

    Murakami, K.; Miyake, M.; Fuji, T.; Moritani, Y.; Fujino, T.

    The authors recently developed two types of FEC (forward error correction) combined modems both applicable to low-data-rate and intermediate-data-rate TDMA international satellite communications. Each FEC combined modem consists of a QPSK (quadrature phase-shift keyed) modem, a convolutional encoder, and a Viterbi decoder. Both modems are designed taking into consideration the fast acquisition of the carrier and bit timing and the low cycle slipping rate in the low-carrier-to-noise-ratio environment. Attention is paid to designing the Viterbi decoder to be operated in a situation in which successive bursts may have different coding rates according to the punctured coding scheme. The overall scheme of the FEC combined modems are presented, and some of the key technologies applied in developing them are outlined. The hardware implementation and experimentation are also discussed. The measured data are compared with results of theoretical analysis, and relatively good performances are obtained.

  11. A web-based tool that combines satellite and weather station observations to support irrigation scheduling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract: The Satellite Irrigation Management Support (SIMS) project combines NASA's Terrestrial Observation and Prediction System (TOPS), Landsat and MODIS satellite imagery, and reference evapotranspiration from surface weather station networks to map daily crop irrigation demand in California in ...

  12. Combined processing of observations from different Global Navigation Satellite Systems

    NASA Astrophysics Data System (ADS)

    Springer, T.; Dow, J.; Sanchez, J. F.; Romero, I.

    2007-12-01

    The upcoming the Galileo GNSS and the modernisation of the GPS and Glonass systems offers many exciting opportunities and challenges in the field of geosciences in the next decade. However, in order to obtain any positive effects on our geodetic and geophysical estimates the different GNSS systems will have to be observed by multi system receivers that track all systems on all available frequencies. Furthermore, these receivers should not introduce any biases between the tracked GNSS observations. In addition to this we need analysis software that can efficiently handle these multi-system and multi-frequency observations in one single estimation process. Over the last two years ESOC has put a significant effort into its Napeos processing software. This software is now capable of combined processing of SLR, DORIS, GPS, GLONASS, and GIOVE-A data. It is routinely used for a large number of tasks within ESOC, e.g., Envisat POD, GIOVE-A orbit predictions for SLR, and for the ESOC contributions to the Galileo Geodetic Service Provider. Furthermore, it will soon officially be used for generating all the ESOC products for the International GNSS Service (IGS). In our presentation we will show results from our combined GNSS analysis, both the combination of GPS and GLONASS as well as the combination of GPS and GIOVE-A. We will focus on the challenges and we were, and in part still are, faced with when combining the data of different GNSS. We will demonstrate that at present both GLONASS and GIOVE-A do not offer any benefits for our estimates. We will conclude our contribution with a discussion on the requirements which need to be fulfilled to be able to really benefit from a combined processing of multi Global Navigation Satellite Systems.

  13. Combined satellite systems for continuous global coverage in equatorial and polar circular orbits

    NASA Astrophysics Data System (ADS)

    Ulybyshev, S. Yu.

    2015-07-01

    A method is presented to design nonuniform satellite systems for global coverage using a combination of the equatorial and polar satellite groupings. Equations are derived for determining the basic design parameters of the entire satellite system and the conditions of its closure at the joint of the polar and equatorial segments. We analyze the constitutive features of such systems and their advantages and disadvantages in comparison with the most famous types of the polar phased and kinematically correct satellite systems. We consider versions of the nonuniform satellite systems with different flight altitude and the number of spacecraft in the equatorial and polar planes, as well as we present numerical examples.

  14. Satellites

    SciTech Connect

    Burns, J.A.; Matthews, M.S.

    1986-01-01

    The present work is based on a conference: Natural Satellites, Colloquium 77 of the IAU, held at Cornell University from July 5 to 9, 1983. Attention is given to the background and origins of satellites, protosatellite swarms, the tectonics of icy satellites, the physical characteristics of satellite surfaces, and the interactions of planetary magnetospheres with icy satellite surfaces. Other topics include the surface composition of natural satellites, the cratering of planetary satellites, the moon, Io, and Europa. Consideration is also given to Ganymede and Callisto, the satellites of Saturn, small satellites, satellites of Uranus and Neptune, and the Pluto-Charon system.

  15. Combined Release and Radiation Effects Satellite (CRRES) experiments data collection, analysis, and publication

    NASA Technical Reports Server (NTRS)

    Long, Terry N.; Alzmann, Melanie O.

    1992-01-01

    The Combined Release and Radiation Effects Satellite (CRRES) program experiments data collection, analysis, and publication activities are described. These activities were associated with both the satellite chemical release and a planned Puerto Rico sounding rocket campaign. To coordinate these activities, a working group meeting was organized and conducted.

  16. Combining satellite imagery and machine learning to predict poverty.

    PubMed

    Jean, Neal; Burke, Marshall; Xie, Michael; Davis, W Matthew; Lobell, David B; Ermon, Stefano

    2016-08-19

    Reliable data on economic livelihoods remain scarce in the developing world, hampering efforts to study these outcomes and to design policies that improve them. Here we demonstrate an accurate, inexpensive, and scalable method for estimating consumption expenditure and asset wealth from high-resolution satellite imagery. Using survey and satellite data from five African countries--Nigeria, Tanzania, Uganda, Malawi, and Rwanda--we show how a convolutional neural network can be trained to identify image features that can explain up to 75% of the variation in local-level economic outcomes. Our method, which requires only publicly available data, could transform efforts to track and target poverty in developing countries. It also demonstrates how powerful machine learning techniques can be applied in a setting with limited training data, suggesting broad potential application across many scientific domains. PMID:27540167

  17. Combined Satellite - and ULS-Derived Sea-Ice Flux in the Weddell Sea

    NASA Technical Reports Server (NTRS)

    Drinkwater, M.; Liu, X.; Harms, S.

    2000-01-01

    Several years of daily microwave satellite ice-drift are combined with moored Upward Looking Sonar (ULS) ice-drafts into an ice volume flux record at points along a flux gate across the Weddell Sea, Antarctica.

  18. Combined Global Navigation Satellite Systems in the Space Service Volume

    NASA Technical Reports Server (NTRS)

    Force, Dale A.; Miller, James J.

    2015-01-01

    Besides providing position, navigation, and timing (PNT) services to traditional terrestrial and airborne users, GPS is also being increasingly used as a tool to enable precision orbit determination, precise time synchronization, real-time spacecraft navigation, and three-axis attitude control of Earth orbiting satellites. With additional Global Navigation Satellite System (GNSS) constellations being replenished and coming into service (GLONASS, Beidou, and Galileo), it will become possible to benefit from greater signal availability and robustness by using evolving multi-constellation receivers. The paper, "GPS in the Space Service Volume," presented at the ION GNSS 19th International Technical Meeting in 2006 (Ref. 1), defined the Space Service Volume, and analyzed the performance of GPS out to seventy thousand kilometers. This paper will report a similar analysis of the signal coverage of GPS in the space domain; however, the analyses will also consider signal coverage from each of the additional GNSS constellations noted earlier to specifically demonstrate the expected benefits to be derived from using GPS in conjunction with other foreign systems. The Space Service Volume is formally defined as the volume of space between three thousand kilometers altitude and geosynchronous altitude circa 36,000 km, as compared with the Terrestrial Service Volume between 3,000 km and the surface of the Earth. In the Terrestrial Service Volume, GNSS performance is the same as on or near the Earth's surface due to satellite vehicle availability and geometry similarities. The core GPS system has thereby established signal requirements for the Space Service Volume as part of technical Capability Development Documentation (CDD) that specifies system performance. Besides the technical discussion, we also present diplomatic efforts to extend the GPS Space Service Volume concept to other PNT service providers in an effort to assure that all space users will benefit from the enhanced

  19. Combined adjustment of multi-resolution satellite imagery for improved geo-positioning accuracy

    NASA Astrophysics Data System (ADS)

    Tang, Shengjun; Wu, Bo; Zhu, Qing

    2016-04-01

    Due to the widespread availability of satellite imagery nowadays, it is common for regions to be covered by satellite imagery from multiple sources with multiple resolutions. This paper presents a combined adjustment approach to integrate multi-source multi-resolution satellite imagery for improved geo-positioning accuracy without the use of ground control points (GCPs). Instead of using all the rational polynomial coefficients (RPCs) of images for processing, only those dominating the geo-positioning accuracy are used in the combined adjustment. They, together with tie points identified in the images, are used as observations in the adjustment model. Proper weights are determined for each observation, and ridge parameters are determined for better convergence of the adjustment solution. The outputs from the combined adjustment are the improved dominating RPCs of images, from which improved geo-positioning accuracy can be obtained. Experiments using ZY-3, SPOT-7 and Pleiades-1 imagery in Hong Kong, and Cartosat-1 and Worldview-1 imagery in Catalonia, Spain demonstrate that the proposed method is able to effectively improve the geo-positioning accuracy of satellite images. The combined adjustment approach offers an alternative method to improve geo-positioning accuracy of satellite images. The approach enables the integration of multi-source and multi-resolution satellite imagery for generating more precise and consistent 3D spatial information, which permits the comparative and synergistic use of multi-resolution satellite images from multiple sources.

  20. CRRES combined radiation and release effects satellite program

    NASA Technical Reports Server (NTRS)

    Giles, B. L. (Compiler); Mccook, M. A. (Compiler); Mccook, M. W. (Compiler); Miller, G. P. (Compiler)

    1995-01-01

    The various regions of the magnetosphere-ionosphere system are coupled by flows of charged particle beams and electromagnetic waves. This coupling gives rise to processes that affect both technical and non-technical aspects of life on Earth. The CRRES Program sponsored experiments which were designed to produce controlled and known input to the space environment and the effects were measured with arrays of diagnostic instruments. Large amounts of material were used to modify and perturb the environment in a controlled manner, and response to this was studied. The CRRES and PEGSAT satellites were dual-mission spacecraft with a NASA mission to perform active chemical-release experiments, grouped into categories of tracer, modification, and simulation experiments. Two sounding rocket chemical release campaigns completed the study.

  1. Identification method of satellite local components based on combined feature metrics

    NASA Astrophysics Data System (ADS)

    Zhi, Xi-yang; Hou, Qing-yu; Zhang, Wei; Sun, Xuan

    2014-11-01

    In order to meet the requirements of identification of satellite local targets, a new method based on combined feature metrics is proposed. Firstly, the geometric features of satellite local targets including body, solar panel and antenna are analyzed respectively, and then the cluster of each component are constructed based on the combined feature metrics of mathematical morphology. Then the corresponding fractal clustering criterions are given. A cluster model is established, which determines the component classification according to weighted combination of the fractal geometric features. On this basis, the identified targets in the satellite image can be recognized by computing the matching probabilities between the identified targets and the clustered ones, which are weighted combinations of the component fractal feature metrics defined in the model. Moreover, the weights are iteratively selected through particle swarm optimization to promote recognition accuracy. Finally, the performance of the identification algorithm is analyzed and verified. Experimental results indicate that the algorithm is able to identify the satellite body, solar panel and antenna accurately with identification probability up to 95%, and has high computing efficiency. The proposed method can be applied to identify on-orbit satellite local targets and possesses potential application prospects on spatial target detection and identification.

  2. Combining Satellite and in Situ Data with Models to Support Climate Data Records in Ocean Biology

    NASA Technical Reports Server (NTRS)

    Gregg, Watson

    2011-01-01

    The satellite ocean color data record spans multiple decades and, like most long-term satellite observations of the Earth, comes from many sensors. Unfortunately, global and regional chlorophyll estimates from the overlapping missions show substantial biases, limiting their use in combination to construct consistent data records. SeaWiFS and MODIS-Aqua differed by 13% globally in overlapping time segments, 2003-2007. For perspective, the maximum change in annual means over the entire Sea WiFS mission era was about 3%, and this included an El NinoLa Nina transition. These discrepancies lead to different estimates of trends depending upon whether one uses SeaWiFS alone for the 1998-2007 (no significant change), or whether MODIS is substituted for the 2003-2007 period (18% decline, P less than 0.05). Understanding the effects of climate change on the global oceans is difficult if different satellite data sets cannot be brought into conformity. The differences arise from two causes: 1) different sensors see chlorophyll differently, and 2) different sensors see different chlorophyll. In the first case, differences in sensor band locations, bandwidths, sensitivity, and time of observation lead to different estimates of chlorophyll even from the same location and day. In the second, differences in orbit and sensitivities to aerosols lead to sampling differences. A new approach to ocean color using in situ data from the public archives forces different satellite data to agree to within interannual variability. The global difference between Sea WiFS and MODIS is 0.6% for 2003-2007 using this approach. It also produces a trend using the combination of SeaWiFS and MODIS that agrees with SeaWiFS alone for 1998-2007. This is a major step to reducing errors produced by the first cause, sensor-related discrepancies. For differences that arise from sampling, data assimilation is applied. The underlying geographically complete fields derived from a free-running model is unaffected

  3. Combined Release and Radiation Effects Satellite (CRRES) Experiment: Educational planning and coordination

    NASA Technical Reports Server (NTRS)

    Vaughan, William W.; Alzmann, Melanie

    1991-01-01

    The efforts conducted to provide educational planning and development support for the Combined Release and Radiation Satellite (CRRES) Experiment are summarized. Activities regarding the scientific working group and workshop development are presented including the preparation of descriptive information on the CRRES Project.

  4. Storm diagnostic/predictive images derived from a combination of lightning and satellite imagery

    NASA Technical Reports Server (NTRS)

    Goodman, Steven J.; Buechler, Dennis E.; Meyer, Paul J.

    1988-01-01

    A technique is presented for generating trend or convective tendency images using a combination of GOES satellite imagery and cloud-to-ground lightning observations. The convective tendency images can be used for short term forecasting of storm development. A conceptual model of cloud electrical development and an example of the methodology used to generate lightning/satellite convective tendency imagery are given. Successive convective tendency images can be looped or animated to show the previous growth or decay of thunderstorms and their associated lighting activity. It is suggested that the convective tendency image may also be used to indicate potential microburst producing storms.

  5. Radiation-induced insulator discharge pulses in the CRRES Internal Discharge Monitor satellite experiment. [Combined Release and Radiation Effects Satellite

    NASA Technical Reports Server (NTRS)

    Frederickson, A. R.; Mullen, E. G.; Brautigam, D. H.; Kerns, K. J.; Robinson, P. A., Jr.; Holman, E. G.

    1991-01-01

    The Internal Discharge Monitor (IDM) is designed to observe electrical pulses from common electrical insulators in space service. The IDM is flying on the Combined Release and Radiation Effects Satellite (CRRES). The sixteen insulator samples include G10 circuit boards, FR4 and PTFE fiberglass circuit boards, FEP Teflon, alumina, and wires with common insulations. The samples are fully enclosed, mutually isolated, and space radiation penetrates 0.02 cm of aluminum before striking the samples. The IDM results indicate the rate at which insulator pulses occur. Pulsing began on the seventh orbit. The maximum pulse rate occurred near orbit 600 when over 50 pulses occurred. The average pulse rate is approximately two per orbit, but nearly half of the first 600 orbits experienced no pulses. The pulse rate per unit flux of high energy electrons has not changed dramatically over the first ten months in space. These pulse rates are in agreement with laboratory experience on shorter time scales. Several of the samples have never pulsed. IDM pulses are the seeds of larger satellite electrical anomalies. The pulse rates are compared with space radiation intensities, L shell location, and spectral distributions from the radiation spectrometers on CRRES.

  6. The Combined Release and Radiation Effects Satellite (CRRES) program: A unique series of scientific experiments

    NASA Technical Reports Server (NTRS)

    Reasoner, David L.; Mccook, Morgan W. (Editor); Vaughan, William W. (Editor)

    1990-01-01

    The Defense Department and NASA have joined in a program to study the space environment which surrounds the earth and the effects of space radiation on modern satellite electronic systems. The Combined Release and Radiation Effects Satellite (CRRES) will carry an array of active experiments including chemical releases and a complement of sophisticated scientific instruments to accomplish these objectives. Other chemical release active experiments will be performed with sub-orbital rocket probes. The chemical releases will 'paint' the magnetic and electric fields of earthspace with clouds of glowing ions. Earthspace will be a laboratory, and the releases will be studied with an extensive network of ground-, aircraft-, and satellite-based diagnostic instruments. Some of the topics discussed include the following: the effects of earthspace; the need for active experiments; types of chemical releases; the CRRES program schedule; international support and coordinated studies; photographing chemical releases; information on locating chemical releases for observation by the amateur; and CRRES as a program.

  7. De-correlated combination of two low-low Satellite-to-Satellite tracking pairs according to temporal aliasing

    NASA Astrophysics Data System (ADS)

    Murböck, Michael; Pail, Roland

    2014-05-01

    The monitoring of the temporal changes in the Earth's gravity field is of great scientific and societal importance. Within several days a homogeneous global coverage of gravity observations can be obtained with satellite missions. Temporal aliasing of background model errors into global gravity field models will be one of the largest restrictions in future satellite temporal gravity recovery. The largest errors are due to high-frequent tidal and non-tidal atmospheric and oceanic mass variations. Having a double pair low-low Satellite-to-Satellite tracking (SST) scenario on different inclined orbits reduces temporal aliasing errors significantly. In general temporal aliasing effects for a single (-pair) mission strongly depend on the basic orbital rates (Murböck et al. 2013). These are the rates of the argument of the latitude and of the longitude of the ascending node. This means that the revolution time and the length of one nodal day determine how large the temporal aliasing error effects are for each SH order. The combination of two low-low SST missions based on normal equations requires an adequate weighting of the two components. This weighting shall ensure the full de-correlation of each of the two parts. Therefore it is necessary to take the temporal aliasing errors into account. In this study it is analyzed how this can be done based on the resonance orders of the two orbits. Different levels of approximation are applied to the de-correlation approach. The results of several numerical closed-loop simulations are shown including stochastic modeling of realistic future instrument noise. It is shown that this de-correlation approach is important for maximizing the benefit of a double-pair low-low SST mission for temporal gravity recovery. Murböck M, Pail R, Daras I and Gruber T (2013) Optimal orbits for temporal gravity recovery regarding temporal aliasing. Journal of Geodesy, Springer Berlin Heidelberg, ISSN 0949-7714, DOI 10.1007/s00190-013-0671-y

  8. Solar power satellite rectenna design study: Directional receiving elements and parallel-series combining analysis

    NASA Technical Reports Server (NTRS)

    Gutmann, R. J.; Borrego, J. M.

    1978-01-01

    Rectenna conversion efficiencies (RF to dc) approximating 85 percent were demonstrated on a small scale, clearly indicating the feasibility and potential of efficiency of microwave power to dc. The overall cost estimates of the solar power satellite indicate that the baseline rectenna subsystem will be between 25 to 40 percent of the system cost. The directional receiving elements and element extensions were studied, along with power combining evaluation and evaluation extensions.

  9. The Orbiting Standards Platform. [combined satellite signal source and field strength meter

    NASA Technical Reports Server (NTRS)

    Dougherty, H. T.; Estin, A. J.; Morgan, W. L.; Woodruff, J. J.

    1978-01-01

    The Orbiting Standards Platform (OSP) is a combination satellite signal source and field strength meter which will make possible highly accurate, truly far-field measurements of large aperture antenna gain, pattern, sidelobes, and polarization as well as system G/T and EIRP. These measurements may be used to initially characterize earth station equipment and for the subsequent monitoring of its performance. This paper describes a technical-feasibility study of the OSP.

  10. Probing the magnetosphere using chemical releases from the Combined Release and Radiation Effects Satellite

    NASA Technical Reports Server (NTRS)

    Bernhardt, P. A.

    1992-01-01

    An overview is presented of the chemical release experiments from NASA's Combined Release and Radiation Effects Satellite (CRRES) program. Preliminary results are given for the CRRES investigations of (1) stimulated electron and ion precipitation, (2) ion transport in the magnetotail, (3) critical ionization velocity, (4) field line tracing and parallel acceleration, (5) diamagnetic cavity formation and collapse, and (6) plasma instabilities. The chemical vapor properties from a thermite release mechanism are also briefly described.

  11. Atmospheric Profiling Combining the Features of GPS ro & Mls: Satellite to Satellite Occultations Near Water & Ozone Absorption Lines

    NASA Astrophysics Data System (ADS)

    Kursinski, E. R.; Ward, D.; Otarola, A. C.; McGhee, J.; Reed, H.; Erickson, D.

    2015-12-01

    Assessing climate models & their predictions requires observations that determine the state of the real climate system precisely and unambiguously, independently from models. For this purpose, we have been developing a new orbiting remote sensing system called the Active Temperature, Ozone & Moisture Microwave Spectrometer (ATOMMS) which is a cross between GPS RO and the Microwave Limb Sounder. ATOMMS actively probes water vapor, ozone & other absorption lines at cm & mm wavelengths in a satellite to satellite occultation geometry to simultaneously profile temperature, pressure, water vapor and ozone as well as other important constituents. Individual profiles of water vapor, temperature & pressure heights will extend from near the surface into the mesosphere with ~1%, 0.4K and 10 m precision respectively and still better accuracy, with 100 m vertical resolution. Ozone profiles will extend upward from the upper troposphere. Line of sight wind profiles will extend upwards from the mid-stratosphere. ATOMMS is a doubly differential absorption system which eliminates drift and both sees clouds and sees thru them, to deliver performance in clouds within a factor of 2 of the performance in clear skies. This all-weather sampling combined with insensitivity to surface emissivity avoids sampling biases that limit most existing satellite records. ATOMMS will profile slant liquid water in clouds & rain and as well as turbulence via scintillations ("twinkling of a star"). Using prototype ATOMMS instrumentation that we developed with funding from NSF, several ATOMMS ground field campaigns precisely measured water vapor, cloud amount, rainfall, turbulence and absorption line spectroscopy. ATOMMS's dynamic range was demonstrated as water vapor was derived to 1% precision in optical depths up to 17. We are developing high altitude aircraft to aircraft instrumentation to further demonstrate ATOMMS performance, refine spectroscopy & support future field campaigns. Our vision is a

  12. Combining high-resolution satellite images and altimetry to estimate the volume of small lakes

    NASA Astrophysics Data System (ADS)

    Baup, F.; Frappart, F.; Maubant, J.

    2013-12-01

    This study presents an approach to determine the volume of water in small lakes (<100 ha) by combining satellite altimetry data and high-resolution (HR) images. The lake being studied is located in the south-west of France and is only used for agricultural irrigation purposes. The altimetry satellite data are provided by RA-2 sensor on board Envisat, and the high-resolution images (<10 m) are obtained from optical (Formosat-2) and synthetic aperture radar (SAR) sensors (Terrasar-X and Radarsat-2) satellites. The altimetry data (data are obtained every 35 days) and the HR images (45) have been available since 2003 and 2010, respectively. In situ data (for the water levels and volumes) going back to 2003 have been provided by the manager of the lake. Three independent approaches are developed to estimate the lake volume and its temporal variability. The first two approaches are empirical and use synchronous ground measurements of the water volume and the satellite data. The results demonstrate that altimetry and imagery can be effectively and accurately used to monitor the temporal variations of the lake (R2altimetry = 0.97, RMSEaltimetry = 5.2%, R2imagery = 0.90, and RMSEimagery = 7.4%). The third method combines altimetry (to measure the lake level) and satellite images (of the lake surface) to estimate the volume changes of the lake and produces the best results (R2 = 0.99) of the three methods, demonstrating the potential of future Sentinel and SWOT missions to monitor small lakes and reservoirs for agricultural and irrigation applications.

  13. Analysis of BeiDou Satellite Measurements with Code Multipath and Geometry-Free Ionosphere-Free Combinations.

    PubMed

    Zhao, Qile; Wang, Guangxing; Liu, Zhizhao; Hu, Zhigang; Dai, Zhiqiang; Liu, Jingnan

    2016-01-01

    Using GNSS observable from some stations in the Asia-Pacific area, the carrier-to-noise ratio (CNR) and multipath combinations of BeiDou Navigation Satellite System (BDS), as well as their variations with time and/or elevation were investigated and compared with those of GPS and Galileo. Provided the same elevation, the CNR of B1 observables is the lowest among the three BDS frequencies, while B3 is the highest. The code multipath combinations of BDS inclined geosynchronous orbit (IGSO) and medium Earth orbit (MEO) satellites are remarkably correlated with elevation, and the systematic "V" shape trends could be eliminated through between-station-differencing or modeling correction. Daily periodicity was found in the geometry-free ionosphere-free (GFIF) combinations of both BDS geostationary Earth orbit (GEO) and IGSO satellites. The variation range of carrier phase GFIF combinations of GEO satellites is -2.0 to 2.0 cm. The periodicity of carrier phase GFIF combination could be significantly mitigated through between-station differencing. Carrier phase GFIF combinations of BDS GEO and IGSO satellites might also contain delays related to satellites. Cross-correlation suggests that the GFIF combinations' time series of some GEO satellites might vary according to their relative geometries with the sun. PMID:26805831

  14. Vertical land movements from the combined use of satellite altimetry and tide gauges

    NASA Astrophysics Data System (ADS)

    Marcos, Marta; Woppelmann, Guy

    2015-04-01

    Vertical ground displacements at tide gauge sites were estimated from the differenced time series of monthly satellite altimetry sea level anomalies minus tide gauge. We have used the time series of satellite altimetry that are routinely processed and distributed by four major data providers (three gridded and one along-track products) together with monthly tide gauge records from the datum controlled data set of the Permanent Service for Mean Sea Level (PSMSL). Differenced time series were built using three variants of altimetric time series. Each resulting record was analyzed assuming a combination of white noise and power-law noise of a priori unknown spectral index. The rate uncertainties, computed taking into account the noise content in the differenced time series, will be discussed. In particular, in the context of the departures from the white noise (expected only if both the satellite altimeter and the tide gauge were recording mostly the same sea level signals and their instrumental errors were negligible) and its amplitude. The most suitable altimetric product in terms of correlation and variance reduction at tide gauges, among those investigated, will be identified. Rates of vertical land motion computed with Global Positioning System (GPS) and rates obtained from the combination of altimetry and tide gauge records will be finally compared for those stations where both measurements are available.

  15. Analysis of BeiDou Satellite Measurements with Code Multipath and Geometry-Free Ionosphere-Free Combinations

    PubMed Central

    Zhao, Qile; Wang, Guangxing; Liu, Zhizhao; Hu, Zhigang; Dai, Zhiqiang; Liu, Jingnan

    2016-01-01

    Using GNSS observable from some stations in the Asia-Pacific area, the carrier-to-noise ratio (CNR) and multipath combinations of BeiDou Navigation Satellite System (BDS), as well as their variations with time and/or elevation were investigated and compared with those of GPS and Galileo. Provided the same elevation, the CNR of B1 observables is the lowest among the three BDS frequencies, while B3 is the highest. The code multipath combinations of BDS inclined geosynchronous orbit (IGSO) and medium Earth orbit (MEO) satellites are remarkably correlated with elevation, and the systematic “V” shape trends could be eliminated through between-station-differencing or modeling correction. Daily periodicity was found in the geometry-free ionosphere-free (GFIF) combinations of both BDS geostationary Earth orbit (GEO) and IGSO satellites. The variation range of carrier phase GFIF combinations of GEO satellites is −2.0 to 2.0 cm. The periodicity of carrier phase GFIF combination could be significantly mitigated through between-station differencing. Carrier phase GFIF combinations of BDS GEO and IGSO satellites might also contain delays related to satellites. Cross-correlation suggests that the GFIF combinations’ time series of some GEO satellites might vary according to their relative geometries with the sun. PMID:26805831

  16. Combining high-resolution satellite images and altimetry to estimate the volume of small lakes

    NASA Astrophysics Data System (ADS)

    Baup, F.; Frappart, F.; Maubant, J.

    2014-05-01

    This study presents an approach to determining the volume of water in small lakes (<100 ha) by combining satellite altimetry data and high-resolution (HR) images. In spite of the strong interest in monitoring surface water resources on a small scale using radar altimetry and satellite imagery, no information is available about the limits of the remote-sensing technologies for small lakes mainly used for irrigation purposes. The lake being studied is located in the south-west of France and is only used for agricultural irrigation purposes. The altimetry satellite data are provided by an RA-2 sensor onboard Envisat, and the high-resolution images (<10 m) are obtained from optical (Formosat-2) and synthetic aperture radar (SAR) antenna (Terrasar-X and Radarsat-2) satellites. The altimetry data (data are obtained every 35 days) and the HR images (77) have been available since 2003 and 2010, respectively. In situ data (for the water levels and volumes) going back to 2003 have been provided by the manager of the lake. Three independent approaches are developed to estimate the lake volume and its temporal variability. The first two approaches (HRBV and ABV) are empirical and use synchronous ground measurements of the water volume and the satellite data. The results demonstrate that altimetry and imagery can be effectively and accurately used to monitor the temporal variations of the lake (R2ABV = 0.98, RMSEABV = 5%, R2HRBV = 0.90, and RMSEABV = 7.4%), assuming a time-varying triangular shape for the shore slope of the lake (this form is well adapted since it implies a difference inferior to 2% between the theoretical volume of the lake and the one estimated from bathymetry). The third method (AHRBVC) combines altimetry (to measure the lake level) and satellite images (of the lake surface) to estimate the volume changes of the lake and produces the best results (R2AHRBVC = 0.98) of the three methods, demonstrating the potential of future Sentinel and SWOT missions to

  17. Retrieval of temperature and water vapor from combined satellite and ground based ultra-spectral measurements

    NASA Astrophysics Data System (ADS)

    Jian, Yongxiao

    Ultra-spectrometers with a spectral resolution better than 1 cm-1, such as AIRS on the AQUA, IASI on the Metop-A/B, and CrIS on the Suomi-NPP, have become operational during the past decade. The radiance spectra measured by these satellite-borne spectrometers provide soundings of the atmosphere with relatively high vertical resolution and high accuracy except for the lower atmosphere. Meanwhile, many ground-based ultra-spectrometers based on the Michelson Interferometer have been incorporated into the Department of Energy Atmospheric Radiation Measurement facilities and aboard NOAA research vessels. These instruments provide temperature and water vapor soundings within the planetary boundary layer continuously with very high vertical resolution. This dissertation develops a retrieval procedure which can combine the radiance measured by ground-based spectrometers and coincident observation from satellite-borne instruments to improve retrieval results throughout the lower atmosphere. To verify the feasibility and improved accuracy of the combined retrieval, 90 clear sky cases from four in-situ radiosonde measurement locations or geographical regions, were selected for this study. Each region consists of radiosonde measurements of temperature and water vapor, downwelling radiance spectra measured at approximately the balloon launch time, and upwelling radiance observation by IASI at the location and time coincident with the surface radiance and radiosonde measurements. These cases indicate, that when compared with the retrieval from upwelling radiance or downwelling radiance spectra only, there is a significant improvement of the retrieval using combined upwelling and downwelling radiance spectra is observed. At altitude below the 800 hPa pressure level, the errors using the combined retrieval are about 0.5 -- 1 K in temperature, and 20 -- 40 % for water vapor mixing ratio. These errors are approximately one-third the magnitude of errors for the sounding retrieval

  18. Combining satellite, aerial and ground measurements to assess forest carbon stocks in Democratic Republic of Congo

    NASA Astrophysics Data System (ADS)

    Beaumont, Benjamin; Bouvy, Alban; Stephenne, Nathalie; Mathoux, Pierre; Bastin, Jean-François; Baudot, Yves; Akkermans, Tom

    2015-04-01

    Monitoring tropical forest carbon stocks changes has been a rising topic in the recent years as a result of REDD+ mechanisms negotiations. Such monitoring will be mandatory for each project/country willing to benefit from these financial incentives in the future. Aerial and satellite remote sensing technologies offer cost advantages in implementing large scale forest inventories. Despite the recent progress made in the use of airborne LiDAR for carbon stocks estimation, no widely operational and cost effective method has yet been delivered for central Africa forest monitoring. Within the Maï Ndombe region of Democratic Republic of Congo, the EO4REDD project develops a method combining satellite, aerial and ground measurements. This combination is done in three steps: [1] mapping and quantifying forest cover changes using an object-based semi-automatic change detection (deforestation and forest degradation) methodology based on very high resolution satellite imagery (RapidEye), [2] developing an allometric linear model for above ground biomass measurements based on dendrometric parameters (tree crown areas and heights) extracted from airborne stereoscopic image pairs and calibrated using ground measurements of individual trees on a data set of 18 one hectare plots and [3] relating these two products to assess carbon stocks changes at a regional scale. Given the high accuracies obtained in [1] (> 80% for deforestation and 77% for forest degradation) and the suitable, but still to be improved with a larger calibrating sample, model (R² of 0.7) obtained in [2], EO4REDD products can be seen as a valid and replicable option for carbon stocks monitoring in tropical forests. Further improvements are planned to strengthen the cost effectiveness value and the REDD+ suitability in the second phase of EO4REDD. This second phase will include [A] specific model developments per forest type; [B] measurements of afforestation, reforestation and natural regeneration processes and

  19. Advanced snow cover classification by combining terrestrial photography and satellite imagery

    NASA Astrophysics Data System (ADS)

    Härer, S.; Bernhardt, M.; Schulz, K.

    2013-12-01

    Terrestrial photography combined with the recently presented Photo Rectification And ClassificaTIon SoftwarE (PRACTISE V.1.0) has proven to be a valuable source to derive temporal and spatial high-resolution snow cover maps in mountain regions. However, the integrated automatic snow classification algorithm is restricted to images on equally illuminated terrain and the areal coverage of digital photographs is strongly limited. Here, we present PRACTISE V.1.1 which automatically classifies sunny and shaded areas in the photograph separately, eliminating disturbing shadow effects in the classification. The software also calculates the Normalized-Difference Snow Index (NDSI) for a simultaneously captured satellite image. Until now, it was found to be difficult to set the NDSI threshold for snow accurately even though it is critical for a correct classification. Our new method automatically optimizes the threshold value using the camera-derived snow cover map as a cost-effective technique for in-situ ground-truthing. Eventually, the satellite image is classified. The improved software was successfully tested for photographs of a single lens reflex camera and corresponding satellite images of the Landsat series in the Zugspitze massif (Germany). The results have shown that the combination of terrestrial photography and satellite imagery extends the mapping area enormously, keeping the quality of the snow cover maps high. The enlarged areal coverage enhances the potential use of this technique for validating spatially distributed snow hydrological models, even for larger catchments. The presented approach furthermore indicates that it is largely independent of the used sensor systems as well as the investigated surface variable which allows an application in other research disciplines.

  20. Global Carbon Monoxide Products from Combined AIRS, TES and MLS Measurements on A-Train Satellites

    NASA Technical Reports Server (NTRS)

    Warner, Juying X.; Yang, R.; Wei, Z.; Carminati, F.; Tangborn, A.; Sun, Z.; Lahoz, W.; Attie, J. L.; El Amraoui, L.; Duncan, B.

