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Sample records for airborne ionospheric observatory

  1. Optical instrumentation support for the airborne ionospheric observatory. Report for 1 July 1987-30 June 1988

    SciTech Connect

    Eather, R.H.; Lance, C.A.

    1988-07-01

    The objectives were to participate in ionospheric research programs using the new optical equipment that was planned to be installed on the Airborne Ionospheric Observatory (AIO), a research aircraft operated by the Ionospheric Effects Branch at AFGL. This participation was to include: (a) testing, improvement, and continuing development of the software operating systems that control the instrument operation, (b) Complete testing, calibration, and documentation of all optical properties of the optical systems, (c) Improvements and continuing development of data recording systems for all instruments, and techniques for quick-look data presentation, (d) Assistance in analysis of optical data obtained on airglow and auroral experiments, and (e) Provide personnel assistance on research flights and field trips as required by AFGL.

  2. 10 meter airborne observatory

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.; Ritter, Joseph M.

    2008-07-01

    Inside an aircraft fuselage there is little room for the mass of all the instrumentation of a ground-based observatory much less a primary objective aperture at the scale of 10 meters. We have proposed a solution that uses a primary objective grating (POG) which matches the considerable length of the aircraft, approximately 10 meters, and conforms to aircraft aerodynamics. Light collected by the POG is diffracted at an angle of grazing exodus inside the aircraft where it is disambiguated by an optical train that fits within to the interior tunnel. Inside the aircraft, light is focused by a parabolic mirror onto a spectrograph slit. The design has a special benefit in that all objects in the field-of-view of the free spectral range of the POG can have their spectra taken as the aircraft changes orientation. We suggest flight planes that will improve integration times, angular resolution and spectral resolution to acquire targets of high stellar magnitudes or alternatively increase the number of sources acquired per flight at the cost of sensitivity.

  3. The Livingston Island Geomagnetic and Ionospheric Observatory

    NASA Astrophysics Data System (ADS)

    Altadill, David; Marsal, Santiago; Blanch, Estefania; Miquel Torta, J.; Quintana-Seguí, Pere; Germán Solé, J.; Cid, Òscar; José Curto, Juan; Ibáñez, Miguel; Segarra, Antoni; Lluís Pijoan, Joan; Juan, Juan Miguel

    2014-05-01

    The Ebre Observatory Institute manages a geophysical observatory installed at the Spanish Antarctic Station (SAS) Juan Carlos I. It was set up in 1995 and it has been updated yearly by our team throughout several projects carried out since then. Nowadays, it hosts a magnetic station providing 1-second data of the 3 components (X, Y, Z) and the total force (F) during the entire year, and an ionospheric station providing vertical and oblique data during austral summer. This observatory has provided long data series of high scientific value from this remote region of the Earth. They have been used to improve the knowledge of the climate and weather behavior of the geomagnetic field and ionosphere in the area, and to model and expand the capacity of data transmission. This contribution aims to present a brief review of the instruments installed at SAS, the research results obtained from their data, and the developing activities under the current project. Finally, future perspectives are outlined with regard to adapting our geophysical observatory to the evolving needs of observatory practice.

  4. Molecular spectroscopy from the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Beckwith, S.

    1985-01-01

    Interstellar and circumstellar molecules are investigated through medium-resolution infrared spectrosocpy of the vibration-rotation and pure rotational transitions. A primary goal was the construction and improvement of instrumentation for the near and middle infrared regions, wavelengths between 2 and 10 microns. The main instrument was a cooled grating spectrometer with an interchangeable detector focal plane which could be used on the Kuiper Airborne Observatory (KAO) for airborne observations, and also at ground-based facilities. Interstellar shock waves were investigated by H2 emission from the Orion Nebula, W51, and the proto-planetary nebulae CRL 2688 and CRL 618. The observations determined the physical conditions in shocked molecular gas near these objects. From these it was possible to characterize the energetic history of mass loss from both pre- and post-main sequence stars in the regions.

  5. NASA’s Sense of Snow: the Airborne Snow Observatory

    NASA Video Gallery

    Water is a critical resource in the western U.S. NASA’s Airborne Snow Observatory is giving California water agencies the first complete measurements of the water available in the Sierra snowpack ...

  6. SOFIA's Choice: Scheduling Observations for an Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy; Kurklu, Elif; Koga, Dennis (Technical Monitor)

    2002-01-01

    We describe the problem of scheduling observations for an airborne observatory. The problem is more complex than traditional scheduling problems in that it incorporates complex constraints relating the feasibility of an astronomical observation to the position and time of a mobile observatory, as well as traditional temporal constraints and optimization criteria. We describe the problem, its proposed solution and the empirical validation of that solution.

  7. Far-Infrared Astronomy with The Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Hildebrand, Roger, H.

    1997-01-01

    This report summarizes work made possible by NASA's Kuiper Airborne Observatory. The results of the work have appeared in over 80 papers. The publications fall in three main areas: instrumentation, observations, and analysis. Although there is considerable overlap between these categories it will be convenient to group them separately.

  8. Comprehension and retrieval of failure cases in airborne observatories

    NASA Technical Reports Server (NTRS)

    Alvarado, Sergio J.; Mock, Kenrick J.

    1995-01-01

    This paper describes research dealing with the computational problem of analyzing and repairing failures of electronic and mechanical systems of telescopes in NASA's airborne observatories, such as KAO (Kuiper Airborne Observatory) and SOFIA (Stratospheric Observatory for Infrared Astronomy). The research has resulted in the development of an experimental system that acquires knowledge of failure analysis from input text, and answers questions regarding failure detection and correction. The system's design builds upon previous work on text comprehension and question answering, including: knowledge representation for conceptual analysis of failure descriptions, strategies for mapping natural language into conceptual representations, case-based reasoning strategies for memory organization and indexing, and strategies for memory search and retrieval. These techniques have been combined into a model that accounts for: (a) how to build a knowledge base of system failures and repair procedures from descriptions that appear in telescope-operators' logbooks and FMEA (failure modes and effects analysis) manuals; and (b) how to use that knowledge base to search and retrieve answers to questions about causes and effects of failures, as well as diagnosis and repair procedures. This model has been implemented in FANSYS (Failure ANalysis SYStem), a prototype text comprehension and question answering program for failure analysis.

  9. Analysis of Polarization Data from the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Hildebrand, Roger H.

    1999-01-01

    The purpose of this grant was to complete the analysis of data obtained with the polarimeter, Hertz, on the Kuiper Airborne Observatory. This has enabled us to complete and publish two student theses (one on Sgr B2 and one on Orion) and a paper on the first results on the far-infrared polarization-spectrum. In addition it has enabled us to analyze data for two additional papers (one on W3 and the other a complete archive of KAO polarization data) which have reached the stage of complete drafts but still need checking and editing before final submission.

  10. Calibration of the National Ecological Observatory Network's Airborne Imaging Spectrometers

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    The National Ecological Observatory Network (NEON) is currently under construction by the National Science Foundation. NEON is designed to collect data on the causes and responses to change in the observed ecosystem. The observatory will combine site data collected by terrestrial, instrumental, and aquatic observation systems with airborne remote sensing data. The Airborne Observation Platform (AOP) is designed to collect high-resolution aerial imagery, waveform and discrete LiDAR, and high-fidelity imaging spectroscopic data over the NEON sites annually at or near peak-greenness. Three individual airborne sensor packages will be installed in leased Twin Otter aircraft and used to the collect the NEON sites as NEON enters operations. A key driver to the derived remote sensing data products is the calibration of the imaging spectrometers. This is essential to the overall NEON mission to detect changes in the collected ecosystems over the 30-year expected lifetime. The NEON Imaging Spectrometer (NIS) is a Visible and Shortwave Infrared (VSWIR) grating spectrometer designed by NASA JPL. Spectroscopic data is collected at 5-nm intervals from 380-2500-nm. A single 480 by 640 pixel HgCdTe Focal Plane Array collects dispersed light from a grating tuned for efficiency across the solar-reflective utilized in a push-broom configuration. Primary calibration of the NIS consists of the characterizing the FPA behavior, spectral calibration, and radiometric calibration. To this end, NEON is constructing a Sensor Test Facility to calibrate the NEON sensors. This work discusses the initial NIS laboratory calibration and verification using vicarious calibration techniques during operations. Laboratory spectral calibration is based on well-defined emission lines in conjunction with a scanning monochromator to define the individual spectral response functions. A NIST traceable FEL bulb is used to radiometrically calibrate the imaging spectrometer. An On-board Calibration (OBC) system

  11. The study of the midlatitude ionospheric response to geomagnetic activity at Nagycenk Geophysical Observatory

    NASA Astrophysics Data System (ADS)

    Berényi, Kitti; Kis, Árpád; Barta, Veronika; Novák, Attila

    2016-04-01

    Geomagnetic storms affect the ionospheric regions of the terrestrial upper atmosphere, causing several physical and chemical atmospheric processes. The changes and phenomena, which can be seen as a result of these processes, generally called ionospheric storm. These processes depend on altitude, term of the day, and the strength of solar activity, the geomagnetic latitude and longitude. The differences between ionospheric regions mostly come from the variations of altitude dependent neutral and ionized atmospheric components, and from the physical parameters of solar radiation. We examined the data of the ground-based radio wave ionosphere sounding instruments of the European ionospheric stations (mainly the data of Nagycenk Geophysical Observatory), called ionosonde, to determine how and what extent a given strength of a geomagnetic disturbance affect the middle latitude ionospheric regions in winter. We chose the storm for the research from November 2012 and March 2015. As the main result of our research, we can show significant differences between the each ionospheric (F1 and F2) layer parameters on quiet and strong stormy days. When we saw, that the critical frequencies (foF2) increase from their quiet day value, then the effect of the ionospheric storm was positive, otherwise, if they drop, they were negative. With our analysis, the magnitude of these changes could be determined. Furthermore we demonstrated, how a full strong geomagnetic storm affects the ionospheric foF2 parameter during different storm phases. It has been showed, how a positive or negative ionospheric storm develop during a geomagnetic storm. For a more completed analysis, we compared also the evolution of the F2 layer parameters of the European ionosonde stations on a North-South geographic longitude during a full storm duration. Therefore we determined, that the data of the ionosonde at Nagycenk Geophysical Observatory are appropriate, it detects the same state of ionosphere like the

  12. Description and catalog of ionospheric F-region data, Jicamarca Radar Observatory, November 1966 - April 1969

    NASA Technical Reports Server (NTRS)

    Clark, W. L.; Mcclure, J. P.; Vanzandt, T. E.

    1976-01-01

    Equatorial ionospheric F-region data reduced from the Jicamarca Radar Observatory (JRO) incoherent scatter observations for particular periods is described. It lists in catalog form the times of the observations made during those periods. These F-region data include the electron concentration and the electron and ion temperatures. The data were inferred from the incoherent scatter observations of JRO.

  13. Symmetry and asymmetry of ionospheric weather at magnetic conjugate points for two midlatitude observatories

    NASA Astrophysics Data System (ADS)

    Gulyaeva, T. L.; Arikan, F.; Stanislawska, I.; Poustovalova, L. V.

    2013-11-01

    Variations of the ionospheric weather W-index for two midlatitude observatories, namely, Grahamstown and Hermanus, and their conjugate counterpart locations in Africa are studied for a period from October 2010 to December 2011. The observatories are located in the longitude sector, which has consistent magnetic equator and geographic equator so that geomagnetic latitudes of the line of force are very close to the corresponding geographic latitudes providing opportunity to ignore the impact of the difference of the gravitational field and the geomagnetic field at the conjugate points on the ionosphere structure and dynamics. The ionosondes of Grahamstown and Hermanus provide data of the critical frequency (foF2), and Global Ionospheric Maps (GIM) provide the total electron content (TECgps) along the magnetic field line up to the conjugate point in the opposite hemisphere. The global model of the ionosphere, International Reference Ionosphere, extended to the plasmasphere altitude of 20,200 km (IRI-Plas) is used to deliver the F2 layer peak parameters from TECgps at the magnetic conjugate area. The evidence is obtained that the electron gas heated by day and cooled by night at the summer hemisphere as compared with the opposite features in the conjugate winter hemisphere testifies on a reversal of plasma fluxes along the magnetic field line by the solar terminator. The ionospheric weather W-index is derived from NmF2 (related with foF2) and TECgps data. It is found that symmetry of W-index behavior in the magnetic conjugate hemispheres is dominant for the equinoxes when plasma movement along the magnetic line of force is imposed on symmetrical background electron density and electron content. Asymmetry of the ionospheric storm effects is observed for solstices when the plasma diffuse down more slowly into the colder winter hemisphere than into the warmer summer hemisphere inducing either plasma increase (positive phase) or decrease (negative phase of W-index) in the

  14. Global Ultra-Violet Ionosphere-Thermosphere Observatory (GUVITO)

    NASA Astrophysics Data System (ADS)

    Curtis, N.; Crowley, G.; Christensen, A. B.; Paxton, L. J.; Robichaud, J.; Barry, M. A.; Bust, G. S.

    2009-12-01

    UV spectrographic imagers such as SSUSI and GUVI provide measurements of the aurora, ionospheric electron density, ionospheric bubbles, and thermospheric temperature, composition, and density. These imagers have been a key element of the Air Force DMSP program, but to accommodate new satellite concepts and maintain flexibility in the choice of new space systems and launch options, lighter weight and more capable UV instruments are needed to replace the current series of SSUSI sensors. Here we describe a technological alternative to the currently flying SSUSI sensors. It is a spectrographic imaging capability known as the “Global Ultra-Violet Ionosphere-Thermosphere Observatory” (GUVITO) sensor and associated software. GUVITO improves upon current instruments by being smaller in size, weight and power but with improved functionality. The GUVITO sensor represents an upgrade of the SSUSI and GUVI sensors in terms of scan mirror functionality and reliability, sensor functionality, mass, and power requirements. In particular, this improved functionality is expected to lead to enhanced capability in observing ionospheric bubbles, which are thought to cause scintillation and serious technological challenges for communications, navigation and surveillance systems. Initial development and risk reduction activities are currently funded by AFRL through a SBIR Phase II contract. The enhanced reliability and performance of the GUVITO sensor system is achieved with flight heritage components, concepts, software, hardware and is guided by key personnel experienced with both the SSUSI and GUVI hardware, software and operations. GUVITO would meet DoD priority requirements in ionospheric density, scintillation, and satellite drag, meet NPOESS IORD-II requirements for space environment Environmental Data Records (EDRs), maintain current DMSP capability, ensure long-term continuity of space environmental monitoring and leverage new technology development for future operational

  15. Automated Long - Term Scheduling for the SOFIA Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Civeit, Thomas

    2013-01-01

    The NASA Stratospheric Observatory for Infrared Astronomy (SOFIA) is a joint US/German project to develop and operate a gyro-stabilized 2.5-meter telescope in a Boeing 747SP. SOFIA's first science observations were made in December 2010. During 2011, SOFIA accomplished 30 flights in the "Early Science" program as well as a deployment to Germany. The new observing period, known as Cycle 1, is scheduled to begin in 2012. It includes 46 science flights grouped in four multi-week observing campaigns spread through a 13-month span. Automation of the flight scheduling process offers a major challenge to the SOFIA mission operations. First because it is needed to mitigate its relatively high cost per unit observing time compared to space-borne missions. Second because automated scheduling techniques available for ground-based and space-based telescopes are inappropriate for an airborne observatory. Although serious attempts have been made in the past to solve part of the problem, until recently mission operations staff was still manually scheduling flights. We present in this paper a new automated solution for generating SOFIA long-term schedules that will be used in operations from the Cycle 1 observing period. We describe the constraints that should be satisfied to solve the SOFIA scheduling problem in the context of real operations. We establish key formulas required to efficiently calculate the aircraft course over ground when evaluating flight schedules. We describe the foundations of the SOFIA long-term scheduler, the constraint representation, and the random search based algorithm that generates observation and instrument schedules. Finally, we report on how the new long-term scheduler has been used in operations to date.

  16. Automated long-term scheduling for the SOFIA airborne observatory

    NASA Astrophysics Data System (ADS)

    Civeit, Thomas

    The NASA Stratospheric Observatory for Infrared Astronomy (SOFIA) is a joint US/German project to develop and operate a gyro-stabilized 2.5-meter telescope in a Boeing 747SP. SOFIA's first science observations were made in December 2010. During 2011, SOFIA accomplished 30 flights in the “ Early Science” program as well as a deployment to Germany. The next observing period, known as Cycle 1, is scheduled to begin in late fall 2012. It includes 46 science flights grouped in four multi-week observing campaigns spread through a 13-month span. Automation of the flight scheduling process offers a major challenge to the SOFIA mission operations. First because it is needed to mitigate its relatively high cost per unit observing time compared to space-borne missions. Second because automated scheduling techniques available for ground-based and space-based telescopes are inappropriate for an airborne observatory. Although serious attempts have been made in the past to solve part of the problem, until recently mission operations staff was still manually scheduling flights. We present in this paper a new automated solution for generating SOFIA's long-term schedules. We describe the constraints that should be satisfied to solve the SOFIA scheduling problem in the context of real operations. We establish key formulas required to efficiently calculate the aircraft course over ground when evaluating flight schedules. We describe the foundations of the SOFIA long-term scheduler, the constraint representation, and the random search based algorithm that generates observation and instrument schedules. Finally, we report on how the new long-term scheduler has been used in operations to date.

  17. Comparison of ionospheric parameters calculated with UAM and measured at Voeykovo observatory

    NASA Astrophysics Data System (ADS)

    Rybakov, M. V.; Namgaladze, A. A.; Karpov, M. I.

    2016-09-01

    The measurements of the critical frequencies of the ionospheric F2 layer based on vertical radiosounding, which was performed with a CADI digital ionosonde at the Voeykovo magnetic-ionospheric observatory in February 2013, have been considered. The observations have been compared with the upper atmosphere numerical model (UAM) data for three days that differ in the amplitude and the character of solar and magnetic activity and correspond to quiet and moderately disturbed states of the ionosphere. The work was performed in order to improve the methods for determining the ionospheric state by vertical sounding ionograms. The time variations in the F2 layer critical frequency, electric field vector zonal component, and thermospheric wind velocity meridional component have been analyzed. Calculations were performed with three UAM variants. The UAM version providing the best agreement with the CADI ionosonde data was the version in which the neutral temperature, neutral composition, and pressure gradients are calculated according to the MSIS empirical model and the horizontal neutral wind velocity is determined by the equation of motion with pressure gradients from MSIS. The calculated values corresponded to the measurements, except those for the evening, because the electron density at the ionospheric F2 layer maximum depends more strongly on electric fields and thermospheric wind velocities during this period. Thus, the indicated UAM version with the above limitations can be used to determine the state of the subauroral ionosphere.

  18. The NASA Airborne Snow Observatory: Demonstration Mission 2

    NASA Astrophysics Data System (ADS)

    Painter, T. H.; Berisford, D. F.; Boardman, J. W.; Bormann, K.; Deems, J. S.; Gehrke, F.; Horn, J.; Marks, D. G.; Mattmann, C. A.; McGurk, B. J.; Ramirez, P.; Richardson, M.; Skiles, M.; Winstral, A. H.; Zimdars, P.

    2014-12-01

    The NASA Jet Propulsion Laboratory developed the Airborne Snow Observatory (ASO), an imaging spectrometer and imaging LiDAR system, to quantify snow water equivalent and snow albedo, provide unprecedented knowledge of snow properties, and provide complete, robust inputs to snowmelt runoff models, water management models, and systems of the future. This talk presents results from the second Demonstration Mission that occurred during the intense California drought of spring 2014. With the acquisition of the new cutting edge lidar system, ASO was able to fly higher and as such acquire complete basin coverage for the Tuolumne, Merced, Lakes, and South Fork of Kings River Basins in the California Sierra Nevada. Despite the intensity of the California drought, several snowfalls occurred during the Demonstration Mission and we were able to uniquely map snowfall distribution, providing unprecedented capability to test our understanding of orographics and redistribution of snowfall. A new snow density model and analysis were integrated into the ASO data system. Despite a > 4-fold increase in data volume from the new lidar, the landing-to-data delivery remained at < 24 hrs. ASO SWE and albedo data are assimilated into models of varying complexity and results presented here. We use the ASO data in the Sierra Nevada to evaluate SWE simulations from the NWS SNODAS and SWE reconstruction models. Finally, the ASO data were watched carefully during the drought, suggesting that the Hetch Hetchy reservoir original infrastructure's forecast of falling well short of fill would be biased low and that the reservoir would come close to filling.

  19. Airborne studies of equatorial F layer ionospheric irregularities

    SciTech Connect

    Weber, E.J.; Buchau, J.; Moore, J.G.

    1980-09-01

    Radio wave and optical experiments were conducted onboard a U.S. Air Force research aircraft in March 1977 and March 1978 at low magnetic latitudes to investigate the effects of F region electron density amplitude. Scintillation measurements were used to monitor the development and motion of F region 6300-A O I airglow depletions, spread F, and scintillation producing irregularities that are all associated with low-density bubbles in the postsunset equatorial ionosphere. The 6300-A airglow depletions are the bottomside signature of low plasma density within the bubbles. Examples of multiple airglow depletions and their relation to variations in the F layer virtual height (h'F) and to the occurrence of amplitude scintillations on 250-MHz satellite signals are described. Estimates of the average bottomside electron density, from simultaneous ionosonde measurements and 6300-A airglow intensities, show electron density decreases of approx.66% within the bubbles. These decreases are approximately the same for bubbles observed at the magnetic equator and near Ascension Island (18 /sup 0/S magnetic latitude). The measurements at Ascension Island show that airglow depletions extend away from the magnetic equator into the southern 6300-A intertropical arc. Variations in the maximum poleward extent of airglow depletions and of associated ionospheric irregularities that give rise to amplitude scintillations were observed. These latitudinal variations are interpreted, using field line mapping considerations, as variations in the maximum altitude of plasma bubbles over the magnetic equator. A north-south flight confirms that the overall pattern of airglow depletions and associated ionospheric irregularities extends continuously across the magnetic equator to +-15/sup 0/ magnetic latitude.

  20. An analysis of water in galactic infrared sources using the NASA Lear Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Smith, L. L.; Hilgeman, T.

    1979-01-01

    The Michelson interferometer system on the NASA Lear Jet Airborne Observatory is described as well as the data reduction procedures. The objects observed (standard stars, M stars, a nebula, planets, and the moon) are discussed and the observing parameters are listed for each flight date. The spectra obtained from these data flights are presented, grouped by class of object.

  1. Assimilating Electron Density Profiles Measured by the Real Time Global Ionospheric Radio Observatory - GIRO

    NASA Astrophysics Data System (ADS)

    Reinisch, B. W.; Galkin, I. A.

    2009-04-01

    deduced as 95% uncertainty bounds for a histogram of the distribution of the differences between the ionogram parameters obtained manually and automatically. New ionospheric assimilation models like the Global Assimilation of Ionospheric Measurements (GAIM) differ from prior generation adaptive ionospheric models in that they analyze the uncertainty of the observational inputs before using them as constraints on the physical model drivers. The SAO data exchange format was expanded into the SAO-XML format [Reinisch and Galkin, 2008] to accommodate the expanded data content. In August 2008 during the URSI General Assembly in Chicago, Commission G of URSI accepted SAO-XML as the standard format for ionogram data exchange. All digisonde stations are currently being updated to SAO-XML for ingestion of the scaled data together with the raw ionograms in data centers like the Digital Ionogram Data Base (DIDBase). DIDBase and the digisonde network using SAO-XML truly form a real time Global Ionospheric Radio Observatory (GIRO). Since SAO-XML can easily accommodate data from any digital ionosonde, other ionosonde models can become part of GIRO.

  2. Airborne Astronomy Symposium. A symposium commemorating the tenth anniversary of operations of the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Thronson, H. A., Jr. (Editor); Erickson, E. F. (Editor)

    1984-01-01

    Airborne infrared astronomy is discussed with respect to observations of the solar system, stars, star formation, and the interstellar medium. Far infrared characteristics of the Milky Way, its center, and other galaxies are considered. The instrumentation associated with IR astronomy is addressed.

  3. Progress in the development of airborne remote sensing instrumentation for the National Ecological Observatory Network

    NASA Astrophysics Data System (ADS)

    Kampe, Thomas U.; McCorkel, Joel; Hamlin, Louise; Green, Robert O.; Krause, Keith S.; Johnson, Brian R.

    2011-09-01

    The National Ecological Observatory Network (NEON) is a planned facility of the National Science Foundation with the mission to enable understanding and forecasting of the impacts of climate change, land use change and invasive species on continental-scale ecology. Airborne remote sensing plays a critical role by providing measurements at the scale of individual shrubs and larger plants over hundreds of square kilometers. The NEON Airborne Observation Platform is designed to bridge scales from organism and stand scales, as captured by plot and tower observations, to the scale of satellite based remote sensing. Fused airborne spectroscopy and waveform LiDAR is used to quantify vegetation composition and structure. Panchromatic photography at better than 30 cm resolution will retrieve fine-scale information on land use, roads, impervious surfaces, and built structures. NEON will build three airborne systems to allow for regular coverage of NEON sites and the capacity to respond to investigator requests for specific projects. The system design achieves a balance between performance and development cost and risk, taking full advantage of existing commercial airborne LiDAR and camera components. To reduce risk during NEON construction, an imaging spectrometer design verification unit is being developed at the Jet Propulsion Laboratory to demonstrate that operational and performance requirements can be met. As part of this effort, NEON is also focusing on science algorithm development, computing hardware prototyping and early airborne test flights with similar technologies. This paper presents an overview of the development status of the NEON airborne instrumentation in the context of the NEON mission.

  4. Magnetospheric and ionospheric signals in magnetic observatory monthly means: Electrical conductivity of the deep mantle

    NASA Technical Reports Server (NTRS)

    Mcleod, Malcolm G.

    1994-01-01

    First differences of magnetic observatory monthly means for 1963-1982 were analyzed using techniques of spherical harmonics analysis and power spectral analysis. The external source signal is shown to be primarily zonal in geomagnetic coordinates. Prominent peaks are present in the power spectrum at frequencies of 1.0 cycle/yr and 2.0 cycles/yr. The annual signal is largest on the degree 2 external zonal spherical harmonic, while the semiannual signal is largest on the degree 1 and degree 3 external zonal spherical harmonics. The presence of the semiannual signal on odd-degree spherical harmonics and of the annual signal on even-degree spherical harmonics was predicted from symmetry considerations and the annual cycle of solar inclination. These signals are all modulated by the sunspot frequency and its harmonics. The degree 1 term is believed to be due mainly to magnetopause and ring currents while the degree 2 and degree 3 terms are believed to be due mainly to ionospheric currents. The degree 1 external zonal harmonic has a continuous spectrum in addition to the semiannual spectral peak. A corresponding degree 1 internal term is due to electromagnetic induction. The degree 1 continuous spectrum is useful for study of the electrical conductivity of the deep mantle. A global geomagnetic response function consistent with a mantle conductivity of about 10 S/m at the core-mantle boundary has been derived.

  5. Mid-Infrared Spectroscopy of Mercury from the Kuiper Airborne Observatory

    NASA Astrophysics Data System (ADS)

    Sprague, A. L.; Witteborn, F. C.; Kozlowski, R. W. H.; Wooden, D. H.

    1996-03-01

    We present mid-infrared (5 - 10mic) spectroscopic measurements of the planet Mercury obtained from the Kuiper Airborne Observatory (KAO) using the High Efficiency Infrared Faint Object Grating Spectrograph (HIFOGS). Spectra show features characteristic of plagioclase feldspar that was previously observed near 120 deg mercurian longitude. The spectra also show spectral features that could be interpreted indicative of the presence of pyrrhotite (pyrr). An analysis that fully accounts for the effects of large field of view (FOV), thermal gradients, rough surface and absolute calibration is still underway.

  6. NASA Airborne Snow Observatory: Measuring Spatial Distribution of Snow Water Equivalent and Snow Albedo

    NASA Astrophysics Data System (ADS)

    Joyce, M.; Painter, T. H.; Mattmann, C. A.; Ramirez, P.; Laidlaw, R.; Bormann, K. J.; Skiles, M.; Richardson, M.; Berisford, D. F.

    2015-12-01

    The two most critical properties for understanding snowmelt runoff and timing are the spatial and temporal distributions of snow water equivalent (SWE) and snow albedo. Despite their importance in controlling volume and timing of runoff, snowpack albedo and SWE are still largely unquantified in the US and not at all in most of the globe, leaving runoff models poorly constrained. NASA Jet Propulsion Laboratory, in partnership with the California Department of Water Resources, has developed the Airborne Snow Observatory (ASO), an imaging spectrometer and scanning LiDAR system, to quantify SWE and snow albedo, generate unprecedented knowledge of snow properties for cutting edge cryospheric science, and provide complete, robust inputs to water management models and systems of the future. This poster will describe the NASA Airborne Snow Observatory, its outputs and their uses and applications, along with recent advancements to the system and plans for the project's future. Specifically, we will look at how ASO uses its imaging spectrometer to quantify spectral albedo, broadband albedo, and radiative forcing by dust and black carbon in snow. Additionally, we'll see how the scanning LiDAR is used to determine snow depth against snow-free acquisitions and to quantify snow water equivalent when combined with in-situ constrained modeling of snow density.

  7. NASA Stratospheric Observatory For Infrared Astronomy (SOFIA) Airborne Astronomy Ambassador Program Evaluation Results To Date

    NASA Astrophysics Data System (ADS)

    Harman, Pamela K.; Backman, Dana E.; Clark, Coral

    2015-08-01

    SOFIA is an airborne observatory, capable of making observations that are impossible for even the largest and highest ground-based telescopes, and inspires instrumention development.SOFIA is an 80% - 20% partnership of NASA and the German Aerospace Center (DLR), consisting of a modified Boeing 747SP aircraft carrying a diameter of 2.5 meters (100 inches) reflecting telescope. The SOFIA aircraft is based at NASA Armstrong Flight Research Center, Building 703, in Palmdale, California. The Science Program Office and Outreach Office is located at NASA Ames Research center. SOFIA is one of the programs in NASA's Science Mission Directorate, Astrophysics Division.SOFIA will be used to study many different kinds of astronomical objects and phenomena, including star birth and death, formation of new solar systems, identification of complex molecules in space, planets, comets and asteroids in our solar system, nebulae and dust in galaxies, and ecosystems of galaxies.Airborne Astronomy Ambassador Program:The SOFIA Education and Communications program exploits the unique attributes of airborne astronomy to contribute to national goals for the reform of science, technology, engineering, and math (STEM) education, and to the elevation of public scientific and technical literacy.SOFIA’s Airborne Astronomy Ambassadors (AAA) effort is a professional development program aspiring to improve teaching, inspire students, and inform the community. To date, 55 educators from 21 states; in three cohorts, Cycles 0, 1 and 2; have completed their astronomy professional development and their SOFIA science flight experience. Cycle 3 cohort of 28 educators will be completing their flight experience this fall. Evaluation has confirmed the program’s positive impact on the teacher participants, on their students, and in their communities. Teachers have incorporated content knowledge and specific components of their experience into their curricula, and have given hundreds of presentations and

  8. Determination of the Telluric Water Vapor Absorption Correction for Astronomical Data Obtained from the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Erickson, E. F.; Simpson, J. P.; Kuhn, P. M.; Stearns, L. P.

    1979-01-01

    The amount of telluric water vapor along the line of sight of the Kuiper Airborne Observatory telescope as obtained concommitantly on 23 flights is compared with the NASA-Ames Michelson interferometer and with the NOAA-Boulder radiometer. A strong correlation between the two determinations exists, and a method for computing the atmospheric transmission for a given radiometer reading is established.

  9. Real Time Data/Video/Voice Uplink and Downlink for Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Harper, Doyal A.

    1997-01-01

    LFS was an educational outreach adventure which brought the excitement of astronomical exploration on NASA's Kuiper Airborne Observatory (KAO) to a nationwide audience of children, parents and children through live, interactive television, broadcast from the KAO at an altitude of 41,000 feet during an actual scientific observing mission. The project encompassed three KAO flights during the fall of 1995, including a short practice mission, a daytime observing flight between Moffett Field, California to Houston, Texas, and a nighttime mission from Houston back to Moffett Field. The University of Chicago infrared research team participated in planning the program, developing auxiliary materials including background information and lesson plans, developing software which allowed students on the ground to control the telescope and on-board cameras via the Internet from the Adler Planetarium in Chicago, and acting as on-camera correspondents to explain and answer questions about the scientific research conducted during the flights.

  10. Near real-time ionospheric monitoring over Europe at the Royal Observatory of Belgium using GNSS data

    NASA Astrophysics Data System (ADS)

    Bergeot, Nicolas; Chevalier, Jean-Marie; Bruyninx, Carine; Pottiaux, Eric; Aerts, Wim; Baire, Quentin; Legrand, Juliette; Defraigne, Pascale; Huang, Wei

    2014-10-01

    Various scientific applications and services increasingly demand real-time information on the effects of space weather on Earth's atmosphere. In this frame, the Royal Observatory of Belgium (ROB) takes advantage of the dense EUREF Permanent GNSS Network (EPN) to monitor the ionosphere over Europe from the measured delays in the GNSS signals, and provides publicly several derived products. The main ROB products consist of ionospheric vertical Total Electron Content (TEC) maps over Europe and their variability estimated in near real-time every 15 min on 0.5° × 0.5° grids using GPS observations. The maps are available online with a latency of ~3 min in IONEX format at ftp://gnss.oma.be and as interactive web pages at http://www.gnss.be/Atmospheric_Maps/ionospheric_maps.php. This paper presents the method used in the ROB-IONO software to generate the maps. The ROB-TEC maps show a good agreement with widely used post-processed products such as IGS and ESA with mean differences of 1.3 ± 0.9 and 0.4 ± 1.6 TECu respectively for the period 2012 to mid-2013. In addition, we tested the reliability of the ROB-IONO software to detect abnormal ionospheric activity during the Halloween 2003 ionospheric storm. For this period, the mean differences with IGS and ESA maps are 0.9 ± 2.2 and 0.6 ± 6.8 TECu respectively with maximum differences (>38 TECu) occurring during the major phase of the storm. These differences are due to the lower resolution in time and space of both IGS and ESA maps compared to the ROB-TEC maps. A description of two recent events, one on March 17, 2013 and one on February 27, 2014 also highlights the capability of the method adopted in the ROB-IONO software to detect in near real-time abnormal ionospheric behaviour over Europe. In that frame, ROB maintains a data base publicly available with identified ionospheric events since 2012.

  11. A Compute Perspective: Delivering Decision Support Products in 24 Hours from the Airborne Snow Observatory

    NASA Astrophysics Data System (ADS)

    Ramirez, P.; Mattmann, C. A.; Painter, T. H.; Seidel, F. C.; Trangsrud, A.; Hart, A. F.; Goodale, C. E.; Boardman, J. W.; Heneghan, C.; Verma, R.; Khudikyan, S.; Boustani, M.; Zimdars, P. A.; Horn, J.; Neely, S.

    2013-12-01

    The JPL Airborne Snow Observatory (ASO) must process 100s of GB of raw data to 100s of Terabytes of derived data in 24 hour Near Real Time (NRT) latency in a geographically distributed mobile compute and data-intensive processing setting. ASO provides meaningful information to water resource managers in the Western US letting them know how much water to maintain; or release, and what the prospectus of the current snow season is in the Sierra Nevadas. Providing decision support products processed from airborne data in a 24 hour timeframe is an emergent field and required the team to develop a novel solution as this process is typically done over months. We've constructed a system that combines Apache OODT; with Apache Tika; with the Interactive Data Analysis (IDL)/ENVI programming environment to rapidly and unobtrusively generate, distribute and archive ASO data as soon as the plane lands near Mammoth Lakes, CA. Our system is flexible, underwent several redeployments and reconfigurations, and delivered this critical information to stakeholders during the recent "Snow On" campaign March 2013 - June 2013. This talk will take you through a day in the life of the compute team from data acquisition, delivery, processing, and dissemination. Within this context, we will discuss the architecture of ASO; the open source software we used; the data we stored; and how it was delivered to its users. Moreover we will discuss the logistics, system engineering, and staffing that went into the developing, deployment, and operation of the mobile compute system.

  12. A hardware/software simulation for the video tracking system of the Kuiper Airborne Observatory telescope

    NASA Technical Reports Server (NTRS)

    Boozer, G. A.; Mckibbin, D. D.; Haas, M. R.; Erickson, E. F.

    1984-01-01

    This simulator was created so that C-141 Kuiper Airborne Observatory investigators could test their Airborne Data Acquisition and Management System software on a system which is generally more accessible than the ADAMS on the plane. An investigator can currently test most of his data acquisition program using the data computer simulator in the Cave. (The Cave refers to the ground-based computer facilities for the KAO and the associated support personnel.) The main Cave computer is interfaced to the data computer simulator in order to simulate the data-Exec computer communications. However until now, there has been no way to test the data computer interface to the tracker. The simulator described here simulates both the KAO Exec and tracker computers with software which runs on the same Hewlett-Packard (HP) computer as the investigator's data acquisition program. A simulator control box is hardwired to the computer to provide monitoring of tracker functions, to provide an operator panel similar to the real tracker, and to simulate the 180 deg phase shifting of the chopper squre-wave reference with beam switching. If run in the Cave, one can use their Exec simulator and this tracker simulator.

  13. Fiber-coupled high resolution infrared array spectrometer for the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Glenar, D. A.; Reuter, D.; Mumma, M. J.; Chin, G.; Wiedemann, G.; Jennings, D.

    1990-01-01

    A novel cryogenic grating spectrometer (FCAS) is being designed for observations of volatiles in cometary and planetary atmospheres, and in newly forming planetary systems. The instrument features two-dimensional detector arrays coupled to a high-dispersion echelle by infrared fibers, and will achieve a spectral resolving power of about 40,000. The primary observational platform for this instrument will be the Kuiper Airborne Observatory, but it will also be configured for use at ground-based observatories. Initially, the spectrometer will use a 58 x 62, 1- to 5-micron InSb array. Larger-format IR arrays and arrays of different composition, will later be incorporated as they become available. The instrument will be used in two modes. The first uses a large format IR array in the spectral image plane for the customary one-dimensional spectral-one-dimensional spatial coverage. In the second mode, a massive, coherent bundle of infrared transmitting ZrF4 fibers will be installed after the dispersive element, to reformat the two-dimensional array into an elongated one-dimensional array for wide spectral coverage, allowing multiple lines to be measured in a single integration with high sensitivity. The overall instrument design is discussed, and the system sensitivity is estimated.

  14. Remote sensing of the Ionosphere over the Murchison Radio Observatory, Western Australia, Leading to an Understanding of Fine Scale Behaviour

    NASA Astrophysics Data System (ADS)

    Herne, D. E.; Lynch, M. J.; Coster, A. J.; Oberoi, D.; Carrano, C. S.; Williams, J.; Kennewell, J.; Groves, K. M.

    2010-12-01

    The Murchison Radio Observatory (MRO) is the home of radio astronomy in Australia. Projects currently under development at the MRO include a low-frequency instrument, the Murchison Widefield Array (MWA). The MWA is an aperture synthesis, imaging array that when complete will comprise approximately 8,000 dipole antennas operating in the frequency range, 80 to 300 MHz. Signals in this frequency range are subject to distortions caused by the ionosphere. The effects of scintillation and faraday rotation degrade image quality. In order to ‘unwind’ faraday rotation, the distribution of the electron content in the ionosphere must be determined. Knowledge of the absolute total electron content (TEC) provides information about this distribution. This step is necessary in order to study processes in space involving magnetism. Over a period of two years, TEC measurements have been made over the MRO using high-precision, dual-frequency, GPS systems. Continuous measurements were performed for 12 months and campaign-based measurements at other times, due to the remote location of the MRO. The determination of the GPS receiver biases used to calculate TEC were studied with respect to changing temperatures. TEC measurements are compared to the results of modelling conducted previously (Kennewell et. al. 2005) as part of Australia’s bid to host the Square Kilometre Array radio telescope (SKA). Further, due to the fine grained nature of measurements (on the order of 0.01-0.03 TEC units), fine-scale structure can be resolved in the behaviour of the ionosphere in both temporal and spatial domains and is discussed. This work too, is laying a foundation for the accurate characterisation of the ionosphere over the MRO which is also the possible future site of the SKA. Plans to extend this work and the implementation of useful new measurement regimes are discussed, enabled by facilities currently being established as part of Australia’s ongoing commitment to radio astronomy on the

  15. Calibration and Validation of the National Ecological Observatory Network's Airborne Imaging Spectrometers

    NASA Astrophysics Data System (ADS)

    Leisso, N.

    2015-12-01

    The National Ecological Observatory Network (NEON) is being constructed by the National Science Foundation and is slated for completion in 2017. NEON is designed to collect data to improve the understanding of changes in observed ecosystems. The observatory will produce data products on a variety of spatial and temporal scales collected from individual sites strategically located across the U.S. including Alaska, Hawaii, and Puerto Rico. Data sources include standardized terrestrial, instrumental, and aquatic observation systems in addition to three airborne remote sensing observation systems installed into leased Twin Otter aircraft. The Airborne Observation Platforms (AOP) are designed to collect 3-band aerial imagery, waveform and discrete LiDAR, and high-fidelity imaging spectroscopy data over the NEON sites annually at or near peak-greenness. The NEON Imaging Spectrometer (NIS) is a Visible and Shortwave Infrared (VSWIR) sensor designed by NASA JPL for ecological applications. Spectroscopic data is collected at 5-nm intervals across the solar-reflective spectral region (380-nm to 2500-nm) in a 34-degree FOV swath. A key uncertainty driver to the derived remote sensing NEON data products is the calibration of the imaging spectrometers. In addition, the calibration and accuracy of the higher-level data product algorithms is essential to the overall NEON mission to detect changes in the collected ecosystems over the 30-year expected lifetime. The typical calibration workflow of the NIS consists of the characterizing the focal plane, spectral calibration, and radiometric calibration. Laboratory spectral calibration is based on well-defined emission lines in conjunction with a scanning monochromator to define the individual spectral response functions. The radiometric calibration is NIST traceable and transferred to the NIS with an integrating sphere calibrated through the use of transfer radiometers. The laboratory calibration is monitored and maintained through

  16. Kuiper Airborne Observatory's Telescope Stabilization System: Disturbance Sensitivity Reduction Via Velocity Loop Feedback

    NASA Technical Reports Server (NTRS)

    Lawrence, David P.; Tsui, K. C.; Tucker, John; Mancini, Ronald E. (Technical Monitor)

    1995-01-01

    In July of 1994 the Kuiper Airborne Observatory's (KAO) Telescope Stabilization System (TSS) was upgraded to meet performance goals necessary to view the Shoemaker-Levy 9 comet collision with Jupiter. The KAO is a modified C-141 Aircraft supporting a 36 inch Infrared telescope used to gather and analyze astronomical data. Before the upgrade, the TSS exhibited approximately a 10 arc-second resolution pointing accuracy. The majority of the inaccuracy was attributable to aircraft vibration and wind buffeting entering through the aircraft's telescope door opening; in other words, the TSS was overly sensitive to external disturbances. Because of power limitations and noise requirements, improving the pointing accuracy of the telescope required more sophistication than simply raising the bandwidth as some classical control strategies might suggest. Instead, relationships were developed between the disturbance sensitivity and closed loop transfer functions. These relationships suggested that employing velocity feedback along with an increase in current loop gain would dramatically improve the pointing resolution of the TSS by decreasing the control system's sensitivity to external disturbances. With the implementation of some classical control techniques and the above philosophy, the KAO's TSS's resolution was improved to approximately 2-3 arc-seconds.

  17. Validating SWE reconstruction using Airborne Snow Observatory measurements in the Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Bair, N.; Rittger, K.; Davis, R. E.; Dozier, J.

    2015-12-01

    The Airborne Snow Observatory (ASO) program offers high resolution estimates of snow water equivalent (SWE) in several small basins across California during the melt season. Primarily, water managers use this information to model snowmelt runoff into reservoirs. Another, and potentially more impactful, use of ASO SWE measurements is in validating and improving satellite-based SWE estimates which can be used in austere regions with no ground-based snow or water measurements, such as Afghanistan's Hindu Kush. Using the entire ASO dataset to date (2013-2015) which is mostly from the Upper Tuolumne basin, but also includes measurements from 2015 in the Kings, Rush Creek, Merced, and Mammoth Lakes basins, we compare ASO measurements to those from a SWE reconstruction method. Briefly, SWE reconstruction involves downscaling energy balance forcings to compute potential melt energy, then using satellite-derived estimates of fractional snow covered area (fSCA) to estimate snow melt from potential melt. The snowpack can then be built in reverse, given a remotely-sensed date of snow disappearance (fSCA=0). Our model has improvements over previous iterations in that it: uses the full energy balance (compared to a modified degree-day) approach, models bulk and surface snow temperatures, accounts for ephemeral snow, and uses a remotely-sensed snow albedo adjusted for impurities. To check that ASO provides accurate snow measurements, we compare fSCA derived from ASO snow depth at 3 m resolution with fSCA from a spectral unmixing algorithm for LandSAT at 30 m, and from binary SCA estimates from Geoeye at 0.5 m from supervised classification. To conclude, we document how our reconstruction model has evolved over the years and provide specific examples where improvements have been made using ASO and other verification sources.

  18. Revisiting Runoff Model Calibration: Airborne Snow Observatory Results Allow Improved Modeling Results

    NASA Astrophysics Data System (ADS)

    McGurk, B. J.; Painter, T. H.

    2014-12-01

    Deterministic snow accumulation and ablation simulation models are widely used by runoff managers throughout the world to predict runoff quantities and timing. Model fitting is typically based on matching modeled runoff volumes and timing with observed flow time series at a few points in the basin. In recent decades, sparse networks of point measurements of the mountain snowpacks have been available to compare with modeled snowpack, but the comparability of results from a snow sensor or course to model polygons of 5 to 50 sq. km is suspect. However, snowpack extent, depth, and derived snow water equivalent have been produced by the NASA/JPL Airborne Snow Observatory (ASO) mission for spring of 20013 and 2014 in the Tuolumne River basin above Hetch Hetchy Reservoir. These high-resolution snowpack data have exposed the weakness in a model calibration based on runoff alone. The U.S. Geological Survey's Precipitation Runoff Modeling System (PRMS) calibration that was based on 30-years of inflow to Hetch Hetchy produces reasonable inflow results, but modeled spatial snowpack location and water quantity diverged significantly from the weekly measurements made by ASO during the two ablation seasons. The reason is that the PRMS model has many flow paths, storages, and water transfer equations, and a calibrated outflow time series can be right for many wrong reasons. The addition of a detailed knowledge of snow extent and water content constrains the model so that it is a better representation of the actual watershed hydrology. The mechanics of recalibrating PRMS to the ASO measurements will be described, and comparisons in observed versus modeled flow for both a small subbasin and the entire Hetch Hetchy basin will be shown. The recalibrated model provided a bitter fit to the snowmelt recession, a key factor for water managers as they balance declining inflows with demand for power generation and ecosystem releases during the final months of snow melt runoff.

  19. Photometer dewar system for NASA C141 airborne telescope (Kuiper Flying Observatory). [design analysis/performance tests

    NASA Technical Reports Server (NTRS)

    Ney, E. P.

    1974-01-01

    The design, calibration, and testing of a photometer to be used in an airborne telescope is described. A description of the cryogenics of the photometer is given, and photographs and blueprints of the photometer are included. The photometer is designed with a focal plane beam switching system so that the airplane telescope can be used in a normal optical mode at the bent Cassegrain focus and with the photometer operating in the pressurized cabin of the airplane. The concept was to produce a system which could be used in almost the same manner as ground based infrared photometers and dewars of the O'Brien Observatory at the University of Minnesota.

  20. Airborne LiDAR and hyperspectral mapping of snow depth and albedo in the Upper Colorado River Basin, Colorado, USA by the NASA JPL Airborne Snow Observatory

    NASA Astrophysics Data System (ADS)

    Deems, J. S.; Painter, T. H.

    2014-12-01

    Operational hydrologic simulation and forecasting in snowmelt-dominated watersheds currently relies on indices of snow accumulation and melt from measurements at a small number of point locations or geographically-limited manual surveys. These data sources cannot adequately characterize the spatial distribution of snow depth/water equivalent, which is the primary determinant of snowpack volume and runoff rates. The NASA JPL Airborne Snow Observatory's airborne laser scanning system maps snow depth at high spatial and temporal resolutions, and is paired with a hyperspectral imager to provide an unprecedented snowpack monitoring capability and enabling a new operational paradigm. We present the initial results from this new application of multi-temporal LiDAR and hyperspectral mapping. During the snowmelt seasons of 2013 and 2014, the ASO mapped snow depth and albedo in the Uncompahgre River Basin in Colorado's Upper Colorado River Basin on a nominally monthly basis. These products enable an assessment and comparison of spatial snow accumulation and melt processes in two years with very different snowmelt hydrographs.

  1. Calibration and Data Efforts of the National Ecological Observatory Network (NEON) Airborne Observation Platform during its Engineering Development Phase

    NASA Astrophysics Data System (ADS)

    Adler, J.; Goulden, T.; Kampe, T. U.; Leisso, N.; Musinsky, J.

    2014-12-01

    The National Ecological Observatory Network (NEON) has collected airborne photographic, lidar, and imaging spectrometer data in 5 of 20 unique ecological climate regions (domains) within the United States. As part of its mission to detect and forecast ecological change at continental scales over multiple decades, NEON Airborne Observation Platform (AOP) will aerially survey the entire network of 60 core and re-locatable terrestrial sites annually, each of which are a minimum of 10km-by-10km in extent. The current effort encompasses three years of AOP engineering test flights; in 2017 NEON will transition to full operational status in all 20 domains. To date the total airborne data collected spans 34 Terabytes, and three of the five sampled domain's L1 data are publically available upon request. The large volume of current data, and the expected data collection over the remaining 15 domains, is challenging NEON's data distribution plans, backup capability, and data discovery processes. To provide the public with the highest quality data, calibration and validation efforts of the camera, lidar, and spectrometer L0 data are implemented to produce L1 datasets. Where available, the collected airborne measurements are validated against ground reference points and surfaces and adjusted for instrumentation and atmospheric effects. The imaging spectrometer data is spectrally and radiometrically corrected using NIST-traceable procedures. This presentation highlights three years of flight operation experiences including:1) Lessons learned on payload re-configuration, data extraction, data distribution, permitting requirements, flight planning, and operational procedures2) Lidar validation through control data comparisons collected at the Boulder Municipal Airport (KBDU), the site of NEON's new hangar facility3) Spectrometer calibration efforts, to include both the laboratory and ground observations

  2. Analysis of Snow Albedo, Grain Size and Radiative Forcing based on the Airborne Snow Observatory (ASO) Imaging Spectroscopy Data

    NASA Astrophysics Data System (ADS)

    Seidel, F. C.; Painter, T. H.

    2013-12-01

    Climate is expected to be most vulnerable in mountainous and arctic regions where the atmosphere and the hydrosphere are directly linked to the cryosphere. A combination of modeling and large-scale observational efforts is required to investigate related scientific questions. NASA's Airborne Snow Observatory (ASO) at the Jet Propulsion Laboratory addresses some of these needs by establishing new quantitative observational capabilities in regional mapping of mountain snow properties. In addition, ASO's key products showed that we are able to achieve societal benefits by improving water resources management. We will show the first analysis of snow optical products (albedo, grain size, and radiative forcing) from the spring 2013 ASO campaign in the Sierra Nevada, CA, USA. In addition, we will present the retrieval methods used to derive these products based on airborne imaging spectroscopy, LiDAR, as well as radiative transfer models. The preliminary findings provide new important insights into the temporal and spatial aspects of Western US mountain snow and its melt.

  3. Ionization and emission processes in the auroral and equatorial ionosphere. Final report, 12 April 1977-30 September 1980

    SciTech Connect

    Eather, R.H.

    1980-10-15

    This report describes the support service supplied by KEO Consultant to the operation, and improvement of the all-Sky-Imaging-Photometer on the NKC-135 Airborne Ionospheric Observatory. Data analysis and results are also described. A new digitizing system constructed to facilitate analysis of video images is described, together with the associated computer software.

  4. A Rapid Turn-around, Scalable Big Data Processing Capability for the JPL Airborne Snow Observatory (ASO) Mission

    NASA Astrophysics Data System (ADS)

    Mattmann, C. A.

    2014-12-01

    The JPL Airborne Snow Observatory (ASO) is an integrated LIDAR and Spectrometer measuring snow depth and rate of snow melt in the Sierra Nevadas, specifically, the Tuolumne River Basin, Sierra Nevada, California above the O'Shaughnessy Dam of the Hetch Hetchy reservoir, and the Uncompahgre Basin, Colorado, amongst other sites. The ASO data was delivered to water resource managers from the California Department of Water Resources in under 24 hours from the time that the Twin Otter aircraft landed in Mammoth Lakes, CA to the time disks were plugged in to the ASO Mobile Compute System (MCS) deployed at the Sierra Nevada Aquatic Research Laboratory (SNARL) near the airport. ASO performed weekly flights and each flight took between 500GB to 1 Terabyte of raw data, which was then processed from level 0 data products all the way to full level 4 maps of Snow Water Equivalent, albedo mosaics, and snow depth from LIDAR. These data were produced by Interactive Data analysis Language (IDL) algorithms which were then unobtrusively and automatically integrated into an Apache OODT and Apache Tika based Big Data processing system. Data movement was both electronic and physical including novel uses of LaCie 1 and 2 TeraByte (TB) data bricks and deployment in rugged terrain. The MCS was controlled remotely from the Jet Propulsion Laboratory, California Institute of Technology (JPL) in Pasadena, California on behalf of the National Aeronautics and Space Administration (NASA). Communication was aided through the use of novel Internet Relay Chat (IRC) command and control mechanisms and through the use of the Notifico open source communication tools. This talk will describe the high powered, and light-weight Big Data processing system that we developed for ASO and its implications more broadly for airborne missions at NASA and throughout the government. The lessons learned from ASO show the potential to have a large impact in the development of Big Data processing systems in the years

  5. Constraining Annual Water Balance Estimates with Basin-Scale Observations from the Airborne Snow Observatory during the Current Californian Drought

    NASA Astrophysics Data System (ADS)

    Bormann, K.; Painter, T. H.; Marks, D. G.; Hedrick, A. R.; Deems, J. S.; Patterson, V.; McGurk, B. J.

    2015-12-01

    One of the great unknowns in mountain hydrology is how much water is stored within a seasonal snowpack at the basin scale. Quantifying mountain water resources is critical for assisting with water resource management, but has proven elusive due to high spatial and temporal variability of mountain snow cover, complex terrain, accessibility constraints and limited in-situ networks. The Airborne Snow Observatory (ASO, aso.jpl.nasa.gov) uses coupled airborne LiDAR and spectrometer instruments for high resolution snow depth retrievals which are used to derive unprecedented basin-wide estimates of snow water mass (snow water equivalent, SWE). ASO has been operational over key basins in the Sierra Nevada Mountains in California since 2013. Each operational year has been very dry, with precipitation in 2013 at 75% of average, 2014 at 50% of average and 2015 - the lowest snow year on record for the region. With vastly improved estimates of the snowpack water content from ASO, we can now for the first time conduct observation-based mass balance accounting of surface water in snow-dominated basins, and reconcile these estimates with observed reservoir inflows. In this study we use ASO SWE data to constrain mass balance accounting of basin annual water storages to quantify the water contained within the snowpack above the Hetch Hetchy water supply reservoir (Tuolumne River basin, California). The analysis compares and contrasts annual snow water volumes from observed reservoir inflows, snow water volume estimates from ASO, a physically based model that simulates the snowpack from meteorological inputs and a semi-distributed hydrological model. The study provides invaluable insight to the overall volume of water contained within a seasonal snowpack during a severe drought and how these quantities are simulated in our modelling systems. We envisage that this research will be of great interest to snowpack modellers, hydrologists, dam operators and water managers worldwide.

  6. Integrating snow albedo from the Airborne Snow Observatory into the distributed energy balance snowmelt model iSnobal

    NASA Astrophysics Data System (ADS)

    Skiles, M.; Painter, T. H.; Marks, D. G.; Hedrick, A. R.

    2015-12-01

    Since 2013 the Airborne Snow Observatory (ASO) has been measuring spatial and temporal distribution of both snow water equivalent and snow albedo, the two most critical properties for understanding snowmelt runoff and timing, across key basins in the Western US. It is generally understood that net solar radiation (as controlled by variations in snow albedo and irradiance) provides the energy available for melt in almost all snow-covered environments. Until now, sparse measurements have restricted the ability to utilize measured net solar radiation in energy balance models, and current process simulations and model prediction of albedo evolution rely on oversimplifications of the processes. Data from ASO offers the unprecedented opportunity to utilize weekly measurements of spatially extensive spectral snow albedo to constrain and update snow albedo in a distributed snowmelt model for the first time. Here, we first investigate the sensitivity of the snow energy balance model SNOBAL to prescribed changes in snow albedo at two instrumented alpine catchments: at the point scale across 10 years at Senator Beck Basin Study Area in the San Juan Mountains, southwestern Colorado, and at the distributed scale across 25 years at Reynolds Creek Experimental Watershed, Idaho. We then compare distributed energy balance and snowmelt results across the ASO measurement record in the Tuolumne Basin in the Sierra Nevada Mountains, California, for model runs with and without integrated snow albedo from ASO.

  7. The Planet Mercury Surface Spectroscopy and Analysis from the Kuiper Airborne Observatory and Analysis and Modeling to Determine Surface Composition

    NASA Technical Reports Server (NTRS)

    Sprague, Ann

    1997-01-01

    We had two successful flights to observe Mercury from the Kuiper Airborne Observatory (KAO) using High-efficiency Infrared Faint-Object Grating Spectrograph (HIFOGS). Flights were May 8, 1995 (eastern elongation) and July 6, 1995 (western elongation) For the observations one half of the primary mirror was covered to prevent sunlight from entering the telescope. All equipment and the airplane and its crew performed well. These flights were historical firsts for the KAO and for spectroscopy of Mercury in that it was the first time any spectroscopic observations of Mercury from above the Earth's atmosphere had been made. It was the first time the KAO had been used to @bserve an object less than 30 degrees from the Sun. Upon completion of the basic data reduction it became obvious that extensive modeling and analysis would be required to understand the data. It took three years of a graduate student's time and part time the PI to do the thermal modeling and the spectroscopic analysis. This resulted in a lengthy publication. A copy of this publication is attached and has all the data obtained in both KAO flights and the results clearly presented. Notable results are: (1) The observations found an as yet unexplained 5 micron emission enhancement that we think may be a real characteristic of Mercury's surface but could have an instrumental cause; (2) Ground-based measurements or an emission maximum at 7.7 microns were corroborated. The chemical composition of Mercury's surface must be feldspathic in order to explain spectra features found in the data obtained during the KAO flights.

  8. The Airborne Snow Observatory: fusion of imaging spectrometer and scanning lidar for studies of mountain snow cover (Invited)

    NASA Astrophysics Data System (ADS)

    Painter, T. H.; Andreadis, K.; Berisford, D. F.; Goodale, C. E.; Hart, A. F.; Heneghan, C.; Deems, J. S.; Gehrke, F.; Marks, D. G.; Mattmann, C. A.; McGurk, B. J.; Ramirez, P.; Seidel, F. C.; Skiles, M.; Trangsrud, A.; Winstral, A. H.; Kirchner, P.; Zimdars, P. A.; Yaghoobi, R.; Boustani, M.; Khudikyan, S.; Richardson, M.; Atwater, R.; Horn, J.; Goods, D.; Verma, R.; Boardman, J. W.