    2014-01-01

    This study tests a novel methodology to add value to satellite data sets. This methodology, data fusion, is similar to data assimilation, except that the background modelbased field is replaced by a satellite data set, in this case AIRS (Atmospheric Infrared Sounder) carbon monoxide (CO) measurements. The observational information comes from CO measurements with lower spatial coverage than AIRS, namely, from TES (Tropospheric Emission Spectrometer) and MLS (Microwave Limb Sounder). We show that combining these data sets with data fusion uses the higher spectral resolution of TES to extend AIRS CO observational sensitivity to the lower troposphere, a region especially important for air quality studies. We also show that combined CO measurements from AIRS and MLS provide enhanced information in the UTLS (upper troposphere/lower stratosphere) region compared to each product individually. The combined AIRS-TES and AIRS-MLS CO products are validated against DACOM (differential absorption mid-IR diode laser spectrometer) in situ CO measurements from the INTEX-B (Intercontinental Chemical Transport Experiment: MILAGRO and Pacific phases) field campaign and in situ data from HIPPO (HIAPER Pole-to-Pole Observations) flights. The data fusion results show improved sensitivities in the lower and upper troposphere (20-30% and above 20%, respectively) as compared with AIRS-only version 5 CO retrievals, and improved daily coverage compared with TES and MLS CO data.

  1. A first experiment on local combination of EGM2008 data and GOCE grids at satellite altitude

    NASA Astrophysics Data System (ADS)

    Gatti, A.; Pavlis, N. K.; Reguzzoni, M.; Sanso, F.

    2012-12-01

    The GOCE satellite of the European Space Agency (ESA), thanks to a low orbit and a very sophisticated gradiometer, is observing the Earth gravitational field with the highest level of accuracy and resolution ever reached by any geodetic missions. Although lower than other satellites, the GOCE orbit altitude of about 250 km inevitably limits the maximum achievable resolution of the estimated gravitational field; to overcome this limitations a combination with other sources of data is then necessary. One of the most informative and accurate spherical harmonic global models of the Earth gravitational field is EGM2008. It has been developed by a least squares combination between of the ITG-GRACE03S model (with its associated error covariance matrix) and a 5'x5' grid of free-air gravity anomalies. Therefore this model seems to be suitable for a combination with the newer GOCE data. The classical approach to merge these two types of information is a direct combination of the spherical harmonic coefficients coming from the satellite-only model and EGM2008. The possible drawbacks of this approach are the following: 1. Every GOCE-only spherical harmonic global model need a certain level of regularization (e.g. to deal with polar gaps) acting on a subset of coefficients but more or less affecting the estimated field all over the world. 2. The EGM2008 error description is based on publicly available coefficient variances or, at most, on a block diagonal covariance matrix when coefficients are sorted order by order; this implies that the corresponding geographical error is latitude dependent, which is an approximation far from reality. The main goal of this work is to try to overcome these limitations by computing local grids at ground level from GOCE data and EGM2008 grids. With this approach the GOCE information used is not yet regularized to produce a global model and EGM2008 could be weighted taking into account the actual geographic distribution of the error (e.g. the

  2. Combining Satellite Microwave Radiometer and Radar Observations to Estimate Atmospheric Latent Heating Profiles

    NASA Technical Reports Server (NTRS)

    Grecu, Mircea; Olson, William S.; Shie, Chung-Lin; L'Ecuyer, Tristan S.; Tao, Wei-Kuo

    2009-01-01

    In this study, satellite passive microwave sensor observations from the TRMM Microwave Imager (TMI) are utilized to make estimates of latent + eddy sensible heating rates (Q1-QR) in regions of precipitation. The TMI heating algorithm (TRAIN) is calibrated, or "trained" using relatively accurate estimates of heating based upon spaceborne Precipitation Radar (PR) observations collocated with the TMI observations over a one-month period. The heating estimation technique is based upon a previously described Bayesian methodology, but with improvements in supporting cloud-resolving model simulations, an adjustment of precipitation echo tops to compensate for model biases, and a separate scaling of convective and stratiform heating components that leads to an approximate balance between estimated vertically-integrated condensation and surface precipitation. Estimates of Q1-QR from TMI compare favorably with the PR training estimates and show only modest sensitivity to the cloud-resolving model simulations of heating used to construct the training data. Moreover, the net condensation in the corresponding annual mean satellite latent heating profile is within a few percent of the annual mean surface precipitation rate over the tropical and subtropical oceans where the algorithm is applied. Comparisons of Q1 produced by combining TMI Q1-QR with independently derived estimates of QR show reasonable agreement with rawinsonde-based analyses of Q1 from two field campaigns, although the satellite estimates exhibit heating profile structure with sharper and more intense heating peaks than the rawinsonde estimates. 2

  3. Combining satellite data with ancillary data to produce a refined land-use/land-cover map

    USGS Publications Warehouse

    Stewart, J.S.

    1998-01-01

    As part of the U.S. Geological Survey's National Water-Quality Assessment Program in the Western Lake Michigan Drainages Study Unit, a current map of land use and land cover is needed to gain a better understanding of how land use and land cover may influence water quality. Satellite data from the Landsat Thematic Mapper provides a means to map and measure the type and amount of various land-cover types across the Study Unit and can be easily updated as changes occur in the landscape or in water quality. Translating these land cover categories to land use, however, requires the use of other thematic maps or ancillary data layers, such as wetland inventories, population data, or road networks. This report describes a process of (1) using satellite imagery to produce a land-cover map for the Fox/Wolf River basin, a portion of the Western Lake Michigan Drainages NAWQA Study Unit and (2) improving the satellite-derived land-cover map by using other thematic maps. The multiple data layers are processed in a geographic information system (GIS), and the combination provides more information than individual sources alone.

  4. Statistical Evaluation of Combined Daily Gauge Observations and Rainfall Satellite Estimations over Continental South America

    NASA Technical Reports Server (NTRS)

    Vila, Daniel; deGoncalves, Luis Gustavo; Toll, David L.; Rozante, Jose Roberto

    2008-01-01

    This paper describes a comprehensive assessment of a new high-resolution, high-quality gauge-satellite based analysis of daily precipitation over continental South America during 2004. This methodology is based on a combination of additive and multiplicative bias correction schemes in order to get the lowest bias when compared with the observed values. Inter-comparisons and cross-validations tests have been carried out for the control algorithm (TMPA real-time algorithm) and different merging schemes: additive bias correction (ADD), ratio bias correction (RAT) and TMPA research version, for different months belonging to different seasons and for different network densities. All compared merging schemes produce better results than the control algorithm, but when finer temporal (daily) and spatial scale (regional networks) gauge datasets is included in the analysis, the improvement is remarkable. The Combined Scheme (CoSch) presents consistently the best performance among the five techniques. This is also true when a degraded daily gauge network is used instead of full dataset. This technique appears a suitable tool to produce real-time, high-resolution, high-quality gauge-satellite based analyses of daily precipitation over land in regional domains.

  5. The combination of satellite observation techniques for sequential ionosphere VTEC modeling

    NASA Astrophysics Data System (ADS)

    Erdogan, Eren; Limberger, Marco; Schmidt, Michael; Seitz, Florian; Dettmering, Denise; Börger, Klaus; Brandert, Sylvia; Görres, Barbara; Kersten, Wilhelm F.; Bothmer, Volker; Hinrichs, Johannes; Venzmer, Malte; Mrotzek, Niclas

    2016-04-01

    The project OPTIMAP is a joint initiative by the Bundeswehr GeoInformation Centre (BGIC), the German Space Situational Awareness Centre (GSSAC), the German Geodetic Research Institute of the Technical University of Munich (DGFI-TUM) and the Institute for Astrophysics at the University of Göttingen (IAG). The main goal is to develop an operational tool for ionospheric mapping and prediction (OPTIMAP). A key feature of the project is the combination of different satellite observation techniques to improve the spatio-temporal data coverage and the sensitivity for selected target parameters. In the current status, information about the vertical total electron content (VTEC) is derived from the dual frequency signal processing of four techniques: (1) Terrestrial observations of GPS and GLONASS ensure the high-resolution coverage of continental regions, (2) the satellite altimetry mission Jason-2 is taken into account to provide VTEC in nadir direction along the satellite tracks over the oceans, (3) GPS radio occultations to Formosat-3/COSMIC are exploited for the retrieval of electron density profiles that are integrated to obtain VTEC and (4) Jason-2 carrier-phase observations tracked by the on-board DORIS receiver are processed to determine the relative VTEC. All measurements are sequentially pre-processed in hourly batches serving as input data of a Kalman filter (KF) for modeling the global VTEC distribution. The KF runs in a predictor-corrector mode allowing for the sequential processing of the measurements where update steps are performed with one-minute sampling in the current configuration. The spatial VTEC distribution is represented by B-spline series expansions, i.e., the corresponding B-spline series coefficients together with additional technique-dependent unknowns such as Differential Code Biases and Intersystem Biases are estimated by the KF. As a preliminary solution, the prediction model to propagate the filter state through time is defined by a random

  6. The Asian Tropopause Aerosol layer through satellite and balloon-borne measurements combined with modelling approaches.

    NASA Astrophysics Data System (ADS)

    Vernier, J. P.; Fairlie, T. D.; Natarajan, M.; Crawford, J. H.; Baker, N. C.; Wegner, T.; Deshler, T.; Gadhavi, H. S.; Kumar, S.; Singh, A. K.; Jayaraman, A.; Raj, A.; Alladi, H.; Ratnam, M. V.; Pandit, A.; Vignelles, D.; Wienhold, F.; Liu, H.; Kumar, S.

    2015-12-01

    The Asian tropopause Aerosol Layer (ATAL) is a seasonal aerosol feature occurring in the Upper Troposphere and Lower Stratosphere (UTLS) above Asia during the Summer Asian Monsoon. Vertically resolved aerosol backscatter profiles from the Cloud-Aerosol Lidar and Infrared Pathfinder satellite Observation (CALIPSO) mission and extinction profiles from the Stratospheric Aerosol and Gas Experiment (SAGE) have been used to infer the spatial and temporal distributions of the ATAL since the late 90's. We found that aerosol optical thickness between 13-18km have increased by a factor of 2-3 over the past 16 years likely related to raising pollution levels in South East Asia occuring during the same period. Modelling studies of the ATAL using WACCAM 3 and GEOS-Chem have provided conflicting information on its origin and a better representation of in-cloud SO2 and aerosol lifetime in GOES-Chem seems to be key to obtain consistent results with the few SO2 measurements available in the UTLS during the Asian Monsoon. In situ measurements of aerosol and trace gases in the UTLS from several balloon campaigns which took place in summer 2014 and 2015 in Asia will be presented and discussed with combined satellite and modelling analysis.

  7. Detecting Disaster Damage from 2015 Typhoon Etau by the Combined Use of Different SAR Satellites

    NASA Astrophysics Data System (ADS)

    Honda, Kenichi; Fujihira, Kei; Asada, Norichika; Fukushima, Ayumi; Mushiake, Naruo

    2016-06-01

    In this study, focusing on the flood damages in Joso City in Ibaraki Prefecture, we estimated the extent of inundation using multiple SAR satellites and examined their varied results depending on observational bands. We further examined the potential utilization of combined different SAR data for initial responses to disasters. For classification of the inundated areas, a binary classification was used with a threshold of backscatter coefficient and the difference in backscatter coefficient between the usual condition and the situation after the breach. In the extraction of inundation after the breach of the levee, COSMO-SkyMed showed the accuracy of 72.6%, while ALOS-2 PALSAR-2 indicated the accuracy of 66.1%. The extent of inundation were extracted by difference of backscatter coefficient using the data taken by Sentinel-1 and ALOS-2 PALSAR-2 before the breach of the levee, and the comparison analysis results showed that the extent of inundation expanded after the breach of the levee. From the above results, we graded the characteristics of the satellites by their observational bands and spatial resolution.

  8. The combined release and radiation effects satellite, a joint NASA/DOD program

    NASA Technical Reports Server (NTRS)

    Berrier, D. J.

    1986-01-01

    The Combined Release and Radiation Effects Satellite (CRRES) program is a two-phase joint USAF/NASA program consisting of a low Earth orbit (LEO) phase and a geosynchronous transfer orbit (GTO) phase. The mission has been carefully planned to help clarify the geospace environment picture and its effects on space hardware, communications, and man. CRRES instruments were selected for synergism, accuracy, and applicability, and will be cross-calibrated for consistency. They will provide data to fill the gaps in geospace modeling data already obtained, and will update and correct existing models. The chemical release experiments and low altitude instruments will clarify the character of the ionosphere in low Earth orbit and the high altitude chemical release experiments will improve knowledge of how trapped particle populations behave out as far as synchronous altitudes. The ionospheric studies will lead to significantly improved Earth-space intercommunications.

  9. Atmospheric Diabatic Heating Distributions Derived from a Combination of Satellite Sensor Data

    NASA Astrophysics Data System (ADS)

    Olson, W. S.; L'Ecuyer, T. S.; Gu, G.; Grecu, M.; Bosilovich, M. G.

    2010-12-01

    Satellite estimates of atmospheric latent+eddy heating (Q1-QR) and radiative heating (QR) are combined to yield estimates of the large-scale diabatic heating, or apparent heat source (Q1). The latent+eddy and radiative heating estimates rely on cloud and precipitation information from TRMM Microwave Imager (TMI) data, with additional cloud information supplied by the TRMM Visible and Infrared Scanner (VIRS) and clear-air environmental properties from NCEP reanalyses. Comparisons of the diabatic heating estimates to those derived primarily from the TRMM Precipitation Radar (PR) and from rawinsonde diagnostic budgets are favorable, although some biases due to differences in sampling and the limited sensitivity of the TMI are noted. The addition of an approximate Q1-QR estimate for non-precipitating regions leads to mean heating from precipitating/non-precipitating Q1-QR and mean cooling from QR in the troposphere that are roughly balanced over the TRMM domain. Recently, an eleven-year database of diabatic heating has been constructed using TRMM observations from 1998-2008, as part of NASA’s Energy and Water cycle Study (NEWS) program. Initial applications of this dataset have been the delineation of the seasonal cycle in the tropics/subtropics, the distribution of heating anomalies associated with the phases of ENSO, and the progression of heating in the Madden Julian Oscillation. Preliminary comparisons of satellite heating estimates versus model-based heating and dynamical fields from the Modern Era Retrospective-Analysis for Research and Applications (MERRA) will be presented at the conference.

  10. Tropical Rainfall Distributions Determined Using TRMM Combined with Other Satellite and Rain Gauge Information.

    NASA Astrophysics Data System (ADS)

    Adler, Robert F.; Huffman, George J.; Bolvin, David T.; Curtis, Scott; Nelkin, Eric J.

    2000-12-01

    A technique is described to use Tropical Rainfall Measuring Mission (TRMM) combined radar-radiometer information to adjust geosynchronous infrared satellite data [the TRMM Adjusted Geostationary Operational Environmental Satellite Precipitation Index (AGPI)]. The AGPI is then merged with rain gauge information (mostly over land) to provide finescale (1° latitude × 1° longitude) pentad and monthly analyses, respectively. The TRMM merged estimates are 10% higher than those from the Global Precipitation Climatology Project (GPCP) when integrated over the tropical oceans (37°N-37°S) for 1998, with 20% differences noted in the most heavily raining areas. In the dry subtropics the TRMM values are smaller than the GPCP estimates. The TRMM merged product tropical-mean estimates for 1998 are 3.3 mm day1 over ocean and 3.1 mm day1 over land and ocean combined. Regional differences are noted between the western and eastern Pacific Ocean maxima when TRMM and GPCP are compared. In the eastern Pacific rain maximum the TRMM and GPCP mean values are nearly equal, which is very different from the other tropical rainy areas where TRMM merged product estimates are higher. This regional difference may indicate that TRMM is better at taking into account the vertical structure of the rain systems and the difference in structure between the western and eastern (shallower) Pacific convection.Comparisons of these TRMM merged analysis estimates with surface datasets shows varied results; the bias is near zero when compared with western Pacific Ocean atoll rain gauge data, but is significantly positive as compared with Kwajalein radar estimates (adjusted by rain gauges). Over land the TRMM estimates also show a significant positive bias. The inclusion of gauge information in the final merged product significantly reduces the bias over land, as expected.The monthly precipitation patterns produced by the TRMM merged data process clearly show the evolution of the El Ni

  11. Fluxgate magnetometer analysis and simulation software for the Combined Release and Radiation Effects Satellite (CRRES). Technical report

    SciTech Connect

    McNeil, W.J.; Singer, H.J.

    1986-10-01

    A software package was designed to simulate the operation of the fluxgate magnetometer to be flown on the Combined Release and Radiation Effects Satellite (CRRES). Algorithms are presented to create a one-second averaged data base from a simulated data stream from a spinning satellite in a realistic earth's magnetic field. Methods are devised to perform on-orbit calibration, to despin the data and to use a model field for calibration. Expressions are presented for both the signals and errors in signals introduced by inaccurate calibration parameters. The time requirement for processing are estimated.

  12. Improving The Retrieval Of Atmospheric Stability Indices By Combining Ground-based And Satellite Remote Sensing

    NASA Astrophysics Data System (ADS)

    Loehnert, U.; Ebell, K.; Orlandi, E.

    2015-12-01

    A new generation of high-resolution (~1km) weather forecast models now becoming operational over Europe promises to revolutionize predictions of severe weather, specifically by explicitly resolving convection. For this, a dense observing network is required, focusing especially on the lowest few km of the atmosphere, so that forecast models have the most realistic state of the atmosphere for initialization, continuous assimilation and verification. In this context, the current European COST action TOPROF (ES1303) deals with operational networking of three existing but so far under-exploited, ground-based remote sensing instruments throughout Europe: i) Several hundreds of ceilometers, ii) more than 20 Doppler lidars, and iii) About 30 microwave profilers (MWP) giving profiles of temperature and humidity in the lowest few km every 10 minutes. Specifically, MWP are highly suited for continuously monitoring the temporal development of atmospheric stability (i.e. Cimini et al. 2015, AMT) before the initiation of deep convection. However, the vertical resolution of MWP temperature profiles is best in the lowest kilometer above the surface, decreasing rapidly with increasing height. In addition, humidity profile retrievals typically cannot be resolved with more than two degrees of freedom for signal, resulting in a rather poor vertical resolution throughout the troposphere. Typical stability indices (i.e. K-index, Lifted Index, Showalter Index, CAPE,..) rely on temperature and humidity values not only in the region of the boundary layer (850 hPa) but also at 700 hPa, 500 hPa, in between these levels or even higher above. In this study, for clear sky cases, satellite remote sensing (i.e. SEVIRI radiances from the geostationary METEOSAT ) is used to complement the ground-based MWP information. The theoretical basis of the combined retrieval is highlighted, error reductions resulting from the sensor synergy are discussed and applications to real data are shown. The study

  13. Tropical Rainfall Analysis Using TRMM in Combination With Other Satellite Gauge Data: Comparison with Global Precipitation Climatology Project (GPCP) Results

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Huffman, George J.; Bolvin, David; Nelkin, Eric; Curtis, Scott

    1999-01-01

    This paper describes recent results of using Tropical Rainfall Measuring Mission (TRMM) information as the key calibration tool in a merged analysis on a 1 deg x 1 deg latitude/longitude monthly scale based on multiple satellite sources and raingauge analysis. The procedure used to produce the GPCP data set is a stepwise approach which first combines the satellite low-orbit microwave and geosynchronous IR observations into a "multi-satellite" product and than merges that result with the raingauge analysis. Preliminary results produced with the still-stabilizing TRMM algorithms indicate that TRMM shows tighter spatial gradients in tropical rain maxima with higher peaks in the center of the maxima. The TRMM analyses will be used to evaluate the evolution of the 1998 ENSO variations, again in comparison with the GPCP analyses.

  14. On the spectral combination of satellite gravity model, terrestrial and airborne gravity data for local gravimetric geoid computation

    NASA Astrophysics Data System (ADS)

    Jiang, Tao; Wang, Yan Ming

    2016-07-01

    One of the challenges for geoid determination is the combination of heterogeneous gravity data. Because of the distinctive spectral content of different data sets, spectral combination is a suitable candidate for its solution. The key to have a successful combination is to determine the proper spectral weights, or the error degree variances of each data set. In this paper, the error degree variances of terrestrial and airborne gravity data at low degrees are estimated by the aid of a satellite gravity model using harmonic analysis. For higher degrees, the error covariances are estimated from local gravity data first, and then used to compute the error degree variances. The white and colored noise models are also used to estimate the error degree variances of local gravity data for comparisons. Based on the error degree variances, the spectral weights of satellite gravity models, terrestrial and airborne gravity data are determined and applied for geoid computation in Texas area. The computed gravimetric geoid models are tested against an independent, highly accurate geoid profile of the Geoid Slope Validation Survey 2011 (GSVS11). The geoid computed by combining satellite gravity model GOCO03S and terrestrial (land and DTU13 altimetric) gravity data agrees with GSVS11 to ±1.1 cm in terms of standard deviation along a line of 325 km. After incorporating the airborne gravity data collected at 11 km altitude, the standard deviation is reduced to ±0.8 cm. Numerical tests demonstrate the feasibility of spectral combination in geoid computation and the contribution of airborne gravity in an area of high quality terrestrial gravity data. Using the GSVS11 data and the spectral combination, the degree of correctness of the error spectra and the quality of satellite gravity models can also be revealed.

  15. The Combined Release and Radiation Effects Satellite program (CRRES): A unique series of scientific experiments

    NASA Technical Reports Server (NTRS)

    1991-01-01

    CRRES is a program to study the space environment which surrounds Earth and the effects of space radiation on modern satellite electronic systems. The satellite will carry an array of active experiments including chemical releases and a complement of sophisticated scientific instruments to accomplish these objectives. Other chemical release active experiments will be performed with suborbital rocket probes. These chemical releases will paint the magnetic and electric fields in Earthspace with clouds of glowing ions. Earthspace will be a laboratory, and the releases will be studied with an extensive network of ground-, aircraft-, and satellite-based diagnostic instruments.

  16. Estimation of Sea Ice Thickness Distributions through the Combination of Snow Depth and Satellite Laser Altimetry Data

    NASA Technical Reports Server (NTRS)

    Kurtz, Nathan T.; Markus, Thorsten; Cavalieri, Donald J.; Sparling, Lynn C.; Krabill, William B.; Gasiewski, Albin J.; Sonntag, John G.

    2009-01-01

    Combinations of sea ice freeboard and snow depth measurements from satellite data have the potential to provide a means to derive global sea ice thickness values. However, large differences in spatial coverage and resolution between the measurements lead to uncertainties when combining the data. High resolution airborne laser altimeter retrievals of snow-ice freeboard and passive microwave retrievals of snow depth taken in March 2006 provide insight into the spatial variability of these quantities as well as optimal methods for combining high resolution satellite altimeter measurements with low resolution snow depth data. The aircraft measurements show a relationship between freeboard and snow depth for thin ice allowing the development of a method for estimating sea ice thickness from satellite laser altimetry data at their full spatial resolution. This method is used to estimate snow and ice thicknesses for the Arctic basin through the combination of freeboard data from ICESat, snow depth data over first-year ice from AMSR-E, and snow depth over multiyear ice from climatological data. Due to the non-linear dependence of heat flux on ice thickness, the impact on heat flux calculations when maintaining the full resolution of the ICESat data for ice thickness estimates is explored for typical winter conditions. Calculations of the basin-wide mean heat flux and ice growth rate using snow and ice thickness values at the 70 m spatial resolution of ICESat are found to be approximately one-third higher than those calculated from 25 km mean ice thickness values.

  17. Tropical Rainfall Distributions Determined Using TRMM Combined with other Satellite and Raingauge Information

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Huffman, George J.; Bolvin, David T.; Curtis, Scott; Nelkin, Eric J.

    1999-01-01

    Abstract A technique is described to use Tropical Rain Measuring Mission (TRMM) combined radar/radiometer information to adjust geosynchronous infrared satellite data (the TRMM Adjusted GOES Precipitation Index, or TRMM AGPI). The AGPI is then merged with rain gauge information (mostly over land; the TRMM merged product) to provide fine- scale (1 deg latitude/longitude) pentad and monthly analyses, respectively. The TRMM merged estimates are 10% higher than those from the Global Precipitation Climatology Project (GPCP) when integrated over the tropical oceans (37 deg N-S) for 1998, with 20% differences noted in the most heavily raining areas. In the dry subtropics the TRMM values are smaller than the GPCP estimates. The TRMM merged-product tropical-mean estimates for 1998 are 3.3 mm/ day over ocean and 3.1 mm/ day over land and ocean combined. Regional differences are noted between the western and eastern Pacific Ocean maxima when TRMM and GPCP are compared. In the eastern Pacific rain maximum the TRMM and GPCP mean values are nearly equal, very different from the other tropical rainy areas where TRMM merged-product estimates are higher. This regional difference may indicate that TRMM is better at taking in to account the vertical structure of the rain systems and the difference in structure between the western and eastern (shallower) Pacific convection. Comparisons of these TRMM merged analysis estimates with surface data sets shows varied results; the bias is near zero when compared to western Pacific Ocean atoll raingauge data, but significantly positive compared to Kwajalein radar estimates (adjusted by rain gauges). Over land the TRMM estimates also show a significant positive bias. The inclusion of gauge information in the final merged product significantly reduces the bias over land, as expected. The monthly precipitation patterns produced by the TRMM merged data process clearly show the evolution of the ENSO tropical precipitation pattern from early 1998

  18. Mitigating hazards to aircraft from drifting volcanic clouds by comparing and combining IR satellite data with forward transport models

    NASA Astrophysics Data System (ADS)

    Matiella Novak, M. Alexandra

    Volcanic ash clouds in the upper atmosphere (>10km) present a significant hazard to the aviation community and in some cases cause near-disastrous situations for aircraft that inadvertently encounter them. The two most commonly used techniques for mitigating hazards to aircraft from drifting volcanic clouds are (1) using data from satellite observations and (2) the forecasting of dispersion and trajectories with numerical models. This dissertation aims to aid in the mitigation of this hazard by using Moderate Infrared Resolution Spectroradiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) infrared (IR) satellite data to quantitatively analyze and constrain the uncertainties in the PUFF volcanic ash transport model. Furthermore, this dissertation has experimented with the viability of combining IR data with the PUFF model to increase the model's reliability. Comparing IR satellite data with forward transport models provides valuable information concerning the uncertainty and sensitivity of the transport models. A study analyzing the viability of combining satellite-based information with the PUFF model was also done. Factors controlling the cloud-shape evolution, such as the horizontal dispersion coefficient, vertical distribution of particles, the height of the cloud, and the location of the cloud were all updated based on observations from satellite data in an attempt to increase the reliability of the simulations. Comparing center of mass locations--calculated from satellite data--to HYSPLIT trajectory simulations provides insight into the vertical distribution of the cloud. A case study of the May 10, 2003 Anatahan Volcano eruption was undertaken to assess methods of calculating errors in PUFF simulations with respect to the transport and dispersion of the erupted cloud. An analysis of the factors controlling the cloud-shape evolution of the cloud in the model was also completed and compared to the shape evolution of the cloud observed in the

  19. Tropical forest monitoring, combining satellite and social data, to inform management and livelihood implications: Case studies from Indonesian West Timor

    NASA Astrophysics Data System (ADS)

    Fisher, Rohan

    2012-06-01

    Deforestation in the world's tropics is an urgent international issue. One response has been the development of satellite based monitoring initiatives largely focused on the carbon rich forests of western Indonesia. In contrast this study focuses on one eastern Indonesian district, Kabupaten Kupang, which has some of the largest and least studied tracts of remaining forest in West Timor. A combination of remote sensing, GIS and social science methods were used to describe the state of forests in Kabupaten Kupang, how and why they are changing. Using satellite imagery, case studies and on-ground interviews, this study explores the proposition that transdisciplinary local social, cultural and biophysical knowledge is important for effectively using remotely sensed data as a tool to inform local management policies. When compared to some other parts of Indonesia, the rate and extent of deforestation in West Timor was found to be relatively small and a satellite based assessment alone could conclude that it is not a critical issue. However this study showed that when on-ground social data are coupled with (such) satellite-based data a more complex picture emerges, related to key livelihood issues. The causes of forest cover change were found to be multivariate and location specific, requiring management approaches tailored to local social issues. This study suggests that integrative research can maximise the utility of satellite data for understanding causation and thus informing management strategies. In addition, the satellite based assessment found that at the time of the study less than 4% of forested land was within national parks and nature reserves and less than a third of the protected catchment forest zone was forested. These data suggest considerable scope for upland re-forestation activities or the redrawing of protected forest boundaries.

  20. Numerical reconstruction of tsunami source using combined seismic, satellite and DART data

    NASA Astrophysics Data System (ADS)

    Krivorotko, Olga; Kabanikhin, Sergey; Marinin, Igor

    2014-05-01

    Recent tsunamis, for instance, in Japan (2011), in Sumatra (2004), and at the Indian coast (2004) showed that a system of producing exact and timely information about tsunamis is of a vital importance. Numerical simulation is an effective instrument for providing such information. Bottom relief characteristics and the initial perturbation data (a tsunami source) are required for the direct simulation of tsunamis. The seismic data about the source are usually obtained in a few tens of minutes after an event has occurred (the seismic waves velocity being about five hundred kilometres per minute, while the velocity of tsunami waves is less than twelve kilometres per minute). A difference in the arrival times of seismic and tsunami waves can be used when operationally refining the tsunami source parameters and modelling expected tsunami wave height on the shore. The most suitable physical models related to the tsunamis simulation are based on the shallow water equations. The problem of identification parameters of a tsunami source using additional measurements of a passing wave is called inverse tsunami problem. We investigate three different inverse problems of determining a tsunami source using three different additional data: Deep-ocean Assessment and Reporting of Tsunamis (DART) measurements, satellite wave-form images and seismic data. These problems are severely ill-posed. We apply regularization techniques to control the degree of ill-posedness such as Fourier expansion, truncated singular value decomposition, numerical regularization. The algorithm of selecting the truncated number of singular values of an inverse problem operator which is agreed with the error level in measured data is described and analyzed. In numerical experiment we used gradient methods (Landweber iteration and conjugate gradient method) for solving inverse tsunami problems. Gradient methods are based on minimizing the corresponding misfit function. To calculate the gradient of the misfit

  1. Combining satellite precipitation and long-term ground observations for hydrological monitoring in China

    NASA Astrophysics Data System (ADS)

    Zhang, Xuejun; Tang, Qiuhong

    2015-07-01

    Satellite real-time precipitation enables hydrological monitoring in China where the near-real-time ground observations are not readily available. However, the inconsistency between the real-time satellite precipitation and gauge-based retrospective data may introduce large systematic bias in near-real-time hydrological monitoring. Here we attempted to integrate the Tropical Rainfall Measuring Mission (TRMM) real-time precipitation (3B42RTV7) into a 62 year gauge-based retrospective product, the IGSNRR (Institute of Geographical Sciences and Natural Resources Research) dataset through matching their cumulative probability functions toward a near-real-time hydrological monitoring consistent with the long-term retrospective simulations. A nearly 11 year period from March 2000 to December 2010 was taken as the training period to establish the satellite-gauge precipitation relationship, which was employed in the period of 2011-2013 to evaluate the performance of the adjustment. The results show that the adjusted 3B42RTV7 matches well with IGSNRR precipitation, while the unadjusted data tend to overestimate precipitation. Forced by the adjusted 3B42RTV7, the Variable Infiltration Capacity model can reproduce the IGSNRR-derived hydrographs and high/low flows better than the model forced by the unadjusted data. The percentiles of the adjusted hydrological estimates in the 62 year estimates from IGSNRR are used for near-real-time assessment of hydrological extremes. The hydrological monitoring assisted by the adjusted satellite precipitation, which enables the employment of the long-term ground observations, is able to capture more detailed drought information than that before adjustment. Our experiment suggests that the satellite real-time precipitation, after adjustment, can generate the current hydrological conditions which can be directly compared with the long-term climatology, and thus facilitates near-real-time diagnosis and detection of hydrological extremes.

  2. Simultaneous hierarchical segmentation and vectorization of satellite images through combined data sampling and anisotropic triangulation

    SciTech Connect

    Grazzini, Jacopo; Prasad, Lakshman; Dillard, Scott

    2010-10-21

    The automatic detection, recognition , and segmentation of object classes in remote sensed images is of crucial importance for scene interpretation and understanding. However, it is a difficult task because of the high variability of satellite data. Indeed, the observed scenes usually exhibit a high degree of complexity, where complexity refers to the large variety of pictorial representations of objects with the same semantic meaning and also to the extensive amount of available det.ails. Therefore, there is still a strong demand for robust techniques for automatic information extraction and interpretation of satellite images. In parallel, there is a growing interest in techniques that can extract vector features directly from such imagery. In this paper, we investigate the problem of automatic hierarchical segmentation and vectorization of multispectral satellite images. We propose a new algorithm composed of the following steps: (i) a non-uniform sampling scheme extracting most salient pixels in the image, (ii) an anisotropic triangulation constrained by the sampled pixels taking into account both strength and directionality of local structures present in the image, (iii) a polygonal grouping scheme merging, through techniques based on perceptual information , the obtained segments to a smaller quantity of superior vectorial objects. Besides its computational efficiency, this approach provides a meaningful polygonal representation for subsequent image analysis and/or interpretation.

  3. Combined assimilation of streamflow and satellite soil moisture with the particle filter and geostatistical modeling

    NASA Astrophysics Data System (ADS)

    Yan, Hongxiang; Moradkhani, Hamid

    2016-08-01

    Assimilation of satellite soil moisture and streamflow data into a distributed hydrologic model has received increasing attention over the past few years. This study provides a detailed analysis of the joint and separate assimilation of streamflow and Advanced Scatterometer (ASCAT) surface soil moisture into a distributed Sacramento Soil Moisture Accounting (SAC-SMA) model, with the use of recently developed particle filter-Markov chain Monte Carlo (PF-MCMC) method. Performance is assessed over the Salt River Watershed in Arizona, which is one of the watersheds without anthropogenic effects in Model Parameter Estimation Experiment (MOPEX). A total of five data assimilation (DA) scenarios are designed and the effects of the locations of streamflow gauges and the ASCAT soil moisture on the predictions of soil moisture and streamflow are assessed. In addition, a geostatistical model is introduced to overcome the significantly biased satellite soil moisture and also discontinuity issue. The results indicate that: (1) solely assimilating outlet streamflow can lead to biased soil moisture estimation; (2) when the study area can only be partially covered by the satellite data, the geostatistical approach can estimate the soil moisture for those uncovered grid cells; (3) joint assimilation of streamflow and soil moisture from geostatistical modeling can further improve the surface soil moisture prediction. This study recommends that the geostatistical model is a helpful tool to aid the remote sensing technique and the hydrologic DA study.