    2013-12-01

    Snow cover and its melt dominate regional climate and water resources in many of the world's mountainous regions. However, we face significant water resource challenges due to the intersection of increasing demand from population growth and changes in runoff total and timing due to climate change. Moreover, increasing temperatures in desert systems will increase dust loading to mountain snow cover, thus reducing the snow cover albedo and accelerating snowmelt runoff. The two most critical properties for understanding snowmelt runoff and timing are the spatial and temporal distributions of snow water equivalent (SWE) and snow albedo. Despite their importance in controlling volume and timing of runoff, snowpack albedo and SWE are still poorly quantified in the US and not at all in most of the globe, leaving runoff models poorly constrained. Recognizing this need, JPL developed the Airborne Snow Observatory (ASO), an imaging spectrometer and imaging LiDAR system, to quantify snow water equivalent and snow albedo, provide unprecedented knowledge of snow properties, and provide complete, robust inputs to snowmelt runoff models, water management models, and systems of the future. Critical in the design of the ASO system is the availability of snow water equivalent and albedo products within 24 hours of acquisition for timely constraint of snowmelt runoff forecast models. In spring 2013, ASO was deployed for its first year of a multi-year Demonstration Mission of weekly acquisitions in the Tuolumne River Basin (Sierra Nevada) and monthly acquisitions in the Uncompahgre River Basin (Colorado). The ASO data were used to constrain spatially distributed models of varying complexities and integrated into the operations of the O'Shaughnessy Dam on the Hetch Hetchy reservoir on the Tuolumne River. Here we present the first results from the ASO Demonstration Mission 1 along with modeling results with and without the constraint by the ASO's high spatial resolution and spatially

  9. Converting Snow Depth to SWE: The Fusion of Simulated Data with Remote Sensing Retrievals and the Airborne Snow Observatory

    NASA Astrophysics Data System (ADS)

    Bormann, K.; Marks, D. G.; Painter, T. H.; Hedrick, A. R.; Deems, J. S.

    2015-12-01

    Snow cover monitoring has greatly benefited from remote sensing technology but, despite their critical importance, spatially distributed measurements of snow water equivalent (SWE) in mountain terrain remain elusive. Current methods of monitoring SWE rely on point measurements and are insufficient for distributed snow science and effective management of water resources. Many studies have shown that the spatial variability in SWE is largely controlled by the spatial variability in snow depth. JPL's Airborne Snow Observatory mission (ASO) combines LiDAR and spectrometer instruments to retrieve accurate and very high-resolution snow depth measurements at the watershed scale, along with other products such as snow albedo. To make best use of these high-resolution snow depths, spatially distributed snow density data are required to leverage SWE from the measured snow depths. Snow density is a spatially and temporally variable property that cannot yet be reliably extracted from remote sensing techniques, and is difficult to extrapolate to basin scales. However, some physically based snow models have shown skill in simulating bulk snow densities and therefore provide a pathway for snow depth to SWE conversion. Leveraging model ability where remote sensing options are non-existent, ASO employs a physically based snow model (iSnobal) to resolve distributed snow density dynamics across the basin. After an adjustment scheme guided by in-situ data, these density estimates are used to derive the elusive spatial distribution of SWE from the observed snow depth distributions from ASO. In this study, we describe how the process of fusing model data with remote sensing retrievals is undertaken in the context of ASO along with estimates of uncertainty in the final SWE volume products. This work will likely be of interest to those working in snow hydrology, water resource management and the broader remote sensing community.

  10. The NASA Airborne Snow Observatory: Demonstration Mission-3 and the Path Forward to a Broader ASO Program

    NASA Astrophysics Data System (ADS)

    Painter, T. H.

    2015-12-01

    The NASA Airborne Snow Observatory (ASO), an imaging spectrometer and imaging LiDAR system, to quantify snow water equivalent and snow albedo, provide unprecedented knowledge of snow properties, and provide complete, robust inputs to snowmelt runoff models, water management models, and systems of the future. This talk presents results from the third Demonstration Mission that occurred during the intense California drought of spring 2015, a snow year far worse than the previously worst snow year on record of 2014, and an overview of the various analyses that are finally available due to the uniqueness of the ASO data. In 2015, ASO provided complete basin coverage for the Tuolumne, Merced, Lakes, Rush Creek, and Middle+South Forks of Kings River Basins in the California Sierra Nevada and the Upper Rio Grande, Conejos, and Uncompahgre Basins in the Colorado Rocky Mountains. ASO performed its first wintertime acquisitions in the Tuolumne Basin in response to water managers' needs to quantify SWE volume in what was already realized as dire conditions. Analyses show that with ASO data, river flows and reservoir inflows from the ASO acquisition date to 1 July can be estimated with uncertainties of less than 2%. These results provide enormous value in management operational flexibility for the diversity of needs, and provide strong scientific constraints on the physical processes controlling snowmelt runoff. Snowmelt runoff models are markedly better constrained due to the now accurate knowledge of the distribution of snow water equivalent. With the ASO high-resolution spectrometer and lidar data for a snow-free acquisition, we can determine surface classifications, vegetation heights, and river networks. These data allow runoff models to be accurately and rapidly developed with unprecedented accuracy. These data are now being used to constrain models of varying complexity. Finally, we discuss the path forward on expanding ASO to cover the entire Sierra Nevada and the

  11. Ionospheric physics

    SciTech Connect

    Sojka, J.J. )

    1991-01-01

    Advances in all areas of ionospheric research are reviewed for the 1987-1990 time period. Consideration is given to the equatorial ionosphere, the midlatitude ionosphere and plasmasphere, the auroral ionosphere, the polar ionosphere and polar wind, ionospheric electrodynamic inputs, plasma waves and irregularities, active experiments, ionospheric forecasting, and coupling the ionosphere with other regions.

  12. High fidelity remote sensing of snow properties from MODIS and the Airborne Snow Observatory: Snowflakes to Terabytes

    NASA Astrophysics Data System (ADS)

    Painter, T.; Mattmann, C. A.; Brodzik, M.; Bryant, A. C.; Goodale, C. E.; Hart, A. F.; Ramirez, P.; Rittger, K. E.; Seidel, F. C.; Zimdars, P. A.

    2012-12-01

    The response of the cryosphere to climate forcings largely determines Earth's climate sensitivity. However, our understanding of the strength of the simulated snow albedo feedback varies by a factor of three in the GCMs used in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, mainly caused by uncertainties in snow extent and the albedo of snow-covered areas from imprecise remote sensing retrievals. Additionally, the Western US and other regions of the globe depend predominantly on snowmelt for their water supply to agriculture, industry and cities, hydroelectric power, and recreation, against rising demand from increasing population. In the mountains of the Upper Colorado River Basin, dust radiative forcing in snow shortens snow cover duration by 3-7 weeks. Extended to the entire upper basin, the 5-fold increase in dust load since the late-1800s results in a 3-week earlier peak runoff and a 5% annual loss of total runoff. The remotely sensed dynamics of snow cover duration and melt however have not been factored into hydrological modeling, operational forecasting, and policymaking. To address these deficiencies in our understanding of snow properties, we have developed and validated a suite of MODIS snow products that provide accurate fractional snow covered area and radiative forcing of dust and carbonaceous aerosols in snow. The MODIS Snow Covered Area and Grain size (MODSCAG) and MODIS Dust Radiative Forcing in Snow (MODDRFS) algorithms, developed and transferred from imaging spectroscopy techniques, leverage the complete MODIS surface reflectance spectrum. The two most critical properties for understanding snowmelt runoff and timing are the spatial and temporal distributions of snow water equivalent (SWE) and snow albedo. We have created the Airborne Snow Observatory (ASO), an imaging spectrometer and scanning LiDAR system, to quantify SWE and snow albedo, generate unprecedented knowledge of snow properties, and provide complete

  13. INTERMAGNET and magnetic observatories

    USGS Publications Warehouse

    Love, Jeffrey J.; Chulliat, Arnaud

    2012-01-01

    A magnetic observatory is a specially designed ground-based facility that supports time-series measurement of the Earth’s magnetic field. Observatory data record a superposition of time-dependent signals related to a fantastic diversity of physical processes in the Earth’s core, mantle, lithosphere, ocean, ionosphere, magnetosphere, and, even, the Sun and solar wind.

  14. Tree species identification in an African Savanna with airborne imaging spectroscopy and LiDAR from the Carnegie Airborne Observatory (CAO) using stacked support vector machines

    NASA Astrophysics Data System (ADS)

    Baldeck, C. A.; Colgan, M.; Féret, J.; Asner, G. P.

    2012-12-01

    Airborne remote sensing data provide promising opportunities for species identification of individual tree and shrub crowns across large areas which cannot be mapped from the ground. Previous investigations of the potential for species identification of crowns from airborne data have focused on pixel-level information (0.5-1m2), and thus have been unable to take advantage of the structural information that exist at the crown level. Hyperspectral data consisting of 58 bands from 517 to 1054nm and LiDAR (light detection and ranging) data providing vegetation height information were acquired over several landscapes within Kruger National Park, South Africa, by the CAO in 2008 at 1.1m spatial resolution. Over 1,000 individual trees and shrubs were mapped and identified in the field to construct species spectral and structural libraries. We used stacked support vector machines (SVM) that incorporate pixel-level spectral information and crown-level structural information to predict species identity for individual tree crowns. The addition of a crown-level classification step that incorporates crown structural information significantly improved model accuracy by ~6% and our prediction accuracy of the final model was ~75% for 16 species classes. This model was then used to predict the species identity of individual crowns across multiple airborne-mapped landscapes, made possible by an automated crown segmentation algorithm. The resultant species maps will make it possible to examine the environmental controls over individual species distributions and tree community composition, and provide important landscape-scale species distribution information relevant to park management and conservation.

  15. Molecular Shocks Associated with Massive Young Stars: CO Line Images with a New Far-Infrared Spectroscopic Camera on the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Watson, Dan M.

    1997-01-01

    Under the terms of our contract with NASA Ames Research Center, the University of Rochester (UR) offers the following final technical report on grant NAG 2-958, Molecular shocks associated with massive young stars: CO line images with a new far-infrared spectroscopic camera, given for implementation of the UR Far-Infrared Spectroscopic Camera (FISC) on the Kuiper Airborne Observatory (KAO), and use of this camera for observations of star-formation regions 1. Two KAO flights in FY 1995, the final year of KAO operations, were awarded to this program, conditional upon a technical readiness confirmation which was given in January 1995. The funding period covered in this report is 1 October 1994 - 30 September 1996. The project was supported with $30,000, and no funds remained at the conclusion of the project.

  16. SOFIA (Stratospheric Observatory For Infrared Astronomy) with Telescope Configuration Changes

    NASA Technical Reports Server (NTRS)

    2001-01-01

    SOFIA (Stratospheric Observatory For Infrared Astronomy) with Telescope Configuration Changes Artwork. Concepts: Based on 18 Years of Experience of Kuiper Airborne Observatory (KAO) Operation, Characteristics, Operations and Science

  17. Automatic ionospheric layers detection: Algorithms analysis

    NASA Astrophysics Data System (ADS)

    Molina, María G.; Zuccheretti, Enrico; Cabrera, Miguel A.; Bianchi, Cesidio; Sciacca, Umberto; Baskaradas, James

    2016-03-01

    Vertical sounding is a widely used technique to obtain ionosphere measurements, such as an estimation of virtual height versus frequency scanning. It is performed by high frequency radar for geophysical applications called "ionospheric sounder" (or "ionosonde"). Radar detection depends mainly on targets characteristics. While several targets behavior and correspondent echo detection algorithms have been studied, a survey to address a suitable algorithm for ionospheric sounder has to be carried out. This paper is focused on automatic echo detection algorithms implemented in particular for an ionospheric sounder, target specific characteristics were studied as well. Adaptive threshold detection algorithms are proposed, compared to the current implemented algorithm, and tested using actual data obtained from the Advanced Ionospheric Sounder (AIS-INGV) at Rome Ionospheric Observatory. Different cases of study have been selected according typical ionospheric and detection conditions.

  18. Comparison of airborne CO/sub 2/ flask samples and measurements from the Mauna Loa Observatory during the HAMEC project (June 1980)

    SciTech Connect

    Herbert, G.A.; Harris, T.B.; Chin, J.F.S.

    1983-08-20

    During June 1980, the Hawaii Mesoscale Energy and Climate Project (HAMEC) field program was conducted in the vicinity of the island of Hawaii. The objective of the program was to use the NOAA P3 aircraft to measure meteorological variables upwind and downwind of the island to provide data to evaluate mesoscale models of airflow and cloud physics. One specific objective was to obtain flask samples upwind of the island to confirm that the CO/sub 2/ values observed at the Mauna Loa Observatory (MLO) are representative of the free air at comparable altitudes. On 2 days, carbon dioxide flask samples were exposed aboard the aircraft at the altitude of the observatory and immediately above the trade inversion. Flask pairs in reasonable agreement were obtained on both occasions. During the same period the sampling conditions at MLO were free of obvious local contamination. The average difference between the aircraft measurements at the altitude of the observatory and the continuous CO/sub 2/ record from the observatory over the same period of time was 0.8 mole fraction in ppM. Differences in the individual measurements are discussed with respect to prevailing meteorological conditions. 11 references, 2 figures, 2 tables.

  19. SOFIA's Airborne Astronomy Ambassadors: An External Evaluation of Cycle 1

    ERIC Educational Resources Information Center

    Phillips, Michelle

    2015-01-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) represents a partnership between NASA and the German Aerospace Center (DLR). The observatory itself is a Boeing 747 SP that has been modified to serve as the world's largest airborne research observatory. The SOFIA Airborne Astronomy Ambassadors (AAA) program is a component of SOFIA's…

  20. An investigation of the optimization of parameters affecting the implementation of fourier transform spectroscopy at 20-500 micron from the C-141 airborne infrared observatory

    NASA Technical Reports Server (NTRS)

    Thompson, R. I.; Erickson, E. F.

    1976-01-01

    A program for 20-500 micron spectroscopy from the NASA flying C141 infrared observatory is being carried out with a Michelson interferometer. The parameters affecting the performance of the instrument are studied and an optimal configuration for high performance on the C-141 aircraft is recommended. As each parameter is discussed the relative merits of the two modes of mirror motion (rapid scan or step and integrate) are presented.

  1. SOFIA Project: SOFIA-Stratospheric Observatory for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Tseng, Ting

    2007-01-01

    A viewgraph presentation on the SOFIA project is shown. The topics include: 1) Aircraft Information; 2) Major Components of SOFIA; 3) Aircraft External View; 4) Airborne Observatory Layout; 5) Telescope Assembly; 6) Uncoated Primary Mirror; 7) Airborne Astronomy; 8) Requirements & Specifications; 9) Technical Challenges; 10) Observatory Operation; and 11) SOFIA Flight Test.

  2. Ionospheric research for space weather service support

    NASA Astrophysics Data System (ADS)

    Stanislawska, Iwona; Gulyaeva, Tamara; Dziak-Jankowska, Beata

    2016-07-01

    Knowledge of the behavior of the ionosphere is very important for space weather services. A wide variety of ground based and satellite existing and future systems (communications, radar, surveillance, intelligence gathering, satellite operation, etc) is affected by the ionosphere. There are the needs for reliable and efficient support for such systems against natural hazard and minimalization of the risk failure. The joint research Project on the 'Ionospheric Weather' of IZMIRAN and SRC PAS is aimed to provide on-line the ionospheric parameters characterizing the space weather in the ionosphere. It is devoted to science, techniques and to more application oriented areas of ionospheric investigation in order to support space weather services. The studies based on data mining philosophy increasing the knowledge of ionospheric physical properties, modelling capabilities and gain applications of various procedures in ionospheric monitoring and forecasting were concerned. In the framework of the joint Project the novel techniques for data analysis, the original system of the ionospheric disturbance indices and their implementation for the ionosphere and the ionospheric radio wave propagation are developed since 1997. Data of ionosonde measurements and results of their forecasting for the ionospheric observatories network, the regional maps and global ionospheric maps of total electron content from the navigational satellite system (GNSS) observations, the global maps of the F2 layer peak parameters (foF2, hmF2) and W-index of the ionospheric variability are provided at the web pages of SRC PAS and IZMIRAN. The data processing systems include analysis and forecast of geomagnetic indices ap and kp and new eta index applied for the ionosphere forecasting. For the first time in the world the new products of the W-index maps analysis are provided in Catalogues of the ionospheric storms and sub-storms and their association with the global geomagnetic Dst storms is

  3. Ionospheric Modelling using GPS to Calibrate the MWA. II: Regional Ionospheric Modelling using GPS and GLONASS to Estimate Ionospheric Gradients

    NASA Astrophysics Data System (ADS)

    Arora, B. S.; Morgan, J.; Ord, S. M.; Tingay, S. J.; Bell, M.; Callingham, J. R.; Dwarakanath, K. S.; For, B.-Q.; Hancock, P.; Hindson, L.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kapińska, A. D.; Lenc, E.; McKinley, B.; Offringa, A. R.; Procopio, P.; Staveley-Smith, L.; Wayth, R. B.; Wu, C.; Zheng, Q.

    2016-07-01

    We estimate spatial gradients in the ionosphere using the Global Positioning System and GLONASS (Russian global navigation system) observations, utilising data from multiple Global Positioning System stations in the vicinity of Murchison Radio-astronomy Observatory. In previous work, the ionosphere was characterised using a single-station to model the ionosphere as a single layer of fixed height and this was compared with ionospheric data derived from radio astronomy observations obtained from the Murchison Widefield Array. Having made improvements to our data quality (via cycle slip detection and repair) and incorporating data from the GLONASS system, we now present a multi-station approach. These two developments significantly improve our modelling of the ionosphere. We also explore the effects of a variable-height model. We conclude that modelling the small-scale features in the ionosphere that have been observed with the MWA will require a much denser network of Global Navigation Satellite System stations than is currently available at the Murchison Radio-astronomy Observatory.

  4. Integration of fuzzy logic and image analysis for the detection of gullies in the Calhoun critical zone observatory using airborne LiDAR data

    NASA Astrophysics Data System (ADS)

    Bastola, S.; Noto, L. V.; Dialynas, Y. G.; Bras, R. L.

    2015-12-01

    The entire Piedmont of the Southeastern United States, where the Calhoun Critical Zone Observatory (CCZO) is located, experienced one of the most severe erosive events in the United States during last two centuries. Forested areas were cleared to cultivate cotton, tobacco and other crops during the nineteenth and early twentieth century and these land use change, together with intense rainfalls, initiated deep gullying. An accurate mapping of these landforms is important since, despite some gully stabilization and reforestation efforts, gullies are still major contributors of sediment to streams. Mapping gullies in the CCZO area is hindered by the presence of dense canopy which precludes the identification through aerial photogrammetry and other traditional remote sensing methods. Moreover, the wide spatial extent of the gullies makes detailed field surveys, for the identification and characterization of entire gullies, a very large and expensive proposition. This work aims to develop and assess an automated set of algorithms to detect and map gullies using morphological characteristics retrieved by very high resolution imagery (VHRI). A one-meter resolution LiDAR DEM is used to derive different morphometric indices whose combination, carried out using spatial analysis methods and fuzzy logic rules, are a tool to identify gullies. This spatial model has been calibrated using the reference perimeters of two gullies that we measured during a recent field survey. The entire procedure attempts to provide estimates of gully erosion patterns, which characterize the entire Calhoun CZO area and to develop and evaluate a method to measure characteristic features of gullies (i.e. depth and volume).

  5. Ionospheric wave and irregularity measurements using passive radio astronomy techniques

    NASA Technical Reports Server (NTRS)

    Erickson, W. C.; Mahoney, M. J.; Jacobson, A. R.; Knowles, S. H.

    1988-01-01

    The observation of midlatitude structures using passive radio astronomy techniques is discussed, with particular attention being given to the low-frequency radio telescope at the Clark Lake Radio Observatory. The present telescope operates in the 10-125-MHz frequency range. Observations of the ionosphere at separations of a few kilometers to a few hundreds of kilometers by the lines of sight to sources are possible, allowing the determination of the amplitude, wavelength, direction of propagation, and propagation speed of ionospheric waves. Data are considered on large-scale ionospheric gradients and the two-dimensional shapes and sizes of ionospheric irregularities.

  6. Carnegie Observatories

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The Carnegie Observatories were founded in 1902 by George Ellery Hale. Their first facility was the MOUNT WILSON OBSERVATORY, located in the San Gabriel Mountains above Pasadena, California. Originally a solar observatory, it moved into stellar, galactic and extragalactic research with the construction of the 60 in (1.5 m), and 100 in (2.5 m) telescopes, each of which was the largest in the world...

  7. Stratospheric Observatory for Infrared Astronomy (SOFIA)

    NASA Astrophysics Data System (ADS)

    Savage, M. L.; Becklin, E. E.

    2015-09-01

    The joint U.S. and German Stratospheric Observatory for Infrared Astronomy (SOFIA), project has been operating airborne astronomy flights from Palmdale, California since 2011. The observatory consists of a modified 747sp aircraft with a 2.5meter telescope in the tail section. In addition to observing flights out of Palmdale, Ca. this airborne observatory has been able to take advantage of its mobility to observe in the southern hemisphere (New Zealand), to perform multi-wavelength observations of the Super Novae (SN 2014b) in 2014, and to intersect the track of a Pluto Occultation in the southern hemisphere just a few weeks prior to the New Horizons mission fly by of the planet in summer 2015. Science results, observatory operations, current instrument status and participation in future instrument developments, over the lifetime of the observatory will be discussed.

  8. Astronomical observatories

    NASA Technical Reports Server (NTRS)

    Ponomarev, D. N.

    1983-01-01

    The layout and equipment of astronomical observatories, the oldest scientific institutions of human society are discussed. The example of leading observatories of the USSR allows the reader to familiarize himself with both their modern counterparts, as well as the goals and problems on which astronomers are presently working.

  9. Coordinated airborne and satellite measurements of equatorial plasma depletions

    SciTech Connect

    Weber, E.J.; Brinton, H.C.; Buchau, J.; Moore, J.G.

    1982-12-01

    A series of experiments was conducted in December 1979 to investigate the structure of plasma depletions in the low latitude, nightime ionosphere. The measurements included all sky imaging photometer (ASIP), ionosonde and amplitude scintillation observations from the AFGL Airborne Ionospheric Observatory (AIO), and in situ ion density measurements from the Atmosphere Explorer (AE-E) Bennett Ion Mass Spectrometer (BIMS). The AIO performed two flights along the Ascension Island (-18/sup 0/ MLAT) magnetic meridian: one in the southern hemisphere and one near the Ascension conjugate point in the northern hemisphere. During these flights, measurements from the AE-E satellite at 434 km altitude are compared with simultaneous remote ionospheric measurements from the AIO. Density biteouts of approximately one order of magnitude in the dominant ion O/sup +/, were mapped to lower altitudes along magnetic field lines for comparison with 6300-A and 7774-A O I airglow depletions. Because of the different airglow production mechanisms (dissociative recombination of O/sup +//sub 2/ for 6300 A and radiative recombination of O/sup +/ for 7774 A) the 6300-A depletions reflect plasma depletions near the bottomside of the F layer, while those at 7774 A are located near the peak of the layer. The O/sup +/ biteouts map directly into the 7774-A airglow depletions in the same hemisphere and also when traced into the opposite hemisphere, which indicates magnetic flux tube alignment over north-south distances of approx.2220 km. The 6300-A (bottomside) depletions are wider in longitude than the 7774-A (F-peak) depletions near the equatorward edge of the Appleton anomaly. This difference in topside and bottomside structure is used to infer large-scale structure near the anomaly and to relate this to structure, commonly observed near the magnetic equator by the ALTAIR radar.

  10. Airborne Imagery Collections Barrow 2013

    DOE Data Explorer

    Cherry, Jessica; Crowder, Kerri

    2015-07-20

    The data here are orthomosaics, digital surface models (DSMs), and individual frames captured during low altitude airborne flights in 2013 at the Barrow Environmental Observatory. The orthomosaics, thermal IR mosaics, and DSMs were generated from the individual frames using Structure from Motion techniques.

  11. Tartu Observatory

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Tartu Observatory (TO) is a research institution in Estonia accommodating the northernmost 1.5 m telescope in the world. It is located in Estonia, about 20 km south-west of Tartu in the village of Tõravere (58°16'08''.4 N, 26°27'32''.4 E). TO performs research in astrophysics and atmospheric physics and popularizes those branches of science. TO was founded in 1808 as an observatory of Tartu Unive...

  12. Taosi Observatory

    NASA Astrophysics Data System (ADS)

    Sun, Xiaochun

    Taosi observatory is the remains of a structure discovered at the later Neolithic Taosi site located in Xiangfen County, Shanxi Province, in north-central China. The structure is a walled enclosure on a raised platform. Only rammed-earth foundations of the structure remained. Archaeoastronomical studies suggest that this structure functioned as an astronomical observatory. Historical circumstantial evidence suggests that it was probably related to the legendary kingdom of Yao from the twenty-first century BC.

  13. Radon measurements aboard the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Kritz, Mark A.; Rosner, Stefan W.

    1995-01-01

    We have carried out three (piggyback) radon-related projects aboard the KAO. The first, which was limited to upper tropospheric measurements while in level flight, revealed the systematic occurrence of unexpectedly high radon concentrations in this region of the atmosphere. The second project was an instrument development project, which led to the installation of an automatic radon measurement system aboard the NASA ER-2 High Altitude Research Aircraft. In the third, we installed a new system capable of collecting samples during the normal climb and descent of the KAO. The results obtained in these projects have resulted in significant contributions to our knowledge of atmospheric transport processes, and are currently playing a key role in the validation of global circulation and transport models.

  14. Ionosphere/microwave beam interaction study. [satellite solar energy conversion

    NASA Technical Reports Server (NTRS)

    Duncan, L. M.; Gordon, W. E.

    1977-01-01

    A solar power satellite microwave power density of 20mw sq cm was confirmed as the level where nonlinear interactions may occur in the ionosphere, particularly at 100 km altitude. Radio wave heating at this altitude, produced at the Arecibo Observatory, yielded negative results for radio wave heating of an underdense ionosphere. Overdense heating produced striations in the ionosphere which may cause severe radio frequency interference problems under certain conditions. The effects of thermal self-focusing are shown to be limited severely geographically. The aspect sensitivity of field-aligned striations makes interference-free regions above magnetic latitude about 60 deg. A test program is proposed to simulate the interaction of the SPS beam with the ionosphere, to measure the effects of the interaction on the ionosphere and on communication and navigation systems, and to interpret the results.

  15. SOFIA: Stratospheric Observatory for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Erickson, E. F.; Davidson, J. A.

    1993-01-01

    SOFIA, (Stratospheric Observatory for Infrared Astronomy) is a planned 2.5 meter telescope to be installed in a Boeing 747 aircraft and operated at altitudes from 41,000 to 46,000 feet. It will permit routine measurement of infrared radiation inaccessible from the ground-based sites, and observation of astronomical objects and transient events from anywhere in the world. The concept is based on 18 years of experience with NASA's Kuiper Airborne Observatory (KAO), which SOFIA would replace.

  16. Remote Sensing of Atmospheric and Ionospheric Signals Prior to the Mw 8.3 Illapel Earthquake, Chile 2015

    NASA Astrophysics Data System (ADS)

    Mansouri Daneshvar, Mohammad Reza; Freund, Friedemann T.

    2016-08-01

    In the present study, a number of atmospheric and some ionospheric anomalies are analyzed, which were recorded prior to the Mw 8.3 Illapel earthquake of September 16, 2015. This very large earthquake occurred in Central Chile, close to the coast, as the result of thrust faulting on the interface between the Nazca Plate and South American continent. Using remotely sensed data extracted from NASA/Giovanni, NOAA/NCEP, and NOAA/NGDC, atmospheric and ionospheric anomalies were observed that co-registered 35-40 and 25-30 days prior to the main shock, respectively. With reference to long-term time series over the epicentral area, significant atmospheric anomalies were recorded for cloud cover, geopotential height, precipitation rates, surface air pressure, omega, stream function, and wind vectors—all in the time window of August 5-10, 2015, 35-40 days prior to the main shock. Anomalous TEC maps were recorded for the same time period. Satellite images indicate the formation of an unusual cyclone, presumably triggered by air turbulences and abnormal atmospheric conditions over the epicentral area, including strong vertical winds. Data from the Jicamarca radio observatory in Peru, more than 2000 km to the North, reveal anomalous ionospheric variations on August 15-20, 2015 with respect to international reference ionosphere thickness parameters and the altitude of the F layer. The observed anomalies are consistent with processes that occur at the ground-to-air interface due to the stress activation of peroxy defects in the hypocentral volume. The flow of positive hole charge carriers to the Earth surface expected to have led to massive air ionization, generating at first primarily positive airborne ions, then negative air ions plus ozone. Understanding the sequence of processes inside the Earth's crust and at the ground-to-air interface provides information not previously available about the causal and temporal linkages between the various pre-earthquake phenomena and the

  17. Keele Observatory

    NASA Astrophysics Data System (ADS)

    Theodorus van Loon, Jacco; Albinson, James; Bagnall, Alan; Bryant, Lian; Caisley, Dave; Doody, Stephen; Johnson, Ian; Klimczak, Paul; Maddison, Ron; Robinson, StJohn; Stretch, Matthew; Webb, John

    2015-08-01

    Keele Observatory was founded by Dr. Ron Maddison in 1962, on the hill-top campus of Keele University in central England, hosting the 1876 Grubb 31cm refractor from Oxford Observatory. It since acquired a 61cm research reflector, a 15cm Halpha solar telescope and a range of other telescopes. Run by a group of volunteering engineers and students under directorship of a Keele astrophysicist, it is used for public outreach as well as research. About 4,000 people visit the observatory every year, including a large number of children. We present the facility, its history - including involvement in the 1919 Eddington solar eclipse expedition which proved Albert Einstein's theory of general relativity - and its ambitions to erect a radio telescope on its site.

  18. Physics of planetary ionospheres

    NASA Technical Reports Server (NTRS)

    Bauer, S. J.

    1973-01-01

    The fundamental physical and chemical processes in an idealized planetary ionosphere are considered as a general abstraction, with actual planetary ionospheres representing special cases. After describing the structure of the neutral atmospheres (the barosphere, the thermosphere, and the exosphere) and noting the principal ionizing radiations responsible for the formation of planetary ionospheres, a detailed study is made of the thermal structure of these ionospheres and of the chemical processes and plasma-transport processes occurring in them. The features of equilibrium and realistic models of planetary ionospheres are discussed, and an attempt is made to determine the extent of these ionospheres. Considering the ionosphere as a plasma, a plasma kinetic approach is developed for determining the effects of interactions between individual particles and waves in this plasma. The use of remote-sensing radio techniques and direct measurement or in situ techniques is discussed. Finally, the observed properties of the ionospheres of the Earth, Mars, Venus, and Jupiter are reviewed.

  19. WNCC Observatory

    NASA Astrophysics Data System (ADS)

    Snyder, L. F.

    2003-05-01

    Western Nevada Community College (WNCC), located in Carson City, Nevada, is a small two year college with only 6,000 students. Associate degrees and Cer- tificates of Achievement are awarded. The college was built and started classes in 1971 and about 12 years ago the chair of the physics department along with a few in administration had dreams of building a small observatory for education. Around that time a local foundation, Nevada Gaming Foundation for Education Excellence, was looking for a beneficiary in the education field to receive a grant. They decided an observatory at the college met their criteria. Grants to the foundation instigated by Senators, businesses, and Casinos and donations from the local public now total $1.3 million. This paper will explain the different facets of building the observatory, the planning, construction, telescopes and equipment decisions and how we think it will operate for the public, education and research. The organization of local volunteers to operate and maintain the observatory and the planned re- search will be explained.

  20. Photochemistry of planetary ionospheres

    NASA Technical Reports Server (NTRS)

    Nagy, Andrew F.

    1987-01-01

    The dominant photochemical reactions taking place in the ionospheres of Venus, Saturn, and Comet P/Halley are presented. It is shown that the differences in the ionospheres of these celestial bodies result from the different chemistry, energetics, and dynamics of the respective atmospheres. The role of photochemistry in the formation of the individual ionospheres is discussed.

  1. Ionospheric disturbances at the equatorial anomaly crest region during the March 1989 magnetic storms

    SciTech Connect

    Yinn-Nien Huang; Kang, Cheng )

    1991-08-01

    On March 6, 1989, the largest sunspot group since 1982 came into view as it moved out of the eastern limb of the Sun. It was highly active during March8-18, and a great many transient ionospheric and geomagnetic variations were triggered by this sunspot group. The intensive ionospheric observations at Lunping Observatory and Chungli Ionosphere Station during this period recorded 30 solar flares manifested as shortwave fade-outs, sudden frequency deviations, and solar flare effects and three storm sudden commencement (SSC)-tupe geomagnetic storms, among which the March 13 SSC-type geomagnetic storm triggered an unusually severe ionospheric disturbance. The ionospheric total electron content, the critical frequency of the F{sub 2} layer, f{sub o}F{sub 2}, and the virtual heights at given frequencies all show wavelike up-and-down oscillations of the ionosphere. This oscillatory ionospheric motion is explained as due to the compression and expansion of the plasmasphere.

  2. Ionospheric disturbances at the equatorial anomaly crest region during the March 1989 magnetic storms

    NASA Astrophysics Data System (ADS)

    1991-08-01

    On March 6, 1989, the largest sunspot group since 1982 came into view as it moved out of the eastern limb of the Sun. It was highly active during March 8-18, and a great many transient ionospheric and geomagnetic variations were triggered by this sunspot group. The intensive ionospheric observations at Lunping Observatory and Chungli Ionosphere Station during this period recorded 30 solar flares manifested as shortwave fade-outs, sudden frequency deviations, and solar flare effects and three storm sudden commencement (SSC)-type geomagnetic storms, among which the March 13 SSC-type geomagnetic storm triggered an unusually severe ionospheric disturbance. The ionospheric total electron content, the critical frequency of the F2 layer, f0F2, and the virtual heights at given frequencies all show wavelike up-and-down oscillations of the ionosphere. This oscillatory ionospheric motion is explained as due to the compression and expansion of the plasmasphere.

  3. Airborne Submillimeter Spectroscopy

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, J.

    1998-01-01

    This is the final technical report for NASA-Ames grant NAG2-1068 to Caltech, entitled "Airborne Submillimeter Spectroscopy", which extended over the period May 1, 1996 through January 31, 1998. The grant was funded by the NASA airborne astronomy program, during a period of time after the Kuiper Airborne Observatory was no longer operational. Instead. this funding program was intended to help develop instrument concepts and technology for the upcoming SOFIA (Stratospheric Observatory for Infrared Astronomy) project. SOFIA, which is funded by NASA and is now being carried out by a consortium lead by USRA (Universities Space Research Association), will be a 747 aircraft carrying a 2.5 meter diameter telescope. The purpose of our grant was to fund the ongoing development of sensitive heterodyne receivers for the submillimeter band (500-1200 GHz), using sensitive superconducting (SIS) detectors. In 1997 July we submitted a proposal to USRA to construct a heterodyne instrument for SOFIA. Our proposal was successful [1], and we are now continuing our airborne astronomy effort with funding from USRA. A secondary purpose of the NAG2-1068 grant was to continue the anaIN'sis of astronomical data collected with an earlier instrument which was flown on the NASA Kuiper Airborne Observatory (KAO). The KAO instrument and the astronomical studies which were carried out with it were supported primarily under another grant, NAG2-744, which extended over October 1, 1991 through Januarv 31, 1997. For a complete description of the astronomical data and its anailysis, we refer the reader to the final technical report for NAG2-744, which was submitted to NASA on December 1. 1997. Here we report on the SIS detector development effort for SOFIA carried out under NAG2-1068. The main result of this effort has been the demonstration of SIS mixers using a new superconducting material niobium titanium nitride (NbTiN), which promises to deliver dramatic improvements in sensitivity in the 700

  4. The Arecibo Observatory as an MST radar

    NASA Technical Reports Server (NTRS)

    Woodman, R. F.

    1983-01-01

    The radars and other systems at the Arecibo Observatory were designed and built, originally, for incoherent-scatter and radio-astronomy research. More recently, important additions have been made for planetary radar and artificial RF heating of the ionosphere. Although designed and built for a different application, these systems have shown to be very powerful tools for tropospheric, stratospheric and mesospheric research. The Observatory at present has two main radars: one at 430 and the other at 2380 MHz. In addition, 50-MHz MST radar work has been done using portable transmitters brought to the Observatory for this purpose. This capability will become permanent with the recent acquisition of a transmitter at this frequency. Furthermore, control and data processing systems have been developed to use the powerful HF transmitter and antennas of the HF-heating facility as an HF bistatic radar. A brief description of the four radars available at the Observatory is presented.

  5. Moon exploration: lunar radio observatory

    NASA Astrophysics Data System (ADS)

    Skalsky, Alexandre; Zelenyi, Lev; Rothkaehl, Hanna; Gurvits, Leonid; Sadovski, Andrei; Mogilevsky, Mikhail; Gotlib, Vladimir

    The Moon is an attractive base for fundamental scientific studies. The conducting ionosphere of Earth prevents propagation of radio emission coming from the outer space to the Earth’s surface at frequencies below a few MHz. In contrast, the Moon surrounded by a very thin atmosphere and ionosphere is a perfect site for an ultra-long-wavelength (ULW) facility for studies of cosmic radio emission at frequencies below the Earth’s ionosphere cut-off. This range of frequencies is the last unexplored window in the spectrum of the universe’s electromagnetic emission, The radio facility deployed on the Moon’s surface will be a multidisciplinary tool for addressing a wide range of scientific disciplines from cosmology to astrophysics to planetology, solar-terrestrial physics and geophysics. The Moon-based ULW observatory will be an experimental and observational facility for transformational science. One of the most intriguing objectives for the ULW science is a search for terrestrial-like planets in the exosolar systems, i.e. extra-solar planets possessing an intrinsic magnetic field and magnetospheres interacting with a stellar wind. Such the interaction generates radio emission similar to the Auroral Kilometric Radiation (AKR) of the terrestrial magnetosphere. The intrinsic magnetic field shielding the planetary surface from the cosmic radiation is one of the strong indicators of possible habitability of an exoplanet. ACKNOWLEDGMENTS: This work was supported by the PP RAS 22 grant.

  6. Grand Observatory

    NASA Technical Reports Server (NTRS)

    Young, Eric W.

    2002-01-01

    Various concepts have been recently presented for a 100 m class astronomical observatory. The science virtues of such an observatory are many: resolving planets orbiting around other stars, resolving the surface features of other stars, extending our temporal reach back toward the beginning (at and before stellar and galactic development), improving on the Next Generation Space Telescope, and other (perhaps as yet) undiscovered purposes. This observatory would be a general facility instrument with wide spectral range from at least the near ultraviolet to the mid infrared. The concept espoused here is based on a practical, modular design located in a place where temperatures remain (and instruments could operate) within several degrees of absolute zero with no shielding or cooling. This location is the bottom of a crater located near the north or south pole of the moon, most probably the South Polar Depression. In such a location the telescope would never see the sun or the earth, hence the profound cold and absence of stray light. The ideal nature of this location is elaborated herein. It is envisioned that this observatory would be assembled and maintained remotely through the use of expert robotic systems. A base station would be located above the crater rim with (at least occasional) direct line-of-sight access to the earth. Certainly it would be advantageous, but not absolutely essential, to have humans travel to the site to deal with unexpected contingencies. Further, observers and their teams could eventually travel there for extended observational campaigns. Educational activities, in general, could be furthered thru extended human presence. Even recreational visitors and long term habitation might follow.

  7. Stellar Occultations from Airborne Platforms: 1988 to 2016

    NASA Astrophysics Data System (ADS)

    Bosh, Amanda S.; Dunham, Edward W.; Zuluaga, Carlos; Levine, Stephen; Person, Michael J.; Van Cleve, Jeffrey E.

    2016-10-01

    Observing a stellar occultation by a solar system body with an airborne telescope requires precise positioning of the observer within the shadow cast onto the Earth. For small bodies like Pluto and Kuiper Belt objects, smaller than the Earth, the challenge is particularly intense, with the accuracy of the astrometric and flight planning determining whether the observation succeeds or fails. From our first airborne occultation by Pluto in 1988 aboard the Kuiper Airborne Observatory (KAO), to our most recent event by Pluto in 2015 aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA), we have refined our astrometric and flight planning systems to the point where we can now place an airborne observer into the small central flash zone. We will discuss the history of airborne observation of occultations while detailing the improvements in the astrometric processes. Support for this work was provided by NASA SSO grant NNX15AJ82G to Lowell Observatory.

  8. Ice Observatory

    NASA Astrophysics Data System (ADS)

    blugerman, n.

    2015-10-01

    My project is to make ice observatories to perceive astral movements as well as light phenomena in the shape of cosmic rays and heat, for example.I find the idea of creating an observation point in space, that in time will change shape and eventually disappear, in consonance with the way we humans have been approaching the exploration of the universe since we started doing it. The transformation in the elements we use to understand big and small transformations, within the universe elements.

  9. Mesoscale ionospheric tomography at the Auroral region

    NASA Astrophysics Data System (ADS)

    Luntama, J.; Kokkatil, G. V.

    2008-12-01

    FMI (Finnish Meteorological Institute) has used observations from the dense GNSS network in Finland for high resolution regional ionospheric tomography. The observation system used in this work is the VRS (Virtual Reference Station) network in Finland operated by Geotrim Ltd. This network contains 86 GNSS ground stations providing two frequency GPS and GLONASS observations with the sampling rate of 1 Hz. The network covers the whole Finland and the sampling of the ionosphere is very good for observing mesoscale ionospheric structures at the Auroral region. The ionospheric tomography software used by FMI is the MIDAS (Multi-Instrument Data Analysis System) algorithm developed and implemented by the University of Bath (Mitchell and Spencer, 2003). MIDAS is a 3-D extension of the 2-D tomography algorithm originally presented by Fremouw et al. (1992). The research at FMI is based on ground based GNSS data collected in December 2006. The impacts of the two geomagnetic storms during the month are clearly visible in the retrieved electron density and TEC maps and they can be correlated with the magnetic field disturbances measured by the IMAGE magnetometer network. This is the first time that mesoscale structures in the ionospheric plasma can be detected from ground based GNSS observations at the Auroral region. The continuous high rate observation data from the Geotrim network allows monitoring of the temporal evolution of these structures throughout the storms. Validation of the high resolution electron density and TEC maps is a challenge as independent reference observations with a similar resolution are not available. FMI has compared the 3-D electron density maps against the 2-D electron density plots retrieved from the observations from the Ionospheric Tomography Chain operated by the Sodankylä Geophysical Observatory (SGO). Additional validation has been performed with intercomparisons with observations from the ground based magnetometer and auroral camera network

  10. Ionospheric research opportunity

    NASA Astrophysics Data System (ADS)

    Rickel, Dwight

    1985-05-01

    Ground-based explosions have been exploited successfully in the past as a relatively controlled source for producing ionospheric disturbances. On June 25, the Defense Nuclear Agency will conduct a high explosives test on the northern section of the White Sands Missile Range. Approximately 4,800 tons of ammonium nitrate and fuel oil (ANFO) will be detonated at ground level, producing an acoustic shock wave with a surface pressure change of approximately 20 mbar at a 6 km range. This shock front will have sufficient strength to propagate into the ionosphere with at least a 10% change in the ambient pressure across the disturbance front in the lower F region. Such an ionospheric perturbation will give ionospheric researchers an excellent opportunity to investigate acoustic propagation at ionospheric heights, shock dissipation effect, the ion-neutral coupling process, acoustic-gravity wave (traveling ionospheric disturbance) generation mechanisms, and associated RF phenomena.

  11. Stratospheric Observatory for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Becklin, Eric E.

    2001-01-01

    The joint U.S. and German SOFIA project to develop and operate a 2.5-meter infrared airborne telescope in a Boeing 747-SP is now well into development. First science flights will begin in 2004 with 20% of the observing time assigned to German investigators. The observatory is expected to operate for over 20 years. The sensitivity, characteristics and science instrument complement are discussed. Present and future instrumentation will allow unique astrobiology experiments to be carried out. Several experiments related to organic molecules in space will be discussed.

  12. Airborne Transparencies.

    ERIC Educational Resources Information Center

    Horne, Lois Thommason

    1984-01-01

    Starting from a science project on flight, art students discussed and investigated various means of moving in space. Then they made acetate illustrations which could be used as transparencies. The projection phenomenon made the illustrations look airborne. (CS)

  13. 150 years of magnetic observatories: Recent researches on world data

    NASA Astrophysics Data System (ADS)

    Barraclough, D. R.; Clark, T. D. G.; Cowley, S. W. H.; Hibberd, F. H.; Hide, R.; Kerridge, D. J.; Lowes, F. J.; Malin, S. R. C.; Murphy, T.; Rishbeth, H.; Runcorn, S. K.; Soffel, H. C.; Stewart, D. N.; Stuart, W. F.; Whaler, K. A.; Winch, D. E.

    1992-01-01

    A joint Discussion Meeting of the Royal Astronomical Society and the Royal Irish Academy, held on January 11th, 1991, commemorated the establishment of some early magnetic observatories, discussed recent research using global geomagnetic data and described the present status of magnetic observatories in the United Kingdom. The observatory and instruments at the Dublin magnetic observatory; the origins of the Greenwich magnetic observatory, and why it eventually had to be resited; and the history of the Munich magnetic observatory formed the historical part of the proceedings. Current research topics discussed were the geomagnetic secular variation and deep Earth structure and dynamics; fluid flow patterns near the top of the core; the origin of the annual variation of the geomagnetic field; results of an analysis of monthly means from some British observatories; a new theory of the geomagnetic daily variation; and the interactions between ionospheric science and geomagnetism. The present-day observatory scene was described in terms of the information that can be derived from the almost 40 year series of data from Hartland magnetic observatory; of the methods used to process data from the three UK magnetic observatories, which nowadays are operated automatically and remotely; and (a look into the future) of a new project, INTERMAGNET, which aims to make available, in near real time, data from the world-wide network of magnetic observatories.

  14. International reference ionosphere 1990

    NASA Technical Reports Server (NTRS)

    Bilitza, Dieter; Rawer, K.; Bossy, L.; Kutiev, I.; Oyama, K.-I.; Leitinger, R.; Kazimirovsky, E.

    1990-01-01

    The International Reference Ionosphere 1990 (IRI-90) is described. IRI described monthly averages of the electron density, electron temperature, ion temperature, and ion composition in the altitude range from 50 to 1000 km for magnetically quiet conditions in the non-auroral ionosphere. The most important improvements and new developments are summarized.

  15. Haystack Observatory

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Radio astronomy programs comprise three very-long-baseline interferometer projects, ten spectral line investigations, one continuum mapping in the 0.8 cm region, and one monitoring of variable sources. A low-noise mixer was used in mapping observations of 3C273 at 31 GHz and in detecting of a new methyl alcohol line at 36,169 MHz in Sgr B2. The new Mark 2 VLBI recording terminal was used in galactic H2O source observations using Haystack and the Crimean Observatory, USSR. One feature in W29 appears to have a diameter of 0.3 millisec of arc and a brightness temperature of 1.4 x 10 to the 15th power K. Geodetic baseline measurements via VLBI between Green Bank and Haystack are mutually consistent within a few meters. Radar investigations of Mercury, Venus, Mars, and the Moon have continued. The favorable opposition of Mars and improvements in the radar permit measurements on a number of topographic features with unprecedented accuracy, including scarps and crater walls. The floor of Mare Serenitatis slopes upward towards the northeast and is also the location of a strong gravitational anomaly.

  16. HELIO: The Heliophysics Integrated Observatory

    NASA Technical Reports Server (NTRS)

    Bentley, R. D.; Csillaghy, A.; Aboudarham, J.; Jacquey, C.; Hapgood, M. A.; Bocchialini, K.; Messerotti, M.; Brooke, J.; Gallagher, P.; Fox, P.; Hurlburt, N.; Roberts, D. A.; Sanchez Duarte, L.

    2011-01-01

    Heliophysics is a new research field that explores the Sun-Solar System Connection; it requires the joint exploitation of solar, heliospheric, magnetospheric and ionospheric observations. HELIO, the Heliophysics Integrated Observatory, will facilitate this study by creating an integrated e-Infrastructure that has no equivalent anywhere else. It will be a key component of a worldwide effort to integrate heliophysics data and will coordinate closely with international organizations to exploit synergies with complementary domains. HELIO was proposed under a Research Infrastructure call in the Capacities Programme of the European Commission's 7th Framework Programme (FP7). The project was selected for negotiation in January 2009; following a successful conclusion to these, the project started on 1 June 2009 and will last for 36 months.

  17. SOFIA: The Stratospheric Observatory For Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Hildebrand, Roger H.; Davidson, Jacqueline A.

    1990-01-01

    SOFIA, an airborne observatory intended to be carried aboard a Boeing 747 high performance aircraft, is described. The observatory is predicted to provide a threefold greater aperture than that of the Kuiper telescope. The Boeing aircraft will carry the 2.5 diameter telescope and its observers to altitudes of 14,000 and above where the atmosphere is very nearly transparent at all wavelengths. Various aspects and specific missions of the SOFIA project, a cooperative venture of the U.S. and Germany, are described.

  18. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the workshop was on how the airborne community can assist in achieving the goals of the Global Change Research Program. The many activities that employ airborne platforms and sensors were discussed: platforms and instrument development; airborne oceanography; lidar research; SAR measurements; Doppler radar; laser measurements; cloud physics; airborne experiments; airborne microwave measurements; and airborne data collection.

  19. Tropical Cyclone - Equatorial Ionosphere Coupling: A Statistical Study

    NASA Astrophysics Data System (ADS)

    Bhagavathiammal, G. J.

    2016-07-01

    This paper describes the equatorial ionosphere response to tropical cyclone events which was observed over the Indian Ocean. This statistical study tries to reveal the possible Tropical Cyclone (TC) - Ionosphere coupling. Tropical cyclone track and data can be obtained from the India Meteorological Department, New Delhi. Digisonde/Ionosonde data for the equatorial latitudes can be obtained from Global Ionospheric Radio Observatory. It is believed that TC induced convection as the driving agent for the increased gravity wave activity in the lower atmosphere and these propagating gravity waves deposit their energy and momentum into the upper atmosphere as Travelling Ionospheric Disturbances (TIDs). The convective regions are identified with the help of Outgoing Long wave radiation (OLR) data from NOAA Climate Data Center/ Precipitation data from TRMM Statellite. The variability of ionospheric parameter like Total Electron Content (TEC), foF2, h'F2 and Drift velocity are examined during TC periods. This study will report the possibility of TC-Ionosphere Coupling in equatorial atmosphere.

  20. Airborne Imagery

    NASA Technical Reports Server (NTRS)

    1983-01-01

    ATM (Airborne Thematic Mapper) was developed for NSTL (National Space Technology Companies) by Daedalus Company. It offers expanded capabilities for timely, accurate and cost effective identification of areas with prospecting potential. A related system is TIMS, Thermal Infrared Multispectral Scanner. Originating from Landsat 4, it is also used for agricultural studies, etc.

  1. Ionospheric irregularity physics modelling

    SciTech Connect

    Ossakow, S.L.; Keskinen, M.J.; Zalesak, S.T.

    1982-01-01

    Theoretical and numerical simulation techniques have been employed to study ionospheric F region plasma cloud striation phenomena, equatorial spread F phenomena, and high latitude diffuse auroral F region irregularity phenomena. Each of these phenomena can cause scintillation effects. The results and ideas from these studies are state-of-the-art, agree well with experimental observations, and have induced experimentalists to look for theoretically predicted results. One conclusion that can be drawn from these studies is that ionospheric irregularity phenomena can be modelled from a first principles physics point of view. Theoretical and numerical simulation results from the aforementioned ionospheric irregularity areas will be presented.

  2. Modeling Ionospheric Electrodynamics (Invited)

    NASA Astrophysics Data System (ADS)

    Huba, J. D.

    2009-12-01

    We present modeling results of ionospheric electrodynamics using the 3D NRL ionosphere model SAMI3. Recently, SAMI3 has been upgraded to solve the potential equation that determines the electrostatic potential from the ionospheric conductances (Pedersen and Hall) and drivers: neutral wind, gravity, and parallel current systems. We present results showing the impact of different neutral wind models (e.g., HWM93, HWM07, TIMEGCM) on the dynamics of the low- to mid-latitude ionosphere, as well as the Region 1 and 2 current systems. We point out issues and concerns with obtaining an accurate specification of the global electric field within the context of existing models.(with J. Krall, G. Joyce, S. Slinker, and G. Crowley). Research supported by NASA and ONR

  3. Ionospheric imaging using merged ultraviolet airglow and radio occultation data

    NASA Astrophysics Data System (ADS)

    Stephan, Andrew W.; Budzien, Scott A.; Finn, Susanna C.; Cook, Timothy A.; Chakrabarti, Supriya; Powell, Steven P.; Psiaki, Mark L.

    2014-09-01

    The Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) and GPS Radio Occultation and Ultraviolet Photometry-Colocated (GROUP-C) experiments are being considered for flight aboard the Space Test Program Houston 5 (STP-H5) experiment pallet to the International Space Station (ISS). LITES is a compact imaging spectrograph that makes one-dimensional images of atmospheric and ionospheric ultraviolet (60-140 nm) airglow above the limb of the Earth. The LITES optical design is advantageous in that it uses a toroidal grating as its lone optical surface to create these high-sensitivity images without the need for any moving parts. GROUP-C consists of two instruments: a nadir-viewing ultraviolet photometer that measures nighttime ionospheric airglow at 135.6 nm with unprecedented sensitivity, and a GPS receiver that measures ionospheric electron content and scintillation with the assistance of a novel antenna array designed for multipath mitigation. By flying together, these two experiments form an ionospheric observatory aboard the ISS that will provide new capability to study low- and mid-latitude ionospheric structures on a global scale. This paper presents the design and implementation of the LITES and GROUP-C experiments on the STP-H5 payload that will combine for the first time high-sensitivity in-track photometry with vertical spectrographic imagery of ionospheric airglow to create high-fidelity images of ionospheric structures. The addition of the GPS radio occultation measurement provides the unique opportunity to constrain, as well as cross-validate, the merged airglow measurements.

  4. Dayside Ionospheric Superfountain

    NASA Technical Reports Server (NTRS)

    Tsurutani, Bruce T.; Verkhoglyadova, Olga P.; Mannucci, Anthony J.

    2010-01-01

    The Dayside Ionospheric Super-fountain modified SAMI2 code predicts the uplift, given storm-time electric fields, of the dayside near-equatorial ionosphere to heights of over 800 kilometers during magnetic storm intervals. This software is a simple 2D code developed over many years at the Naval Research Laboratory, and has importance relating to accuracy of GPS positioning, and for satellite drag.

  5. Tsunami Ionospheric warning and Ionospheric seismology

    NASA Astrophysics Data System (ADS)

    Lognonne, Philippe; Rolland, Lucie; Rakoto, Virgile; Coisson, Pierdavide; Occhipinti, Giovanni; Larmat, Carene; Walwer, Damien; Astafyeva, Elvira; Hebert, Helene; Okal, Emile; Makela, Jonathan

    2014-05-01

    The last decade demonstrated that seismic waves and tsunamis are coupled to the ionosphere. Observations of Total Electron Content (TEC) and airglow perturbations of unique quality and amplitude were made during the Tohoku, 2011 giant Japan quake, and observations of much lower tsunamis down to a few cm in sea uplift are now routinely done, including for the Kuril 2006, Samoa 2009, Chili 2010, Haida Gwai 2012 tsunamis. This new branch of seismology is now mature enough to tackle the new challenge associated to the inversion of these data, with either the goal to provide from these data maps or profile of the earth surface vertical displacement (and therefore crucial information for tsunami warning system) or inversion, with ground and ionospheric data set, of the various parameters (atmospheric sound speed, viscosity, collision frequencies) controlling the coupling between the surface, lower atmosphere and the ionosphere. We first present the state of the art in the modeling of the tsunami-atmospheric coupling, including in terms of slight perturbation in the tsunami phase and group velocity and dependance of the coupling strength with local time, ocean depth and season. We then show the confrontation of modelled signals with observations. For tsunami, this is made with the different type of measurement having proven ionospheric tsunami detection over the last 5 years (ground and space GPS, Airglow), while we focus on GPS and GOCE observation for seismic waves. These observation systems allowed to track the propagation of the signal from the ground (with GPS and seismometers) to the neutral atmosphere (with infrasound sensors and GOCE drag measurement) to the ionosphere (with GPS TEC and airglow among other ionospheric sounding techniques). Modelling with different techniques (normal modes, spectral element methods, finite differences) are used and shown. While the fits of the waveform are generally very good, we analyse the differences and draw direction of future

  6. Multi-Instrument Observations of an MSTID over Arecibo Observatory

    NASA Technical Reports Server (NTRS)

    Klenzing, J. H.; Seker, I.; Pfaff, R. F.; Rowland, D. E.; Fung, S. F.; Mathews, J. D.

    2011-01-01

    The Penn State All-Sky Imager (PSASI) at Arecibo Observatory provides planar horizontal context to the vertical ionospheric profiles obtained by the Incoherent Seatter Radar (TSR). Electric field measurements from the Communication/Navigation Outage Forecast System (C/NOFS) satellite are mapped down geomagnetic field lines to the height of the airglow layer; allowing multi-instrument studies of field-aligned irregularities with radar, imager, and satellite. A Medium-Scale Traveling Ionospheric Disturbance (MSTID) was observed during such a conjunction near the December solstice of 2009.

  7. An MF/HF radio array for radio and radar imaging of the ionosphere

    NASA Astrophysics Data System (ADS)

    Isham, Brett; Gustavsson, Bjorn; Belyey, Vasyl; Bullett, Terrence

    2016-07-01

    The Aguadilla Radio Array will be installed at the Interamerican University Aguadilla Campus, located in northwestern Puerto Rico. The array is intended for broad-band medium and high-frequency (MF/HF, roughly 2 to 25 MHz) radio and bistatic radar observations of the ionosphere. The main array consists of 20 antenna elements, arranged in a semi-random pattern providing a good distribution of baseline vectors, with 6-meter minimum spacing to eliminate spacial aliasing. A relocatable 6-element array is also being developed, in which each element consists of a crossed pair of active electric dipoles and all associated electronics for phase-coherent radio measurements. A primary scientific goal of the array is to create images of the region of ionospheric radio emissions stimulated by the new Arecibo Observatory high-power high-frequency radio transmitter. A second primary goal is the study of ionospheric structure and dynamics via coherent radar imaging of the ionosphere in collaboration with the University of Colorado / NOAA Versatile Interferometric Pulsed Ionospheric Radar (VIPIR), located at the USGS San Juan Observatory in Cayey, Puerto Rico. In addition to ionospheric research in collaboration with the Cayey and Arecibo Observatories, the goals of the project include the development of radio sounding, polarization, interferometry, and imaging techniques, and training of students at the university and high school levels.

  8. SOFIA: Stratospheric Observatory For Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Kunz, Nans; Bowers, Al

    2007-01-01

    This viewgraph presentation reviews the great astronomical observatories both space and land based that are now operational. It shows the history of the development of SOFIA, from its conception in 1986 through the contract awards in 1996 and through the planned first flight in 2007. The major components of the observatory are shown and there is a comparison of the SOFIA with the Kuiper Airborne Observatory (KAO), which is the direct predecessor to SOFIA. The development of the aft ramp of the KAO was developed as a result of the wind tunnel tests performed for SOFIA development. Further slides show the airborne observatory layout and the telescope's optical layout. Included are also vies of the 2.5 Meter effective aperture, and the major telescope's components. The presentations reviews the technical challenges encountered during the development of SOFIA. There are also slides that review the wind tunnel tests, and CFD modeling performed during the development of SOFIA. Closing views show many views of the airplane, and views of SOFIA.