  4. Satellite observations of tropospheric formaldehyde combining GOME-2 and OMI measurements.

    NASA Astrophysics Data System (ADS)

    De Smedt, Isabelle; Van Roozendael, Michel; Stavrakou, Trissevgeny; Müller, Jean-François; Pinardi, Gaia; Hendrick, François

    2014-05-01

    This work addresses the observation of tropospheric formaldehyde (H2CO) at the global scale using multiple nadir UV sensors, in an attempt to characterize the variability and long-term changes in NMVOC emissions, related to pollution, climate and land use changes. We present an updated version (v13) of the TEMIS formaldehyde data products retrieved from GOME-2 on METOP-A and B at mid-morning, and from OMI on AURA in the early afternoon. Consistent retrieval settings are used for all sensors following an algorithm baseline described in De Smedt et al. (2012), which is also the reference algorithm for the future TROPOMI/Sentinel-5 Precursor instrument to be launched in 2015. The satellite columns are validated using MAX-DOAS measurements in Eastern China (Xiang He), Europe (Uccle and OHP) and Equatorial Africa (Bujumbura). We show that the diurnal variation of the formaldehyde column as measured by the MAX-DOAS instruments is well reproduced by the morning and afternoon satellite measurements. This suggests that a good level of inter-sensor consistency has been achieved for H2CO column measurements from GOME-2 and OMI. Furthermore, regional trends in the formaldehyde columns are estimated from the different satellite datasets. Common features are observed such as a decrease of the formaldehyde columns in the Amazonian forest during the last decade, or lower 2009-2011 levels of pollution-related H2CO columns in industrialized regions.

  5. Global Estimates of Fine Particulate Matter Using a Combined Geophysical-Statistical Method with Information from Satellites, Models, and Monitors

    NASA Technical Reports Server (NTRS)

    Van Donkelaar, Aaron; Martin, Randall V.; Brauer, Michael; Hsu, N. Christina; Kahn, Ralph A.; Levy, Robert C.; Lyapustin, Alexei; Sayer, Andrew M.; Winker, David M.

    2016-01-01

    We estimated global fine particulate matter (PM(sub 2.5)) concentrations using information from satellite-, simulation- and monitor-based sources by applying a Geographically Weighted Regression (GWR) to global geophysically-based satellite-derived PM(sub 2.5) estimates. Aerosol optical depth from multiple satellite products (MISR, MODIS Dark Target, MODIS and SeaWiFS Deep Blue, and MODIS MAIAC) was combined with simulation (GEOS-Chem) based upon their relative uncertainties as determined using ground-based sun photometer (AERONET) observations for 1998-2014. The GWR predictors included simulated aerosol composition and land use information. The resultant PM(sub 2.5) estimates were highly consistent (R(sup 2) equals 0.81) with out-of-sample cross-validated PM(sub 2.5) concentrations from monitors. The global population-weighted annual average PM(sub 2.5) concentrations were 3-fold higher than the 10 micrograms per cubic meter WHO guideline, driven by exposures in Asian and African regions. Estimates in regions with high contributions from mineral dust were associated with higher uncertainty, resulting from both sparse ground-based monitoring, and challenging conditions for retrieval and simulation. This approach demonstrates that the addition of even sparse ground-based measurements to more globally continuous PM(sub 2.5) data sources can yield valuable improvements to PM(sub 2.5) characterization on a global scale.

  6. Global Estimates of Fine Particulate Matter using a Combined Geophysical-Statistical Method with Information from Satellites, Models, and Monitors.

    PubMed

    van Donkelaar, Aaron; Martin, Randall V; Brauer, Michael; Hsu, N Christina; Kahn, Ralph A; Levy, Robert C; Lyapustin, Alexei; Sayer, Andrew M; Winker, David M

    2016-04-01

    We estimated global fine particulate matter (PM2.5) concentrations using information from satellite-, simulation- and monitor-based sources by applying a Geographically Weighted Regression (GWR) to global geophysically based satellite-derived PM2.5 estimates. Aerosol optical depth from multiple satellite products (MISR, MODIS Dark Target, MODIS and SeaWiFS Deep Blue, and MODIS MAIAC) was combined with simulation (GEOS-Chem) based upon their relative uncertainties as determined using ground-based sun photometer (AERONET) observations for 1998-2014. The GWR predictors included simulated aerosol composition and land use information. The resultant PM2.5 estimates were highly consistent (R(2) = 0.81) with out-of-sample cross-validated PM2.5 concentrations from monitors. The global population-weighted annual average PM2.5 concentrations were 3-fold higher than the 10 μg/m(3) WHO guideline, driven by exposures in Asian and African regions. Estimates in regions with high contributions from mineral dust were associated with higher uncertainty, resulting from both sparse ground-based monitoring, and challenging conditions for retrieval and simulation. This approach demonstrates that the addition of even sparse ground-based measurements to more globally continuous PM2.5 data sources can yield valuable improvements to PM2.5 characterization on a global scale. PMID:26953851

  7. Investigating the error budget of tropical rainfall accumulations derived from combined passive microwave and infrared satellite measurements

    NASA Astrophysics Data System (ADS)

    Roca, R.; Chambon, P.; jobard, I.; Viltard, N.

    2012-04-01

    Measuring rainfall requires a high density of observations, which, over the whole tropical elt, can only be provided from space. For several decades, the availability of satellite observations has greatly increased; thanks to newly implemented missions like the Megha-Tropiques mission and the forthcoming GPM constellation, measurements from space become available from a set of observing systems. In this work, we focus on rainfall error estimations at the 1 °/1-day accumulated scale, key scale of meteorological and hydrological studies. A novel methodology for quantitative precipitation estimation is introduced; its name is TAPEER (Tropical Amount of Precipitation with an Estimate of ERrors) and it aims to provide 1 °/1-day rain accumulations and associated errors over the whole Tropical belt. This approach is based on a combination of infrared imagery from a fleet of geostationary satellites and passive microwave derived rain rates from a constellation of low earth orbiting satellites. A three-stage disaggregation of error into sampling, algorithmic and calibration errors is performed; the magnitudes of the three terms are then estimated separately. A dedicated error model is used to evaluate sampling errors and a forward error propagation approach is used for an estimation of algorithmic and calibration errors. One of the main findings in this study is the large contribution of the sampling errors and the algorithmic errors of BRAIN on medium rain rates (2 mm h-1 to 10 mm h-1) in the total error budget.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  9. Surface vegetative biomass modelling from combined AVHRR and Landsat satellite data

    NASA Technical Reports Server (NTRS)

    Logan, T. L.; Strahler, A. H.

    1984-01-01

    A methodology for the estimation of regional biomass on the basis of Landsat and Polar Orbiter Satellite Advanced Very High Resolution Radiometer (AVHRR) imagery has been developed by the present study, which concentrated on the Sierra Nevada-Cascade Mountains ecological province of California. The Landsat data are only used initially, to calibrate the AVHRR-based biomass data. The essential element of the present approach is a 'pixel proportions' model. An integer block of Landsat pixels corresponds to each AVHRR pixel. The Landsat pixels are converted into biomass pixels using species biomass expression equations available in the literature.

  10. Global assessment of ocean carbon export by combining satellite observations and food-web models

    NASA Astrophysics Data System (ADS)

    Siegel, D. A.; Buesseler, K. O.; Doney, S. C.; Sailley, S. F.; Behrenfeld, M. J.; Boyd, P. W.

    2014-03-01

    The export of organic carbon from the surface ocean by sinking particles is an important, yet highly uncertain, component of the global carbon cycle. Here we introduce a mechanistic assessment of the global ocean carbon export using satellite observations, including determinations of net primary production and the slope of the particle size spectrum, to drive a food-web model that estimates the production of sinking zooplankton feces and algal aggregates comprising the sinking particle flux at the base of the euphotic zone. The synthesis of observations and models reveals fundamentally different and ecologically consistent regional-scale patterns in export and export efficiency not found in previous global carbon export assessments. The model reproduces regional-scale particle export field observations and predicts a climatological mean global carbon export from the euphotic zone of ~6 Pg C yr-1. Global export estimates show small variation (typically < 10%) to factor of 2 changes in model parameter values. The model is also robust to the choices of the satellite data products used and enables interannual changes to be quantified. The present synthesis of observations and models provides a path for quantifying the ocean's biological pump.

  11. Estimation of the parameters of gravity waves combining ground based and satellite measurements

    NASA Astrophysics Data System (ADS)

    Paulino, Igo; Vadas, Sharon; Buriti, Ricardo; Wrasse, Cristiano M.; Medeiros, Amauri; Takahashi, Hisao; Essien, Patrick

    2016-07-01

    Four medium-scale gravity waves were studied using images of the NIR OH airglow emission obtained from an all sky imager deployed at São João do Cariri (36.5 ^{o}W; 7.4 ^{o}S) and mesospheric temperature profiles from the TIMED/SABER satellite. The coincident measurements were made on 11 and 14 April 2007, 08 February and 28 August 2008. The horizontal parameters of the gravity waves were estimated using the keogram analysis and the vertical ones were calculated from the coincident temperature profiles collected into the area of 15 ^{o} x 15 ^{o} degrees (longitude X latitude), centered at the observatory. The horizontal wavelength were 190, 138, 171 and 355 km, respectively. The observed periods were 50, 20, 33 and 20 min. The vertical wavelength were 15, 10, 15 and 30 km. Comparisons to the dispersion relation for the gravity waves were done and the results are in agreement to the theory. Thus, the SABER satellite measurements may be used to study the gravity wave activity in the mesosphere and lower thermosphere with good precision.

  12. Mean gravity anomalies from a combination of Apollo/ATS 6 and GEOS 3/ATS 6 SST tracking campaigns. [Satellite to Satellite Tracking

    NASA Technical Reports Server (NTRS)

    Kahn, W. D.; Klosko, S. M.; Wells, W. T.

    1982-01-01

    Advances in satellite tracking data accuracy and coverage over the past 15 years have led to major improvements in global geopotential models. But the spacial resolution of the gravity field obtained solely from satellite dynamics sensed by tracking data is still of the order of 1000 km. Attention is given to an approach which will provide information regarding the fine structure of the gravity field on the basis of an application of local corrections to the global field. According to this approach, a basic satellite to satellite tracked (SST) range-rate measurement is constructed from the link between a ground station, a geosynchronous satellite (ATS 6), and a near-earth satellite (Apollo or GEOS 3). Attention is given to a mathematical model, the simulation of SST gravity anomaly estimation accuracies, a gravity anomaly estimation from GEOS 3/ATS 6 and Apollo/ATS 6 SST observations, and an evaluation of the mean gravity anomalies determined from SST.

  13. Mapping Sub-Antarctic Cushion Plants Using Random Forests to Combine Very High Resolution Satellite Imagery and Terrain Modelling

    PubMed Central

    Bricher, Phillippa K.; Lucieer, Arko; Shaw, Justine; Terauds, Aleks; Bergstrom, Dana M.

    2013-01-01

    Monitoring changes in the distribution and density of plant species often requires accurate and high-resolution baseline maps of those species. Detecting such change at the landscape scale is often problematic, particularly in remote areas. We examine a new technique to improve accuracy and objectivity in mapping vegetation, combining species distribution modelling and satellite image classification on a remote sub-Antarctic island. In this study, we combine spectral data from very high resolution WorldView-2 satellite imagery and terrain variables from a high resolution digital elevation model to improve mapping accuracy, in both pixel- and object-based classifications. Random forest classification was used to explore the effectiveness of these approaches on mapping the distribution of the critically endangered cushion plant Azorellamacquariensis Orchard (Apiaceae) on sub-Antarctic Macquarie Island. Both pixel- and object-based classifications of the distribution of Azorella achieved very high overall validation accuracies (91.6–96.3%, κ = 0.849–0.924). Both two-class and three-class classifications were able to accurately and consistently identify the areas where Azorella was absent, indicating that these maps provide a suitable baseline for monitoring expected change in the distribution of the cushion plants. Detecting such change is critical given the threats this species is currently facing under altering environmental conditions. The method presented here has applications to monitoring a range of species, particularly in remote and isolated environments. PMID:23940805

  14. Mapping sub-antarctic cushion plants using random forests to combine very high resolution satellite imagery and terrain modelling.

    PubMed

    Bricher, Phillippa K; Lucieer, Arko; Shaw, Justine; Terauds, Aleks; Bergstrom, Dana M

    2013-01-01

    Monitoring changes in the distribution and density of plant species often requires accurate and high-resolution baseline maps of those species. Detecting such change at the landscape scale is often problematic, particularly in remote areas. We examine a new technique to improve accuracy and objectivity in mapping vegetation, combining species distribution modelling and satellite image classification on a remote sub-Antarctic island. In this study, we combine spectral data from very high resolution WorldView-2 satellite imagery and terrain variables from a high resolution digital elevation model to improve mapping accuracy, in both pixel- and object-based classifications. Random forest classification was used to explore the effectiveness of these approaches on mapping the distribution of the critically endangered cushion plant Azorella macquariensis Orchard (Apiaceae) on sub-Antarctic Macquarie Island. Both pixel- and object-based classifications of the distribution of Azorella achieved very high overall validation accuracies (91.6-96.3%, κ = 0.849-0.924). Both two-class and three-class classifications were able to accurately and consistently identify the areas where Azorella was absent, indicating that these maps provide a suitable baseline for monitoring expected change in the distribution of the cushion plants. Detecting such change is critical given the threats this species is currently facing under altering environmental conditions. The method presented here has applications to monitoring a range of species, particularly in remote and isolated environments. PMID:23940805

  15. Combined evaluation of optical and microwave satellite dataset for soil moisture deficit estimation

    NASA Astrophysics Data System (ADS)

    Srivastava, Prashant K.; Han, Dawei; Islam, Tanvir; Singh, Sudhir Kumar; Gupta, Manika; Gupta, Dileep Kumar; Kumar, Pradeep

    2016-04-01

    Soil moisture is a key variable responsible for water and energy exchanges from land surface to the atmosphere (Srivastava et al., 2014). On the other hand, Soil Moisture Deficit (or SMD) can help regulating the proper use of water at specified time to avoid any agricultural losses (Srivastava et al., 2013b) and could help in preventing natural disasters, e.g. flood and drought (Srivastava et al., 2013a). In this study, evaluation of Moderate Resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) and soil moisture from Soil Moisture and Ocean Salinity (SMOS) satellites are attempted for prediction of Soil Moisture Deficit (SMD). Sophisticated algorithm like Adaptive Neuro Fuzzy Inference System (ANFIS) is used for prediction of SMD using the MODIS and SMOS dataset. The benchmark SMD estimated from Probability Distributed Model (PDM) over the Brue catchment, Southwest of England, U.K. is used for all the validation. The performances are assessed in terms of Nash Sutcliffe Efficiency, Root Mean Square Error and the percentage of bias between ANFIS simulated SMD and the benchmark. The performance statistics revealed a good agreement between benchmark and the ANFIS estimated SMD using the MODIS dataset. The assessment of the products with respect to this peculiar evidence is an important step for successful development of hydro-meteorological model and forecasting system. The analysis of the satellite products (viz. SMOS soil moisture and MODIS LST) towards SMD prediction is a crucial step for successful hydrological modelling, agriculture and water resource management, and can provide important assistance in policy and decision making. Keywords: Land Surface Temperature, MODIS, SMOS, Soil Moisture Deficit, Fuzzy Logic System References: Srivastava, P.K., Han, D., Ramirez, M.A., Islam, T., 2013a. Appraisal of SMOS soil moisture at a catchment scale in a temperate maritime climate. Journal of Hydrology 498, 292-304. Srivastava, P.K., Han, D., Rico

  16. Reduced Toxicity Fuel Satellite Propulsion System Including Axial Thruster and ACS Thruster Combination

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J. (Inventor)

    2001-01-01

    A reduced toxicity fuel satellite propulsion system including a reduced toxicity propellant supply for consumption in an axial class thruster and an ACS class thruster. The system includes suitable valves and conduits for supplying the reduced toxicity propellant to the ACS decomposing element of an ACS thruster. The ACS decomposing element is operative to decompose the reduced toxicity propellant into hot propulsive gases. In addition the system includes suitable valves and conduits for supplying the reduced toxicity propellant to an axial decomposing element of the axial thruster. The axial decomposing element is operative to decompose the reduced toxicity propellant into hot gases. The system further includes suitable valves and conduits for supplying a second propellant to a combustion chamber of the axial thruster, whereby the hot gases and the second propellant auto-ignite and begin the combustion process for producing thrust.

  17. Diurnal Variability of Tropical Rainfall Retrieved from Combined GOES and TRMM Satellite Information.

    NASA Astrophysics Data System (ADS)

    Sorooshian, S.; Gao, X.; Hsu, K.; Maddox, R. A.; Hong, Y.; Gupta, H. V.; Imam, B.

    2002-05-01

    Recent progress in satellite remote-sensing techniques for precipitation estimation, along with more accurate tropical rainfall measurements from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and precipitation radar (PR) instruments, have made it possible to monitor tropical rainfall diurnal patterns and their intensities from satellite information. One year (August 1998-July 1999) of tropical rainfall estimates from the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) system were used to produce monthly means of rainfall diurnal cycles at hourly and 1° × 1° scales over a domain (30°S-30°N, 80°E-10°W) from the Americas across the Pacific Ocean to Australia and eastern Asia.The results demonstrate pronounced diurnal variability of tropical rainfall intensity at synoptic and regional scales. Seasonal signals of diurnal rainfall are presented over the large domain of the tropical Pacific Ocean, especially over the ITCZ and South Pacific convergence zone (SPCZ) and neighboring continents. The regional patterns of tropical rainfall diurnal cycles are specified in the Amazon, Mexico, the Caribbean Sea, Calcutta, Bay of Bengal, Malaysia, and northern Australia. Limited validations for the results include comparisons of 1) the PERSIANN-derived diurnal cycle of rainfall at Rondonia, Brazil, with that derived from the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) radar data; 2) the PERSIANN diurnal cycle of rainfall over the western Pacific Ocean with that derived from the data of the optical rain gauges mounted on the TOGA-moored buoys; and 3) the monthly accumulations of rainfall samples from the orbital TMI and PR surface rainfall with the accumulations of concurrent PERSIANN estimates. These comparisons indicate that the PERSIANN-derived diurnal patterns at the selected resolutions produce estimates that are similar in magnitude and phase.

  18. All-weather estimates of the land surface skin temperatures from combined analyses of microwave and infrared satellite observations

    NASA Astrophysics Data System (ADS)

    Jimenez, C.; Aires, F.; Prigent, C.; Catherinot, J.; Rossow, W. B.

    2011-12-01

    The surface skin temperature (Ts) is a key parameter at the land-atmosphere interface. Global datasets of Ts are traditionally estimated from satellite infrared radiance observations, under clear sky conditions. First, the inter-comparison of different IR land surface temperature satellite datasets (ISCCP, MODIS, and AIRS) is presented, along with an evaluation with in situ measurements at selected stations archived during CEOP (Coordinated Enhanced Observing Period). The objective is to assess the accuracy of the Ts estimates, and to evidence the major error sources in the retrieval. Results show that the major sources of differences between the different satellite products come from instrument calibration differences, especially for high Ts, followed by the impact of the water vapor treatment in the algorithm, and the differences in surface emissivities. The main limitation of satellite infrared measurements of Ts is their inability to penetrate clouds, limiting them to clear conditions. Microwave wavelengths, being much less affected by clouds than the infrared, are an attractive alternative in cloudy regions as they can be used to derive an all-sky skin Ts product. A neural network inversion scheme has been developed to retrieve surface Ts along with atmospheric water vapor, cloud liquid water, and surface emissivities over land from a combined analysis of Special Sensor Microwave /Imager (SSM/I) and International Satellite Cloud Climatology Project (ISCCP) data. In the absence of routine in situ Ts measurements, retrieved all-weather Ts values are first evaluated globally by comparison to the surface air temperature (Tair) measured by the meteorological station network. The Ts-Tair difference from the global comparisons showed all the expected variations with solar flux, soil characteristics, and cloudiness. This evaluation has been recently extended locally at a few sites by using the Ts in-situ measurements from several CEOP stations representing different

  19. Constraining methane emissions from the Indo-Gangetic Plains and South Asia using combined surface and satellite data

    NASA Astrophysics Data System (ADS)

    Ganesan, A.; Lunt, M. F.; Rigby, M. L.; Chatterjee, A.; Boesch, H.; Parker, R.; Prinn, R. G.; van der Schoot, M. V.; Krummel, P. B.; Tiwari, Y. K.; Mukai, H.; Machida, T.; Terao, Y.; Nomura, S.; Patra, P. K.

    2015-12-01

    We present an analysis of the regional methane (CH4) budget from South Asia, using new measurements and new modelling techniques. South Asia contains some of the largest anthropogenic CH4 sources in the world, mainly from rice agriculture and ruminants. However, emissions from this region have been highly uncertain largely due to insufficient constraints from atmospheric measurements. Compared to parts of the developed world, which have well-developed monitoring networks, South Asia is very under-sampled, particularly given its importance to the global CH4 budget. Over the past few years, data have been collected from a variety of surface sites around the region, ranging from in situ to flask-based sampling. We have used these data, in conjunction with column methane data from the GOSAT satellite, to quantify emissions at a regional scale. Using the Met Office's Lagrangian NAME model, we calculated sensitivities to surface fluxes at 12 km resolution, allowing us to simulate the high-resolution impacts of emissions on concentrations. In addition, we used a newly developed hierarchical Bayesian inverse estimation scheme to estimate regional fluxes over the period of 2012-2014 in addition to ancillary "hyper-parameters" that characterize uncertainties in the system. Through this novel approach, we have characterized the effect of "aggregation" errors, model uncertainties as well as the effects of correlated errors when using regional measurement networks. We have also assessed the effects of biases on the GOSAT CH4 retrievals, which has been made possible for the first time for this region through the expanded surface measurements. In this talk, we will discuss a) regional CH4 fluxes from South Asia, with a particular focus on the densely populated Indo-Gangetic Plains b) derived model uncertainties, including the effects of correlated errors c) the impacts of combining surface and satellite data for emissions estimation in regions where poor satellite validation

  20. Comprehensive Spectral Signal Investigation of a Larch Forest Combining - and Satellite-Based Measurements

    NASA Astrophysics Data System (ADS)

    Landmann, J. M.; Rutzinger, M.; Bremer, M.; chmidtner, K.

    2016-06-01

    Collecting comprehensive knowledge about spectral signals in areas composed by complex structured objects is a challenging task in remote sensing. In the case of vegetation, shadow effects on reflectance are especially difficult to determine. This work analyzes a larch forest stand (Larix decidua MILL.) in Pinnis Valley (Tyrol, Austria). The main goal is extracting the larch spectral signal on Landsat 8 (LS8) Operational Land Imager (OLI) images using ground measurements with the Cropscan Multispectral Radiometer with five bands (MSR5) simultaneously to satellite overpasses in summer 2015. First, the relationship between field spectrometer and OLI data on a cultivated grassland area next to the forest stand is investigated. Median ground measurements for each of the grassland parcels serve for calculation of the mean difference between the two sensors. Differences are used as "bias correction" for field spectrometer values. In the main step, spectral unmixing of the OLI images is applied to the larch forest, specifying the larch tree spectral signal based on corrected field spectrometer measurements of the larch understory. In order to determine larch tree and shadow fractions on OLI pixels, a representative 3D tree shape is used to construct a digital forest. Benefits of this approach are the computational savings compared to a radiative transfer modeling. Remaining shortcomings are the limited capability to consider exact tree shapes and nonlinear processes. Different methods to implement shadows are tested and spectral vegetation indices like the Normalized Difference Vegetation Index (NDVI) and Greenness Index (GI) can be computed even without considering shadows.

  1. Spectral assessment of isostatic gravity models against CHAMP, GRACE, GOCE satellite-only and combined gravity models

    NASA Astrophysics Data System (ADS)

    Tsoulis, Dimitrios; Patlakis, Konstantinos

    2014-08-01

    The availability of digital elevation databases representing the topographic and bathymetric relief with global homogeneous coverage and increasing resolution permits the computation of crust-related Earth gravity models, the so-called topographic/isostatic Earth gravity models (henceforth T/I models). Although expressing the spherical harmonic content of the topographic masses, the interpretation purpose of T/I models has not been given the attention it deserves, apart from the fact that they express some degree of compensation to the observed spectrum of the topographic heights, depending on the kind of the applied compensation mechanism. The present contribution attempts to improve the interpretation aspects of T/I Earth gravity models. To this end, a rigorous spectral assessment is performed to a standard Airy/Heiskanen T/I model against different CHAllenging Minisatellite Payload (CHAMP), Gravity Recovery and Climate Experiment (GRACE), Gravity field and steadystate Ocean Circulation Explorer (GOCE) satellite-only, and combined gravity models. Different correlation bandwidths emerge for these four groups of satellite-based gravity models. The band-limited forward computation of the models using these bandwidths reproduces nicely the main features of the applied T/I model.

  2. Estimation of evaporation over the upper Blue Nile basin by combining observations from satellites and river flow gauges

    NASA Astrophysics Data System (ADS)

    Allam, Mariam M.; Jain Figueroa, Anjuli; McLaughlin, Dennis B.; Eltahir, Elfatih A. B.

    2016-02-01

    Reliable estimates of regional evapotranspiration are necessary to improve water resources management and planning. However, direct measurements of evaporation are expensive and difficult to obtain. Some of the difficulties are illustrated in a comparison of several satellite-based estimates of evapotranspiration for the Upper Blue Nile (UBN) basin in Ethiopia. These estimates disagree both temporally and spatially. All the available data products underestimate evapotranspiration leading to basin-scale mass balance errors on the order of 35 percent of the mean annual rainfall. This paper presents a methodology that combines satellite observations of rainfall, terrestrial water storage as well as river-flow gauge measurements to estimate actual evapotranspiration over the UBN basin. The estimates derived from these inputs are constrained using a one-layer soil water balance and routing model. Our results describe physically consistent long-term spatial and temporal distributions of key hydrologic variables, including rainfall, evapotranspiration, and river-flow. We estimate an annual evapotranspiration over the UBN basin of about 2.55 mm per day. Spatial and temporal evapotranspiration trends are revealed by dividing the basin into smaller subbasins. The methodology described here is applicable to other basins with limited observational coverage that are facing similar future challenges of water scarcity and climate change.

  3. Development of a Biomass Burning Emissions Inventory by Combining Satellite and Ground-based Information

    EPA Science Inventory

    A 2005 biomass burning (wildfire, prescribed, and agricultural) emission inventory has been developed for the contiguous United States using a newly developed simplified method of combining information from multiple sources for use in the US EPA’s national Emission Inventory (NEI...

  4. Combined SAR/IR satellite data and circulation model analysis of upwelling in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Lehmann, A.; Gurova, E.

    2012-04-01

    Cold upwelled water can impose significant changes in the stability of the marine boundary layer as well as in surface water density relative to surrounding waters. Lower wind stress caused by increased stability over colder and denser water contributes to produce lower sea roughness and often creating areas of lower signal values in SAR imagery with sharp or soft gradients to surrounding waters with high resolution details of hydrodynamic features. In other cases upwelling appears on SAR images as an area of alternate dark and light stripes perpendicularly to the coastline, not overlapping with SST contours at all. The appearance of upwelling on SAR and SST can have varied correlation because of other factors affecting SAR imaging - a very detailed view in one area can be replaced by nothing in a neighboring zone. High surface concentrations of floating cyanobacteria during summer blooms also cause changes in roughness and can affect imaging of upwelling on SAR. Such areas of cyanobacteria accumulations can be detected by the use of optical remote sensing data like MODIS under cloud free conditions. To further investigate upwelling events detected by SAR/IR satellite imaging a high resolution coupled sea ice-ocean model of the Baltic Sea has been utilized. The model is able to simulate upwelling events realistically. Over upwelling areas the wind stress is significantly reduced if the mean wind speed is below a certain threshold. The utilization of modeled hydrodynamics and wind stress data together with SAR, SST and optical remote sensing information provides an extended analysis of the upwelling event itself, as well as a deeper understanding of upwelling appearance on SAR images.

  5. Combined system for the compensation of the solar pressure-induced disturbing torque for geostationary satellites

    NASA Astrophysics Data System (ADS)

    Shmatov, S. I.; Mordvinkin, A. S.

    2014-12-01

    The problem is considered of determining the shape and dimensions of the passive component in a combined system for offsetting the solar pressure-induced disturbing torque for geostationary spacecraft with asymmetrical solar arrays. The problem statement, numerical solution algorithm, and calculated results are presented. The resulting shape, the study suggests, not only has the required compensation properties but is also the most efficient from the standpoint of manufacture and functional reliability.

  6. Combining Satellite and Ground Observations for IRI-related Plasmasphere-Ionosphere Modeling

    NASA Astrophysics Data System (ADS)

    Reinisch, B. W.; Nsumei, P.; Huang, X.; Bilitza, D.

    2006-12-01

    Improved representation of F layer topside and plasmasphere electron density and temperature in the International Reference Ionosphere (IRI) [Bilitza, Radio Sci., 38(6), 261-275, 2001] are the goal of a new LWS TR&T tools project -TOPLA. Measurements by the radio plasma imager (RPI) on the IMAGE satellite [Reinisch et al., Geophys. Res. Ltts., 28, 24, 4521-4524, 2001] provide electron density profiles of the plasmasphere down to altitudes of ~3000 km. Groundbased observations with ionosondes and incoherent scatter radars led to empirical electron density models of the ionosphere like the IRI. We discuss the use of a Chapman-like function with a scale height that varies continuously with height, the "vary-Chap" function, for connecting the RPI plasmasphere density profile to the ionosphere profile above hmF2. While the original Chapman theory assumed the scale height of the neutral EUV-absorbing gas (atomic oxygen) to be constant, we allow it to vary with height, initially slowly near hmF2 [Reinisch et al., Adv. Space Res., 34, 2026-2031, 2004], and then rapidly at altitudes where [O] is replaced by [H] and/or [He] as the dominant species. A hyperbolic tangent function suitably represents this variation; we use it to parameterize the scale height function in terms of the transition height hT, the scale height HT at hT, and a parameter b characterizing the steepness of the transition. We also make use of ISIS 2 topside sounder profiles [Huang et al., Annali di Geofisica, 45 (1), 125-130, 2002] to develop an F2 topside-to-plasmasphere Ne model (TOPLA). The large database of ISIS profiles makes it possible to statistically evaluate the behavior of the scale height parameters hT, HT, and b, and show their dependence on season and latitude. In addition to electron density, the TOPLA modeling project includes an effort to improve the electron temperature Te profile for the IRI model in the topside ionosphere and an extension to the plasmasphere. A first step is to include

  7. Global precipitation estimates based on a technique for combining satellite-based estimates, rain gauge analysis, and NWP model precipitation information

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Rudolf, Bruno; Schneider, Udo; Keehn, Peter R.

    1995-01-01

    The 'satellite-gauge model' (SGM) technique is described for combining precipitation estimates from microwave satellite data, infrared satellite data, rain gauge analyses, and numerical weather prediction models into improved estimates of global precipitation. Throughout, monthly estimates on a 2.5 degrees x 2.5 degrees lat-long grid are employed. First, a multisatellite product is developed using a combination of low-orbit microwave and geosynchronous-orbit infrared data in the latitude range 40 degrees N - 40 degrees S (the adjusted geosynchronous precipitation index) and low-orbit microwave data alone at higher latitudes. Then the rain gauge analysis is brougth in, weighting each field by its inverse relative error variance to produce a nearly global, observationally based precipitation estimate. To produce a complete global estimate, the numerical model results are used to fill data voids in the combined satellite-gauge estimate. Our sequential approach to combining estimates allows a user to select the multisatellite estimate, the satellite-gauge estimate, or the full SGM estimate (observationally based estimates plus the model information). The primary limitation in the method is imperfections in the estimation of relative error for the individual fields. The SGM results for one year of data (July 1987 to June 1988) show important differences from the individual estimates, including model estimates as well as climatological estimates. In general, the SGM results are drier in the subtropics than the model and climatological results, reflecting the relatively dry microwave estimates that dominate the SGM in oceanic regions.

  8. Improved 3D density modelling of the Central Andes from combining terrestrial datasets with satellite based datasets

    NASA Astrophysics Data System (ADS)

    Schaller, Theresa; Sobiesiak, Monika; Götze, Hans-Jürgen; Ebbing, Jörg

    2015-04-01

    As horizontal gravity gradients are proxies for large stresses, the uniquely high gravity gradients of the South American continental margin seem to be indicative for the frequently occurring large earthquakes at this plate boundary. It has been observed that these earthquakes can break repeatedly the same respective segment but can also combine to form M>9 earthquakes at the end of longer seismic cycles. A large seismic gap left behind by the 1877 M~9 earthquake existed in the northernmost part of Chile. This gap has partially been ruptured in the Mw 7.7 2007 Tocopilla earthquake and the Mw 8.2 2014 Pisagua earthquake. The nature of this seismological segmentation and the distribution of energy release in an earthquake is part of ongoing research. It can be assumed that both features are related to thickness variations of high density bodies located in the continental crust of the coastal area. These batholiths produce a clear maximum in the gravity signal. Those maxima also show a good spatial correlation with seismic asperity structures and seismological segment boundaries. Understanding of the tectonic situation can be improved through 3D forward density modelling of the gravity field. Problems arise in areas with less ground measurements. Especially in the high Andes severe gaps exist due to the inaccessibility of some regions. Also the transition zone between on and offshore date data displays significant problems, particularly since this is the area that is most interesting in terms of seismic hazard. We modelled the continental and oceanic crust and upper mantle using different gravity datasets. The first one includes terrestrial data measured at a station spacing of 5 km or less along all passable roads combined with satellite altimetry data offshore. The second data set is the newly released EIGEN-6C4 which combines the latest satellite data with ground measurements. The spherical harmonics maximum degree of EIGEN-6C4 is 2190 which corresponds to a

  9. On the combined use of high temporal resolution, optical satellite data for flood monitoring and mapping: a possible contribution from the RST approach

    NASA Astrophysics Data System (ADS)

    Faruolo, M.; Coviello, I.; Lacava, T.; Pergola, N.; Tramutoli, V.

    2009-04-01

    Among natural disasters, floods are ones of those more common and devastating, often causing high environmental, economical and social costs. When a flooding event occurs, timely information about precise location, extent, dynamic evolution, etc., is highly required in order to effectively support civil protection activities aimed at managing the emergency. Satellite remote sensing may represent a supplementary information source, providing mapping and continuous monitoring of flooding extent as well as a quick damage assessment. Such purposes need frequently updated satellite images as well as suitable image processing techniques, able to identify flooded areas with reliability and timeliness. Recently, an innovative satellite data analysis approach (named RST, Robust Satellite Technique) has been applied to NOAA-AVHRR (Advanced Very High Resolution Radiometer) satellite data in order to dynamically map flooded areas. Thanks to a multi-temporal analysis of co-located satellite records and an automatic change detection scheme, such an approach allows to overcome major drawbacks related to the previously proposed methods (mostly not automatic and based on empirically chosen thresholds, often affected by false identifications). In this paper, RST approach has been for the first time applied to both AVHRR and EOS/MODIS (Moderate Resolution Imaging Spectroradiometer) data, in order to assess its potential - in flooded area mapping and monitoring - on different satellite packages characterized by different spectral and spatial resolutions. As a study case, the flooding event which hit the Europe in August 2002 has been selected. Preliminary results shown in this study seem to confirm the potential of such an approach in providing reliable and timely information, useful for near real time flood hazard assessment and monitoring, using both MODIS and AVHRR data. Moreover, the combined use of information coming from both satellite packages (easily achievable thanks to the

  10. Study of cloud properties and processes in the polar regions by combining satellite and ground-based remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Adhikari, Loknath

    Clouds in the polar regions play an important roles in the hydrologic cycle, the local radiative balance, and polar sea ice. However, harsh climatic conditions and perennial snow and ice cover limits the collection of cloud data from the surface as well as the effectiveness of cloud detection with satellite passive sensors. Therefore, there is a lack of reliable data on polar clouds and their properties. This study combines active and passive measurements from the NASA A-Train satellites to overcome these shortcomings and to provide a novel approach to study on polar clouds. Multi-year CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data are used to investigate the characteristics of tropospheric clouds and precipitation systems, and their effect on the occurrence and microphysical properties of polar stratospheric clouds in the Antarctic region, south of 60 °S. The lidar and radar data are collocated to derive a combined cloud mask to improve detection of cloud vertical structure. Polar stratospheric clouds were detected using CALIPSO attenuated lidar scattering ratios (ALSR) at a horizontal resolution of 20 km to achieve good signal-to-noise ratios to allow the detection of tenuous PSCs. Clouds in the Antarctic region exhibit distinct land-sea and seasonal variabilities. The mean annual cloud occurrence is ~ 50 % over the continent and ~ 85 % over the ocean. Over the ocean the mean occurrence is higher in summer (90 %) than in winter (70 %). Low-level clouds contribute to more than 60 % of the total clouds. However, due to the extensive snow cover and cold surfaces in winter these low-level cloud occurrences are smaller in winter (50 %) than in summer (65 %). For ice clouds, both the effective radius and ice water content are larger in summer than in winter. High-level and deep tropospheric clouds strongly affect polar stratospheric cloud (PSC) occurrence and their microphysical properties by providing additional cooling

  11. Assessing irrigated agriculture's surface water and groundwater consumption by combining satellite remote sensing and hydrologic modelling.

    PubMed

    Peña-Arancibia, Jorge L; Mainuddin, Mohammed; Kirby, John M; Chiew, Francis H S; McVicar, Tim R; Vaze, Jai

    2016-01-15

    Globally, irrigation accounts for more than two thirds of freshwater demand. Recent regional and global assessments indicate that groundwater extraction (GWE) for irrigation has increased more rapidly than surface water extraction (SWE), potentially resulting in groundwater depletion. Irrigated agriculture in semi-arid and arid regions is usually from a combination of stored surface water and groundwater. This paper assesses the usefulness of remotely-sensed (RS) derived information on both irrigation dynamics and rates of actual evapotranspiration which are both input to a river-reach water balance model in order to quantify irrigation water use and water provenance (either surface water or groundwater). The assessment is implemented for the water-years 2004/05-2010/11 in five reaches of the Murray-Darling Basin (Australia); a heavily regulated basin with large irrigated areas and periodic droughts and floods. Irrigated area and water use are identified each water-year (from July to June) through a Random Forest model which uses RS vegetation phenology and actual evapotranspiration as predicting variables. Both irrigated areas and actual evapotranspiration from irrigated areas were compared against published estimates of irrigated areas and total water extraction (SWE+GWE).The river-reach model determines the irrigated area that can be serviced with stored surface water (SWE), and the remainder area (as determined by the Random Forest Model) is assumed to be supplemented by groundwater (GWE). Model results were evaluated against observed SWE and GWE. The modelled SWE generally captures the observed interannual patterns and to some extent the magnitudes, with Pearson's correlation coefficients >0.8 and normalised root-mean-square-error<30%. In terms of magnitude, the results were as accurate as or better than those of more traditional (i.e., using areas that fluctuate based on water resource availability and prescribed crop factors) irrigation modelling. The RS

  12. Global aerosol typing from a combination of A-Train satellite observations in clear-sky and above clouds

    NASA Astrophysics Data System (ADS)

    Kacenelenbogen, M. S.; Russell, P. B.; Vaughan, M.; Redemann, J.; Shinozuka, Y.; Livingston, J. M.; Zhang, Q.

    2014-12-01

    According to the 5th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the model estimates of Radiative Forcing due to aerosol-radiation interactions (RFari) for individual aerosol types are less certain than the total RFari [Boucher et al., 2013]. For example, the RFari specific to Black Carbon (BC) is uncertain due to an underestimation of its mass concentration near source regions [Koch et al., 2009]. Several recent studies have evaluated chemical transport model (CTM) predictions using observations of aerosol optical properties such as Aerosol Optical Depth (AOD) or Single Scattering Albedo (SSA) from satellite or ground-based instruments (e.g., Huneeus et al., [2010]). However, most passive remote sensing instruments fail to provide a comprehensive assessment of the particle type without further analysis and combination of measurements. To improve the predictions of aerosol composition in CTMs, we have developed an aerosol classification algorithm (called Specified Clustering and Mahalanobis Classification, SCMC) that assigns an aerosol type to multi-parameter retrievals by spaceborne, airborne or ground based passive remote sensing instruments [Russell et al., 2014]. The aerosol types identified by our scheme are pure dust, polluted dust, urban-industrial/developed economy, urban-industrial/developing economy, dark biomass smoke, light biomass smoke and pure marine. First, we apply the SCMC method to five years of clear-sky space-borne POLDER observations over Greece. We then use the aerosol extinction and SSA spectra retrieved from a combination of MODIS, OMI and CALIOP clear-sky observations to infer the aerosol type over the globe in 2007. Finally, we will extend the spaceborne aerosol classification from clear-sky to above low opaque water clouds using a combination of CALIOP AOD and backscatter observations and OMI absorption AOD values from near-by clear-sky pixels.

  13. The efficacy of combining satellite water storage and soil moisture observations as constraints on water balance estimation

    NASA Astrophysics Data System (ADS)

    Tian, Siyuan; van Dijk, Albert; Renzullo, Luigi; Tregoning, Paul; Walker, Jeffrey; Pauwels, Valentijn

    2016-04-01

    The ability to accurately estimate terrestrial water storage (TWS) and its components (e.g. soil moisture, groundwater, surface water and snow) is of considerable value to water resources assessment. Due to the imperfection of both model predictions and observations, data assimilation methods have been widely applied to hydrological problems for optimal combination of model and observations. Recent studies on the assimilation of TWS data have shown its capability to improve simulated groundwater storages, but the assimilation of TWS only does not guarantee accurate estimation of surface soil moisture (SSM). We investigated the efficiency of data assimilation combining TWS change estimates, derived from temporal changes in Earth's gravity field measured by the Gravity Recovery and Climate Experiment (GRACE), with SSM, retrieved from emitted microwave radiation at L-band observed by the Soil Moisture and Ocean Salinity (SMOS) satellite. The global World Wide Water (W3) water balance model was used. The specific satellite data products used were the SMOS CATDS level 3 daily SSM product and the JPL mascon monthly GRACE product. Both the ensemble Kalman filter (EnKF) and smoother (EnKS) were implemented to determine the best option for the assimilation of SSM observations only and the joint assimilation of SSM and TWS. The observation models, which map model states into observation space, are the top-layer soil relative wetness and monthly average TWS (i.e. aggregated daily top-, shallow-, deep-layer soil water storage, ground- and surface water storages). Three assimilation experiments were conducted with each method: a) assimilation of SSM data only; b) assimilation of TWS data only; c) joint assimilation of SSM and TWS data. Results were compared against in-situ soil moisture and groundwater observations, and the performance assessed with respect to open-loop results. Results for the Murray-Darling Basin in Australia demonstrate that the assimilation of SSM data only

  14. Combining Ground-based and Satellite Observations to Reconstruct Changes in the Functioning of the Terrestrial Biosphere

    NASA Astrophysics Data System (ADS)

    Cox, P. M.; Groenendijk, M.

    2014-12-01

    Vegetation links the planet's water and carbon cycles. Stomata on plant leaves are the pores through which CO2 is fixed during photosynthesis, and also the pores through which water is returned to the atmosphere as the transpiration flux. Stomata therefore exert considerable control over both the water and carbon cycles. Unfortunately, the long-term responses of stomata to rising CO2 and changes in climate are still rather uncertain, despite their significance for future climate. In contrast, Plant Water Use Efficiency (WUE) which is the ratio of the carbon assimilated through photosynthesis to the water lost through transpiration, is a robust diagnostic of the functioning of the land biosphere that is not directly dependent on the uncertain long-term responses of stomata. We have recently shown that it is possible to get constrained estimates of fractional changes in WUE based purely on changes in atmospheric CO2 and near surface temperature and humidity. This is achieved by calibrating against eddy covariance flux measurements (that constrain the response of WUE to humidity deficit), and also d13C records from tree-rings (that constrain the CO2-sensitivity of WUE). This talk will show how these ground-based measurements imply very significant changes in WUE, both globally and regionally, from 1900 onwards. Furthermore, we will show how the combination of our reconstructed changes in WUE with satellite-based estimates of Gross Primary Productivity, enable recent changes in plant transpiration to be estimated.

  15. Combining satellite remote sensing and surveys to understand persistent yield variation--- a case study in North China Plain

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Lobell, D. B.; Chen, X.

    2015-12-01

    A large gap between maize yields on average farmers' fields and the highest yields achieved by either experiment or farmers is typical throughout the developing world, including in the North China Plain (NCP). This maize yield gap as identified by previous studies indicates large opportunities for raising yield by improving agronomy. Quzhou county is typical of the winter-wheat summer-maize system in NCP where the average plot size is as small as 0.25 hectares. To analyze this cropping system amidst the challenge of substantial heterogeneity, we identified fields that were either persistently higher or lower yielding according to the remote sensing yield estimates, and then conducted detailed field surveys. We found irrigation facility to be a major constraint to yield both in terms of irrigation water quality and farmers' access to wells. In total, improving the access to unsalty water would be associated with a 0.32t/ha (4.2%) increase in multi-year average yield. In addition, farmers' method of choosing cultivar, which likely relates to their overall knowledge level, significantly explained yield variation. In particular, those choosing cultivars according to technician advice, personal experiences and high yielding neighbors' advice had on average higher yield than farmers that either followed seed sellers' advice or collectively purchased seeds. Overall, the study presents a generalizable methodology of assessing yield gap as well as its persistent factors using a combination of satellite and survey data.

  16. Combining In SITU And Multi-Sensor Satellite Data To Assess The Impact Of Atmospheric Deposition In Lake Garda

    NASA Astrophysics Data System (ADS)

    Giardino, Claudia; Bresciani, Mariano; Cazzaniga, Ilaria; Di Nicolantonio, Walter; Cacciari, Alessandra; Matta, Erica; Rampini, Anna; Gianinetto, Marco; Ober, Giovanna

    2013-12-01

    In this study we investigated the effect of the deposition of Saharan dust on the phytoplankton growth (i.e. dust fertilization hypothesis) in Lake Garda, an oligotrophic basin with low nutrient and low chlorophyll-a (chl-a) concentration, by combining satellite data with in situ measurements. A Saharan dust event has been recognised on 28/07/2005 by: (i) SEVIRI (Spinning Enhanced Visible and InfraRed Imager) data processing, (ii) a significant increase of PM10 with respect to PM2.5 in a site southern the lake; and (iii) the high values of AOT (aerosol optical thickness) with corresponding low values of the Angstrom parameter measured by AERONET in Ispra. Few days later, an increase of chl-a in the lake was detected from MERIS (Medium Resolution Imaging Spectrometer). The images were processed with the Case-2 Regional (C2R) processor that provided values comparable to in situ measurements (r=0.78). Therefore, preliminary results seem to indicate a response of the Lake Garda in terms of increasing of chl-a as a consequence of the Saharan dust event recognised on 28/07/2005. Nevertheless, the analysis of further events is mandatory in order to have confirmation (or no), about the linkage between atmospheric deposition and phytoplankton dynamics in the study area.

  17. Global Electric Circuit Implications of Combined Aircraft Storm Electric Current Measurements and Satellite-Based Diurnal Lightning Statistics

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.

    2011-01-01

    Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of thunderstorms and electrified shower clouds (ESCs) spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, and with positive and negative fields above the storms. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean thunderstorms is 1.7 A while the mean current for land thunderstorms is 1.0 A. The mean current for ocean ESCs 0.41 A and the mean current for land ESCs is 0.13 A. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal flash rate statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie curve) to within 4% for all but two short periods of time. The agreement with the Carnegie curve was obtained without any tuning or adjustment of the satellite or aircraft data. Given our data and assumptions, mean contributions to the global electric circuit are 1.1 kA (land) and 0.7 kA (ocean) from thunderstorms, and 0.22 kA (ocean) and 0.04 (land) from ESCs, resulting in a mean total conduction current estimate for the global electric circuit of 2.0 kA. Mean storm counts are 1100 for land

  18. IMPROVING THE ACCURACY OF HISTORIC SATELLITE IMAGE CLASSIFICATION BY COMBINING LOW-RESOLUTION MULTISPECTRAL DATA WITH HIGH-RESOLUTION PANCHROMATIC DATA

    SciTech Connect

    Getman, Daniel J

    2008-01-01

    Many attempts to observe changes in terrestrial systems over time would be significantly enhanced if it were possible to improve the accuracy of classifications of low-resolution historic satellite data. In an effort to examine improving the accuracy of historic satellite image classification by combining satellite and air photo data, two experiments were undertaken in which low-resolution multispectral data and high-resolution panchromatic data were combined and then classified using the ECHO spectral-spatial image classification algorithm and the Maximum Likelihood technique. The multispectral data consisted of 6 multispectral channels (30-meter pixel resolution) from Landsat 7. These data were augmented with panchromatic data (15m pixel resolution) from Landsat 7 in the first experiment, and with a mosaic of digital aerial photography (1m pixel resolution) in the second. The addition of the Landsat 7 panchromatic data provided a significant improvement in the accuracy of classifications made using the ECHO algorithm. Although the inclusion of aerial photography provided an improvement in accuracy, this improvement was only statistically significant at a 40-60% level. These results suggest that once error levels associated with combining aerial photography and multispectral satellite data are reduced, this approach has the potential to significantly enhance the precision and accuracy of classifications made using historic remotely sensed data, as a way to extend the time range of efforts to track temporal changes in terrestrial systems.

  19. The homogeneous/ Heterogeneous data weighting method of LEO combined orbit determination based on BI-satellite positioning system with its application

    NASA Astrophysics Data System (ADS)

    Zhao, D. Y.; Pan, X. G.; Wang, J. Q.; Wang, Z. M.

    2008-01-01

    Aiming at combined orbit determination (COD) multi-source data fusion for low earth orbit (LEO) based on bi-satellite positioning system (BPS), an improved variance component estimation (VCE) optimal weighting method of homogeneous data is established with two-step system errors correction. And then an integrated optimal weighting method based on model structure characteristics analysis and VCE estimation of heterogeneous data is put forward by analyzing the essence of multi-source fusion measure model which is a multi-structural, multi-parametric, non-linear regression model. Then the algorithm of optimal weighting and COD parameters estimation is designed, and two kinds of COD simulation experiments are carried out by processing homogeneous data of bi-satellite range sum and its back-up satellite data, heterogeneous data of bi-satellite range sum data and star sensor angle data. Theoretical analysis and simulation computations show that improved VCE method based on two-step system errors correction can gain higher precision than that of traditional experience weighting method for COD of homogeneous data weighting. At the same time, by introducing weighting factor which denotes model structure characteristics and proves the designed optimal weighting algorithm, the amelioration of COD precision of LEO and bi-satellite gain to some extent is feasible from practical application.

  20. A practical small satellite variable-speed control moment gyroscope for combined energy storage and attitude control

    NASA Astrophysics Data System (ADS)

    Richie, David J.; Lappas, Vaios J.; Prassinos, George

    2009-12-01

    A recent effort to develop single-gimbal variable-speed control moment gyroscopes (VSCMGs) for a combined energy storage and attitude control subsystem (ESACS) on small satellites has culminated in laboratory validation of the concept. A single actuator prototype comprised of a cutting-edge Carbon Fiber rotor and COTS motor/generator components has been developed, balanced, bench tested, and integrated onto a spherical air-bearing structure. This structure is used to demonstrate the primary capability of a VSCMG to act as a dynamo whilst simultaneously changing a spacecraft's orientation in a controlled fashion. As originally predicted, the actuator's flywheel spins up when energy is supplied (supported via a direct energy transfer power architecture), then spins down when the energy source is removed, porting the energy released to run a resistive load. The work presented gives an overview of the governing principles of the technology, addresses the underlying mission and design requirements, and presents the prototype design. Then, effectiveness of the prototype integrated on a three-axis test article is presented along with its associated test data. Finally, discussion of these results and identification of future research concludes the work. The benefits of this technology for future space missions are that system consolidation permits mass reduction, higher instantaneous peak power is available as compared to conventional secondary battery systems, state-of-charge measurement is readily available from wheel speed feedback, and torque amplification through gimballing permits efficient actuator control. The technology demonstrated is exciting and leaves the door open for future development via inclusion of magnetic levitation.

  1. Mineral dust impact on snow radiative properties in the European Alps combining ground, UAV, and satellite observations

    NASA Astrophysics Data System (ADS)

    Di Mauro, B.; Fava, F.; Ferrero, L.; Garzonio, R.; Baccolo, G.; Delmonte, B.; Colombo, R.

    2015-06-01

    In this paper, we evaluate the impact of mineral dust (MD) on snow radiative properties in the European Alps at ground, aerial, and satellite scale. A field survey was conducted to acquire snow spectral reflectance measurements with an Analytical Spectral Device (ASD) Field Spec Pro spectroradiometer. Surface snow samples were analyzed to determine the concentration and size distribution of MD in each sample. An overflight of a four-rotor Unmanned Aerial Vehicle (UAV) equipped with an RGB digital camera sensor was carried out during the field operations. Finally, Landsat 8 Operational Land Imager (OLI) data covering the central European Alps were analyzed. Observed reflectance evidenced that MD strongly reduced the spectral reflectance of snow, in particular, from 350 to 600 nm. Reflectance was compared with that simulated by parameterizing the Snow, Ice, and Aerosol Radiation radiative transfer model. We defined a novel spectral index, the Snow Darkening Index (SDI), that combines different wavelengths showing nonlinear correlation with measured MD concentrations (R2 = 0.87, root-mean-square error = 0.037). We also estimated a positive instantaneous radiative forcing that reaches values up to 153 W/m2 for the most concentrated sampling area. SDI maps at local scale were produced using the UAV data, while regional SDI maps were generated with OLI data. These maps show the spatial distribution of MD in snow after a natural deposition from the Saharan desert. Such postdepositional experimental data are fundamental for validating radiative transfer models and global climate models that simulate the impact of MD on snow radiative properties.

  2. The He-3/He-4 ratios for solar energetic particle events during the Combined Release and Radiation Effects Satellite Mission

    NASA Technical Reports Server (NTRS)

    Chen, Jiasheng; Guzik, T. Gregory; Wefel, John P.

    1995-01-01

    Helium data measured by the University of Chicago instrument, ONR-604, are employed to determine the ratio of He-3 to He-4 for solar energetic particle (SEP) events over an energy range 50-110 MeV/nucleon during the 1990/1991 Combined Release and Radiation Effects Satellite mission. The Sun in this period is extremely active. A total of 29 separate SEP events have been identified; among them 16 major events have been analyzed to obtain He-3/He-4 ratios, with a mass resolution of 0.10 amu. Thirteen events have a He-3/He-4 ratio larger than 0.005, one order of magnitude greater than the solar coronal value. The He-3/He-4 ratio at energies of 50-110 MeV/nucleon is independent of the size of the SEP event, for the moderately large flares analyzed here. The helium energy spectra are represented by power laws. During the 1991 June flare period, different large-particle injections associated with different solar flares, but occurring from the same active region, have a similar average spectral index and a similar He-3/He-4 ratio. The spectral index of He-4 varies from event to event, i.e., from as small as 1.5 to as large as 7.5. A correlation is found between the inferred spectral index from gamma-ray measurements and our measured spectral indices for the 1991 June 11 and June 15 events, suggesting that the high-energy SEPs may come from the same acceleration event as the particles that interact at the Sun and produce the gamma rays. The implications of these results for particle acceleration and propagation at the flare site and in the solar corona are discussed.

  3. AN ACTIVE-PASSIVE COMBINED ALGORITHM FOR HIGH SPATIAL RESOLUTION RETRIEVAL OF SOIL MOISTURE FROM SATELLITE SENSORS (Invited)

    NASA Astrophysics Data System (ADS)

    Lakshmi, V.; Mladenova, I. E.; Narayan, U.

    2009-12-01

    Soil moisture is known to be an essential factor in controlling the partitioning of rainfall into surface runoff and infiltration and solar energy into latent and sensible heat fluxes. Remote sensing has long proven its capability to obtain soil moisture in near real-time. However, at the present time we have the Advanced Scanning Microwave Radiometer (AMSR-E) on board NASA’s AQUA platform is the only satellite sensor that supplies a soil moisture product. AMSR-E coarse spatial resolution (~ 50 km at 6.9 GHz) strongly limits its applicability for small scale studies. A very promising technique for spatial disaggregation by combining radar and radiometer observations has been demonstrated by the authors using a methodology is based on the assumption that any change in measured brightness temperature and backscatter from one to the next time step is due primarily to change in soil wetness. The approach uses radiometric estimates of soil moisture at a lower resolution to compute the sensitivity of radar to soil moisture at the lower resolution. This estimate of sensitivity is then disaggregated using vegetation water content, vegetation type and soil texture information, which are the variables on which determine the radar sensitivity to soil moisture and are generally available at a scale of radar observation. This change detection algorithm is applied to several locations. We have used aircraft observed active and passive data over Walnut Creek watershed in Central Iowa in 2002; the Little Washita Watershed in Oklahoma in 2003 and the Murrumbidgee Catchment in southeastern Australia for 2006. All of these locations have different soils and land cover conditions which leads to a rigorous test of the disaggregation algorithm. Furthermore, we compare the derived high spatial resolution soil moisture to in-situ sampling and ground observation networks

  4. Combined Aircraft and Satellite-Derived Storm Electric Current and Lightning Rates Measurements and Implications for the Global Electric Circuit

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.

    2010-01-01

    Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of electrified shower clouds and thunderstorms spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, with and without lightning, and with positive and negative fields above the storms. The measurements were made with the NASA ER-2 and the Altus-II high altitude aircrafts. Peak electric fields, with lightning transients removed, ranged from -1.0 kV/m to 16 kV/m, with a mean value of 0.9 kV/m. The median peak field was 0.29 kV/m. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean storms with lightning is 1.6 A while the mean current for land storms with lightning is 1.0 A. The mean current for oceanic storms without lightning (i.e., electrified shower clouds) is 0.39 A and the mean current for land storms without lightning is 0.13 A. Thus, on average, land storms with or without lightning have about half the mean current as their corresponding oceanic storm counterparts. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal lightning statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie

  5. Non-linear oscillation of inter-connected satellites system under the combined influence of the solar radiation pressure and dissipative force of general nature

    NASA Astrophysics Data System (ADS)

    Sharma, S.; Narayan, A.

    2001-06-01

    The non-linear oscillation of inter-connected satellites system about its equilibrium position in the neighabourhood of main resonance ??=3D 1, under the combined effects of the solar radiation pressure and the dissipative forces of general nature has been discussed. It is found that the oscillation of the system gets disturbed when the frequency of the natural oscillation approaches the resonance frequency.

  6. Subjective evaluation of the combined influence of satellite temperature sounding data and increased model resolution on numerical weather forecasting

    NASA Technical Reports Server (NTRS)

    Atlas, R.; Halem, M.; Ghil, M.

    1979-01-01

    The present evaluation is concerned with (1) the significance of prognostic differences resulting from the inclusion of satellite-derived temperature soundings, (2) how specific differences between the SAT and NOSAT prognoses evolve, and (3) comparison of two experiments using the Goddard Laboratory for Atmospheric Sciences general circulation model. The subjective evaluation indicates that the beneficial impact of sounding data is enhanced with increased resolution. It is suggested that satellite sounding data posses valuable information content which at times can correct gross analysis errors in data sparse regions.

  7. Combining New Satellite Tools and Models to Examine Role of Mesoscale Interactions in Formation and Intensification of Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Simpson, Joanne; Pierce, H.; Ritchie, L.; Liu, T.; Brueske, K.; Velden, C.; Halverson, J.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The objective of this research is to start filling the mesoscale gap to improve understanding and probability forecasts of formation and intensity variations of tropical cyclones. Sampling by aircraft equipped to measure mesoscale processes is expensive, thus confined in place and time. Hence we turn to satellite products. This paper reports preliminary results of a tropical cyclone genesis and early intensification study. We explore the role of mesoscale processes using a combination of products from TRMM, QuikSCAT, AMSU, also SSM/I, geosynchronous and model output. Major emphasis is on the role of merging mesoscale vortices. These initially form in midlevel stratiform cloud. When they form in regions of lowered Rossby radius of deformation (strong background vorticity) the mesoscale vortices can last long enough to interact and merge, with the weaker vortex losing vorticity to the stronger, which can then extend down to the surface. In an earlier cyclongenesis case (Oliver 1993) off Australia, intense deep convection occurred when the stronger vortex reached the surface; this vortex became the storm center while the weaker vortex was sheared out as the major rainband. In our study of Atlantic tropical cyclones originating from African waves, we use QuikSCAT to examine surface winds in the African monsoon trough and in the vortices which move westward off the coast, which may or may not undergo genesis (defined by NHC as reaching TD, or tropical depression, with a west wind to the south of the surface low). We use AMSU mainly to examine development of warm cores. TRMM passive microwave TMI is used with SSM/I to look at the rain structure, which often indicates eye formation, and to look at the ice scattering signatures of deep convection. The TRMM precipitation radar, PR, when available, gives precipitation cross sections. So far we have detailed studies of two African-origin cyclones, one which became severe hurricane Floyd 1999, and the other reached TD2 in June

  8. Combining a two-sourcepatch model with satellite data to monitor daily evapotranspiration at a regional scale

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this work, we present a micro-meteorological approach for estimating surface energy fluxes that can be operationally used together with satellite images to monitor surface energy fluxes at a regional scale. In particular we will focus on the retrieval of daily evapotranspiration. The feasibility ...

  9. Retrieval of atmospheric-temperature and water-vapor profiles by use of combined satellite and ground-based infrared spectral-radiance measurements.

    PubMed

    Ho, Shu-Peng; Smith, William L; Huang, Hung-Lung

    2002-07-10

    A nonlinear sounding retrieval algorithm is used to produce vertical-temperature and water-vapor profiles from coincident observations taken by the airborne High-resolution Interferometer Sounder (HIS) and the ground-based Atmospheric Emitted Radiance Interferometer (AERI) during the SUbsonic Contrails and Clouds Effects Special Study (SUCCESS). Also, clear sky Geostationary Operational Environmental Satellite (GOES) and AERI radiance measurements, achieved on a daily real-time basis at the Department of Energy's Oklahoma CART (Cloud and Radiation Testbed) site, are used to demonstrate the current profiling capability by use of simultaneous geostationary satellite and ground-based remote sensing observations under clear-sky conditions. The discrepancy principle, a method to find the proper smoothing parameters from the minimum value between the normalized spectral residual norm and the a priori upper bound, is used to demonstrate the feasibility and effectiveness of on-line simultaneous tuning of the multiple weighting and smoothing parameters from the combined satellite/airborne and ground-based measurements for the temperature and water-vapor retrieval in this nonlinear-retrieval process. An objective method to determine the degrees of freedom (d.f.) of the observation signal is derived. The d.f. of the radiance signal for the combined GOES and AERI measurements is larger than that for either instrument alone; while the d.f. of the observation signal for the combined GOES and AERI measurements is larger than that for either instrument alone and of the combined GOES and AERI measurements. The use of simultaneous clear-sky AERI and GOES data now provides improved vertical temperature and moisture soundings on an hourly basis for use in the Atmospheric Radiation Measurement program [J. Appl. Meteorol. 37, 875 (1998)]. PMID:12141504

  10. Analysis of tropical-like cyclones over the Mediterranean Sea through a combined modeling and satellite approach

    NASA Astrophysics Data System (ADS)

    Miglietta, M. M.; Laviola, S.; Malvaldi, A.; Conte, D.; Levizzani, V.; Price, C.

    2013-05-01

    Several Mediterranean vortices with characteristics similar to tropical cyclones are analyzed by means of numerical simulations, satellite products and lightning data. Numerical analysis suggests that the broad tropical-like cyclone category includes in reality a set of different cyclones, ranging from very small and weak vortices to larger and stronger cyclones. One case displays a much longer persistence of tropical features than the other events. The analysis of the tracks identifies two preferred areas of occurrence: the Ionian sea and the Balearic Islands. The satellite analysis of cloud top height and retrieved rainfall indicates that the stage characterized by the most intense convective activity and rainfall anticipates the mature phase, when the cyclone is more intense and characterized by tropical features, during which convection is shallower and rainfall weaker. This result is confirmed by a preliminary analysis of the lightning activity.

  11. Dust aerosol characterization and transport features based on combined ground-based, satellite and model-simulated data

    NASA Astrophysics Data System (ADS)

    Vijayakumar, K.; Devara, P. C. S.; Rao, S. Vijaya Bhaskara; Jayasankar, C. K.

    2016-06-01

    In this paper, we study aerosol characteristics over an urban station in Western India, during a dust event that occurred between 19 and 26 March 2012, with the help of ground-based and satellite measurements and model simulation data. The aerosol parameters are found to change significantly during dust events and they suggest dominance of coarse mode aerosols. The fine mode fraction, size distribution and single scattering albedo reveal that dust (natural) aerosols dominate the anthropogenic aerosols over the study region. Ground-based measurements show drastic reduction in visibility on the dust-laden day (22 March 2012). Additionally, HYSPLIT model and satellite daily data have been used to trace the source, path and spatial extent of dust storm events. Most of the dust aerosols, during the study period, travel from west-to-east pathway from source-to-sink region. Furthermore, aerosol vertical profiles from CALIPSO and synoptic meteorological parameters from ECMWF re-analysis data reveal a layer of thick dust extending from surface to an altitude of about 4 km, and decrease in temperature and increase in specific humidity, respectively. The aerosol radiative forcing calculations indicate more cooling at the surface and warming in the atmosphere during dust event. The results of satellite observations are found to have good consistency with ground-based air quality measurements. Synthesis of satellite data integrated with ground-based observations, supplemented by model analysis, is found to be a promising technique for improved understanding of dust storm phenomenon and its impact on regional climate.

  12. Push-Broom-Type Very High-Resolution Satellite Sensor Data Correction Using Combined Wavelet-Fourier and Multiscale Non-Local Means Filtering

    PubMed Central

    Kang, Wonseok; Yu, Soohwan; Seo, Doochun; Jeong, Jaeheon; Paik, Joonki

    2015-01-01

    In very high-resolution (VHR) push-broom-type satellite sensor data, both destriping and denoising methods have become chronic problems and attracted major research advances in the remote sensing fields. Since the estimation of the original image from a noisy input is an ill-posed problem, a simple noise removal algorithm cannot preserve the radiometric integrity of satellite data. To solve these problems, we present a novel method to correct VHR data acquired by a push-broom-type sensor by combining wavelet-Fourier and multiscale non-local means (NLM) filters. After the wavelet-Fourier filter separates the stripe noise from the mixed noise in the wavelet low- and selected high-frequency sub-bands, random noise is removed using the multiscale NLM filter in both low- and high-frequency sub-bands without loss of image detail. The performance of the proposed method is compared to various existing methods on a set of push-broom-type sensor data acquired by Korean Multi-Purpose Satellite 3 (KOMPSAT-3) with severe stripe and random noise, and the results of the proposed method show significantly improved enhancement results over existing state-of-the-art methods in terms of both qualitative and quantitative assessments. PMID:26378532

  13. Combining satellite observations to develop a daily global soil moisture product for a wide range of applications

    NASA Astrophysics Data System (ADS)

    Enenkel, M.; Reimer, C.; Dorigo, W.; Wagner, W.; Pfeil, I.; Parinussa, R.; De Jeu, R.

    2015-11-01

    The soil moisture dataset that is generated via the Climate Change Initiative (CCI) of the European Space Agency (ESA) (ESA CCI SM) is a popular research product. It is composed of observations from nine different satellites and aims to exploit the individual strengths of active (radar) and passive (radiometer) sensors, thereby providing surface soil moisture estimates at a spatial resolution of 0.25°. However, the annual updating cycle limits the use of the ESA CCI SM dataset for operational applications. Therefore, this study proposes an adaptation of the ESA CCI processing chain for daily global updates via satellite-derived near real-time (NRT) soil moisture observations. In order to extend the ESA CCI SM dataset from 1978 to present we use NRT observations from the Advanced SCATterometer on-board the MetOp satellites and the Advanced Microwave Scanning Radiometer 2 on-board GCOM-W. Since these NRT observations do not incorporate the latest algorithmic updates, parameter databases, and intercalibration efforts, by nature they offer a lower quality than reprocessed offline datasets. Our findings indicate that, despite issues in arid regions, the new "CCI NRT" dataset shows a good correlation with ESA CCI SM. The average global correlation coefficient between CCI NRT and ESA CCI SM (Pearson's R) is 0.8. An initial validation with 40 in-situ observations in France, Kenya, Senegal and Kenya yields an average R of 0.58 and 0.49 for ESA CCI SM and CCI NRT respectively. In summary, the CCI NRT dataset is getting ready for operational use, supporting applications such as drought and flood monitoring, weather forecasting or agricultural applications.

  14. Evaluation and development of satellite inferences of convective storm intensity using combined case study analysis and thunderstorm model simulations

    NASA Technical Reports Server (NTRS)

    Cotton, W. R.; Tripoli, G. J.

    1980-01-01

    Major research accomplishments which were achieved during the first year of the grant are summarized. The research concentrated in the following areas: (1) an examination of observational requirements for predicting convective storm development and intensity as suggested by recent numerical experiments; (2) interpretation of recent 3D numerical experiments with regard to the relationship between overshooting tops and surface wind gusts; (3) the development of software for emulating satellite-inferred cloud properties using 3D cloud model predicted data; and (4) the development of a conceptual/semi-quantitative model of eastward propagating, mesoscale convective complexes forming to the lee of the Rocky Mountains.