  9. The Boulder magnetic observatory

    USGS Publications Warehouse

    Love, Jeffrey J.; Finn, Carol A.; Pedrie, Kolby L.; Blum, Cletus C.

    2015-08-14

    The Boulder magnetic observatory has, since 1963, been operated by the Geomagnetism Program of the U.S. Geological Survey in accordance with Bureau and national priorities. Data from the observatory are used for a wide variety of scientific purposes, both pure and applied. The observatory also supports developmental projects within the Geomagnetism Program and collaborative projects with allied geophysical agencies.

  10. Ionospheric storms on Mars

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.; Woch, J.; Duru, F.; Gurnett, D.; Modolo, R.; Barabash, S.; Lundin, R.

    2009-04-01

    Measurements made by the ASPERA-3 and MARSIS experiments on Mars Express have shown that space weather effects related to the impact of a dense and high pressure solar wind on Mars cause strong perturbations in the martian induced magnetosphere and ionosphere. The magnetic barrier formed by pile-up of the draped interplanetary magnetic field ceases to be a shield for the incoming solar wind. Large blobs of solar wind plasma penetrate to the magnetosphere and sweep out dense plasma from the ionosphere. The topside martian ionosphere becomes very fragmented consisting of intermittent cold/low energy and energized plasmas. The scavenging effect caused by the intrusions of solar wind plasma clouds enhances significantly the losses of volatile material from Mars.

  11. The Arecibo Observatory Visitor and Educational Facility

    NASA Astrophysics Data System (ADS)

    Altschuler, Daniel R.

    1994-12-01

    As the world's largest single-dish radio telescope, Arecibo Observatory in Puerto Rico attracts thousands of visitors each year of all ages and from many countries. Pride in the Observatory has caused local Puerto Rican organizations to contribute the funds necessary for the construction of the new Arecibo Observatory Visitor and Educational Facility (AOVEF). Funds to develop the exhibits were obtained through a grant from the National Science Foundation. The Observatory is the main facility of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation. The AOVEF consists of approximately 9,000 square feet of building and outdoor program space. It will house about 3500 square feet of exhibits, a 100 person multi-purpose theater, a science merchandise store and appropriate meeting rooms and workspace. We expect to be able to begin construction in early 1995. Based on current experience, we anticipate that half of the expected 100,000 visitors per year will be school children brought by buses from their schools and half will be families and individuals, coming for a visit on their own. Details about our project and a discussion of the contents of the exhibitions which are being prepared will be presented.

  12. Characterizing Extreme Ionospheric Storms

    NASA Astrophysics Data System (ADS)

    Sparks, L.; Komjathy, A.; Altshuler, E.

    2011-12-01

    Ionospheric storms consist of disturbances of the upper atmosphere that generate regions of enhanced electron density typically lasting several hours. Depending upon the storm magnitude, gradients in electron density can sometimes become large and highly localized. The existence of such localized, dense irregularities is a major source of positioning error for users of the Global Positioning System (GPS). Consequently, satellite-based augmentation systems have been implemented to improve the accuracy and to ensure the integrity of user position estimates derived from GPS measurements. Large-scale irregularities generally do not pose a serious threat to estimate integrity as they can be readily detected by such systems. Of greater concern, however, are highly localized irregularities that interfere with the propagation of a signal detected by a user measurement but are poorly sampled by the receivers in the system network. The most challenging conditions have been found to arise following disturbances of large magnitude that occur only rarely over the course of a solar cycle. These extremely disturbed conditions exhibit behavior distinct from moderately disturbed conditions and, hence, have been designated "extreme storms". In this paper we examine and compare the behavior of the extreme ionospheric storms of solar cycle 23 (or, more precisely, extreme storms occurring between January 1, 2000, and December 31, 2008), as represented in maps of vertical total electron content. To identify these storms, we present a robust means of quantifying the regional magnitude of an ionospheric storm. Ionospheric storms are observed frequently to occur in conjunction with magnetic storms, i.e., periods of geophysical activity as measured by magnetometers. While various geomagnetic indices, such as the disturbance storm time (Dst) and the planetary Kp index, have long been used to rank the magnitudes of distinct magnetic storms, no comparable, generally recognized index exists for

  13. GROUP-C and LITES Experiments for Ionospheric Remote Sensing aboard the ISS

    NASA Astrophysics Data System (ADS)

    Budzien, S. A.; Stephan, A. W.; Chakrabarti, S.

    2013-12-01

    Ionospheric irregularities, also known as ionospheric bubbles, are transient features of the low and middle latitude ionosphere with important implications for operational systems. Understanding irregularity formation, development, and evolution is vital for efforts within NASA and DoD to forecast scintillation. Irregularity structures have been studied primarily using ground-based systems, though some spaced-based remote and in-situ sensing has been performed. An ionospheric observatory aboard the International Space Station (ISS) would provide new capability to study low- and mid-latitude ionospheric structures on a global scale. The GPS Radio Occultation and Ultraviolet Photometry Colocated (GROUPC) and the Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) experiments are being considered for flight aboard the Space Test Program Houston 5 (STP-H5) experiment pallet. By combining for the first time high-sensitivity in-track photometry with vertical ionospheric airglow spectrographic imagery, we demonstrate that high-fidelity optical tomographic reconstruction of bubbles can be performed from the ISS. Ground-based imagery can supplement the tomography by providing all-sky images of ionospheric structures (e.g. bubbles and TIDs) and of signatures of lower atmospheric dynamics, such as gravity waves, that may play a role in irregularity formation. The optical instrumentation can be augmented with additional sensors to provide measurements of scintillation and in situ plasma density, composition, and drifts.

  14. The NASA Airborne Astronomy Program: A perspective on its contributions to science, technology, and education

    NASA Technical Reports Server (NTRS)

    Larson, Harold P.

    1995-01-01

    The scientific, educational, and instrumental contributions from NASA's airborne observatories are deduced from the program's publication record (789 citations, excluding abstracts, involving 580 authors at 128 institutions in the United States and abroad between 1967-1990).

  15. Saturn's ionosphere and plasmasphere

    NASA Astrophysics Data System (ADS)

    Moore, Luke Edward

    2008-01-01

    A number of puzzling phenomena were revealed when the Voyager spacecraft flew past Saturn in 1981 to measure the ionized portions (ionosphere) of its upper atmosphere (thermosphere). Most of these issues have remained unexplained in the intervening 25 years due to a lack of conclusive observational data. With the arrival of Cassini at Saturn in July 2004, however, a new era of observations began, providing the promise of fresh evidence and demanding the development of a contemporary theoretical framework in order to re-examine old mysteries and understand new discoveries. This dissertation presents studies of Saturn's ionosphere and inner plasmasphere based on new time-dependent photochemical and diffusive transport models that solve the ion equations of continuity in one dimension. Calculations are conducted within the overall framework of a self-consistent, three-dimensional general circulation model (GCM) of Saturn's thermosphere, and the results of these studies are combined with GCM results to provide the building blocks of a new comprehensive model, the Saturn-Thermosphere- Ionosphere-Model (STIM). The one-dimensional model calculations are used to constrain and investigate a number of unresolved issues and to make testable predictions based on those investigations. Five primary topics are addressed: (1) the additional loss processes required to bring predicted electron densities into agreement with observations, (2) the discrepancy between theory and observations regarding the diurnal variation of peak electron density, (3) the effects of shadowing by Saturn's rings on its ionosphere, (4) the yet unknown electron and ion temperatures at Saturn, and (5) the ionospheric contribution to Saturn's plasmasphere. The models show that a steady influx of water into Saturn's atmosphere--from its rings or icy satellites--is required to explain observed electron densities. Additionally, the time-variability of the water source may be the cause of frequently observed

  16. NASA's Airborne Astronomy Program - Lessons For SOFIA

    NASA Astrophysics Data System (ADS)

    Erickson, Edwin F.

    2007-07-01

    Airborne astronomy was pioneered and has evolved at NASA Ames Research Center near San Francisco, California, since 1965. Nowhere else in the world has a similar program been implemented. Its many unique features deserve description, especially for the benefit of planning the operation of SOFIA, the Stratospheric Observatory for Infrared Astronomy, and in particular since NASA Headquarters’ recent decision to base SOFIA operations at Dryden Flight Research Center at Edwards, California instead of at Ames. The history of Ames’ airborne astronomy program is briefly summarized. Discussed in more detail are the operations and organization of the 21-year Kuiper Airborne Observatory (KAO) program, which provide important lessons for SOFIA. The KAO program is our best prototype for planning effective SOFIA operations. Principal features of the KAO program which should be retained on SOFIA are: unique science, innovative new science instruments and technologies, training of young scientists, an effective education and public outreach program, flexibility, continuous improvement, and efficient operations with a lean, well integrated team. KAO program features which should be improved upon with SOFIA are: (1) a management structure that is dedicated primarily to safely maximizing scientific productivity for the resources available, headed by a scientist who is the observatory director, and (2) stimuli to assure prompt distribution and accessibility of data to the scientific community. These and other recommendations were recorded by the SOFIA Science Working Group in 1995, when the KAO was decommissioned to start work on SOFIA. Further operational and organizational factors contributing to the success of the KAO program are described. Their incorporation into SOFIA operations will help assure the success of this new airborne observatory. SOFIA is supported by NASA in the U.S. and DLR (the German Aerospace Center) in Germany.

  17. Ionospheric Scintillation Explorer (ISX)

    NASA Astrophysics Data System (ADS)

    Iuliano, J.; Bahcivan, H.

    2015-12-01

    NSF has recently selected Ionospheric Scintillation Explorer (ISX), a 3U Cubesat mission to explore the three-dimensional structure of scintillation-scale ionospheric irregularities associated with Equatorial Spread F (ESF). ISX is a collaborative effort between SRI International and Cal Poly. This project addresses the science question: To what distance along a flux tube does an irregularity of certain transverse-scale extend? It has been difficult to measure the magnetic field-alignment of scintillation-scale turbulent structures because of the difficulty of sampling a flux tube at multiple locations within a short time. This measurement is now possible due to the worldwide transition to DTV, which presents unique signals of opportunity for remote sensing of ionospheric irregularities from numerous vantage points. DTV spectra, in various formats, contain phase-stable, narrowband pilot carrier components that are transmitted simultaneously. A 4-channel radar receiver will simultaneously record up to 4 spatially separated transmissions from the ground. Correlations of amplitude and phase scintillation patterns corresponding to multiple points on the same flux tube will be a measure of the spatial extent of the structures along the magnetic field. A subset of geometries where two or more transmitters are aligned with the orbital path will be used to infer the temporal development of the structures. ISX has the following broad impact. Scintillation of space-based radio signals is a space weather problem that is intensively studied. ISX is a step toward a CubeSat constellation to monitor worldwide TEC variations and radio wave distortions on thousands of ionospheric paths. Furthermore, the rapid sampling along spacecraft orbits provides a unique dataset to deterministically reconstruct ionospheric irregularities at scintillation-scale resolution using diffraction radio tomography, a technique that enables prediction of scintillations at other radio frequencies, and

  18. HAARP-based Investigations of Lightning-induced Nonlinearities within the D-Region Ionosphere

    NASA Astrophysics Data System (ADS)

    Moore, R. C.

    2015-12-01

    It is well-documented that energetic lightning can produce fantastical events with the lower ionosphere. Although the High-frequency Active Auroral Research Program (HAARP) transmitter is not as powerful as lightning, it can be used to investigate the nonlinear interactions that occur within the lower ionosphere, many of which also occur during lightning-induced ionospheric events. This paper presents the best experimental results obtained during D-region modification experiments performed by the University of Florida at the HAARP observatory between 2007 and 2014, including ELF/VLF wave generation experiments, wave-wave mixing experiments, and cross-modulation experiments. We emphasize the physical processes important for lightning-ionosphere interactions that can be directly investigated using HAARP.

  19. The Little Thompson Observatory

    NASA Astrophysics Data System (ADS)

    Schweitzer, A.; Melsheimer, T.; Rideout, C.; Vanlew, K.

    1998-12-01

    The Little Thompson Observatory is believed to be the first observatory built as part of a high school and accessible to other schools remotely, via the Internet. This observatory is the second member of the Telescopes in Education (TIE) project. Construction is nearly completed and first light is planned for fall 1998. The observatory is located on the grounds of Berthoud High School in northern Colorado. Local schools and youth organizations will have prioritized access to the telescope, and there will also be opportunities for public viewing. After midnight, the telescope will be open to world-wide use by schools via the Internet following the model of the first TIE observatory, the 24" telescope on Mt. Wilson. That telescope has been in use for the past four years by up to 50 schools per month. Students remotely connect to the observatory over the Internet, and then receive the images on their local computers. The observatory grew out of grassroots support from the local community surrounding Berthoud, Colorado, a town of 3,500 residents. TIE has provided the observatory with a Tinsley 18" Cassegrain telescope on a 10-year loan. The facility has been built with tremendous support from volunteers and the local school district. We have applied for an IDEAS grant to provide teacher training workshops which will allow K-12 schools in northern Colorado to make use of the Little Thompson Observatory, including remote observing from classrooms.

  20. The Little Thompson Observatory

    NASA Astrophysics Data System (ADS)

    Schweitzer, A.; Melsheimer, T.; Sackett, C.

    1999-05-01

    The Little Thompson Observatory is believed to be the first observatory built as part of a high school and accessible to other schools remotely, via the Internet. This observatory is the second member of the Telescopes in Education (TIE) project. Construction of the building and dome has been completed, and first light is planned for spring 1999. The observatory is located on the grounds of Berthoud High School in northern Colorado. Local schools and youth organizations will have prioritized access to the telescope, and there will also be opportunities for public viewing. After midnight, the telescope will be open to world-wide use by schools via the Internet following the model of the first TIE observatory, the 24" telescope on Mt. Wilson. Students remotely connect to the observatory over the Internet, and then receive the images on their local computers. The observatory grew out of grassroots support from the local community surrounding Berthoud, Colorado, a town of 3,500 residents. TIE has provided the observatory with a Tinsley 18" Cassegrain telescope on a 10-year loan. The facility has been built with tremendous support from volunteers and the local school district. We have received an IDEAS grant to provide teacher training workshops which will allow K-12 schools in northern Colorado to make use of the Little Thompson Observatory, including remote observing from classrooms.

  1. Chemistry in the Thermosphere and Ionosphere.

    ERIC Educational Resources Information Center

    Roble, Raymond G.

    1986-01-01

    An informative review which summarizes information about chemical reactions in the thermosphere and ionosphere. Topics include thermal structure, ultraviolet radiation, ionospheric photochemistry, thermospheric photochemistry, chemical heating, thermospheric circulation, auroral processes and ionospheric interactions. Provides suggested followup…

  2. Study of the mid-latitude ionospheric response to geomagnetic storms in the European region

    NASA Astrophysics Data System (ADS)

    Berényi, Kitti Alexandra; Barta, Veronika; Kis, Arpad

    2016-07-01

    Geomagnetic storms affect the ionospheric regions of the terrestrial upper atmosphere through different physical and atmospheric processes. The phenomena that can be regarded as a result of these processes, generally is named as "ionospheric storm". The processes depend on altitude, segment of the day, the geomagnetic latitude and longitude, strength of solar activity and the type of the geomagnetic storm. We examine the data of ground-based radio wave ionosphere sounding measurements of European ionospheric stations (mainly the data of Nagycenk Geophysical Observatory) in order to determine how and to what extent a geomagnetic disturbance of a certain strength affects the mid-latitude ionospheric regions in winter and in summer. For our analysis we used disturbed time periods between November 2012 and June 2015. Our results show significant changing of the ionospheric F2 layer parameters on strongly disturbed days compared to quiet ones. We show that the critical frequencies (foF2) increase compared to their quiet day value when the ionospheric storm was positive. On the other hand, the critical frequencies become lower, when the storm was negative. In our analysis we determined the magnitude of these changes on the chosen days. For a more complete analysis we compare also the evolution of the F2 layer parameters of the European ionosonde stations on a North-South geographic longitude during a full storm duration. The results present the evolution of an ionospheric storm over a geographic meridian. Furthermore, we compared the two type of geomagnetic storms, namely the CME caused geomagnetic storm - the so-called Sudden impulse (Si) storms- and the HSS (High Speed Solar Wind Streams) caused geomagnetic storms -the so-called Gradual storms (Gs)- impact on the ionospheric F2-layer (foF2 parameter). The results show a significant difference between the effect of Si and of the Gs storms on the ionospheric F2-layer.

  3. Modelling ionospheric density structures

    NASA Technical Reports Server (NTRS)

    Schunk, R. W.; Sojka, J. J.

    1989-01-01

    Large-scale density structures are a common feature in the high-latitude ionsphere. The structures were observed in the dayside cusp, polar cap, and nocturnal auroral region over a range of altitudes, including the E-region, F-region and topside ionosphere. The origins, lifetimes and transport characteristics of large-scale density structures were studied with the aid of a three-dimensional, time-dependent ionospheric model. Blob creation due to particle precipitation, the effect that structured electric fields have on the ionosphere, and the lifetimes and transport characteristics of density structures for different seasonal, solar cycle, and interplanetary magnetic field (IMF) conditions were studied. The main conclusions drawn are: (1) the observed precipitation energy fluxes are sufficient for blob creation if the plasma is exposed to the precipitation for 5 to 10 minutes; (2) structured electric fields produce structured electron densities, ion temperatures, and ion composition; (3) the lifetime of an F-region density structure depends on several factors, including the initial location where it was formed, the magnitude of the perturbation, season, solar cycle and IMF; and (4) depending on the IMF, horizontal plasma convection can cause an initial structure to break up into multiple structures of various sizes, remain as a single distorted structure, or become stretched into elongated segments.

  4. Ionospheric disturbance dynamo

    SciTech Connect

    Blanc, M.; Richmond, A.D.

    1980-04-01

    A numerical simulation study of the thermospheric winds produced by auroral heating during magnetic storms, and of their global dynamo effects, establishes the main features of the ionospheric disturbanc dynamo. Driven by auroral heating, a Hadley cell is created with equatorward winds blowing above about 120 km at mid-latitudes. The transport of angular momentum by these winds produces a subrotation of the midlatitude thermosphere, or westward motion with respect to the earth. The westward winds in turn drive equatorward Pedersen currents which accumulate charge toward the equator, resulting in the generation of a poleward electric field, a westward E x B drift, and an eastward current. When realistic local time conductivity variations are simulated, the eastward mid-latitude current is found to close partly via lower latitudes, resulting in an 'anti-Sq' type of current vortex. Both electric field and current at low latitudes thus vary in opposition to their normal quiet-day behavior. This total pattern of distrubance winds, electric fields, and currents is superimposed upon the background quiet-day pattern. When the neutral winds are artificially confined on the nightside, the basic pattern of predominantly westward E x B plasma drifts still prevails on the nightside but no longer extends into the dayside. Considerable observational evidence exists, suggesting that the ionospheric disturbance dynamo has an appreciable influence on storm-time ionospheric electric fields at middle and low latitudes.

  5. Ionospheric variability over Japan

    NASA Astrophysics Data System (ADS)

    Ezquer, R. G.; Mosert, M.; Corbella, R.; Erazu, M.; de La Zerda, L.

    The understanding of ionospheric variability is important for the user of ionospheric models. A satellite designer or operator needs to know not only monthly average conditions but also the expected deviations from these mean values. In order to contribute to the studies on ionospheric variability, in this paper values of critical frequencies of F2, F1 and E regions and M(3000)F2 factor measured at 4 Japanese stations are used. Data correspond to equinoxes, solstices, high and low solar activity. Quartiles and median values are used to specify variability, because they have the advantage of being less affected by large deviations that can occur during magnetic storms. The results are similar for the considered stations and show that the highest variability correspond to foF2. For March high solar activity the variability of fof2 decreases during hours of maximum ionisation. The M3000F2 factor, in general, shown low variability. Akita (39.72° N, 140.13° E) showed the highest variability for the three frequencies. Moreover, it can be seen that quartiles are not equidistant from the median value.

  6. The night when the auroral and equatorial ionospheres converged

    NASA Astrophysics Data System (ADS)

    Martinis, C.; Baumgardner, J.; Mendillo, M.; Wroten, J.; Coster, A.; Paxton, L.

    2015-09-01

    An all-sky imaging system at the McDonald Observatory (30.67°N, 104.02°W, 40° magnetic latitude) showed dramatic ionospheric effects during a moderate geomagnetic storm on 1 June 2013. The auroral zone expanded, leading to the observation of a stable auroral red (SAR) arc. Airglow depletions associated with equatorial spread F (ESF) were also seen for the first time at such high magnetic latitude. Total electron content measurements from a Global Positioning System (GPS) receiver exhibited ionospheric irregularities typically associated with ESF. We explore why this moderate geomagnetic disturbance leads to such dramatic ionospheric perturbations at midlatitudes. A corotating interaction region-like driver and a highly contracted plasmasphere caused the SAR arc to occur at L shell ~ 2.3. For ESF at L ~ 2.1, timing of the storm intensification, alignment of the sunset terminator with the central magnetic meridian, and sudden variations in the westward auroral electrojet all combined to trigger equatorial irregularities that reached altitudes of ~ 7000 km. The SAR arc and ESF signatures at the ionospheric foot points of inner magnetosphere L shells (L ~ 2) represent a dramatic convergence of pole to equator/equator to pole coupling at midlatitudes.

  7. UK Solar System Data Centre: Data Archive for Ionospheric Research

    NASA Astrophysics Data System (ADS)

    Wild, Matthew; James, Sarah; Bogdanova, Yulia; Crothers, Steve

    2014-05-01

    The UK Solar System Data Centre (UKSSDC) has been working to improve access to its extensive holdings of historical ionospheric data. In our archive, ionospheric data from 200 stations worldwide (1930s-present), such as ionograms and scaled ionospheric parameters (e.g., foF2, fmin, h'F2), is held on both digital and physical media. From the 1990s these data sets are available in digital form and can be downloaded from our web-interface. Thanks to a Natural Environment Research Council grant we are in the process of digitising a selection, 2,200 out of ~27,000, of UK ionosonde film data to be made available via the web interface. It is hoped that more funding will be made available to continue this exercise over the next few years. The UKSSDC also provides real-time ionospheric data retrieval from two RAL Space ionosondes, Chilton and Port Stanley, alongside other European observatories. The UKSSDC is part of RAL Space based at Rutherford Appleton Laboratory with the electronic address: http://www.ukssdc.ac.uk. This is a UK national data archive facility with open data access and can be used by scientists around the globe.

  8. Low-latitude Ionospheric Heating during Solar Flares

    NASA Astrophysics Data System (ADS)

    Klenzing, J.; Chamberlin, P. C.; Qian, L.; Haaser, R. A.; Burrell, A. G.; Earle, G. D.; Heelis, R. A.; Simoes, F. A.

    2013-12-01

    The advent of the Solar Dynamics Observatory (SDO) represents a leap forward in our capability to measure rapidly changing transient events on the sun. SDO measurements are paired with the comprehensive low latitude measurements of the ionosphere and thermosphere provided by the Communication/Navigation Outage Forecast System (C/NOFS) satellite and state-of-the-art general circulation models to discuss the coupling between the terrestrial upper atmosphere and solar radiation. Here we discuss ionospheric heating as detected by the Coupled Ion-Neutral Dynamics Investigation (CINDI) instrument suite on the C/NOFS satellite during solar flares. Also discusses is the necessity of decoupling the heating due to increased EUV irradiance and that due to geomagnetic storms, which sometimes occur with flares. Increases in both the ion temperature and ion density in the subsolar topside ionosphere are detected within 77 minutes of the 23 Jan 2012 M-class flare, and the observed results are compared with the Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM) using the Flare Irradiance Spectral Model (FISM) as an input.

  9. The Norwegian Naval Observatories

    NASA Astrophysics Data System (ADS)

    Pettersen, Bjørn Ragnvald

    2007-07-01

    Archival material has revealed milestones and new details in the history of the Norwegian Naval Observatories. We have identified several of the instrument types used at different epochs. Observational results have been extracted from handwritten sources and an extensive literature search. These allow determination of an approximate location of the first naval observatory building (1842) at Fredriksvern. No physical remains exist today. A second observatory was established in 1854 at the new main naval base at Horten. Its location is evident on military maps and photographs. We describe its development until the Naval Observatory buildings, including archives and instruments, were completely demolished during an allied air bomb raid on 23 February 1945. The first director, C.T.H. Geelmuyden, maintained scientific standards at the the Observatory between 1842 and 1870, and collaborated with university astronomers to investigate, develop, and employ time-transfer by telegraphy. Their purpose was accurate longitude determination between observatories in Norway and abroad. The Naval Observatory issued telegraphic time signals twice weekly to a national network of sites, and as such served as the first national time-service in Norway. Later the Naval Observatory focused on the particular needs of the Navy and developed into an internal navigational service.

  10. Zelenchukskaya Radio Astronomical Observatory

    NASA Technical Reports Server (NTRS)

    Smolentsev, Sergey; Dyakov, Andrei

    2013-01-01

    This report summarizes information about Zelenchukskaya Radio Astronomical Observatory activities in 2012. Last year a number of changes took place in the observatory to improve some technical characteristics and to upgrade some units to the required status. The report provides an overview of current geodetic VLBI activities and gives an outlook for the future.

  11. Svetloe Radio Astronomical Observatory

    NASA Technical Reports Server (NTRS)

    Smolentsev, Sergey; Rahimov, Ismail

    2013-01-01

    This report summarizes information about the Svetloe Radio Astronomical Observatory activities in 2012. Last year, a number of changes took place in the observatory to improve some technical characteristics and to upgrade some units to their required status. The report provides an overview of current geodetic VLBI activities and gives an outlook for the future.

  12. Einstein Observatory (HEAO-2)

    NASA Astrophysics Data System (ADS)

    Bond, P.; Murdin, P.

    2002-04-01

    The second in the series of HIGH ENERGY ASTROPHYSICAL OBSERVATORIES was launched by an Atlas-Centaur rocket on 13 November 1978. Soon after its insertion into a 470 km circular orbit inclined at 23.5° to the equator, HEAO-2 was named the Einstein Observatory, in celebration of the centenary of Albert Einstein's birth....

  13. The Space Telescope Observatory

    NASA Technical Reports Server (NTRS)

    Bahcall, J. N.; Odell, C. R.

    1979-01-01

    A convenient guide to the expected characteristics of the Space Telescope Observatory for astronomers and physicists is presented. An attempt is made to provide enough detail so that a professional scientist, observer or theorist, can plan how the observatory may be used to further his observing programs or to test theoretical models.

  14. Strasbourg's "Academy" observatory

    NASA Astrophysics Data System (ADS)

    Heck, André

    2011-08-01

    The observing post located on the roof of Strasbourg's 19th-century "Academy" is generally considered as the second astronomical observatory of the city: a transitional facility between the (unproductive) turret lantern at the top of the Hospital Gate and the German (Wilhelminian) Observatory. The current paper reviews recent findings from archives (blueprints, inventories, correspondence, decrees and other documents) shedding some light on this observatory of which virtually nothing was known to this day. While being, thanks to Chrétien Kramp (1760-1826), an effective attempt to establish an actual observatory equipped with genuine instrumentation, the succession of political regimes in France and the continual bidding for moving the university to other locations, together with the faltering of later scholars, torpedoed any significant scientific usage of the place. A meridian instrument with a Cauchoix objective doublet was however recovered by the German observatory and is still existing.

  15. Nonlinear Interactions within the D-Region Ionosphere

    NASA Astrophysics Data System (ADS)

    Moore, Robert

    2016-07-01

    This paper highlights the best results obtained during D-region modification experiments performed by the University of Florida at the High-frequency Active Auroral Research Program (HAARP) observatory between 2007 and 2014. Over this period, we saw a tremendous improvement in ELF/VLF wave generation efficiency. We identified methods to characterize ambient and modified ionospheric properties and to discern and quantify specific types of interactions. We have demonstrated several important implications of HF cross-modulation effects, including "Doppler Spoofing" on HF radio waves. Throughout this talk, observations are compared with the predictions of an ionospheric HF heating model to provide context and guidance for future D-region modification experiments.

  16. Introducing a disturbance ionosphere index

    NASA Astrophysics Data System (ADS)

    Jakowski, N.; Borries, C.; Wilken, V.

    2012-01-01

    Although ionospheric perturbations such as traveling ionospheric disturbances have a strong impact on Global Navigation Satellite Systems (GNSS) and other space-based radio systems, the description of individual perturbations is difficult. To overcome this problem, it is suggested to use a disturbance ionosphere index (DIX) that describes the perturbation degree of the ionosphere in a less specific form as a proxy. Although such an index does not describe the exact propagation conditions at the measurement site, the estimated index number indicates the probability of a potential impact on radio systems used in communication, navigation, and remote sensing. The definition of such a DIX must take into account the following major requirements: relevance to practical needs, objective measure of ionospheric conditions, easy and reproducible computation, and availability of a reliable database. Since the total electron content has been shown in many publications to act as an outstanding parameter for quantifying the range error and also the strength of ionospheric perturbations, we propose a DIX that is based on GNSS measurements. To illustrate the use of the index, recent storms monitored in 2011 and the Halloween storm are discussed. The proposed index is a robust and objective measure of the ionospheric state, applicable to radio systems which are impacted by a highly variable perturbed ionosphere.

  17. The Little Thompson Observatory

    NASA Astrophysics Data System (ADS)

    Schweitzer, A. E.; VanLew, K.; Melsheimer, T.; Sackett, C.

    1999-12-01

    The Little Thompson Observatory is the second member of the Telescopes in Education (TIE) project. Construction of the dome and the remote control system has been completed, and the telescope is now on-line and operational over the Internet. The observatory is located on the grounds of Berthoud High School in northern Colorado. Local schools and youth organizations have prioritized access to the telescope, and there are monthly opportunities for public viewing. In the future, the telescope will be open after midnight to world-wide use by schools following the model of the first TIE observatory, the 24" telescope on Mt. Wilson. Students remotely connect to the observatory over the Internet, and then receive the images on their local computers. The observatory grew out of grassroots support from the local community surrounding Berthoud, Colorado, a town of 3,500 residents. TIE has provided the observatory with a Tinsley 18" Cassegrain telescope on a 10-year loan. The facility has been built with tremendous support from volunteers and the local school district. With funding from an IDEAS grant, we have begun teacher training workshops which will allow K-12 schools in northern Colorado to make use of the Little Thompson Observatory, including remote observing from classrooms.

  18. The Virtual Observatory: I

    NASA Astrophysics Data System (ADS)

    Hanisch, R. J.

    2014-11-01

    The concept of the Virtual Observatory arose more-or-less simultaneously in the United States and Europe circa 2000. Ten pages of Astronomy and Astrophysics in the New Millennium: Panel Reports (National Academy Press, Washington, 2001), that is, the detailed recommendations of the Panel on Theory, Computation, and Data Exploration of the 2000 Decadal Survey in Astronomy, are dedicated to describing the motivation for, scientific value of, and major components required in implementing the National Virtual Observatory. European initiatives included the Astrophysical Virtual Observatory at the European Southern Observatory, the AstroGrid project in the United Kingdom, and the Euro-VO (sponsored by the European Union). Organizational/conceptual meetings were held in the US at the California Institute of Technology (Virtual Observatories of the Future, June 13-16, 2000) and at ESO Headquarters in Garching, Germany (Mining the Sky, July 31-August 4, 2000; Toward an International Virtual Observatory, June 10-14, 2002). The nascent US, UK, and European VO projects formed the International Virtual Observatory Alliance (IVOA) at the June 2002 meeting in Garching, with yours truly as the first chair. The IVOA has grown to a membership of twenty-one national projects and programs on six continents, and has developed a broad suite of data access protocols and standards that have been widely implemented. Astronomers can now discover, access, and compare data from hundreds of telescopes and facilities, hosted at hundreds of organizations worldwide, stored in thousands of databases, all with a single query.

  19. Effective recombination coefficients in the high-latitude lower ionosphere from solar eclipse observations

    NASA Astrophysics Data System (ADS)

    Cherniakov, Sergey

    2016-07-01

    The photochemistry of processes in the lower ionosphere is rather difficult and up to the end is not developed: it is necessary to specify photochemical schemes, there is big uncertainty in coefficients of separate reactions and concentration of small neutral components. Therefore introduction of the effective coefficients determining the total speed of several reactions was widely adopted when modeling the lower ionosphere, especially the D-region. Experimental opportunities of obtaining of effective recombination coefficients are rather limited. One of the methods allows to define effective recombination coefficients is based on the phenomenon of a solar eclipse and the changes of electron concentration in the ionosphere connected with it. During a solar eclipse there is a short-term and controlled change of solar ionizing radiation intensity that allows to research photochemical processes at known input parameters. The time delay between the eclipse maximum (the sunlight minimum) and the electron concentration minimum at the chosen height during the "short night" is defined as the "sluggishness" [Appleton E.V., 1953] and "relaxation time" [Mitra A., 1974]. The received time delay from observations at the considered ionosphere height with the known electron concentration value gives possibility to calculate the effective recombination coefficient for this height. During solar eclipses on 1 August 2008, on 1 June 2011 and on 20 March 2015 at the partial reflection facility of the observatory "Tumanny" (69° N, 35.7 E) observations of the lower ionosphere behavior were made. On the basis of the obtained data the electron concentration profiles at the heights of the lower ionosphere were received. Calculation of relaxation times allowed to define effective recombination coefficients at some heights of D region of the ionosphere. Appleton, E. V. A note on the "sluggishness" of the ionosphere // J. Atmos. Terr. Phys. - 1953. - Vol. 3, N 5. - P. 282-284. Mitra, A. P

  20. Ionospheric wave spectrum measurements

    NASA Technical Reports Server (NTRS)

    Harker, K. J.; Ilic, D. B.; Crawford, F. W.

    1979-01-01

    The local spectrum S(k, omega) of either potential or electron-density fluctuations can be used to determine macroscopic-plasma characteristics such as the local density and temperature, transport coefficients, and drift current. This local spectrum can be determined by measuring the cross-power spectrum. The paper examines the practicality of using the cross-power spectrum analyzer on the Space Shuttle to measure ionospheric parameters. Particular attention is given to investigating the integration time required to measure the cross-power spectral density to a desired accuracy.

  1. Vertical characteristics of midlatitude E and F region ionospheric drifts during disturbed conditions..

    NASA Astrophysics Data System (ADS)

    Boska, Josef; Kouba, Daniel; Koucka Knizova, Petra; Potuznikova, Katerina

    2015-04-01

    Modern HF digisonde DPS-4 D (Digisonde Portable Sounder), which is in operation at the Pruhonice observatory of the Institute of Atmospheric Physics, Prague (IAP) from 2004, enables us to carry out standard ionospheric sounding and ionospheric drifts measurements. Using standard mode of automatic drift (autodrift mode) measurements the velocity of the F region drifts is usually determined in the vicinity of the peak of the electron density profile (N(h) profile). Since 2005 we are also measuring ionospheric drifts at the heights of the ionospheric E region. This new experimental arrangement makes possible to study vertical changes and profiles of the ionospheric drift velocity in two different ionospheric regions. From E region within the altitudinal interval of 90-150 km to F region in altitudes from 150 km up to height of the maximum electron density profile N(h). This paper present the results of the analysis of the plasma drifts velocity in two different ionospheric regions observed under quiet geomagnetic and ionospheric conditions and especially during ionospheric spread F conditions. These spread F conditions are often observed in the ionosphere as effect of travelling ionopheric disturbances TIDs. The presence of this TIDS can be detected from the F layer isoelectrondensity contours. The spread F conditions are often present also under moderate-to-intense ionospheric and geomagnetic storm conditions. Our results shows, that behavior of Es layer drifts can be different than drifts in E-layer. During winter geomagnetic storm -more dramatic increasing of all drift velocities components was observed (50 - 100 m/s vertical drift component). Different behaviour ionospheric drifts at the heights intervals 90 - 110 km and 110 - 130 km was observed during winter storm. Significant height changes of the drift velocity height profile in the interval of heights 90 - 130 km during winter event was observed. Our results shows that behavior of Es layer drifts can be

  2. Advanced Ionospheric Sensing using GROUP-C and LITES aboard the ISS

    NASA Astrophysics Data System (ADS)

    Budzien, S. A.; Stephan, A. W.; Chakrabarti, S.; Finn, S. C.; Cook, T.; Powell, S. P.; O'Hanlon, B.; Bishop, R. L.

    2015-12-01

    The GPS Radio Occultation and Ultraviolet Photometer Co-located (GROUP-C) and Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) experiments are manifested for flight aboard the International Space Station (ISS) in 2016 as part of the Space Test Program Houston #5 payload. The two experiments provide technical development and risk-reduction for future DoD space weather sensors suitable for ionospheric specification, space situational awareness, and data products for global ionosphere assimilative models. In addition, the combined instrument complement of these two experiments offers a unique opportunity to study structures of the nighttime ionosphere. GROUP-C includes an advanced GPS receiver providing ionospheric electron density profiles and scintillation measurements and a high-sensitivity far-ultraviolet photometer measuring horizontal ionospheric gradients. LITES is an imaging spectrograph that spans 60-140 nm and will obtain high-cadence limb profiles of the ionosphere and thermosphere from 150-350 km altitude. In the nighttime ionosphere, recombination of O+ and electrons produces optically thin emissions at 91.1 and 135.6 nm that can be used to tomographically reconstruct the two-dimensional plasma distribution in the orbital plane below ISS altitudes. Ionospheric irregularities, such as plasma bubbles and blobs, are transient features of the low and middle latitude ionosphere with important implications for operational systems. Irregularity structures have been studied primarily using ground-based systems, though some spaced-based remote and in-situ sensing has been performed. An ionospheric observatory aboard the ISS would provide new capability to study low- and mid-latitude ionospheric structures on a global scale. By combining for the first time high-sensitivity in-track photometry, vertical ionospheric airglow spectrographic imagery, and recent advancements in UV tomography, high-fidelity tomographic reconstruction of

  3. Prototype optical SETI observatory

    NASA Astrophysics Data System (ADS)

    Kingsley, Stuart A.

    1996-06-01

    The Optical Search for Extraterrestrial Intelligence (OSETI) is based on the premise that there are ETIs within our galaxy which are targeting star systems like our own with free-space beams. Upon these beams will ride attention- getting beacon signals and wideband data channels. Perhaps the wideband channels form part of a Galactic Information Superhighway, a Galactic Internet to which we are presently oblivious. The Columbus Optical SETI Observatory described in this paper is intended to be a prototype observatory which might lead to a new renaissance in both optical SETI and optical astronomy. It is hoped that the observatory design will be emulated by both the professional and amateur communities. The modern-day OSETI observatory is one that is more affordable than ever. With the aid of reasonably priced automatic telescopes, low-cost PCs, software and signal processing boards, Optical SETI can become accessible to all nations, professional scientific groups, amateur astronomy societies and even individuals.

  4. Global Health Observatory (GHO)

    MedlinePlus

    ... repository Reports Country statistics Map gallery Standards Global Health Observatory (GHO) data Monitoring health for the SDGs ... relevant web pages on the theme. Monitoring the health goal: indicators of overall progress Mortality and global ...

  5. Observatory Improvements for SOFIA

    NASA Technical Reports Server (NTRS)

    Peralta, Robert A.; Jensen, Stephen C.

    2012-01-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a joint project between NASA and Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), the German Space Agency. SOFIA is based in a Boeing 747 SP and flown in the stratosphere to observe infrared wavelengths unobservable from the ground. In 2007 Dryden Flight Research Center (DFRC) inherited and began work on improving the plane and its telescope. The improvements continue today with upgrading the plane and improving the telescope. The Observatory Verification and Validation (V&V) process is to ensure that the observatory is where the program says it is. The Telescope Status Display (TSD) will provide any information from the on board network to monitors that will display the requested information. In order to assess risks to the program, one must work through the various threats associate with that risk. Once all the risks are closed the program can work towards improving the observatory.

  6. Stratospheric Observatory for Infrared Astronomy (SOFIA) system concept

    NASA Technical Reports Server (NTRS)

    Wiltsee, Christopher B.; Brooks, Walter F.

    1989-01-01

    The system concept for the Stratospheric Observatory for Infrared Astronomy (SOFIA), as developed by NASA Ames Research Center is described. The SOFIA facility is a 3-meter class optical/infrared/submillimeter telescope mounted in an open cavity in the forebody of a Boeing 747 aircraft, to be operational in 1992. It represents the next generation of Ames' existing airborne IR facilities, and is about ten times more sensitive than the Kuiper Airborne Observatory (KAO) with 3 times better angular resolution, and able to detect all the far-infrared point sources discovered by IRAS (Infrared Astronomical Satellite) survey in 1983. Major requirements and design attributes of the SOFIA telescope are presented, along with a brief description of the Ground Support/Operations System.

  7. Hawaiian Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Orr, Tim R.

    2008-01-01

    Lava from Kilauea volcano flowing through a forest in the Royal Gardens subdivision, Hawai'i, in February 2008. The Hawaiian Volcano Observatory (HVO) monitors the volcanoes of Hawai'i and is located within Hawaiian Volcanoes National Park. HVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Kilauea and HVO at http://hvo.wr.usgs.gov.

  8. Ionospheric and magnetospheric plasmapauses'

    NASA Technical Reports Server (NTRS)

    Grebowsky, J. M.; Hoffman, J. H.; Maynard, N. C.

    1977-01-01

    During August 1972, Explorer 45 orbiting near the equatorial plane with an apogee of about 5.2 R sub e traversed magnetic field lines in close proximity to those simultaneously traversed by the topside ionospheric satellite ISIS 2 near dusk in the L range 2-5.4. The locations of the Explorer 45 plasmapause crossings during this month were compared to the latitudinal decreases of the H(+) density observed on ISIS 2 near the same magnetic field lines. The equatorially determined plasmapause field lines typically passed through or poleward of the minimum of the ionospheric light ion trough, with coincident satellite passes occurring for which the L separation between the plasmapause and trough field lines was between 1 and 2. Vertical flows of the H(+) ions in the light ion trough as detected by the magnetic ion mass spectrometer on ISIS were directed upward with velocities between 1 and 2 kilometers/sec near dusk on these passes. These velocities decreased to lower values on the low latitude side of the H(+) trough but did not show any noticeable change across the field lines corresponding to the magnetospheric plasmapause.

  9. Ionospheric effects of the missile destruction on December 9, 2009

    NASA Astrophysics Data System (ADS)

    Kozlovsky, Alexander; Shalimov, Sergey; Lukianova, Renata

    2014-05-01

    We report on ionosonde and meteor radar observations made in Sodankyla Geophysical Observatory (SGO, 67N, 27E, Finland) on December 9, 2009 during a test launch of the Russian solid propellant military missile. Because of the technical problem the missile was self-destroyed around 07 UT at ionospheric height (170-260 km) over the Kola Peninsula (Russia), at a distance about 500 km to east from the observatory. Products of the explosion, including long-lived ionized aluminum oxides, were spread into the large area and reached the region of SGO meteor radar observations in about 2 hours (around 09 UT). After about 3 hours (around 10 UT) a sporadic E layer presumably composed of the remains was observed close to the zenith of the SGO ionosonde. We present the data and discuss possible mechanisms accounting for both vertical and horizontal transport of the remains. Theoretical estimations suggest that the observed transport could be likely due to thermospheric turbulence.

  10. Creating Griffith Observatory

    NASA Astrophysics Data System (ADS)

    Cook, Anthony

    2013-01-01

    Griffith Observatory has been the iconic symbol of the sky for southern California since it began its public mission on May 15, 1935. While the Observatory is widely known as being the gift of Col. Griffith J. Griffith (1850-1919), the story of how Griffith’s gift became reality involves many of the people better known for other contributions that made Los Angeles area an important center of astrophysics in the 20th century. Griffith began drawing up his plans for an observatory and science museum for the people of Los Angeles after looking at Saturn through the newly completed 60-inch reflector on Mt. Wilson. He realized the social impact that viewing the heavens could have if made freely available, and discussing the idea of a public observatory with Mt. Wilson Observatory’s founder, George Ellery Hale, and Director, Walter Adams. This resulted, in 1916, in a will specifying many of the features of Griffith Observatory, and establishing a committee managed trust fund to build it. Astronomy popularizer Mars Baumgardt convinced the committee at the Zeiss Planetarium projector would be appropriate for Griffith’s project after the planetarium was introduced in Germany in 1923. In 1930, the trust committee judged funds to be sufficient to start work on creating Griffith Observatory, and letters from the Committee requesting help in realizing the project were sent to Hale, Adams, Robert Millikan, and other area experts then engaged in creating the 200-inch telescope eventually destined for Palomar Mountain. A Scientific Advisory Committee, headed by Millikan, recommended that Caltech Physicist Edward Kurth be put in charge of building and exhibit design. Kurth, in turn, sought help from artist Russell Porter. The architecture firm of John C. Austin and Fredrick Ashley was selected to design the project, and they adopted the designs of Porter and Kurth. Philip Fox of the Adler Planetarium was enlisted to manage the completion of the Observatory and become its

  11. Improving geomagnetic observatory data in the South Atlantic Anomaly

    NASA Astrophysics Data System (ADS)

    Matzka, Jürgen; Morschhauser, Achim; Brando Soares, Gabriel; Pinheiro, Katia

    2016-04-01

    The Swarm mission clearly proofs the benefit of coordinated geomagnetic measurements from a well-tailored constellation in order to recover as good as possible the contributions of the various geomagnetic field sources. A similar truth applies to geomagnetic observatories. Their scientific value can be maximised by properly arranging the position of individual observatories with respect to the geometry of the external current systems in the ionosphere and magnetosphere, with respect to regions of particular interest for secular variation, and with respect to regions of anomalous electric conductivity in the ground. Here, we report on our plans and recent efforts to upgrade geomagnetic observatories and to recover unpublished data from geomagnetic observatories at low latitudes in the South Atlantic Anomaly. In particular, we target the magnetic equator with the equatorial electrojet and low latitudes to characterise the Sq- and ring current. The observatory network that we present allows also to study the longitudinal structure of these external current systems. The South Atlantic Anomaly region is very interesting due to its secular variation. We will show newly recovered data and comparisons with existing data sets. On the technical side, we introduce low-power data loggers. In addition, we use mobile phone data transfer, which is rapidly evolving in the region and allows timely data access and quality control at remote sites that previously were not connected to the internet.

  12. NASA'S Great Observatories

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Why are space observatories important? The answer concerns twinkling stars in the night sky. To reach telescopes on Earth, light from distant objects has to penetrate Earth's atmosphere. Although the sky may look clear, the gases that make up our atmosphere cause problems for astronomers. These gases absorb the majority of radiation emanating from celestial bodies so that it never reaches the astronomer's telescope. Radiation that does make it to the surface is distorted by pockets of warm and cool air, causing the twinkling effect. In spite of advanced computer enhancement, the images finally seen by astronomers are incomplete. NASA, in conjunction with other countries' space agencies, commercial companies, and the international community, has built observatories such as the Hubble Space Telescope, the Compton Gamma Ray Observatory, and the Chandra X-ray Observatory to find the answers to numerous questions about the universe. With the capabilities the Space Shuttle provides, scientist now have the means for deploying these observatories from the Shuttle's cargo bay directly into orbit.

  13. Ionospheric scintillation studies

    NASA Technical Reports Server (NTRS)

    Rino, C. L.; Freemouw, E. J.

    1973-01-01

    The diffracted field of a monochromatic plane wave was characterized by two complex correlation functions. For a Gaussian complex field, these quantities suffice to completely define the statistics of the field. Thus, one can in principle calculate the statistics of any measurable quantity in terms of the model parameters. The best data fits were achieved for intensity statistics derived under the Gaussian statistics hypothesis. The signal structure that achieved the best fit was nearly invariant with scintillation level and irregularity source (ionosphere or solar wind). It was characterized by the fact that more than 80% of the scattered signal power is in phase quadrature with the undeviated or coherent signal component. Thus, the Gaussian-statistics hypothesis is both convenient and accurate for channel modeling work.

  14. Models of Titan's Ionosphere

    NASA Astrophysics Data System (ADS)

    Robertson, I. P.; Cravens, T. E.; Waite, J. H.; Wahlund, J.; Yelle, R. V.; Vuitton, V.; Coates, A.; Magee, B.; Gell, D. A.

    2007-12-01

    During the TA and T18 encounters with Titan, in situ measurements were made of Titan's atmosphere and ionosphere by several instruments on board the Cassini Orbiter, including the Ion and Neutral Mass Spectrometer (INMS), the Langmuir probe on the Cassini Radio and Plasma Wave Experiment (RPWS), and the Cassini Plasma Spectrometer Subsystem (CAPS). Both of these encounters were on the day as well as the night side of Titan. The model uses neutral densities measured by the INMS instrument and the electron temperature was measured by the RPWS instrument. The model also includes energetic electron fluxes measured by the CAPS instrument, which act as an important source of ionization on the night side. The modeled ion densities are compared with densities measured by INMS in its Open Source mode.

  15. Whistler wave-induced ionospheric plasma turbulence: Source mechanisms and remote sensing

    NASA Astrophysics Data System (ADS)

    Pradipta, R.; Rooker, L. A.; Whitehurst, L. N.; Lee, M. C.; Ross, L. M.; Sulzer, M. P.; Gonzalez, S.; Tepley, C.; Aponte, N.; See, B. Z.; Hu, K. P.

    2013-10-01

    We report a series of experiments conducted at Arecibo Observatory in the past, aimed at the investigation of 40.75 kHz whistler wave interactions with ionospheric plasmas and the inner radiation belts at L=1.35. The whistler waves are launched from a Naval transmitter (code-named NAU) operating in Aguadilla, Puerto Rico at the frequency and power of 40.75 kHz and 100 kW, respectively. Arecibo radar, CADI, and optical instruments were used to monitor the background ionospheric conditions and detect the induced ionospheric plasma effects. Four-wave interaction processes produced by whistler waves in the ionosphere can excite lower hybrid waves, which can accelerate ionospheric electrons. Furthermore, whistler waves propagating into the magnetosphere can trigger precipitation of energetic electrons from the radiation belts. Radar and optical measurements can distinguish wave-wave and wave-particle interaction processes occurring at different altitudes. Electron acceleration by different mechanisms can be verified from the radar measurements of plasma lines. To facilitate the coupling of NAU-launched 40.75 kHz whistler waves into the ionosphere, we can rely on naturally occurring spread F irregularities to serve as ionospheric ducts. We can also use HF wave-created ducts/artificial waveguides, as demonstrated in our earlier Arecibo experiments and recent Gakona experiments at HAARP. The newly constructed Arecibo HF heater will be employed in our future experiments, which can extend the study of whistler wave interactions with the ionosphere and the magnetosphere/radiation belts as well as the whistler wave conjugate propagation between Arecibo and Puerto Madryn, Argentina.

  16. Iranian National Observatory

    NASA Astrophysics Data System (ADS)

    Khosroshahi, H. G.; Danesh, A.; Molaeinezhad, A.

    2016-09-01

    The Iranian National Observatory is under construction at an altitude of 3600m at Gargash summit 300km southern Tehran. The site selection was concluded in 2007 and the site monitoring activities have begun since then, which indicates a high quality of the site with a median seeing of 0.7 arcsec through the year. One of the major observing facilities of the observatory is a 3.4m Alt-Az Ritchey-Chretien optical telescope which is currently under design. This f/11 telescope will be equipped with high resolution medium-wide field imaging cameras as well as medium and high resolution spectrographs. In this review, I will give an overview of astronomy research and education in Iran. Then I will go through the past and present activities of the Iranian National Observatory project including the site quality, telescope specifications and instrument capabilities.

  17. The Collaborative Heliophysics Observatory

    NASA Astrophysics Data System (ADS)

    Hurlburt, N.; Freeland, S.; Cheung, M.; Bose, P.

    2007-12-01

    The Collaborative Heliophysics Observatory (CHO) would provide a robust framework and enabling tools to fully utilize the VOs for scientific discovery and collaboration. Scientists across the realm of heliophysics would be able to create, use and share applications -- either as services using familiar tools or through intuitive workflows -- that orchestrate access to data across all virtual observatories. These applications can be shared freely knowing that proper recognition of data and processing components are acknowledged; that erroneous use of data is flagged; and that results from the analysis runs will in themselves be shared Ð all in a transparent and automatic fashion. In addition, the CHO would incorporate cross-VO models and tools to weave the various virtual observatories into a unified system. These provide starting points for interactions across the solar/heliospheric and heliospheric/magnetospheric boundaries.

  18. SOFIA: The future of airborne astronomy

    NASA Technical Reports Server (NTRS)

    Erickson, Edwin F.; Davidson, Jacqueline A.

    1995-01-01

    For the past 20 years, the 91 cm telescope in NASA's Kuiper Airborne Observatory (KAO) has enabled scientists to observe infrared sources which are obscured by the earth's atmosphere at ground-based sites, and to observe transient astronomical events from anywhere in the world. To augment this capability, the United States and German Space Agencies (NASA and DARA) are collaborating in plans to replace the KAO with a 2.5 meter telescope installed in a Boeing 747 aircraft: SOFIA - The Stratospheric Observatory for Infrared Astronomy. SOFIA's large aperture, wide wavelength coverage, mobility, accessibility, and sophisticated instruments will permit a broad range of scientific studies, some of which are described here. Its unique features complement the capabilities of other future space missions. In addition, SOFIA has important potential as a stimulus for development of new technology and as a national resource for education of K-12 teachers. If started in 1996, SOFIA will be flying in the year 2000.

  19. Ionospheric disturbances during November 30-December 1, 1988. XI - Abnormal propagations of HF and VHF radio waves

    NASA Astrophysics Data System (ADS)

    Ichinose, Masaru; Kamata, Mitsuhiro

    1992-07-01

    Unusual propagations of HF and VHF radio waves associated with a geomagnetic storm during the period from November 30 to December 1, 1988 are investigated using ionospheric data collected from Japan, China, and Taiwan. The increased field strength of the Japanese frequency standard signals (JJY 2.5 MHz and 5 MHz) which were received at Akita Radio Wave Observatory on the night of November 30 seem to have been caused by increased MUFs and/or scattering due to the disturbed ionosphere. The VHF-TV radio waves propagated from China were received at Kokubunji in Tokyo. One of the most probable mechanisms explaining this unusual propagation of VHF is a one-hop-F2 mode of propagation created by an ionosphere with an anomalously high f0F2. It was found out that these unusual HF and VHF propagations were attributed to unusual ionospheric conditions associated with these geomagnetic disturbances.

  20. The worldwide ionospheric data base

    NASA Technical Reports Server (NTRS)

    Bilitza, Dieter

    1989-01-01

    The worldwide ionospheric data base is scattered over the entire globe. Different data sets are held at different institutions in the U.S., U.S.S.R., Australia, Europe, and Asia. The World Data Centers on the different continents archive and distribute part of the huge data base; the scope and cross section of the individual data holdings depend on the regional and special interest of the center. An attempt is made to pull together all the strings that point toward different ionospheric data holdings. Requesters are provided with the information about what is available and where to get it. An attempt is also made to evaluate the reliability and compatibility of the different data sets based on the consensus in the ionospheric research community. The status and accuracy of the standard ionospheric models are also discussed because they may facilitate first order assessment of ionospheric effects. This is a first step toward an ionospheric data directory within the framework of NSSDC's master directory.

  1. Sodankylä ionospheric tomography data set 2003-2014

    NASA Astrophysics Data System (ADS)

    Norberg, Johannes; Roininen, Lassi; Kero, Antti; Raita, Tero; Ulich, Thomas; Markkanen, Markku; Juusola, Liisa; Kauristie, Kirsti

    2016-07-01

    Sodankylä Geophysical Observatory has been operating a receiver network for ionospheric tomography and collecting the produced data since 2003. The collected data set consists of phase difference curves measured from COSMOS navigation satellites from the Russian Parus network (Wood and Perry, 1980) and tomographic electron density reconstructions obtained from these measurements. In this study vertical total electron content (VTEC) values are integrated from the reconstructed electron densities to make a qualitative and quantitative analysis to validate the long-term performance of the tomographic system. During the observation period, 2003-2014, there were three to five operational stations at the Fennoscandia sector. Altogether the analysis consists of around 66 000 overflights, but to ensure the quality of the reconstructions, the examination is limited to cases with descending (north to south) overflights and maximum elevation over 60°. These constraints limit the number of overflights to around 10 000. Based on this data set, one solar cycle of ionospheric VTEC estimates is constructed. The measurements are compared against the International Reference Ionosphere (IRI)-2012 model, F10.7 solar flux index and sunspot number data. Qualitatively the tomographic VTEC estimate corresponds to reference data very well, but the IRI-2012 model results are on average 40 % higher than that of the tomographic results.

  2. Comparison of ionospheric plasma drifts obtained by different techniques

    NASA Astrophysics Data System (ADS)

    Kouba, Daniel; Arikan, Feza; Arikan, Orhan; Toker, Cenk; Mosna, Zbysek; Gok, Gokhan; Rejfek, Lubos; Ari, Gizem

    2016-07-01

    Ionospheric observatory in Pruhonice (Czech Republic, 50N, 14.9E) provides regular ionospheric sounding using Digisonde DPS-4D. The paper is focused on F-region vertical drift data. Vertical component of the drift velocity vector can be estimated by several methods. Digisonde DPS-4D allows sounding in drift mode with direct output represented by drift velocity vector. The Digisonde located in Pruhonice provides direct drift measurement routinely once per 15 minutes. However, also other different techniques can be found in the literature, for example the indirect estimation based on the temporal evolution of measured ionospheric characteristics is often used for calculation of the vertical drift component. The vertical velocity is thus estimated according to the change of characteristics scaled from the classical quarter-hour ionograms. In present paper direct drift measurement is compared with technique based on measuring of the virtual height at fixed frequency from the F-layer trace on ionogram, technique based on variation of h`F and hmF. This comparison shows possibility of using different methods for calculating vertical drift velocity and their relationship to the direct measurement used by Digisonde. This study is supported by the Joint TUBITAK 114E092 and AS CR 14/001 projects.

  3. First results from the Swarm Dedicated Ionospheric Field Inversion chain

    NASA Astrophysics Data System (ADS)

    Chulliat, A.; Vigneron, P.; Hulot, G.

    2016-06-01

    Data-based modeling of the magnetic field originating in the Earth's ionosphere is challenging due to the multiple timescales involved and the small spatial scales of some of the current systems, especially the equatorial electrojet (EEJ) that flows along the magnetic dip equator. The Dedicated Ionospheric Field Inversion (DIFI) algorithm inverts a combination of Swarm satellite and ground observatory data at mid- to low latitudes and provides models of the solar-quiet (Sq) and EEJ magnetic fields on the ground and at satellite altitude. The basis functions of these models are spherical harmonics in quasi-dipole coordinates and Fourier series describing the 24-, 12-, 8- and 6-h periodicities, as well as the annual and semiannual variations. A 1-D conductivity model of the Earth and a 2-D conductivity model of the oceans and continents are used to separate the primary ionospheric field from its induced counterpart. First results from the DIFI algorithm confirm several well-known features of the seasonal variability and westward drift speed of the Sq current systems. They also reveal a peculiar seasonal variability of the Sq field in the Southern hemisphere and a longitudinal variability reminiscent of the EEJ wave-4 structure in the same hemisphere. These observations suggest that the Sq and EEJ currents might be electrically coupled, but only for some seasons and longitudes and more so in the Southern hemisphere than in the Northern hemisphere.

  4. Yellowstone Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Lowenstern, Jacob

    2008-01-01

    Eruption of Yellowstone's Old Faithful Geyser. Yellowstone hosts the world's largest and most diverse collection of natural thermal features, which are the surface expression of magmatic heat at shallow depths in the crust. The Yellowstone system is monitored by the Yellowstone Volcano Observatory (YVO), a partnership among the U.S. Geological Survey (USGS), Yellowstone National Park, and the University of Utah. YVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Yellowstone and YVO at http://volcanoes.usgs.gov/yvo.