  15. Evaluation and development of satellite inferences of convective storm intensity using combined case study and thunderstorm model simulations

    NASA Technical Reports Server (NTRS)

    Cotton, W. R.; Tripoli, G. J.

    1982-01-01

    Observational requirements for predicting convective storm development and intensity as suggested by recent numerical experiments are examined. Recent 3D numerical experiments are interpreted with regard to the relationship between overshooting tops and surface wind gusts. The development of software for emulating satellite inferred cloud properties using 3D cloud model predicted data and the simulation of Heymsfield (1981) Northern Illinois storm are described as well as the development of a conceptual/semi-quantitative model of eastward propagating, mesoscale convective complexes forming to the lee of the Rocky Mountains.

  16. Combining New Satellite Tools and Models to Examine Role of Mesoscale Interactions in Formation and Intensification of Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Simpson, Joanne; Pierce, H.; Ritchie, L.; Liu, T.; Brueske, K.; Velden, C.; Halverson, J.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The objective of this research is to start filling the mesoscale gap to improve understanding and probability forecasts of formation and intensity variations of tropical cyclones. Sampling by aircraft equipped to measure mesoscale processes is expensive, thus confined in place and time. Hence we turn to satellite products. This paper reports preliminary results of a tropical cyclone genesis and early intensification study. We explore the role of mesoscale processes using a combination of products from TRMM, QuikSCAT, AMSU, also SSM/I, geosynchronous and model output. Major emphasis is on the role of merging mesoscale vortices. These initially form in midlevel stratiform cloud. When they form in regions of lowered Rossby radius of deformation (strong background vorticity) the mesoscale vortices can last long enough to interact and merge, with the weaker vortex losing vorticity to the stronger, which can then extend down to the surface. In an earlier cyclongenesis case (Oliver 1993) off Australia, intense deep convection occurred when the stronger vortex reached the surface; this vortex became the storm center while the weaker vortex was sheared out as the major rainband. In our study of Atlantic tropical cyclones originating from African waves, we use QuikSCAT to examine surface winds in the African monsoon trough and in the vortices which move westward off the coast, which may or may not undergo genesis (defined by NHC as reaching TD, or tropical depression, with a west wind to the south of the surface low). We use AMSU mainly to examine development of warm cores. TRMM passive microwave TMI is used with SSM/I to look at the rain structure, which often indicates eye formation, and to look at the ice scattering signatures of deep convection. The TRMM precipitation radar, PR, when available, gives precipitation cross sections. So far we have detailed studies of two African-origin cyclones, one which became severe hurricane Floyd 1999, and the other reached TD2 in June

  17. Constraining dark matter models from a combined analysis of Milky Way satellites with the Fermi Large Area Telescope.

    PubMed

    Ackermann, M; Ajello, M; Albert, A; Atwood, W B; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Burnett, T H; Buson, S; Caliandro, G A; Cameron, R A; Cañadas, B; Caraveo, P A; Casandjian, J M; Cecchi, C; Charles, E; Chekhtman, A; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cutini, S; de Angelis, A; de Palma, F; Dermer, C D; Digel, S W; do Couto e Silva, E; Drell, P S; Drlica-Wagner, A; Falletti, L; Favuzzi, C; Fegan, S J; Ferrara, E C; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Guiriec, S; Gustafsson, M; Hadasch, D; Hayashida, M; Hays, E; Hughes, R E; Jeltema, T E; Jóhannesson, G; Johnson, R P; Johnson, A S; Kamae, T; Katagiri, H; Kataoka, J; Knödlseder, J; Kuss, M; Lande, J; Latronico, L; Lionetto, A M; Llena Garde, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Naumann-Godo, M; Norris, J P; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Parent, D; Pesce-Rollins, M; Pierbattista, M; Piron, F; Pivato, G; Porter, T A; Profumo, S; Rainò, S; Razzano, M; Reimer, A; Reimer, O; Ritz, S; Roth, M; Sadrozinski, H F-W; Sbarra, C; Scargle, J D; Schalk, T L; Sgrò, C; Siskind, E J; Spandre, G; Spinelli, P; Strigari, L; Suson, D J; Tajima, H; Takahashi, H; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Tibaldo, L; Tinivella, M; Torres, D F; Troja, E; Uchiyama, Y; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Wang, P; Winer, B L; Wood, K S; Wood, M; Yang, Z; Zimmer, S; Kaplinghat, M; Martinez, G D

    2011-12-01

    Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10(-26)  cm3  s(-1) at 5 GeV to about 5×10(-23)   cm3  s(-1) at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section (∼3×10(-26)  cm3  s(-1) for a purely s-wave cross section), without assuming additional boost factors. PMID:22242987

  18. Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Albert, A.; Atwood, W. B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bladford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Ferrara, E. C.; Gehrels, N.; Hays, E.; Scargle, J. D.; Thompson, D. J.; Troja, E.

    2011-01-01

    Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10(exp -26) cm(exp 3) / s at 5 GeV to about 5 X 10(exp -23) cm(exp 3)/ s at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section (approx 3 X 10(exp -26) cm(exp 3)/s for a purely s-wave cross section), without assuming additional boost factors.

  19. Influence of static magnetic fields combined with human insulin-like growth factor 1 on human satellite cell cultures.

    PubMed

    Birk, Richard; Sommer, J Ulrich; Haas, Dominik; Faber, Anne; Aderhold, Christoph; Schultz, Johannes D; Hoermann, Karl; Stern-Straeter, Jens

    2014-01-01

    Tissue engineering represents a promising research field, targeting the creation of new functional muscle tissue in vitro. The aim of the present study was to show the influence of static magnetic fields (SMF) and insulin-like growth factor-1 (IGF1), as enhancing stimuli on human satellite cell cultures, which are preferred sources of stem cells in engineering skeletal muscle tissue. To detect effects on myogenic maturation and proliferation, AlamarBlue® proliferation, assay and semi-quantitative reverse transcription-polymerase chain reaction of following markers was performed: desmin (DES), myogenic factor-5 (MYF5), myogenic differentiation antigen-1 (MYOD1), myogenin (MYOG), myosin heavy chain (MYH) and α1 actin (ACTA1). As a distinct marker of differentiation, immunohistochemical staining and fusion index determination was performed on satellite cell cultures stimulated with IGF1 and IGF1-plus-SMF with an intensity of 80 mT. Proliferation was increased by additional SMF application to IGF1-stimulated cell cultures on the first day of myogenesis. Relative gene expression of measured markers was increased by IGF1 application in the first days of myogenesis except for ACTA1. Additional SMF application enhanced this effect. Nevertheless we were unable to demonstrate the formation of contractile muscle tissue. Immunhistochemical staining verified muscle origin and all markers were displayed. PMID:25189891

  20. Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope

    SciTech Connect

    Ackermann, M.; Ajello, M.; Albert, A.; Atwood, W.B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R.D.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Burnett, T.H.; Buson, S.; /more authors..

    2012-09-14

    Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10{sup -26} cm{sup 3} s{sup -1} at 5 GeV to about 5 x 10{sup -23} cm{sup 3} s{sup -1} at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section ({approx}3 x 10{sup -26} cm{sup 3} s{sup -1} for a purely s-wave cross section), without assuming additional boost factors.

  1. Limits to dark matter annihilation cross-section from a combined analysis of MAGIC and Fermi-LAT observations of dwarf satellite galaxies

    DOE PAGESBeta

    Ahnen, M. L.

    2016-02-16

    Here, we present the first joint analysis of gamma-ray data from the MAGIC Cherenkov telescopes and the Fermi Large Area Telescope (LAT) to search for gamma-ray signals from dark matter annihilation in dwarf satellite galaxies. We combine 158 hours of Segue 1 observations with MAGIC with 6-year observations of 15 dwarf satellite galaxies by the Fermi-LAT. We obtain limits on the annihilation cross-section for dark matter particle masses between 10 GeV and 100 TeV - the widest mass range ever explored by a single gamma-ray analysis. These limits improve on previously published Fermi-LAT and MAGIC results by up to amore » factor of two at certain masses. Our new inclusive analysis approach is completely generic and can be used to perform a global, sensitivity-optimized dark matter search by combining data from present and future gamma-ray and neutrino detectors.« less

  2. Methodology for evaluating lateral boundary conditions in the regional chemical transport model MATCH (v5.5.0) using combined satellite and ground-based observations

    NASA Astrophysics Data System (ADS)

    Andersson, E.; Kahnert, M.; Devasthale, A.

    2015-11-01

    Hemispheric transport of air pollutants can have a significant impact on regional air quality, as well as on the effect of air pollutants on regional climate. An accurate representation of hemispheric transport in regional chemical transport models (CTMs) depends on the specification of the lateral boundary conditions (LBCs). This study focuses on the methodology for evaluating LBCs of two moderately long-lived trace gases, carbon monoxide (CO) and ozone (O3), for the European model domain and over a 7-year period, 2006-2012. The method is based on combining the use of satellite observations at the lateral boundary with the use of both satellite and in situ ground observations within the model domain. The LBCs are generated by the global European Monitoring and Evaluation Programme Meteorological Synthesizing Centre - West (EMEP MSC-W) model; they are evaluated at the lateral boundaries by comparison with satellite observations of the Terra-MOPITT (Measurements Of Pollution In The Troposphere) sensor (CO) and the Aura-OMI (Ozone Monitoring Instrument) sensor (O3). The LBCs from the global model lie well within the satellite uncertainties for both CO and O3. The biases increase below 700 hPa for both species. However, the satellite retrievals below this height are strongly influenced by the a priori data; hence, they are less reliable than at, e.g. 500 hPa. CO is, on average, underestimated by the global model, while O3 tends to be overestimated during winter, and underestimated during summer. A regional CTM is run with (a) the validated monthly climatological LBCs from the global model; (b) dynamical LBCs from the global model; and (c) constant LBCs based on in situ ground observations near the domain boundary. The results are validated against independent satellite retrievals from the Aqua-AIRS (Atmospheric InfraRed Sounder) sensor at 500 hPa, and against in situ ground observations from the Global Atmospheric Watch (GAW) network. It is found that (i) the use of

  3. Combined Use of Satellite Observations with Urban Surface Characteristics to Estimate PM Concentrations by Employing Mixed-Effects Models

    NASA Astrophysics Data System (ADS)

    Beloconi, Anton; Benas, Nikolaos; Chrysoulakis, Nektarios; Kamarianakis, Yiannis

    2015-06-01

    Linear mixed effects models were developed for the estimation of the average daily Particulate Matter (PM) concentration spatial distribution over the area of Greater London (UK). Both fine (PM2.5) and coarse (PM10) concentrations were predicted for the 2002-2012 time period, based on satellite data. The latter included Aerosol Optical Thickness (AOT) at 3.3 km spatial resolution, as well as the Surface Relative Humidity, Surface Temperature and K-Index derived from MODIS (Moderate Resolution Imaging Spectroradiometer) sensor. For a meaningful interpretation of the association among these variables, all data were homogenized with regard to spatial support and geographic projection, thus addressing the change of support problem and leading to a valid statistical inference. To this end, spatial (2D) and spatio-temporal (3D) kriging techniques were applied to in-situ particulate matter concentrations and the leave-one-station-out cross-validation was performed on a daily level to gauge the quality of the predictions. Satellite-derived covariates displayed clear seasonal patterns; in order to work with data which is stationary in mean, for each covariate, deviations from its estimated annual profiles were computed using nonlinear least squares and nonlinear absolute deviations. High-resolution land-cover and morphology static datasets were additionally incorporated in the analysis in order to catch the effects of nearby emission sources and sequestration sites. For pairwise comparisons of the particulate matter concentration means at distinct land-cover classes, the pairwise comparisons method for unequal sample sizes, known as Tukey’s method, was performed. The use of satellite-derived products allowed better assessment of space-time interactions of PM, since these daily spatial measurements were able to capture differences in PM concentrations between grid cells, while the use of high-resolution land-cover and morphology static datasets allowed accounting for local

  4. Determination of Large-Scale Cloud Ice Water Concentration by Combining Surface Radar and Satellite Data in Support of ARM SCM Activities

    SciTech Connect

    Liu, Guosheng

    2013-03-15

    Single-column modeling (SCM) is one of the key elements of Atmospheric Radiation Measurement (ARM) research initiatives for the development and testing of various physical parameterizations to be used in general circulation models (GCMs). The data required for use with an SCM include observed vertical profiles of temperature, water vapor, and condensed water, as well as the large-scale vertical motion and tendencies of temperature, water vapor, and condensed water due to horizontal advection. Surface-based measurements operated at ARM sites and upper-air sounding networks supply most of the required variables for model inputs, but do not provide the horizontal advection term of condensed water. Since surface cloud radar and microwave radiometer observations at ARM sites are single-point measurements, they can provide the amount of condensed water at the location of observation sites, but not a horizontal distribution of condensed water contents. Consequently, observational data for the large-scale advection tendencies of condensed water have not been available to the ARM cloud modeling community based on surface observations alone. This lack of advection data of water condensate could cause large uncertainties in SCM simulations. Additionally, to evaluate GCMs cloud physical parameterization, we need to compare GCM results with observed cloud water amounts over a scale that is large enough to be comparable to what a GCM grid represents. To this end, the point-measurements at ARM surface sites are again not adequate. Therefore, cloud water observations over a large area are needed. The main goal of this project is to retrieve ice water contents over an area of 10 x 10 deg. surrounding the ARM sites by combining surface and satellite observations. Built on the progress made during previous ARM research, we have conducted the retrievals of 3-dimensional ice water content by combining surface radar/radiometer and satellite measurements, and have produced 3-D cloud ice

  5. Satellite broadcasting in Europe

    NASA Astrophysics Data System (ADS)

    Bartholome, P.

    1984-05-01

    Three main communications services are recognized by the International Telecommunications Union: the Fixed Service, the Mobile Service and the Broadcasting Service. In Europe, EUTELSAT has just begun to exploit the first ECS satellite. The ESA-launched satellite was originally designed to provide an international public telecommunication service, however, the satellite will be used now almost exclusively for TV program distribution, while a second ECS satellite will be used for telephony. Despite plans for the launch of a third, countries in Europe are looking to other organizations such as INTELSAT for greater satellite capacity. Other organizations include Unisat, DFS/Copernicus, GDL, and Videosat. Both satellite and cable networks will increase the program-viewing audience, thus encouraging plans for a pan-European television service intended for an international audience. Although the combination of cable networks and distribution satellites looks promising, high-power broadcasting satellites will play an important role because of flexibility and additional program distribution.

  6. Supraglacial Streams on the Greenland Ice Sheet Delineated from Combined Spectral-Shape Information in High Resolution Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Yang, K.; Smith, L. C.

    2012-12-01

    Supraglacial meltwater streams and lakes that form each summer across large expanses of the Greenland Ice Sheet (GrIS) ablation zone have global implications for sea level rise yet remain one of the least-studied hydrologic systems on Earth. Remote sensing of supraglacial streams is challenging owing to their narrow width (~1 - 30 m), and proximity to other features having similar visible/NIR reflectance (lakes and slush) or shape (dry stream channels, crevasses, and fractures). This presentation presents a new, automated "spectral-shape" procedure for delineating actively flowing streams in high-resolution satellite imagery, utilizing both spectral and pattern information. First, a modified Normalized Difference Water Index adapted for ice (NDWIice) enhances the spectral contrast between open water and drier snow/ice surfaces. Next, three NDWIice thresholds are used to mask deep-water lakes and discern open water from slush, in concert with a multi-points fast marching method to rejoin resulting stream fragments. Comparison of this procedure with manual digitization for six WorldView-2 images in southwestern Greenland demonstrates its value for detecting actively flowing supraglacial streams, especially in slushy areas where classification performance improves dramatically versus simple threshold methods. While a simple threshold approach is satisfactory for areas known to be slush-free, the procedure outlined here enables comprehensive stream mapping across the GrIS ablation zone, regardless of slush conditions and/or the presence of similarly shaped glaciological features.

  7. Interactive access to LP DAAC satellite data archives through a combination of open-source and custom middleware web services

    USGS Publications Warehouse

    Davis, Brian N.; Werpy, Jason; Friesz, Aaron M.; Impecoven, Kevin; Quenzer, Robert; Maiersperger, Tom; Meyer, David J.

    2015-01-01

    Current methods of searching for and retrieving data from satellite land remote sensing archives do not allow for interactive information extraction. Instead, Earth science data users are required to download files over low-bandwidth networks to local workstations and process data before science questions can be addressed. New methods of extracting information from data archives need to become more interactive to meet user demands for deriving increasingly complex information from rapidly expanding archives. Moving the tools required for processing data to computer systems of data providers, and away from systems of the data consumer, can improve turnaround times for data processing workflows. The implementation of middleware services was used to provide interactive access to archive data. The goal of this middleware services development is to enable Earth science data users to access remote sensing archives for immediate answers to science questions instead of links to large volumes of data to download and process. Exposing data and metadata to web-based services enables machine-driven queries and data interaction. Also, product quality information can be integrated to enable additional filtering and sub-setting. Only the reduced content required to complete an analysis is then transferred to the user.

  8. Retrieval of Surface and Atmospheric Geophysical Variables over Snow-Covered Land from Combined Microwave and Infrared Satellite Observations.

    NASA Astrophysics Data System (ADS)

    Prigent, C.; Aires, F.; Rossow, W. B.

    2003-03-01

    Surface temperature and emissivities, as well as atmospheric water vapor and cloud liquid water, have been calculated from Special Sensor Microwave Imager observations for snow-covered land areas using a neural network inversion scheme that includes first-guess information. A learning database to train the neural network is derived from a global collection of coincident surface and atmospheric parameters, extracted from the National Centers for Environmental Prediction reanalysis, from the International Satellite Cloud Climatology Project data, and from microwave emissivity atlases previously calculated. Despite the large space and time variability of the snow microwave response, the surface and atmospheric parameters are retrieved. Water vapor is estimated with a theoretical rms error of approximately 30%, verified against radiosonde measurements, that is almost the same as over snow-free land. The theoretical rms error of the surface skin temperature retrieval is 1.5 and 1.9 K, respectively, for clear and cloudy scenes. The surface skin temperatures are compared with the surface air temperatures measured at meteorological stations to verify that the expected differences are found. The space and time variations of the retrieved surface emissivities are evaluated by comparison with surface parameter variations such as surface air temperature, snow depth, and vegetation cover.

  9. Land surface skin temperatures from a combined analysis of microwave and infrared satellite observations for an all-weather evaluation of the differences between air and skin temperatures

    NASA Astrophysics Data System (ADS)

    Prigent, Catherine; Aires, Filipe; Rossow, William B.

    2003-05-01

    A neural network inversion scheme including first guess information has been developed to retrieve surface temperature Ts, along with atmospheric water vapor, cloud liquid water, and surface emissivities over land from a combined analysis of Special Sensor Microwave/Imager (SSM/I) and International Satellite Cloud Climatology Project (ISCCP) data. In the absence of routine in situ surface skin measurements, retrieved Ts values are evaluated by comparison to the surface air temperature Tair measured by the meteorological station network. The Ts - Tair difference shows all the expected variations with solar flux, soil characteristics, and cloudiness. During daytime the Ts - Tair difference is driven by the solar insulation, with positive differences that increase with increasing solar flux. With decreasing soil and vegetation moisture the evaporation rate decreases, increasing the sensible heat flux, thus requiring larger Ts - Tair differences. Nighttime Ts - Tair differences are governed by the longwave radiation balance, with Ts usually closer or lower than Tair. The presence of clouds dampens all the difference. After suppression of the variability associated to the diurnal solar flux variations, the Ts and Tair data sets show very good agreement in their synoptic variations, even for cloudy cases, with no bias and a global rms difference of ˜2.9 K. This value is an upper limit of the retrieval rms because it includes errors in the in situ data as well as errors related to imperfect time and space collocations between the satellite and in situ measurements.

  10. Development of a concatenated Reed-Solomon/Viterbi FEC combined modem and its field test via 14/11 GHz satellite

    NASA Astrophysics Data System (ADS)

    Fujino, T.; Moritani, Y.; Miyake, M.; Murakami, K.; Shibuya, A.

    The development of a concatenated FEC (forward error connecting) codec and its associating PSK (phase shift keying) modem aimed at low-bit-rate satellite communications use are discussed, and their performance in a field test at the 14-GHz/11-GHz band using an INTELSAT-V satellite is assessed. The FEC codec consists of a convolutional encoder with a Viterbi decoder for inner coding and a Reed-Solomon encoder with a Euclid decoder for outer coding. A coding gain of 7.5 dB was achieved at a bit error rate (BER) of 10-6 relative to the uncoded performance, and virtually error-free transmission was achieved at a carrier/noise (C/N) ratio of 0 dB. Some tests were conducted to transmit a voice signal and G3- and G4-facsimile signals, which revealed that the qualities of both received facsimile signals were highly dependent on the event error probabilities rather than the BERs. It is concluded that the developed FEC combined modem is useful for reliable data transmission in the low C/N ratio environment.

  11. Towards stochastically downscaled precipitation in the Tropics based on a robust 1DD combined satellite product and a high resolution IR-based rain mask

    NASA Astrophysics Data System (ADS)

    Guilloteau, Clement; Roca, Rémy; Gosset, Marielle

    2015-04-01

    In the Tropics where the ground-based rain gauges network is very sparse, satellite rainfall estimates are becoming a compulsory source of information for various applications: hydrological modeling, water resources management or vegetation-monitoring. The tropical Tropical Amount of Precipitation with Estimate of Error (TAPEER) algorithm, developed within the framework of Megha-Tropiques satellite mission is a robust estimate of surface rainfall accumulations at the daily, one degree resolution. TAPEER validation in West Africa has proven its accuracy. Nevertheless applications that involve non-linear processes (such as surface runoff) require finer space / time resolution than one degree one day, or at least the statistical characterization of the sub-grid rainfall variability. TAPEER is based on a Universally Adjusted Global Precipitation Index (UAGPI) technique. The one degree, one day estimation relies on the combination of observations from microwave radiometers embarked on the 7 platforms forming the GPM constellation of low earth orbit satellites together with geostationary infra-red (GEO-IR) imagery. TAPEER provides as an intermediate product a high-resolution rain-mask based on the GEO-IR information (2.8 km, 15 min in Africa). The main question of this work is, how to use this high-resolution mask information as a constraint for downscaling ? This work first presents the multi-scale evaluation of TAPEER's rain detection mask against ground X-band polarimetric radar data and TRMM precipitation radar data in West Africa, through wavelet transform. Other algorithms (climate prediction center morphing technique CMORPH, global satellite mapping of precipitation GSMaP, multi-sensor precipitation estimate MPE) detection capabilities are also evaluated. Spatio-temporal wavelet filtering of the detection mask is then used to compute precipitation probability at the GEO-IR resolution. The wavelet tool is finally used to stochastically generate rain / no rain field

  12. Combining Satellite Data and Models to Assess the Impacts of Urbanization on the Continental US Surface Climate

    NASA Technical Reports Server (NTRS)

    Bounoua, L.; Zhang, P.; Imhoff, M.; Santanello, J.; Kumar, S.; Shepherd, M.; Quattrochi, D.; Silva, J.; Rosenzweigh, C.; Gaffin, S.; Mostovoy, G.

    2013-01-01

    Urbanization is one of the most important and long lasting forms of land transformation. Urbanization affects the surface climate in different ways: (1) by reduction of the vegetation fraction causing subsequent reduction in photosynthesis and plant s water transpiration, (2) by alternation of surface runoff and infiltration and their impacts on soil moisture and the water table, (3) by change in the surface albedo and surface energy partitioning, and (4) by transformation of the surface roughness length and modification of surface fluxes. Land cover and land use change maps including urban areas have been developed and will be used in a suite of land surface models of different complexity to assess the impacts of urbanization on the continental US surface climate. These maps and datasets based on a full range of available satellite data and ground observations will be used to characterize distant-past (pre-urban), recent-past (2001), present (2010), and near future (2020) land cover and land use changes. The main objective of the project is to assess the impacts of these land transformation on past, current and near-future climate and the potential feedbacks from these changes on the atmospheric, hydrologic, biological, and socio-economic properties beyond the immediate metropolitan regions of cities and their near suburbs. The WRF modeling system will be used to explore the nature and the magnitude of the two-way interactions between urban lands and the atmosphere and assess the overall regional dynamic effect of urban expansion on the northeastern US weather and climate

  13. Simulation of whistler waves excited in the presence of a cold plasma cloud - Implications for the CRRES mission. [Combined Release and Radiation Effects Satellite

    NASA Technical Reports Server (NTRS)

    Pritchett, P. L.; Schriver, D.; Ashour-Abdalla, M.

    1991-01-01

    A one-dimensional electromagnetic particle simulation model is constructed to study the excitation of whistler waves in the presence of a cold plasma cloud for conditions representative of those after the release of lithium in the inner plasma sheet during the Combined Release and Radiation Effect Satellite mission. The results indicate that a standing-wave pattern with discrete wave frequencies is formed within the cloud. The magnetic wave amplitude inside the cloud, which is limited by quasi-linear diffusion, is of the order of several nanoteslas. Assuming a magnetospheric loss cone of 5 deg, the observed pitch angle diffusion produced by the whistler waves is sufficient to put the electrons on strong diffusion.

  14. Calculating Freshwater Input from Iceberg Melt in Greenlandic Fjords by Combining In Situ Observations of Iceberg Movement with High Resolution Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Sulak, D. J.; Sutherland, D.; Stearns, L. A.; Hamilton, G. S.

    2015-12-01

    Understanding fjord circulation in Greenland's outlet glacial fjords is crucial to explaining recent temporal and spatial variability in glacier dynamics, as well as freshwater transport on the continental shelf. The fjords are commonly assumed to exhibit a plume driven circulation that draws in warmer and saltier Atlantic-origin water toward the glacier at depth. Freshwater input at glacier termini directly drives this circulation and significantly influences water column stratification, which indirectly feeds back on the plume driven circulation. Previous work has focused on freshwater inputs from surface runoff and submarine melting, but the contribution from iceberg melt, a potentially important freshwater source, has not been quantified. Here, we develop a new technique combining in situ observations of movement from iceberg-mounted GPS units with multispectral satellite imagery from Landsat 8. The combination of datasets allows us to examine the details of iceberg movement and quantify mean residence times in a given fjord. We then use common melt rate parameterizations to estimate freshwater input for a given iceberg, utilizing novel satellite-derived iceberg distributions to scale up to a fjord-wide freshwater contribution. We apply this technique to Rink Isbræ and Kangerlussuup Sermia in west Greenland, and Helheim Glacier in southeast Greenland. The analysis can be rapidly expanded to look at other systems as well as seasonal and interannual changes in how icebergs affect the circulation and stratification of Greenland's outlet glacial fjords. Ultimately, this work will lead to a more complete understanding of the wide range of factors that control the observed regional variability in Greenland's glaciers.

  15. Satellite Communication.

    ERIC Educational Resources Information Center

    Technology Teacher, 1985

    1985-01-01

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

  16. Combination of Genetic Algorithm and Dempster-Shafer Theory of Evidence for Land Cover Classification Using Integration of SAR and Optical Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Chu, H. T.; Ge, L.

    2012-07-01

    The integration of different kinds of remotely sensed data, in particular Synthetic Aperture Radar (SAR) and optical satellite imagery, is considered a promising approach for land cover classification because of the complimentary properties of each data source. However, the challenges are: how to fully exploit the capabilities of these multiple data sources, which combined datasets should be used and which data processing and classification techniques are most appropriate in order to achieve the best results. In this paper an approach, in which synergistic use of a feature selection (FS) methods with Genetic Algorithm (GA) and multiple classifiers combination based on Dempster-Shafer Theory of Evidence, is proposed and evaluated for classifying land cover features in New South Wales, Australia. Multi-date SAR data, including ALOS/PALSAR, ENVISAT/ASAR and optical (Landsat 5 TM+) images, were used for this study. Textural information were also derived and integrated with the original images. Various combined datasets were generated for classification. Three classifiers, namely Artificial Neural Network (ANN), Support Vector Machines (SVMs) and Self-Organizing Map (SOM) were employed. Firstly, feature selection using GA was applied for each classifier and dataset to determine the optimal input features and parameters. Then the results of three classifiers on particular datasets were combined using the Dempster-Shafer theory of Evidence. Results of this study demonstrate the advantages of the proposed method for land cover mapping using complex datasets. It is revealed that the use of GA in conjunction with the Dempster-Shafer Theory of Evidence can significantly improve the classification accuracy. Furthermore, integration of SAR and optical data often outperform single-type datasets.

  17. Towards high temporal and moderate spatial resolutions in the remote sensing retrieval of evapotranspiration by combining geostationary and polar orbit satellite data

    NASA Astrophysics Data System (ADS)

    Barrios, José Miguel; Ghilain, Nicolas; Arboleda, Alirio; Gellens-Meulenberghs, Françoise

    2014-05-01

    Evapotranspiration (ET) is the water flux going from the surface into the atmosphere as result of soil and surface water evaporation and plant transpiration. It constitutes a key component of the water cycle and its quantification is of crucial importance for a number of applications like water management, climatic modelling, agriculture monitoring and planning, etc. Estimating ET is not an easy task; specially if large areas are envisaged and various spatio-temporal patterns of ET are present as result of heterogeneity in land cover, land use and climatic conditions. In this respect, spaceborne remote sensing (RS) provides the only alternative to continuously measure surface parameters related to ET over large areas. The Royal Meteorological Institute (RMI) of Belgium, in the framework of EUMETSAT's "Land Surface Analysis-Satellite Application Facility" (LSA-SAF), has developed a model for the estimation of ET. The model is forced by RS data, numerical weather predictions and land cover information. The RS forcing is derived from measurements by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard the Meteosat Second Generation (MSG) satellite. This ET model is operational and delivers ET estimations over the whole field of view of the MSG satellite (Europe, Africa and Eastern South America) (http://landsaf.meteo.pt) every 30 minutes. The spatial resolution of MSG is 3 x 3 km at subsatellite point and about 4 x 5 km in continental Europe. The spatial resolution of this product may constrain its full exploitation as the interest of potential users (farmers and natural resources scientists) may lie on smaller spatial units. This study aimed at testing methodological alternatives to combine RS imagery (geostationary and polar orbit satellites) for the estimation of ET such that the spatial resolution of the final product is improved. In particular, the study consisted in the implementation of two approaches for combining the current ET estimations with

  18. Three-dimensional, two-species magnetohydrodynamic studies of the early time behaviors of the Combined Release and Radiation Effects Satellite G2 barium release

    SciTech Connect

    Xie, Lianghai Li, Lei; Wang, Jingdong; Zhang, Yiteng

    2014-04-15

    We present a three-dimensional, two-species (Ba{sup +} and H{sup +}) MHD model to study the early time behaviors of a barium release at about 1 R{sub E} like Combined Release and Radiation Effects Satellite G2, with emphasis placed on the three-dimensional evolution of the barium cloud and its effects on the ambient plasma environment. We find that the perturbations caused by the cloud are the combined results of the initial injection, the radial expansion, and the diamagnetic effect and propagate as fast MHD waves in the magnetosphere. In return, the transverse expansion and the cross-B motion of barium ions are constrained by the magnetic force, which lead to a field-aligned striation of ions and the decoupling of these ions from the neutrals. Our simulation shows the formation and collapse of the diamagnetic cavity in the barium cloud. The estimated time scale for the cavity evolution might be much shorter if photoionization time scale and field aligned expansion of barium ions are considered. In addition, our two species MHD simulation also finds the snowplow effect resulting from the momentum coupling between barium ions and background H{sup +}, which creates density hole and bumps in the background H{sup +} when barium ions expanding along the magnetic field lines.

  19. Combining satellite-based fire observations and ground-based lightning detections to identify lightning fires across the conterminous USA

    USGS Publications Warehouse

    Bar-Massada, A.; Hawbaker, T.J.; Stewart, S.I.; Radeloff, V.C.

    2012-01-01

    Lightning fires are a common natural disturbance in North America, and account for the largest proportion of the area burned by wildfires each year. Yet, the spatiotemporal patterns of lightning fires in the conterminous US are not well understood due to limitations of existing fire databases. Our goal here was to develop and test an algorithm that combined MODIS fire detections with lightning detections from the National Lightning Detection Network to identify lightning fires across the conterminous US from 2000 to 2008. The algorithm searches for spatiotemporal conjunctions of MODIS fire clusters and NLDN detected lightning strikes, given a spatiotemporal lag between lightning strike and fire ignition. The algorithm revealed distinctive spatial patterns of lightning fires in the conterminous US While a sensitivity analysis revealed that the algorithm is highly sensitive to the two thresholds that are used to determine conjunction, the density of fires it detected was moderately correlated with ground based fire records. When only fires larger than 0.4 km2 were considered, correlations were higher and the root-mean-square error between datasets was less than five fires per 625 km2 for the entire study period. Our algorithm is thus suitable for detecting broad scale spatial patterns of lightning fire occurrence, and especially lightning fire hotspots, but has limited detection capability of smaller fires because these cannot be consistently detected by MODIS. These results may enhance our understanding of large scale patterns of lightning fire activity, and can be used to identify the broad scale factors controlling fire occurrence.

  20. Using combined records of IceBridge and satellite-derived thickness and extent data to constrain future projections of Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Stroeve, J. C.; Barrett, A. P.; Laxon, S.; Serreze, M. C.

    2012-12-01

    Confidence in climate models to provide reliable projections of future climate is largely built on how well they can reproduce observed features of recent climate. Although all models participating in the 5th Phase of the Coupled Model Intercomparison Project (CMIP5) show declining Arctic sea ice over the period of observations, trends from most models remain smaller than observed. The ability of climate models to capture the observed variability in the sea ice extent depends in part on how well they are able to simulate the observed sea ice thickness distribution, since models with an overly thick initial ice cover tend to lose their summer ice cover later than models with initially thinner ice given the same climatic forcing. While long-term, basin-wide sea ice thickness data are not available for the Arctic Ocean, a combination of satellite data from ERS1/2, ICESat, and Cryosat, together with sea ice thicknesses derived from data from NASA's Operation IceBridge, provide a record of the evolution of ice thickness across the Arctic from the early 1990s to present. Submarine sonar data are used to extend the record further back in time but coverage is more limited. This data illustrates that the thickest ice is found north of the Canadian Archipelago, with thinner ice along the Eurasian side of the Arctic. We use the combined records of satellite- and air-borne sea ice thickness data from the early 1990s to present to evaluate how well CMIP5 models capture the spatial distribution of the mean winter ice thickness fields and how this relates to the observed summer trends in sea ice extent. Performance metrics are developed for models representations of observed sea ice extent and thickness. Metrics are used as a basis for conditioning probabalistic predictions of sea ice cover in the Arctic. Three approaches are used for conditioning predictions; 1) a selection of a subset of best performing models based on thickness and extent metrics; 2) a weighting of all models

  1. Satellite Bioclimatology.

    NASA Astrophysics Data System (ADS)

    Goward, Samuel N.

    1989-07-01

    Satellite-acquired, remotely sensed observations of the earth's land areas are substatially advancing knowledge of global vegetation patterns. Recognition that combined visible/near infrared spectral reflectance observations are a general indicator of the presence, condition and magnitude of vegetation foliage provides a basis for explanation. This information is of considerable value in climatic research because of the links between climate variables and vegetation foliage. Presence of vegetation foliage is predominantly determined by a combination of local beat and moisture conditions. In turn, foliar presence determines local rates of photosynthesis, affects surface albedo, and influences local rates of evapotranspiration as well as other elements of surface energy/mass balance. Availability of these remotely sensed data provides, for the first time, a consistent, global means to directly study interactions between climate and vegetation. This understanding is now being incorporated in climatological research and should improve understanding of macroscale bioclimatology. Remote sensing technology and understanding of this technology are continuing to develop rapidly and further major advances in this new field of `satellite bioclimatology' can be expected in the near future.

  2. Satellite communications

    NASA Astrophysics Data System (ADS)

    Saha, M. K.

    1982-11-01

    The paper describes the basic principles and the historial development of satellite communications. Various satellite systems for global communications are discused and compared. Some typical operational communication satellite systems summary including geostationary systems are presented. Considerations leading to the system design including the link design for various multiple access techniques and the future trends in satellite communications systems are also discussed.

  3. Satellite communications

    NASA Astrophysics Data System (ADS)

    Rubin, Philip A.

    A review of the economic and technological status of the satellite communications industry is presented. The history of satellite communications is outlined, focusing on the launching of Syncom III in 1963. The basic operation of communication satellites is explained. The differences between C and Ku frequency bands are examined. Economic issues related to satellite communications are discussed in detail.

  4. Prediction of error rates in dose-imprinted memories on board CRRES by two different methods. [Combined Release and Radiation Effects Satellite

    NASA Technical Reports Server (NTRS)

    Brucker, G. J.; Stassinopoulos, E. G.

    1991-01-01

    An analysis of the expected space radiation effects on the single event upset (SEU) properties of CMOS/bulk memories onboard the Combined Release and Radiation Effects Satellite (CRRES) is presented. Dose-imprint data from ground test irradiations of identical devices are applied to the predictions of cosmic-ray-induced space upset rates in the memories onboard the spacecraft. The calculations take into account the effect of total dose on the SEU sensitivity of the devices as the dose accumulates in orbit. Estimates of error rates, which involved an arbitrary selection of a single pair of threshold linear energy transfer (LET) and asymptotic cross-section values, were compared to the results of an integration over the cross-section curves versus LET. The integration gave lower upset rates than the use of the selected values of the SEU parameters. Since the integration approach is more accurate and eliminates the need for an arbitrary definition of threshold LET and asymptotic cross section, it is recommended for all error rate predictions where experimental sigma-versus-LET curves are available.

  5. Combining Forces - The Use of Landsat TM Satellite Imagery, Soil Parameter Information, and Multiplex PCR to Detect Coccidioides immitis Growth Sites in Kern County, California

    PubMed Central

    Lauer, Antje; Talamantes, Jorge; Castañón Olivares, Laura Rosío; Medina, Luis Jaime; Baal, Joe Daryl Hugo; Casimiro, Kayla; Shroff, Natasha; Emery, Kirt W.

    2014-01-01

    Coccidioidomycosis is a fungal disease acquired through the inhalation of spores of Coccidioides spp., which afflicts primarily humans and other mammals. It is endemic to areas in the southwestern United States, including the San Joaquin Valley portion of Kern County, California, our region of interest (ROI). Recently, incidence of coccidioidomycosis, also known as valley fever, has increased significantly, and several factors including climate change have been suggested as possible drivers for this observation. Up to date details about the ecological niche of C. immitis have escaped full characterization. In our project, we chose a three-step approach to investigate this niche: 1) We examined Landsat-5-Thematic-Mapper multispectral images of our ROI by using training pixels at a 750 m×750 m section of Sharktooth Hill, a site confirmed to be a C. immitis growth site, to implement a Maximum Likelihood Classification scheme to map out the locations that could be suitable to support the growth of the pathogen; 2) We used the websoilsurvey database of the US Department of Agriculture to obtain soil parameter data; and 3) We investigated soil samples from 23 sites around Bakersfield, California using a multiplex Polymerase Chain Reaction (PCR) based method to detect the pathogen. Our results indicated that a combination of satellite imagery, soil type information, and multiplex PCR are powerful tools to predict and identify growth sites of C. immitis. This approach can be used as a basis for systematic sampling and investigation of soils to detect Coccidioides spp. PMID:25380290

  6. Supporting FIRE-suppression strategies combining fire spread MODelling and SATellite data in an operational context in Portugal: the FIRE-MODSAT project

    NASA Astrophysics Data System (ADS)

    Sá, Ana C. L.; Benali, Akli; Pinto, Renata M. S.; Pereira, José M. C.; Trigo, Ricardo M.; DaCamara, Carlos C.

    2014-05-01

    Large wildfires are infrequent but account for the most severe environmental, ecological and socio-economic impacts. In recent years Portugal has suffered the impact of major heat waves that fuelled records of burnt area exceeding 400.000ha and 300.000ha in 2003 and 2005, respectively. According to the latest IPCC reports, the frequency and amplitude of summer heat waves over Iberia will very likely increase in the future. Therefore, most climate change studies point to an increase in the number and extent of wildfires. Thus, an increase in both wildfire impacts and fire suppression difficulties is expected. The spread of large wildfires results from a complex interaction between topography, meteorology and fuel properties. Wildfire spread models (e.g. FARSITE) are commonly used to simulate fire growth and behaviour and are an essential tool to understand their main drivers. Additionally, satellite active-fire data have been used to monitor the occurrence, extent, and spread of wildfires. Both satellite data and fire spread models provide different types of information about the spatial and temporal distribution of large wildfires and can potentially be used to support strategic decisions regarding fire suppression resource allocation. However, they have not been combined in a manner that fully exploits their potential and minimizes their limitations. A knowledge gap still exists in understanding how to minimize the impacts of large wildfires, leading to the following research question: What can we learn from past large wildfires in order to mitigate future fire impacts? FIRE-MODSAT is a one-year funded project by the Portuguese Foundation for the Science and Technology (FCT) that is founded on this research question, with the main goal of improving our understanding on the interactions between fire spread and its environmental drivers, to support fire management decisions in an operational context and generate valuable information to improve the efficiency of the

  7. Multi-scale model of the ionosphere from the combination of modern space-geodetic satellite techniques - project status and first results

    NASA Astrophysics Data System (ADS)

    Schmidt, M.; Hugentobler, U.; Jakowski, N.; Dettmering, D.; Liang, W.; Limberger, M.; Wilken, V.; Gerzen, T.; Hoque, M.; Berdermann, J.

    2012-04-01

    Near real-time high resolution and high precision ionosphere models are needed for a large number of applications, e.g. in navigation, positioning, telecommunications or astronautics. Today these ionosphere models are mostly empirical, i.e., based purely on mathematical approaches. In the DFG project 'Multi-scale model of the ionosphere from the combination of modern space-geodetic satellite techniques (MuSIK)' the complex phenomena within the ionosphere are described vertically by combining the Chapman electron density profile with a plasmasphere layer. In order to consider the horizontal and temporal behaviour the fundamental target parameters of this physics-motivated approach are modelled by series expansions in terms of tensor products of localizing B-spline functions depending on longitude, latitude and time. For testing the procedure the model will be applied to an appropriate region in South America, which covers relevant ionospheric processes and phenomena such as the Equatorial Anomaly. The project connects the expertise of the three project partners, namely Deutsches Geodätisches Forschungsinstitut (DGFI) Munich, the Institute of Astronomical and Physical Geodesy (IAPG) of the Technical University Munich (TUM) and the German Aerospace Center (DLR), Neustrelitz. In this presentation we focus on the current status of the project. In the first year of the project we studied the behaviour of the ionosphere in the test region, we setup appropriate test periods covering high and low solar activity as well as winter and summer and started the data collection, analysis, pre-processing and archiving. We developed partly the mathematical-physical modelling approach and performed first computations based on simulated input data. Here we present information on the data coverage for the area and the time periods of our investigations and we outline challenges of the multi-dimensional mathematical-physical modelling approach. We show first results, discuss problems

  8. Physical analysis on improving the recovery accuracy of the Earth's gravity field by a combination of satellite observations in along-track and cross-track directions

    NASA Astrophysics Data System (ADS)

    Zheng, Wei; Hsu, Hou-Tse; Zhong, Min; Yun, Mei-Juan

    2014-10-01

    The physical investigations on the accuracy improvement to the measurement of the Earth's gravity field recovery are carried out based on the next-generation Pendulum-A/B out-of-plane twin-satellite formation in this paper. Firstly, the Earth's gravity field complete up to degree and order 100 is, respectively, recovered by the collinear and pendulum satellite formations using the orbital parameters of the satellite and the matching accuracies of key payloads from the twin GRACE satellites. The research results show that the accuracy of the Earth's gravity field model from the Pendulum-A/B satellite formation is about two times higher than from the collinear satellite formation, and the further improvement of the determination accuracy of the Earth's gravity field model is feasible by the next-generation Pendulum-A/B out-of-plane twin-satellite formation. Secondly, the Earth's gravity field from Pendulum-A/B complete up to degree and order 100 is accurately recovered based on the orbital parameters of the satellite (e.g., an orbital altitude of 400 km, an intersatellite range of 100 km, an orbital inclination of 89° and an orbital eccentricity of 0.001), the matching accuracies of space-borne instruments (e.g. 10-6 m in the intersatellite range, 10-3 m in the orbital position, 10-6 m/s in orbital velocity, and 10-11 m/s2 in non-conservative force), an observation time of 30 days and a sampling interval of 10 s. The measurement accuracy of the Earth's gravity field from the next-generation Pendulum-A/B out-of-plane twin-satellite formation is full of promise for being improved by about 10 times compared with that from the current GRACE satellite formation. Finally, the physical requirements for the next-generation Pendulum-A/B out-of-plane twin-satellite formation are analyzed, and it is proposed that the satellite orbital altitude be preferably designed to be close to 400±50 km and the matching precision of key sensors from the Pendulum-A/B mission be about one

  9. Mapping post-fire forest regeneration and vegetation recovery using a combination of very high spatial resolution and hyperspectral satellite imagery

    NASA Astrophysics Data System (ADS)

    Mitri, George H.; Gitas, Ioannis Z.

    2013-02-01

    Careful evaluation of forest regeneration and vegetation recovery after a fire event provides vital information useful in land management. The use of remotely sensed data is considered to be especially suitable for monitoring ecosystem dynamics after fire. The aim of this work was to map post-fire forest regeneration and vegetation recovery on the Mediterranean island of Thasos by using a combination of very high spatial (VHS) resolution (QuickBird) and hyperspectral (EO-1 Hyperion) imagery and by employing object-based image analysis. More specifically, the work focused on (1) the separation and mapping of three major post-fire classes (forest regeneration, other vegetation recovery, unburned vegetation) existing within the fire perimeter, and (2) the differentiation and mapping of the two main forest regeneration classes, namely, Pinus brutia regeneration, and Pinus nigra regeneration. The data used in this study consisted of satellite images and field observations of homogeneous regenerated and revegetated areas. The methodology followed two main steps: a three-level image segmentation, and, a classification of the segmented images. The process resulted in the separation of classes related to the aforementioned objectives. The overall accuracy assessment revealed very promising results (approximately 83.7% overall accuracy, with a Kappa Index of Agreement of 0.79). The achieved accuracy was 8% higher when compared to the results reported in a previous work in which only the EO-1 Hyperion image was employed in order to map the same classes. Some classification confusions involving the classes of P. brutia regeneration and P. nigra regeneration were observed. This could be attributed to the absence of large and dense homogeneous areas of regenerated pine trees in the study area.

  10. A combined deficit index for regional agricultural drought assessment over semi-arid tract of India using geostationary meteorological satellite data

    NASA Astrophysics Data System (ADS)

    Vyas, Swapnil S.; Bhattacharya, Bimal K.; Nigam, Rahul; Guhathakurta, Pulak; Ghosh, Kripan; Chattopadhyay, N.; Gairola, R. M.

    2015-07-01

    The untimely onset and uneven distribution of south-west monsoon rainfall lead to agricultural drought causing reduction in food-grain production with high vulnerability over semi-arid tract (SAT) of India. A combined deficit index (CDI) has been developed from tri-monthly sum of deficit in antecedent rainfall and deficit in monthly vegetation vigor with a lag period of one month between the two. The formulation of CDI used a core biophysical (e.g., NDVI) and a hydro-meteorological (e.g., rainfall) variables derived using observation from Indian geostationary satellites. The CDI was tested and evaluated in two drought years (2009 and 2012) within a span of five years (2009-2013) over SAT. The index was found to have good correlation (0.49-0.68) with standardized precipitation index (SPI) computed from rain-gauge measurements but showed lower correlation with anomaly in monthly land surface temperature (LST). Significant correlations were found between CDI and reduction in agricultural carbon productivity (0.67-0.83), evapotranspiration (0.64-0.73), agricultural grain yield (0.70-0.85). Inconsistent correlation between CDI and ET reduction was noticed in 2012 in contrast to consistent correlation between CDI and reduction in carbon productivity both in 2009 and 2012. The comparison of CDI-based drought-affected area with those from existing operational approach showed 75% overlapping regions though class-to-class matching was only 40-45%. The results demonstrated that CDI is a potential indicator for assessment of late-season regional agricultural drought based on lag-response between water supply and crop vigor.

  11. Satellite (IRLS) tracking of elk

    NASA Technical Reports Server (NTRS)

    Buechner, H. K.

    1972-01-01

    The practicability of tracking free roaming animals in natural environments by satellite systems is reported. Satellite systems combine continuous tracking with simultaneous monitoring of physiological and environmental parameters through a combination of radio tracking and biotelemetric ground systems that lead to a better understanding of animal behavior and migration patterns.

  12. Application of spectral analysis techniques to the intercomparison of aerosol data - Part 4: Combined maximum covariance analysis to bridge the gap between multi-sensor satellite retrievals and ground-based measurements

    NASA Astrophysics Data System (ADS)

    Li, J.; Carlson, B. E.; Lacis, A. A.

    2014-04-01

    The development of remote sensing techniques has greatly advanced our knowledge of atmospheric aerosols. Various satellite sensors and the associated retrieval algorithms all add to the information of global aerosol variability, while well-designed surface networks provide time series of highly accurate measurements at specific locations. In studying the variability of aerosol properties, aerosol climate effects, and constraining aerosol fields in climate models, it is essential to make the best use of all of the available information. In the previous three parts of this series, we demonstrated the usefulness of several spectral decomposition techniques in the analysis and comparison of temporal and spatial variability of aerosol optical depth using satellite and ground-based measurements. Specifically, Principal Component Analysis (PCA) successfully captures and isolates seasonal and interannual variability from different aerosol source regions, Maximum Covariance Analysis (MCA) provides a means to verify the variability in one satellite dataset against Aerosol Robotic Network (AERONET) data, and Combined Principal Component Analysis (CPCA) realized parallel comparison among multi-satellite, multi-sensor datasets. As the final part of the study, this paper introduces a novel technique that integrates both multi-sensor datasets and ground observations, and thus effectively bridges the gap between these two types of measurements. The Combined Maximum Covariance Analysis (CMCA) decomposes the cross covariance matrix between the combined multi-sensor satellite data field and AERONET station data. We show that this new method not only confirms the seasonal and interannual variability of aerosol optical depth, aerosol source regions and events represented by different satellite datasets, but also identifies the strengths and weaknesses of each dataset in capturing the variability associated with sources, events or aerosol types. Furthermore, by examining the spread of

  13. Application of spectral analysis techniques to the intercomparison of aerosol data - Part 4: Synthesized analysis of multisensor satellite and ground-based AOD measurements using combined maximum covariance analysis

    NASA Astrophysics Data System (ADS)

    Li, J.; Carlson, B. E.; Lacis, A. A.

    2014-08-01

    In this paper, we introduce the usage of a newly developed spectral decomposition technique - combined maximum covariance analysis (CMCA) - in the spatiotemporal comparison of four satellite data sets and ground-based observations of aerosol optical depth (AOD). This technique is based on commonly used principal component analysis (PCA) and maximum covariance analysis (MCA). By decomposing the cross-covariance matrix between the joint satellite data field and Aerosol Robotic Network (AERONET) station data, both parallel comparison across different satellite data sets and the evaluation of the satellite data against the AERONET measurements are simultaneously realized. We show that this new method not only confirms the seasonal and interannual variability of aerosol optical depth, aerosol-source regions and events represented by different satellite data sets, but also identifies the strengths and weaknesses of each data set in capturing the variability associated with sources, events or aerosol types. Furthermore, by examining the spread of the spatial modes of different satellite fields, regions with the largest uncertainties in aerosol observation are identified. We also present two regional case studies that respectively demonstrate the capability of the CMCA technique in assessing the representation of an extreme event in different data sets, and in evaluating the performance of different data sets on seasonal and interannual timescales. Global results indicate that different data sets agree qualitatively for major aerosol-source regions. Discrepancies are mostly found over the Sahel, India, eastern and southeastern Asia. Results for eastern Europe suggest that the intense wildfire event in Russia during summer 2010 was less well-represented by SeaWiFS (Sea-viewing Wide Field-of-view Sensor) and OMI (Ozone Monitoring Instrument), which might be due to misclassification of smoke plumes as clouds. Analysis for the Indian subcontinent shows that here SeaWiFS agrees

  14. Combining Landsat TM multispectral satellite imagery and different modelling approaches for mapping post-fire erosion changes in a Mediterranean site

    NASA Astrophysics Data System (ADS)

    Petropoulos, George P.; Kairis, Orestis; Karamesouti, Mina; Papanikolaou, Ioannis D.; Kosmas, Constantinos

    2013-04-01

    South European countries are naturally vulnerable to wildfires. Their natural resources such as soil, vegetation and water may be severely affected by wildfires, causing an imminent environmental deterioration due to the complex interdependence among biophysical components. Soil surface water erosion is a natural process essential for soil formation that is affected by such interdependences. Accelerated erosion due to wildfires, constitutes a major restrictive factor for ecosystem sustainability. In 2007, South European countries were severely affected by wildfires, with more than 500,000 hectares of land burnt in that year alone, well above the average of the last 30 years. The present work examines the changes in spatial variability of soil erosion rates as a result of a wildfire event that took place in Greece in 2007, one of the most devastating years in terms of wildfire hazards. Regional estimates of soil erosion rates before and after the fire outbreak were derived from the Revised Universal Soil Loss Equation (RUSLE, Renard et al. 1991) and the Pan-European Soil Erosion Risk Assessment model (PESERA, Kirkby, 1999; Kirkby et al., 2000). Inputs for both models included climatic, land-use, soil type, topography and land use management data. Where appropriate, both models were also fed with input data derived from the analysis of LANDSAT TM satellite imagery available in our study area, acquired before and shortly after the fire suppression. Our study was compiled and performed in a GIS environment. In overall, the loss of vegetation from the fire outbreak caused a substantial increase of soil erosion rates in the affected area, particularly towards the steep slopes. Both tested models were compared to each other and noticeable differences were observed in the soil erosion predictions before and after the fire event. These are attributed to the different parameterization requirements of the 2 models. This quantification of sediment supply through the river

  15. Satellite RNAs and Satellite Viruses.

    PubMed

    Palukaitis, Peter

    2016-03-01

    Satellite RNAs and satellite viruses are extraviral components that can affect either the pathogenicity, the accumulation, or both of their associated viruses while themselves being dependent on the associated viruses as helper viruses for their infection. Most of these satellite RNAs are noncoding RNAs, and in many cases, have been shown to alter the interaction of their helper viruses with their hosts. In only a few cases have the functions of these satellite RNAs in such interactions been studied in detail. In particular, work on the satellite RNAs of Cucumber mosaic virus and Turnip crinkle virus have provided novel insights into RNAs functioning as noncoding RNAs. These effects are described and potential roles for satellite RNAs in the processes involved in symptom intensification or attenuation are discussed. In most cases, models describing these roles involve some aspect of RNA silencing or its suppression, either directly or indirectly involving the particular satellite RNA. PMID:26551994

  16. Cloudsat and MTSAT Satellites Observer Atsani

    NASA Video Gallery

    This Aug. 19 image combines cloud imagery from Japan's MTSAT satellite and NASA's CloudSat satellite. Areas of pink and red designate larger amounts of liquid and ice. Light blue indicate smaller c...

  17. Satellite oceanography - The instruments

    NASA Technical Reports Server (NTRS)

    Stewart, R. H.

    1981-01-01

    It is pointed out that no instrument is sensitive to only one oceanographic variable; rather, each responds to a combination of atmospheric and oceanic phenomena. This complicates data interpretation and usually requires that a number of observations, each sensitive to somewhat different phenomena, be combined to provide unambiguous information. The distinction between active and passive instruments is described. A block diagram illustrating the steps necessary to convert data from satellite instruments into oceanographic information is included, as is a diagram illustrating the operation of a radio-frequency radiometer. Attention is also given to the satellites that carry the various oceanographic instruments.

  18. Reconstruction of SO2 emission height time-series and plume age using a combination of satellite imagery, volcanic tremor and back trajectory modelling at Mt. Etna

    NASA Astrophysics Data System (ADS)

    Pardini, Federica; Burton, Mike; Salerno, Giuseppe; Merucci, Luca; Corradini, Stefano; Barsotti, Sara; de'Michieli Vitturi, Mattia; di Grazia, Giuseppe

    2015-04-01

    While much work has focused on detection of volcanic gas emissions from space, relatively little progress has been made on examining volcanic processes using satellite measurements of volcanic plumes. In theory, much information can be derived regarding the temporal evolution of an eruption from a single image of an eruption plume. This information could be used to constrain models of magma chamber emptying, and comparison with InSAR measurements of syn-eruptive deflation. The over-arching goal of the work presented here therefore is SO2 flux time-series reconstruction using satellite imagery of SO2 in volcanic plumes. One of the major sources of uncertainty in the determination of SO2 abundances from satellite imagery is the plume height, and so we have focused on the development of a robust procedure that allows us to make accurate reconstructions of plume height time series. Starting from satellite images of SO2 emitted from Mt. Etna, Italy, we identified specific pixels where SO2 was detected and utilized the HYSPLIT Lagrangian back-trajectory model in order to retrieve the emission height and time of the eruption column over the volcano. The results have been refined using a probabilistic approach that allows calculation of the most probable emission height range. Previous work has highlighted that volcanic tremor is strongly connected to eruption intensity, and therefore, potentially to plume height. We therefore examined the relationship between volcanic tremor measured on Etna with our derived plume height time series. We discovered a relatively good agreement between the time series, suggesting that the physical processes controlling both the distribution of SO2 in the atmosphere and the intensity of volcanic tremor are strongly coupled, through the explosivity of the eruptive activity. The synthesis of volcanic tremor and derived plume heights is a novel new approach, and opens the possibility of more quantitative analysis of SO2 amounts in satellite

  19. THE ONE ROOM SATELLITE.

    ERIC Educational Resources Information Center

    DREYFUS, LEE S.

    A WISCONSIN HIGH SCHOOL FRENCH CLASS AND A GROUP OF STUDENTS IN AN ENGLISH CALSS AT THE LYCEE HENRI IV OF PARIS, FRANCE, PARTICIPATED IN A COMBINED CLASS SESSION IN THE FIRST INTERNATIONAL TV CLASSROOM EXCHANGE. THE TV SIGNALS WERE EXCHANGED BY MEANS OF THE EARLY BIRD SATELLITE AND PERMITTED THE STUDENTS TO EXCHANGE MESSAGES. DURING THE TELECAST…

  20. Satellite myths

    NASA Astrophysics Data System (ADS)

    Easton, Roger L.; Hall, David

    2008-01-01

    Richard Corfield's article “Sputnik's legacy” (October 2007 pp23-27) states that the satellite on board the US Vanguard rocket, which exploded during launch on 6 December 1957 two months after Sputnik's successful take-off, was “a hastily put together contraption of wires and circuitry designed only to send a radio signal back to Earth”. In fact, the Vanguard satellite was developed over a period of several years and put together carefully using the best techniques and equipment available at the time - such as transistors from Bell Laboratories/Western Electric. The satellite contained not one but two transmitters, in which the crystal-controlled oscillators had been designed to measure both the temperature of the satellite shell and of the internal package.

  1. Satellite Videoconferences

    NASA Technical Reports Server (NTRS)

    1990-01-01

    NASA is helping thousands of teachers to learn more about aerospace matters, improve their classroom skills, and expand significantly the content of their aerospace education curricula by means of live educational satellite videoconferences. The 1 1/2 hour 'Update for Teachers' programs originate at Oklahoma State University (OSU) Telecommunications Center. The television signals are transmitted to the WESTAR IV communications satellite, which remits them to participating schools across the U.S. and in parts of Mexico and Canada. The schools are equipped with small home style satellite reception dishes. Education Satellite Videoconference programs are conducted four times yearly, covering a variety of aerospace subjects. Teachers can call toll-free and have questions answered after the speaker's presentations. Information about NASA educational resources and how to obtain them will be provided.

  2. Satellite observations

    NASA Astrophysics Data System (ADS)

    1984-05-01

    In 1982 and 1983, six scientific satellites were operated successfully. Two of them, JIKIKEN and ISS-b, performed observations of the Earth's plasma environment. HINOTORI, the solar maximum satellite, observed a number of solar flares. HAKUCHO and newly launched TENMA conducted various observations of cosmic X-ray sources. HIMAWARI-2 is a meteorological satellite but its payload includes a solar particle monitor. EXOS-C was successfully launched in February, 1983, and participants in the MAP (Middle Atmosphere Program). Following these missions, the PLANET-A project comprising two missions, MS-T5 and PLANET-A, is under preparation for the participation in the international cooperative exploration of Comet P/Halley. The third X-ray astronomy satellite ASTRO-C is currently scheduled for 1987 launch.

  3. Mapping urban heat islands of arctic cities using combined data on field measurements and satellite images based on the example of the city of Apatity (Murmansk Oblast)

    NASA Astrophysics Data System (ADS)

    Konstantinov, P. I.; Grishchenko, M. Y.; Varentsov, M. I.

    2015-12-01

    This article presents the results of a study of the urban heat island (UHI) in the city of Apatity during winter that were obtained according to the data of field meteorological measurements and satellite images. Calculations of the surface layer temperature have been made based on the surface temperature data obtained from satellite images. The experimental data on air temperature were obtained as a result of expeditionary meteorological observations, and the experimental data on surface temperature were obtained based on the data of the space hyperspectral Moderate-Resolution Imaging Spectroradiometer (MODIS) system, channels 31 and 32 (10.78-11.28 and 11.77-12.27 micrometers, respectively). As a result of the analysis of temperature fields, an intensive heat island (up to 3.2°C) has been identified that was estimated based on the underlying surface temperature, and its mean intensity over the observation period significantly exceeds the representative data for European cities in winter. It has also been established that the air temperature calculated according to the MODIS data is systematically higher under winter conditions than the air temperature from direct measurement data.

  4. Satellite altitude determination uncertainties

    NASA Technical Reports Server (NTRS)

    Siry, J. W.

    1972-01-01

    Satellite altitude determination uncertainties will be discussed from the standpoint of the GEOS-C satellite, from the longer range viewpoint afforded by the Geopause concept. Data are focused on methods for short-arc tracking which are essentially geometric in nature. One uses combinations of lasers and collocated cameras. The other method relies only on lasers, using three or more to obtain the position fix. Two typical locales are looked at, the Caribbean area, and a region associated with tracking sites at Goddard, Bermuda and Canada which encompasses a portion of the Gulf Stream in which meanders develop.

  5. Evaluation of Temperature and Material Combinations on Several Lubricants for Use in the Geostationary Operational Environmental Satellite (GOES) Mission Filter Wheel Bearings

    NASA Technical Reports Server (NTRS)

    Jansen, Mark J.; Jones, William R., Jr.; Predmore, Roamer E.

    2001-01-01

    A bearing test apparatus was used to investigate lubricant degradation rates and elastohydrodynamic transition temperatures for several perfluoropolyether (Krytox) formulations, a pentasilahydrocarbon, and a synthetic hydrocarbon (Pennzane 2001 A) in an MPB 1219 bearing, which is used in the geostationary operational environmental satellite (GOES) mission filter wheel assembly. Test conditions were the following: 1000-hr duration, 75 C, 20 lb axial load, vacuum level less than 1 x 10(exp -6) Torr, and a 600-rpm rotational speed. Baseline tests were performed using unformulated Krytox 143AB, the heritage lubricant. Krytox additive formulations showed small reductions in degradation rate. Krytox GPL-105, a higher viscosity version, yielded the least amount of degradation products. Both the silahydrocarbon and Pennzane 2001A showed no signs of lubricant degradation and had ample amounts of free oil at test conclusion.

  6. Earth resources satellite systems for flood monitoring

    NASA Technical Reports Server (NTRS)

    Mcginnis, D. F.; Rango, A.

    1975-01-01

    The environmental satellites NOAA-2 and ERTS-1 observed flooding in United States' rivers such as the Mississippi during 1973. Combination of NOAA-2 observation frequency and the ERTS-1 resolution provides an adequate satellite system for monitoring floods. Several polar-orbiting satellites of the ERTS type could view flooded areas at a reasonably high resolution every three to five days. A high-resolution earth-synchronous satellite would further enhance flood mapping by providing observations whenever clouds are absent.

  7. Centriolar Satellites

    PubMed Central

    Kubo, Akiharu; Sasaki, Hiroyuki; Yuba-Kubo, Akiko; Tsukita, Shoichiro; Shiina, Nobuyuki

    1999-01-01

    We identified Xenopus pericentriolar material-1 (PCM-1), which had been reported to constitute pericentriolar material, cloned its cDNA, and generated a specific pAb against this molecule. Immunolabeling revealed that PCM-1 was not a pericentriolar material protein, but a specific component of centriolar satellites, morphologically characterized as electron-dense granules, ∼70–100 nm in diameter, scattered around centrosomes. Using a GFP fusion protein with PCM-1, we found that PCM-1–containing centriolar satellites moved along microtubules toward their minus ends, i.e., toward centrosomes, in live cells, as well as in vitro reconstituted asters. These findings defined centriolar satellites at the molecular level, and explained their pericentriolar localization. Next, to understand the relationship between centriolar satellites and centriolar replication, we examined the expression and subcellular localization of PCM-1 in ciliated epithelial cells during ciliogenesis. When ciliogenesis was induced in mouse nasal respiratory epithelial cells, PCM-1 immunofluorescence was markedly elevated at the apical cytoplasm. At the electron microscopic level, anti–PCM-1 pAb exclusively labeled fibrous granules, but not deuterosomes, both of which have been suggested to play central roles in centriolar replication in ciliogenesis. These findings suggested that centriolar satellites and fibrous granules are identical novel nonmembranous organelles containing PCM-1, which may play some important role(s) in centriolar replication. PMID:10579718

  8. Small satellites

    NASA Technical Reports Server (NTRS)

    Thomas, P.; Veverka, J.; Dermott, S.

    1986-01-01

    Satellites smaller than Mimas (r = 195 km) are distinguished by irregular overall shapes and by rough limb topography. Material properties and impact cratering dominate the shaping of these objects. Long fragmentation histories can produce a variety of internal structures, but so far there is no direct evidence that any small satellite is an equilibrium ellipsoid made up of noncohesive gravitationally bound rubble. One many bodies that orbit close to their primary the tidal and rotational components of surface gravity strongly affect the directions of local g and thereby affect the redistribution of regolith by mass wasting. Downslope movement of regolith is extensive on Deimos, and is probably effective on many other small satellites. It is shown that in some cases observed patterns of downslope mass wasting cold produce useful constraints on the satellite's mean density. The diversity of features seen in the few high-resolution images of small satellites currently available suggests that these objects have undergone complex histories of cratering, fragmentation, and regolith evolution.

  9. Linked Autonomous Interplanetary Satellite Orbit Navigation

    NASA Technical Reports Server (NTRS)

    Parker, Jeffrey S.; Anderson, Rodney L.; Born, George H.; Leonard, Jason M.; McGranaghan, Ryan M.; Fujimoto, Kohei

    2013-01-01

    A navigation technology known as LiAISON (Linked Autonomous Interplanetary Satellite Orbit Navigation) has been known to produce very impressive navigation results for scenarios involving two or more cooperative satellites near the Moon, such that at least one satellite must be in an orbit significantly perturbed by the Earth, such as a lunar halo orbit. The two (or more) satellites track each other using satellite-to-satellite range and/or range-rate measurements. These relative measurements yield absolute orbit navigation when one of the satellites is in a lunar halo orbit, or the like. The geometry between a lunar halo orbiter and a GEO satellite continuously changes, which dramatically improves the information content of a satellite-to-satellite tracking signal. The geometrical variations include significant out-of-plane shifts, as well as inplane shifts. Further, the GEO satellite is almost continuously in view of a lunar halo orbiter. High-fidelity simulations demonstrate that LiAISON technology improves the navigation of GEO orbiters by an order of magnitude, relative to standard ground tracking. If a GEO satellite is navigated using LiAISON- only tracking measurements, its position is typically known to better than 10 meters. If LiAISON measurements are combined with simple radiometric ground observations, then the satellite s position is typically known to better than 3 meters, which is substantially better than the current state of GEO navigation. There are two features of LiAISON that are novel and advantageous compared with conventional satellite navigation. First, ordinary satellite-to-satellite tracking data only provides relative navigation of each satellite. The novelty is the placement of one navigation satellite in an orbit that is significantly perturbed by both the Earth and the Moon. A navigation satellite can track other satellites elsewhere in the Earth-Moon system and acquire knowledge about both satellites absolute positions and velocities

  10. Structure and evolution of the Molucca Sea area: constraints based on interpretation of a combined sea-surface and satellite gravity dataset

    NASA Astrophysics Data System (ADS)

    Widiwijayanti, Christina; Mikhailov, Valentin; Diament, Michel; Deplus, Christine; Louat, Rémy; Tikhotsky, Sergei; Gvishiani, Alexei

    2003-10-01

    The paper presents an interpretation of the complete Bouguer gravity anomaly for the Molucca Sea area (northeast of Indonesia) in order to investigate the structure and interrelation of the main tectonic units of the region. Data on the gravity field and topography incorporate all available shipboard and satellite-derived data, including data collected during a 1994 R/V L'Atalante cruise in the Molucca Sea (MODEC). These data were compiled by weighted interpolation of surface and satellite data. The anomalous gravity field of the area contains components of different wavelengths, which we separated into regional and local anomalies using a spherical analogue of Kolmogorov-Wiener optimal (mean-square) filtering. Position and depth of the shallow lithospheric gravity sources were then estimated from the local field component by applying a new approach to Euler solution selection based on a recently developed fuzzy logic clustering method, called RODIN. The spatial distribution and depth of Euler solutions provide new information on the tectonic structure of the upper lithosphere resulting from the convergence of the Philippine Sea, Eurasian and Australian plates. The local Bouguer anomalies and dense clusters of Euler solutions make it easy to trace the Sangihe Trench further north, up to 5.5°N, joining it to the Pujada and Miangas ridges and to trace the Miangas Ridge southwards to its junction with the Central Ridge. Seismic data revealing compressive structure and dense shallow clusters of Euler solutions suggest that the Pujada Ridge overthrusts the Miangas Ridge from the west. Clusters of Euler solutions also clearly outline an ophiolite body of the Talaud Archipelago, show main thrust zones bounding it, and trace the southern termination of the Philippine Fault horsetail structure up to 5.5-6°N in the area southeast of Mindanao Island. Our results support the hypothesis that the Talaud Archipelago was formed in situ as an uplifted Central Ridge block. We

  11. Satellite broadcasting

    NASA Astrophysics Data System (ADS)

    Gregory, D.; Rainger, P.; Harvey, R. V.; Jennings, A.