  5. Arecibo Observatory for All

    NASA Astrophysics Data System (ADS)

    Isidro, Gloria M.; Pantoja, C. A.; Bartus, P.; La Rosa, C.

    2006-12-01

    We describe new materials available at Arecibo Observatory for visitors with visual impairments. These materials include a guide in Braille that describes the telescope, some basic terms used in radio astronomy and frequently asked questions. We have also designed a tactile model of the telescope. We are interested that blind visitors can participate of the excitement of the visit to the worlds largest radio telescope. We would like to thank the "Fundacion Comunitaria de Puerto Rico" for the scholarship that allowed GMI to work on this project. We would like to express our gratitude to the Arecibo Observatory/NAIC for their support.

  6. WFIRST Observatory Performance

    NASA Technical Reports Server (NTRS)

    Kruk, Jeffrey W.

    2012-01-01

    The WFIRST observatory will be a powerful and flexible wide-field near-infrared facility. The planned surveys will provide data applicable to an enormous variety of astrophysical science. This presentation will provide a description of the observatory and its performance characteristics. This will include a discussion of the point spread function, signal-to-noise budgets for representative observing scenarios and the corresponding limiting sensitivity. Emphasis will be given to providing prospective Guest Observers with information needed to begin thinking about new observing programs.

  7. Cascades Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Driedger, Carolyn; Pallister, John

    2008-01-01

    Washington's Mount St. Helens volcano reawakens explosively on October 1, 2004, after 18 years of quiescence. Scientists at the U.S. Geological Survey's Cascades Volcano Observatory (CVO) study and observe Mount St. Helens and other volcanoes of the Cascade Range in Washington, Oregon, and northern California that hold potential for future eruptions. CVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Mount St. Helens and CVO at http://vulcan.wr.usgs.gov/.

  8. Long Valley Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Hill, David

    2008-01-01

    The ~300-year-old lava on Paoha Island in Mono Lake was produced by the most recent eruption in the Long Valley Caldera area in east-central California. The Long Valley Caldera was formed by a massive volcanic eruption 760,000 years ago. The region is monitored by the Long Valley Observatory (LVO), one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about the Long Valley Caldera region and LVO at http://volcanoes.usgs.gov/lvo.

  9. Recent Advances in Ionospheric Anomalies detection

    NASA Astrophysics Data System (ADS)

    Titov, Anton; Vyacheslav, Khattatov

    2016-07-01

    The variability of the parameters of the ionosphere and ionospheric anomalies are the subject of intensive research. It is widely known and studied in the literature ionospheric disturbances caused by solar activity, the passage of the terminator, artificial heating of high-latitude ionosphere, as well as seismic events. Each of the above types of anomalies is the subject of study and analysis. Analysis of these anomalies will provide an opportunity to improve our understanding of the mechanisms of ionospheric disturbances. To solve this problem are encouraged to develop a method of modeling the ionosphere, based on the assimilation of large amounts of observational data.

  10. Ionospheric effects of the missile destruction on 9 December 2009

    NASA Astrophysics Data System (ADS)

    Kozlovsky, Alexander; Shalimov, Sergey; Lukianova, Renata; Lester, Mark

    2014-05-01

    We report on ionosonde and meteor radar observations made in Sodankylä Geophysical Observatory (SGO, 67°22'N, 26°38'E, Finland) on 9 December 2009, during a test launch of the Russian solid propellant military missile. Due to a technical problem, the missile was self-destroyed around 07 UT at an ionospheric height (near 200 km altitude) over the Kola Peninsula (Russia), at a distance about 500 km to east from the observatory. Products of the explosion were spread into a large area and reached the region of SGO meteor radar observations in about 2 h (around 09 UT). After about 3 h (around 10 UT), a sporadic E layer presumably composed of the remains including long-lived metallic (aluminum and its oxides) ions, was observed near the zenith of the SGO ionosonde. We discuss possible mechanisms accounting for transport of the remains. (1) Since the event occurred during a long-lasting period of extremely low solar and magnetic activity, the ionospheric electric field was unlikely to play a substantial role in the transport of the remains and sporadic E layer formation. (2) The horizontal transport of the remains cannot be explained by the neutral winds based on empirical models. (3) Theoretical estimations suggest that the observed transport could be due to thermospheric turbulence.

  11. Multipoint observations of Ionospheric Alfvén Resonance

    NASA Astrophysics Data System (ADS)

    Baru, N. A.; Koloskov, A. V.; Yampolsky, Y. M.; Rakhmatulin, R. A.

    2016-09-01

    Among the processes that form properties of the geospace in the circumterrestrial plasma the electromagnetic resonances of the Earth, such as Schummann Resonance (SR) and Ionospheric Alfvén Resonance (IAR) are of great importance. IAR is more localized in space than SR and its properties largely depend on the characteristics of the propagation medium. In contrast to the SR, which has global nature and which is continuously observable at any time of the day, IAR signals are registered mostly during the nighttime and demonstrate more variability of the parameters than SR signals. At the Earth surface IAR is registered as Spectral Resonance Structure of the natural electromagnetic noise at frequency range 0.1-40 Hz. In this work we studied an influence of the environment characteristics on IAR parameters by the means of multipoint observations. Annual data series recorded at Ukrainian Antarctic Station "Akademik Vernadsky", Low Frequency Observatory of the Institute of Radio Astronomy near Kharkov (Ukraine) and magnetic station of Sayan Solar Observatory Mondy near Irkutsk (Russia) were used for the analysis. We investigated the behaviour of IAR parameters, such as probability of resonance lines registration and frequency spacing Δ F, for annual and diurnal intervals. These parameters were compared with characteristics of the ionosphere above all of the observation points and geomagnetic activity.

  12. Solar terrestrial observatory

    NASA Technical Reports Server (NTRS)

    1981-01-01

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

  13. Ionospheric current contribution to the main impulse of a negative sudden impulse

    NASA Astrophysics Data System (ADS)

    Vichare, Geeta; Rawat, Rahul; Bhaskar, Ankush; Pathan, Bashir M.

    2014-12-01

    The geomagnetic field response to a moderate-amplitude negative sudden impulse (SI-) that occurred on 14 May 2009 at 10:30 UT was examined at 97 geomagnetic observatories situated all over the globe. The response signature contains a contribution from magnetospheric as well as ionospheric currents. The main impulse (MI) is defined as the maximum depression in the observed geomagnetic field. It is observed that for low-to-high latitudes, the amplitude of the MI is larger in the afternoon to post-dusk sector than in the dawn-noon sector, indicating asymmetry in the MI amplitude. We estimated the contribution at various observatories due to the Chapman-Ferraro magnetopause currents using the Tsyganenko model (T01) and subtracted this from the observed MI amplitude to obtain the contribution due to ionospheric currents. It is found that the ionospheric currents contribute significantly to the MI amplitude of moderate SI- even at low-to-mid latitudes and that the contribution is in the same direction as that from the magnetopause currents near dusk and in the opposite direction near dawn. The equivalent current vectors reveal a clockwise (anticlockwise) ionospheric current loop in the afternoon (morning) sector during the MI of the negative pressure impulse. This evidences an ionospheric twin-cell-vortex current system (DP2) due to field-aligned currents (FACs) associated with the dusk-to-dawn convection electric field during the MI of an SI-. We also estimated the magnetic field variation due to prompt penetration electric fields, which is found to be very small at low latitudes in the present case. The studied SI- is not associated with shock, and hence no preliminary reverse impulse was evident. In addition, the summer hemisphere reveals larger MI amplitudes than the winter hemisphere, indicating once again the role of ionospheric currents.

  14. Airborne gravimetry, altimetry, and GPS navigation errors

    NASA Technical Reports Server (NTRS)

    Colombo, Oscar L.

    1992-01-01

    Proper interpretation of airborne gravimetry and altimetry requires good knowledge of aircraft trajectory. Recent advances in precise navigation with differential GPS have made it possible to measure gravity from the air with accuracies of a few milligals, and to obtain altimeter profiles of terrain or sea surface correct to one decimeter. These developments are opening otherwise inaccessible regions to detailed geophysical mapping. Navigation with GPS presents some problems that grow worse with increasing distance from a fixed receiver: the effect of errors in tropospheric refraction correction, GPS ephemerides, and the coordinates of the fixed receivers. Ionospheric refraction and orbit error complicate ambiguity resolution. Optimal navigation should treat all error sources as unknowns, together with the instantaneous vehicle position. To do so, fast and reliable numerical techniques are needed: efficient and stable Kalman filter-smoother algorithms, together with data compression and, sometimes, the use of simplified dynamics.

  15. Strasbourg's "First" astronomical observatory

    NASA Astrophysics Data System (ADS)

    Heck, André

    2011-08-01

    The turret lantern located at the top of the Strasbourg Hospital Gate is generally considered as the first astronomical observatory of the city, but such a qualification must be treated with caution. The thesis of this paper is that the idea of a tower-observatory was brought back by a local scholar, Julius Reichelt (1637-1717), after he made a trip to Northern Europe around 1666 and saw the "Rundetårn" (Round Tower) recently completed in Copenhagen. There, however, a terrace allowed (and still allows) the full viewing of the sky, and especially of the zenith area where the atmospheric transparency is best. However, there is no such terrace in Strasbourg around the Hospital Gate lantern. Reichelt had also visited Johannes Hevelius who was then developing advanced observational astronomy in Gdansk, but nothing of the kind followed in Strasbourg. Rather, the Hospital Gate observatory was built essentially for the prestige of the city and for the notoriety of the university, and the users of this observing post did not make any significant contributions to the progress of astronomical knowledge. We conclude that the Hospital Gate observatory was only used for rudimentary viewing of bright celestial objects or phenomena relatively low on the horizon.

  16. The IT Observatory.

    ERIC Educational Resources Information Center

    Kent, Kai Iok Tong; Sousa, Antonio C. M.

    1999-01-01

    Describes the IT Observatory, a service of the Macau Productivity and Technology center (CPTTM) that provides information on demand using information technology. The CPTTM is a nonprofit organization funded by the Macau government and private businesses to enhance the productivity of Macau businesses by introducing new technologies and new…

  17. High Energy Astronomy Observatory

    NASA Technical Reports Server (NTRS)

    1980-01-01

    An overview of the High Energy Astronomy Observatory 2 contributions to X-ray astronomy is presented along with a brief description of the satellite and onboard telescope. Observations relating to galaxies and galactic clusters, black holes, supernova remnants, quasars, and cosmology are discussed.

  18. Torun Radio Astronomy Observatory

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Torun Center for Astronomy is located at Piwnice, 15 km north of Torun, Poland. A part of the Faculty of Physics and Astronomy of the Nicolaus Copernicus University, it was created by the union of Torun Radio Astronomy Observatory (TRAO) and the Institute of Astronomy on 1 January 1997....

  19. Arecibo Observatory for All

    ERIC Educational Resources Information Center

    Bartus, P.; Isidro, G. M.; La Rosa, C.; Pantoja, C. A.

    2007-01-01

    We describe new materials available at the Arecibo Observatory for visitors with visual impairments. These materials include a guide in Braille that describes the telescope, explains some basic terms used in radio astronomy, and lists frequently asked questions. We have also designed a tactile model of the telescope. Our interest is in enabling…

  20. The Stratospheric Observatory for Infrared Astronomy (sofia)

    NASA Astrophysics Data System (ADS)

    Gehrz, R. D.; Becklin, E. E.

    2009-06-01

    SOFIA is a 2.5-meter infrared airborne telescope in a Boeing 747-SP that will begin will begin science flights in mid-2009. Flying in the stratosphere at altitudes as high as 45,000 feet, SOFIA will be used to conduct spectroscopic and imaging observations throughout the infrared and sub-mm region with an average transmission of greater than 80 percent. The SOFIA first-generation instrument complement includes broadband imagers, moderate resolution spectrographs capable of resolving broad features due to dust and large molecules, and high resolution spectrometers suitable for kinematic studies of molecular and atomic gas lines at km/s resolution. The characteristics and status of the observatory and its instrumentation will be briefly reviewed. SOFIA`s operations schedule and opportunities for observers and instrument developers will be described.

  1. SOFIA: Stratospheric Observatory for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Erickson, E. F.

    1989-01-01

    SOFIA will be a three meter class telescope operating in a Boeing 747, offering astronomers routine access to infrared wavelengths unavailable from the ground, and with the means to observe transient astronomical events from anywhere in the world. The concept is based on 15 years of experience with NASA's Kuiper Airborne Observatory (KAO), which SOFIA will replace in the mid 1990's. SOFIA's wavelength range covers nearly four decades of the electromagnetic spectrum: from the visible, throughout the infrared and submillimeter, to the microwave region. Relative to the KAO, SOFIA will be roughly ten times more sensitive for compact sources, enabling observations of fainter objects and measurements at higher spectral resolution. Also, it will have three times the angular resolving power for wavelengths greater than 30 microns, permitting more detailed imaging at far infrared wavelengths.

  2. Observing rapid quasi-wave ionospheric disturbance using amplitude charts

    NASA Astrophysics Data System (ADS)

    Kurkin, Vladimir; Laryunin, Oleg; Podlesnyi, Alexey

    Data from vertical (quasi-vertical) sounding are traditionally used for determining a number of ionospheric parameters such as critical frequencies of E and F layers, peaks of these layers, and for reconstructing electron density profiles. In this respect, radio sounding is not used to its full capacity. Modern ionosondes provide additional information encoded in ionospheric echoes, including information on reflected-signal amplitude. The time dependence of the amplitude-frequency characteristic of reflected signal has been named "amplitude chart" (A-chart). Ionosondes used by the ISTP SB RAS Geophysical Observatory for constructing A-charts employ the frequency-modulated continuous-wave (FMCW) signal in a range 1.3-15 MHz. One-minute sounding interval allows a more detailed study of dynamic processes in the ionosphere. The ionosonde has a direct digital synthesizer and direct sampling receiver without automatic gain control (AGC). The absence of AGC and the high dynamic range enable determination of the relative field strength at a receiving point and registration of relative long-term variations in reflected-signal amplitude over the entire range of operating frequencies of the ionosonde. We have revealed that the passage of travelling ionospheric disturbances (TID) along with height-frequency distortion modulates amplitude characteristics of signal. The characteristic depth of the modulation reaches 40 dB. The pronounced alternate vertical stripes typical for A-charts are likely to be associated with focusing properties of TID. In order to examine the space-time structure of TID able to induce such a focusing of the radio waves, we performed ray tracing simulations. We used geometrical-optics approximation, took magneto-ionic effects into account and prescribed electron density to be a stratified electron density profile on which an undulating disturbance was superimposed. This work was supported by the RFBR grant №14-05-00259-а.

  3. The 20 March 2015 total solar eclipse: effects in the high-latitude lower ionosphere

    NASA Astrophysics Data System (ADS)

    Cherniakov, Sergey; Tereshchenko, Valentina; Ogloblina, Olga; Vasiliev, Evgeny; Gomonov, Alexander

    2016-07-01

    The medium-wave facility of partial reflections of the Polar Geophysical Institute (observatory "Tumanny", 69 N, 35.7 E) has observed behavior of the lower high-latitude ionosphere during the 20 March 2015 total solar eclipse. There were several effects during the eclipse. Generally on the heights of the lower ionosphere the "short night" effect had shown, but at some heights local enhanced electron concentration were revealed and the behavior of the electron concentration had the wave-like form. It had seen also at the behavior of the total electron content of the lower ionosphere. The periods and behavior of the wave are considered. It can be explained by influence of acoustic-gravity waves which originated after cooling of the atmosphere by the lunar shadow during its supersonic movement along the earth surface. The periods and behavior of waves during the eclipse were also received using riometer data at the observatory "Tumanny" and the magnetometer at the observatory "Loparskaya" (68.63 N, 33.38 E).

  4. Earthquake-Ionosphere Coupling Processes

    NASA Astrophysics Data System (ADS)

    Kamogawa, Masashi

    After a giant earthquake (EQ), acoustic and gravity waves are excited by the displacement of land and sea surface, propagate through atmosphere, and then reach thermosphere, which causes ionospheric disturbances. This phenomenon was detected first by ionosonde and by HF Doppler sounderin the 1964 M9.2 Great Alaskan EQ. Developing Global Positioning System (GPS), seismogenic ionospheric disturbance detected by total electron content (TEC) measurement has been reported. A value of TEC is estimated by the phase difference between two different carrier frequencies through the propagation in the dispersive ionospheric plasma. The variation of TEC is mostly similar to that of F-region plasma. Acoustic-gravity waves triggered by an earthquake [Heki and Ping, EPSL, 2005; Liu et al., JGR, 2010] and a tsunami [Artu et al., GJI, 2005; Liu et al., JGR, 2006; Rolland, GRL, 2010] disturb the ionosphere and travel in the ionosphere. Besides the traveling ionospheric disturbances, ionospheric disturbances excited by Rayleigh waves [Ducic et al, GRL, 2003; Liu et al., GRL, 2006] as well as post-seismic 4-minute monoperiodic atmospheric resonances [Choosakul et al., JGR, 2009] have been observed after the large earthquakes. Since GPS Earth Observation Network System (GEONET) with more than 1200 GPS receiving points in Japan is a dense GPS network, seismogenic ionospheric disturbance is spatially observed. In particular, the seismogenic ionospheric disturbance caused by the M9.0 off the Pacific coast of Tohoku EQ (henceforth the Tohoku EQ) on 11 March 2011 was clearly observed. Approximately 9 minutes after the mainshock, acoustic waves which propagated radially emitted from the tsunami source area were observed through the TEC measurement (e. g., Liu et al. [JGR, 2011]). Moreover, there was a depression of TEC lasting for several tens of minutes after a huge earthquake, which was a large-scale phenomenon extending to a radius of a few hundred kilometers. This TEC depression may be

  5. Ionospheric observations in southern Norway

    NASA Astrophysics Data System (ADS)

    Kjørsvik, N.; Øvstedal, O.; Pettersen, B. R.; Svendsen, J. G. G.

    2003-04-01

    A permanent GPS reference receiver is established in station AK06 at the campus of NLH, Norway. The monumentation, hardware, software and network connection is according to IGS practice. In this poster the first application of dual frequency GPS observations from this station is presented. Carrier phase and pseudorange observations at 1 Hz are used to monitor ionospheric TEC values. The processing is carried out in near real time. Observation files containing one hour of observations are added to moving observation files containing 24 hours of data. Differential Code Biases (DCB) in the satellites are taken from the IONEX (IONosphere Exchange format) computed by the ionosphere working group of the International GPS Services. The IGS estimate daily Global Ionospheric Models with DCBs and ionospheric Total Electron Content (TEC) parameters. Daily estimates for the receiver DCB are estimated using dual frequency pseudorange observations and satellite DCBs and TEC values from IGS. Final TEC values are estimated using undifferenced carrier phase observations leveled to pseudorange. Hourly snap shots as well as animations are presented on a web-page. GPS-observations from other stations will be added in order to extend the area of coverage.

  6. The International Reference Ionosphere - Climatological Standard for the Ionosphere

    NASA Technical Reports Server (NTRS)

    Bilitza, Dieter

    2006-01-01

    The International Reference Ionosphere (IRI) a joint project of URSI and COSPAR is the defacto standard for a climatological specification of ionospheric parameters. IRI is based on a wide range of ground and space data and has been steadily improved since its inception in 1969 with the ever-increasing volume of ionospheric data and with better mathematical descriptions of the observed global and temporal variation patterns. The IRI model has been validated with a large amount of data including data from the most recent ionospheric satellites (KOMPSAT, ROCSAT and TIMED) and data from global network of ionosondes. Several IRI teams are working on specific aspects of the IRI modeling effort including an improved representation of the topside ionosphere with a seamless transition to the plasmasphere, a new effort to represent the global variation of F2 peak parameters using the Neural Network (NN) technique, and the inclusion of several additional parameters in IRI, e.g., spread-F probability and ionospheric variability. Annual IRI workshops are the forum for discussions of these efforts and for all science activities related to IRI as well as applications of the IRI model in engineering and education. In this paper I will present a status report about the IRI effort with special emphasis on the presentations and results from the most recent IRI Workshops (Paris, 2004; Tortosa, 2005) and on the most important ongoing IRI activities. I will discuss the latest version of the IRI model, IRI-2006, highlighting the most recent changes and additions. Finally, the talk will review some of the applications of the IRI model with special emphasis on the use for radiowave propagation studies and communication purposes.

  7. Arecibo Observatory support of the US international cometary Explorer mission encounter at comet Giacobini-Zinner

    NASA Technical Reports Server (NTRS)

    Gordon, D. D.; Ward, M. T.

    1986-01-01

    The Arecibo Observatory in Puerto Rico participated in the support of the U.S. International Cometary Explorer (ICE) mission when the ICE spacecraft passed through the tail of comet Giacobini-Zinner on September 11, 1985. The Arecibo Observatory is a research facility of the National Astronomy and Ionosphere Center (NAIC) operated by Cornell University under contract to the National Science Foundation (NSF). Coverage of the encounter involved the use of the observatory's 305-m (1000-ft) radio reflector antenna and RF and data system equipment fabricated or modified specifically for support of the ICE mission. The successful implementation, testing, and operation of this temporary receive, record, and data relay capability resulted from a cooperative effort by personnel at the Arecibo Observatory, the Goddard Space Flight Center, and the Jet Propulsion Laboratory.

  8. High Energy Astronomy Observatory program

    NASA Technical Reports Server (NTRS)

    Wojtalik, F. S.

    1979-01-01

    The series of three orbiting high energy astronomy observatories that comprise the HEAO program are described. Several unique designs as well as the attitude control and determination system, used for observatory scan rotation of the first and third missions and for precision pointing on the second mission, are analyzed. Attention is given to observatory requirements, design characteristics, and the RGA performance summary.

  9. NASA's Great Observatories: Paper Model.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC.

    This educational brief discusses observatory stations built by the National Aeronautics and Space Administration (NASA) for looking at the universe. This activity for grades 5-12 has students build paper models of the observatories and study their history, features, and functions. Templates for the observatories are included. (MVL)

  10. Low-latitude ionospheric effects on SBAS

    NASA Astrophysics Data System (ADS)

    Arenas, J.; Sardón, E.; Sainz, A.; Ochoa, B.; Magdaleno, S.

    2016-06-01

    Satellite-based augmentation systems (SBAS) provide augmentation to Global Navigation Satellite Systems (GNSS) users in three areas: (1) broadcasting accurate corrections to GNSS satellite ephemeris, (2) providing a real-time empirical ionospheric model in the service area, and (3) providing integrity information in the form of estimates of the confidence of the ephemeris corrections and ionospheric delays. Ionospheric effects on SBAS are twofold: (a) the input data used by the SBAS will be affected by ionospheric effects, and (b) the more perturbed the ionosphere is, the more difficult it will be to provide accurate and reliable ionospheric information to the users. The ionosphere at low latitudes presents larger variability and more intense phenomena than at midlatitudes. Therefore, SBAS providing service to low-latitude regions will be more affected than those at other latitudes. From the different low-latitude ionospheric effects, this paper will focus on those having the largest impact on SBAS, which are total electron content temporal and spatial gradients, ionospheric scintillations, and depletions. This paper will present the impact of these effects on EGNOS (European Global Navigation Overlay System), the European SBAS. Although EGNOS can be considered as a midlatitude SBAS, it has to provide coverage down to rather low latitudes, so sometimes low-latitude ionospheric effects are observed in the EGNOS data. It will be shown how EGNOS performs under nominal conditions and how its performance is degraded when low-latitude ionospheric phenomena occur. Real EGNOS data affected by low-latitude ionospheric phenomena will be used.

  11. ESO's Two Observatories Merge

    NASA Astrophysics Data System (ADS)

    2005-02-01

    On February 1, 2005, the European Southern Observatory (ESO) has merged its two observatories, La Silla and Paranal, into one. This move will help Europe's prime organisation for astronomy to better manage its many and diverse projects by deploying available resources more efficiently where and when they are needed. The merged observatory will be known as the La Silla Paranal Observatory. Catherine Cesarsky, ESO's Director General, comments the new development: "The merging, which was planned during the past year with the deep involvement of all the staff, has created unified maintenance and engineering (including software, mechanics, electronics and optics) departments across the two sites, further increasing the already very high efficiency of our telescopes. It is my great pleasure to commend the excellent work of Jorge Melnick, former director of the La Silla Observatory, and of Roberto Gilmozzi, the director of Paranal." ESO's headquarters are located in Garching, in the vicinity of Munich (Bavaria, Germany), and this intergovernmental organisation has established itself as a world-leader in astronomy. Created in 1962, ESO is now supported by eleven member states (Belgium, Denmark, Finland, France, Germany, Italy, The Netherlands, Portugal, Sweden, Switzerland, and the United Kingdom). It operates major telescopes on two remote sites, all located in Chile: La Silla, about 600 km north of Santiago and at an altitude of 2400m; Paranal, a 2600m high mountain in the Atacama Desert 120 km south of the coastal city of Antofagasta. Most recently, ESO has started the construction of an observatory at Chajnantor, a 5000m high site, also in the Atacama Desert. La Silla, north of the town of La Serena, has been the bastion of the organization's facilities since 1964. It is the site of two of the most productive 4-m class telescopes in the world, the New Technology Telescope (NTT) - the first major telescope equipped with active optics - and the 3.6-m, which hosts HARPS

  12. Solar Flare and IMF Sector Structure Effects in the Lower Ionosphere

    NASA Technical Reports Server (NTRS)

    Lastovicka, J.

    1984-01-01

    About 1% of all sudden ionospheric disturbances (SIDs) observed at the Panska Ves Observatory (Czechoslovakia), were found to be not of solar-XUV origin. Among them, the very rare SWF events (observed at L = 2.4) of corpuscular origin are the most interesting. The IMF sector structure effects in the midlatitude lower ionosphere are minor in comparison with effects of solar flares, geomagnetic storms, etc. There are two basic types of effects. The first type is a disturbance, best developed in geomagnetic activity, and observed in the night-time ionosphere. It can be interpreted as a response to sector structure related changes of geomagnetic (= magnetospheric) activity. The other type is best developed in the tropospheric vorticity area index and is also observed in the day-time ionosphere in winter. This effect is quietening in the ionosphere as well as troposphere. While the occurrence of the former type is persistent in time, the latter is severely diminished in some periods. All the stratosphere, the 10-mb level temperature and height above Berlin-Tempelhof do not display any observable IMF section structure effect.

  13. Application of the coded long-pulse technique to plasma line studies of the ionosphere

    NASA Technical Reports Server (NTRS)

    Djuth, Frank T.; Sulzer, Michael P.; Elder, John H.

    1994-01-01

    Recently, the coded long-pulse radar technique was tested at Arecibo Observatory, Puerto Rico using photoelectron-enhanced plasma lines in the daytime ionosphere. The technique immediately proved to be a powerful diagnostic tool for studying natural ionospheric phenomena. Our initial observations indicate that extremely accurate measurements of absolute electron density (0.01 to 0.03% error bars) can be achieved with an altitude resolution of 150 m and a temporal resolution of approx. 2 s. In addition, the technique provides information about electron density structure within a 150-m altitude cell and yields parameters from which the energy spectrum of suprathermal electrons (equal to or greater than 5 eV) can be deduced. Our earliest measurements are used to illustrate applications of the coded long-pulse technique to several aeronomic/ionsospheric areas of current interest. These include studies of neutral wave motions in the lower thermosphere, measurements of ion composition in the F(sub 1) region/upper ionosphere, and investigations of electron-gas thermal balance and photoelectron energy loss processes. The technique can be utilized to examine irregularity formation in the F region, probe electron acceleration processes in ionospheric modification experiments, verify the magnetic field dependence of Langmuir wave damping, and more generally test higher order corrections suggested for the Langmuir dispersion relation. It is anticipated that the latter tests will facilitate measurements of ionospheric currents.

  14. Solar flare and IMF sector structure effects in the lower ionosphere

    SciTech Connect

    Lastovicka, J.

    1984-05-01

    About 1% of all sudden ionospheric disturbances (SIDs) observed at the Panska Ves Observatory (Czechoslovakia), were found to be not of solar-XUV origin. Among them, the very rare SWF events (observed at L 2.4) of corpuscular origin are the most interesting. The IMF sector structure effects in the midlatitude lower ionosphere are minor in comparison with effects of solar flares, geomagnetic storms, etc. There are two basic types of effects. The first type is a disturbance, best developed in geomagnetic activity, and observed in the night-time ionosphere. It can be interpreted as a response to sector structure related changes of geomagnetic (magnetospheric) activity. The other type is best developed in the tropospheric vorticity area index and is also observed in the day-time ionosphere in winter. This effect is quietening in the ionosphere as well as troposphere. While the occurrence of the former type is persistent in time, the latter is severely diminished in some periods. All the stratosphere, the 10-mb level temperature and height above Berlin-Tempelhof do not display any observable IMF section structure effect.

  15. High time resolution observations of HF cross-modulation within the D region ionosphere

    NASA Astrophysics Data System (ADS)

    Langston, J.; Moore, R. C.

    2013-05-01

    High-frequency cross-modulation is employed to probe the D region ionosphere during HF heating experiments at the High-frequency Active Auroral Research Program (HAARP) observatory. We have adapted Fejer's well-known cross-modulation probing method to determine the extent of ionospheric conductivity modification in the D region ionosphere with high (5 μsec) time resolution. We demonstrate that the method can be used to analyze D region conductivity changes produced by HF heating both during the initial stages of heating and under steady state conditions. The sequence of CW probe pulses used allow the separation of cross-modulation effects that occur as the probe pulse propagates upward and downward through the heated region. We discuss how this probing technique can be applied to benefit ELF/VLF wave generation experiments and ionospheric irregularities experiments at higher altitudes. We demonstrate that large phase changes equivalent to Doppler shift velocities >60 km/s can be imposed on HF waves propagating through the heated D region ionosphere.

  16. Alaska Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Murray, Tom; Read, Cyrus

    2008-01-01

    Steam plume from the 2006 eruption of Augustine volcano in Cook Inlet, Alaska. Explosive ash-producing eruptions from Alaska's 40+ historically active volcanoes pose hazards to aviation, including commercial aircraft flying the busy North Pacific routes between North America and Asia. The Alaska Volcano Observatory (AVO) monitors these volcanoes to provide forecasts of eruptive activity. AVO is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Augustine volcano and AVO at http://www.avo.alaska.edu.

  17. Did Tsunami-Launched Gravity Waves Trigger Ionospheric Turbulence over Arecibo?

    NASA Astrophysics Data System (ADS)

    Lee, M. C.; Pradipta, R.; Burke, W. J.; Labno, A.; Burton, L. M.; Cohen, J. A.; Dorfman, S. E.; Coster, A. J.; Sulzer, M. P.; Kuo, S. P.

    2008-01-01

    We report on measurements of ionospheric plasma dynamics conducted at the Arecibo Observatory between 20:00 and 24:00 local time (LT) on December 25 and 26, 2004 using the 430 MHz incoherent scatter radar (ISR). For interpretive purposes these measurements are supported by data from two nearby ionosondes and Global Positioning System (GPS) satellites. The ISR detected different ionospheric behaviors during the vertical-transmission periods on the consecutive, magnetically quiet nights. On the night of December 25 the ionosphere descended smoothly and spread F signatures faded. For about two hours on the following evening the bottomside ionosphere rose by ˜50 km, inducing plasma irregularities and intense spread F. Alternating cycles of bottom-side plasma rising and falling persisted through the remainder of the experiments. We postulate that this sinusoidal behavior is a response to gravity waves propagating above Puerto Rico. Nearly simultaneous data from two nearby stations show that GPS signals were modified by variations in total electron content (TEC) indicating the presence of traveling ionospheric disturbances (TIDs). The December 26 experiments were conducted about a day after an MW = 9.2 earthquake launched tsunami waves first across the Indian, then into the Atlantic and Pacific Oceans. We suggest that coupling at the tsunami sea-air interface launched gravity waves that propagated for great distances beneath the mesopause. GPS data recorded TEC variation in Asia, Europe, and the Caribbean, suggesting that TIDs were induced on a global scale at the wake of tsunami-launched gravity waves. Energy from imperfectly ducted gravity waves leaked into the ionosphere, partially over Puerto Rico. The wind-velocity field of these gravity waves caused local ionospheric plasma to rise, seeding bottomside irregularities via the generalized Rayleigh-Taylor instability.

  18. Mount Wilson Observatory

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Mount Wilson Observatory, located in the San Gabriel Mountains near Pasadena, California, was founded in 1904 by George Ellery Hale with financial support from Andrew Carnegie. In the 1920s and 1930s, working at the 2.5 m Hooker telescope, Edwin Hubble made two of the most important discoveries in the history of astronomy: first, that `nebulae' are actually island universes—galaxies—each with bil...

  19. Jodrell Bank Observatory

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The Jodrell Bank Observatory is part of the University of Manchester and was founded by Bernard Lovell in December 1945. Its prime instrument, the 76 m, MK1 radio-telescope, was completed in 1957. It was given a major upgrade in 1971 and is now known as the Lovell Telescope. In its early years it pioneered the technique of long baseline interferometry which led to the discovery of quasars. A majo...

  20. Arecibo Observatory for All

    NASA Astrophysics Data System (ADS)

    Bartus, P.; Isidro, G. M.; La Rosa, C.; Pantoja, C. A.

    We describe new materials available at the Arecibo Observatory for visitors with visual impairments. These materials include a guide in Braille that describes the telescope, explains some basic terms used in radio astronomy, and lists frequently asked questions. We have also designed a tactile model of the telescope. Our interest is in enabling blind visitors to participate in the excitement of visiting the world's largest radio telescope.

  1. The Stratospheric Observatory for Infrared Astronomy (sofia)

    NASA Astrophysics Data System (ADS)

    Gehrz, R. D.; Becklin, E. E.

    2012-06-01

    The joint U.S. and German Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5- meter infrared airborne telescope in a Boeing 747-SP. SOFIA can conduct photometric, spectroscopic, and imaging observations at wavelengths from 0.3 microns to 1.6 millimeters. At SOFIA's maximum service ceiling of 45,000 feet, the average transmission at these wavelengths is greater than 80 percent. SOFIA flys out of the NASA Dryden Flight Research Center aircraft operations facility at Palmdale, CA and the SOFIA Science Mission Operations (SMO) Center is located at NASA Ames Research Center, Moffett Field, CA. SOFIA's first-generation instrument complement includes broadband imagers and spectrographs that can resolve spectral features due to dust and large molecules, and high resolution spectrometers facilitating kinematic studies of molecular and atomic gas lines at km/s resolution. More than 30 science flights of 10 hours length (take-off to landing) were conducted in the past year. About 100 eight to ten hour flights per year are planned by 2014, and the observatory will operate until the mid-2030's.

  2. Metrology and ionospheric observation standards

    NASA Astrophysics Data System (ADS)

    Panshin, Evgeniy; Minligareev, Vladimir; Pronin, Anton

    Accuracy and ionospheric observation validity are urgent trends nowadays. WMO, URSI and national metrological and standardisation services bring forward requirements and descriptions of the ionospheric observation means. Researches in the sphere of metrological and standardisation observation moved to the next level in the Russian Federation. Fedorov Institute of Applied Geophysics (IAG) is in charge of ionospheric observation in the Russian Federation and the National Technical Committee, TC-101 , which was set up on the base of IAG- of the standardisation in the sphere. TC-101 can be the platform for initiation of the core international committee in the network of ISO The new type of the ionosounde “Parus-A” is engineered, which is up to the national requirements. “Parus-A” calibration and test were conducted by National metrological Institute (NMI) -D.I. Mendeleyev Institute for Metrology (VNIIM), signed CIMP MRA in 1991. VNIIM is a basic NMI in the sphere of Space weather (including ionospheric observations), the founder of which was celebrated chemist and metrologist Dmitriy I. Mendeleyev. Tests and calibration were carried out for the 1st time throughout 50-year-history of ionosonde exploitation in Russia. The following metrological characteristics were tested: -measurement range of radiofrequency time delay 0.5-10 ms; -time measurement inaccuracy of radio- frequency pulse ±12mcs; -frequency range of radio impulse 1-20 MHz ; -measurement inaccuracy of radio impulse carrier frequency± 5KHz. For example, the sound impulse simulator that was built-in in the ionosounde was used for measurement range of radiofrequency time delay testing. The number of standards on different levels is developed. - “Ionospheric observation guidance”; - “The Earth ionosphere. Terms and definitions”.

  3. The Russian Virtual Observatory

    NASA Astrophysics Data System (ADS)

    Dluzhnevskaya, O. B.; Malkov, O. Yu.; Kilpio, A. A.; Kilpio, E. Yu.; Kovaleva, D. A.; Sat, L. A.

    The Russian Virtual Observatory (RVO) will be an integral component of the International Virtual Observatory (IVO). The RVO has the main goal of integrating resources of astronomical data accumulated in Russian observatories and institutions (databases, archives, digitized glass libraries, bibliographic data, a remote access system to information and technical resources of telescopes etc.), and providing transparent access for scientific and educational purposes to the distributed information and data services that comprise its content. Another goal of the RVO is to provide Russian astronomers with on-line access to the rich volumes of data and metadata that have been, and will continue to be, produced by astronomical survey projects. Centre for Astronomical Data (CAD), among other Russian institutions, has had the greatest experience in collecting and distributing astronomical data for more than 20 years. Some hundreds of catalogs and journal tables are currently available from the CAD repository. More recently, mirrors of main astronomical data resources (VizieR, ADS, etc) are now maintained in CAD. Besides, CAD accumulates and makes available for the astronomical community information on principal Russian astronomical resources.

  4. Megalithic observatory Kokino

    NASA Astrophysics Data System (ADS)

    Cenev, Gj.

    2006-05-01

    In 2001, on the footpath of a mountain peak, near the village of Kokino, archeologist Jovica Stankovski discovered an archeological site from The Bronze Age. The site occupies a large area and is scaled in two levels. Several stone seats (thrones) are dominant in this site and they are pointing towards the east horizon. The high concentration of the movable archeological material found on the upper platform probably indicates its use in a function containing still unknown cult activities. Due to precise measurements and a detailed archaeoastronomical analysis of the site performed in the past three years by Gjore Cenev, physicist from the Planetarium in Skopje, it was shown that the site has characteristics of a sacred site, but also of a Megalithic Observatory. The markers found in this observatory point on the summer and winter solstices and spring and autumn equinoxes. It can be seen that on both sides of the solstice markers, that there are markers for establishing Moon's positions. The markers are crafted in such a way that for example on days when special rites were performed (harvest rites for example) the Sun filled a narrow space of the marker and special ray lighted the man sitting on only one of the thrones, which of course had a special meaning. According to the positions of the markers that are used for Sun marking, especially on the solstice days, it was calculated that this observatory dates from 1800 B.C.

  5. SOFIA'S Challenge: Scheduling Airborne Astronomy Observations

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy

    2005-01-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) is NASA's next generation airborne astronomical observatory, and will commence operations in 2005. The facility consists of a 747-SP modified to accommodate a 2.5 meter telescope. SOFIA is expected to fly an average of 140 science flights per year over its 20 year lifetime. Depending on the nature of the instrument used during flight, 5-15 observations per flight are expected. The SOFIA telescope is mounted aft of the wings on the port side of the aircraft and is articulated through a range of 20deg to 60deg of elevation. The telescope has minimal lateral flexibility; thus, the aircraft must turn constantly to maintain the telescope's focus on an object during observations. A significant problem in future SOFIA operations is that of scheduling flights in support of observations. Investigators are expected to propose small numbers of observations, and many observations must be grouped together to make up single flights. Flight planning for the previous generation airborne observatory, the Kuiper Airborne Observatory (KAO), was done by hand; planners had to choose takeoff time, observations to perform, and decide on setup-actions (called "dead-legs") to position the aircraft prior to observing. This task frequently required between 6-8 hours to plan one flight The scope of the flight planning problem for supporting GI observations with the anticipated flight rate for SOFIA makes the manual approach for flight planning daunting. In response, we have designed an Automated Flight Planner (AFP) that accepts as input a set of requested observations, designated flight days, weather predictions and fuel limitations, and searches automatically for high-quality flight plans that satisfy all relevant aircraft and astronomer specified constraints. The AFP can generate one candidate flight plan in 5-10 minutes, of computation time, a feat beyond the capabilities of human flight planners. The rate at which the AFP can

  6. Radar soundings of the ionosphere of Mars.

    PubMed

    Gurnett, D A; Kirchner, D L; Huff, R L; Morgan, D D; Persoon, A M; Averkamp, T F; Duru, F; Nielsen, E; Safaeinili, A; Plaut, J J; Picardi, G

    2005-12-23

    We report the first radar soundings of the ionosphere of Mars with the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument on board the orbiting Mars Express spacecraft. Several types of ionospheric echoes are observed, ranging from vertical echoes caused by specular reflection from the horizontally stratified ionosphere to a wide variety of oblique and diffuse echoes. The oblique echoes are believed to arise mainly from ionospheric structures associated with the complex crustal magnetic fields of Mars. Echoes at the electron plasma frequency and the cyclotron period also provide measurements of the local electron density and magnetic field strength.

  7. The Stratospheric Observatory for Infrared Astronomy (SOFIA)

    NASA Astrophysics Data System (ADS)

    Wolf, J.

    2004-05-01

    The Stratospheric Observatory for Infrared Astronomy, SOFIA, will carry a 3-meter-class telescope onboard a Boeing 747SP aircraft to altitudes of 41,000 to 45,000 ft, above most of the atmosphere's IR-absorbing water vapor. The telescope was developed and built in Germany and has been delivered to the U.S. in September 2002. The integration into the B747SP has been com- pleted and functional tests are under way in Waco, Texas. In early 2005 flight-testing of the observatory will initially be dedi-cated to the re-certification of the modified aircraft, then performance tests of the telescope and the electronics and data systems will commence. Later in 2005 after transferring to its home base, NASA's Ames Research Center in Moffett Field, California, SOFIA will start astrophysical observations. A suite of specialized infrared cameras and spectrometers covering wave-lengths between 1 and 600 ?m is being developed by U.S. and German science institutions. In addition to the infrared instruments, a high-speed visible range CCD camera will use the airborne observatory to chase the shadows of celestial bodies during occultations. Once SOFIA will be in routine operations with a planned observing schedule of up to 960 hours at altitude per year, it might also be available as a platform to serendipitous observations not using the main telescope, such as recordings of meteor streams or the search for extra-solar planets transiting their central stars. These are areas of research in which amateur astronomers with relatively small telescopes and state-of-the-art imaging equipment can contribute.

  8. Mars Airborne Prospecting Spectrometer

    NASA Astrophysics Data System (ADS)

    Steinkraus, J. M.; Wright, M. W.; Rheingans, B. E.; Steinkraus, D. E.; George, W. P.; Aljabri, A.; Hall, J. L.; Scott, D. C.

    2012-06-01

    One novel approach towards addressing the need for innovative instrumentation and investigation approaches is the integration of a suite of four spectrometer systems to form the Mars Airborne Prospecting Spectrometers (MAPS) for prospecting on Mars.

  9. The Ionosphere Real-Time Assimilative Model, IRTAM - A Status Report

    NASA Astrophysics Data System (ADS)

    Reinisch, Bodo; Galkin, Ivan; Huang, Xueqin; Vesnin, Artem; Bilitza, Dieter

    2014-05-01

    Ionospheric models are generally unable to correctly predict the effects of space weather events on the ionosphere. Taking advantage of today's real-time availability of measured electron density profiles of the bottomside ionosphere, we have developed a technique "IRTAM" to specify real-time foF2 and hmF2 global maps. The measured data arrive at the Lowell GIRO Data Center (LGDC) from some ~70 ionosonde stations of the Global Ionosphere Radio Observatory (GIRO) [Reinisch and Galkin, 2011], usually at a 15 min cadence, and are ingested in LGDC's databases (http://ulcar.uml.edu/DIDBase/). We use the International Reference Ionosphere (IRI) electron density model [Bilitza et al., 2011] as the background model. It is an empirical monthly median model that critically depends on the correct values of the F2 layer peak height hmF2 and density NmF2 (or critical frequency foF2). The IRI model uses the so-called CCIR (or URSI) coefficients for the specification of the median foF2 and hmF2 maps. IRTAM assimilates the measured GIRO data in IRI by "adjusting" the CCIR coefficients on-the-fly. The updated maps of foF2 and hmF2 for the last 24 hours before now-time are continuously displayed on http://giro.uml.edu/RTAM [Galkin et al., 2012]. The "adjusted" bottomside profiles can be extended to the topside by using the new Vary-Chap topside profile model [Nsumei et al., 2012] which extends the profile from hmF2 to the plasmasphere. References Bilitza D., L.-A. McKinnell, B. Reinisch, and T. Fuller-Rowell (2011), The International Reference Ionosphere (IRI) today and in the future, J. Geodesy, 85:909-920, DOI 10.1007/s00190-010-0427-x Galkin, I. A., B. W. Reinisch, X. Huang, and D. Bilitza (2012), Assimilation of GIRO Data into a Real-Time IRI, Radio Sci., 47, RS0L07, doi:10.1029/2011RS004952. Nsumei, P., B. W. Reinisch, X. Huang, and D. Bilitza (2012), New Vary-Chap profile of the topside ionosphere electron density distribution for use with the IRI Model and the GIRO real time

  10. Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, volume 73

    NASA Technical Reports Server (NTRS)

    Haas, Michael R. (Editor); Davidson, Jacqueline A. (Editor); Erickson, Edwin F. (Editor)

    1995-01-01

    This symposium was organized to review the science related to NASA's Airborne Astronomy Program on the occasion of the twentieth anniversary of the Kuiper Airborne Observatory (KAO). The theme selected, 'The Galactic Ecosystem: From Gas to Stars to Dust,' was considered to capture the underlying commonality of much of the research discussed. The 8 sessions were as follows: The Interstellar Medium; The Life Cycle of the ISM in Other Galaxies; Star and Planetary System Formation; Our Planetary System: The Solar System; The Enrichment of the Interstellar Medium; The Galactic Center: A Unique Region of the Galactic Ecosystem; Instrumentation for Airborne Astronomy; KAO History and Education; and Missions and the Future of Infrared Astronomy.

  11. The Ionospheric Focused Heating experiment

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.; Siefring, C. L.; Rodriguez, P.; Haas, D. G.; Baumback, M. M.; Romero, H. A.; Solin, D. A.; Djuth, F. T.; Duncan, L. M.; Hunton, D. E.; Pollock, C. J.; Sulzer, M. P.; Tepley, C. A.; Wagner, L. S.; Goldstein, J. A.

    1995-09-01

    The Ionospheric Focused Heating rocket was launched on May 30, 1992. The sounding rocket carried an instrument and chemical payload along a trajectory that crossed the intersection of the beams from the 430-MHz incoherent scatter radar and the 5.1-MHz high-power radio wave facility near Arecibo. The release of 30 kg of CF3Br into the F region at 285 km altitude produced an ionospheric hole that acted like a convergent lens to focus the HF transmissions. The power density inside the radio beam was raised by 12 dB immediately after the release. A wide range of new processes were recorded by in situ and ground-based instruments. Measurements by instruments flying through the modified ionosphere show small-scale microcavities (<1 m) and downshifted electron plasma (Langmuir) waves inside the artificial cavity, electron density spikes at the edge of the cavity, and Langmuir waves coincident with ion gyroradius (4 m) cavities near the radio wave reflection altitude. The Arecibo incoherent scatter radar showed 20 dB or greater enhancements in ion acoustic and Langmuir wave turbulence after the 5.1-MHz radio beam was focused by the artificial lens. Enhancements in airglow from chemical reactions and, possibly, electron acceleration were recorded with optical instruments. The Ionospheric Focused Heating experiment verified some of the preflight predictions and demonstrated the value of active experiments that combine high-power radio waves with chemical releases.

  12. Magnetospheric-ionospheric Poynting flux

    NASA Technical Reports Server (NTRS)

    Thayer, Jeffrey P.

    1994-01-01

    Over the past three years of funding SRI, in collaboration with the University of Texas at Dallas, has been involved in determining the total electromagnetic energy flux into the upper atmosphere from DE-B electric and magnetic field measurements and modeling the electromagnetic energy flux at high latitudes, taking into account the coupled magnetosphere-ionosphere system. This effort has been very successful in establishing the DC Poynting flux as a fundamental quantity in describing the coupling of electromagnetic energy between the magnetosphere and ionosphere. The DE-B satellite electric and magnetic field measurements were carefully scrutinized to provide, for the first time, a large data set of DC, field-aligned, Poynting flux measurement. Investigations describing the field-aligned Poynting flux observations from DE-B orbits under specific geomagnetic conditions and from many orbits were conducted to provide a statistical average of the Poynting flux distribution over the polar cap. The theoretical modeling effort has provided insight into the observations by formulating the connection between Poynting's theorem and the electromagnetic energy conversion processes that occur in the ionosphere. Modeling and evaluation of these processes has helped interpret the satellite observations of the DC Poynting flux and improved our understanding of the coupling between the ionosphere and magnetosphere.

  13. Astronomical publications of Melbourne Observatory

    NASA Astrophysics Data System (ADS)

    Andropoulos, Jenny Ioanna

    2014-05-01

    During the second half of the 19th century and the first half of the 20th century, four well-equipped government observatories were maintained in Australia - in Melbourne, Sydney, Adelaide and Perth. These institutions conducted astronomical observations, often in the course of providing a local time service, and they also collected and collated meteorological data. As well, some of these observatories were involved at times in geodetic surveying, geomagnetic recording, gravity measurements, seismology, tide recording and physical standards, so the term "observatory" was being used in a rather broad sense! Despite the international renown that once applied to Williamstown and Melbourne Observatories, relatively little has been written by modern-day scholars about astronomical activities at these observatories. This research is intended to rectify this situation to some extent by gathering, cataloguing and analysing the published astronomical output of the two Observatories to see what contributions they made to science and society. It also compares their contributions with those of Sydney, Adelaide and Perth Observatories. Overall, Williamstown and Melbourne Observatories produced a prodigious amount of material on astronomy in scientific and technical journals, in reports and in newspapers. The other observatories more or less did likewise, so no observatory of those studied markedly outperformed the others in the long term, especially when account is taken of their relative resourcing in staff and equipment.

  14. Distributed Observatory Management

    NASA Astrophysics Data System (ADS)

    Godin, M. A.; Bellingham, J. G.

    2006-12-01

    A collection of tools for collaboratively managing a coastal ocean observatory have been developed and used in a multi-institutional, interdisciplinary field experiment. The Autonomous Ocean Sampling Network program created these tools to support the Adaptive Sampling and Prediction (ASAP) field experiment that occurred in Monterey Bay in the summer of 2006. ASAP involved the day-to-day participation of a large group of researchers located across North America. The goal of these investigators was to adapt an array of observational assets to optimize data collection and analysis. Achieving the goal required continual interaction, but the long duration of the observatory made sustained co-location of researchers difficult. The ASAP team needed a remote collaboration tool, the capability to add non-standard, interdisciplinary data sets to the overall data collection, and the ability to retrieve standardized data sets from the collection. Over the course of several months and "virtual experiments," the Ocean Observatory Portal (COOP) collaboration tool was created, along with tools for centralizing, cataloging, and converting data sets into common formats, and tools for generating automated plots of the common format data. Accumulating the data in a central location and converting the data to common formats allowed any team member to manipulate any data set quickly, without having to rely heavily on the expertise of data generators to read the data. The common data collection allowed for the development of a wide range of comparison plots and allowed team members to assimilate new data sources into derived outputs such as ocean models quickly. In addition to the standardized outputs, team members were able to produce their own specialized products and link to these through the collaborative portal, which made the experimental process more interdisciplinary and interactive. COOP was used to manage the ASAP vehicle program from its start in July 2006. New summaries were

  15. Observation and Modeling of Ionospheric Scintillation Associated with Irregularities in the Polar Ionosphere

    NASA Astrophysics Data System (ADS)

    Priyadarshi, S.; Zhang, Q. H.; Ma, Y. Z.; Wang, Y.; Zanyang, X.

    2015-12-01

    It is well understood that Ionospheric scintillation is a consequence of random electron density fluctuations present in the ionosphere. They appear at all local time of the polar regions therefore, it is essential to understand their evolution and dynamics. Using Madrigal database and South Pole Scintillation Receiver data an empirical model of ionospheric scintillation has been proposed for South Pole. Model has been validated and compared with the observations. We have investigated some interesting scintillation patterns associated with polar patches and structured flux of precipitated electrons. Our results illustrate well the irregularity structures causing ionospheric scintillation at the polar ionosphere. Limitations of our modeling approach is discussed. Keywords: Ionospheric irregularities, polar patches, scintillation.

  16. Portable coastal observatories

    USGS Publications Warehouse

    Frye, Daniel; Butman, Bradford; Johnson, Mark; von der Heydt, Keith; Lerner, Steven

    2000-01-01

    Ocean observational science is in the midst of a paradigm shift from an expeditionary science centered on short research cruises and deployments of internally recording instruments to a sustained observational science where the ocean is monitored on a regular basis, much the way the atmosphere is monitored. While satellite remote sensing is one key way of meeting the challenge of real-time monitoring of large ocean regions, new technologies are required for in situ observations to measure conditions below the ocean surface and to measure ocean characteristics not observable from space. One method of making sustained observations in the coastal ocean is to install a fiber optic cable from shore to the area of interest. This approach has the advantage of providing power to offshore instruments and essentially unlimited bandwidth for data. The LEO-15 observatory offshore of New Jersey (yon Alt et al., 1997) and the planned Katama observatory offshore of Martha's Vineyard (Edson et al., 2000) use this approach. These sites, along with other cabled sites, will play an important role in coastal ocean science in the next decade. Cabled observatories, however, have two drawbacks that limit the number of sites that are likely to be installed. First, the cable and the cable installation are expensive and the shore station needed at the cable terminus is often in an environmentally sensitive area where competing interests must be resolved. Second, cabled sites are inherently limited geographically to sites within reach of the cable, so it is difficult to cover large areas of the coastal ocean.

  17. Data Management Challenges for Airborne NASA Earth Venture Sub-Orbital Investigations

    NASA Astrophysics Data System (ADS)

    Boyer, A.; Lindsley, C.; Wright, D.; Cook, R. B.; Santhana Vannan, S. K.

    2015-12-01

    The Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC) is developing technology infrastructure to archive airborne remote sensing observations from two of NASA's Earth Venture Sub-orbital Missions. The two missions are CARVE (Carbon in Arctic Reservoirs Vulnerability Experiment) and AirMOSS (Airborne Microwave Observatory of Subcanopy and Subsurface). These missions collected over 140 TB of data from extensive ground-based and airborne instruments. The metadata and documentation requirements necessary for proper archive and dissemination of such transect-based, and often 3-dimensional, airborne data are quite different from traditional field campaign data and satellite remote sensing data streams. Staff at the ORNL DAAC have developed a metadata and data infrastructure for airborne data that enables spatial or keyword-based search and discovery, integration of related satellite- or ground-based data sets, and subsetting and visualization tools for both CARVE and AirMOSS. Here we discuss challenges, progress, and lessons learned.

  18. Next Generation Virtual Observatories

    NASA Astrophysics Data System (ADS)

    Fox, P.; McGuinness, D. L.

    2008-12-01

    Virtual Observatories (VO) are now being established in a variety of geoscience disciplines beyond their origins in Astronomy and Solar Physics. Implementations range from hydrology and environmental sciences to solid earth sciences. Among the goals of VOs are to provide search/ query, access and use of distributed, heterogeneous data resources. With many of these goals being met and usage increasing, new demands and requirements are arising. In particular there are two of immediate and pressing interest. The first is use of VOs by non-specialists, especially for information products that go beyond the usual data, or data products that are sought for scientific research. The second area is citation and attribution of artifacts that are being generated by VOs. In some sense VOs are re-publishing (re-packaging, or generating new synthetic) data and information products. At present only a few VOs address this need and it is clear that a comprehensive solution that includes publishers is required. Our work in VOs and related semantic data framework and integration areas has lead to a view of the next generation of virtual observatories which the two above-mentioned needs as well as others that are emerging. Both of the needs highlight a semantic gap, i.e. that the meaning and use for a user or users beyond the original design intention is very often difficult or impossible to bridge. For example, VOs created for experts with complex, arcane or jargon vocabularies are not accessible to the non-specialist and further, information products the non-specialist may use are not created or considered for creation. In the second case, use of a (possibly virtual) data or information product (e.g. an image or map) as an intellectual artifact that can be accessed as part of the scientific publication and review procedure also introduces terminology gaps, as well as services that VOs may need to provide. Our supposition is that formalized methods in semantics and semantic web

  19. Strasbourg Observatory Archives Revisited

    NASA Astrophysics Data System (ADS)

    Heck, A.

    2002-12-01

    Official talks in France and Germany after World War I were generally of hatred and revenge. Strasbourg Observatory had just changed nationality (from Prussian to French) for the first time (this would happen again at the outbreak of WWII and after the conflict). Documents show that astronomers did not share the general attitude. For example the inventory book started in German was continued in French after 1918. It is moving to see those different handwritings in two different languages on the same pages -- making of that book a unique document in various respects, but also reminding us that the native language of the region was in fact Alsacian.

  20. ESO's Two Observatories Merge

    NASA Astrophysics Data System (ADS)

    2005-02-01

    On February 1, 2005, the European Southern Observatory (ESO) has merged its two observatories, La Silla and Paranal, into one. This move will help Europe's prime organisation for astronomy to better manage its many and diverse projects by deploying available resources more efficiently where and when they are needed. The merged observatory will be known as the La Silla Paranal Observatory. Catherine Cesarsky, ESO's Director General, comments the new development: "The merging, which was planned during the past year with the deep involvement of all the staff, has created unified maintenance and engineering (including software, mechanics, electronics and optics) departments across the two sites, further increasing the already very high efficiency of our telescopes. It is my great pleasure to commend the excellent work of Jorge Melnick, former director of the La Silla Observatory, and of Roberto Gilmozzi, the director of Paranal." ESO's headquarters are located in Garching, in the vicinity of Munich (Bavaria, Germany), and this intergovernmental organisation has established itself as a world-leader in astronomy. Created in 1962, ESO is now supported by eleven member states (Belgium, Denmark, Finland, France, Germany, Italy, The Netherlands, Portugal, Sweden, Switzerland, and the United Kingdom). It operates major telescopes on two remote sites, all located in Chile: La Silla, about 600 km north of Santiago and at an altitude of 2400m; Paranal, a 2600m high mountain in the Atacama Desert 120 km south of the coastal city of Antofagasta. Most recently, ESO has started the construction of an observatory at Chajnantor, a 5000m high site, also in the Atacama Desert. La Silla, north of the town of La Serena, has been the bastion of the organization's facilities since 1964. It is the site of two of the most productive 4-m class telescopes in the world, the New Technology Telescope (NTT) - the first major telescope equipped with active optics - and the 3.6-m, which hosts HARPS

  1. NASA's Heliophysics System Observatory

    NASA Astrophysics Data System (ADS)

    Clarke, Steven

    2016-04-01

    NASA formulates and implements a national research program for understanding the Sun and its interactions with the Earth and the solar system and how these phenomena impact life and society. This research provides theory, data, and modeling development services to national and international space weather efforts utilizing a coordinated and complementary fleet of spacecraft, called the Heliophysics System Observatory (HSO), to understand the Sun and its interactions with Earth and the solar system, including space weather. This presentation will focus on NASA's role in space weather research and the contributions the agency continues to provide to the science of space weather, leveraging inter-agency and international collaborations for the benefit of society.

  2. The energetics of Titan's ionosphere

    NASA Astrophysics Data System (ADS)

    Roboz, A.; Nagy, A. F.

    1994-02-01

    We have developed a comprehensive model to study the dynamics and energetics of the ionosphere of Titan. We solved the one-dimensional, time-dependent, coupled continuity and momentum equations for several ion species, together with single ion and electron energy equations, in order to calculate density, velocity, and temperature profiles. Calculations were carried out for several cases corresponding to different local times and configurations of the Titan-Saturn system. In our model the effects of horizontal magnetic fields were assumed to be negligible, except for their effect on reducing the electron and ion thermal conductivities and inhibiting vertical transport in the subram region. The ionospheric density peak was found to be at an altitude of about 1100 km, in accordance with earlier model calculations. The ionosphere is chemically controlled below an altitude of about 1500 km. Above this level, ion densities differ significantly from their chemical equilibrium values due to strong upward ion velocities. Heat is deposited in a narrow region around the ionospheric peak, resulting in temperature profiles increasing sharply and reaching nearly constant values of 800-1000 deg K for electrons and 300 deg K for ions in the topside, assuming conditions appropriate for the wake region. In the subram region magnetic correction factors make the electron heat conductivities negligible, resulting in electron temperatures increasing strongly with altitude and reaching values in the order of 5000 deg K at our upper boundary located at 2200 km. Ion chemical heating is found to play an important role in shaping the ion energy balance in Titan's ionosphere.

  3. Stratospheric Observatory for Infrared Astronomy (SOFIA) science rationale

    NASA Technical Reports Server (NTRS)

    Davidson, Jacqueline A.; Erickson, Edwin F.

    1989-01-01

    SOFIA, a proposed 3-meter class telescope in a Boeing 747 aircraft, would have the ability to make astronomical observations over a wavelength range from 0.3 microns to 1.6mm. Relative to the KAO (Kuiper Airborne Observatory) the larger telescope on SOFIA would provide a factor of 10 improvement in sensitivity for compact sources and a factor of 3 improvement in (diffraction-limited) angular resolution at wavelengths beyond 30 microns. In addition, SOFIA will retain the major features of the KAO which have made the airborne astronomy program so successful. Among these are continuous in-flight access to focal plane instruments while flying at or above 41,000 ft altitude; pointing stability of 0.2 arcseconds; and mobility and scheduling flexibility to accommodate targets of opportunity such as comets, eclipses, occultations, and novae.

  4. Byurakan Astrophysical Observatory

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.

    2016-09-01

    This booklet is devoted to NAS RA V. Ambartsumian Byurakan Astrophysical Observatory and is aimed at people interested in astronomy and BAO, pupils and students, BAO visitors and others. The booklet is made as a visiting card and presents concise and full information about BAO. A brief history of BAO, the biography of the great scientist Viktor Ambartsumian, brief biographies of 13 other deserved scientists formerly working at BAO (B.E. Markarian, G.A. Gurzadyan, L.V. Mirzoyan, M.A. Arakelian, et al.), information on BAO telescopes (2.6m, 1m Schmidt, etc.) and other scientific instruments, scientific library and photographic plate archive, Byurakan surveys (including the famous Markarian Survey included in the UNESCO Memory of the World International Register), all scientific meetings held in Byurakan, international scientific collaboration, data on full research staff of the Observatory, as well as former BAO researchers, who have moved to foreign institutions are given in the booklet. At the end, the list of the most important books published by Armenian astronomers and about them is given.

  5. GPM Core Observatory Launch Animation

    NASA Video Gallery

    This animation depicts the launch of the Global Precipitation Measurement (GPM) Core Observatory satellite from Tanegashima Space Center, Japan. The launch is currently scheduled for Feb. 27, 2014....

  6. Observations of solar-wind-driven progression of interplanetary magnetic field B{sub Y}-related dayside ionospheric disturbances

    SciTech Connect

    Stauning, P.; Friis-Christensen, E.; Clauer, C.R.

    1995-05-01

    Observations from August 2, and 3, 1991, of poleward progressing, dayside convection disturbances accompanied by geomagnetic perturbations and ionospheric radio wave absorption have been analyzed and compared to variations in the solar wind parameters as observed from the IMP 8 satellite. The convection disturbances appear to start at dayside cusp latitudes from where they progress antisunward to high latitudes. The reported observations have enabled calculations of the progression directions and velocities and precise estimates of the delays between solar wind variations as measured by the IMP 8 satellite and ionospheric convection changes as observed from an array of polar magnetic observatories. The progressing ionospheric disturbance events occur during intervals of southward interplanetary magnetic fields (negative interplanetary magnetic field (IMF) B{sub Z} component); they are found to be closely related to variations of the east-west component B{sub Y} of the IMF. The close coupling between the solar wind and the polar ionosphere(s) is explained in an open magnetospheric model in which the geomagnetic field extending from a localized region of the dayside polar cap merges with the southward interplanetary field. Variations in the IMF B{sub Y} component are reproduced in corresponding modulations of the east-west component of the plasma flow at the ionospheric foot points of the connecting `open` field lines. The perturbations of the plasma flow persist while the open field lines are convected with the ionospheric plasma across part of the dayside polar cap. The observed geomagnetic perturbations result from the combined effects of field-aligned currents and horizontal ionospheric currents, notably the convection-related Hall currents. The associated radio wave absorption events are explained as the result of E region electron heating by the horizontal electric fields associated with the convection enhancements. 48 refs., 16 figs., 3 tabs.

  7. Preface: International Reference Ionosphere - Progress in Ionospheric Modelling

    NASA Technical Reports Server (NTRS)

    Bilitza Dieter; Reinisch, Bodo

    2010-01-01

    The international reference ionosphere (lRI) is the internationally recommended empirical model for the specification of ionospheric parameters supported by the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI) and recognized by the International Standardization Organization (ISO). IRI is being continually improved by a team of international experts as new data become available and better models are being developed. This issue chronicles the latest phase of model updates as reported during two IRI-related meetings. The first was a special session during the Scientific Assembly of the Committee of Space Research (COSPAR) in Montreal, Canada in July 2008 and the second was an IRI Task Force Activity at the US Air Force Academy in Colorado Springs in May 2009. This work led to several improvements and additions of the model which will be included in the next version, IRI-201O. The issue is divided into three sections focusing on the improvements made in the topside ionosphere, the F-peak, and the lower ionosphere, respectively. This issue would not have been possible without the reviewing efforts of many individuals. Each paper was reviewed by two referees. We thankfully acknowledge the contribution to this issue made by the following reviewers: Jacob Adeniyi, David Altadill, Eduardo Araujo, Feza Arikan, Dieter Bilitza, Jilijana Cander, Bela Fejer, Tamara Gulyaeva, Manuel Hermindez-Pajares, Ivan Kutiev, John MacDougal, Leo McNamara, Bruno Nava, Olivier Obrou, Elijah Oyeyemi, Vadym Paznukhov, Bodo Reinisch, John Retterer, Phil Richards, Gary Sales, J.H. Sastri, Ludger Scherliess, Iwona Stanislavska, Stamir Stankov, Shin-Yi Su, Manlian Zhang, Y ongliang Zhang, and Irina Zakharenkova. We are grateful to Peggy Ann Shea for her final review and guidance as the editor-in-chief for special issues of Advances in Space Research. We thank the authors for their timely submission and their quick response to the reviewer comments and humbly

  8. Interaction of Titan's ionosphere with Saturn's magnetosphere.

    PubMed

    Coates, Andrew J

    2009-02-28

    Titan is the only Moon in the Solar System with a significant permanent atmosphere. Within this nitrogen-methane atmosphere, an ionosphere forms. Titan has no significant magnetic dipole moment, and is usually located inside Saturn's magnetosphere. Atmospheric particles are ionized both by sunlight and by particles from Saturn's magnetosphere, mainly electrons, which reach the top of the atmosphere. So far, the Cassini spacecraft has made over 45 close flybys of Titan, allowing measurements in the ionosphere and the surrounding magnetosphere under different conditions. Here we review how Titan's ionosphere and Saturn's magnetosphere interact, using measurements from Cassini low-energy particle detectors. In particular, we discuss ionization processes and ionospheric photoelectrons, including their effect on ion escape from the ionosphere. We also discuss one of the unexpected discoveries in Titan's ionosphere, the existence of extremely heavy negative ions up to 10000amu at 950km altitude. PMID:19073464

  9. The dynamics of the Venus ionosphere

    NASA Technical Reports Server (NTRS)

    Miller, K. L.

    1988-01-01

    Data from the Pioneer-Venus orbiter has demonstrated the importance of understanding ion dynamics in the Venus ionosphere. The analysis of the data has shown that during solar maximum the topside Venus ionosphere in the dark hemisphere is generated almost entirely on the dayside of the planet during solar maximum, and flows with supersonic velocities across the terminator into the nightside. The flow field in the ionosphere is mainly axially-symmetric about the sun-Venus axis, as are most measured ionospheric quantities. The primary data base used consisted of the ion velocity measurements made by the RPA during three years that periapsis of the orbiter was maintained in the Venus ionosphere. Examples of ion velocities were published and modeled. This research examined the planetary flow patterns measured in the Venus ionosphere, and the physical implications of departures from the mean flow.

  10. Interaction of Titan's ionosphere with Saturn's magnetosphere.

    PubMed

    Coates, Andrew J

    2009-02-28

    Titan is the only Moon in the Solar System with a significant permanent atmosphere. Within this nitrogen-methane atmosphere, an ionosphere forms. Titan has no significant magnetic dipole moment, and is usually located inside Saturn's magnetosphere. Atmospheric particles are ionized both by sunlight and by particles from Saturn's magnetosphere, mainly electrons, which reach the top of the atmosphere. So far, the Cassini spacecraft has made over 45 close flybys of Titan, allowing measurements in the ionosphere and the surrounding magnetosphere under different conditions. Here we review how Titan's ionosphere and Saturn's magnetosphere interact, using measurements from Cassini low-energy particle detectors. In particular, we discuss ionization processes and ionospheric photoelectrons, including their effect on ion escape from the ionosphere. We also discuss one of the unexpected discoveries in Titan's ionosphere, the existence of extremely heavy negative ions up to 10000amu at 950km altitude.

  11. Using Radio-Induced Aurora to Observe Ionospheric Irregularities

    NASA Astrophysics Data System (ADS)

    Bernhardt, P.; Gondarenko, N.; Guzdar, P.; Huba, J.; Ossakow, S.; Djuth, F.; Tepley, C.; Sulzer, M.; Kagan, L.; Kelley, M.

    Two-dimensional images of F- and E- layers have been obtained using the technique called radio-induced aurora (RIA). This technique makes the plasma layers glow in the ionosphere glow when being stimulated by high power radio waves. Normally the irregularities in the ionosphere do not radiate strong enough visible emissions to be observed from the ground. Experiments at Arecibo Observatory in Puerto Rico and the SURA facility in Russia have shown that the plasma structures can be made to glow at 630.0 nm, 557.7 nm and other wavelengths by illuminating them by HF radio waves with effective radiated powers of 80 megawatts. The regions of the sporadic-E layers that have electron densities greater than the critical density for reflection of the radio waves emit electrons that collide with and excite atmospheric atomic oxygen and molecular nitrogen. A charge-coupled-device (CCD) imager located on the ground is used to capture images of the glowing E and F-region structures. The camera exposure- times were in the range of 15 to 45 seconds. The images obtained using this technique show a wide variety of both field-aligned and wind-aligned irregularities. Some layers cover the antenna pattern cone illuminated by the radio wave beam. Other layers show strong modulations by both plasma and neutral instabilities. Two-dimensional computer simulations of the coupling between neutral winds, electric fields and the ion layers simulate the structure in the images.

  12. Electrical discharge from a thundercloud top to the lower ionosphere.

    PubMed

    Pasko, Victor P; Stanley, Mark A; Mathews, John D; Inan, Umran S; Wood, Troy G

    2002-03-14

    For over a century, numerous undocumented reports have appeared about unusual large-scale luminous phenomena above thunderclouds and, more than 80 years ago, it was suggested that an electrical discharge could bridge the gap between a thundercloud and the upper atmosphere. Since then, two classes of vertically extensive optical flashes above thunderclouds have been identified-sprites and blue jets. Sprites initiate near the base of the ionosphere, develop very rapidly downwards at speeds which can exceed 107 m s-1 (ref. 15), and assume many different geometrical forms. In contrast, blue jets develop upwards from cloud tops at speeds of the order of 105 m s-1 and are characterized by a blue conical shape. But no experimental data related to sprites or blue jets have been reported which conclusively indicate that they establish a direct path of electrical contact between a thundercloud and the lower ionosphere. Here we report a video recording of a blue jet propagating upwards from a thundercloud to an altitude of about 70 km, taken at the Arecibo Observatory, Puerto Rico. Above an altitude of 42 km-normally the upper limit for blue jets and the lower terminal altitude for sprites-the flash exhibited some features normally observed in sprites. As we observed this phenomenon above a relatively small thunderstorm cell, we speculate that it may be common and therefore represent an unaccounted for component of the global electric circuit. PMID:11894087

  13. Sodankylä ionospheric tomography dataset 2003-2014

    NASA Astrophysics Data System (ADS)

    Norberg, J.; Roininen, L.; Kero, A.; Raita, T.; Ulich, T.; Markkanen, M.; Juusola, L.; Kauristie, K.

    2015-12-01

    Sodankylä Geophysical Observatory has been operating a tomographic receiver network and collecting the produced data since 2003. The collected dataset consists of phase difference curves measured from Russian COSMOS dual-frequency (150/400 MHz) low-Earth-orbit satellite signals, and tomographic electron density reconstructions obtained from these measurements. In this study vertical total electron content (VTEC) values are integrated from the reconstructed electron densities to make a qualitative and quantitative analysis to validate the long-term performance of the tomographic system. During the observation period, 2003-2014, there were three-to-five operational stations at the Fenno-Scandinavian sector. Altogether the analysis consists of around 66 000 overflights, but to ensure the quality of the reconstructions, the examination is limited to cases with descending (north to south) overflights and maximum elevation over 60°. These constraints limit the number of overflights to around 10 000. Based on this dataset, one solar cycle of ionospheric vertical total electron content estimates is constructed. The measurements are compared against International Reference Ionosphere IRI-2012 model, F10.7 solar flux index and sunspot number data. Qualitatively the tomographic VTEC estimate corresponds to reference data very well, but the IRI-2012 model are on average 40 % higher of that of the tomographic results.

  14. The Sudbury Neutrino Observatory

    NASA Astrophysics Data System (ADS)

    Bellerive, A.; Klein, J. R.; McDonald, A. B.; Noble, A. J.; Poon, A. W. P.

    2016-07-01

    This review paper provides a summary of the published results of the Sudbury Neutrino Observatory (SNO) experiment that was carried out by an international scientific collaboration with data collected during the period from 1999 to 2006. By using heavy water as a detection medium, the SNO experiment demonstrated clearly that solar electron neutrinos from 8B decay in the solar core change into other active neutrino flavors in transit to Earth. The reaction on deuterium that has equal sensitivity to all active neutrino flavors also provides a very accurate measure of the initial solar flux for comparison with solar models. This review summarizes the results from three phases of solar neutrino detection as well as other physics results obtained from analyses of the SNO data.

  15. LCOGT network observatory operations

    NASA Astrophysics Data System (ADS)

    Pickles, Andrew; Hjelstrom, Annie; Boroson, Todd; Burleson, Ben; Conway, Patrick; De Vera, Jon; Elphick, Mark; Haworth, Brian; Rosing, Wayne; Saunders, Eric; Thomas, Doug; White, Gary; Willis, Mark; Walker, Zach

    2014-08-01

    We describe the operational capabilities of the Las Cumbres Observatory Global Telescope Network. We summarize our hardware and software for maintaining and monitoring network health. We focus on methodologies to utilize the automated system to monitor availability of sites, instruments and telescopes, to monitor performance, permit automatic recovery, and provide automatic error reporting. The same jTCS control system is used on telescopes of apertures 0.4m, 0.8m, 1m and 2m, and for multiple instruments on each. We describe our network operational model, including workloads, and illustrate our current tools, and operational performance indicators, including telemetry and metrics reporting from on-site reductions. The system was conceived and designed to establish effective, reliable autonomous operations, with automatic monitoring and recovery - minimizing human intervention while maintaining quality. We illustrate how far we have been able to achieve that.

  16. The virtual observatory registry

    NASA Astrophysics Data System (ADS)

    Demleitner, M.; Greene, G.; Le Sidaner, P.; Plante, R. L.

    2014-11-01

    In the Virtual Observatory (VO), the Registry provides the mechanism with which users and applications discover and select resources-typically, data and services-that are relevant for a particular scientific problem. Even though the VO adopted technologies in particular from the bibliographic community where available, building the Registry system involved a major standardisation effort, involving about a dozen interdependent standard texts. This paper discusses the server-side aspects of the standards and their application, as regards the functional components (registries), the resource records in both format and content, the exchange of resource records between registries (harvesting), as well as the creation and management of the identifiers used in the system based on the notion of authorities. Registry record authors, registry operators or even advanced users thus receive a big picture serving as a guideline through the body of relevant standard texts. To complete this picture, we also mention common usage patterns and open issues as appropriate.

  17. Hanohano: Hawaiian antineutrino observatory

    NASA Astrophysics Data System (ADS)

    Maricic, Jelena; Hanohano Collaboration

    2010-01-01

    Design studies are underway for the deep ocean antineutrino observatory Hanohano. The 10 kton monolitic underwater detector will be able to make precision measurement of neutrino mixing parameters (including θ13 and neutrino mass hierarchy) if stationed around 60 km offshore, from the nuclear reactor. Hanohano will be a mobile detector and placing it in a mid-Pacific location will provide the first ever flux measurement of geoneutrinos (antineutrinos emitted in the radioactive decay series of uranium and thorium), coming from the Earth's mantle and perform a sensitivity search for a hypothetical natural fission reactor in the Earth's core. Additional deployment at a different mid-ocean location will lead to tests of lateral heterogeneity of uranium and thorium in the Earth's mantle. These measurements would provide an important insight into deep-Earth geophysics, mantle composition and understanding of the Earth's heat flow and sources of energy inside the Earth.

  18. Orbiting Carbon Observatory

    NASA Technical Reports Server (NTRS)

    Miller, Charles E.

    2005-01-01

    Human impact on the environment has produced measurable changes in the geological record since the late 1700s. Anthropogenic emissions of CO2 today may cause the global climate to depart for its natural behavior for many millenia. CO2 is the primary anthropogenic driver of climate change. The Orbiting Carbon Observatory goals are to help collect measurements of atmospheric CO2, answering questions such as why the atmospheric CO2 buildup varies annually, the roles of the oceans and land ecosystems in absorbing CO2, the roles of North American and Eurasian sinks and how these carbon sinks respond to climate change. The present carbon cycle, CO2 variability, and climate uncertainties due atmospheric CO2 uncertainties are highlighted in this presentation.

  19. Airborne data acquisition techniques

    SciTech Connect

    Arro, A.A.

    1980-01-01

    The introduction of standards on acceptable procedures for assessing building heat loss has created a dilemma for the contractor performing airborne thermographic surveys. These standards impose specifications on instrumentation, data acquisition, recording, interpretation, and presentation. Under the standard, the contractor has both the obligation of compliance and the requirement of offering his services at a reasonable price. This paper discusses the various aspects of data acquisition for airborne thermographic surveys and various techniques to reduce the costs of this operation. These techniques include the calculation of flight parameters for economical data acquisition, the selection and use of maps for mission planning, and the use of meteorological forecasts for flight scheduling and the actual execution of the mission. The proper consideration of these factors will result in a cost effective data acquisition and will place the contractor in a very competitive position in offering airborne thermographic survey services.

  20. A long-term study of the impact of solar flares on ionospheric characteristics measured by digisondes and GNSS receivers

    NASA Astrophysics Data System (ADS)

    Tripathi, Sharad Chandra; Haralambous, Haris; Das, Tanmay

    2016-07-01

    Solar Flares are highly transient phenomena radiating over a wide spectrum of wavelengths with EUV and X-rays imposing the most significant effect on ionospheric characteristics. This study presents an attempt to examine qualitatively and quantitatively these effects as measured by digisondes and GNSS receivers on a global scale. For this purpose we have divided the whole globe in three sectors (American, African-European and Asian) based on longitude. We have extracted data for ionospheric characteristics by scaling, manually, the ionograms being provided by DIDBase (Digital Ionogram Database) as provided by the Global Ionospheric Radio Observatory (GIRO) during X-class flares for an approximate period of a solar cycle . We have also used TEC data extracted from GPS observations from collocated IGS Stations. Spectral analysis of Solar Flares are added to the methodology to compare the effects in terms of spectral characteristics.

  1. Global geodetic observatories

    NASA Astrophysics Data System (ADS)

    Boucher, Claude; Pearlman, Mike; Sarti, Pierguido

    2015-01-01

    Global geodetic observatories (GGO) play an increasingly important role both for scientific and societal applications, in particular for the maintenance and evolution of the reference frame and those applications that rely on the reference frame for their viability. The International Association of Geodesy (IAG), through the Global Geodetic Observing System (GGOS), is fully involved in coordinating the development of these systems and ensuring their quality, perenniality and accessibility. This paper reviews the current role, basic concepts, and some of the critical issues associated with the GGOs, and advocates for their expansion to enhance co-location with other observing techniques (gravity, meteorology, etc). The historical perspective starts with the MERIT campaign, followed by the creation of international services (IERS, IGS, ILRS, IVS, IDS, etc). It provides a basic definition of observing systems and observatories and the build up of the international networks and the role of co-locations in geodesy and geosciences and multi-technique processing and data products. This paper gives special attention to the critical topic of local surveys and tie vectors among co-located systems in sites; the agreement of space geodetic solutions and the tie vectors now place one of the most significant limitations on the quality of integrated data products, most notably the ITRF. This topic focuses on survey techniques, extrapolation to instrument reference points, computation techniques, systematic biases, and alignment of the individual technique reference frames into ITRF. The paper also discusses the design, layout and implementation of network infrastructure, including the role of GGOS and the benefit that would be achieved with better standardization and international governance.

  2. Sudbury Neutrino Observatory

    SciTech Connect

    Beier, E.W.

    1992-03-01

    This document is a technical progress report on work performed at the University of Pennsylvania during the current year on the Sudbury Neutrino Observatory project. The motivation for the experiment is the measurement of neutrinos emitted by the sun. The Sudbury Neutrino Observatory (SNO) is a second generation dedicated solar neutrino experiment which will extend the results of our work with the Kamiokande II detector by measuring three reactions of neutrinos rather than the single reaction measured by the Kamiokande experiment. The collaborative project includes physicists from Canada, the United Kingdom, and the United States. Full funding for the construction of this facility was obtained in January 1990, and its construction is estimated to take five years. The motivation for the SNO experiment is to study the fundamental properties of neutrinos, in particular the mass and mixing parameters, which remain undetermined after decades of experiments in neutrino physics utilizing accelerators and reactors as sources of neutrinos. To continue the study of neutrino properties it is necessary to use the sun as a neutrino source. The long distance to the sun makes the search for neutrino mass sensitive to much smaller mass than can be studied with terrestrial sources. Furthermore, the matter density in the sun is sufficiently large to enhance the effects of small mixing between electron neutrinos and mu or tau neutrinos. This experiment, when combined with the results of the radiochemical {sup 37}Cl and {sup 71}Ga experiments and the Kamiokande II experiment, should extend our knowledge of these fundamental particles, and as a byproduct, improve our understanding of energy generation in the sun.

  3. Ionospheric Change and Solar EUV Irradiance

    NASA Astrophysics Data System (ADS)

    Sojka, J. J.; David, M.; Jensen, J. B.; Schunk, R. W.

    2011-12-01

    The ionosphere has been quantitatively monitored for the past six solar cycles. The past few years of observations are showing trends that differ from the prior cycles! Our good statistical relationships between the solar radio flux index at 10.7 cm, the solar EUV Irradiance, and the ionospheric F-layer peak density are showing indications of divergence! Present day discussion of the Sun-Earth entering a Dalton Minimum would suggest change is occurring in the Sun, as the driver, followed by the Earth, as the receptor. The dayside ionosphere is driven by the solar EUV Irradiance. But different components of this spectrum affect the ionospheric layers differently. For a first time the continuous high cadence EUV spectra from the SDO EVE instrument enable ionospheric scientists the opportunity to evaluate solar EUV variability as a driver of ionospheric variability. A definitive understanding of which spectral components are responsible for the E- and F-layers of the ionosphere will enable assessments of how over 50 years of ionospheric observations, the solar EUV Irradiance has changed. If indeed the evidence suggesting the Sun-Earth system is entering a Dalton Minimum periods is correct, then the comprehensive EVE solar EUV Irradiance data base combined with the ongoing ionospheric data bases will provide a most fortuitous fiduciary reference baseline for Sun-Earth dependencies. Using the EVE EUV Irradiances, a physics based ionospheric model (TDIM), and 50 plus years of ionospheric observation from Wallops Island (Virginia) the above Sun-Earth ionospheric relationship will be reported on.

  4. Midlatitude ionospheric dynamics and disturbances: Introduction

    NASA Astrophysics Data System (ADS)

    Kintner, Paul M., Jr.; Coster, Anthea J.; Fuller-Rowell, Tim; Mannucci, Anthony J.; Mendillo, Michael; Heelis, Roderick

    Recent discoveries have demonstrated that the ionosphere responds over regions extending from the equator to the poles during geomagnetic storms and experiences the most extreme changes at midlatitudes. The midlatitude ionosphere was first studied during the "discovery era" of radio physics and space flight 50 or more years ago, but for the past three decades the polar and tropical ionosphere have dominated scientific activity, resulting in the false impression that the midlatitude ionosphere was an uninteresting region of known morphology and well-understood processes. During the past five years, however, the ability to image the ionosphere and thermosphere with large arrays of ground-based GPS receivers and satellite-borne UV imagers changed this viewpoint dramatically and led to the inception of the Chapman Conference on Mid-Latitude Ionospheric Dynamics and Disturbances (MIDD) and to this monograph. The most dramatic changes in ionospheric content occur at midlatitudes, not at high or equatorial latitudes. The most extreme examples of ionospheric total electron content (TEC) perturbations occur at midlatitudes during geomagnetic storms, where TEC can change by factors of three to ten over the duration of a magnetic storm. The ionosphere responds to magnetic storms over regions extending from the equator to the poles, where huge volumes of plasma are produced and transported polewards. Sharp gradients in ionospheric content, extending thousands of kilometers, are created by unknown factors. These gradients spawn irregularities that together impact users of RF signals, either transiting across or reflecting from the ionosphere. At higher altitudes, dramatic changes in the ionosphere are accompanied by movement and transport of the plasmasphere.

  5. HAARP-Induced Ionospheric Ducts

    SciTech Connect

    Milikh, Gennady; Vartanyan, Aram

    2011-01-04

    It is well known that strong electron heating by a powerful HF-facility can lead to the formation of electron and ion density perturbations that stretch along the magnetic field line. Those density perturbations can serve as ducts for ELF waves, both of natural and artificial origin. This paper presents observations of the plasma density perturbations caused by the HF-heating of the ionosphere by the HAARP facility. The low orbit satellite DEMETER was used as a diagnostic tool to measure the electron and ion temperature and density along the satellite orbit overflying close to the magnetic zenith of the HF-heater. Those observations will be then checked against the theoretical model of duct formation due to HF-heating of the ionosphere. The model is based on the modified SAMI2 code, and is validated by comparison with well documented experiments.

  6. Ionospheric redistribution during geomagnetic storms

    PubMed Central

    Immel, T J; Mannucci, A J

    2013-01-01

    [1]The abundance of plasma in the daytime ionosphere is often seen to grow greatly during geomagnetic storms. Recent reports suggest that the magnitude of the plasma density enhancement depends on the UT of storm onset. This possibility is investigated over a 7year period using global maps of ionospheric total electron content (TEC) produced at the Jet Propulsion Laboratory. The analysis confirms that the American sector exhibits, on average, larger storm time enhancement in ionospheric plasma content, up to 50% in the afternoon middle-latitude region and 30% in the vicinity of the high-latitude auroral cusp, with largest effect in the Southern Hemisphere. We investigate whether this effect is related to the magnitude of the causative magnetic storms. Using the same advanced Dst index employed to sort the TEC maps into quiet and active (Dst<−100 nT) sets, we find variation in storm strength that corresponds closely to the TEC variation but follows it by 3–6h. For this and other reasons detailed in this report, we conclude that the UT-dependent peak in storm time TEC is likely not related to the magnitude of external storm time forcing but more likely attributable to phenomena such as the low magnetic field in the South American region. The large Dst variation suggests a possible system-level effect of the observed variation in ionospheric storm response on the measured strength of the terrestrial ring current, possibly connected through UT-dependent modulation of ion outflow. PMID:26167429

  7. Lithosphere - Atmosphere - Ionosphere Circuit Model

    NASA Astrophysics Data System (ADS)

    Kereselidze, Z.; Kachakhidze, N.; Kachakhidze, M.

    2012-04-01

    There are offered possibilities of original LAI circuit model. The problem concerns of existence of self-generated electromagnetic oscillations in the segment of LAI system, which are results of tectonic stress developing in the focus area of expected earthquake. By this model the main (lowest) frequency of these electromagnetic oscillations frequency spectrum is expressed analytically by following formula: ω = β c l where β(ω) is the coefficient depended on the frequency and geological characteristics of the medium and approximate to one, c-is the speed of light, and l- the length of the fault in the focus of the expected earthquake. On the base of relevant diagnosis of experimental data, the model gives us possibility to discuss the problem about location, time of occurrence and intensity of an expected earthquake with certain accuracy. In addition to it, considered model does not block the fall-unstable model of earthquake preparing and electromagnetic phenomena accompanied earthquake preparing process. On the contrary, the imagination of physical picture may be simplified in the separate stage of earthquakes preparing. Namely, it is possible to reliably separate series of foreshocks and aftershocks. By this point of view, the certain optimism about using of EM emission as earthquake precursor of full value may be expressed. The base of such optimism is developing of various phenomena connected to VLF emission many times fixed in the surroundings of epicentral area and cosmic space (changing of intensity of electro-telluric current, perturbations of geomagnetic field in forms of irregular pulsations or regular short-period pulsations, perturbations of atmospheric electric field, perturbations of ionosphere critical frequency and TEC, variations of height of lower ionosphere, parameters of ionospheric medium: changing of specific dielectric conductivity and spectrum of MGD waves in it, atmospheric-ionospheric discharging and etc.).

  8. Ionospheric very low frequency transmitter

    SciTech Connect

    Kuo, Spencer P.

    2015-02-15

    The theme of this paper is to establish a reliable ionospheric very low frequency (VLF) transmitter, which is also broad band. Two approaches are studied that generate VLF waves in the ionosphere. The first, classic approach employs a ground-based HF heater to directly modulate the high latitude ionospheric, or auroral electrojet. In the classic approach, the intensity-modulated HF heater induces an alternating current in the electrojet, which serves as a virtual antenna to transmit VLF waves. The spatial and temporal variations of the electrojet impact the reliability of the classic approach. The second, beat-wave approach also employs a ground-based HF heater; however, in this approach, the heater operates in a continuous wave mode at two HF frequencies separated by the desired VLF frequency. Theories for both approaches are formulated, calculations performed with numerical model simulations, and the calculations are compared to experimental results. Theory for the classic approach shows that an HF heater wave, intensity-modulated at VLF, modulates the electron temperature dependent electrical conductivity of the ionospheric electrojet, which, in turn, induces an ac electrojet current. Thus, the electrojet becomes a virtual VLF antenna. The numerical results show that the radiation intensity of the modulated electrojet decreases with an increase in VLF radiation frequency. Theory for the beat wave approach shows that the VLF radiation intensity depends upon the HF heater intensity rather than the electrojet strength, and yet this approach can also modulate the electrojet when present. HF heater experiments were conducted for both the intensity modulated and beat wave approaches. VLF radiations were generated and the experimental results confirm the numerical simulations. Theory and experimental results both show that in the absence of the electrojet, VLF radiation from the F-region is generated via the beat wave approach. Additionally, the beat wave approach

  9. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Specifications and preliminary design of an Airborne Oceanographic Lidar (AOL) system, which is to be constructed for installation and used on a NASA Wallops Flight Center (WFC) C-54 research aircraft, are reported. The AOL system is to provide an airborne facility for use by various government agencies to demonstrate the utility and practicality of hardware of this type in the wide area collection of oceanographic data on an operational basis. System measurement and performance requirements are presented, followed by a description of the conceptual system approach and the considerations attendant to its development. System performance calculations are addressed, and the system specifications and preliminary design are presented and discussed.

  10. Airborne rain mapping radar

    NASA Technical Reports Server (NTRS)

    Wilson, W. J.; Parks, G. S.; Li, F. K.; Im, K. E.; Howard, R. J.

    1988-01-01

    An airborne scanning radar system for remote rain mapping is described. The airborne rain mapping radar is composed of two radar frequency channels at 13.8 and 24.1 GHz. The radar is proposed to scan its antenna beam over + or - 20 deg from the antenna boresight; have a swath width of 7 km; a horizontal spatial resolution at nadir of about 500 m; and a range resolution of 120 m. The radar is designed to be applicable for retrieving rainfall rates from 0.1-60 mm/hr at the earth's surface, and for measuring linear polarization signatures and raindrop's fall velocity.

  11. Rolloff Roof Observatory Construction (Abstract)

    NASA Astrophysics Data System (ADS)

    Ulowetz, J. H.

    2015-12-01

    (Abstract only) Lessons learned about building an observatory by someone with limited construction experience, and the advantages of having one for imaging and variable star studies. Sample results shown of composite light curves for cataclysmic variables UX UMa and V1101 Aql with data from my observatory combined with data from others around the world.

  12. Revealing the classes of ionospheric disturbances on the basis of multiyear data on the critical frequency of the F2 layer

    NASA Astrophysics Data System (ADS)

    Barkhatov, N. A.; Barkhatova, O. M.

    2012-07-01

    The bases of the classification method of ionospheric disturbances caused by solar-geomagnetic activity on the basis of the critical frequency of the F2 layer are developed. Data for the total solar activity cycle from 1975 to 1986 were used for studying variations in the critical frequency of the ionospheric F2 layer. The critical frequency was measured at the Moscow ionospheric observatory (55°45'N, 37°37'E) at an interval of 1 h. The gaps in the critical frequency values were filled in by the cubic interpolation method. The solar activity level was estimated using the F10.7 index. The geomagnetic disturbance was determined using the Kp · 10, Dst, and AE indices. According to the developed classification, an index of ionospheric activity is introduced. An analysis of the obtained values of the index for years of solar activity minimum and maximum shows that an increase in the absolute values of the index as a rule occurs at an increase in global geomagnetic and/or auroral disturbances. This fact indicates the sufficient information content of the developed index for characterizing ionospheric activity in any season. Moreover, using the sign of the index, one can form an opinion regarding an increase or decrease in the concentration of the ionospheric F2 layer, because the values of the considered index correspond to real oscillations in the critical frequency of the midlatitude ionosphere.

  13. Response of Ionosphere to the Tropospheric disturbances

    NASA Astrophysics Data System (ADS)

    Maurya, A. K.; Dube, A.; Singh, R.; Cohen, M.

    2015-12-01

    The aim of the present work is to find out response of the ionosphere to the various cases of tropical cyclones. The main process involved is suggested through Atmospheric Gravity waves (AGWs) originating from strong convective systems, propagating upward upto the ionospheric heights and perturbing ionospheric parameters (Bishop et al., 2006). We have used ground and satellite data to extract cyclone induced perturbations at different ionospheric heights along with the various parameters of AGWs during cyclones and associated thunderstorm. The initial results suggest that there is increase in total electron content of the ionosphere with wave like signatures in ionosphere. The satellite observation in optical band shows presence of concentric gravity wave pattern associated with troposphere disturbances with horizontal wavelength of ~50-200km and periods ranging from hours to days. The ground based Very Low Frequency (VLF) measurement shows fluctuations in VLF navigational transmitter signal passing over the region of disturbance. The lightning data from GLD360 lightning network shows intense activity associated with cyclones and increase in lightning peak current and energy during main phase of cyclones which seems to be sufficient enough to derive ionospheric disturbances in the ionosphere. This multi-instrument analysis provide detail information of the three dimensional structure of cyclone and their effect at different altitudes of the ionosphere in the Indian subcontinent.

  14. Ionospheric limitations to time transfer by satellite

    NASA Technical Reports Server (NTRS)

    Knowles, S. H.

    1983-01-01

    The ionosphere can contribute appreciable group delay and phase change to radio signals traversing it; this can constitute a fundamental limitation to the accuracy of time and frequency measurements using satellites. Because of the dispersive nature of the ionosphere, the amount of delay is strongly frequency-dependent. Ionospheric compensation is necessary for the most precise time transfer and frequency measurements, with a group delay accuracy better than 10 nanoseconds. A priori modeling is not accurate to better than 25%. The dual-frequency compensation method holds promise, but has not been rigorously experimentally tested. Irregularities in the ionosphere must be included in the compensation process.

  15. International Reference Ionosphere - Status 2004

    NASA Astrophysics Data System (ADS)

    Bilitza, D.; Reinisch, B.; Triskova, L.; Friedrich, M.

    The International Reference Ionosphere (IRI) is the standard for ionospheric densities and temperatures as recommended by the International Union of Radio Science (URSI) and the Committee on Space Research (COSPAR). A COSPAR/URSI Working Group is in charge of developing and improving the model. It currently consists of 43 members who work on different aspects of the modeling effort. By charter IRI is an empirical model that attempts to represent the combined ionospheric database of ground and space observations as accurately as possible. IRI provides monthly averages of the electron density, total electron content, electron temperature, ion temperature, ion composition (O+, H+, He+, N+, O2+, NO+, Cluster+) and vertical ion drift (at the equator). This paper reports about the most recent activities of the IRI Working Group and about the most recent updates of the IRI model. We review the presentations, discussions, and results of the 2003 IRI Workshop held in Grahamstown, South Africa. Special emphasis will be given to the improvements that are of importance for the IRI model now being proposed as ISO standard

  16. Mechanisms of Ionospheric Mass Escape

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Khazanov, G. V.

    2010-01-01

    The dependence of ionospheric O+ escape flux on electromagnetic energy flux and electron precipitation into the ionosphere is derived for a hypothetical ambipolar pick-up process, powered the relative motion of plasmas and neutral upper atmosphere, and by electron precipitation, at heights where the ions are magnetized but influenced by photo-ionization, collisions with gas atoms, ambipolar and centrifugal acceleration. Ion pick-up by the convection electric field produces "ring-beam" or toroidal velocity distributions, as inferred from direct plasma measurements, from observations of the associated waves, and from the spectra of incoherent radar echoes. Ring-beams are unstable to plasma wave growth, resulting in rapid relaxation via transverse velocity diffusion, into transversely accelerated ion populations. Ion escape is substantially facilitated by the ambipolar potential, but is only weakly affected by centrifugal acceleration. If, as cited simulations suggest, ion ring beams relax into non-thermal velocity distributions with characteristic speed equal to the local ion-neutral flow speed, a generalized "Jeans escape" calculation shows that the escape flux of ionospheric O+ increases with Poynting flux and with precipitating electron density in rough agreement with observations.

  17. NASA Airborne Lidar July 1991

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar July 1991 Data from the 1991 NASA Langley Airborne Lidar flights following the eruption of Pinatubo in July ... and Osborn [1992a, 1992b]. Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  18. NASA Airborne Lidar May 1992

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar May 1992 An airborne Nd:YAG (532 nm) lidar was operated by the NASA Langley Research Center about a year following the June 1991 eruption of ... Osborn [1992a, 1992b].  Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  19. Ancient "Observatories" - A Relevant Concept?

    NASA Astrophysics Data System (ADS)

    Belmonte, Juan Antonio

    It is quite common, when reading popular books on astronomy, to see a place referred to as "the oldest observatory in the world". In addition, numerous books on archaeoastronomy, of various levels of quality, frequently refer to the existence of "prehistoric" or "ancient" observatories when describing or citing monuments that were certainly not built with the primary purpose of observing the skies. Internet sources are also guilty of this practice. In this chapter, the different meanings of the word observatory will be analyzed, looking at how their significances can be easily confused or even interchanged. The proclaimed "ancient observatories" are a typical result of this situation. Finally, the relevance of the concept of the ancient observatory will be evaluated.

  20. Ionospheric plasma deterioration in the area of enhanced seismic activity as compared to antipodal sites far from seismicity

    NASA Astrophysics Data System (ADS)

    Gulyaeva, Tamara; Arikan, Feza; Poustovalova, Ljubov; Stanislawska, Iwona

    2016-07-01

    The early magnetogram records from two nearly antipodal sites at Greenwich and Melbourne corresponding to the activity level at the invariant magnetic latitude of 50 deg give a long series of geomagnetic aa indices since 1868. The aa index derived from magnetic perturbation values at only two observatories (as distinct from the planetary ap index) experiences larger extreme values if either input site is well situated to the overhead ionospheric and/or field aligned current systems producing the magnetic storm effects. Analysis of the earthquakes catalogues since 1914 has shown the area of the peak global earthquake occurrence in the Pacific Ocean southwards from the magnetic equator, and, in particular, at Australia. In the present study the ionospheric critical frequency, foF2, is analyzed from the ionosonde measurements at the nearby observatories, Canberra and Slough (Chilton), and Moscow (control site) since 1944 to 2015. The daily-hourly-annual percentage occurrence of positive ionospheric W index (pW+) and negative index (pW-) is determined. It is found that the ionospheric plasma depletion pW- of the instant foF2 as compared to the monthly median is well correlated to the aa index at all three sites but the positive storm signatures show drastic difference at Canberra (no correlation of pW+ with aa index) as compared to two other sites where the high correlation is found of the ionospheric plasma density enhancement with the geomagnetic activity. A possible suppression of the enhanced ionospheric variability over the region of intense seismicity is discussed in the paper. This study is supported by TUBITAK EEEAG 115E915.

  1. Relating OGO-5 H+ Plasmapause Transitions to Mid-Latitude Topside-Ionospheric Signatures

    NASA Astrophysics Data System (ADS)

    Truhlik, V.; Benson, R. F.; Bilitza, D.; Grebowsky, J. M.; Wang, Y.

    2009-12-01

    Plasmapause transitions, as seen in the H+ and He+ density gradients measured by the Orbiting Geophysical Observatory 5 (OGO 5) ion spectrometer [Sharp, IEE Trans. in Geosci. Elect., 1969], have been investigated in an attempt to relate them to their topside ionospheric signatures as seen in the Alouette-1 & 2 and ISIS-1 data. The satellite data were obtained from the National Space Science Data Center (NSSDC). A search of the OGO-5 data revealed 54 sharp plasmapause crossings as evaluated from the H+ density. The ionospheric footprints (at 1400 km altitude) of the magnetic-field lines through the locations of these plasmapause crossings were then used to search for topside ionospheric electron-density profiles from the NSSDC. No profiles corresponding to these projections were identified. A similar search of the topside-sounder 35-mm ionogram-film database, however, identified 17 cases of candidate "conjunctions" involving Alouette1 & 2 and ISIS 1. We will present samples of the plasmapause OGO-5 ion transitions and the related topside ionospheric signatures and discuss the observations in relation to the recent similar study based on Explorer-45 and ISIS-2 data [Grebowsky et al., JASTP, 2009].

  2. Relating OGO-5 H(+) Plasmapause Transitions to Mid-Latitude Topside-Ionospheric Signatures

    NASA Technical Reports Server (NTRS)

    Truhlik, Vladimir; Benson, Robert F.; Bilitza, Dieter; Grebowsky, Joseph M.; Wang, Yongli

    2009-01-01

    Plasmapause transitions, as seen in the H + and He+ density gradients measured by the Orbiting Geophysical Observatory 5 (OGO 5) ion spectrometer [Sharp, IEE Trans. in Geosci. Elect., 1969], have been investigated in an attempt to relate them to their topside ionospheric signatures as seen in the Alouette-1 & 2 and ISIS-1 data. The satellite data were obtained from the National Space Science Data Center (NSSDC). A search of the OGO-5 data revealed 54 sharp plasmapause crossings as evaluated from the H+ density. The ionospheric footprints (at 1400 km altitude) of the magnetic-field lines through the locations of these plasmapause crossings were then used to search for topside ionospheric electron-density profiles from the NSSDC. No profiles corresponding to these projections were identified. A similar search of the topside-sounder 35-mm ionogram-film database, however, identified 17 cases of candidate "conjunctions" involving Alouette l & 2 and ISIS 1. We will present samples of the plasmapause OGO-5 ion transitions and the related topside ionospheric signatures and discuss the observations in relation to the recent similar study based on Explorer-45 and ISIS-2 data [Grebowsky et al., JASTP, 2009].

  3. Use of Sudden Ionospheric Disturbance Monitors to Detect Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Campagna, A.; Amador, J.; Marchese, A. K.; Espinosa, M.

    2015-12-01

    The purpose of this research is to study the effect of Earth directed coronal mass ejections (CMEs) on the ionosphere in 2011, and to see if sudden ionospheric disturbance (SID) monitors could be used to predict whether a CME was geoeffective. A CME is a cloud of highly energized particles ejected from the Sun. It is hypothesized that a strong CME will affect the ionosphere, and this might be observed in certain data sets. Data was taken from two SID monitors in Vienna receiving transmissions from Norway and France from February through July, 2011. This data was then analyzed relative to the kinetic energy of Earth directed CMEs that occurred during the same time period. The Earth directed CME data was taken from the Large Angle and Spectrometric Coronagraph (LASCO) device on NASA's Solar and Heliospheric Observatory (SOHO). A correlation was found between CME kinetic energy and SID energy, with the maximum correlation at a 6 day lag of the SID data. The 6 day delay accounts for the travel time for the CME to reach Earth. Though the impact of the CME on the ionosphere was observed retrospectively, the research indicates that CMEs may be identified using SID monitors alone.

  4. Detection of ionospheric Alfvén resonator signatures in the equatorial ionosphere

    NASA Astrophysics Data System (ADS)

    Simões, Fernando; Klenzing, Jeffrey; Ivanov, Stoyan; Pfaff, Robert; Freudenreich, Henry; Bilitza, Dieter; Rowland, Douglas; Bromund, Kenneth; Liebrecht, Maria Carmen; Martin, Steven; Schuck, Peter; Uribe, Paulo; Yokoyama, Tatsuhiro

    2012-11-01

    The ionosphere response resulting from minimum solar activity during cycle 23/24 was unusual and offered unique opportunities for investigating space weather in the near-Earth environment. We report ultra low frequency electric field signatures related to the ionospheric Alfvén resonator detected by the Communications/Navigation Outage Forecasting System (C/NOFS) satellite in the equatorial region. These signatures are used to constrain ionospheric empirical models and offer a new approach for monitoring ionosphere dynamics and space weather phenomena, namely aeronomy processes, Alfvén wave propagation, and troposphere-ionosphere-magnetosphere coupling mechanisms.

  5. Airborne Fraunhofer Line Discriminator

    NASA Technical Reports Server (NTRS)

    Gabriel, F. C.; Markle, D. A.

    1969-01-01

    Airborne Fraunhofer Line Discriminator enables prospecting for fluorescent materials, hydrography with fluorescent dyes, and plant studies based on fluorescence of chlorophyll. Optical unit design is the coincidence of Fraunhofer lines in the solar spectrum occurring at the characteristic wavelengths of some fluorescent materials.

  6. Recognizing Airborne Hazards.

    ERIC Educational Resources Information Center

    Schneider, Christian M.

    1990-01-01

    The heating, ventilating, and air conditioning (HVAC) systems in older buildings often do not adequately handle air-borne contaminants. Outlines a three-stage Indoor Air Quality (IAQ) assessment and describes a case in point at a Pittsburgh, Pennsylvania, school. (MLF)

  7. Airborne asbestos in buildings.

    PubMed

    Lee, R J; Van Orden, D R

    2008-03-01

    The concentration of airborne asbestos in buildings nationwide is reported in this study. A total of 3978 indoor samples from 752 buildings, representing nearly 32 man-years of sampling, have been analyzed by transmission electron microscopy. The buildings that were surveyed were the subject of litigation related to suits alleging the general building occupants were exposed to a potential health hazard as a result the presence of asbestos-containing materials (ACM). The average concentration of all airborne asbestos structures was 0.01structures/ml (s/ml) and the average concentration of airborne asbestos > or = 5microm long was 0.00012fibers/ml (f/ml). For all samples, 99.9% of the samples were <0.01 f/ml for fibers longer than 5microm; no building averaged above 0.004f/ml for fibers longer than 5microm. No asbestos was detected in 27% of the buildings and in 90% of the buildings no asbestos was detected that would have been seen optically (> or = 5microm long and > or = 0.25microm wide). Background outdoor concentrations have been reported at 0.0003f/ml > or = 5microm. These results indicate that in-place ACM does not result in elevated airborne asbestos in building atmospheres approaching regulatory levels and that it does not result in a significantly increased risk to building occupants.

  8. The Sudbury Neutrino Observatory

    NASA Astrophysics Data System (ADS)

    Ewan, G. T.

    1992-04-01

    The Sudbury Neutrino Observatory (SNO) detector is a 1000 ton heavy water (D2O) Cherenkov detector designed to study neutrinos from the sun and other astrophysical sources. The use of heavy water allows both electron neutrinos and all other types of neutrinos to be observed by three complementary reactions. The detector will be sensitive to the electron neutrino flux and energy spectrum shape and to the total neutrino flux irrespective of neutrino type. These measurements will provide information on both vacuum neutrino oscillations and matter-enhanced oscillations, the MSW effect. In the event of a supernova it will be very sensitive to muon and tau neutrinos as well as the electron neutrinos emitted in the initial burst, enabling sensitive mass measurements as well as providing details of the physics of stellar collapse. On behalf of the Sudbury Neutrino Observatory (SNO) Collaboration : H.C . Evans, G.T . Ewan, H.W. Lee, J .R . Leslie, J .D. MacArthur, H .-B . Mak, A.B . McDonald, W. McLatchie, B.C . Robertson, B. Sur, P. Skensved (Queen's University) ; C.K . Hargrove, H. Mes, W.F. Davidson, D. Sinclair, 1 . Blevis, M. Shatkay (Centre for Research in Particle Physics) ; E.D. Earle, G.M. Milton, E. Bonvin, (Chalk River Laboratories); J .J . Simpson, P. Jagam, J . Law, J .-X . Wang (University of Guelph); E.D . Hallman, R.U. Haq (Laurentian University); A.L. Carter, D. Kessler, B.R . Hollebone (Carleton University); R. Schubank . C.E . Waltha m (University of British Columbia); R.T. Kouzes, M.M. Lowry, R.M. Key (Princeton University); E.W. Beier, W. Frati, M. Newcomer, R. Van Berg (University of Penn-sylvania), T.J . Bowles, P.J . Doe, S.R . Elliott, M.M. Fowler, R.G.H. Robertson, D.J . Vieira, J .B . Wilhelmy, J .F. Wilker-son, J .M. Wouters (Los Alamos National Laboratory) ; E. Norman, K. Lesko, A. Smith, R. Fulton, R. Stokstad (Lawrence Berkeley Laboratory), N.W. Tanner, N. JCIILY, P. Trent, J . Barton, D.L . Wark (University of Oxford).

  9. International Symposium on Airborne Geophysics

    NASA Astrophysics Data System (ADS)

    Mogi, Toru; Ito, Hisatoshi; Kaieda, Hideshi; Kusunoki, Kenichiro; Saltus, Richard W.; Fitterman, David V.; Okuma, Shigeo; Nakatsuka, Tadashi

    2006-05-01

    Airborne geophysics can be defined as the measurement of Earth properties from sensors in the sky. The airborne measurement platform is usually a traditional fixed-wing airplane or helicopter, but could also include lighter-than-air craft, unmanned drones, or other specialty craft. The earliest history of airborne geophysics includes kite and hot-air balloon experiments. However, modern airborne geophysics dates from the mid-1940s when military submarine-hunting magnetometers were first used to map variations in the Earth's magnetic field. The current gamut of airborne geophysical techniques spans a broad range, including potential fields (both gravity and magnetics), electromagnetics (EM), radiometrics, spectral imaging, and thermal imaging.

  10. A comprehensive sounding of the ionospheric HF radio link from Antarctica to Spain

    NASA Astrophysics Data System (ADS)

    Ads, A. G.; Bergadã, P.; Vilella, C.; Regué, J. R.; Pijoan, J. L.; Bardají, R.; Mauricio, J.

    2013-01-01

    Since 2003, our group has been investigating the performance of different transmission techniques for low-power low-interference High Frequency (HF) ionospheric communication systems. Specifically, we have focused on the link between the Spanish Antarctic Station (SAS) Juan Carlos I in Livingston Island and Ebro Observatory (OE) in Spain, in order to transmit the data gathered from some geomagnetic sensors. These transmission techniques require a valuable knowledge of the channel behavior, thus a comprehensive narrowband and wideband sounding of the ionospheric channel is needed. Some significant improvements both in the system and in the signal processing have been done to achieve this goal. The analysis time and the frequency band have been extended to 24 hours per day and to the whole HF band (2-30 MHz). Moreover, new measurements of the absolute propagation time and the Doppler frequency shift are introduced. In this paper, the sounding results obtained using the new system are presented.

  11. HF produced ionospheric electron density irregularities diagnosed by UHF radio star scintillations

    NASA Technical Reports Server (NTRS)

    Frey, A.; Gordon, W. E.

    1982-01-01

    Three observations of radio star intensity fluctuations at UHF are reported for HF ionospheric modification experiments carried out at the Arecibo Observatory. Two observations at 430 MHz and one at 1400 MHz suggest that the the thin phase screen theory is a good approximation to the observed power spectra. It is noted, however, that the theory has to be extended to include antenna filtering. This type of filtering is important for UHF radio star scintillations since the antenna usually has a narrow beamwidth. HF power densities of less than 37 microwatts/sq m incident on the ionosphere give rise to electron density irregularities larger than 13% of the ambient density (at 260 km) having scale sizes of approximately 510 m perpendicular to the geomagnetic field. The irregularities are found to form within 20-25 s after the HF power is turned on. The drift velocities of the irregularities can be estimated from the observed power spectra.

  12. Generation of a severe convective ionospheric storm under stable Rayleigh-Taylor conditions: triggering by meteors?

    NASA Astrophysics Data System (ADS)

    Kelley, M. C.; Ilma, R. R.

    2016-02-01

    Here we report on four events detected using the Jicamarca Radio Observatory (JRO) over an 18-year period, in which huge convective ionospheric storms (CISs) occur in a stable ionosphere. We argue that these rare events could be initiated by meteor-induced electric fields. The meteor-induced electric fields map to the bottomside of the F region, causing radar echoes and a localized CIS. If and when a localized disturbance reaches 500 km, we argue that it becomes two-dimensionally turbulent and cascades structure to both large and small scales. This leads to long-lasting structure and, almost certainly, to scintillations over a huge range of latitudes some ±15° wide and to 3 m irregularities, which backscatter the VHF radar waves. These structures located at high altitudes are supported by vortices shed by the upwelling bubble in a vortex street.

  13. High Power Radio Wave Interactions within the D-Region Ionosphere

    NASA Astrophysics Data System (ADS)

    Moore, R. C.

    2014-12-01

    This paper highlights the best results obtained during D-region modification experiments performed by the University of Florida at the High-frequency Active Auroral Research Program (HAARP) observatory between 2007 and 2014. Over this period, we have seen a tremendous improvement in ELF/VLF wave generation efficiency. We have identified methods to characterize ambient and modified ionospheric properties and to discern and quantify specific types of interactions. We have demonstrated several important implications of HF cross-modulation effects, including "Doppler Spoofing" on HF radio waves. Throughout this talk, observations are compared with the predictions of an ionospheric HF heating model to provide context and guidance for future D-region modification experiments.

  14. Response of the auroral lower ionosphere to solar flares in March 2012 according to ELF observations

    NASA Astrophysics Data System (ADS)

    Lebed', O. M.; Fedorenko, Yu. V.; Larchenko, A. V.; Pil'gaev, S. V.

    2015-11-01

    The response of the lower ionosphere to the solar flares that occurred in March 2012 is considered. Measurements of the propagation velocity and wave impedance of ELF electromagnetic pulses (atmospherics) performed at Lovozero and Barentsburg high-latitude observatories were used to estimate this response. It was shown that the daily average propagation velocity of atmospherics decreased by 20-30 thousand km/s under disturbed heliogeophysical conditions as compared to the velocity measured under quiet conditions. This is related to a decrease in the effective waveguide height that results from the change in the ionospheric conductivity profile during a solar flare. It was detected that pronounced bursts of wave impedance, the maximums of which exceed the impedance average value by a factor of more than 2, are observed during strong heliogeophysical disturbances. This fact cannot be explained in the scope of a spherically layered model; consequently, such deviations indicate an increase in the D-layer conductivity inhomogeneities.

  15. Klimovskaya: A new geomagnetic observatory

    NASA Astrophysics Data System (ADS)

    Soloviev, A. A.; Sidorov, R. V.; Krasnoperov, R. I.; Grudnev, A. A.; Khokhlov, A. V.

    2016-05-01

    In 2011 Geophysical Center RAS (GC RAS) began to deploy the Klimovskaya geomagnetic observatory in the south of Arkhangelsk region on the territory of the Institute of Physiology of Natural Adaptations, Ural Branch, Russian Academy of Sciences (IPNA UB RAS). The construction works followed the complex of preparatory measures taken in order to confirm that the observatory can be constructed on this territory and to select the optimal configuration of observatory structures. The observatory equipping stages are described in detail, the technological and design solutions are described, and the first results of the registered data quality control are presented. It has been concluded that Klimovskaya observatory can be included in INTERMAGNET network. The observatory can be used to monitor and estimate geomagnetic activity, because it is located at high latitudes and provides data in a timely manner to the scientific community via the web-site of the Russian-Ukrainian Geomagnetic Data Center. The role of ground observatories such as Klimovskaya remains critical for long-term observations of secular variation and for complex monitoring of the geomagnetic field in combination with low-orbiting satellite data.

  16. Study of the Pre-Reversal Enhancement at the Jicamarca Radio Observatory using the ASPEN-TIMEGCM

    NASA Astrophysics Data System (ADS)

    Makela, J. J.; Crowley, G.; Kelley, M. C.; Nicolls, M. J.; Kudeki, E.; Chau, J. L.

    2003-12-01

    The Advanced Space Environment Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model (ASPEN-TIMEGCM) has been run to simulate the global ionosphere for three days in April 2002 and five days in June 2002. The April period was a time of quiet geomagnetic activity preceding an intense storm while the June period was a time of quiet to moderate activity. These periods were chosen as data from the Jicamarca Radio Observatory were available. Here, we concentrate on the eastward electric field (vertical ion drift) at the location of Jicamarca, as this is one of the most important parameters in setting up the low-latitude ionosphere. We find that the model properly captures the variations of the eastward equatorial electric field. In particular, it correctly models the timing and magnitude of the pre-reversal enhancement, both on nights when it is present and those when it is not.

  17. Fourier and Wavelet Based Characterisation of the Ionospheric Response to the Solar Eclipse of August, the 11th, 1999, Measured Through 1-minute Vertical Ionospheric Sounding

    NASA Astrophysics Data System (ADS)

    Sauli, P.; Abry, P.; Boska, J.