    Questions related to direct broadcasting satellites are addressed with attention given to celestial mechanics, synchronous orbits, propagation, international plans, domestic installation, related laws and system costs. The role of the World Administrative Planning Conference (WARC) organization is discussed and contrasted with that of the regional administrative radio conference. Topics related to the field of law include coverage and overspill, regulation and control, copyrights and international organizations. Alternative ways of estimating direct broadcasting system costs are presented with consideration given to satellite costs as a function of mass, launch costs and system costs as a function of power.

  12. Combining digital elevation data (SRTM/ASTER), high resolution satellite imagery (Quickbird) and GIS for geomorphological mapping: A multi-component case study on Mediterranean karst in Central Crete

    NASA Astrophysics Data System (ADS)

    Siart, Christoph; Bubenzer, Olaf; Eitel, Bernhard

    2009-11-01

    Remote sensing data have become more and more popular for geomorphological investigations because their steadily increasing level of detail and accessibility opens up new potentials. In this context, this paper examines the application and quality of digital elevation models (SRTM and ASTER DEMs), high resolution satellite imagery (Quickbird) and GIS techniques for the detection and mapping of karst landforms (mainly enclosed depressions) at different scales in the Ida Mountains of Central Crete. Besides discussing methodological issues and evaluating suitability potentials, we conducted an exemplary case study based on spatial analysis of the regional karst morphology. Different input datasets and processing methods are applied (GIS-based analysis, land cover classification, raster calculations, etc.) in order to carry out an area-wide surveying and mapping of karst depressions. The findings are supported and validated by auxiliary field studies. Due to the level of detail and occasional data errors, an exclusive use of satellite imagery or digital elevation models for automatic karst landform detection performs insufficiently. Our results demonstrate that mapping karst features through remote sensing is significantly dependent on scale of interest, existing environmental conditions and data quality. A semi-automatic data integration approach on the basis of digital datasets generated by combined satellite image processing and DEM analysis yields the best results, especially when indirect karst-indicating variables like iron oxide-rich sediments are included as detection criteria. The multi-component application presented in this paper provides a time-saving and effective tool for meso- to macro-scale object detection and extensive study areas. However, the potential of fully automated karst feature mapping still needs to be explored in future work. Concerning the spatial dimension of karstification in Central Crete, the GIS-based results allow differentiating

  13. Some background about satellites

    NASA Technical Reports Server (NTRS)

    Burns, Joseph A.

    1986-01-01

    Four tables of planetary and satellite data are presented which list satellite discoveries, planetary parameters, satellite orbits, and satellite physical properties respectively. A scheme for classifying the satellites is provided and it is noted that most known moons fall into three general classes: regular satellites, collisional shards, and irregular satellites. Satellite processes are outlined with attention given to origins, dynamical and thermal evolution, surface processes, and composition and cratering. Background material is provided for each family of satellites.

  14. Digging up your dirt. High school students combine small-scale respiration and soil carbon measurements with satellite imagery in hands-on inquiry activities.

    NASA Astrophysics Data System (ADS)

    Kemper, K.; Throop, H.

    2015-12-01

    One of the greatest impacts on the global carbon cycle is changes in land use. Making this concept relevant and inquiry-based for high school students is challenging. Many are familiar with reconstructing paleo-climate from ice core data, but few have a connection to current climate research. Many students ask questions like 'What will our area be like in 20 years?' or 'How much does planting trees help?' while few have the scientific language to engage in a discussion to answer these questions. Our work connects students to climate change research in several ways: first, teacher Keska Kemper engaged in field research with Dr. Heather Throop creating a 'teacher in the field' perspective for students in the classroom. Dr. Throop met with Keska Kemper's students several times to develop an inquiry-based field study. Students predicted and then measured rates of respiration between different soil types in an urban park close to their school. Students then could compare their results from Portland, Oregon to Throop's work across a rain gradient in Australia. Discussions about percent tree cover and soil carbon helped students see connections between land use changes and changes in carbon cycling. Last, students examined satellite imagery to determine percent tree cover and numberss of trees to compare to soil carbon in the same region. Students were able to examine imagery over the last 30 years to visualize land use changes in the greater Portland area.

  15. Satellite description

    NASA Astrophysics Data System (ADS)

    Gillett, F. C.; Clegg, P. E.; Neugebauer, G.; Langford, D.; Pouw, A.; Irace, W.; Houck, J.

    The onboard computers and their associated software, the attitude control system, and data recording and the communication links of the infrared astronomy satellite (TRAS) are discussed. The IRAS telescope system is considered in detail. Attention is directed towards the cryogenics, thermal control, optics, focal plane assembly, and electronics associated with the telescope system.

  16. Combining shipboard in situ data with satellite data to estimate daily primary production in a coastal upwelling system: A data mining approach

    NASA Astrophysics Data System (ADS)

    Williamson, Robert I.; Field, John G.; Shillington, Frank A.; Jarre, Astrid; Potgieter, Anet

    2015-11-01

    This study classifies coastal time-series data according to subsurface phytoplankton vertical distributions to be able to capture the variability of primary production at fine spatial and temporal scales. Our method uses algorithms developed to extract patterns in large datasets of time-sequential data. We use short time-series of QuikSCAT surface winds, MODIS sea surface temperature and surface chlorophyll a associated with each in situ chlorophyll a profile, as well as the season and bottom depth of the in situ station to discover patterns that can be used to classify new data into 12 profile classes. We first fill in missing MODIS data using a conditional random field model so that cloudy days are not excluded. The most likely profile is then predicted using all the available data. We apply our method to the St Helena Bay area, a region within the productive Benguela Current upwelling system. A profile is predicted for each day and each pixel of 4 km resolution satellite image for 16 consecutive months. Each profile is used in a broad-band photosynthesis model to produce a daily three-dimensional estimate of gross primary production. An average production rate of 3.2 g C m-2 day-1 was obtained for the area, which shows very good agreement with other estimates from the region. The results show persistent high productivity near the surface throughout the year with the exception of the winter months. Deeper in the water column productivity is more seasonal. The 16 month time-series highlights the interannual, seasonal and daily variability of the system. By linking physical processes to the distribution of phytoplankton at appropriate spatio-temporal scales, we can now more rigorously investigate bottom-up driven impacts on ecosystems characterised by short-term variability.

  17. Exploring the link between urban form and work related transportation using combined satellite image and census information: Case of the Great lakes region

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Guindon, Bert; Sun, Krista

    2016-05-01

    Aspects of urban transportation have significant implications for resource consumption and environmental quality. The level of travel activity, the viability of various modes of transportation and hence the level of transportation-related emissions are influenced by the structure of cities, i.e., their urban forms. While it is widely recognized that satellite remote sensing can provide spatial information on urban land cover and land use, its effective use for understanding impacts of urban form on issues such as transportation requires that this information be integrated with relevant demographic information. A comprehensive bi-national urban database, the Great Lakes Urban Survey (GLUS), comprising all cities with populations in excess of 200,000 has been created from Landsat imagery and national census and transportation survey information from Canada and the United States. A suite of analysis tools are proposed to utilize information sets such as GLUS to investigate the link between urban form and work-related travel. A new indicator, the Employment Deficit Measure (EDM), is proposed to quantify the balance between employment and worker availability at different transit horizons and hence to assess the viability of alternate modes of transportation. It is argued that the high degree of residential and commercial/industrial land uses greatly impact travel to work mode options as well as commute distance. A spatial interaction model is developed and found to accurately predict travel distance aggregated at the census tract level. We argue that this model could also be used to explore the relative levels of travel activity associated with different urban forms.

  18. Satellite TV in the UK

    NASA Astrophysics Data System (ADS)

    Stanyard, Roger

    1991-11-01

    The development of DBS TV is considered in terms of the type of supporting satellite to be selected with attention given to the medium-power concept FSS satellites. Predictions are made regarding the combination direct-to-home/DBS satellite-broadcasting industry emphasizing the use of DBS TV for program delivery and not as a substitute for cable and other distribution methods. DBS TV is an effective technology for reaching audience segments that cannot be included by conventional terrestrial and cable means.

  19. Satellite voice broadcast system study, volume 2

    NASA Technical Reports Server (NTRS)

    Horstein, M.

    1985-01-01

    This study investigates the feasibility of providing Voice of America (VOA) broadcasts by satellite relay, rather than via terrestrial relay stations. Satellite voice broadcast systems are described for three different frequency bands: HF (26 MHz), VHF (68 MHz), and L-band (1.5 GHz). The geographical areas of interest at HF and L-band include all major land masses worldwide with the exception of the U.S., Canada, and Australia. Geostationary satellite configurations are considered for both frequency bands. In addition, a system of subsynchronous, circular satellites with an orbit period of 8 hours is developed for the HF band. VHF broadcasts, which are confined to the Soviet Union, are provied by a system of Molniya satellites. Satellites intended for HF or VHF broadcastinbg are extremely large and heavy. Satellite designs presented here are limited in size and weight to the capability of the STS/Centaur launch vehicle combination. Even so, at HF it would take 47 geostationary satellites or 20 satellites in 8-hour orbits to fully satisfy the voice-channel requirements of the broadcast schedule provided by VOA. On the other hand, three Molniya satellites suffice for the geographically restricted schedule at VHF. At L-band, only four geostationary satellites are needed to meet the requirements of the complete broadcast schedule. Moreover, these satellites are comparable in size and weight to current satellites designed for direct broadcast of video program material.

  20. Virtual Satellite

    NASA Technical Reports Server (NTRS)

    Hammrs, Stephan R.

    2008-01-01

    Virtual Satellite (VirtualSat) is a computer program that creates an environment that facilitates the development, verification, and validation of flight software for a single spacecraft or for multiple spacecraft flying in formation. In this environment, enhanced functionality and autonomy of navigation, guidance, and control systems of a spacecraft are provided by a virtual satellite that is, a computational model that simulates the dynamic behavior of the spacecraft. Within this environment, it is possible to execute any associated software, the development of which could benefit from knowledge of, and possible interaction (typically, exchange of data) with, the virtual satellite. Examples of associated software include programs for simulating spacecraft power and thermal- management systems. This environment is independent of the flight hardware that will eventually host the flight software, making it possible to develop the software simultaneously with, or even before, the hardware is delivered. Optionally, by use of interfaces included in VirtualSat, hardware can be used instead of simulated. The flight software, coded in the C or C++ programming language, is compilable and loadable into VirtualSat without any special modifications. Thus, VirtualSat can serve as a relatively inexpensive software test-bed for development test, integration, and post-launch maintenance of spacecraft flight software.

  1. Combination of optical and LiDAR satellite imagery with forest inventory data to improve wall-to-wall assessment of growing stock in Italy

    NASA Astrophysics Data System (ADS)

    Maselli, F.; Chiesi, M.; Mura, M.; Marchetti, M.; Corona, P.; Chirici, G.

    2014-02-01

    The acquisition of information about growing stock is a fundamental step in the framework of forest management planning and scenario modeling, besides being essential for assessing the amount of carbon stored within forest ecosystems. Gallaun et al. (2010) produced a pan-European map of forest growing stock by the combination of ground and remotely sensed data. The first objective of the current paper is to assess the accuracy of this map versus the ground data collected during the latest Italian National Forest Inventory (INFC). Next, a new wall-to-wall estimation of growing stock is obtained by combining ground measurements of four regional forest inventories with the CORINE land cover map of Italy and the global canopy height map derived from Geoscience Laser Altimeter System (GLAS) and Moderate Resolution Imaging Spectroradiometer (MODIS) data. More particularly, the growing stock measurements of the four inventories are stratified by ecosystem type and extended over all Italian forest areas through the application of locally weighted regressions to the GLAS/MODIS canopy height map. When compared to the INFC measurements, the new map shows higher accuracy than that by Gallaun et al., particularly for high growing stock values. The coefficient of determination between estimated and INFC growing stocks is improved by about 0.5, whilst the mean square error is reduced from 90 to 48 m3 ha-1.

  2. A core/shell/satellite anticancer platform for 808 NIR light-driven multimodal imaging and combined chemo-/photothermal therapy

    NASA Astrophysics Data System (ADS)

    Yang, Guixin; Lv, Ruichan; He, Fei; Qu, Fengyu; Gai, Shili; Du, Shaokang; Wei, Zibo; Yang, Piaoping

    2015-08-01

    In this contribution, a novel multifunctional anti-cancer nanoplatform has been firstly constructed by conjugating a photothermal agent (CuS nanoparticles) and a cancer cell target agent (folic acid, FA) onto the surface of mesoporous silica coated core-shell-shell up-conversion nanoparticles (UCNPs). It was found that the doxorubicin (DOX) loaded system exhibits obvious pH and NIR-responsive release behaviour and the drug can be targetedly delivered to the cancer cells by a receptor mediated endocytosis manner. Furthermore, both photothermal therapy (PTT) and chemotherapy can be triggered simultaneously by a single 808 nm near infrared (NIR) light source, thus leading to a synergistic effect. The combined chemo- and NIR photothermal therapy can significantly improve the therapeutic efficacy compared to any single therapy, which has been evidenced by both in vitro and in vivo results. Besides, due to the doped rare earth ions, the platform also exhibits good up-conversion luminescence (UCL), computed tomography (CT) and magnetic resonance imaging (MRI) properties. Based on the excellent multimodal imaging and anti-tumor properties, the multifunctional nanoplatform should be a promising candidate for imaging-guided anti-cancer therapy.In this contribution, a novel multifunctional anti-cancer nanoplatform has been firstly constructed by conjugating a photothermal agent (CuS nanoparticles) and a cancer cell target agent (folic acid, FA) onto the surface of mesoporous silica coated core-shell-shell up-conversion nanoparticles (UCNPs). It was found that the doxorubicin (DOX) loaded system exhibits obvious pH and NIR-responsive release behaviour and the drug can be targetedly delivered to the cancer cells by a receptor mediated endocytosis manner. Furthermore, both photothermal therapy (PTT) and chemotherapy can be triggered simultaneously by a single 808 nm near infrared (NIR) light source, thus leading to a synergistic effect. The combined chemo- and NIR photothermal

  3. Combined Satellite and Surface-Based Estimation of the Intracloud/ Cloud-to-Ground Lightning Ratio Over the Continental United States

    NASA Technical Reports Server (NTRS)

    Boccippio, D. J.; Cummins, K.; Christian, H. J.; Goodman, S. J.

    1999-01-01

    Four years of observations from the NASA Optical Transient Detector (OTD) and Global Atmospherics National Lightning Detection Network (NLDN) are combined to determine the geographic distribution of the intracloud/cloud to ground lightning ratio over the continental United States. The mean ratio over this region is 2.64-2.94, with a standard deviation of 1.1-1.3 and anomalies as low as 1.0 or less over the Rocky and Appalachian mountains and as high as 8-10 in the central-upper midwest. There is some indication that the ratio covaries with ground elevation, although the relationship is nonunique. Little evidence is found to support a latitudinal covariance, despite significant variation in the climatological mean tropopause pressure over the latitudes considered. The dynamic range of local variability is comparable to the range of values cited by previous studies for latitudinal variation from the deep tropics to midlatitudes. Local high anomalies of this ratio in the midwest are coincident with anomalies in the climatological percentage of positive CG occurrence, as well as in the occurrence of large positive CGs characteristic of MCS convective and trailing stratiform regions. This suggests that storm type, morphology and level of organization may dominate over environmental cofactors in the local determination of this ratio.

  4. Meteorological satellites

    NASA Astrophysics Data System (ADS)

    1981-10-01

    Meteor-2 (second generation meteorological satellite) and an experimental satellite on which instruments are being tested and modified for the requirements of hydrometeorology and a determination of natural resources are presently operational in the U.S.S.R. Television devices with a 1-10 km terrain image resolution operating in the visible and infrared region are used to determine the space system, velocity and direction of cloud movements and provide information about the snow and ice cover, cyclones, storms, vortices in the atmosphere, and velocity and direction of wind. Images with a 50-1000 m resolution make possible geological and hydrological surveys, an evaluation of the state of vegetation and crops, detection of forest fires, determination of pollution of the atmosphere and sea and determination of optimal fishing regions in the ocean. Measurement of the intensity of atmospheric radiation in narrow infrared regions and very high frequencies allows remote evaluation of the temperature and humidity distribution in the vertical cross section of the Earth's atmosphere.

  5. Synchronous Earth Observatory Satellite /SEOS/

    NASA Technical Reports Server (NTRS)

    Walter, L. S.

    1974-01-01

    NASA/GSFC is currently studying the applications and technical requirements for a Synchronous Earth Observations Satellite (SEOS). Such a satellite would combine the relatively high resolution and multi-spectral capability of the Earth Resources Technology Satellite (ERTS) with the on-station continuous monitoring of the Synchronous Meteorological Satellite (SMS). SEOS capability is geared to perform disaster warning of tornadoes and floods as well as to monitor transient phenomena affecting earth resources (e.g., green waves and algae blooms). The heart of the system is a Large Earth Survey Telescope (LEST) which has a designed 1.5 meter diameter. Spectral bands in the visible, near- and far-infrared have been selected to optimize SEOS utility. A microwave sounder will be used in conjunction with the LEST for meteorological applications.

  6. Small satellite radiometric measurement system

    SciTech Connect

    Weber, P.G.

    1992-01-01

    A critical need for the US Global Change Research Program is to provide continuous, well-calibrated radiometric data for the earth`s radiation budget. This paper describes a new, compact, relatively light-weight, adaptable radiometer which will provide both spectrally integrated measurements and data in selected spectral bands. The radiometer design is suitable for use on small satellites, aircraft, or remotely piloted aircraft (RPAs). An example of the implementation of this radiometer on a small satellite is given. Significant benefits derive from simultaneous measurements of specific narrow (in wavelength) spectral features; such data may be obtained by combining LARI with a compact spectrometer on the same platform. Well-chosen satellite orbits allow one to use data from other satellites (e.g. DMSP) to enhance the data product, or to provide superior coverage of specific locations. 23 refs.

  7. Microwave intersatellite links for communications satellites

    NASA Technical Reports Server (NTRS)

    Welti, G. R.

    1982-01-01

    Applications and interface requirements for intersatellite links (ISLs) between commercial communications satellites are reviewed, ranging from ISLs between widely separated satellites to ISLs between clustered satellites. On-board processing architectures for ISLs employing a variety of modulation schemes are described. These schemes include FM remodulation and QPSK regeneration in combination with switching and buffering. The various architectures are compared in terms of complexity, required performance, antenna size, mass, and power.

  8. Multi-mission Satellite Management

    NASA Astrophysics Data System (ADS)

    Jamilkowski, M. L.; Teter, M. A.; Grant, K. D.; Dougherty, B.; Cochran, S.

    2015-12-01

    NOAA's next-generation environmental satellite, the Joint Polar Satellite System (JPSS) replaces the current Polar-orbiting Operational Environmental Satellites (POES). JPSS satellites carry sensors which collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The first JPSS satellite was launched in 2011 and is currently NOAA's primary operational polar satellite. The JPSS ground system is the Common Ground System (CGS), and provides command, control, and communications (C3) and data processing (DP). A multi-mission system, CGS provides combinations of C3/DP for numerous NASA, NOAA, DoD, and international missions. In preparation for the next JPSS satellite, CGS improved its multi-mission capabilities to enhance mission operations for larger constellations of earth observing satellites with the added benefit of streamlining mission operations for other NOAA missions. CGS's multi-mission capabilities allows management all of assets as a single enterprise, more efficiently using ground resources and personnel and consolidating multiple ground systems into one. Sophisticated scheduling algorithms compare mission priorities and constraints across all ground stations, creating an enterprise schedule optimized to mission needs, which CGS executes to acquire the satellite link, uplink commands, downlink and route data to the operations and data processing facilities, and generate the final products for delivery to downstream users. This paper will illustrate the CGS's ability to manage multiple, enterprise-wide polar orbiting missions by demonstrating resource modeling and tasking, production of enterprise contact schedules for NOAA's Fairbanks ground station (using both standing and ad hoc requests), deconflicting resources due to ground outages, and updating resource allocations through dynamic priority definitions.

  9. The status of environmental satellites and availability of their data products

    NASA Technical Reports Server (NTRS)

    Hughes, C. L.; Campbell, C. E.

    1977-01-01

    The latest available information about the status of unclassified environmental satellite (flown by the United States) and their data products is presented. The type of environmental satellites discussed include unmanned earth resource and meteorological satellites, and manned satellites which can act as a combination platform for instruments. The capabilities and data products of projected satellites are discussed along with those of currently operating systems.

  10. Satellite altimetry

    NASA Technical Reports Server (NTRS)

    Cheney, Robert E.

    1992-01-01

    Since altimetry data are not really old enough to use the term data archaeology, Mr. Cheney referred to the stewardship of these data. He noted that it is very important to document the basis for an altimetry data set as the algorithms and corrections used to arrive at the Geophysical Data Record (GDR) have been improving and are continuing to improve the precision of sea level data derived from altimetry. He noted that the GEOSAT Exact Repeat Mission (ERM) data set has recently been reprocessed by his organization in the National Ocean Service of NOAA and made available to the scientific community on CD/ROM disks by the National Oceanographic Data Center of the U.S. (NODC). The new data set contains a satellite orbit more precise by an order of magnitude together with an improved water vapor correction. A new, comprehensive GDR Handbook has also been prepared.

  11. Satellites in Education.

    ERIC Educational Resources Information Center

    Jones, David

    1988-01-01

    Describes the methods and materials used to obtain satellite pictures from weather satellites. Discusses possible physics lessons which can be done using this equipment including orbital mechanics, and how the satellite works. (CW)

  12. A satellite for demonstration of Panel Extension Satellite (PETSAT)

    NASA Astrophysics Data System (ADS)

    Sugawara, Yoshiki; Sahara, Hironori; Nakasuka, Shinichi; Greenland, Stephen; Morimoto, Takeshi; Koyama, Kanichi; Kobayashi, Chisato; Kikuchi, Hideaki; Okada, Takanori; Tanaka, Hidenori

    2008-07-01

    This paper presents the current status, configuration, architecture, and key technologies of SOHLA-2, the demonstration mission of the PETSAT (Panel ExTension SATellite) concept. The PETSAT proposal is for a modular satellite consisting of any number of unfolding functional panels. These panels are designed around an open architecture and connected through standardized interfaces. The interfaces between panels incorporate a reliable "plug-in" format, such that when combined, the integrated system takes on the intended satellite function in a redundant and distributed manner. By combining the different panel types in any number and configuration, flexibility to mission requirements is achieved. Some panels for performing basic satellite functions will be available as commercial-off-the-shelf components, and others custom developed dependent on the mission. During launch these panels are stowed in a folded low volume configuration, which is then extended on-orbit, realizing a satellite with a large area for the mounting of solar arrays, mission systems, extensible booms, or any other components. SOHLA-2 is both a concept demonstration and a lightning detection mission in the VHF band. It weighs less than 50 kg and consists of six panels: communication, attitude control, propulsion, mission, experiment and bus function. The bus function panel is based on the successful Cubesat XI developed at the University of Tokyo and this acts as the manager of the technology demonstration aspects for the mission. By basing the architecture upon a proven technology, the reliability of the satellite is increased. It is intended that the satellite be launched in early 2008.

  13. Assimilation of Satellite Ozone Observations

    NASA Technical Reports Server (NTRS)

    Stajner, I.; Winslow, N.; Wargan, K.; Hayashi, H.; Pawson, S.; Rood, R.

    2003-01-01

    This talk will discuss assimilation of ozone data from satellite-borne instruments. Satellite observations of ozone total columns and profiles have been measured by a series of Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter Ultraviolet (SBUV) instruments, and more recently by the Global Ozone Monitoring Experiment. Additional profile data are provided by instruments on NASA's Upper Atmosphere Research Satellite and by occultation instruments on other platforms. Instruments on Envisat' and future EOS Aura satellite will supply even more comprehensive data about the ozone distribution. Satellite data contain a wealth of information, but they do not provide synoptic global maps of ozone fields. These maps can be obtained through assimilation of satellite data into global chemistry and transport models. In the ozone system at NASA's Data Assimilation Office (DAO) any combination of TOMS, SBUV, and Microwave Limb sounder (MLS) data can be assimilated. We found that the addition of MLS to SBUV and TOMS data in the system helps to constrain the ozone distribution, especially in the polar night region and in the tropics. The assimilated ozone distribution in the troposphere and lower stratosphere is sensitive also to finer changes in the SBUV and TOMS data selection and to changes in error covariance models. All results are established by comparisons of assimilated ozone with independent profiles from ozone sondes and occultation instruments.

  14. Iodine Satellite

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Dankanich, John; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Iodine Satellite (iSat) spacecraft will be the first CubeSat to demonstrate high change in velocity from a primary propulsion system by using Hall thruster technology and iodine as a propellant. The mission will demonstrate CubeSat maneuverability, including plane change, altitude change and change in its closest approach to Earth to ensure atmospheric reentry in less than 90 days. The mission is planned for launch in fall 2017. Hall thruster technology is a type of electric propulsion. Electric propulsion uses electricity, typically from solar panels, to accelerate the propellant. Electric propulsion can accelerate propellant to 10 times higher velocities than traditional chemical propulsion systems, which significantly increases fuel efficiency. To enable the success of the propulsion subsystem, iSat will also demonstrate power management and thermal control capabilities well beyond the current state-of-the-art for spacecraft of its size. This technology is a viable primary propulsion system that can be used on small satellites ranging from about 22 pounds (10 kilograms) to more than 1,000 pounds (450 kilograms). iSat's fuel efficiency is ten times greater and its propulsion per volume is 100 times greater than current cold-gas systems and three times better than the same system operating on xenon. iSat's iodine propulsion system consists of a 200 watt (W) Hall thruster, a cathode, a tank to store solid iodine, a power processing unit (PPU) and the feed system to supply the iodine. This propulsion system is based on a 200 W Hall thruster developed by Busek Co. Inc., which was previously flown using xenon as the propellant. Several improvements have been made to the original system to include a compact PPU, targeting greater than 80 percent reduction in mass and volume of conventional PPU designs. The cathode technology is planned to enable heaterless cathode conditioning, significantly increasing total system efficiency. The feed system has been designed to

  15. Outer planet satellites

    SciTech Connect

    Schenk, P.M. )

    1991-01-01

    Recent findings on the outer-planet satellites are presented, with special consideration given to data on the rheologic properties of ice on icy satellites, the satellite surfaces and exogenic processes, cratering on dead cratered satellites, volcanism, and the interiors of outer-planet satellites. Particular attention is given to the state of Titan's surface and the properties of Triton, Pluto, and Charon. 210 refs.

  16. Asteroid Satellites

    NASA Astrophysics Data System (ADS)

    Merline, W. J.

    2001-11-01

    Discovery and study of small satellites of asteroids or double asteroids can yield valuable information about the intrinsic properties of asteroids themselves and about their history and evolution. Determination of the orbits of these moons can provide precise masses of the primaries, and hence reliable estimates of the fundamental property of bulk density. This reveals much about the composition and structure of the primary and will allow us to make comparisons between, for example, asteroid taxonomic type and our inventory of meteorites. The nature and prevalence of these systems will also give clues as to the collisional environment in which they formed, and have further implications for the role of collisions in shaping our solar system. A decade ago, binary asteroids were more of a theoretical curiosity. In 1993, the Galileo spacecraft allowed the first undeniable detection of an asteroid moon, with the discovery of Dactyl, a small moon of Ida. Since that time, and particularly in the last year, the number of known binaries has risen dramatically. Previously odd-shaped and lobate near-Earth asteroids, observed by radar, have given way to signatures indicating, almost certainly, that at least four NEAs are binary systems. The tell-tale lightcurves of several other NEAs reveal a high likelihood of being double. Indications are that among the NEAs, there may be a binary frequency of several tens of percent. Among the main-belt asteroids, we now know of 6 confirmed binary systems, although their overall frequency is likely to be low, perhaps a few percent. The detections have largely come about because of significant advances in adaptive optics systems on large telescopes, which can now reduce the blurring of the Earth's atmosphere to compete with the spatial resolution of space-based imaging (which itself, via HST, is now contributing valuable observations). Most of these binary systems have similarities, but there are important exceptions. Searches among other

  17. Satellite voice broadcase system study. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Horstein, M.

    1985-01-01

    The feasibility of providing Voice of America (VOA) broadcasts by satellite relay was investigated. Satellite voice broadcast systems are described for three different frequency bands: HF, FHV, and L-band. Geostationary satellite configurations are considered for both frequency bands. A system of subsynchronous, circular satellites with an orbit period of 8 hours was developed for the HF band. The VHF broadcasts are provided by a system of Molniya satellites. The satellite designs are limited in size and weight to the capability of the STS/Centaur launch vehicle combination. At L-band, only four geostationary satellites are needed to meet the requirements of the complete broadcast schedule. These satellites are comparable in size and weight to current satellites designed for the direct broadcast of video program material.

  18. Stream Gauges and Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Alsdorf, D. E.

    2010-12-01

    within an international river basin (this is also an argument for better diplomacy). Essentially, where gauges exist, satellite measurements allow the spatial extension of in-situ observations, especially when jointly combined in models such as data assimilation methods. The opportunity for new hydrologic science and discovery is enhanced when the strengths of traditional and new measurements are combined.

  19. Weather Satellite Enterprise Information Chain

    NASA Astrophysics Data System (ADS)

    Jamilkowski, M. L.; Grant, K. D.; Miller, S. W.; Cochran, S.

    2015-12-01

    NOAA & NASA are acquiring the next-generation civilian operational weather satellite: Joint Polar Satellite System (JPSS). Contributing the afternoon orbit & ground system (GS) to replace current NOAA POES Satellites, its sensors will collect meteorological, oceanographic & climatological data. The JPSS Common Ground System (CGS), consisting of C3 and IDP segments, is developed by Raytheon. It now flies the Suomi National Polar-orbiting Partnership (S-NPP) satellite, transferring data between ground facilities, processing them into environmental products for NOAA weather centers, and expanding to support JPSS-1 in 2017. As a multi-mission system, CGS provides combinations of C3, data processing, and product delivery for numerous NASA, NOAA, DoD and international missions.The CGS provides a wide range of support to a number of missions: Command and control and mission management for the S-NPP mission today, expanding this support to the JPSS-1 satellite mission in 2017 Data acquisition for S-NPP, the JAXA's Global Change Observation Mission - Water (GCOM-W1), POES, and the Defense Meteorological Satellite Program (DMSP) and Coriolis/WindSat for the DoD Data routing over a global fiber network for S-NPP, JPSS-1, GCOM-W1, POES, DMSP, Coriolis/WindSat, NASA EOS missions, MetOp for EUMETSAT and the National Science Foundation Environmental data processing and distribution for S-NPP, GCOM-W1 and JPSS-1 The CGS plays a key role in facilitating the movement and value-added enhancement of data all the way from satellite-based sensor data to delivery to the consumers who generate forecasts and produce watches and warnings. This presentation will discuss the information flow from sensors, through data routing and processing, and finally to product delivery. It will highlight how advances in architecture developed through lessons learned from S-NPP and implemented for JPSS-1 will increase data availability and reduce latency for end user applications.

  20. Shadow imaging of geosynchronous satellites

    NASA Astrophysics Data System (ADS)

    Douglas, Dennis Michael

    Geosynchronous (GEO) satellites are essential for modern communication networks. If communication to a GEO satellite is lost and a malfunction occurs upon orbit insertion such as a solar panel not deploying there is no direct way to observe it from Earth. Due to the GEO orbit distance of ~36,000 km from Earth's surface, the Rayleigh criteria dictates that a 14 m telescope is required to conventionally image a satellite with spatial resolution down to 1 m using visible light. Furthermore, a telescope larger than 30 m is required under ideal conditions to obtain spatial resolution down to 0.4 m. This dissertation evaluates a method for obtaining high spatial resolution images of GEO satellites from an Earth based system by measuring the irradiance distribution on the ground resulting from the occultation of the satellite passing in front of a star. The representative size of a GEO satellite combined with the orbital distance results in the ground shadow being consistent with a Fresnel diffraction pattern when observed at visible wavelengths. A measurement of the ground shadow irradiance is used as an amplitude constraint in a Gerchberg-Saxton phase retrieval algorithm that produces a reconstruction of the satellite's 2D transmission function which is analogous to a reverse contrast image of the satellite. The advantage of shadow imaging is that a terrestrial based redundant set of linearly distributed inexpensive small telescopes, each coupled to high speed detectors, is a more effective resolved imaging system for GEO satellites than a very large telescope under ideal conditions. Modeling and simulation efforts indicate sub-meter spatial resolution can be readily achieved using collection apertures of less than 1 meter in diameter. A mathematical basis is established for the treatment of the physical phenomena involved in the shadow imaging process. This includes the source star brightness and angular extent, and the diffraction of starlight from the satellite

  1. Visualizing Airborne and Satellite Imagery

    NASA Technical Reports Server (NTRS)

    Bierwirth, Victoria A.

    2011-01-01

    Remote sensing is a process able to provide information about Earth to better understand Earth's processes and assist in monitoring Earth's resources. The Cloud Absorption Radiometer (CAR) is one remote sensing instrument dedicated to the cause of collecting data on anthropogenic influences on Earth as well as assisting scientists in understanding land-surface and atmospheric interactions. Landsat is a satellite program dedicated to collecting repetitive coverage of the continental Earth surfaces in seven regions of the electromagnetic spectrum. Combining these two aircraft and satellite remote sensing instruments will provide a detailed and comprehensive data collection able to provide influential information and improve predictions of changes in the future. This project acquired, interpreted, and created composite images from satellite data acquired from Landsat 4-5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper plus (ETM+). Landsat images were processed for areas covered by CAR during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCT AS), Cloud and Land Surface Interaction Campaign (CLASIC), Intercontinental Chemical Transport Experiment-Phase B (INTEXB), and Southern African Regional Science Initiative (SAFARI) 2000 missions. The acquisition of Landsat data will provide supplemental information to assist in visualizing and interpreting airborne and satellite imagery.