    2004-05-01

    The aim of the present work is to study the ionospheric response induced by the solar eclipse of August, the 11th, 1999. We provide Fourier and wavelet based characterisations of the propagation of the acoustic-gravity waves induced by the solar eclipse. The analysed data consist of profiles of electron concentration. They are derived from 1-minute vertical incidence ionospheric sounding measurements, performed at the Pruhonice observatory (Czech republic, 49.9N, 14.5E). The chosen 1-minute high sampling rate aims at enabling us to specifically see modes below acoustic cut-off period. The August period was characterized by Solar Flux F10.7 = 128, steady solar wind, quiet magnetospheric conditions, a low geomagnetic activity (Dst index varies from -10 nT to -20 nT, Σ Kp index reached value of 12+). The eclipse was notably exceptional in uniform solar disk. These conditions and fact that the culmination of the solar eclipse over central Europe occurred at local noon are such that the observed ionospheric response is mainly that of the solar eclipse. We provide a full characterization of the propagation of the waves in terms of times of occurrence, group and phase velocities, propagation direction, characteristic period and lifetime of the particular wave structure. However, ionospheric vertical sounding technique enables us to deal with vertical components of each characteristic. Parameters are estimated combining Fourier and wavelet analysis. Our conclusions confirm earlier theoretical and experimental findings, reported in [Altadill et al., 2001; Farges et al., 2001; Muller-Wodarg et al.,1998] regarding the generation and propagation of gravity waves and provide complementary characterisation using wavelet approaches. We also report a new evidence for the generation and propagation of acoustic waves induced by the solar eclipse through the ionospheric F region. Up to our knowledge, this is the first time that acoustic waves can be demonstrated based on ionospheric

  18. The Solar Dynamics Observatory

    NASA Technical Reports Server (NTRS)

    Pesnell, William D.

    2008-01-01

    The Solar Dynamics Observatory (SDO) is the first Space Weather Mission in NASA's Living With a Star Program. SDO's main goal is to understand, driving towards a predictive capability, those solar variations that influence life on Earth and humanity's technological systems. The past decade has seen an increasing emphasis on understanding the entire Sun, from the nuclear reactions at the core to the development and loss of magnetic loops in the corona. SDO's three science investigations (HMI, AIA, and EVE) will determine how the Sun's magnetic field is generated and structured, how this stored magnetic energy is released into the heliosphere and geospace as the solar wind, energetic particles, and variations in the solar irradiance. SDO will return full-disk Dopplergrams, full-disk vector magnetograms, full-disk images at nine EIUV wavelengths, and EUV spectral irradiances, all taken at a rapid cadence. This means you can 'observe the database' to study events, but we can also move forward in producing quantitative models of what the Sun is doing today. SDO is scheduled to launch in 2008 on an Atlas V rocket from the Kennedy Space Center, Cape Canaveral, Florida. The satellite will fly in a 28 degree inclined geosynchronous orbit about the longitude of New Mexico, where a dedicated Ka-band ground station will receive the 150 Mbps data flow. How SDO data will transform the study of the Sun and its affect on Space Weather studies will be discussed.

  19. Photoreactivation in Airborne Mycobacterium parafortuitum

    PubMed Central

    Peccia, Jordan; Hernandez, Mark

    2001-01-01

    Photoreactivation was observed in airborne Mycobacterium parafortuitum exposed concurrently to UV radiation (254 nm) and visible light. Photoreactivation rates of airborne cells increased with increasing relative humidity (RH) and decreased with increasing UV dose. Under a constant UV dose with visible light absent, the UV inactivation rate of airborne M. parafortuitum cells decreased by a factor of 4 as RH increased from 40 to 95%; however, under identical conditions with visible light present, the UV inactivation rate of airborne cells decreased only by a factor of 2. When irradiated in the absence of visible light, cellular cyclobutane thymine dimer content of UV-irradiated airborne M. parafortuitum and Serratia marcescens increased in response to RH increases. Results suggest that, unlike in waterborne bacteria, cyclobutane thymine dimers are not the most significant form of UV-induced DNA damage incurred by airborne bacteria and that the distribution of DNA photoproducts incorporated into UV-irradiated airborne cells is a function of RH. PMID:11526027

  20. Performance of ROB's near real-time ionospheric product during normal and disturbed space weather periods.

    NASA Astrophysics Data System (ADS)

    Bergeot, Nicolas; Chevalier, Jean-Marie; Bruyninx, Carine

    2015-04-01

    Several agencies are routinely monitoring the vertical Total Electron Content (vTEC) using GNSS data. Derived maps are available with different latencies, area extents, and grid/time resolutions. However, no high-resolution maps are publically available over Europe in near real-time. In this frame, the Royal Observatory of Belgium (ROB) developed the ROB-IONO software which takes advantage of the dense EUREF Permanent GNSS Network (EPN) to monitor the ionosphere. The main ROB products consist of ionospheric vTEC maps over Europe and their variability estimated in near real-time every 15 min on 0.5° x 0.5° grids using GPS observations. The maps are available online with a latency of ~3 min in the IONEX format at ftp://gnss.oma.be and as interactive web pages at www.gnss.be. During normal ionospheric activity, the ROB-TEC maps show a good agreement with widely used post-processed global products from IGS, CODE and ESA, with mean differences of 1.3 ± 0.9, 0.6 ± 0.7 and 0.4 ± 1.6 TECu respectively for the period 2012 to mid-2013. For a disturbed period, such as the 2003 Halloween ionospheric storm, the mean differences with IGS, CODE and ESA maps are respectively 0.9 ± 2.2, 0.1 ± 2.0 and 0.6 ± 6.8 TECu, with maximum differences (>38 TECu) occurring during the major phase of the storm. These differences are due to the lower resolution of global products in time and space compared to the ROB-TEC maps. A description of two recent events, on March 17, 2013 and February 27, 2014 highlights the capability of the method adopted to detect in near real-time abnormal ionospheric behaviour over Europe. The potential of the variability maps as an indicator of rapid ionospheric variations during the 15 min of observations is also highlighted. More than 30 ionospheric events associated with Space weather were detected during the period 2012-2014. The ionospheric perturbations are associated with Coronal Mass Ejections (CMEs, ~70% of the time), active geomagnetic conditions

  1. Snowstorm at the geomagnetic observatory

    NASA Astrophysics Data System (ADS)

    Čop, R.

    2015-08-01

    The Sinji Vrh Geomagnetic Observatory (hereinafter the Observatory) is situated on Gora above Ajdovščina, a highland karst plateau, in the southwestern part of Slovenia. The Observatory operates in exceptional geological and meteorological conditions due to its location. The very first measurements at the time of initial tests showed that weather fronts induce changes in the local magnetic field. The first measurements intended to determine the value of this influence were carried out at the end of summer 2011. In 2013 the first such measurements were carried out in January. This article presents the results of these measurements, showing how the snowstorm induced changes in Earth's magnetic field.

  2. Boyden Observatory, then and now

    NASA Astrophysics Data System (ADS)

    Van Heerden, H. J.

    2008-08-01

    In this article the history of Boyden Observatory, 'the first truly international observatory', from its establishment in 1889 to the present will be discussed. There will be looked at locations, personnel, research done and discoveries made. The discussion will also include sections on the instruments used during that time, with specific emphasis on the 60-inch Boyden Rockefeller Telescope. Details about the instrument's specifications, upgrades, new equipment and role as research instrument will be examined. A final section will then be devoted to where Boyden Observatory finds itself today and where it wants to position itself in the future, specifically in terms of research and education.

  3. OSO-6 Orbiting Solar Observatory

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The description, development history, test history, and orbital performance analysis of the OSO-6 Orbiting Solar Observatory are presented. The OSO-6 Orbiting Solar Observatory was the sixth flight model of a series of scientific spacecraft designed to provide a stable platform for experiments engaged in the collection of solar and celestial radiation data. The design objective was 180 days of orbital operation. The OSO-6 has telemetered an enormous amount of very useful experiment and housekeeping data to GSFC ground stations. Observatory operation during the two-year reporting period was very successful except for some experiment instrument problems.

  4. Investigations of the ionosphere by space techniques

    NASA Technical Reports Server (NTRS)

    Bowhill, S. A.

    1974-01-01

    Much of the impetus to ionosphere research since the International Geophysical Year has come from new types of measurement using space vehicles. The key developments are outlined, together with the contributions that they have made to the understanding of the ionosphere.

  5. Using the ionospheric response to the solar eclipse on 20 March 2015 to detect spatial structure in the solar corona.

    PubMed

    Scott, C J; Bradford, J; Bell, S A; Wilkinson, J; Barnard, L; Smith, D; Tudor, S

    2016-09-28

    The total solar eclipse that occurred over the Arctic region on 20 March 2015 was seen as a partial eclipse over much of Europe. Observations of this eclipse were used to investigate the high time resolution (1 min) decay and recovery of the Earth's ionospheric E-region above the ionospheric monitoring station in Chilton, UK. At the altitude of this region (100 km), the maximum phase of the eclipse was 88.88% obscuration of the photosphere occurring at 9:29:41.5 UT. In comparison, the ionospheric response revealed a maximum obscuration of 66% (leaving a fraction, Φ, of uneclipsed radiation of 34±4%) occurring at 9:29 UT. The eclipse was re-created using data from the Solar Dynamics Observatory to estimate the fraction of radiation incident on the Earth's atmosphere throughout the eclipse from nine different emission wavelengths in the extreme ultraviolet (EUV) and X-ray spectrum. These emissions, having varying spatial distributions, were each obscured differently during the eclipse. Those wavelengths associated with coronal emissions (94, 211 and 335 Å) most closely reproduced the time varying fraction of unobscured radiation observed in the ionosphere. These results could enable historic ionospheric eclipse measurements to be interpreted in terms of the distribution of EUV and X-ray emissions on the solar disc.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. PMID:27550766

  6. Using the ionospheric response to the solar eclipse on 20 March 2015 to detect spatial structure in the solar corona.

    PubMed

    Scott, C J; Bradford, J; Bell, S A; Wilkinson, J; Barnard, L; Smith, D; Tudor, S

    2016-09-28

    The total solar eclipse that occurred over the Arctic region on 20 March 2015 was seen as a partial eclipse over much of Europe. Observations of this eclipse were used to investigate the high time resolution (1 min) decay and recovery of the Earth's ionospheric E-region above the ionospheric monitoring station in Chilton, UK. At the altitude of this region (100 km), the maximum phase of the eclipse was 88.88% obscuration of the photosphere occurring at 9:29:41.5 UT. In comparison, the ionospheric response revealed a maximum obscuration of 66% (leaving a fraction, Φ, of uneclipsed radiation of 34±4%) occurring at 9:29 UT. The eclipse was re-created using data from the Solar Dynamics Observatory to estimate the fraction of radiation incident on the Earth's atmosphere throughout the eclipse from nine different emission wavelengths in the extreme ultraviolet (EUV) and X-ray spectrum. These emissions, having varying spatial distributions, were each obscured differently during the eclipse. Those wavelengths associated with coronal emissions (94, 211 and 335 Å) most closely reproduced the time varying fraction of unobscured radiation observed in the ionosphere. These results could enable historic ionospheric eclipse measurements to be interpreted in terms of the distribution of EUV and X-ray emissions on the solar disc.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'.

  7. Effects of X-ray flares on the aeronomy of Mars: Simultaneous measurements of ionospheric effects of X-ray flares on Earth and Mars

    NASA Astrophysics Data System (ADS)

    Haider, Syed A.; Machado Santos, Angela; Abdu, Mangalathayil A.; Batista, Inez S.; Shah, Siddhi Y.; Thirupathaiah, P.

    2016-07-01

    MIRI: Validation and Testing Requirements We have studied X-ray aeronomy in the ionospheric E region of Mars during six X-ray flares that occurred on 28 March and 6 April, 2001; 17,18 March and 21 April, 2003 and 19 February, 2005 respectively. These flares were responded by the corresponding electron density profiles of Mars Global Surveyor (MGS). The time series of photoionization rate, photoelectron impact ionization rate, photoelectron flux, ion density, electron density and total Electron Content (TEC) are predicted for each flare day. The estimated production rate, flux and densities are increased by 1-2 orders of magnitude due to effects of these flares in the E region ionosphere of Mars. The normalized estimated TEC are compared with the normalized measured TEC of MGS profiles. At the peak flare time the normalized estimated and normalized measured TEC were enhanced by a factor of 5-10 and 2 respectively. The effects of these flares were also registered in the D region equatorial ionosphere of Earth at Fortaleza observatory. The flares of 6 April, 2001, 17 March and 21 April, 2003 also produced electron density enhancement in the E region ionosphere of Earth at College AK and Cachoeira Paulista observatories. The minimum frequency fmin, recorded in ionogram, increased by 100% (due to D region absorption) while the foE increased by 20%, in the Earth's ionosphere.

  8. Ionospheric modification by rocket effluents. Final report

    SciTech Connect

    Bernhardt, P.A.; Price, K.M.; da Rosa, A.V.

    1980-06-01

    This report describes experimental and theoretical studies related to ionospheric disturbances produced by rocket exhaust vapors. The purpose of our research was to estimate the ionospheric effects of the rocket launches which will be required to place the Satellite Power System (SPS) in operation. During the past year, we have developed computational tools for numerical simulation of ionospheric changes produced by the injection of rocket exhaust vapors. The theoretical work has dealt with (1) the limitations imposed by condensation phenomena in rocket exhaust; (2) complete modeling of the ionospheric depletion process including neutral gas dynamics, plasma physics, chemistry and thermal processes; and (3) the influence of the modified ionosphere on radio wave propagation. We are also reporting on electron content measurements made during the launch of HEAO-C on Sept. 20, 1979. We conclude by suggesting future experiments and areas for future research.

  9. Plasma interactions in the Martian Nightside Ionosphere

    NASA Astrophysics Data System (ADS)

    Andersson, L.; Fowler, C. M.; Ergun, R.; Weber, T. D.; Andrews, D. J.; Morooka, M. W.; Delory, G. T.; Eriksson, A. I.; Mitchell, D. L.; McFadden, J. P.; Connerney, J. E. P.

    2015-12-01

    Based on measurements from a number of missions at Mars the nightside ionosphere is patchy. The new mission MAVEN dedicated to observe the upper atmosphere and the plasma interactions provides the first comprehensive observations of the low altitude nightside ionosphere. Observations show that at density gradients the plasma is unstable and significant wave power, heated/accelerated electrons, and heated ions are co-located. Below 300 km, thermal electrons (>3 eV) are observed at the gradients to low density regions. The nightside ionosphere below 180 km is thought to be maintained by electron impact ionization and therefore these regions with thermal electrons may be the primary energy source for the low altitude ionosphere. Outside of the low density regions the plasma is cold. These observations suggest that the wave heating might be the primary process in the Matrian nightside ionosphere. The characteristics of these regions associated with density gradients will be presented and discussed in this presentation.

  10. Charged particles in Titan's ionosphere

    NASA Astrophysics Data System (ADS)

    Tripathi, Sachchida

    2010-05-01

    Charged particles in Titan's ionosphere Marykutty Michael1, Sachchida Nand Tripathi1,2,3, Pratima Arya1 1Indian Institute of Technology Kanpur 2Oak Ridge Associated Universities 3NASA Goddard Space Flight Center Observations by two instruments onboard the Cassini spacecraft, Ion Neutral Mass Spectrometer (INMS) and CAssini Plasma Spectrometer (CAPS), revealed the existence of heavy hydrocarbon and nitrile species with masses of several thousand atomic mass units at altitudes of 950 - 1400 km in the atmosphere of Titan (Waite et al., 2007; Crary et al., 2009). Though these particles were believed to be molecules, they are most likely aerosols formed by the clumping of smaller molecules (Waite et al., 2009). These particles were estimated to have a density of 10-3 kg m-3 and a size of up to 256 nm. The existence of very heavy ions has also been observed by the CAPS components with a mass by charge ratio of up to 10000 (Coates et al., 2007, 2009; Sittler et al., 2009). The goal of this paper is to find out whether the so called heavy ions (or charged particles) are generated by the charge transfer of ions and electrons to the particles. The charging of these particles has been studied by using the charge balance equations that include positive ions, negative ions, electrons, neutral and charged particles. Information on the most abundant ion clusters are obtained from Vuitton et al., (2009) and Wilson and Atreya, (2004). Mass by charge ratio thus calculated will be compared with those observed by Coates et al. (2007). References: Coates AJ, et al., Discovery of heavy negative ions in Titan's ionosphere, Geophys. Res. Lett., 34:L22103, 2007. Coates AJ, et al., Heavy negative ions in titan's ionosphere: altitude and latitude dependence. Planet. Space Sci., doi:10.1016/j.pss.2009.05.009, 2009. Crary F.J., et al., Heavy ions, temperatures and winds in titan's ionosphere: Combined cassini caps and inms observations. Planet. Space Sci., doi:10.1016/j.pss.2009.09.006, 2009

  11. Contribution of the Ebro Observatory team to the IRI climatological modeling: A Review.

    NASA Astrophysics Data System (ADS)

    Altadill, David; Blanch, Estefania; Miquel Torta, J.

    During the recent years, the Geomagnetism and Aeronomy group of the Ebre Observatory has been working to improve the climatological prediction of some ionospheric key parameters. To do that, we have taken advantage of the increasing number of ionospheric stations providing data and sharing it through the Digital Ionospheric Data Base (DIDB). We have used the Spherical Harmonic analysis as analytical technique for globally modeling those parameters during quiet conditions. Models for bottom-side B0 and B1 parameters of IRI, for density peak height (hmF2) and for equivalent scale height (Hm) have been developed. Each SH model has been parameterized according to the time-space pattern of respectively ionospheric parameter and has been bounded to the solar activity. It has been proved that these empirical models improve, in average, the prediction of B0, B1 and hmF2 by 40%, 20% and 10% respectively with respect to previous IRI versions (hmF2 is improved by more than 30% at high and low latitudes). Due to these good results and to the analytical formulation, IRI has adopted the SH empirical models for B0 and B1 as an option in the current version (IRI 2012) and has proposed the SH model for hmF2 to be included into next releases. The analytical model for Hm could be useful to estimate information for the topside profile formulation.

  12. Ionospheric data assimilation and forecasting during storms

    NASA Astrophysics Data System (ADS)

    Chartier, Alex T.; Matsuo, Tomoko; Anderson, Jeffrey L.; Collins, Nancy; Hoar, Timothy J.; Lu, Gang; Mitchell, Cathryn N.; Coster, Anthea J.; Paxton, Larry J.; Bust, Gary S.

    2016-01-01

    Ionospheric storms can have important effects on radio communications and navigation systems. Storm time ionospheric predictions have the potential to form part of effective mitigation strategies to these problems. Ionospheric storms are caused by strong forcing from the solar wind. Electron density enhancements are driven by penetration electric fields, as well as by thermosphere-ionosphere behavior including Traveling Atmospheric Disturbances and Traveling Ionospheric Disturbances and changes to the neutral composition. This study assesses the effect on 1 h predictions of specifying initial ionospheric and thermospheric conditions using total electron content (TEC) observations under a fixed set of solar and high-latitude drivers. Prediction performance is assessed against TEC observations, incoherent scatter radar, and in situ electron density observations. Corotated TEC data provide a benchmark of forecast accuracy. The primary case study is the storm of 10 September 2005, while the anomalous storm of 21 January 2005 provides a secondary comparison. The study uses an ensemble Kalman filter constructed with the Data Assimilation Research Testbed and the Thermosphere Ionosphere Electrodynamics General Circulation Model. Maps of preprocessed, verticalized GPS TEC are assimilated, while high-latitude specifications from the Assimilative Mapping of Ionospheric Electrodynamics and solar flux observations from the Solar Extreme Ultraviolet Experiment are used to drive the model. The filter adjusts ionospheric and thermospheric parameters, making use of time-evolving covariance estimates. The approach is effective in correcting model biases but does not capture all the behavior of the storms. In particular, a ridge-like enhancement over the continental USA is not predicted, indicating the importance of predicting storm time electric field behavior to the problem of ionospheric forecasting.

  13. The Infrared Space Observatory (ISO)

    NASA Technical Reports Server (NTRS)

    Helou, George; Kessler, Martin F.

    1995-01-01

    ISO, scheduled to launch in 1995, will carry into orbit the most sophisticated infrared observatory of the decade. Overviews of the mission, instrument payload and scientific program are given, along with a comparison of the strengths of ISO and SOFIA.

  14. Haystack Observatory Technology Development Center

    NASA Technical Reports Server (NTRS)

    Beaudoin, Chris; Corey, Brian; Niell, Arthur; Cappallo, Roger; Whitney, Alan

    2013-01-01

    Technology development at MIT Haystack Observatory were focused on four areas in 2012: VGOS developments at GGAO; Digital backend developments and workshop; RFI compatibility at VLBI stations; Mark 6 VLBI data system development.

  15. Islamic Astronomical Instruments and Observatories

    NASA Astrophysics Data System (ADS)

    Heidarzadeh, Tofigh

    This chapter is a brief survey of astronomical instruments being used and developed in Islamic territories from the eighth to the fifteenth centuries as well as a concise account of major observatories and observational programs in this period.

  16. An astronomical observatory for Peru

    NASA Astrophysics Data System (ADS)

    del Mar, Juan Quintanilla; Sicardy, Bruno; Giraldo, Víctor Ayma; Callo, Víctor Raúl Aguilar

    2011-06-01

    Peru and France are to conclude an agreement to provide Peru with an astronomical observatory equipped with a 60-cm diameter telescope. The principal aims of this project are to establish and develop research and teaching in astronomy. Since 2004, a team of researchers from Paris Observatory has been working with the University of Cusco (UNSAAC) on the educational, technical and financial aspects of implementing this venture. During an international astronomy conference in Cusco in July 2009, the foundation stone of the future Peruvian Observatory was laid at the top of Pachatusan Mountain. UNSAAC, represented by its Rector, together with the town of Oropesa and the Cusco regional authority, undertook to make the sum of 300,000€ available to the project. An agreement between Paris Observatory and UNSAAC now enables Peruvian students to study astronomy through online teaching.

  17. Atmospheric waves and the ionosphere.

    NASA Technical Reports Server (NTRS)

    Beer, T.

    1972-01-01

    A review of evidence supporting the existence of atmospheric waves is presented, and a simple, theoretical approach for describing them is shown. Suggestions for gravity wave sources include equatorial and auroral electrojet, auroral and polar substorm heating, atmospheric jet streams, and large oceanic tides. There are reviewed previous studies dealing with the interaction between ionization and atmospheric waves believed to exist at ionospheric heights. These waves include acoustic waves, evanescent waves, and internal atmospheric gravity waves. It is explained that mode analysis, often employed when an increased number of layers is used for a more complete profile, is inapplicable for waves very close to a source.

  18. Convergent instability in the ionosphere

    SciTech Connect

    Ponyatov, A.A.

    1994-04-01

    A linear theory of the convergent instability (CI) of ionospheric plasma associated with the nonuniform nature of its regular motion is examined. The conditions under which CI appears in the E- and F-layers for vertical ion motion caused by various physical factors are analyzed. The possibility of small-scale strongly geomagnetic-field-aligned nonuniformities of electron concentration (l{sub min} {approximately} 10-30 m) is demonstrated. The altitude dependence of collision frequency is shown to play a large role in CI.

  19. Aerosol growth in Titan's ionosphere.

    PubMed

    Lavvas, Panayotis; Yelle, Roger V; Koskinen, Tommi; Bazin, Axel; Vuitton, Véronique; Vigren, Erik; Galand, Marina; Wellbrock, Anne; Coates, Andrew J; Wahlund, Jan-Erik; Crary, Frank J; Snowden, Darci

    2013-02-19

    Photochemically produced aerosols are common among the atmospheres of our solar system and beyond. Observations and models have shown that photochemical aerosols have direct consequences on atmospheric properties as well as important astrobiological ramifications, but the mechanisms involved in their formation remain unclear. Here we show that the formation of aerosols in Titan's upper atmosphere is directly related to ion processes, and we provide a complete interpretation of observed mass spectra by the Cassini instruments from small to large masses. Because all planetary atmospheres possess ionospheres, we anticipate that the mechanisms identified here will be efficient in other environments as well, modulated by the chemical complexity of each atmosphere. PMID:23382231

  20. Saturn: atmosphere, ionosphere, and magnetosphere.

    PubMed

    Gombosi, Tamas I; Ingersoll, Andrew P

    2010-03-19

    The Cassini spacecraft has been in orbit around Saturn since 30 June 2004, yielding a wealth of data about the Saturn system. This review focuses on the atmosphere and magnetosphere and briefly outlines the state of our knowledge after the Cassini prime mission. The mission has addressed a host of fundamental questions: What processes control the physics, chemistry, and dynamics of the atmosphere? Where does the magnetospheric plasma come from? What are the physical processes coupling the ionosphere and magnetosphere? And, what are the rotation rates of Saturn's atmosphere and magnetosphere?

  1. Saturn: atmosphere, ionosphere, and magnetosphere.

    PubMed

    Gombosi, Tamas I; Ingersoll, Andrew P

    2010-03-19

    The Cassini spacecraft has been in orbit around Saturn since 30 June 2004, yielding a wealth of data about the Saturn system. This review focuses on the atmosphere and magnetosphere and briefly outlines the state of our knowledge after the Cassini prime mission. The mission has addressed a host of fundamental questions: What processes control the physics, chemistry, and dynamics of the atmosphere? Where does the magnetospheric plasma come from? What are the physical processes coupling the ionosphere and magnetosphere? And, what are the rotation rates of Saturn's atmosphere and magnetosphere? PMID:20299587

  2. Capabilities and Limitations of Radio Occultation Measurements for Ionosphere Monitoring

    NASA Technical Reports Server (NTRS)

    Hajj, G. A.; Romans, L. J.; Pi, X.; Wang, Chunming

    1999-01-01

    The paper: (1) describes the range of capabilities of GPS radio occultation missions in ionospheric research: (a) ionospheric profiling; (b) ionospheric imaging; (c) ionospheric data assimilation; and (d) measurement of scintillation. (2) Identify strengths and weaknesses of measurements: (a) coverage; (b) resolution; and (c) uniqueness of solution.

  3. Status of the SOFIA Observatory

    NASA Technical Reports Server (NTRS)

    Roellig, Thomas L.

    2015-01-01

    The SOFIA observatory has been in routine science operations since returning in January from a 6 month-long heavy maintenance period for the aircraft and the telescope assembly. These operations include a successful 6 week deployment to the Southern hemisphere. This presentation will provide an update to the current operational status of the SOFIA observatory, concentrating on the improvements and upgrades that have been implemented since the heavy maintenance period.

  4. Precise Point Positioning with Ionosphere Estimation and application of Regional Ionospheric Maps

    NASA Astrophysics Data System (ADS)

    Galera Monico, J. F.; Marques, H. A.; Rocha, G. D. D. C.

    2015-12-01

    The ionosphere is one of most difficult source of errors to be modelled in the GPS positioning, mainly when applying data collected by single frequency receivers. Considering Precise Point Positioning (PPP) with single frequency data the options available include, for example, the use of Klobuchar model or applying Global Ionosphere Maps (GIM). The GIM contains Vertical Electron Content (VTEC) values that are commonly estimated considering a global network with poor covering in certain regions. For this reason Regional Ionosphere Maps (RIM) have been developed considering local GNSS network, for instance, the La Plata Ionospheric Model (LPIM) developed inside the context of SIRGAS (Geocentric Reference System for Americas). The South American RIM are produced with data from nearly 50 GPS ground receivers and considering these maps are generated for each hour with spatial resolution of one degree it is expected to provide better accuracy in GPS positioning for such region. Another possibility to correct for ionosphere effects in the PPP is to apply the ionosphere estimation technique based on Kalman filter. In this case, the ionosphere can be treated as a stochastic process and a good initial guess is necessary what can be obtained from an ionospheric map. In this paper we present the methodology involved with ionosphere estimation by using Kalman filter and also the application of global and regional ionospheric maps in the PPP as first guess. The ionosphere estimation strategy was implemented in the house software called RT_PPP that is capable of accomplishing PPP either for single or dual frequency data. GPS data from Brazilian station near equatorial region were processed and results with regional maps were compared with those by using global maps. Improvements of the order 15% were observed. In case of ionosphere estimation, the estimated coordinates were compared with ionosphere free solution and after PPP convergence the results reached centimeter accuracy.

  5. Sofia Observatory Performance and Characterization

    NASA Technical Reports Server (NTRS)

    Temi, Pasquale; Miller, Walter; Dunham, Edward; McLean, Ian; Wolf, Jurgen; Becklin, Eric; Bida, Tom; Brewster, Rick; Casey, Sean; Collins, Peter; Jakob, Holger; Killebrew, Jana; Lampater, Ulrich; Mandushev, Georgi; Marcum, Pamela; Meyer, Allan; Pfueller, Enrico; Reinacher, Andreas; Roeser, Hans-Peter; Savage, Maureen; Teufel, Stefan; Wiedemann, Manuel

    2012-01-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) has recently concluded a set of engineering flights for Observatory performance evaluation. These in-flight opportunities have been viewed as a first comprehensive assessment of the Observatory's performance and will be used to address the development activity that is planned for 2012, as well as to identify additional Observatory upgrades. A series of 8 SOFIA Characterization And Integration (SCAI) flights have been conducted from June to December 2011. The HIPO science instrument in conjunction with the DSI Super Fast Diagnostic Camera (SFDC) have been used to evaluate pointing stability, including the image motion due to rigid-body and flexible-body telescope modes as well as possible aero-optical image motion. We report on recent improvements in pointing stability by using an Active Mass Damper system installed on Telescope Assembly. Measurements and characterization of the shear layer and cavity seeing, as well as image quality evaluation as a function of wavelength have been performed using the HIPO+FLITECAM Science Instrument configuration (FLIPO). A number of additional tests and measurements have targeted basic Observatory capabilities and requirements including, but not limited to, pointing accuracy, chopper evaluation and imager sensitivity. SCAI activities included in-flight partial Science Instrument commissioning prior to the use of the instruments as measuring engines. This paper reports on the data collected during the SCAI flights and presents current SOFIA Observatory performance and characterization.

  6. [Air-borne disease].

    PubMed

    Lameiro Vilariño, Carmen; del Campo Pérez, Victor M; Alonso Bürger, Susana; Felpeto Nodar, Irene; Guimarey Pérez, Rosa; Pérez Alvarellos, Alberto

    2003-11-01

    Respiratory protection is a factor which worries nursing professionals who take care of patients susceptible of transmitting microorganisms through the air more as every day passes. This type of protection covers the use of surgical or hygienic masks against the transmission of infection by airborne drops to the use of highly effective masks or respirators against the transmission of airborne diseases such as tuberculosis or SARS, a recently discovered disease. The adequate choice of this protective device and its correct use are fundamental in order to have an effective protection for exposed personnel. The authors summarize the main protective respiratory devices used by health workers, their characteristics and degree of effectiveness, as well as the circumstances under which each device is indicated for use. PMID:14705591

  7. Using the Global GPS Network and Other Satellite Data to Monitor Ionospheric Total Electron Content

    NASA Technical Reports Server (NTRS)

    Mannucci, Anthony J.; Wilson, Brian D.; Yuan, Dah-Ning; Lindqwister, Ulf

    1994-01-01

    A globally distributed network of dual-frequency global positioning system (GPS) receivers is the primary source of data used to measure ionospheric total electron content (TEC) on global scales. Maps of TEC useful for calibrating propagation delays, or monitoring the solar-terrestrial environment, can be produced using this continuously operating network. The maps can also form the basis of a TEC calibration service for users around the world. Potential users may include single-frequency satellite altimetry missions, satellite tracking stations, and astronomical observatories.

  8. Early results of the ionospheric experiment of the Apollo-Soyuz Test Project

    NASA Technical Reports Server (NTRS)

    Grossi, M. D.; Gay, R. H.

    1976-01-01

    A description is presented of a spacecraft-to-spacecraft Doppler-tracking experiment which was performed by the Smithsonian Astrophysical Observatory on the occasion of the Apollo-Soyuz Test Project (ASTP). The experiment involved the measurement of the relative velocity between the ASTP docking module and the Apollo command service module by a Doppler-tracking method. The objectives of the ionospheric experiment include the measurement of the time changes of the columnar electron content between the two spacecraft. The obtained data can provide a basis for the determination of the horizontal gradients of electron density at the height of 220 km.

  9. MLS airborne antenna research

    NASA Technical Reports Server (NTRS)

    Yu, C. L.; Burnside, W. D.

    1975-01-01

    The geometrical theory of diffraction was used to analyze the elevation plane pattern of on-aircraft antennas. The radiation patterns for basic elements (infinitesimal dipole, circumferential and axial slot) mounted on fuselage of various aircrafts with or without radome included were calculated and compared well with experimental results. Error phase plots were also presented. The effects of radiation patterns and error phase plots on the polarization selection for the MLS airborne antenna are discussed.

  10. Airborne forest fire research

    NASA Technical Reports Server (NTRS)

    Mattingly, G. S.

    1974-01-01

    The research relating to airborne fire fighting systems is reviewed to provide NASA/Langley Research Center with current information on the use of aircraft in forest fire operations, and to identify research requirements for future operations. A literature survey, interview of forest fire service personnel, analysis and synthesis of data from research reports and independent conclusions, and recommendations for future NASA-LRC programs are included.

  11. Ionospheric Challenges for GNSS Based Augmentation Systems

    NASA Astrophysics Data System (ADS)

    Doherty, P.; Valladares, C. E.

    2007-12-01

    The ionosphere is a highly dynamic physical phenomenon that presents a variable source of error for Global Navigation Satellite System (GNSS) signals and GNSS based operational systems. The Federal Aviation Administration's (FAA) Wide-Area Augmentation System (WAAS) was designed to enhance the GNSS standard positioning service by providing additional accuracy, availability and integrity that is sufficient for use in commercial aviation. It is the first of a number of planned regional Satellite Based Augmentation Systems (SBAS). Other systems in development include the European EGNOS system, the MSAS system in Japan and the GAGAN system in India. In addition, the South American countries are investigating the feasibility of operating an SBAS system in this region. Much of the WAAS ionospheric research and development focused on defining and mitigating ionospheric challenges characteristic of the mid-latitude regions, where the ionosphere is well studied and relatively quiescent. The EGNOS and MSAS systems will primarily operate under a similarly quiescent mid-latitude ionosphere. SBAS system development in South America, India and other low-latitude regions, however, will have to contend with much more extreme conditions. These conditions include strong spatial and temporal gradients, plasma depletions and scintillation. All of these conditions have a potential to limit SBAS performance in the low latitude regions. This presentation will review the effects that the ionosphere has on the mid-latitude WAAS system. It will present the techniques that are used to mitigate ionospheric disturbances induced on the system during severe geomagnetic activity and it will quantify the effect that this activity has on system performance. The presentation will then present data from the South American Low-latitude Ionospheric Sensor Network (LISN) that can be used to infer the ionospheric effects on SBAS performance in the most challenging low-latitude ionospheric environment

  12. Diagnosis of Magnetotail Drivers for Ionospheric Electrodynamics Using Networks of Ground-based Magnetometers

    NASA Astrophysics Data System (ADS)

    Mann, I. R.; Rae, I. J.; Murphy, K.; Milling, D. K.; Russell, C. T.; Angelopoulos, V.

    2009-05-01

    One of the most important problems in solar-terrestrial physics concerns understanding the response of the ionosphere to a variety of physical drivers from the magnetotail. In particular, determining the ionospheric response to magnetotail disturbances such as current disruptions and Earthward-directed bursty bulk flows is key to understanding the causal sequence of events during substorms. We present a series of case studies using data from combined networks of magnetometers in the Canadian sector, including those from CARISMA (www.carisma.ca) and the THEMIS ground-based observatory (GBO) network and supporting arrays, to examine the current response in the ionosphere to substorm expansion phase onset. These analyses highlight the importance of extensive magnetometer coverage in order to correctly identify and characterise the initiation and temporal dynamics of substorm-time ionospheric electrodynamics and current systems. We show how magnetometer data can be used to locate and time the onset of substorms using Pi1 data, and further develop a magnetic disturbance diagnostic which may distinguish between tail drivers. We suggest that the structure of the resulting current systems may enable these processes to be distinguished using a new set of local magnetometer derived disturbance indices. We suggest forms for these new ionospheric disturbance indices, as an extension to the traditional AE, AL and AU indices. We show how these diagnostics can provide important input into substorm studies, especially in partnership with in-situ measurements from the THEMIS probes, and contribute towards resolving the causal sequence of energy release in the substorm cycle.

  13. Recent Advances in Remote Sensing of Natural Hazards-Induced Atmospheric and Ionospheric Perturbations

    NASA Astrophysics Data System (ADS)

    Yang, Y. M.; Komjathy, A.; Meng, X.; Verkhoglyadova, O. P.; Langley, R. B.; Mannucci, A. J.

    2015-12-01

    Traveling ionospheric disturbances (TIDs) induced by acoustic-gravity waves in the neutral atmosphere have significant impact on trans-ionospheric radio waves such as Global Navigation Satellite System (GNSS, including Global Position System (GPS)) measurements. Natural hazards and solid Earth events, such as earthquakes, tsunamis and volcanic eruptions are actual sources that may trigger acoustic and gravity waves resulting in traveling ionospheric disturbances (TIDs) in the upper atmosphere. Trans-ionospheric radio wave measurements sense the total electron content (TEC) along the signal propagation path. In this research, we introduce a novel GPS-based detection and estimation technique for remote sensing of atmospheric wave-induced TIDs including space weather phenomena induced by major natural hazard events, using TEC time series collected from worldwide ground-based dual-frequency GNSS (including GPS) receiver networks. We demonstrate the ability of using ground- and space-based dual-frequency GPS measurements to detect and monitor tsunami wave propagation from the 2011 Tohoku-Oki earthquake and tsunami. Major wave trains with different propagation speeds and wavelengths were identified through analysis of the GPS remote sensing observations. Dominant physical characteristics of atmospheric wave-induced TIDs are found to be associated with specific tsunami propagations and oceanic Rayleigh waves. In this research, we compared GPS-based observations, corresponding model simulations and tsunami wave propagation. Results are shown to lead to a better understanding of the tsunami-induced ionosphere responses. Based on current distribution of Plate Boundary Observatory GPS stations, the results indicate that tsunami-induced TIDs may be detected about 60 minutes prior to tsunamis arriving at the U.S. west coast. It is expected that this GNSS-based technology will become an integral part of future early-warning systems.

  14. Mutagenicity of airborne particles.

    PubMed

    Chrisp, C E; Fisher, G L

    1980-09-01

    The physical and chemical properties of airborne particles are important for the interpretation of their potential biologic significance as genotoxic hazards. For polydisperse particle size distributions, the smallest, most respirable particles are generally the most mutagenic. Particulate collection for testing purposes should be designed to reduce artifact formation and allow condensation of mutagenic compounds. Other critical factors such as UV irradiation, wind direction, chemical reactivity, humidity, sample storage, and temperature of combustion are important. Application of chemical extraction methods and subsequent class fractionation techniques influence the observed mutagenic activity. Particles from urban air, coal fly ash, automobile and diesel exhaust, agricultural burning and welding fumes contain primarily direct-acting mutagens. Cigarette smoke condensate, smoke from charred meat and protein pyrolysates, kerosene soot and cigarette smoke condensates contain primarily mutagens which require metabolic activation. Fractionation coupled with mutagenicity testing indicates that the most potent mutagens are found in the acidic fractions of urban air, coal fly ash, and automobile diesel exhaust, whereas mutagens in rice straw smoke and cigarette smoke condensate are found primarily in the basic fractions. The interaction of the many chemical compounds in complex mixtures from airborne particles is likely to be important in determining mutagenic or comutagenic potentials. Because the mode of exposure is generally frequent and prolonged, the presence of tumor-promoting agents in complex mixtures may be a major factor in evaluation of the carcinogenic potential of airborne particles.

  15. Mammalian airborne allergens.

    PubMed

    Aalberse, Rob C

    2014-01-01

    Historically, horse dandruff was a favorite allergen source material. Today, however, allergic symptoms due to airborne mammalian allergens are mostly a result of indoor exposure, be it at home, at work or even at school. The relevance of mammalian allergens in relation to the allergenic activity of house dust extract is briefly discussed in the historical context of two other proposed sources of house dust allergenic activity: mites and Maillard-type lysine-sugar conjugates. Mammalian proteins involved in allergic reactions to airborne dust are largely found in only 2 protein families: lipocalins and secretoglobins (Fel d 1-like proteins), with a relatively minor contribution of serum albumins, cystatins and latherins. Both the lipocalin and the secretoglobin family are very complex. In some instances this results in a blurred separation between important and less important allergenic family members. The past 50 years have provided us with much detailed information on the genomic organization and protein structure of many of these allergens. However, the complex family relations, combined with the wide range of post-translational enzymatic and non-enzymatic modifications, make a proper qualitative and quantitative description of the important mammalian indoor airborne allergens still a significant proteomic challenge. PMID:24925404

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

    DOEpatents

    Deaton, Juan D.; Schmitt, Michael J.; Jones, Warren F.

    2011-12-13

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

  17. NASA's Earth Venture-1 (EV-1) Airborne Science Investigations

    NASA Technical Reports Server (NTRS)

    Guillory, A.; Denkins, T.; Allen, B. Danette; Braun, Scott A.; Crawford, James H.; Jensen, Eric J.; Miller, Charles E.; Moghaddam, Mahta; Maring, Hal

    2011-01-01

    In 2010, NASA announced the first Earth Venture (EV-1) selections in response to a recommendation made by the National Research Council for low-cost investigations fostering innovation in Earth science. The five EV-1 investigations span the Earth science focus areas of atmosphere, weather, climate, water and energy and, carbon and represent earth science researchers from NASA as well as other government agencies, academia and industry from around the world. The EV-1 missions are: 1) Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS), 2) Airborne Tropical Tropopause Experiment (ATTREX), 3) Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE), 4) Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ), and 5) Hurricane And Severe Storm Sentinel (HS3). The Earth Venture missions are managed out of the Earth System Science Pathfinder (ESSP) Program Office (Allen, et. al. 2010b)

  18. EARLY SCIENCE WITH SOFIA, THE STRATOSPHERIC OBSERVATORY FOR INFRARED ASTRONOMY

    SciTech Connect

    Young, E. T.; Becklin, E. E.; De Buizer, J. M.; Andersson, B.-G.; Casey, S. C.; Helton, L. A.; Marcum, P. M.; Roellig, T. L.; Temi, P.; Herter, T. L.; Guesten, R.; Dunham, E. W.; Backman, D.; Burgdorf, M.; Caroff, L. J.; Erickson, E. F.; Davidson, J. A.; Gehrz, R. D.; Harper, D. A.; Harvey, P. M.; and others

    2012-04-20

    The Stratospheric Observatory For Infrared Astronomy (SOFIA) is an airborne observatory consisting of a specially modified Boeing 747SP with a 2.7 m telescope, flying at altitudes as high as 13.7 km (45,000 ft). Designed to observe at wavelengths from 0.3 {mu}m to 1.6 mm, SOFIA operates above 99.8% of the water vapor that obscures much of the infrared and submillimeter. SOFIA has seven science instruments under development, including an occultation photometer, near-, mid-, and far-infrared cameras, infrared spectrometers, and heterodyne receivers. SOFIA, a joint project between NASA and the German Aerospace Center Deutsches Zentrum fuer Luft und-Raumfahrt, began initial science flights in 2010 December, and has conducted 30 science flights in the subsequent year. During this early science period three instruments have flown: the mid-infrared camera FORCAST, the heterodyne spectrometer GREAT, and the occultation photometer HIPO. This Letter provides an overview of the observatory and its early performance.

  19. The Carl Sagan solar and stellar observatories as remote observatories

    NASA Astrophysics Data System (ADS)

    Saucedo-Morales, J.; Loera-Gonzalez, P.

    In this work we summarize recent efforts made by the University of Sonora, with the goal of expanding the capability for remote operation of the Carl Sagan Solar and Stellar Observatories, as well as the first steps that have been taken in order to achieve autonomous robotic operation in the near future. The solar observatory was established in 2007 on the university campus by our late colleague A. Sánchez-Ibarra. It consists of four solar telescopes mounted on a single equatorial mount. On the other hand, the stellar observatory, which saw the first light on 16 February 2010, is located 21 km away from Hermosillo, Sonora at the site of the School of Agriculture of the University of Sonora. Both observatories can now be remotely controlled, and to some extent are able to operate autonomously. In this paper we discuss how this has been accomplished in terms of the use of software as well as the instruments under control. We also briefly discuss the main scientific and educational objectives, the future plans to improve the control software and to construct an autonomous observatory on a mountain site, as well as the opportunities for collaborations.

  20. Ion Escape from the Ionosphere of Titan

    NASA Technical Reports Server (NTRS)

    Hartle, R.; Sittler, E.; Lipatov, A.

    2008-01-01

    Ions have been observed to flow away from Titan along its induced magnetic tail by the Plasma Science Instrument (PLS) on Voyager 1 and the Cassini Plasma Spectrometer (CAPS) on Cassini. In both cases, the ions have been inferred to be of ionospheric origin. Recent plasma measurements made at another unmagnetized body, Venus, have also observed similar flow in its magnetic tail. Much earlier, the possibility of such flow was inferred when ionospheric measurements made from the Pioneer Venus Orbiter (PVO) were used to derive upward flow and acceleration of H(+), D(+) and O(+) within the nightside ionosphere of Venus. The measurements revealed that the polarization electric field in the ionosphere produced the principal upward force on these light ions. The resulting vertical flow of H(+) and D(+) was found to be the dominant escape mechanism of hydrogen and deuterium, corresponding to loss rates consistent with large oceans in early Venus. Other electrodynamic forces were unimportant because the plasma beta in the nightside ionosphere of Venus is much greater than one. Although the plasma beta is also greater than one on Titan, ion acceleration is expected to be more complex, especially because the subsolar point and the subflow points can be 180 degrees apart. Following what we learned at Venus, upward acceleration of light ions by the polarization electric field opposing gravity in the ionosphere of Titan will be described. Additional electrodynamic forces resulting from the interaction of Saturn's magnetosphere with Titan's ionosphere will be examined using a recent hybrid model.

  1. A cometary ionosphere model for Io

    NASA Technical Reports Server (NTRS)

    Cloutier, P. A.; Daniell, R. E., Jr.; Dessler, A. J.; Hill, T. W.

    1978-01-01

    A source for the ionosphere of Io is proposed based on the assumption that the satellite is rather moonlike but continuously bombarded by intense fluxes of energetic particles, which makes its surface electrically conducting so that a significant Birkeland current is drawn up along magnetic field lines from Jupiter's ionosphere. It is suggested that the ion current is neutralized upon contact with Io's surface and that subsequent sputtering of this material from the surface supplies the satellite's neutral atmosphere. A model for the generation and maintenance of Io's ionosphere is outlined, according to which the structure of the ionosphere is determined by the impact of energetic trapped electrons from the Jovian magnetosphere and the ram pressure of the corotational magnetospheric wind. The first of these two processes provides the main ionization mechanism, while the second compresses the upstream (or 'nighttime') ionosphere via Alfven's critical-velocity phenomenon. It is concluded that Io's ionosphere is more nearly analogous to the coma and tail of a comet in the solar wind than to the earthlike case of a permanent gravitationally bound ionosphere.

  2. Investigation of Tsunami-Ionospheric Coupling Efficiency

    NASA Astrophysics Data System (ADS)

    Fisher, D. J.; Grawe, M.; Makela, J. J.; Coisson, P.; Rolland, L.; Rakoto, V.; Lognonne, P. H.

    2014-12-01

    Recent studies have shown that coupling exists between ocean tsunamis and the upper atmosphere, opening up the possibility of tsunami monitoring through observing the ionosphere. Several measurement techniques have demonstrated the effects of this coupling in the ionosphere. Here, we present data from two techniques that allow for deducing properties of a tsunami from the ionosphere (e.g., wavelength, orientation, and velocity), namely total electron content (TEC) measurements from dual-frequency GPS receivers and ionospheric imaging through monitoring the airglow layers surrounding the earth. However, a quantitative relationship between the wave amplitudes observed in the ionosphere and the height of the tsunami remains elusive. Ionospheric signatures from two tsunamis in the Pacific Ocean, caused by the 2011 Tohoku and 2012 Haida Gwaii earthquakes, have been observed in airglow imaging systems and a network of dual-frequency GPS receivers located in Hawaii. These two events provide excellent test cases for the study of tsunami-ionospheric coupling efficiency, most notably the effects of the relative orientation between the tsunami-induced gravity waves and the Earth's magnetic field. We present a quantitative comparison of the TEC and airglow intensity variation from these events, including results from tsunami normal mode summation modeling.

  3. Coupling of Earth's Atmosphere and Ionosphere

    NASA Astrophysics Data System (ADS)

    Singh, A. K.

    2012-12-01

    The coupling between the Earth's atmosphere and ionosphere is very complex and many aspects are not well understood till date. Recent measurements show that coupling influences both the electron density and electrical conductivity. The ionosphere reacts to various natural hazards related phenomena such as lightening discharges, thunderstorms, high-power explosion, earthquakes, volcano eruptions, and typhoons through a chain of interconnected processes in the lithosphere-atmosphere-ionosphere interaction system. The precipitation of magnetospheric electrons affects higher latitudes while the radioactive elements emitted during the earthquakes affect electron density and conductivity in the lower atmosphere. Thunderstorms and lightning discharges play a major role in transferring energy from the atmosphere to the ionosphere and in establishing electrical coupling between atmosphere and ionosphere through the global electric circuit (GEC). Electrical processes occurring in the atmosphere couple the atmosphere and ionosphere, because both DC and AC effects operate at the speed of light. The electrostatic and electromagnetic field changes in global electric circuit arise from thunderstorm, lightning discharges, and optical emissions in the mesosphere. In the present paper, our present understanding of how various processes play pivotal role in energy transfer from the lower atmosphere to the ionosphere would be briefly reviewed.

  4. Stratospheric Observatory For Infrared Astronomy (SOFIA). Phase A: System concept description

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Infrared astronomers have made significant discoveries using the NASA/Ames Research Center C-141 Kuiper airborne Observatory (KAO) with its 0.91-meter telescope. The need for a 3-meter class airborne observatory has been established to improve astronomy data gathering capability. The new system envisioned by NASA and the international community of astronomers will be known as the Stratospheric Observatory for Infrared Astronomy (SOFIA). The platform of choice for SOFIA is a modified Boeing 747SP. SOFIA is viewed as a logical progression from the KAO. Potentially, a 3-meter telescope operating at the altitude achievable by the 747SP aircraft can be 11 times more sensitive than the KAO, can have 3.3 times better angular resolution, and will allow observations of compact sources in a volume of space up to 36 times that of the KAO. The KAO has enabled detection of about 15 percent of the far infrared IRAS survey point-sources; SOFIA should be able to detect them all. This document presents the results of in-house ARC and contracted concept definition studies for SOFIA. Using the ARC-based Kuiper Airborne Observatory as a basis for both SOFIA design and operations concepts, the SOFIA system concept has been developed with a view toward demonstrating mission and technical feasibility, and preparing preliminary cost estimates. The reference concept developed is not intended to represent final design, and should be treated accordingly. The most important products of this study, other than demonstration of system feasibility, are the understanding of system trade-offs and the development of confidence in the technology base that exists to move forward with a program leading to implementation of the Stratospheric Observatory for Infrared Astronomy (SOFIA).

  5. Applying Squeaky-Wheel Optimization Schedule Airborne Astronomy Observations

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy; Kuerklue, Elif

    2004-01-01

    We apply the Squeaky Wheel Optimization (SWO) algorithm to the problem of scheduling astronomy observations for the Stratospheric Observatory for Infrared Astronomy, an airborne observatory. The problem contains complex constraints relating the feasibility of an astronomical observation to the position and time at which the observation begins, telescope elevation limits, special use airspace, and available fuel. Solving the problem requires making discrete choices (e.g. selection and sequencing of observations) and continuous ones (e.g. takeoff time and setting up observations by repositioning the aircraft). The problem also includes optimization criteria such as maximizing observing time while simultaneously minimizing total flight time. Previous approaches to the problem fail to scale when accounting for all constraints. We describe how to customize SWO to solve this problem, and show that it finds better flight plans, often with less computation time, than previous approaches.

  6. Near-field co-seismic ionospheric response due to the northern Chile Mw 8.1 Pisagua earthquake on April 1, 2014 from GPS observations

    NASA Astrophysics Data System (ADS)

    Reddy, C. D.; Sunil, A. S.; González, G.; Shrivastava, Mahesh N.; Moreno, Marcos

    2015-11-01

    Large earthquakes can induce near and far-field ionospheric perturbations by direct/secondary acoustic and gravity waves through Lithosphere-Atmosphere-Ionosphere (LAI) coupling. We analyze co-seismic induced ionospheric TEC perturbations following the northern Chile Mw 8.1 Pisagua earthquake occurred on April 1, 2014. The continuous Global Positioning System (GPS) data at 15 sites from the Integrated Plate Boundary Observatory Chile (IPOC) and International GPS Service (IGS) GPS networks have been used in the present study. The nearest GPS site iqqe, ~98 km away from the epicenter, recorded the ionospheric disturbance 12 min after the event. The maximum co-seismic induced peak-to-peak TEC amplitude is ~1.25 TECU (1TECU=1016 electrons/m2), and the perturbations are confined to less than 1000 km radius around the epicenter. The observed horizontal velocity of TEC perturbations has been determined as ~1180 m/s. We could also discern the signatures of acoustic gravity waves (AGW) with velocity~650 m/s and frequency~2 mHz. The ionospheric signal components due to Rayleigh and/or Tsunami waves could not be observed. This contribution presents characteristics of near-field co-seismic ionospheric response due to the 2014 Pisagua earthquake.

  7. Ionospheric irregularity physics modelling. Memorandum report

    SciTech Connect

    Ossakow, S.L.; Keskinen, M.J.; Zalesak, S.T.

    1982-02-09

    Theoretical and numerical simulation techniques have been employed to study ionospheric F region plasma cloud striation phenomena, equatorial spread F phenomena, and high latitude diffuse auroral F region irregularity phenomena. Each of these phenomena can cause scintillation effects. The results and ideas from these studies are state-of-the-art, agree well with experimental observations, and have induced experimentalists to look for theoretically predicted results. One conclusion that can be drawn from these studies is that ionospheric irregularity phenomena can be modelled from a first principles physics point of view. Theoretical and numerical simulation results from the aforementioned ionospheric irregularity areas will be presented.

  8. Ionosphere of Mars observed by Mars Express.

    NASA Astrophysics Data System (ADS)

    Dubinin, Eduard; Fraenz, Markus; Andrews, Dave; Morgan, Dave

    2016-04-01

    The Martian ionosphere is studied at different solar zenith angles using the local electron number densities and total electron content (TEC) derived from the observations by MARSIS onboard Mars Express. The data are complemented by the ASPERA-3 observations which provide us with the information about upward/downward velocity of the low-energy ions and electron precipitation. We consider the Mars Express observations at different solar cycle intervals. Different factors which influence the ionosphere dynamics are analyzed. The focus is made on a role of the crustal magnetic field on the Martian ionosphere and its influence on ion escape.

  9. Ionospheric calibration for single frequency altimeter measurements

    NASA Astrophysics Data System (ADS)

    Schreiner, William S.; Born, George H.

    1993-08-01

    This report investigates the potential of using Global Positioning System (GPS) data and a model of the ionosphere to supply a measure of the sub-satellite Total Electron Current (TEC) of the required accuracy (10 TECU rms) for the purpose of calibrating single frequency radar altimeter measurements. Since climatological (monthly mean) models are known to be in error by as much as 50 percent, this work focused on the Parameterized Real-Time Ionospheric Specification Model (PRISM) which has the capability to improve model accuracy by ingesting (adjusting to) in situ ionospheric measurements. A set of globally distributed TEC measurements were generated using GPS data and were used as input to improve the accuracy of the PRISM model. The adjusted PRISM TEC values were compared to TOPEX dual frequency TEC measurements (which are considered truth) for a number of TOPEX sub-satellite tracks. The adjusted PRISM values generally compared to the TOPEX measurements within the 10 TECU accuracy requirements when the sub-satellite track passed within 300 to 400 km of the GPS TEC data or when the track passed through a night time ionosphere. However, when the sub-satellite points were greater than 300 to 400 km away from the GPS TEC data or when a local noon ionosphere was sampled, the adjusted PRISM values generally differed by greater than 10 TECU rms with data excursions from the TOPEX TEC measurements of as much as 40 TECU (an 8 cm path delay error at K band). Therefore, it can be concluded from this analysis that an unrealistically large number of GPS stations would be needed to predict sub-satellite TEC at the 10 TECU level in the day time ionosphere using a model such as PRISM. However, a technique currently being studied at the Jet Propulsion Laboratory (JPL) may provide a means of supplying adequate TEC data to meet the 10 TECU ionospheric correction accuracy when using a realistic number of ionospheric stations. This method involves using global GPS TEC data to

  10. Ionospheric calibration for single frequency altimeter measurements

    NASA Technical Reports Server (NTRS)

    Schreiner, William S.; Born, George H.

    1993-01-01

    This report investigates the potential of using Global Positioning System (GPS) data and a model of the ionosphere to supply a measure of the sub-satellite Total Electron Current (TEC) of the required accuracy (10 TECU rms) for the purpose of calibrating single frequency radar altimeter measurements. Since climatological (monthly mean) models are known to be in error by as much as 50 percent, this work focused on the Parameterized Real-Time Ionospheric Specification Model (PRISM) which has the capability to improve model accuracy by ingesting (adjusting to) in situ ionospheric measurements. A set of globally distributed TEC measurements were generated using GPS data and were used as input to improve the accuracy of the PRISM model. The adjusted PRISM TEC values were compared to TOPEX dual frequency TEC measurements (which are considered truth) for a number of TOPEX sub-satellite tracks. The adjusted PRISM values generally compared to the TOPEX measurements within the 10 TECU accuracy requirements when the sub-satellite track passed within 300 to 400 km of the GPS TEC data or when the track passed through a night time ionosphere. However, when the sub-satellite points were greater than 300 to 400 km away from the GPS TEC data or when a local noon ionosphere was sampled, the adjusted PRISM values generally differed by greater than 10 TECU rms with data excursions from the TOPEX TEC measurements of as much as 40 TECU (an 8 cm path delay error at K band). Therefore, it can be concluded from this analysis that an unrealistically large number of GPS stations would be needed to predict sub-satellite TEC at the 10 TECU level in the day time ionosphere using a model such as PRISM. However, a technique currently being studied at the Jet Propulsion Laboratory (JPL) may provide a means of supplying adequate TEC data to meet the 10 TECU ionospheric correction accuracy when using a realistic number of ionospheric stations. This method involves using global GPS TEC data to

  11. The solar wind-magnetosphere-ionosphere system

    PubMed

    Lyon

    2000-06-16

    The solar wind, magnetosphere, and ionosphere form a single system driven by the transfer of energy and momentum from the solar wind to the magnetosphere and ionosphere. Variations in the solar wind can lead to disruptions of space- and ground-based systems caused by enhanced currents flowing into the ionosphere and increased radiation in the near-Earth environment. The coupling between the solar wind and the magnetosphere is mediated and controlled by the magnetic field in the solar wind through the process of magnetic reconnection. Understanding of the global behavior of this system has improved markedly in the recent past from coordinated observations with a constellation of satellite and ground instruments.

  12. Physics of planetary atmospheres and ionospheres

    NASA Technical Reports Server (NTRS)

    Bauer, S. J.

    1981-01-01

    The traditional atmospheric regions, the distinction between homosphere and heterosphere, and changing atmospheric composition are discussed. The validity of the barometric law based on a Maxwell-Boltzmann distribution, for the major part of a planetary atmosphere and its breakdown in the exosphere due to escape of atmospheric particles is considered. The formation and maintenance of photochemical and diffusion-controlled ionospheric layers are treated. Their applicability to planetary ionospheres is dealt with. The spatial extent of magnetic and nonmagnetic planet ionospheres is investigated. Thermal and nonthermal processes responsible for the mass loss of planetary atmospheres are surveyed.