  2. Cost and benefit of satellite shielding

    NASA Astrophysics Data System (ADS)

    Wiedemann, Carsten; Oswald, Michael; Stabroth, Sebastian; Alwes, Detlef; Vörsmann, Peter

    2008-07-01

    Recent simulations of the future development of the space debris environment revealed that the number of hypervelocity impacts on satellite surfaces will increase. Impacts of space debris particles and micrometeoroids can damage satellites. This can cause operational anomalies or even the loss of a satellite mission. The loss of a satellite reduces its expected operational lifetime. Thus, financial investments cannot be amortized completely. In this paper the cost of hypervelocity impacts on satellites is estimated. A risk analysis is performed by combining the probability of a penetration with the failure probability of the satellite. The goal of this work is to combine the risk of particle impacts with a cost analysis. The probability of a satellite failure is estimated by combining the probability of a penetration with a vulnerability model. The failure probability is weighted with the mission cost of a satellite. This results in a probability of loss of amortization. The amortization loss is used as estimation for the damage cost due to hypervelocity impacts. In this way it is possible to associate impacts with cost. The cost model is used to analyze selected reference missions. This analysis considers the influence of shielding measures on the mission cost. An important result is the estimation of the failure probability for different satellite wall designs including shielding. Shielding requires a modification of the satellite wall. This can result in an increasing complexity of the wall or an increasing mass. As a consequence, the hardware cost increase. To identify suitable shielding measures and to justify the additional financial investments, it is necessary to investigate the economic feasibility of such measures and to demonstrate their benefit.

  3. Small-satellite technology and applications III

    SciTech Connect

    Horais, B.J.

    1993-01-01

    This third conference on small-satellite applications has combined a number of significant and timely presentations on the status, in the US and on the international front, of this emerging industry. Presentations by all of the major Department of Defense activities in this field, including an overview of the ARPA CAMEO multispectral remote sensing satellite program, space activities at the Air Force Phillips Laboratory, and a space systems capabilities overview of the Naval Research Laboratory, are complemented by presentations from several international activities on their accomplishments and progress in the development of remote sensing satellite programs. For example: Spar Aerospace of Canada presented an overview of the progress they have made in establishing a space program through the use of small satellites, and the University of Surrey and Spar Aerospace provided an overview of the application of image compression schemes to imagery obtained from their UoSAT series of satellites. In addition, a number of papers were presented that summarize the state of technology in supporting activities, such as the development of the low-cost composite standardized satellite bus structures, accurate star trackers, and the application of JPEG and MPEG compression capabilities. Small-Satellite Technology and Applications III also addresses the business and cost estimating aspects of the emerging small-satellite industry as a means of increasing the overall awareness of the community in all aspects of developing a small-satellite remote sensing capability. Separate abstracts were prepared for 25 papers in this conference.

  4. Space Weather, Cosmic Rays, and Satellite Anomalies

    NASA Astrophysics Data System (ADS)

    Lev, Dorman

    Results are presented of the Satellite Anomaly Project, which aims to improve the methods of safeguarding satellites in the Earth’s magnetosphere from the negative effects of the space environment. Anomaly data from the USSR and Russian “Kosmos” series satellites in the period 1971-1999 are combined into one database, together with similar information on other spacecraft. This database contains, beyond the anomaly information, various characteristics of space weather: geomagnetic activity indices (Ap, AE and Dst), fluxes and fluencies of electrons and protons at different energies, high energy cosmic ray variations and other solar, interplanetary and solar wind data. A comparative analysis of the distribution of each of these parameters relative to satellite anomalies was carried out for the total number of anomalies (about 6000 events), and separately for high altitude orbit satellites ( 5000 events) and low altitude (about 800 events). No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies, averaged by a superposed epoch method around sudden storm commencements and proton event onsets for high (>1500 km) and low (<1500 km) altitude orbits revealed a big difference in behavior. Satellites were divided into several groups according to their orbital characteristics (altitude and inclination). The relation of satellite anomalies to the environmental parameters was found to be different for various orbits, and this should be taken into account when developing anomaly frequency models. The preliminary anomaly frequency models are presented.

  5. Satellite orbit predictor

    NASA Technical Reports Server (NTRS)

    Friedman, Morton l.; Garrett, James, Major

    An analog aid to determine satellite coverage of Emergency Locator Transmitters Emergency Position Indicating Radio Beacon (ELT/EPIRB) distress incidence is discussed. The satellite orbit predictor is a graphical aid for determining the relationship between the satellite orbit, antenna coverage of the spacecraft and coverage of the Local User Terminal. The predictor allows the user to quickly visualize if a selected position will probably be detected and is composed of a base map and a satellite track overlay for each satellite.A table of equator crossings for each satellite is included.

  6. China's satellite communications discussed

    NASA Astrophysics Data System (ADS)

    Ruhou, Z.

    1986-04-01

    In 1972, China began to enter the age of satellite comunications, and it was realized that satellites could play a large role in television transmission in China. The experimental broadcasting of satellite television programs was begun in 1978, and satisfactory results were obtained. The success of the television transmission demonstration has led to important decisions regarding development of a domestic satellite communications system. Before specialized communications satellites are launched, the decision was made to lease an international communications satellite transmitter. The responsibility of the ground stations were discussed.

  7. Galileo satellite antenna modeling

    NASA Astrophysics Data System (ADS)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  8. Infrared/microwave (IR/MW) micromirror array beam combiner design and analysis.

    PubMed

    Tian, Yi; Lv, Lijun; Jiang, Liwei; Wang, Xin; Li, Yanhong; Yu, Haiming; Feng, Xiaochen; Li, Qi; Zhang, Li; Li, Zhuo

    2013-08-01

    We investigated the design method of an infrared (IR)/microwave (MW) micromirror array type of beam combiner. The size of micromirror is in microscopic levels and comparable to MW wavelengths, so that the MW will not react in these dimensions, whereas the much shorter optical wavelengths will be reflected by them. Hence, the MW multilayered substrate was simplified and designed using transmission line theory. The beam combiner used an IR wavefront-division imaging technique to reflect the IR radiation image to the unit under test (UUT)'s pupil in a parallel light path. In addition, the boresight error detected by phase monopulse radar was analyzed using a moment-of method (MoM) and multilevel fast multipole method (MLFMM) acceleration technique. The boresight error introduced by the finite size of the beam combiner was less than 1°. Finally, in order to verify the wavefront-division imaging technique, a prototype of a micromirror array was fabricated, and IR images were tested. The IR images obtained by the thermal imager verified the correctness of the wavefront-division imaging technique. PMID:23913059

  9. Stereo Measurements from Satellites

    NASA Technical Reports Server (NTRS)

    Adler, R.

    1982-01-01

    The papers in this presentation include: 1) 'Stereographic Observations from Geosynchronous Satellites: An Important New Tool for the Atmospheric Sciences'; 2) 'Thunderstorm Cloud Top Ascent Rates Determined from Stereoscopic Satellite Observations'; 3) 'Artificial Stereo Presentation of Meteorological Data Fields'.

  10. Solar power satellite system definition study. Part 2, volume 5: Space operations (construction and transportation)

    NASA Technical Reports Server (NTRS)

    Miller, K.; Davis, E. E.

    1977-01-01

    Construction and transportation systems and operations are described for the following combinations: (1) silicon photovoltaic CR=1 satellite constructed primarily in low earth orbit (LEO); (2) silicon photovoltaic CR=1 satellite constructed in geosynchronous earth orbit (GEO); (3) Rankine thermal engine satellite constructed primarily in LEO; and (4) Rankine thermal engine satellite constructed in GEO.

  11. Communications satellite systems operations with the space station, volume 2

    NASA Technical Reports Server (NTRS)

    Price, K.; Dixon, J.; Weyandt, C.

    1987-01-01

    A financial model was developed which described quantitatively the economics of the space segment of communication satellite systems. The model describes the economics of the space system throughout the lifetime of the satellite. The expected state-of-the-art status of communications satellite systems and operations beginning service in 1995 were assessed and described. New or enhanced space-based activities and associated satellite system designs that have the potential to achieve future communications satellite operations in geostationary orbit with improved economic performance were postulated and defined. Three scenarios using combinations of space-based activities were analyzed: a spin stabilized satellite, a three axis satellite, and assembly at the Space Station and GEO servicing. Functional and technical requirements placed on the Space Station by the scenarios were detailed. Requirements on the satellite were also listed.

  12. Magnetospheres: Jupiter, Satellite Interactions

    NASA Astrophysics Data System (ADS)

    Neubauer, F.; Murdin, P.

    2000-11-01

    Most of the satellites of Jupiter, notably the large Galilean satellites Io, Europa, Ganymede and Callisto (see JUPITER: SATELLITES), orbit deep inside the magnetosphere of Jupiter (see JUPITER: MAGNETOSPHERE) and are therefore immersed in the flow of magnetospheric plasma (made of a mixture of electrons and ions) and subjected to an interaction with the strong Jovian magnetic field. These intera...

  13. [Theme Issue: Communications Satellites.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1976-01-01

    One section of this journal is devoted to issues involving broadcast satellites. Separate articles discuss the need for international planning of satellite broadcasting, decisions made at the 1971 World Administrative Radio Conference for Space Telecommunications, potential problems in satellite broadcasting, a series of proposals drawn up by the…

  14. Germany's Option for a Moon Satellite

    NASA Astrophysics Data System (ADS)

    Quantius, Dominik

    The German non-profit amateur satellite organisation AMSAT-Deutschland successfully de-signed, built and launched four HEO satellites in the last three decades. Now they are going to build a satellite to leave the Earth orbit based on their flight-proven P3-D satellite design. Due to energetic constraints the most suitable launch date for the planned P5-A satellite to Mars will be in 2018. To efficiently use the relatively long time gap until launch a possible prior Moon mission came into mind. In co-operation with the DLR-Institute of Space Systems in Bremen, Germany, two studies on systems level for a first P5 satellite towards Moon and a following one towards Mars have been performed. By using the DLR's Concurrent Engineering Facility (CEF) two consistent satellite concepts were designed including mission analysis, configuration, propulsion, subsystem dimensioning, payload selection, budgeting and cost. The present paper gives an insight in the accomplished design process and the results of the performed study towards Moon. The developed Moon orbiter is designed to carry the following four main instruments besides flexible communication abilities: • slewable HDTV camera combined with a high gain antenna that allows receiving lunar television using a commercially available satellite TV dish on Earth • sensor imaging infrared spectrometer for mineralogy of lunar silicates and lunar surface temperature measurements • camera for detection and monitoring of impact flashes in visible light (VIS) on lunar night side caused by meteoroid impact events • camera technology test for interplanetary navigation and planetary approach navigation. This study presents a non-industrial satellite concept that could be launched as piggyback load on Ariane 5 into GTO. Due to the fact, that the satellite would be built by the private sector, the mission costs would remain low. Otherwise the scientific and public output would be high using that satellite bus for the instruments

  15. Optimization of satellite constellation reconfiguration maneuvers

    NASA Astrophysics Data System (ADS)

    Appel, Leonid; Guelman, Moshe; Mishne, David

    2014-06-01

    Constellation satellites are required to perform orbital transfer maneuvers. Orbital transfer maneuvers, as opposed to orbital correction maneuvers, are seldom performed but require a substantial amount of propellant for each maneuver. The maneuvers are performed in order to obtain the desired constellation configuration that satisfies the coverage requirements. In most cases, the single-satellite position is immaterial; rather the relative position between constellation multiple-satellites is to be controlled. This work deals with the solution to the coupled optimization problem of multiple-satellite orbital transfer. The studied problem involves a coupled formulation of the terminal conditions of the satellites. The solution was achieved using functional optimization techniques by a combined algorithm. The combined algorithm is based on the First Order Gradient and Neighboring-Extremals Algorithms. An orbital transfer optimization tool was developed. This software has the ability to consider multiple satellites with coupled terminal conditions. A solution to the multiple-satellite orbital transfer optimization problem is presented. A comparison of this solution to the uncoupled case is presented in order to review the benefits of using this approach. It is concluded that the coupled transfer maneuver solution approach is more computationally efficient and more accurate. Numerical solutions for a number of representative cases are presented.

  16. A small terminal for satellite communication systems

    NASA Technical Reports Server (NTRS)

    Xiong, Fuqin; Wu, Dong; Jin, Min

    1994-01-01

    A small portable, low-cost satellite communications terminal system incorporating a modulator/demodulator and convolutional-Viterbi coder/decoder is described. Advances in signal processing and error-correction techniques in combination with higher power and higher frequencies aboard satellites allow for more efficient use of the space segment. This makes it possible to design small economical earth stations. The Advanced Communications Technology Satellite (ACTS) was chosen to test the system. ACTS, operating at the Ka band incorporates higher power, higher frequency, frequency and spatial reuse using spot beams and polarization.

  17. The sad saga of small satellites

    SciTech Connect

    Taubes, G.

    1993-02-12

    While the massive EOS program lumbers toward its first scheduled lauch in 1998, many global change variables are going unmonitored. So why not fill the gap with a separate program of simple, cheaper satellites to monitor such things as atmospheric aerosols, water vapor, clouds and the radiation budget Good idea, many NASA advisers have said. But a combination of NASA's reluctance and agency tug-of-wars seems likely to keep the small satellites grounded.

  18. Survey: National Environmental Satellite Service

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The national Environmental Satellite Service (NESS) receives data at periodic intervals from satellites of the Synchronous Meteorological Satellite/Geostationary Operational Environmental Satellite series and from the Improved TIROS (Television Infrared Observational Satellite) Operational Satellite. Within the conterminous United States, direct readout and processed products are distributed to users over facsimile networks from a central processing and data distribution facility. In addition, the NESS Satellite Field Stations analyze, interpret, and distribute processed geostationary satellite products to regional weather service activities.

  19. Fundamentals of satellite navigation

    NASA Astrophysics Data System (ADS)

    Stiller, A. H.

    The basic operating principles and capabilities of conventional and satellite-based navigation systems for air, sea, and land vehicles are reviewed and illustrated with diagrams. Consideration is given to autonomous onboard systems; systems based on visible or radio beacons; the Transit, Cicada, Navstar-GPS, and Glonass satellite systems; the physical laws and parameters of satellite motion; the definition of time in satellite systems; and the content of the demodulated GPS data signal. The GPS and Glonass data format frames are presented graphically, and tables listing the GPS and Glonass satellites, their technical characteristics, and the (past or scheduled) launch dates are provided.

  20. TSS Satellite Overview

    NASA Technical Reports Server (NTRS)

    Manarini, G.

    1985-01-01

    The responsibilities of NASA and PSN/CNR in the tethered satellite system cooperative program are listed and PSN/CNR-AIT system support and technologies studies are summarized. Results are given for investigations of active vs. passive satellite trade offs; analysis of alternative maneuvers; satellite attitude and position determination analysis failure modes analysis; moveable boom dynamic analysis; double tethered satellite system; and thermo/dynamic analysis for 100 km to 120 km altitude range. Objectives for the space plasma science mission and its applications are outlined and the TSS satellite configuration is highlighted. Programmatic aspects are included.

  1. Digital satellite communications

    NASA Astrophysics Data System (ADS)

    Ha, T. T.

    1986-06-01

    The use of satellite communications in point-to-multipoint transmission of data is studied. The theory, systems, and equipment for satellite communications are described. The topics of satellite orbits, satellite construction, earth station equipment, and the analysis of the satellite link are discussed. Different types of digital modulation for carrier transmission, and techniques for enhancing the transmission capacity, such as digital speech interpolation and demand assignment, are examined. Techniques and equipment for performing the multiple access-broadcasting functions including FDMA, TDMA, DAMA, CDMA, and random access are considered.

  2. Combined Summary Paper: -Current and Future Geodetic Satellite Mission for Global Change Monitoring - On the Capability of Swarm for Surface Mass Variation Monitoring: Quantitative Assessment Based on Orbit Information from CHAMP, GRACE, and GOCE - The Lake Level Variations in China from Satellite Altimetric Data

    NASA Astrophysics Data System (ADS)

    Sneeuw, N.; Li, J.; Baur, O.; Cai, J.; Tourian, M. J.; Elmi, O.; Jiang, W.; Chu, Y.; Jin, T.; Wirnsberger, H.; Krauss, S.; Maier, A.

    2014-11-01

    Global change deals with large- and small-scale processes that modify the Earth’s atmosphere, land and ocean. Using innovative geodetic space-borne sensor systems, dedicated gravity field and altimeter satellites monitor these processes over a range of spatial and temporal scales. The integrated analysis of these geometric and gravimetric Earth observation data shall improve the knowledge of system processes of the changing Earth. A few case studies elucidate the role of satellite geodesy in Earth system science. These following two just link to later in the table of contents and don't have actual papers attached to them.

  3. Evolution of Extended Satellites in Massive Halos

    NASA Astrophysics Data System (ADS)

    Gravel, Pierre

    The evolution of extended satellites in massive halos is studied in the weak and the strong regimes of satellite deformation. In the first part of the thesis we follow the dynamics of a spherical region evolving locally as an Einstein-de Sitter universe ( qo=0.5,W=1 ) and containing overdensities acting as seeds for the formation of a satellite and its future host. We study the dynamics of forming satellites when their hosts are still unvirialized, accreting material, and generating time-varying gravitational potentials (TVGP). The three main dynamical processes affecting the satellite are dynamical friction, the TVGP, and tidal disruption. The internal flow of energy inside a satellite and across its boundary is analyzed with specialized local and global methods, providing information on the nature, the magnitude and the timing of the individual processes. A strongly deformed satellite able to survive a few galaxy crossings forms a compact core from which dynamical friction extracts energy, while its halo is tidally disrupted by the ``slingshot'' effect. This leads to the formation of systems of external stellar shells and internal energy shells. Their origins and appearances are closely related. Satellite self-gravity and phase wrapping control the emergence of both types of shells from the satellite inner regions once non-linear effects set in. In the second part of the thesis, we analyze the combined effects of dynamical friction, tidal stripping, and internal and external two-body heating on satellites moving inside massive hosts. External two-body heating is a stochastic process that occurs inside a satellite as a back reaction to the scattering of inhomogeneous material in the surrounding stellar system. This type of heating accelerates the evolution of less bound objects by increasing their rate of evaporation. The heating becomes important at low satellite velocities, and when the masses of the perturbing objects are comparable to or greater than the

  4. Satellite altitude determination uncertainties

    NASA Technical Reports Server (NTRS)

    Siry, J. W.

    1971-01-01

    Satellite altitude determination uncertainties are discussed from the standpoint of the GEOS-C satellite. GEOS-C will be tracked by a number of the conventional satellite tracking systems, as well as by two advanced systems; a satellite-to-satellite tracking system and lasers capable of decimeter accuracies which are being developed in connection with the Goddard Earth and Ocean Dynamics Applications program. The discussion is organized in terms of a specific type of GEOS-C orbit which would satisfy a number of scientific objectives including the study of the gravitational field by means of both the altimeter and the satellite-to-satellite tracking system, studies of tides, and the Gulf Stream meanders.

  5. The Study and Applications of Satellite and Satellite Constellation Autonomous Orbit Determination Using Star Sensor

    NASA Astrophysics Data System (ADS)

    Gan, Q. B.

    2012-07-01

    Autonomous satellite orbit determination is a key technique in autonomous satellite navigation. Many kinds of technologies have been proposed to realize the autonomous satellite navigation, such as the star sensor, the Earth magnetometer, the occultation time survey, and the phase measurement of X-ray pulsar signals. This dissertation studies a method of autonomous satellite orbit determination using star sensor. Moreover, the method is extended to the autonomous navigation of satellite constellation and the space-based surveillance. In chapters 1 and 2, some usual time and reference systems are introduced. Then the principles of several typical autonomous navigation methods, and their merits and shortcomings are analyzed. In chapter 3, the autonomous satellite orbit determination using star sensor and infrared Earth sensor (IRES) is specifically studied, which is based on the status movement simulation, the stellar background observation from star sensor, and the Earth center direction survey from IRES. By simulating the low Earth orbit satellites and pseudo Geostationary Earth orbit (PGEO) satellites, the precision of position and speed with autonomous orbit determination using star sensor is obtained. Besides, the autonomous orbit determination using star sensor with double detectors is studied. According to the observation equation's characters, an optimized type of star sensor and IRES initial assembly model is proposed. In the study of the PGEO autonomous orbit determination, an efficient sampling frequency of measurements is promoted. The simulation results confirm that the autonomous satellite orbit determination using star sensor is feasible for satellites with all kinds of altitudes. In chapter 4, the method of autonomous satellite orbit determination using star sensor is extended to the autonomous navigation of mini-satellite constellation. Combining with the high-accuracy inter satellite links data, the precision of the determined orbit and

  6. Ephemeris errors of GPS satellites

    NASA Technical Reports Server (NTRS)

    Colombo, O. L.

    1986-01-01

    Numerical models are developed to examine the potential effects of solar radiation, the terrestrial gravitational field, and the estimated initial state of the Global Positioning System (GPS) satellites, along with the capability of current models to account for the effects on the ephemeris of the GPS constellation. Of particular interest is the accuracy of the satellite position predictions for applications in geodesy. The main characteristics of the GPS orbits are reviewed and linear combinations of possible errors for 3 day ephemerides are examined. It is shown that the effects of the forces on the GPS orbits will be dynamic, yet can be expressed simply enough to maintain positioning accuracy to 1 percent. The calculations can also take into consideration solar wind pressure on the solar panels.

  7. Communication satellite applications

    NASA Astrophysics Data System (ADS)

    Pelton, Joseph N.

    The status and future of the technologies, numbers and services provided by communications satellites worldwide are explored. The evolution of Intelsat satellites and the associated earth terminals toward high-rate all-digital telephony, data, facsimile, videophone, videoconferencing and DBS capabilities are described. The capabilities, services and usage of the Intersputnik, Eutelsat, Arabsat and Palapa systems are also outlined. Domestic satellite communications by means of the Molniya, ANIK, Olympus, Intelsat and Palapa spacecraft are outlined, noting the fast growth of the market and the growing number of different satellite manufacturers. The technical, economic and service definition issues surrounding DBS systems are discussed, along with presently operating and planned maritime and aeronautical communications and positioning systems. Features of search and rescue and tracking, data, and relay satellite systems are summarized, and services offered or which will be offered by every existing or planned communication satellite worldwide are tabulated.

  8. Satellite services system overview

    NASA Technical Reports Server (NTRS)

    Rysavy, G.

    1982-01-01

    The benefits of a satellite services system and the basic needs of the Space Transportation System to have improved satellite service capability are identified. Specific required servicing equipment are discussed in terms of their technology development status and their operative functions. Concepts include maneuverable television systems, extravehicular maneuvering unit, orbiter exterior lighting, satellite holding and positioning aid, fluid transfer equipment, end effectors for the remote manipulator system, teleoperator maneuvering system, and hand and power tools.

  9. Satellite Antenna Systems

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Through the Technology Affiliates Program at the Jet Propulsion Laboratory, the ACTS antenna system was transferred from experimental testing status to commercial development with KVH Industries, Inc. The ACTS design enables mobile satellite antennas to remain pointed at the satellite, regardless of the motion or vibration on which it is mounted. KVH's first product based on the ACTS design is a land-mobile satellite antenna system that will enable direct broadcast satellite television aboard moving trucks, recreational vehicles, trains, and buses. Future products could include use in broadcasting, emergency medical and military vehicles.

  10. Methods of satellite oceanography

    NASA Technical Reports Server (NTRS)

    Stewart, R. H.

    1985-01-01

    The theoretical basis for remote sensing measurements of climate and ocean dynamics is examined. Consideration is given to: the absorption of electromagnetic radiation in the atmosphere; scattering in the atmosphere; and satellite observations using visible light. Consideration is also given to: the theory of radio scatter from the sea; scatter of centimeter waves from the sea; and the theory of operation of synthetic aperture radars. Additional topics include: the coordinate systems of satellite orbits for oceanographic remote sensing applications; the operating features of the major U.S. satellite systems for viewing the ocean; and satellite altimetry.

  11. Satellite Tracking System

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Researchers at the Center for Aerospace Sciences of the University of North Dakota (UND), Grand Forks, used three NASA Computer programs (SANDTRACKS, ODG, NORAD) to develop a Satellite Tracking System for real time utilization of TIROS weather/environment satellite information. SANDTRACKS computes the satellite's position relative to the Earth. ODG allows plotting a view of Earth as seen by the satellite. NORAD computes sight direction, visibility times and maximum elevation angle during each orbit. With the system, UND's Earth System Science Institute will be able to routinely monitor agricultural and environmental conditions of the Northern Plains.

  12. Satellite networks for education

    NASA Technical Reports Server (NTRS)

    Singh, J. P.; Morgan, R. P.; Rosenbaum, F. J.

    1972-01-01

    Satellite based educational networking is discussed with particular attention given to the potential uses of communications satellites to help meet educational needs in the United states. Four major subject areas were covered; (1) characteristics and structure of networks, (2) definition of pressures within educational establishment that provide motivation for various types of networks, (3) examination of current educational networking status for educational radio and television, instructional television fixed services, inter- and intra-state educational communication networks, computer networks, and cable television for education, and (4) identification of possible satellite based educational telecommunication services and three alternatives for implementing educational satellite systems.

  13. Satellite communication antenna technology

    NASA Technical Reports Server (NTRS)

    Mittra, R. (Editor); Imbriale, W. A. (Editor); Maanders, E. J. (Editor)

    1983-01-01

    A general overview of current technology in the field of communication satellite antennas is presented. Among the topics discussed are: the design of multiple beam systems; frequency reuse; and polarization control of antenna measurements. Consideration is also given to: contour beam synthesis; dual shaped reflector synthesis; beam shaping; and offset reflector design. The applications of the above technologies to present and future generations of communications satellites is considered, with emphasis given to such systems as: the Intelsats; the Defense Satellite Communications System, (DSCS-III); Satellite Business System (SBS), and Comstar.

  14. Future satellite systems - Market demand assessment

    NASA Technical Reports Server (NTRS)

    Reiner, P. S.

    1981-01-01

    During 1979-80, a market study was performed regarding the future total demand for communications services, and satellite transmission service at the 4/6 GHz, 12/14 GHz, and 20/30 GHz frequencies. Included in the study were a variety of communications traffic characteristics as well as projections of the cost of C and Ku band satellite systems through the year 2000. In connection with the considered study, a total of 15 major study tasks and subtasks were undertaken and were all interrelated in various ways. The telecommunications service forecasts were concerned with a total of 21 data services, 5 voice services, and 5 video services. The traffic volumes within the U.S. for the three basic services were projected for three time periods. It is found that the fixed frequency allocation for domestic satellites combined with potential interference from adjacent satellites means a near term lack of orbital positions above the U.S.

  15. Global satellite composites - 20 years of evolution

    NASA Astrophysics Data System (ADS)

    Kohrs, Richard A.; Lazzara, Matthew A.; Robaidek, Jerrold O.; Santek, David A.; Knuth, Shelley L.

    2014-01-01

    For two decades, the University of Wisconsin Space Science and Engineering Center (SSEC) and the Antarctic Meteorological Research Center (AMRC) have been creating global, regional and hemispheric satellite composites. These composites have proven useful in research, operational forecasting, commercial applications and educational outreach. Using the Man computer Interactive Data System (McIDAS) software developed at SSEC, infrared window composites were created by combining Geostationary Operational Environmental Satellite (GOES), and polar orbiting data from the SSEC Data Center and polar data acquired at McMurdo and Palmer stations, Antarctica. Increased computer processing speed has allowed for more advanced algorithms to address the decision making process for co-located pixels. The algorithms have evolved from a simplistic maximum brightness temperature to those that account for distance from the sub-satellite point, parallax displacement, pixel time and resolution. The composites are the state-of-the-art means for merging/mosaicking satellite imagery.

  16. Processing of satellite imagery at the National Environmental Satellite Service

    NASA Technical Reports Server (NTRS)

    Crowe, M.

    1977-01-01

    The National Environmental Satellite Service (NESS) image product processing system is described. Other topics discussed include: (1) image processing of polar-orbiter satellite data; (2) image processing of geostationary satellite data; and (3) quality assurance and product monitoring.

  17. Amateur Radio Satellite Communications.

    ERIC Educational Resources Information Center

    Koch, David P.

    The Amateur Radio Satellite Communications project had, as its goal, the assembly of an amateur radio satellite station in a high school physics classroom. Specific objectives were to provide: (1) a special source of interest as a motivator for attracting students and building public relations; (2) a center of interest as a motivator for the study…

  18. Satellite Teleconference Final Report.

    ERIC Educational Resources Information Center

    Elgin Community Coll., IL.

    The vocational education satellite teleconference project accomplished two goals: (1) identified, acquired, copied, and distributed to the Illinois Vocational Curriculum Center 100 marketing or training videotapes for staff development and classroom use; and (2) provided from 15-25 variable time (1- to 3-hour) satellite teleconferences in four…

  19. Audio direct broadcast satellites

    NASA Technical Reports Server (NTRS)

    Miller, J. E.

    1983-01-01

    Satellite sound broadcasting is, as the name implies, the use of satellite techniques and technology to broadcast directly from space to low-cost, consumer-quality receivers the types of sound programs commonly received in the AM and FM broadcast bands. It would be a ubiquitous service available to the general public in the home, in the car, and out in the open.

  20. Advanced communications satellites

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1980-01-01

    The increase in demand for satellite communications services brought about shortages in available transponder capacity, especially at C-band. Interest shifted to the Ku-band frequency and currently carriers are rapidly moving to secure orbital slots for future satellite development. Projections of communications service demands over the next decade indiate growth in voice, data, and video services such that saturation of both C-band and Ku-band will occur by 1990. Emphasis must and will shift to Ka-band (20/30 GHz) frequency for fixed-satellite service. Advanced technologies such as multibeam antennas coupled with on-board satellite switching to allow implementation in this band of very high capacity satellite systems will be applied to meet the demand. Satellite system concepts that are likely in the 1990's and are likely to bring a new dimension to satellite delivered communication service are presented. The NASA 30/20 GHz communications satellite system demonstration program is discussed with emphasis on the related technology development.

  1. Laser Geodynamics Satellite I

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The LAGEOS I (Laser Geodynamics Satellite) was developed and launched by the Marshall Space Flight Center on May 4, 1976 from Vandenberg Air Force Base, California . The two-foot diameter satellite orbited the Earth from pole to pole and measured the movements of the Earth's surface.

  2. Outer planets satellites

    NASA Technical Reports Server (NTRS)

    Morrison, D.

    1983-01-01

    The present investigation takes into account the published literature on outer planet satellites for 1979-1982. It is pointed out that all but three (the moon and the two Martian satellites) of the known planetary satellites are found in the outer solar system. Most of these are associated with the three regular satellite systems of Jupiter, Saturn, and Uranus. The largest satellites are Titan in the Saturn system and Ganymede and Callisto in the Jupiter system. Intermediate in size between Mercury and Mars, each has a diameter of about 5000 km. Presumably each has an internal composition about 60 percent rock and 40 ice, and each is differentiated with a dense core extending out about 75 percent of the distance to the surface, with a mantle of high-pressure ice and a crust of ordinary ice perhaps 100 km thick. Attention is also given to Io, Europa, the icy satellites of Saturn, the satellites of Uranus, the small satellites of Jupiter and Saturn, Triton and the Pluto system, and plans for future studies.

  3. Communication satellite technology trends

    NASA Technical Reports Server (NTRS)

    Cuccia, Louis

    1986-01-01

    A chronology of space-Earth interconnectivity is presented. The Advanced Communications Technology Satellite (ACTS) system, Land Mobile Satellite, space-Earth antennas, impact of antenna size on coverage, intersatellite links are outlined. This presentation is represented by graphs and charts only.

  4. Communications technology satellite

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A description of the Communications Technology Satellite (CTS), its planned orbit, its experiments, and associated ground facilities was given. The communication experiments, to be carried out by a variety of groups in both the United States and Canada, include tele-education, tele-medicine, community interaction, data communications and broadcasting. A historical summary of communications satellite development was also included.

  5. Satellites in Schools.

    ERIC Educational Resources Information Center

    Underwood, C. I.; And Others

    1987-01-01

    Discusses the use of satellite data in physics classrooms. Describes the apparatus that can be used to collect and analyze data. Provides examples of how telemetry data transmitted by the satellite UoSAT-2 can be used not only in teaching physics, but also in geography, mathematics, and information technology. (TW)

  6. Telecommunications satellite systems

    NASA Astrophysics Data System (ADS)

    Ramat, Pierre

    1992-12-01

    A survey of the telecommunications satellite field is presented. After a review of the historical and regulatory background, the main technical features of satellite networks are analyzed, and existing international and national systems are considered. Particular attention is given to Intelsat, Inmarsat, Eutelsat, and Telecom 1 and 2. Future technical and economic trends are then projected.

  7. Signals from Communications Satellites.

    ERIC Educational Resources Information Center

    Thomsen, Volker

    1996-01-01

    Discusses the Doppler effect for relative motion between a source of waves and an observer and the orbital dynamics of communications satellites. Presents preliminary calculations of the satellite's altitude and linear velocity using only the concepts of the Doppler shift and the mechanics of motion in a circular path. (JRH)

  8. The Satellite Situation Center

    NASA Technical Reports Server (NTRS)

    Teague, M. J.; Sawyer, D. M.; Vette, J. I.

    1982-01-01

    Considerations related to the early planning for the International Magnetospheric Study (IMS) took into account the desirability of an establishment of specific entities for generating and disseminating coordination information for both retrospective and predictive periods. The organizations established include the IMS/Satellite Situation Center (IMS/SSC) operated by NASA. The activities of the SSC are related to the preparation of reports on predicted and actually achieved satellite positions, the response to inquiries, the compilation of information on satellite experiments, and the issue of periodic status summaries. Attention is given to high-altitude satellite services, other correlative satellite services, non-IMS activities of the SSC, a summary of the SSC request activity, and post-IMS and future activities.

  9. Satellite networks for education.

    NASA Technical Reports Server (NTRS)

    Singh, J. P.; Morgan, R. P.; Rosenbaum, F. J.

    1972-01-01

    Consideration of satellite-based educational networking. The characteristics and structure of networks are reviewed, and pressures within the educational establishment that are providing motivation for various types of networks are discussed. A number of studies are cited in which networking needs for educational sectors and services are defined. The current status of educational networking for educational radio and television, instructional television fixed services, inter- and intrastate educational communication networks, computer networks, cable television for education, and continuing and proposed educational experiments using NASA's Applications Technology Satellites is reviewed. Possible satellite-based educational telecommunication services and three alternatives for implementing educational satellite systems are described. Some remarks are made concerning public policy aspects of future educational satellite system development.

  10. Pastures from Space: What can we learn from satellite images?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Satellites such as the Landsat platform record both visible light and near infrared radiation. These can be combined to produce estimates of standing plant biomass. Satellite estimates of plant production have been widely used in rangelands and forests where large areas are studied. The square Lands...