  13. Homogeneity of geomagnetic variations at the Sodankyla Observatory

    NASA Astrophysics Data System (ADS)

    Kauristie, Kirsti; Ernst, Tomasz; Jankowski, Jerzy; Viljanen, Ari; Kultima, Johannes; Pirjola, Risto; Kataja, Eero

    Geomagnetic variations and the associated electric field were recorded at four temporary stations around the Sodankyla Geophysical Observatory for ten days in August 1988. The distance from each station to the observatory was about 30 km. The main purpose was to study the spatial homogeneity of magnetic variations observed at Sodankyla, i.e., to find out whether there are any local induction effects in the recordings of Sodankyla. Analysis of geomagnetic induction vectors indicates a large-scale induction anomaly but in the 30 km scale the variations are practically homogeneous for periods ranging from 100 to 2500 s. According to magnetotelluric calculations, the conductivity structure at the stations is three-dimensional. The inhomogeneity of the primary source field due to ionospheric currents can be significant in the vicinity of Sodankyla. It causes problems in induction vector and magnetotelluric calculations. Standard deviation between recordings at different stations are calculated using only carefully selected events having a homogenous source field. Theoretical estimates indicate that spatial variations of the primary field may exceed the standard deviations obtained.

  14. GEOSCOPE Observatory Recent Developments

    NASA Astrophysics Data System (ADS)

    Leroy, N.; Pardo, C.; Bonaime, S.; Stutzmann, E.; Maggi, A.

    2010-12-01

    The GEOSCOPE observatory consists of a global seismic network and a data center. The 31 GEOSCOPE stations are installed in 19 countries, across all continents and on islands throughout the oceans. They are equipped with three component very broadband seismometers (STS1 or STS2) and 24 or 26 bit digitizers, as required by the Federation of Seismic Digital Network (FDSN). In most stations, a pressure gauge and a thermometer are also installed. Currently, 23 stations send data in real or near real time to GEOSCOPE Data Center and tsunami warning centers. In 2009, two stations (SSB and PPTF) have been equipped with warpless base plates. Analysis of one year of data shows that the new installation decreases long period noise (20s to 1000s) by 10 db on horizontal components. SSB is now rated in the top ten long period stations for horizontal components according to the LDEO criteria. In 2010, Stations COYC, PEL and RER have been upgraded with Q330HR, Metrozet electronics and warpless base plates. They have been calibrated with the calibration table CT-EW1 and the software jSeisCal and Calex-EW. Aluminum jars are now installed instead of glass bells. A vacuum of 100 mbars is applied in the jars which improves thermal insulation of the seismometers and reduces moisture and long-term corrosion in the sensor. A new station RODM has just been installed in Rodrigues Island in Mauritius with standard Geoscope STS2 setup: STS2 seismometer on a granite base plate and covered by cooking pot and thermal insulation, it is connected to Q330HR digitizer, active lightning protection, Seiscomp PC and real-time internet connection. Continuous data of all stations are collected in real time or with a delay by the GEOSCOPE Data Center in Paris where they are validated, archived and made available to the international scientific community. Data are freely available to users by different interfaces according data types (see : http://geoscope.ipgp.fr) - Continuous data in real time coming

  15. Development of solar tower observatories

    NASA Astrophysics Data System (ADS)

    Wolfschmidt, Gudrun

    Because the horizontal solar telescope, the Snow Telescope in Yerkes Observatory, was affected by air-currents from the warmed-up soil, George Ellery Hale had the idea of a tower telescope. In 1904, the 60-foot tower in Mt. Wilson was ready, in 1908 the 150-foot tower was built with the help of the Carnegie foundation. After World War I, Germany made heavy efforts to regain its former strong position in the field of science. Already in December 1919 - after the spectacular result of the English eclipse expedition in October 1919 - Erwin Finlay-Freundlich started a successful fund raising (“Einstein-Stiftungrdquo;) among German industrialists. The company Zeiss in Jena was responsible for the instrumentation of the 20-m solar tower, built in 1920-22. The optical design of the Einstein Tower in respect to light intensity surpassed even the Mt. Wilson solar observatory. Also abroad solar tower observatories were built in the 1920s: Utrecht,The Netherlands (1922), Canberra, Australia (1924), Arcetri, Italy (1926), Pasadena, California (1926) and Tokyo, Japan (1928). In the thirties, solar physics became important because of the solar maximum in 1938 and the new observational possibilities created by Bernard Lyot. At the end of the 1930s, Karl-Otto Kiepenheuer proposed to establish a solar tower observatory on Wendelstein in order to improve the predictions of radio interference by observing sunspots. By stressing the importance of the solar research for war efforts, Otto Heckmann of Göttingen observatory finally succeeded in winning the “Reichsluftfahrtministerium” to finance several solar observatories, like Wendelstein, Hainberg/Göttingen, Kanzelhöhe/Villach, and Schauinsland/Freiburg. Solar astronomy profited by the foundation of the new observatories - four of them existed still after the war. Abroad only the solar observatories of Oxford (1935) and the 50 foot tower of the McMath-Hulbert Observatory, University of Michigan (1936) should be mentioned. Only

  16. Ionosphere/thermosphere heating determined from dynamic magnetosphere-ionosphere/thermosphere coupling

    NASA Astrophysics Data System (ADS)

    Tu, Jiannan; Song, Paul; Vasyliūnas, Vytenis M.

    2011-09-01

    Ionosphere/thermosphere heating driven by magnetospheric convection is investigated through a three-fluid inductive (including Faraday's law) approach to describing magnetosphere-ionosphere/thermosphere coupling, for a 1-D stratified ionosphere/thermosphere in this initial study. It is shown that the response of the ionosphere/thermosphere and thus the heating is dynamic and height-dependent. The heating is essentially frictional in nature rather than Joule heating as commonly assumed. The heating rate reaches a quasi-steady state after about 25 Alfvén travel times. During the dynamic period, the heating can be enhanced and displays peaks at multiple times due to wave reflections. The dynamic heating rate can be more than twice greater than the quasi-steady state value. The heating is strongest in the E-layer but the heating rate per unit mass is concentrated around the F-layer peak height. This implies a potential mechanism of driving O+ upflow from O+ rich F-layer. It is shown that the ionosphere/thermosphere heating caused by the magnetosphere-ionosphere coupling can be simply evaluated through the relative velocity between the plasma and neutrals without invoking field-aligned currents, ionospheric conductance, and electric field. The present study provides understanding of the dynamic magnetosphere-ionosphere/thermosphere coupling from the ionospheric/thermospheric view in addition to magnetospheric perspectives.

  17. Ionospheric and magnetospheric effects of solar flares monitored by ground-based riometer and magnetometers

    NASA Astrophysics Data System (ADS)

    Ronan Coelho Stekel, Tardelli; Schuch, Nelson Jorge; Echer, Ezequiel; Guarnieri, Fernando; Makita, Kazuo; Espindola Antunes, Cassio; Moro, Juliano; Machado Paulo, Claudio

    The solar flare incidence follows a behavior similar to the solar cycle activity, which results in periodic disturbances on the Earth's ionosphere and magnetosphere. The correlation of this phenomenon can provide important information about the magnetosphere, the Sun/Earth interaction, as well as events occurring in the ionosphere which can, for instance, generate disturbances in telecommunications, small satellites or even in the space weather. Riometer and magnetometers data analysis can provide useful way for measuring and understanding the effects of solar flare radiation in the ionosphere and magnetosphere. The Solar Flare effect (SFE) is associated with the sudden change of ionospheric currents caused by the extra ionization produced by soft X-ray (0.1 to 9.0 nm) and EUV (9.0 to 100.0 nm) radiation from the solar flare. The objective of this work is to present the correlation of the ionospheric and magnetospheric (H, D, Z) sudden disturbances due to high-intensity solar flares (M and X class), that can emit up to 1032 ergs of energy. For this purpose, analysis were performed for the riometer and magnetometers dedicated to study the Solar-Earth interactions at the Southern Space Observatory (SSO/CRS/INPE -MCT), (29.4° S, 53.8° W, 480m a.s.l), São Martinho da a Serra, RS, Brazil. To identify and investigate the sudden radiation increase caused by the solar flare, the X-ray data (0.1 to 0.8 nm) from GOES Satellites and the EUV data (26.0 to 34.0 nm and 0.1 to 50.0 nm) from the Solar EUV Monitor (SEM) on the SOHO spacecraft are correlated. With the analysis of these ground-based instruments and spacecrafts data, the correlation of the solar activity and the magnetospheric and ionospheric disturbances were performed, as for the Sudden Ionospheric Disturbance (SID) and Magnetic Crochet about 60% D-component variation during a large solar flare was observed.

  18. Observatory Bibliographies as Research Tools

    NASA Astrophysics Data System (ADS)

    Rots, Arnold H.; Winkelman, S. L.

    2013-01-01

    Traditionally, observatory bibliographies were maintained to provide insight in how successful a observatory is as measured by its prominence in the (refereed) literature. When we set up the bibliographic database for the Chandra X-ray Observatory (http://cxc.harvard.edu/cgi-gen/cda/bibliography) as part of the Chandra Data Archive ((http://cxc.harvard.edu/cda/), very early in the mission, our objective was to make it primarily a useful tool for our user community. To achieve this we are: (1) casting a very wide net in collecting Chandra-related publications; (2) including for each literature reference in the database a wealth of metadata that is useful for the users; and (3) providing specific links between the articles and the datasets in the archive that they use. As a result our users are able to browse the literature and the data archive simultaneously. As an added bonus, the rich metadata content and data links have also allowed us to assemble more meaningful statistics about the scientific efficacy of the observatory. In all this we collaborate closely with the Astrophysics Data System (ADS). Among the plans for future enhancement are the inclusion of press releases and the Chandra image gallery, linking with ADS semantic searching tools, full-text metadata mining, and linking with other observatories' bibliographies. This work is supported by NASA contract NAS8-03060 (CXC) and depends critically on the services provided by the ADS.

  19. TIMED Contributions to the NASA Sun-Solar System Connections Great Observatory

    NASA Astrophysics Data System (ADS)

    Christensen, A. B.; Kozyra, J.; Paxton, L.; Talaat, E.; Yee, J.

    2005-12-01

    TIMED, the terrestrial anchor of NASA's Sun-Solar System Great Observatory, provides comprehensive global measurements of atmospheric properties required for a quantitative understanding the physical, dynamic, energetic and thermal structure of Earth's mesosphere, thermosphere, and ionosphere. This region, located between 60 and 400 km altitude, is the interface between interplanetary processes above and the stratosphere and lower atmosphere below. Thus it plays a uniquely important role in the scientific study of Sun-Solar System connections and in bridging the programmatic gap between space physics and Earth science. The current SSSC Great Observatory comprises a fleet of widely deployed solar, heliospheric, geospace and planetary spacecraft working together to help understand solar activity and its interaction with planetary systems. It is an evolving set as new spacecraft are added and old spacecraft are removed. To address the fundamental physical processes of the space environment and to understand the SSSC system- wide behavior requires multiple observation posts, rapid access to data, development and application of models, theory, and simulations. We will discuss new scientific insights and discoveries from the TIMED mission to illustrate the manifestations of complex coupling processes and to demonstrate the value of the Great Observatory concept. The topics include: (1) observations of the spatial and temporal extent of severe equatorial ionospheric plasma depletions which occur during superstorms using observations of bubbles from TIMED/GUVI with the DMSP and ROCSAT-1 satellites. (2) Mid-latitude aurora, and (3) global thermospheric/ionospheric coupling and (4) the variability of geospace considering the flow of energy from the sun through to its deposition in the upper atmosphere during large geomagnetic storms.

  20. PHARUS airborne SAR concept

    NASA Astrophysics Data System (ADS)

    Snoeij, Paul; Pouwels, Henk; Koomen, Peter J.; Hoogeboom, Peter

    1995-11-01

    PHARUS (phased array universal SAR) is an airborne SAR concept which is being developed in the Netherlands. The PHARUS system differs from other airborne SARs by the use of a phased array antenna, which provides both for the flexibility in the design as well as for a compact, light-weight instrument that can be carried on small aircraft. The concept allows for the construction of airborne SAR systems on a common generic basis but tailored to specific user needs and can be seen as a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna. The whole approach is aimed at providing an economic and yet technically sophisticated solution to remote sensing or surveying needs of a specific user. The solid state phased array antenna consists of a collection of radiating patches; the design flexibility for a large part resides in the freedom to choose the number of patches, and thereby the essential radar performance parameters such as resolution and swath width. Another consequence of the use of the phased array antenna is the system's compactness and the possibility to rigidly mount it on a small aircraft. The use of small aircraft of course considerably improves the cost/benefit ratio of the use of airborne SAR. Flight altitude of the system is flexible between about 7,000 and 40,000 feet, giving much operational freedom within the meteo and airspace control limits. In the PHARUS concept the airborne segment is complemented by a ground segment, which consists of a SAR processor, possibly extended by a matching image processing package. (A quick look image is available in real-time on board the aircraft.) The SAR processor is UNIX based and runs on easily available hardware (SUN station). Although the additional image processing software is available, the SAR processing software is nevertheless designed to be able to interface with commercially available image processing software, as well as being able

  1. Australian network of magnetic observatories

    NASA Astrophysics Data System (ADS)

    Barton, C. E.

    Six magnetic observatories are presently operated by the Australian Bureau of Mineral Resources, Geology and Geophysics (BMR), with assistance from various other organizations. Variometer recordings are made of three or more elements of the field at minute intervals, and absolute measurements are made weekly. There are four observatories on the continent (Canberra, Gnangara, Charters Towers, and Learmonth), one on Macquarie Island, and one at Mawson Station in eastern Antarctica (Figure 1). In addition, semiweekly absolute observations of the field (D, H, and F) are made at the other two permanent Australian Antarctic bases (Casey and Davis). A three-axis fluxgate magnetometer (EDA Electronics, Toronto , Canada) is operated independently by the Upper Atmosphere Physics group at Davis. Monthly mean values, K indices, and information about magnetic disturbances are published monthly in the BMR Geophysical Observatory Report.

  2. The log-periodic array at the Clark Lake Radio Observatory

    NASA Technical Reports Server (NTRS)

    Erickson, W. C.; Kuiper, T. B. H.

    1973-01-01

    A log-periodic array, 3 km in length, is operating at Clark Lake Radio Observatory. It makes one-dimensional sweeps of the solar brightness distribution in the frequency range 20 to 65 MHz once per sec. The phasing of the array and the receiving system are described, as well as how the dynamic spectra are analyzed for the positions of solar radio sources. Simultaneous measurements at many frequencies enable the observer to remove the effects of ionospheric refraction and to obtain fundamental positions to an accuracy of about one arc min at decametric wavelengths. Fundamental positions are given for Cassiopeia A.

  3. Intercepted signals for ionospheric science

    NASA Astrophysics Data System (ADS)

    Lind, F. D.; Erickson, P. J.; Coster, A. J.; Foster, J. C.; Marchese, J. R.; Berkowitz, Z.; Sahr, J. D.

    2013-05-01

    The ISIS array (Intercepted Signals for Ionospheric Science) is a distributed, coherent software radio array designed for the study of geospace phenomena by observing the scatter of ambient radio frequency (RF) signals. ISIS data acquisition and analysis is performed using the MIDAS-M platform (Millstone Data Acquisition System - Mobile). Observations of RF signals can be performed between HF and L-band using the Array nodes and appropriate antennas. The deployment of the Array focuses on observations of the plasmasphere boundary layer. We discuss the concept of the coherent software radio array, describe the ISIS hardware, and give examples of data from the system for selected applications. In particular, we include the first observations of E region irregularities using the Array. We also present single-site passive radar observations of both meteor trails and E region irregularities using adaptive filtering techniques.

  4. Auroral pulsations from ionospheric winds

    NASA Technical Reports Server (NTRS)

    Nakada, M. P.

    1989-01-01

    The possibility that auroral pulsations are due to oscillatory electrical circuits in the ionosphere that are driven by the negative resistance of jet stream winds is examined. For the condenser plates, the highly conducting surfaces above the edges of the jet stream are postulated. The dielectric constant of the plasma between the plates is quite large. The current that is driven perpendicular to and by the jet stream closes along the plates and through Pedersen currents in the F region above the stream. This closed loop gives the inductance and resistance for the circuit. Periods of oscillation for this circuit appear to be in the range of Pc 1 to Pc 3. In accord with observations, this circuit appears to be able to limit the brightness of pulsations.

  5. Magnetic Earth Ionosphere Resonant Frequencies

    NASA Technical Reports Server (NTRS)

    Spaniol, Craig

    1994-01-01

    The Community College Division is pleased to report progress of NASA funded research at West Virginia State College. During this reporting period, the project research group has continued with activities to develop instrumentation capability designed to monitor resonant cavity frequencies in the atmospheric region between the Earth's surface and the ionosphere. In addition, the project's principal investigator, Dr. Craig Spaniol, and NASA technical officer, Dr. John Sutton, have written and published technical papers intended to expand the scientific and technical framework needed for project research. This research continues to provide an excellent example of government and education working together to provide significant research in the college environment. This cooperative effort has provided many students with technical project work which compliments their education.

  6. Airborne Oceanographic Lidar System

    NASA Technical Reports Server (NTRS)

    Bressel, C.; Itzkan, I.; Nunes, J. E.; Hoge, F.

    1977-01-01

    The Airborne Oceanographic Lidar (AOL), a spatially scanning range-gated device installed on board a NASA C-54 aircraft, is described. The AOL system is capable of measuring topographical relief or water depth (bathymetry) with a range resolution of plus or minus 0.3 m in the vertical dimension. The system may also be used to measure fluorescent spectral signatures from 3500 to 8000 A with a resolution of 100 A. Potential applications of the AOL, including sea state measurements, water transparency assessments, oil spill identification, effluent identification and crop cover assessment are also mentioned.

  7. Development and global oscillations of cometary ionospheres

    SciTech Connect

    Houpis, H.L.F.; Mendis, D.A.

    1981-02-01

    Representing the cometary ionosphere by a single fluid model characterized by an average ionization time scale, we have studied both its development as a comet approaches the sun and its response to sudden changes in the solar wind conditions. Three different nuclear sizes, small average, and very large, as well as three different modes of energy addition to the atmosphere, adiabatic, isothermal, and suprathermal, are considered. The crucial parameter determining both the nature and the size of the ionosphere is the average ionization time scale within the ionosphere. We identify two different ionization time scales: one during ''quiet'' solar wind conditions when photoionization is the principal source of ionization there, and a secod, much shorter time scale, subsequent to the encounter by a comet of a solar wind high-speed stream, when a beam of energetic electrons discharged from the comet's tail into the ionosphere is the main ionizing agent.

  8. Magnetic Fluctuations in the Martian Ionosphere

    NASA Technical Reports Server (NTRS)

    Espley, Jared

    2010-01-01

    The Martian ionosphere is influenced by both the solar wind and the regional magnetic fields present in the Martian crust. Both influences ought to cause time variable changes in the magnetic fields present in the ionosphere. I report observations of these magnetic field fluctuations in the Martian ionosphere. I use data from the Mars Global Surveyor magnetometer instrument. By using data from the aerobraking low altitude passes (approx. 200 km) I find that there are numerous fluctuations both near and far from the strong crustal sources. Using data from the 400 km altitude mapping phase (which is near the topside of the primary ionosphere), I look at the comparative strength of the fluctuations relative to the solar wind and temporal variations. I discuss which wave modes and instabilities could be contributing to these fluctuations. I also discuss the implications of these fluctuations for understanding energy transfer in the Martian system and the effects on atmospheric escape.

  9. Space weather. Ionospheric control of magnetotail reconnection.

    PubMed

    Lotko, William; Smith, Ryan H; Zhang, Binzheng; Ouellette, Jeremy E; Brambles, Oliver J; Lyon, John G

    2014-07-11

    Observed distributions of high-speed plasma flows at distances of 10 to 30 Earth radii (R(E)) in Earth's magnetotail neutral sheet are highly skewed toward the premidnight sector. The flows are a product of the magnetic reconnection process that converts magnetic energy stored in the magnetotail into plasma kinetic and thermal energy. We show, using global numerical simulations, that the electrodynamic interaction between Earth's magnetosphere and ionosphere produces an asymmetry consistent with observed distributions in nightside reconnection and plasmasheet flows and in accompanying ionospheric convection. The primary causal agent is the meridional gradient in the ionospheric Hall conductance which, through the Cowling effect, regulates the distribution of electrical currents flowing within and between the ionosphere and magnetotail. PMID:25013068

  10. Ionospheric Stimulation By High Power Radio Waves

    NASA Astrophysics Data System (ADS)

    Minami, S.; Nishino, M.; Suzuki, Y.; Sato, S.; Tanikawa, T.; Nakamura, Y.; Wong, A. Y.

    1999-01-01

    We have performed an experiment to artificially stimulate the ionosphere using higher power radio waves at the HIPAS (High Power Auroral Stimulation) facility in Alaska. A radio transmission of 2.85 MHz was made at 80 MW (ERP). Diagnostics were made at the other site located 35 km from the transmission site. The results of cross-correlating the excited HF wave and observed with an 8 channel, 30 MHz scanning cosmic radio noise absorption records revealed the excited height of 90 km. Also atmospheric pressure waves observed on the ground show evident propagation of pressure waves which are generated in the ionosphere by the high-power HF wave. The results determine the excitation height of 90 km in the ionosphere and show evidence of the pressure wave coupling between the ionosphere and the lower atmosphere for periods of 10 min

  11. The theory of ionospheric focused heating

    NASA Technical Reports Server (NTRS)

    Bernhardt, P. A.; Duncan, L. M.

    1987-01-01

    Ionospheric modification by high power radio waves and by chemical releases are combined in a theoretical study of ionospheric focused heating. The release of materials which promote electron-ion recombination creates a hole in the bottomside ionosphere. The ionospheric hole focuses high power radio waves from a ground-based transmitter to give a 20 dB or greater enhancement in power density. The intense radio beam excites atomic oxygen by collisions with accelerated electrons. Airglow from the excited oxygen provides a visible trace of the focused beam. The large increase in the intensity of the radio beam stimulates new wave-plasma interactions. Numerical simulations show that the threshold for the two-plasmon decay instability is exceeded. The interaction of the pump electromagnetic wave with the backward plasmon produces a scattered electromagnetic wave at 3/2 the pump frequency. The scattered wave provides a unique signature of the two-plasmon decay process for ground-based detection.

  12. Wave coupling of atmosphere-ionosphere system

    NASA Astrophysics Data System (ADS)

    Goncharenko, L. P.

    2011-12-01

    The dynamic coupling of atmosphere-ionosphere system is a complex interdisciplinary problem. Current thinking suggests that the upward propagation of internal atmospheric waves (planetary waves, tides, gravity waves) from the lower atmosphere is an essential source of energy and momentum for the thermosphere and embedded ionosphere. Studies over the last decade presented fascinating experimental and modeling evidence of global coupling from the troposphere to mesosphere, thermosphere and ionosphere. They were enabled by unprecedented availability of satellite data, in particularly from TIMED, MLS, CHAMP, and GRACE, focused experimental campaigns from ground-based instruments, and major advances in global coupling models. This paper will summarize several developments over the past decade, including non-migrating structures in the ionosphere and thermosphere, advances in studies of gravity waves and planetary waves, and their implications for better understanding of ITM. The paper will also identify questions that need to be answered in the future, and outline promising topics of future development.

  13. The upper atmosphere and ionosphere of Mars

    NASA Technical Reports Server (NTRS)

    Brace, Larry H.

    1992-01-01

    The topics discussed include the following: the dynamic atmosphere of Mars; possible similarities with Earth and Venus; the atmosphere and ionosphere of Mars; solar wind interactions; future approved missions; and possible future mission.

  14. Pulsating aurora: The importance of the ionosphere

    SciTech Connect

    Stenbaek-Nielsen, H.C.

    1980-05-01

    A number of different, but mainly optical, observations made in pulsating auroras are presented. These observations indicate that active ionospheric processes are likely to play an important role in causing and/or modifying pulsating aurora.

  15. Environmental Observatories and Hydrologic Modeling

    NASA Astrophysics Data System (ADS)

    Hooper, R. P.; Duncan, J. M.

    2006-12-01

    During the past several years, the environmental sciences community has been attempting to design large- scale obsevatories that will transform the science. A watershed-based observatory has emerged as an effective landscape unit for a broad range of environmental sciences and engineering. For an effective observatory, modeling is a central requirement because models are precise statements of the hypothesized conceptual organization of watersheds and of the processes believed to be controlling hydrology of the watershed. Furthermore, models can serve to determine the value of existing data and the incremental value of any additional data to be collected. Given limited resources, such valuation is mandatory for an objective design of an observatory. Modeling is one part of a "digital watershed" that must be constructed for any observatory, a concept that has been developed by the CUAHSI Hydrologic Information Systems project. A digital watershed has three functions. First, it permits assembly of time series (such as stream discharge or precipitation measurements), static spatial coverages (such as topography), and dynamic fields (such as precipitation radar and other remotely sensed data). Second, based upon this common data description, a digital observatory permits multiple conceptualizations of the observatory to be created and to be stored. These conceptualizations could range from lumped box-and-arrow watershed models, to semi-distributed topographically based models, to three-dimensional finite element models. Finally, each conceptualization can lead to multiple models--that is, a set of equations that quantitatively describe hydrologic (or biogeochemical or geomorphologic) processes through libraries of tools that can be linked as workflow sequences. The advances in cyberinfrastructure that allow the storage of multiple conceptualizations and multiple model formulations of these conceptualizations promise to accelerate advances in environmental science both

  16. Remote Sensing of Ionosphere by IONOLAB Group

    NASA Astrophysics Data System (ADS)

    Arikan, Feza

    2016-07-01

    Ionosphere is a temporally and spatially varying, dispersive, anisotropic and inhomogeneous medium that is characterized primarily by its electron density distribution. Electron density is a complex function of spatial and temporal variations of solar, geomagnetic, and seismic activities. Ionosphere is the main source of error for navigation and positioning systems and satellite communication. Therefore, characterization and constant monitoring of variability of the ionosphere is of utmost importance for the performance improvement of these systems. Since ionospheric electron density is not a directly measurable quantity, an important derivable parameter is the Total Electron Content (TEC), which is used widely to characterize the ionosphere. TEC is proportional to the total number of electrons on a line crossing the atmosphere. IONOLAB is a research group is formed by Hacettepe University, Bilkent University and Kastamonu University, Turkey gathered to handle the challenges of the ionosphere using state-of-the-art remote sensing and signal processing techniques. IONOLAB group provides unique space weather services of IONOLAB-TEC, International Reference Ionosphere extended to Plasmasphere (IRI-Plas) model based IRI-Plas-MAP, IRI-Plas-STEC and Online IRI-Plas-2015 model at www.ionolab.org. IONOLAB group has been working for imaging and monitoring of ionospheric structure for the last 15 years. TEC is estimated from dual frequency GPS receivers as IONOLAB-TEC using IONOLAB-BIAS. For high spatio-temporal resolution 2-D imaging or mapping, IONOLAB-MAP algorithm is developed that uses automated Universal Kriging or Ordinary Kriging in which the experimental semivariogram is fitted to Matern Function with Particle Swarm Optimization (PSO). For 3-D imaging of ionosphere and 1-D vertical profiles of electron density, state-of-the-art IRI-Plas model based IONOLAB-CIT algorithm is developed for regional reconstruction that employs Kalman Filters for state

  17. High Energy Astronomy Observatory (HEAO)

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This is an artist's concept describing the High Energy Astronomy Observatory (HEAO). The HEAO project involved the launching of three unmarned scientific observatories into low Earth orbit between 1977 and 1979 to study some of the most intriguing mysteries of the universe; pulsars, black holes, neutron stars, and super nova. This concept was painted by Jack Hood of the Marshall Space Flight Center (MSFC). Hardware support for the imaging instruments was provided by American Science and Engineering. The HEAO spacecraft were built by TRW, Inc. under project management of the MSFC.

  18. The Compton Observatory Science Workshop

    NASA Technical Reports Server (NTRS)

    Shrader, Chris R. (Editor); Gehrels, Neil (Editor); Dennis, Brian (Editor)

    1992-01-01

    The Compton Observatory Science Workshop was held in Annapolis, Maryland on September 23-25, 1991. The primary purpose of the workshop was to provide a forum for the exchange of ideas and information among scientists with interests in various areas of high energy astrophysics, with emphasis on the scientific capabilities of the Compton Observatory. Early scientific results, as well as reports on in-flight instrument performance and calibrations are presented. Guest investigator data products, analysis techniques, and associated software were discussed. Scientific topics covered included active galaxies, cosmic gamma ray bursts, solar physics, pulsars, novae, supernovae, galactic binary sources, and diffuse galactic and extragalactic emission.

  19. Solar daily variation at geomagnetic observatories in Pakistan

    NASA Astrophysics Data System (ADS)

    Rahim, Zain; Kumbher, Abdul Salam

    2016-03-01

    A study of solar daily variation is performed using the famous Chapman-Miller method for solar cycles 22 & 23 (1986-2007). The objective is to study the characteristics of Sq variation at Pakistani geomagnetic observatories using solar harmonics and a more traditional five quietest day's method. The data recorded at the Karachi geomagnetic observatory for SC 22 and 23 and data sets from other Pakistani geomagnetic observatories; Sonmiani, Quetta and Islamabad are analyzed for H, D and Z components of the geomagnetic field. Except for the D and Z components at Karachi and Sonmiani and H component at Islamabad, the two solar daily variations correlated well with each other. Also, the synthesized daily variation from the solar harmonics of H, D and Z components explained the equivalent Sq current system reasonably well for all seasons. For H component, the first solar harmonic (s1) obtained from spherical harmonic analysis of the data, appeared as the largest harmonic with no significant changes for the seasonal division of data. However, for D and Z components, amplitudes are comparable, but undergo distinct variations. s1 for H and D components increases with magnetic activity while for Z component it is the largest for the medium phase of magnetic activity. With the sunspot number division of data, the weighted mean of the Wolf ratio of all three components is in good agreement with the previous studies. The synthesized solar daily variation for D component, S(D), at Karachi, Sonmiani, Quetta and Islamabad did not show any signs of winter anomaly for the period studied. However, S(D) variation at Karachi during winter season showed morning minimum followed by a maximum at local noon and another minimum in the afternoon. We suggest this could be the effects of Equatorial Ionospheric Anomaly (EIA) observable at the Karachi observatory only during the winter season. Similarly, much disturbed in equinoctial and summer months, S(Z) illustrated an unwavering daily

  20. The ionospheric signature of flux transfer events

    NASA Technical Reports Server (NTRS)

    Cowley, S. W. H.; Freeman, M. P.; Lockwood, Mike; Smith, M. F.

    1991-01-01

    The effects at ionospheric heights which take place when transient reconnection events (i.e., Flux Tranfer Events (FTEs)) occur at the dayside magnetopause are considered. The nature of the FTE related ionospheric flows, the associated current systems, and the plasma precipitation, are discussed. In particular, the nature of the time dependent cusp precipitation which occurs on this case is outlined and expectations are compared with those based on steady magnetopause reconnection.

  1. Tsunamis warning from space :Ionosphere seismology

    SciTech Connect

    Larmat, Carene

    2012-09-04

    Ionosphere is the layer of the atmosphere from about 85 to 600km containing electrons and electrically charged atoms that are produced by solar radiation. Perturbations - layering affected by day and night, X-rays and high-energy protons from the solar flares, geomagnetic storms, lightning, drivers-from-below. Strategic for radio-wave transmission. This project discusses the inversion of ionosphere signals, tsunami wave amplitude and coupling parameters, which improves tsunami warning systems.

  2. Tools for Coordinated Planning Between Observatories

    NASA Technical Reports Server (NTRS)

    Jones, Jeremy; Fishman, Mark; Grella, Vince; Kerbel, Uri; Maks, Lori; Misra, Dharitri; Pell, Vince; Powers, Edward I. (Technical Monitor)

    2001-01-01

    With the realization of NASA's era of great observatories, there are now more than three space-based telescopes operating in different wavebands. This situation provides astronomers with a unique opportunity to simultaneously observe with multiple observatories. Yet scheduling multiple observatories simultaneously is highly inefficient when compared to observations using only one single observatory. Thus, programs using multiple observatories are limited not due to scientific restrictions, but due to operational inefficiencies. At present, multi-observatory programs are conducted by submitting observing proposals separately to each concerned observatory. To assure that the proposed observations can be scheduled, each observatory's staff has to check that the observations are valid and meet all the constraints for their own observatory; in addition, they have to verify that the observations satisfy the constraints of the other observatories. Thus, coordinated observations require painstaking manual collaboration among the observatory staff at each observatory. Due to the lack of automated tools for coordinated observations, this process is time consuming, error-prone, and the outcome of the requests is not certain until the very end. To increase observatory operations efficiency, such manpower intensive processes need to undergo re-engineering. To overcome this critical deficiency, Goddard Space Flight Center's Advanced Architectures and Automation Branch is developing a prototype effort called the Visual Observation Layout Tool (VOLT). The main objective of the VOLT project is to provide visual tools to help automate the planning of coordinated observations by multiple astronomical observatories, as well as to increase the scheduling probability of all observations.

  3. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown.

  4. Airborne ballistic camera tracking systems

    NASA Technical Reports Server (NTRS)

    Redish, W. L.

    1976-01-01

    An operational airborne ballistic camera tracking system was tested for operational and data reduction feasibility. The acquisition and data processing requirements of the system are discussed. Suggestions for future improvements are also noted. A description of the data reduction mathematics is outlined. Results from a successful reentry test mission are tabulated. The test mission indicated that airborne ballistic camera tracking systems are feasible.

  5. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown. PMID:23406937

  6. Ionospheric Response Due to Seismic Activity

    NASA Astrophysics Data System (ADS)

    Sharma, Dinesh Kumar

    2016-07-01

    Signatures of the seismic activity in the ionospheric F2 region have been studied by analyzing the measurement of electron and ion temperatures during the occurrence of earthquake. The ionospheric electron and ion temperatures data recorded by the RPA payload aboard the Indian SROSS-C2 satellite during the period from January 1995 to December 2000 were used for the altitude range 430-630 km over Indian region. The normal day's electron and ion temperatures have been compared to the temperatures recorded during the seismic activity. The details of seismic events were obtained from USGS earthquake data information website. It has been found that the average electron temperature is enhanced during the occurrence of earthquakes by 1.2 to 1.5 times and this enhancement was for ion temperature ranging from 1.1to 1.3 times over the normal day's average temperatures. The above careful quantitative analysis of ionospheric electron and ion temperatures data shows the consistent enhancement in the ionospheric electron and ion temperatures. It is expected that the seismogenic vertical electrical field propagates up to the ionospheric heights and induces Joule heating that may cause the enhancement in ionospheric temperatures.

  7. The lower ionosphere at high latitudes

    NASA Astrophysics Data System (ADS)

    Schunk, R. W.; Sojka, J. J.

    The lower ionosphere is a particularly difficult region to both observe and model. Although radars and rockets have probed this region for more than two decades, our overall understanding of the interplay between radiative, chemical, dynamical, and electrodynamical processes in the lower ionosphere is relatively poor in comparison to the other regions of the solar-terrestrial system. Part of the problem is that the various radar and rocket campaigns have focused on different scientific issues, have been of limited duration, or have been restricted to specific geographical locations. However, the lower ionosphere is a complex region, being acted upon by magnetospheric processes from above and stratospheric processes from below. Within the lower ionosphere are chemical reactions involving negative, positive, and cluster ions; transport processes that sometimes involve ordinary diffusion, turbulence, and wave-particle interactions due to plasma instabilities; radiative processes that could involve multiple scattering effects; and energetics that could result in non-Maxwellian ion velocity distribution functions. A further complication arises in that the processes acting on and within the lower ionosphere do so on widely different spatial and temporal scales, and these scales are directly reproduced in the medium. An overview of our current knowledge of the lower ionosphere is presented in this brief review, with the emphasis on the high latitude region.

  8. Active plasma antenna in the Earth's ionosphere

    NASA Astrophysics Data System (ADS)

    Chugunov, Yu. V.; Markov, G. A.

    2001-11-01

    We discuss a new method for controlled stimulation of global perturbations in the Earth's ionosphere and magnetosphere and new possibilities of diagnostics of the wave-particle interaction in the ionospheric and magnetospheric plasma. The method is based on the excitation of an RF plasma-wave discharge in the electromagnetic field of a rocket-borne dipole antenna in the lower oblique-resonance frequency band. The evolution of the discharge leads to the creation of strong local disturbances at ionospheric altitudes in the form of magnetic-field-aligned plasma irregularities with controllable properties. The method was verified in 6 rocket flights at middle and polar latitudes. We review the results of these experiments, focusing considerable attention on those which show significant plasma disturbances in the magnetic flux tube where the rocket is located and which demonstrate the diversity of capabilities of this method. In particular, it is shown that a deep (by an order of magnitude) modulation of energetic (>=40keV) precipitating electrons is available. We have demonstrated that a modulated discharge in the ionosphere can operate as an active plasma antenna. A generation of ``echo'' signals at the discharge modulation frequency and an excitation of the ionospheric Alfvén resonator in the PC band have also been observed. Along with numerous scientific advantages, the method has appeared to be energy-effective and low-cost, which makes it very promising for ionospheric and magnetospheric studies as well as for various practical applications.

  9. A knowledge-based expert system for scheduling of airborne astronomical observations

    NASA Technical Reports Server (NTRS)

    Nachtsheim, P. R.; Gevarter, W. B.; Stutz, J. C.; Banda, C. P.

    1985-01-01

    The Kuiper Airborne Observatory Scheduler (KAOS) is a knowledge-based expert system developed at NASA Ames Research Center to assist in route planning of a C-141 flying astronomical observatory. This program determines a sequence of flight legs that enables sequential observations of a set of heavenly bodies derived from a list of desirable objects. The possible flight legs are constrained by problems of observability, avoiding flyovers of warning and restricted military zones, and running out of fuel. A significant contribution of the KAOS program is that it couples computational capability with a reasoning system.

  10. Resolving Ionospheric E-region Modeling Challenges: The Solar Photon Flux Dependence

    NASA Astrophysics Data System (ADS)

    Jensen, Joseph; Sojka, Jan; David, Michael; Tobiska, Kent; Schunk, Robert; Woods, Tom; Eparvier, Frank

    2013-04-01

    The EVE instrument of the NASA Solar Dynamics Observatory (SDO) provides for the first time EUV and XUV measurements of the solar irradiance that adequately define the major source of ionization of the atmosphere. In our study we modeled the E-region of the ionosphere and analyzed how it is affected by the solar irradiance data obtained by EVE and contrast this with the S2000 Solar Irradiance model, used previously. The ionosphere has two major layers, the E-layer at 100 km, and the F-layer at 300 km. The difference in solar irradiances are small except at some wavelength bands, it is these differences that lead to a better understanding of the physical/chemical processes of the E-region. Observations of the ionospheric layers is best achieved using incoherent scatter radars (ISR). We have compared our model with ISR data available from Arecibo Puerto Rico in an effort to understand how specific solar irradiance wavelength bands affect the E-region. This study focuses on two specific wavelength bands 0.1-15 nm and 91-103 nm. Both are responsible for E-region production, but in quite different manners.

  11. Challenges Handling Magnetospheric and Ionospheric Signals in Internal Geomagnetic Field Modelling

    NASA Astrophysics Data System (ADS)

    Finlay, C. C.; Lesur, V.; Thébault, E.; Vervelidou, F.; Morschhauser, A.; Shore, R.

    2016-09-01

    Measurements of the Earth's magnetic field collected by low-Earth-orbit satellites such as Swarm and CHAMP, as well as at ground observatories, are dominated by sources in the Earth's interior. However these measurements also contain significant contributions from more rapidly-varying current systems in the ionosphere and magnetosphere. In order to fully exploit magnetic data to probe the physical properties and dynamics of the Earth's interior, field models with suitable treatments of external sources, and their associated induced signals, are essential. Here we review the methods presently used to construct models of the internal field, focusing on techniques to handle magnetospheric and ionospheric signals. Shortcomings of these techniques often limit the quality, as well as spatial and temporal resolution, of internal field models. We document difficulties in using track-by-track analysis to characterize magnetospheric field fluctuations, differences in internal field models that result from alternative treatments of the quiet-time ionospheric field, and challenges associated with rapidly changing, but spatially correlated, magnetic signatures of polar cap current systems. Possible strategies for improving internal field models are discussed, many of which are described in more detail elsewhere in this volume.

  12. The National Ecological Observatory Network

    NASA Astrophysics Data System (ADS)

    Michener, W. K.

    2006-05-01

    The National Ecological Observatory Network (NEON) is a research platform designed to advance understanding of how ecosystems and organisms respond to variations in climate and changes in land use. NEON is the first long-term ecological observatory conceived as a continental-scale network; equipped with standardized sensors, cyberinfrastructure, and data-collection protocols across the network; and designed to simultaneously address a common set of research questions and support investigator-driven ecological research in all regions of the United States. The Observatory focuses on variations in climate and land use because they are primary drivers of the Nation's environmental challenges, as identified by the National Research Council--i.e., biodiversity, biogeochemical cycles, climate change, hydroecology, infectious disease, invasive species, and land use. At the broadest scale, NEON links the complexity of climate variation to the behavior of ecological systems, a core aspect of ecological complexity. At the same time, because of the complexity of the interactions among humans and ecosystems, the network design includes NEON sites in wild, managed and urban systems within climate domains. Observatory data will also be part of a national education program designed to advance ecological science literacy through new programs and activities that develop and promote scientific ways of thinking.

  13. Planetary research at Lowell Observatory

    NASA Technical Reports Server (NTRS)

    Baum, William A.

    1988-01-01

    Scientific goals include a better determination of the basic physical characteristics of cometary nuclei, a more complete understanding of the complex processes in the comae, a survey of abundances and gas/dust ratios in a large number of comets, and measurement of primordial (12)C/(13)C and (14)N/(15)N ratios. The program also includes the observation of Pluto-Charon mutual eclipses to derive dimensions. Reduction and analysis of extensive narrowband photometry of Comet Halley from Cerro Tololo Inter-American Observatory, Perth Observatory, Lowell Observatory, and Mauna Kea Observatory were completed. It was shown that the 7.4-day periodicity in the activity of Comet Halley was present from late February through at least early June 1986, but there is no conclusive evidence of periodic variability in the preperihelion data. Greatly improved NH scalelengths and lifetimes were derived from the Halley data which lead to the conclusion that the abundance of NH in comets is much higher than previously believed. Simultaneous optical and thermal infrared observations were obtained of Comet P/Temple 2 using the MKO 2.2 m telescope and the NASA IRTF. Preliminary analysis of these observations shows that the comet's nucleus is highly elongated, very dark, and quite red.

  14. The Coronal Solar Magnetism Observatory

    NASA Astrophysics Data System (ADS)

    Tomczyk, S.; Landi, E.; Zhang, J.; Lin, H.; DeLuca, E. E.

    2015-12-01

    Measurements of coronal and chromospheric magnetic fields are arguably the most important observables required for advances in our understanding of the processes responsible for coronal heating, coronal dynamics and the generation of space weather that affects communications, GPS systems, space flight, and power transmission. The Coronal Solar Magnetism Observatory (COSMO) is a proposed ground-based suite of instruments designed for routine study of coronal and chromospheric magnetic fields and their environment, and to understand the formation of coronal mass ejections (CME) and their relation to other forms of solar activity. This new facility will be operated by the High Altitude Observatory of the National Center for Atmospheric Research (HAO/NCAR) with partners at the University of Michigan, the University of Hawaii and George Mason University in support of the solar and heliospheric community. It will replace the current NCAR Mauna Loa Solar Observatory (http://mlso.hao.ucar.edu). COSMO will enhance the value of existing and new observatories on the ground and in space by providing unique and crucial observations of the global coronal and chromospheric magnetic field and its evolution. The design and current status of the COSMO will be reviewed.

  15. ISS images for Observatory protection

    NASA Astrophysics Data System (ADS)

    Sánchez de Miguel, Alejandro; Zamorano, Jaime

    2015-08-01

    Light pollution is the main factor of degradation of the astronomical quality of the sky along the history. Astronomical observatories have been monitoring how the brightness of the sky varies using photometric measures of the night sky brightness mainly at zenith. Since the sky brightness depends in other factors such as sky glow, aerosols, solar activity and the presence of celestial objects, the continuous increase of light pollution in these enclaves is difficult to trace except when it is too late.Using models of light dispersion on the atmosphere one can determine which light pollution sources are increasing the sky brightness at the observatories. The input satellite data has been provided by DMSP/OLS and SNPP/VIIRS. Unfortunately their panchromatic bands (color blinded) are not useful to detect in which extension the increase is due to the dramatic change produced by the irruption of LED technology in outdoor lighting. The only instrument in the space that is able to distinguish between the various lighting technologies are the DSLR cameras used by the astronauts onboard the ISS.Current status for some astronomical observatories that have been imaged from the ISS is presented. We are planning to send an official request to NASA with a plan to get images for the most important astronomical observatories. We ask support for this proposal by the astronomical community and especially by the US-based researchers.

  16. The gamma-ray observatory

    NASA Technical Reports Server (NTRS)

    1991-01-01

    An overview is given of the Gamma Ray Observatory (GRO) mission. Detection of gamma rays and gamma ray sources, operations using the Space Shuttle, and instruments aboard the GRO, including the Burst and Transient Source Experiment (BATSE), the Oriented Scintillation Spectrometer Experiment (OSSE), the Imaging Compton Telescope (COMPTEL), and the Energetic Gamma Ray Experiment Telescope (EGRET) are among the topics surveyed.

  17. Testing Ionospheric Faraday Rotation Corrections in CASA

    NASA Astrophysics Data System (ADS)

    Kooi, Jason E.; Moellenbrock, George

    2015-04-01

    The Earth’s ionosphere introduces direction- and time-dependent effects over a range of physical and temporal scales and so is a major source for unmodeled phase offsets for low frequency radioastronomical observations. Ionospheric effects are often the limiting factor to making sensitive radioastronomical measurements to probe the solar corona or coronal mass ejections at low frequencies (< 5 GHz). It has become common practice to use global ionospheric models derived from the Global Positioning System (GPS) to provide a means of externally calibrating low frequency data. We have developed a new calibration algorithm in the Common Astronomy Software Applications (CASA) package. CASA, which was developed to meet the data post-processing needs of next generation telescopes such as the Karl G. Jansky Very Large Array (VLA), did not previously have the capability to mitigate ionospheric effects. This algorithm uses GPS-based global ionosphere maps to mitigate the first and second order ionospheric effects (dispersion delay and Faraday rotation, respectively). We investigated several data centers as potential sources for global ionospheric models and chose the International Global Navigation Satellite System Service data product because data from other sources are generally too sparse to use without additional interpolation schemes. This implementation of ionospheric corrections in CASA has been tested on several sets of VLA observations and all of them showed a significant reduction of the dispersion delay. In order to rigorously test CASA’s ability to mitigate ionospheric Faraday rotation, we made VLA full-polarization observations of the standard VLA phase calibrators J0359+5057 and J0423+4150 in August 2014, using L band (1 - 2 GHz), S band (2 - 4 GHz), and C band (4 - 6 GHz) frequencies in the D array configuration. The observations were 4 hours in duration, beginning near local sunrise. In this paper, we give a general description of how these corrections are

  18. Norwegian Ocean Observatory Network (NOON)

    NASA Astrophysics Data System (ADS)

    Ferré, Bénédicte; Mienert, Jürgen; Winther, Svein; Hageberg, Anne; Rune Godoe, Olav; Partners, Noon

    2010-05-01

    The Norwegian Ocean Observatory Network (NOON) is led by the University of Tromsø and collaborates with the Universities of Oslo and Bergen, UniResearch, Institute of Marine Research, Christian Michelsen Research and SINTEF. It is supported by the Research Council of Norway and oil and gas (O&G) industries like Statoil to develop science, technology and new educational programs. Main topics relate to ocean climate and environment as well as marine resources offshore Norway from the northern North Atlantic to the Arctic Ocean. NOON's vision is to bring Norway to the international forefront in using cable based ocean observatory technology for marine science and management, by establishing an infrastructure that enables real-time and long term monitoring of processes and interactions between hydrosphere, geosphere and biosphere. This activity is in concert with the EU funded European Strategy Forum on Research Infrastructures (ESFRI) roadmap and European Multidisciplinary Seafloor Observation (EMSO) project to attract international leading research developments. NOON envisions developing towards a European Research Infrastructure Consortium (ERIC). Beside, the research community in Norway already possesses a considerable marine infrastructure that can expand towards an international focus for real-time multidisciplinary observations in times of rapid climate change. PIC The presently established cable-based fjord observatory, followed by the establishment of a cable-based ocean observatory network towards the Arctic from an O&G installation, will provide invaluable knowledge and experience necessary to make a successful larger cable-based observatory network at the Norwegian and Arctic margin (figure 1). Access to large quantities of real-time observation from the deep sea, including high definition video, could be used to provide the public and future recruits to science a fascinating insight into an almost unexplored part of the Earth beyond the Arctic Circle

  19. Space Weather Studies Using the Low-Latitude Ionospheric Sensor Network (LISN)

    NASA Astrophysics Data System (ADS)

    Valladares, C. E.; Pacheco, E.

    2014-12-01

    LISN is an array of small instruments that operates as a real-time distributed observatory to understand the complex day-to-day variability and the extreme state of disturbance that occurs in the South American low-latitude ionosphere nearly every day after sunset. The LISN observatory aims to forecast the initiation and transport of plasma bubbles across the South American continent. The occurrence of this type of plasma structures and their embedded irregularities poses a prominent natural hazard to communication, navigation and high precision pointing systems. As commercial and military aviation is increasingly reliant on Global Navigation Satellite Systems (GNSS) any interruption due to ionospheric irregularities or errors due to large density gradients constitutes a serious threat to passengers and crew. Therefore, it is important to understand the conditions and sources that contribute to the formation of these irregularities. To achieve high quality regional nowcasts and forecasts, the LISN system was designed to include a dense coverage of the South American landmass with 47 GPS receivers, 5 flux-gate magnetometers distributed on 2 base lines and 3 Vertical Incidence Pulsed Ionospheric Radar (VIPIR) ionosondes deployed along the same magnetic meridian that intersects the magnetic equator at 68° W. This presentation will provide a summary of recent instrument installations and new processing techniques that have been developed under the LISN project. We will also present the results of recent efforts to detect TIDs and TEC plasma depletions on a near real-time basis. We will describe a method to estimate the zonal velocity and tilt of the plasma bubbles/depletions by combining observations of TEC depletions acquired with adjacent receivers, making it possible to predict precisely their future locations.

  20. A Comprehensive Assessment of Radio Occultation Ionospheric Measurements at Mid-Latitudes

    NASA Astrophysics Data System (ADS)

    Keele, C.; Brum, C. G. M.; Rodrigues, F. S.; Aponte, N.; Sulzer, M. P.

    2015-12-01

    The GPS radio occultation (RO) has become a widely used technique for global measurements of the ionospheric electron density (Ne). To advance our understanding of the accuracy of the RO profiles at mid latitudes, we performed a comprehensive comparison of RO measurements made by the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites and observations of Ne profiles made by the Arecibo Observatory incoherent scatter radar (ISR). COSMIC is formed by six satellites in circular, 800 km altitude low-Earth orbit (LEO) at 72° inclination. The satellites orbit in their own plane, approximately 24° apart in ascending node. The satellites are equipped with dual-frequency GPS receivers capable of making measurements of the total electron content (TEC) along the signal path and, therefore, RO observations. The Arecibo ISR, located at(18.35°N, 66.75°W; ˜28.25°N dip latitude), operates at a frequency of 430 MHz with a maximum bandwidth of about 1 MHz. The large collecting area provided by the 300 m dish antenna combined with high peak power transmitters (2.0-2.5 MW) allows the radar to make accurate Ne measurements throughout the entire ionospheric F-region and topside heights. We analyzed 74 and 89 days of line feed and Gregorian data, respectively, collected between 2006 and 2014. There were 638 RO profiles measured within 10° of latitude and 20° of longitude from Arecibo Observatory and within ±10 minutes of the radar measurements. Preliminary analyses of the observations show patterns in the relationship between densities measured by the Arecibo ISR and densities estimated from the COSMIC ROs. We will present and discuss the behavior of the patterns. We will also present results of a numerical model representing the patterns and discuss the possibility of using this model to improve RO estimates of density profiles.

  1. Post-flare effects in the lower ionosphere of middle latitudes

    NASA Technical Reports Server (NTRS)

    Krivsky, L.

    1989-01-01

    Beginning in the 1960s, records were made of noise from the region around the Polar Star on 29 MHz (Krivsky and Tlamicha, 1960) at the Ondrejov Observatory near Prague. Since the aerial characteristic was not too narrow, radio bursts were received of solar origin (of flares) at the noise level, SCNA effects (sudden cosmic noise absorption) at the time of intensive flare X-emission and in some rare cases, after large proton flares, small absorption effects of a few hours duration (Krivsky, 1969). These post-flare absorption effects in cosmic noise are evidently analogous with PCA effects (polar cap absorption) and are connected with ionospheric absorption of radio cosmic noise, caused by fast particles of subcosmic radiation. The recording of long term absorption effects after large particle flares at European midlatitudes was reported at the beginning of the 1960s. It was then usual to record radio cosmic noise with riometers at frequencies of about 18 MHz in the polar or subpolar regions in an effort to record PCA effects of subcosmic radiation (Hakura, 1968). An attempt was made to record the complex of emissions mentioned as well as the effects in a new frequency range (30 MHz), which did not agree with the ideas of the contemporaneous representatives of the Ionospheric Department of the Geophysical Institute in Prague. In recent years radio cosmic noise has been recorded at the Upice Observatory. These long term after flare effects of cosmic radio noise absorption (AF-CNA) at middle latitudes are reported to the geophysical and ionospheric community for the first time.

  2. Bistatic Sounding of High-Latitude Ionospheric Irregularities Using a Decameter EKB Radar and an UTR-2 Radio Telescope: First Results

    NASA Astrophysics Data System (ADS)

    Berngardt, O. I.; Kutelev, K. A.; Kurkin, V. I.; Grkovich, K. V.; Yampolsky, Yu. M.; Kashcheyev, A. S.; Kashcheyev, S. B.; Galushko, V. G.; Grigorieva, S. A.; Kusonsky, O. A.

    2015-11-01

    We present the first results of the joint Russian-Ukrainian experiments for recording of signals from the EKB radar of the Institute of Solar-Terrestrial Physics of the Siberian Branch of the Russian Academy of Sciences (Arti observatory of the Institute of Geophysics of the Ural Branch of the Russian Academy of Sciences, Sverdlovsk region, Russia) at a distance of over 1600 km by using a coherent receiving system and a high-gain phased array of the UTR-2 radio telescope (S.Ya. Braude Radioastronomical Observatory (RAO) of the Institute of Radio Astronomy of the Ukrainian National Academy of Sciences (IRA UNAS), Kharkov region, Ukraine). It is shown that two pulse sequences that are identical to the transmitted EKB radar signal, but arrive with different delays were observed at the reception point. The sequence which was received first corresponded to the direct-signal propagation along the great-circle arc. The second sequence was received with delays corresponding to a path length of 2800 to 3400 km and was the result of scattering of the transmitted radar signal by high-latitude ionospheric irregularities. The Doppler frequency shift of the scattered signal was range-dependent and varied from -3 to +4 Hz, which corresponded to the radial component of the ionospheric irregularity velocity from -43 to +58 m/s. To interpret the results of the experiments, we numerically simulated the signal propagation based on the actual ionospheric conditions at an appropriate time. Ionospheric characteristics were retrieved by the vertical ionospheric sounding technique, with the ionosonde located in close proximity to the EKB radar. Comparison between monostatic radar diagnostic results and bistatic sounding results has shown a good agreement of the retrieved parameters of the high-latitude ionospheric irregularities.

  3. Modeling for Airborne Contamination

    SciTech Connect

    F.R. Faillace; Y. Yuan

    2000-08-31

    The objective of Modeling for Airborne Contamination (referred to from now on as ''this report'') is to provide a documented methodology, along with supporting information, for estimating the release, transport, and assessment of dose to workers from airborne radioactive contaminants within the Monitored Geologic Repository (MGR) subsurface during the pre-closure period. Specifically, this report provides engineers and scientists with methodologies for estimating how concentrations of contaminants might be distributed in the air and on the drift surfaces if released from waste packages inside the repository. This report also provides dose conversion factors for inhalation, air submersion, and ground exposure pathways used to derive doses to potentially exposed subsurface workers. The scope of this report is limited to radiological contaminants (particulate, volatile and gaseous) resulting from waste package leaks (if any) and surface contamination and their transport processes. Neutron activation of air, dust in the air and the rock walls of the drift during the preclosure time is not considered within the scope of this report. Any neutrons causing such activation are not themselves considered to be ''contaminants'' released from the waste package. This report: (1) Documents mathematical models and model parameters for evaluating airborne contaminant transport within the MGR subsurface; and (2) Provides tables of dose conversion factors for inhalation, air submersion, and ground exposure pathways for important radionuclides. The dose conversion factors for air submersion and ground exposure pathways are further limited to drift diameters of 7.62 m and 5.5 m, corresponding to the main and emplacement drifts, respectively. If the final repository design significantly deviates from these drift dimensions, the results in this report may require revision. The dose conversion factors are further derived by using concrete of sufficient thickness to simulate the drift

  4. Education partnerships at 41,000 feet: The stratospheric Observatory for Infrared Astronomy (SOFIA) education and outreach program

    NASA Astrophysics Data System (ADS)

    Devore, Edna

    The SOFIA Education and Public Outreach Program (E/PO) is under development as this unique astronomical observatory is being designed and constructed. SOFIA is an infrared astronomical observatory comprised of a 2.5-meter telescope mounted in a Boeing 747SP aircraft. By flying above the water vapor in Earth's atmosphere, SOFIA will observe the infrared universe, studying the birth place of stars, the formation of planets, and the ecology of galaxies. SOFIA is also the world's largest portable telescope, and will be used to observe events such as occultations that require the observatory be at a particular location on Earth. As an airborne observatory, SOFIA is accessible during research flights; SOFIA will carry on board a compliment of pilots, scientists and their graduate students, observatory staff, and visiting educators, members of the press, and other guests. Unique in the world of major observatories, SOFIA is being designed and constructed to accommodate guests during the research process. Educators (teachers, college faculty, planetarium and museum staff, and others) will have the opportunity to partner with scientists as a part of the E/PO program for SOFIA. Participants will be selected to offer broad participation. Training will be provided, and participants will be supported beyond the immediate research flight experience as a network of Airborne Astronomy Ambassadors (AAA) in their schools, science centers, and communities. Other EPO activities include partnerships between scientists and educators at universities and research laboratories, internships and fellowships (1-2 years in duration) at the observatory. Research missions begin in late 2004 with AAA participation expected in 2005. SOFIA will be operated for NASA by Universities Space Research Association (USRA) with the USRA-led team: University of California, L3 Communications, United Airlines, Astronomical Society of the Pacific and the SETI Institute. SOFIA is a joint US-German project funded

  5. The variations of ionosphere critical frequency of E layer over the equatorial geomagnetic region in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Kenpankho, Prasert; Ishii, Mamoru; Supnithi, Pornchai

    2016-07-01

    We investigate the values of the critical frequency of the ionospheric E layer, foE, obtained at Chumphon ionospheric observatory station, Thailand. For a declining phase of the solar cycle 23 during the year 2005-2008 and an inclining phase of the solar cycle 24 during the year 2009-2013, the foE data have been used to investigate the foE variations over the equatorial geomagnetic region in Southeast Asia. A comparison between the observation data and International Reference Ionosphere (IRI) 2012 model has also been investigated and studied. The results show that the foE obtained from IRI 2012 model underestimates foE from Chumphon station especially during the period of 7-11 am and after 6 pm for each day and all seasons. As the results combining with the previous investigations, we suggest that the underestimation of ionospheric foE by IRI 2012 model is helpful for the correction and improvement of IRI model in an equatorial Asia region.

  6. SOFIA - Stratospheric Observatory for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Kunz, Nans; Bowers, Al

    2007-01-01

    This viewgraph presentation reviews the Stratospheric Observatory for Infrared Astronomy (SOFIA). The contents include: 1) Heritage & History; 2) Level 1 Requirements; 3) Top Level Overview of the Observatory; 4) Development Challenges; and 5) Highlight Photos.

  7. SOFIA: Stratospheric Observatory for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Becker, Eric; Kunz, Nans; Bowers, Al

    2007-01-01

    This viewgraph presentation reviews the Stratospheric Observatory for Infrared Astronomy (SOFIA). The contents include: 1) Heritage & History; 2) Level 1 Requirements; 3) Top Level Overview of the Observatory; 4) Development Challenges; and 5) Highlight Photos.

  8. Ionospheric Variability and Storms on Mars

    NASA Technical Reports Server (NTRS)

    Mendillo, Michael

    2004-01-01

    The goal of this grant was to conduct the first-ever study of ionospheric variability on Mars. To do so, we used data from the Radio Science (RS) experiment onboard the Mars Global Surveyor (MGS) satellite. Dr. David Hinson of the RS team at Stanford University was a most helpful and valuable colleague throughout the studies we conducted. For the initial RS datasets available from the MGS mission, there were no severe storms caused by solar wind activity, so we concentrated on day-to-day effects. This turned out to be a wise approach since understanding "normal variability" had to be done before any claim could be made about "space weather" effects. Our approach was three-fold: (1) select a good dataset for characterization of ionosphere variability at Mars, one for which excellent terrestrial data were also available. This turned out to be the period 9-27 March 1999; (2) once the variability at Mars was described, develop and use a new photochemical model of the martian ionosphere to find the extent to which solar variability on those days caused or contributed to the observed patterns; (3) use the results from the above, together with additional datasets from the MGS/RS experiment, to describe some practical consequences that the martian ionosphere would have upon NASA s proposed navigation and communications systems for Mars. The results of these studies showed that: (a) solar variability is the dominant source of ionospheric variability at Mars (during periods of quiet solar wind), (b) that current models do a good job in portraying such effects at the height of the ionospheric peak electron density, and (c) that ionospheric structure on Mars can affect attempts at precise position-fixing at Mars should relatively high (GPS-like) frequencies not be used in a Mars communications and navigation system.

  9. Ionospheric Storms in Equatorial Region: Digisonde Observations

    NASA Astrophysics Data System (ADS)

    Paznukhov, V.; Altadill, D.; Blanch, E.

    2011-12-01

    We present a study of the ionospheric storms observed in the low-latitude and equatorial ionosphere at several digisonde stations: Jicamarca (Geomagnetic Coordinates: 2.0 S, 355.3 E), Kwajalein Island (3.8 N, 238.2 E), Ascension Island (2.5 S, 56.8 E), Fortaleza (4.8 N, 33.7 W), and Ramey (28.6 N, 5.2 E). The strongest geomagnetic storms from years 1995-2009 have been analyzed. The main ionospheric characteristics, hmF2 and foF2 were used in the study, making it possible to investigate the changes in the ionosphere peak density and height during the storms. All digisonde data were manually processed to assure the accuracy of the measurements. Solar wind data, geomagnetic field variations, and auroral activity indices have been used to characterize the geomagnetic environment during the events. It was found in our analysis that the major drivers for the ionospheric storms, electric field and neutral wind have approximately equal importance at the low-latitude and equatorial latitudes. This is noticeably different from the behavior of the ionsphere in the middle latitudes, where the neutral wind is usually a dominant factor. It was found that the auroral index, AE is the best precursor of the ionospheric effects observed during the storms in this region. We analyze the difference between time delays of the storm effects observed at the stations located in different local time sectors. The overall statistics of the time delays of the storms as a function of the local time at the stations is also presented. Several very interesting cases of sudden very strong ionospheric uplifting and their possible relation to the equatorial super fountain effect are investigated in greater details.

  10. Role of Ionospheric Plasmas in Earth's Magnetotail

    NASA Technical Reports Server (NTRS)

    Moore, Thomas E.

    2007-01-01

    This tutorial will summarize observations and theories indicating a prominent role of ionospheric plasma in the Earth's magnetotail. At the Global scale, I will argue that it is ionospheric plasma momentum and dynamic pressure that are responsible for the production of plasmoids, through the action of a transient near-Earth neutral or X-line, which serves to release excessive plasma pressure from the magnetotail field. Ionospheric plasma gains the momentum and energy to produce plasmoids and their related effects through its interaction with the solar wind, beginning at the dayside reconnection region and extending across the polar caps through the magnetotail lobes. This distant neutral line can be depicted as a feature much like that found in cometary magnetospheres, where disconnection limits the amount of IMF hung up on the cometary coma. On the other hand, the near-Earth neutral one can be seen as a feature unique to planets with an intrinsic magnetic field and internal source of plasma, the heating of which produces pressures too large to be restrained. Ionospheric plasmas also have other more local roles to play in the magnetotail. The circulation influences the composition of the plasma sheet, and the resultant wave environment, giving rise to reduced wave propagation speeds. Important heavy ion cyclotron resonances, and enhanced finite gyro-radius effects including non-adiabatic particle acceleration. At minimum, the presence of ionospheric plasma must influence the rate of reconnection via its enhanced mass density. Other non-MHD effects of ionospheric plasma presence are likely to be important but need much more investigation to be well understood. The MMS mission is designed to penetrate the subtle diffusion region physics that is involved, and its ability to observe ionospheric plasma involvement in reconnection will contribute significantly toward that goal.

  11. Continuous day-time time series of E-region equatorial electric fields derived from ground magnetic observatory data

    NASA Astrophysics Data System (ADS)

    Alken, P.; Chulliat, A.; Maus, S.

    2012-12-01

    The day-time eastward equatorial electric field (EEF) in the ionospheric E-region plays an important role in equatorial ionospheric dynamics. It is responsible for driving the equatorial electrojet (EEJ) current system, equatorial vertical ion drifts, and the equatorial ionization anomaly (EIA). Due to its importance, there is much interest in accurately measuring and modeling the EEF. However, there are limited sources of direct EEF measurements with full temporal and spatial coverage of the equatorial ionosphere. In this work, we propose a method of estimating a continuous day-time time series of the EEF at any longitude, provided there is a pair of ground magnetic observatories in the region which can accurately track changes in the strength of the EEJ. First, we derive a climatological unit latitudinal current profile from direct overflights of the CHAMP satellite and use delta H measurements from the ground observatory pair to determine the magnitude of the current. The time series of current profiles is then inverted for the EEF by solving the governing electrodynamic equations. While this method has previously been applied and validated in the Peruvian sector, in this work we demonstrate the method using a pair of magnetometers in Africa (Samogossoni, SAM, 0.18 degrees magnetic latitude and Tamanrasset, TAM, 11.5 degrees magnetic latitude) and validate the resulting EEF values against the CINDI ion velocity meter (IVM) instrument on the C/NOFS satellite. We find a very good 80% correlation with C/NOFS IVM measurements and a root-mean-square difference of 9 m/s in vertical drift velocity. This technique can be extended to any pair of ground observatories which can capture the day-time strength of the EEJ. We plan to apply this work to more observatory pairs around the globe and distribute real-time equatorial electric field values to the community.

  12. Airborne agent concentration analysis

    DOEpatents

    Gelbard, Fred

    2004-02-03

    A method and system for inferring airborne contaminant concentrations in rooms without contaminant sensors, based on data collected by contaminant sensors in other rooms of a building, using known airflow interconnectivity data. The method solves a least squares problem that minimizes the difference between measured and predicted contaminant sensor concentrations with respect to an unknown contaminant release time. Solutions are constrained to providing non-negative initial contaminant concentrations in all rooms. The method can be used to identify a near-optimal distribution of sensors within the building, when then number of available sensors is less than the total number of rooms. This is achieved by having a system-sensor matrix that is non-singular, and by selecting that distribution which yields the lowest condition number of all the distributions considered. The method can predict one or more contaminant initial release points from the collected data.

  13. Airborne Wind Turbine

    SciTech Connect

    2010-09-01

    Broad Funding Opportunity Announcement Project: Makani Power is developing an Airborne Wind Turbine (AWT) that eliminates 90% of the mass of a conventional wind turbine and accesses a stronger, more consistent wind at altitudes of near 1,000 feet. At these altitudes, 85% of the country can offer viable wind resources compared to only 15% accessible with current technology. Additionally, the Makani Power wing can be economically deployed in deep offshore waters, opening up a resource which is 4 times greater than the entire U.S. electrical generation capacity. Makani Power has demonstrated the core technology, including autonomous launch, land, and power generation with an 8 meter wingspan, 20 kW prototype. At commercial scale, Makani Power aims to develop a 600 kW, 28 meter wingspan product capable of delivering energy at an unsubsidized cost competitive with coal, the current benchmark for low-cost power.

  14. The Magnetic Observatory Buildings at the Royal Observatory, Cape

    NASA Astrophysics Data System (ADS)

    Glass, I. S.

    2015-10-01

    During the 1830s there arose a strong international movement, promoted by Carl Friedrich Gauss and Alexander von Humboldt, to characterise the earth's magnetic field. By 1839 the Royal Society in London, driven by Edward Sabine, had organised a "Magnetic Crusade" - the establishment of a series of magnetic and meteorological observatories around the British Empire, including New Zealand, Australia, St Helena and the Cape. This article outlines the history of the latter installation, its buildings and what became of them.

  15. Airborne Cloud Computing Environment (ACCE)

    NASA Technical Reports Server (NTRS)

    Hardman, Sean; Freeborn, Dana; Crichton, Dan; Law, Emily; Kay-Im, Liz

    2011-01-01

    Airborne Cloud Computing Environment (ACCE) is JPL's internal investment to improve the return on airborne missions. Improve development performance of the data system. Improve return on the captured science data. The investment is to develop a common science data system capability for airborne instruments that encompasses the end-to-end lifecycle covering planning, provisioning of data system capabilities, and support for scientific analysis in order to improve the quality, cost effectiveness, and capabilities to enable new scientific discovery and research in earth observation.

  16. A New Polar Magnetic Index of Geomagnetic Activity and its Application to Monitoring Ionospheric Parameters

    NASA Technical Reports Server (NTRS)

    Lyatsky, Wladislaw; Khazanov, George V.

    2008-01-01

    For improving the reliability of Space Weather prediction, we developed a new, Polar Magnetic (PM) index of geomagnetic activity, which shows high correlation with both upstream solar wind data and related events in the magnetosphere and ionosphere. Similarly to the existing polar cap PC index, the new, PM index was computed from data from two near-pole geomagnetic observatories; however, the method for computing the PM index is different. The high correlation of the PM index with both solar wind data and events in Geospace environment makes possible to improve significantly forecasting geomagnetic disturbances and such important parameters as the cross-polar-cap voltage and global Joule heating in high latitude ionosphere, which play an important role in the development of geomagnetic, ionospheric and thermospheric disturbances. We tested the PM index for 10-year period (1995-2004). The correlation between PM index and upstream solar wind data for these years is very high (the average correlation coefficient R approximately equal to 0.86). The PM index also shows the high correlation with the cross-polar-cap voltage and hemispheric Joule heating (the correlation coefficient between the actual and predicted values of these parameters is approximately 0.9), which results in significant increasing the prediction reliability of these parameters. Using the PM index of geomagnetic activity provides a significant increase in the forecasting reliability of geomagnetic disturbances and related events in Geospace environment. The PM index may be also used as an important input parameter in modeling ionospheric, magnetospheric, and thermospheric processes.

  17. Determination of ITM Key Parameters By the Ionospheric Connection Explorer (ICON)

    NASA Astrophysics Data System (ADS)

    Immel, T. J.; England, S.; Mende, S. B.; Makela, J. J.; Harding, B. J.; Stephan, A. W.; Kamalabadi, F.; Heelis, R. A.; Englert, C. R.; Edelstein, J.; Forbes, J. M.; Maute, A. I.; Crowley, G.; Huba, J. D.; Harlander, J.; Swenson, G. R.; Frey, H. U.; Bust, G. S.; Gerard, J. C. M. C.; Hubert, B. A.; Rowland, D. E.; Hysell, D. L.; Saito, A.; Frey, S.; Bester, M.; Craig, W.

    2014-12-01

    Selected for development by NASA in 2013, ICON is a mission that will launch in 2017 to discover the source of strong day-to-day variability in Earth's space environment. Recent observations continue to raise questions about the effects and interaction of these in our geospace environment, and how these vary between extremes in solar activity. To address these, ICON will measure all key parameters of the atmosphere and ionosphere simultaneously and continuously with a combination of remote sensing and in-situ measurements. ICON will fly in a 27-degree inclination orbit with a payload designed to observe the processes of vertical wave coupling in the Ionosphere/Thermosphere/Mesosphere system, how these processes influence the state of the system itself, and how that state preconditions the system for modification by external influence (e.g. solar and solar wind forcing). ICON will remotely observe winds and temperatures in the 90-150 km region while measuring the highly variable electric field in the ionosphere on magnetically connected field lines. Simultaneous to these observations, ICON remotely observes the thermospheric composition and density, and ionospheric density in day and night. The retrievals involved and resultant precision in the determination of key parameters will be presented. The scientific return from ICON is enhanced by dynamic operational modes of the observatory that provide capabilities well beyond that afforded by a static space platform. Careful selection of these modes and the selective implementation of instrument redundancy provide the ability to operate with large technical margins that support the greatest return of science data.

  18. A statistical study of GPS loss of lock caused by ionospheric disturbances

    NASA Astrophysics Data System (ADS)

    Tsugawa, T.; Nishioka, M.; Otsuka, Y.; Saito, A.; Kato, H.; Kubota, M.; Nagatsuma, T.; Murata, K. T.

    2010-12-01

    Two-dimensional total electron content (TEC) maps have been derived from ground-based GPS receiver networks and applied to studies of various ionospheric disturbances since mid-1990s. For the purpose of monitoring and researching ionospheric disturbances which can degrade GNSS navigations and cause loss-of-lock on GNSS signals, National Institute of Information and Communications Technology (NICT), Japan has developed TEC maps over Japan using the dense GPS network, GEONET, which consists of more than 1,200 GPS receivers and is operated by Geophysical Survey Institute, Japan. Currently, we are providing two-dimensional maps of absolute TEC, detrended TEC with 60, 30, 15-minute window, rate of TEC change index (ROTI), and loss-of-lock (LOL) on GPS signal over Japan. These data and quick-look maps since 1997 are archived and available in the website of NICT (http://wdc.nict.go.jp/IONO/). Recently developed GPS receiver networks in North America and Europe make it possible to obtain regional TEC maps with higher spatial and temporal resolution than the global weighted mean TEC maps in the IONEX format provided by several institutes such as International GNSS Service (IGS) and another global TEC map provided by MIT Haystack observatory. Recently, we have also developed the regional TEC maps over North America and Europe. These data and quick-look maps are also available in the NICT website. In this presentation, we will show some severe ionospheric events such as high latitude storm-time plasma bubbles and storm enhanced density events observed over Japan using the GPS-TEC database. These events cause loss-of-lock of GPS signals and large GPS positioning errors. We also discuss about the statistical characteristics of LOL on the GPS signal caused by ionospheric disturbances.

  19. Astronomical observatory for shuttle. Phase A study

    NASA Technical Reports Server (NTRS)

    Guthals, D. L.

    1973-01-01

    The design, development, and configuration of the astronomical observatory for shuttle are discussed. The characteristics of the one meter telescope in the spaceborne observatory are described. A variety of basic spectroscopic and image recording instruments and detectors which will permit a large variety of astronomical observations are reported. The stDC 37485elines which defined the components of the observatory are outlined.

  20. First Thermospheric Winds and Neutral Temperatures statistics Over Oukaimeden Observatory

    NASA Astrophysics Data System (ADS)

    Kaab, Mohamed; Benkhaldoun, Zouhair; Fisher, Daniel J.; Harding, Brian; Makela, Jonathan J.; Bounhir, Aziza; Lazrek, Mohamed; Lagheryeb, Amine; Daassou, Ahmed; Khalifa, Malki

    2015-08-01

    In order to study the thermospheric-ionospheric coupling and to gain a better understanding of thermospheric neutral winds and temperatures by providing measurements over the African sector, we have deployed a new suite of instruments in Morocco: a high-resolution Fabry-Perot interferometer (FPI) and a wide-angle ionospheric imaging system. In this work, we present the statistical results from the first year of observation of thermospheric winds and neutral temperatures made at Oukaimeden Observatory, located 75 km south of Marrakesh 7° 51' W / 31° 12' N. The available data is based on the FPI measurements of Doppler shift and Doppler broadening of the 630.0-nm spectral emission caused by the dissociative recombination of O2+. Viewing the profile of trends of the winds and neutral temperatures shows that the zonal winds are eastward in the early night just after sunset with a speed of 50 m.s-1 up to 150 m.s-1, reducing over the course of the night and switching to westward flow before sunrise. The meridional winds tend to move towards the equator in the summer with speeds exceeding 150 m.s-1, while in the winter they tend to move towards the north pole with a relatively low speed that does not exceed 50 m.s-1. The neutral temperatures show a maximum around ˜1100 K at the beginning of the night and decrease as the night continues until reaching minimum values of ˜700 K before sunrise. The 630.0 nm emission intensity was relatively dim during most of the year, with the exception of a few days in late January and early February when there was a significant increase in the emission's brightness. In this paper, we discuss the instrumentation as well as the variability of these parameters day-to-day, monthly, and seasonally.

  1. Ionospheric Scintillation Effects on GPS

    NASA Astrophysics Data System (ADS)

    Steenburgh, R. A.; Smithtro, C.; Groves, K.

    2007-12-01

    . Ionospheric scintillation of Global Positioning System (GPS) signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active, although not limited to, a belt encircling the earth within 20 degrees of the geomagnetic equator. As GPS applications and users increases, so does the potential for detrimental impacts from scintillation. We examined amplitude scintillation data spanning seven years from Ascension Island, U.K.; Ancon, Peru; and Antofagasta, Chile in the Atlantic/Americas longitudinal sector at as well as data from Parepare, Indonesia; Marak Parak, Malaysia; Pontianak, Indonesia; Guam; and Diego Garcia, U.K.; in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at one minute resolution. We examine diurnal, seasonal and solar cycle characteristics and make spatial comparisons. In general, activity was greatest during the equinoxes and solar maximum, although scintillation at Antofagasta, Chile was higher during 1998 rather than at solar maximum.

  2. Electric fields in the ionosphere

    NASA Technical Reports Server (NTRS)

    Kirchhoff, V. W. J. H.

    1975-01-01

    F-region drift velocities, measured by incoherent-scatter radar were analyzed in terms of diurnal, seasonal, magnetic activity, and solar cycle effects. A comprehensive electric field model was developed that includes the effects of the E and F-region dynamos, magnetospheric sources, and ionospheric conductivities, for both the local and conjugate regions. The E-region dynamo dominates during the day but at night the F-region and convection are more important. This model provides much better agreement with observations of the F-region drifts than previous models. Results indicate that larger magnitudes occur at night, and that daily variation is dominated by the diurnal mode. Seasonal variations in conductivities and thermospheric winds indicate a reversal in direction in the early morning during winter from south to northward. On magnetic perturbed days and the drifts deviate rather strongly from the quiet days average, especially around 13 L.T. for the northward and 18 L.T. for the westward component.

  3. The Jovian ionospheric E region

    NASA Astrophysics Data System (ADS)

    Kim, Y. H.; Fox, J. L.

    1991-02-01

    A model of the Jovian ionosphere was constructed, that includes direct photoionization of hydrocarbon molecules. A high-resolution solar spectrum was synthesized from Hinteregger's solar maximum spectrum (F79050N), and high-resolution cross sections for photoabsorption by H2 bands in the range 842 to 1116 A were constructed. Two strong solar lines and about 30 percent of the continuum flux between 912 and 1116 A penetrate below the methane homopause despite strong absorption by CH4 and H2. It is found that hydrocarbons (mainly C2H2 are ionized at a maximum rate of 55/cu cm per sec at 320 km above the ammonia cloud tops. The hydrocarbon ions produced are quickly converted to more complex hydrocarbon ions through reactions with CH4, C2H2, C2H6, and C2H4. It is found that a hydrocarbon ion layer is formed near 320 km that is about 50 km wide with a peak density in excess of 10,000/cu cm.

  4. Meteoric Ions in Planetary Ionospheres

    NASA Technical Reports Server (NTRS)

    Pesnell, W. D.; Grebowsky, Joseph M.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Solar system debris, in the form of meteoroids, impacts every planet. The flux, relative composition and speed of the debris at each planet depends on the planet's size and location in the solar system. Ablation in the atmosphere evaporates the meteoric material and leaves behind metal atoms. During the ablation process metallic ions are formed by impact ionization. For small inner solar system planets, including Earth, this source of ionization is typically small compared to either photoionization or charge exchange with ambient molecular ions. For Earth, the atmosphere above the main deposition region absorbs the spectral lines capable of ionizing the major metallic atoms (Fe and Mg) so that charge exchange with ambient ions is the dominant source. Within the carbon dioxide atmosphere of Mars (and possibly Venus), photoionization is important in determining the ion density. For a heavy planet like Jupiter, far from the sun, impact ionization of ablated neutral atoms by impacts with molecules becomes a prominent source of ionization due to the gravitational acceleration to high incident speeds. We will describe the processes and location and extent of metal ion layers for Mars, Earth and Jupiter, concentrating on flagging the uncertainties in the models at the present time. This is an important problem, because low altitude ionosphere layers for the planets, particularly at night, probably consist predominantly of metallic ions. Comparisons with Earth will be used to illustrate the differing processes in the three planetary atmospheres.

  5. Experimental evidence of electromagnetic pollution of ionosphere

    NASA Astrophysics Data System (ADS)

    Pronenko, Vira; Korepanov, Valery; Dudkin, Denis

    The Earth’s ionosphere responds to external perturbations originated mainly in the Sun, which is the primary driver of the space weather (SW). But solar activity influences on the ionosphere and the Earth's atmosphere (i.e., the energy transfer in the direction of the Sun-magnetosphere-ionosphere-atmosphere-surface of the Earth), though important, is not a unique factor affecting its state - there is also a significant impact of the powerful natural and anthropogenic processes, which occur on the Earth’s surface and propagating in opposite direction along the Earth’s surface-atmosphere-ionosphere-magnetosphere chain. Numerous experimental data confirm that the powerful sources and consumers of electrical energy (radio transmitters, power plants, power lines and industrial objects) cause different ionospheric phenomena, for example, changes of the electromagnetic (EM) field and plasma in the ionosphere, and affect on the state of the Earth atmosphere. Anthropogenic EM effects in the ionosphere are already observed by the scientific satellites and the consequences of their impact on the ionosphere are not currently known. Therefore, it is very important and urgent task to conduct the statistically significant research of the ionospheric parameters variations due to the influence of the powerful man-made factors, primarily owing to substantial increase of the EM energy production. Naturally, the satellite monitoring of the ionosphere and magnetosphere in the frequency range from tens of hertz to tens of MHz with wide ground support offers the best opportunity to observe the EM energy release, both in the global and local scales. Parasitic EM radiation from the power supply lines, when entering the ionosphere-magnetosphere system, might have an impact on the electron population in the radiation belt. Its interaction with trapped particles will change their energy and pitch angles; as a result particle precipitations might occur. Observations of EM emission by

  6. Ionospheric calibration for single frequency altimeter measurements

    NASA Astrophysics Data System (ADS)

    Schreiner, William S.; Born, George H.; Markin, Robert E.

    1994-03-01

    This study is a preliminary analysis of the effectiveness (in terms of altimeter calibration accuracy) of various ionosphere models and the Global Positioning System (GPS) to calibrate single frequency altimeter height measurements for ionospheric path delay. In particular, the research focused on ingesting GPS Total Electron Content (TEC) data into the physical Parameterized Real-Time Ionospheric Specification Model (PRISM), which estimates the composition of the ionosphere using independent empirical and physical models and has the capability of adjusting to additional ionospheric measurements. Two types of GPS data were used to adjust the PRISM model: GPS receiver station data mapped from line-of-sight observations to the vertical at the point of interest and a grid map (generated at the Jet Propulsion Laboratory) of GPS derived TEC in a sun-fixed longitude frame. The adjusted PRISM TEC values, as well as predictions by the International Reference Ionosphere (IRI-90), a climatological (monthly mean) model of the ionosphere, were compared to TOPEX dual-frequency TEC measurements (considered as truth) for a number of TOPEX sub-satellite tracks. For a 13.6 GHz altimeter, a Total Electron Content (TEC) of 1 TECU 10(exp 16) electrons/sq m corresponds to approximately 0.218 centimeters of range delay. A maximum expected TEC (at solar maximum or during solar storms) of 10(exp 18) electrons/sq m will create 22 centimeters of range delay. Compared with the TOPEX data, the PRISM predictions were generally accurate within the TECU when the sub-satellite track of interest passed within 300 to 400 km of the GPS TEC data or when the track passed through a night-time ionosphere. If neither was the case, in particular if the track passed through a local noon ionosphere, the PRISM values differed by more than 10 TECU and by as much as 40 TECU. The IRI-90 model, with no current ability to unseat GPS data, predicted TEC to a slightly higher error of 12 TECU. The performance of

  7. Ionospheric calibration for single frequency altimeter measurements

    NASA Technical Reports Server (NTRS)

    Schreiner, William S.; Born, George H.; Markin, Robert E.

    1994-01-01

    This study is a preliminary analysis of the effectiveness (in terms of altimeter calibration accuracy) of various ionosphere models and the Global Positioning System (GPS) to calibrate single frequency altimeter height measurements for ionospheric path delay. In particular, the research focused on ingesting GPS Total Electron Content (TEC) data into the physical Parameterized Real-Time Ionospheric Specification Model (PRISM), which estimates the composition of the ionosphere using independent empirical and physical models and has the capability of adjusting to additional ionospheric measurements. Two types of GPS data were used to adjust the PRISM model: GPS receiver station data mapped from line-of-sight observations to the vertical at the point of interest and a grid map (generated at the Jet Propulsion Laboratory) of GPS derived TEC in a sun-fixed longitude frame. The adjusted PRISM TEC values, as well as predictions by the International Reference Ionosphere (IRI-90), a climatological (monthly mean) model of the ionosphere, were compared to TOPEX dual-frequency TEC measurements (considered as truth) for a number of TOPEX sub-satellite tracks. For a 13.6 GHz altimeter, a Total Electron Content (TEC) of 1 TECU 10(exp 16) electrons/sq m corresponds to approximately 0.218 centimeters of range delay. A maximum expected TEC (at solar maximum or during solar storms) of 10(exp 18) electrons/sq m will create 22 centimeters of range delay. Compared with the TOPEX data, the PRISM predictions were generally accurate within the TECU when the sub-satellite track of interest passed within 300 to 400 km of the GPS TEC data or when the track passed through a night-time ionosphere. If neither was the case, in particular if the track passed through a local noon ionosphere, the PRISM values differed by more than 10 TECU and by as much as 40 TECU. The IRI-90 model, with no current ability to unseat GPS data, predicted TEC to a slightly higher error of 12 TECU. The performance of

  8. Polarimetry from the Stratospheric Observatory for Infrared Astronomy (SOFIA)

    NASA Astrophysics Data System (ADS)

    Vaillancourt, J.; Andersson, B.; Young, E.; Ruzek, M. J.

    2012-12-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5-meter infrared airborne telescope in a Boeing 747SP that operates in the stratosphere at altitudes as high as 45,000 feet (14 km). A joint project of NASA and the German Aerospace Center (DLR), SOFIA can conduct photometric, spectroscopic, and imaging observations at wavelengths from 0.3 micron to 1.6 millimeters with an average atmospheric transmission greater than 80 percent across that range. The first-generation instruments span the range from 0.3 to 240 microns. SOFIA's ability to regularly update its instrument complement over its 20-year lifetime will allow for polarimeters with imaging and spectroscopic capabilities; a second-generation imaging polarimeter is currently planned for far-infrared wavelengths. We discuss a sample of possible investigations of interest to the field of planetary science which can be carried out with an airborne polarimeter in SOFIA's near- and mid-infrared wavelength range including studies of comets, asteroids, and proto-stellar disks. A third-generation instrument call, where new polarimetric capabilities may be proposed, is currently planned for Fiscal Year 2014.

  9. Auroral research at the Tromsø Northern Lights Observatory: the Harang directorship, 1928-1946

    NASA Astrophysics Data System (ADS)

    Egeland, Alv; Burke, William J.

    2016-03-01

    The Northern Lights Observatory in Tromsø began as Professor Lars Vegard's dream for a permanent facility in northern Norway, dedicated to the continuous study of auroral phenomenology and dynamics. Fortunately, not only was Vegard an internationally recognized spectroscopist, he was a great salesman and persuaded the Rockefeller Foundation that such an observatory represented an important long-term investment. A shrewd judge of talent, Vegard recognized the scientific and managerial skills of Leiv Harang, a recent graduate from the University of Oslo, and recommended that he become the observatory's first director. In 1929, subsequent to receiving the Rockefeller Foundation grant, the University of Oslo established a low temperature laboratory to support Vegard's spectroscopic investigations. This paper follows the scientific accomplishments of observatory personnel during the 18 years of Harang's directorship. These include: identifying the chemical sources of auroral emissions, discovering the Vegard-Kaplan bands, quantifying height distributions of different auroral forms, interpreting patterns of magnetic field variations, remotely probing auroral electron distribution profiles in the polar ionosphere, and monitoring the evolving states of the ozone layer. The Rockefeller Foundation judges got it right: the Tromsø Nordlysobservatoriet was, and for decades remained, an outstanding scientific investment.

  10. On the VHF radar echoes in the region of midnight aurora: Signs of ground echoes modulated by the ionosphere

    NASA Astrophysics Data System (ADS)

    Kozlovsky, Alexander; Lester, Mark

    2015-03-01

    We present all-sky interferometric meteor radar (MR), VHF (36.9 MHz), observations from Sodankylä Geophysical Observatory and report on the unusual echoes, which were detected at low elevation on the northern horizon, typically during substorms. These echoes have a near-zero Doppler shift, relatively low power, but with a sharp rise to the power peak, short lifetime (less than 2 s), and nonexponential decay (NED). We suggest that such auroral NED echoes are in fact ground backscatter of the MR waves which have been refracted in the ionosphere, passing through the ionosphere in the substorm region, where pulsating aurora (at a frequency higher than 1.7 Hz) occurs and causes quasiperiodic modulation of the wave propagation conditions, which leads to corresponding modulation of the amplitude of return. The MR treats such oscillating signal as meteor trails.

  11. Ionospheric Specifications for SAR Interferometry (ISSI)

    NASA Technical Reports Server (NTRS)

    Pi, Xiaoqing; Chapman, Bruce D; Freeman, Anthony; Szeliga, Walter; Buckley, Sean M.; Rosen, Paul A.; Lavalle, Marco

    2013-01-01

    The ISSI software package is designed to image the ionosphere from space by calibrating and processing polarimetric synthetic aperture radar (PolSAR) data collected from low Earth orbit satellites. Signals transmitted and received by a PolSAR are subject to the Faraday rotation effect as they traverse the magnetized ionosphere. The ISSI algorithms combine the horizontally and vertically polarized (with respect to the radar system) SAR signals to estimate Faraday rotation and ionospheric total electron content (TEC) with spatial resolutions of sub-kilometers to kilometers, and to derive radar system calibration parameters. The ISSI software package has been designed and developed to integrate the algorithms, process PolSAR data, and image as well as visualize the ionospheric measurements. A number of tests have been conducted using ISSI with PolSAR data collected from various latitude regions using the phase array-type L-band synthetic aperture radar (PALSAR) onboard Japan Aerospace Exploration Agency's Advanced Land Observing Satellite mission, and also with Global Positioning System data. These tests have demonstrated and validated SAR-derived ionospheric images and data correction algorithms.

  12. Charge Balance in the Martian Ionosphere

    NASA Astrophysics Data System (ADS)

    Esman, Teresa; Yelle, Roger V.; Stone, Shane W.; Andersson, Laila; Fowler, Christopher Michael; Benna, Mehdi; Eparvier, Francis; Mahaffy, Paul; Ergun, Bob; Elrod, Meredith K.; MAVEN

    2016-10-01

    We present empirical models of the Martian ionosphere in conjunction with data from the Langmuir Probe and Waves (LPW), Neutral Gas and Ion Mass Spectrometer (NGIMS), and Extreme Ultraviolet Monitor (EUVM) instruments aboard the Mars Atmosphere and Volatile Evolution mission (MAVEN) spacecraft. Among the data provided by MAVEN are electron densities and temperatures, ion and neutral densities, and solar extreme ultraviolet (EUV) flux. We explore a number of contributors to the CO2 photoionization rate, with a specific focus on the role of electron temperatures, which, prior to MAVEN, were not well-known. We compare our results with expectations of the ionospheric structure and behavior to confirm our understanding of the basic structure of the Martian ionosphere in the photochemical region. We show that the ionosphere of Mars is well matched by photochemical equilibrium to within the accuracy of the measurements. These results will aid in the development of more complex ionospheric and escape models and lead to a comprehensive and global scale picture of thermal ion escape on Mars.

  13. Infrasonic troposphere-ionosphere coupling in Hawaii

    NASA Astrophysics Data System (ADS)

    Garces, M. A.

    2011-12-01

    The propagation of infrasonic waves in the ionospheric layers has been considered since the 1960's. It is known that space weather can alter infrasonic propagation below the E layer (~120 km altitude), but it was thought that acoustic attenuation was too severe above this layer to sustain long-range propagation. Although volcanoes, earthquakes and tsunamis (all surface sources) appear to routinely excite perturbations in the ionospheric F layer by the propagation of acoustic and acoustic-gravity waves through the atmosphere, there are few reports of the inverse pathway. This paper discusses some of the routine ground-based infrasonic array observations of ionospheric returns from surface sources. These thermospheric returns generally point back towards the source, with an azimuth deviation that can be corrected using the wind velocity profiles in the mesosphere and lower thermosphere. However, the seismic excitation in the North Pacific by the Tohoku earthquake ensonified the coupled lithosphere-atmosphere-ionosphere waveguide in the 0.01 - 0.1 Hz frequency band, producing anomalous signals observed by infrasound arrays in Hawaii. These infrasonic signals propagated at curiously high velocities, suggesting that some assumptions on ionospheric sound generation and propagation could be revisited.

  14. Ionospheric criticial frequencies and solar cycle effects

    NASA Astrophysics Data System (ADS)

    Kilcik, Ali; Ozguc, Atila; Rozelot, Jean Pierre; Yiǧit, Erdal; Elias, Ana; Donmez, Burcin; Yurchyshyn, Vasyl

    2016-07-01

    The long term solar activity dependencies of ionospheric F1 and F2 regions critical frequencies (foF1 and foF2) are investigated observationally for the last four solar cycles (1976-2015). We here show that the ionospheric F1 and F2 regions have different solar activity dependencies in terms of the sunspot group (SG) numbers: F1 region critical frequency (foF1) peaks at the same time with small SG numbers, while the foF2 reaches its maximum at the same time with the large SG numbers especially during the solar cycle 23. Thus, we may conclude that the sensitivities of ionospheric F1 and F2 region critical frequencies to sunspot group (SG) numbers are associated with different physical processes that are yet to be investigated in detail. Such new results provide further evidence that the two ionospheric regions have different responses to the solar activity. We also analyzed short term oscillatory behavior of ionospheric critical frequencies and found some solar signatures.

  15. Impact of X-Class Flares on the Polar Ionosphere

    NASA Astrophysics Data System (ADS)

    Sojka, J. J.; Lewis, M.; David, M.; Schunk, R. W.; Nicolls, M. J.; Woods, T. N.; Eparvier, F.

    2014-12-01

    The ionospheric impact of X-class and large M-class flares has posed severe observational challenges for the ionosonde community. The very strong high frequency (HF) radio absorption associated with the X-class flares creates black-out conditions making ionosonde observations impossible. Similarly incoherent scatter radar (ISR) observations have generated only a few X-class flare impact observations because of limited duty cycle of these radars. With the advent of the NSF Advanced Modular Incoherent Scatter Radar (AMISR) technology it has become possible to operate 24/7 with better than 10 minute cadence. The PFISR, located at Poker Flat, Alaska, has operated in such a mode since March 2007. This has provide a data base that has captured many X-class flares. The irradiance from a subset of these were also observed by the Extreme Ultraviolet Variability Experiment (EVE) on the NASA Solar Dynamics Observatory (SDO) satellite. Hence we are in a position to evaluate modeling approaches that describes E-region ionization via energetic photons as well as the subsequent ionization caused by these photoelectrons. A key issue remains, that associated with the Auger ionization process. This latter topic's relevance will be described from the modeling and future observational needs point of view. The extension of this study into the central polar cap using Resolute Bay, Canada, AMISRs will be discussed.

  16. International Ultraviolet Explorer Observatory operations

    NASA Technical Reports Server (NTRS)

    1985-01-01

    This volume contains the final report for the International Ultraviolet Explorer IUE Observatory Operations contract. The fundamental operational objective of the International Ultraviolet Explorer (IUE) program is to translate competitively selected observing programs into IUE observations, to reduce these observations into meaningful scientific data, and then to present these data to the Guest Observer in a form amenable to the pursuit of scientific research. The IUE Observatory is the key to this objective since it is the central control and support facility for all science operations functions within the IUE Project. In carrying out the operation of this facility, a number of complex functions were provided beginning with telescope scheduling and operation, proceeding to data processing, and ending with data distribution and scientific data analysis. In support of these critical-path functions, a number of other significant activities were also provided, including scientific instrument calibration, systems analysis, and software support. Routine activities have been summarized briefly whenever possible.

  17. International ultraviolet explorer observatory operations

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This volume contains the Final Report for the International Ultraviolet Explorer (IUE) Observatory Operations contract, NAS5-28787. The report summarizes the activities of the IUE Observatory over the 13-month period from November 1985 through November 1986 and is arranged in sections according to the functions specified in the Statement of Work (SOW) of the contract. In order to preserve numerical correspondence between the technical SOW elements specified by the contract and the sections of this report, project management activities (SOW element 0.0.) are reported here in Section 7, following the reports of technical SOW elements 1.0 through 6.0. Routine activities have been summarized briefly whenever possible; statistical compilations, reports, and more lengthy supplementary material are contained in the Appendices.

  18. Boscovich and the Brera Observatory .

    NASA Astrophysics Data System (ADS)

    Antonello, E.

    In the mid 18th century both theoretical and practical astronomy were cultivated in Milan by Barnabites and Jesuits. In 1763 Boscovich was appointed to the chair of mathematics of the University of Pavia in the Duchy of Milan, and the following year he designed an observatory for the Jesuit Collegium of Brera in Milan. The Specola was built in 1765 and it became quickly one of the main european observatories. We discuss the relation between Boscovich and Brera in the framework of a short biography. An account is given of the initial research activity in the Specola, of the departure of Boscovich from Milan in 1773 and his coming back just before his death.

  19. New Geophysical Observatory in Uruguay

    NASA Astrophysics Data System (ADS)

    Sanchez Bettucci, L.; Nuñez, P.; Caraballo, R. R.; Ogando, R.

    2013-05-01

    In 2011 began the installation of the first geophysical observatory in Uruguay, with the aim of developing the Geosciences. The Astronomical and Geophysical Observatory Aiguá (OAGA) is located within the Cerro Catedral Tourist Farm (-34 ° 20 '0 .89 "S/-54 ° 42 '44.72" W, h: 270m). This has the distinction of being located in the center of the South Atlantic Magnetic Anomaly. Geologically is emplaced in a Neoproterozoic basement, in a region with scarce anthropogenic interference. The OAGA has, since 2012, with a GSM-90FD dIdD v7.0 and GSM-90F Overhauser, both of GEM Systems. In addition has a super-SID receiver provided by the Stanford University SOLAR Center, as a complement for educational purposes. Likewise the installation of a seismograph REF TEK-151-120A and VLF antenna is being done since the beginning of 2013.

  20. The NASA airborne astronomy program - A perspective on its contributions to science, technology, and education

    NASA Technical Reports Server (NTRS)

    Larson, Harold P.

    1992-01-01

    The publication records from NASA's airborne observatories are examined to evaluate the contribution of the airborne astronomy program to technological development and scientific/educational progress. The breadth and continuity of program is detailed with reference to its publication history, discipline representation, literature citations, and to the ability of such a program to address nonrecurring and unexpected astronomical phenomena. Community involvement in the airborne-observation program is described in terms of the number of participants, institutional affiliation, and geographic distribution. The program utilizes instruments including heterodyne and grating spectrometers, high-speed photometers, and Fabry-Perot spectrometers with wide total spectral ranges, resolutions, and numbers of channels. The potential of the program for both astronomical training and further scientific, theoretical, and applied development is underscored.

  1. Compton Gamma-Ray Observatory

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This photograph shows the Compton Gamma-Ray Observatory being released from the Remote Manipulator System (RMS) arm aboard the Space Shuttle Atlantis during the STS-35 mission in April 1991. The GRO reentered the Earth's atmosphere and ended its successful mission in June 2000. For nearly 9 years, GRO's Burst and Transient Source Experiment (BATSE), designed and built by the Marshall Space Flight Center, kept an unblinking watch on the universe to alert scientist to the invisible, mysterious gamma-ray bursts that had puzzled them for decades. By studying gamma-rays from objects like black holes, pulsars, quasars, neutron stars, and other exotic objects, scientists could discover clues to the birth, evolution, and death of star, galaxies, and the universe. The gamma-ray instrument was one of four major science instruments aboard the Compton. It consisted of eight detectors, or modules, located at each corner of the rectangular satellite to simultaneously scan the entire universe for bursts of gamma-rays ranging in duration from fractions of a second to minutes. In January 1999, the instrument, via the Internet, cued a computer-controlled telescope at Las Alamos National Laboratory in Los Alamos, New Mexico, within 20 seconds of registering a burst. With this capability, the gamma-ray experiment came to serve as a gamma-ray burst alert for the Hubble Space Telescope, the Chandra X-Ray Observatory, and major gound-based observatories around the world. Thirty-seven universities, observatories, and NASA centers in 19 states, and 11 more institutions in Europe and Russia, participated in BATSE's science program.

  2. Compton Gamma-Ray Observatory

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This photograph shows the Compton Gamma-Ray Observatory (GRO) being deployed by the Remote Manipulator System (RMS) arm aboard the Space Shuttle Atlantis during the STS-37 mission in April 1991. The GRO reentered Earth atmosphere and ended its successful mission in June 2000. For nearly 9 years, the GRO Burst and Transient Source Experiment (BATSE), designed and built by the Marshall Space Flight Center (MSFC), kept an unblinking watch on the universe to alert scientists to the invisible, mysterious gamma-ray bursts that had puzzled them for decades. By studying gamma-rays from objects like black holes, pulsars, quasars, neutron stars, and other exotic objects, scientists could discover clues to the birth, evolution, and death of stars, galaxies, and the universe. The gamma-ray instrument was one of four major science instruments aboard the Compton. It consisted of eight detectors, or modules, located at each corner of the rectangular satellite to simultaneously scan the entire universe for bursts of gamma-rays ranging in duration from fractions of a second to minutes. In January 1999, the instrument, via the Internet, cued a computer-controlled telescope at Las Alamos National Laboratory in Los Alamos, New Mexico, within 20 seconds of registering a burst. With this capability, the gamma-ray experiment came to serve as a gamma-ray burst alert for the Hubble Space Telescope, the Chandra X-Ray Observatory, and major gound-based observatories around the world. Thirty-seven universities, observatories, and NASA centers in 19 states, and 11 more institutions in Europe and Russia, participated in the BATSE science program.

  3. Ny-Alesund Geodetic Observatory

    NASA Technical Reports Server (NTRS)

    Sieber, Moritz

    2013-01-01

    In 2012 the 20-m telescope at Ny-Alesund, Svalbard, operated by the Norwegian Mapping Authority (NMA), took part in 163 out of 168 scheduled sessions of the IVS program. Since spring, all data was transferred by network, and the receiver monitoring computer was replaced by a bus-coupler. In autumn, the NMA received building permission for a new observatory from the Governor of Svalbard. The bidding process and first construction work for the infrastructure will start in 2013.

  4. Ionospheric disturbances during November 30-December 1, 1988. IV - Ionospheric disturbances observed by oblique ionospheric sounding network in Japan

    NASA Astrophysics Data System (ADS)

    Igarashi, Kiyoshi; Takeuchi, Tetsuo

    1992-07-01

    The oblique ionospheric-sounding network of the Communications Research Laboratory (CRL) was used to obtain oblique ionograms every 15 minutes during severe ionospheric disturbances from November 30 through December I, 1988. Vertical-sounding HF signals (l to 25 MHz) from Wakkanai, Akita, Yamagawa, and Okinawa were received at Kokubunji. Oblique ionograms on the night of November 30 exhibit scattered and oblique echoes due to anomalous signal propagation as well as normal echoes. Anomalous propagation occurred when the maximum observable frequency (MOF) largely increased. Furthermore, scattered echoes appeared more frequently and with more intensity on the southernmost path (Okinawa-Kokubunji) than on the northernmost one (Wakkanai-Kokubunji).

  5. Ionosphere-Plasmasphere coupling using the ionosphere-plasmasphere-electrodynamics (IPE) model

    NASA Astrophysics Data System (ADS)

    Maruyama, N.; Richards, P. G.; Fedrizzi, M.; Fuller-Rowell, T. J.; Fang, T. W.; Codrescu, M.; Pierrard, V.; Denton, M.

    2015-12-01

    A close connection between ionospheric SEDs and plasmaspheric plumes has been reported during the main phase of magnetic storms in previous studies. The temporal and spatial variation of the connection has not yet been studied in detail, as the plasmas in ionosphere and plasmasphere get redistributed dynamically during various phases of a storm. Furthermore, how the Ionosphere-Plasmasphere coupling depends on the types of the solar wind driving conditions has not yet been studied. A newly developed global three dimensional ionosphere-plasmasphere-electrodynamics (IPE) model is used to address the coupling between the ionosphere and plasmasphere. IPE model has reproduced the Storm Enhanced Density plume feature in TEC being transported into cusp and over the pole, characterized as the Tongue of Ionization (TOI). Furthermore, the same simulation reveals the plasmaspheric plume like structure in the magnetospheric equatorial plane. Our simulations suggest that neither SAPS nor midlatitude SED bulge is essential in reproducing the SED plume-like features. A term analysis of the ion continuity equations in the IPE model has indicated that the SED plume/TOI feature observed in the ionosphere is produced due primarily to a combination of plasma transport and production/loss, which is supportive of previous studies. However, the plasmaspheric plume responds differently to that of the ionospheric plume depending on the various setting of the numerical experiments. The results indicate a need of a careful examination of the relative importance of the plasma transport between the parallel and perpendicular directions to the magnetic field in both the ionosphere and plasmasphere. In this presentation, we will compare how the ionosphere-plasmasphere coupling depends on the solar wind driving conditions for the selected campaign events.

  6. Imaging the topside ionosphere and plasmasphere with ionospheric tomography using COSMIC GPS TEC

    NASA Astrophysics Data System (ADS)

    Pinto Jayawardena, Talini S.; Chartier, Alex T.; Spencer, Paul; Mitchell, Cathryn N.

    2016-01-01

    GPS-based ionospheric tomography is a well-known technique for imaging the total electron content (TEC) between GPS satellites and receivers. However, as an integral measurement of electron concentration, TEC typically encompasses both the ionosphere and plasmasphere, masking signatures from the topside ionosphere-plasmasphere due to the dominant ionosphere. Imaging these regions requires a technique that isolates TEC in the topside ionosphere-plasmasphere. Multi-Instrument Data Analysis System (MIDAS) employs tomography to image the electron distribution in the ionosphere. Its implementation for regions beyond is yet to be seen due to the different dynamics present above the ionosphere. This paper discusses the extension of MIDAS to image these altitudes using GPS phase-based TEC measurements and follows the work by Spencer and Mitchell (2011). Plasma is constrained to dipole field lines described by Euler potentials, resulting in a distribution symmetrical about the geomagnetic equator. A simulation of an empirical plasmaspheric model by Gallagher et al. (1988) is used to verify the technique by comparing reconstructions of the simulation with the empirical model. The Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) is used as GPS receiver locations. The verification is followed by a validation of the modified MIDAS algorithm, where the regions' TEC is reconstructed from COSMIC GPS phase measurements and qualitatively compared with previous studies using Jason-1 and COSMIC data. Results show that MIDAS can successfully image features/trends of the topside ionosphere-plasmasphere observed in other studies, with deviations in absolute TEC attributed to differences in data set properties and the resolution of the images.

  7. ALOHA Cabled Observatory: Early Results

    NASA Astrophysics Data System (ADS)

    Howe, B. M.; Lukas, R.; Duennebier, F. K.

    2011-12-01

    The ALOHA Cabled Observatory (ACO) was installed 6 June 2011, extending power, network communications and timing to a seafloor node and instruments at 4726 m water depth 100 km north of Oahu. The system was installed using ROV Jason operated from the R/V Kilo Moana. Station ALOHA is the field site of the Hawaii Ocean Time-series (HOT) program that has investigated temporal dynamics in biology, physics, and chemistry since 1988. HOT conducts near monthly ship-based sampling and makes continuous observations from moored instruments to document and study climate and ecosystem variability over semi-diurnal to decadal time scales. The cabled observatory system will provide the infrastructure for continuous, interactive ocean sampling enabling new measurements as well as a new mode of ocean observing that integrates ship and cabled observations. The ACO is a prototypical example of a deep observatory system that uses a retired first-generation fiber-optic telecommunications cable. Sensors provide live video, sound from local and distant sources, and measure currents, pressure, temperature, and salinity. Preliminary results will be presented and discussed.

  8. Vibration budget for observatory equipment

    NASA Astrophysics Data System (ADS)

    MacMartin, Douglas G.; Thompson, Hugh

    2015-07-01

    Vibration from equipment mounted on the telescope and in summit support buildings has been a source of performance degradation at existing astronomical observatories, particularly for adaptive optics performance. Rather than relying only on best practices to minimize vibration, we present here a vibration budget that specifies allowable force levels from each source of vibration in the observatory (e.g., pumps, chillers, cryocoolers, etc.). This design tool helps ensure that the total optical performance degradation due to vibration is less than the corresponding error budget allocation and is also useful in design trade-offs, specifying isolation requirements for equipment, and tightening or widening individual equipment vibration specifications as necessary. The vibration budget relies on model-based analysis of the optical consequences that result from forces applied at different locations and frequencies, including both image jitter and primary mirror segment motion. We develop this tool here for the Thirty Meter Telescope but hope that this approach will be broadly useful to other observatories, not only in the design phase, but for verification and operations as well.

  9. Representation of the Auroral and Polar Ionosphere in the International Reference Ionosphere (IRI)

    NASA Technical Reports Server (NTRS)

    Bilitza, Dieter; Reinisch, Bodo

    2013-01-01

    This issue of Advances in Space Research presents a selection of papers that document the progress in developing and improving the International Reference Ionosphere (IRI), a widely used standard for the parameters that describe the Earths ionosphere. The core set of papers was presented during the 2010 General Assembly of the Committee on Space Research in Bremen, Germany in a session that focused on the representation of the auroral and polar ionosphere in the IRI model. In addition, papers were solicited and submitted from the scientific community in a general call for appropriate papers.

  10. Ionospheric Cubeswarm Concept Study: using low-resource instrumentation for truly multipoint in situ ionospheric observations

    NASA Astrophysics Data System (ADS)

    Hampton, D.; Lynch, K. A.; Earle, G. D.; Mannucci, A. J.; Clayton, R.; Fisher, L. E.; Fernandes, P. A.; Roberts, M.; Zettergren, M. D.

    2015-12-01

    Magnetosphere-ionosphere coupling currents close in the nightside lower ionosphere. These spatially inhomogeneous and time varying volume currents are difficult to capture with in situ observations. Our understanding of M-I coupling systems is limited by our understanding of the actual structure of ionospheric current closure. A path forward includes assimilation of a variety of data sets into increasingly capable ionospheric models. While each data set provides only a piece of the picture, the assimilation process allows optimal use of each piece.An important development for the necessary in situ observations involves making them truly multi-point, and therefore, low-resource. For thermal particle observations, the high densities of the lower ionosphere allow the use of low-gain (current-sensing rather than particle-counting) particle sensors. One observational goal is the definition of the actual structure of ionospheric closure currents. This can be approached with a number of different measurement techniques, in tandem with an ionospheric model, since the closure currents need to follow the rules of electrodynamics and current continuity. Low resource thermal plasma sensors such as retarding potential analyzers and drift meters can provide valuable measurements of plasma parameters, including density and plasma flow, without the need for high voltages or deployable boom systems. These low-resource measurements, which can be reproduced on arrays of in situ observation platforms, used in tandem with proper plasma physics interpretation of their signatures in the disturbed observing environment, and as part of an assimilated data set into an ionospheric model, can allow us to progress in our understanding of ionospheric structuring and its effects on auroral coupling. Now, with increasingly capable multipoint arrays of spacecraft, and quantitative 2D-with-time context from cameras and imagery, we are moving toward truly multipoint studies of the system

  11. An Initial Investigation of Ionospheric Gradients for Detection of Ionospheric Disturbances over Turkey

    NASA Astrophysics Data System (ADS)

    Koroglu, Meltem; Arikan, Feza; Koroglu, Ozan

    2015-04-01

    Ionosphere is an ionized layer of earth's atmosphere which affect the propagation of radio signals due to highly varying electron density structure. Total Electron Content (TEC) and Slant Total Electron Content (STEC) are convenient measures of total electron density along a ray path. STEC model is given by the line integral of the electron density between the receiver and GPS satellite. TEC and STEC can be estimated by observing the difference between the two GPS signal time delays that have different frequencies L1 (1575 MHz) and L2 (1227 MHz). During extreme ionospheric storms ionospheric gradients becomes larger than those of quiet days since time delays of the radio signals becomes anomalous. Ionosphere gradients can be modeled as a linear semi-infinite wave front with constant propagation speed. One way of computing the ionospheric gradients is to compare the STEC values estimated between two neighbouring GPS stations. In this so-called station-pair method, ionospheric gradients are defined by dividing the difference of the time delays of two receivers, that see the same satellite at the same time period. In this study, ionospheric gradients over Turkey are computed using the Turkish National Permanent GPS Network (TNPGN-Active) between May 2009 and September 2012. The GPS receivers are paired in east-west and north-south directions with distances less than 150 km. GPS-STEC for each station are calculated using IONOLAB-TEC and IONOLAB-BIAS softwares (www.ionolab.org). Ionospheric delays are calculated for each paired station for both L1 and L2 frequencies and for each satellite in view with 30 s time resolution. During the investigation period, different types of geomagnetic storms, Travelling Ionospheric Disturbances (TID), Sudden Ionospheric Disturbances (SID) and various earthquakes with magnitudes between 3 to 7.4 have occured. Significant variations in the structure of station-pair gradients have been observed depending on location of station-pairs, the

  12. Ionosphere/microwave beam interaction study

    NASA Technical Reports Server (NTRS)

    Gordon, W. E.; Duncan, L. M.

    1978-01-01

    The microwave beam of the Solar Power Satellite (SPS) is predicted to interact with the ionosphere producing thermal runaway up to an altitude of about 100 kilometers at a power density threshold of 12 mW/cm sq (within a factor of two). The operation of the SPS at two frequencies, 2450 and 5800 MHz, is compared. The ionosphere interaction is less at the higher frequency, but the tropospheric problem scattering from heavy rain and hail is worse at the higher frequency. Microwave signals from communication satellites were observed to scintillate, but there is some concern that the uplink pilot signal may be distorted by the SPS heated ionosphere. The microwave scintillations are only observed in the tropics in the early evenings near the equinoxes. Results indicate that large phase errors in the uplink pilot signal can be reduced.

  13. The ionospheres and plasma tails of comets

    NASA Technical Reports Server (NTRS)

    Mendis, D. A.; Ip, W.-H.

    1977-01-01

    The paper reviews the current state of knowledge about cometary plasma (type I) tails and ionospheres. Observational statistics for type I tails are examined along with spectroscopic observations of plasma tails, identified ion species in such tails, and the morphology of cometary plasma tails and ionospheres. Evidence for a strong interaction between comets and the solar wind is evaluated on the basis of observations of plasma-tail orientations, large accelerations of tail structures, and correlations between disturbances in type I tails and solar-wind or geomagnetic disturbances. The use of comets as solar-wind probes is discussed, the nature of comet-solar-wind interactions is investigated, and ionization sources for cometary gases are considered. Hydrodynamic models of comet-solar-wind interaction are summarized, and the structure and ion chemistry of cometary ionospheres are studied. Observations suggesting that significant magnetic fields are associated with comets are briefly reviewed and interpreted.

  14. Incredibly distant ionospheric responses to earthquake

    NASA Astrophysics Data System (ADS)

    Yusupov, Kamil; Akchurin, Adel

    2015-04-01

    Attempts to observe ionospheric responses to the earthquake has been going on for decades. In recent years, the greatest progress in the study of this question have GPS-measurements with simultaneous HF-measurements. The use of a dense network of GPS-receivers and getting with it sufficiently detailed two-dimensional maps of the total electron content (TEC) greatly clarified the nature of the ionospheric response to strong earthquakes. For ionospheric responses observation, that are remote more than 1000 km from the strong earthquakes epicentres, it is necessary to applying more sensitive methods than GPS. The most experience in the observation of the ionospheric responses to earthquakes accumulated with Doppler sounding. Using these measurements, ionospheric disturbances characteristic features (signature) have been allocated, which associated with the passage of Rayleigh waves on the surface. Particular, this Rayleigh wave signatures allocation is implemented in the Nostradamus coherent backscatter radar. The authors of this method suggest using radar techniques like a sensitive "ionospheric seismometer." The most productive allocation and studying of the vertical structure ionospheric responses could be ionosonde observations. However, their typical 15 minute sounding rate is quite sufficient for observing the regular ionosphere, but it is not enough for studying the ionospheric responses to earthquakes, because ionospheric responses is often seen only in one ionogram and it is absent in adjacent. The decisive factor in establishing the striking ionospheric response to the earthquake was the Tohoku earthquake in 2011, when there was three ionosondes distant at 870-2000 km from the epicentre. These ionosondes simultaneously showed distortion of the F1-layer traces as its multiple stratification (multiple-cusp signature - MCS), which generated by Rayleigh wave. Note that there was another fourth Japanese ionosonde. It is located a little further near boundaries

  15. Ionospheric effects on modern electronic systems

    NASA Astrophysics Data System (ADS)

    Goodman, John M.; Aarons, Jules

    1990-03-01

    A basic overview of ionospheric phenomenology is provided. Some of the modern electronic systems of interest and the extent to which the ionosphere may place limits on design and operation are discussed. The effects of importance to electronic systems are defined, and the effects are discussed by frequency regime: the ELF (less than 3 kHz), VLF (3-30 kHz), and LF (30-300 kHz) bands. Shortwave and earth-space propagation are considered. Special attention is given to systems for which propagation factors are predominantly deleterious; these include satellite communication and navigation systems that operate in the earth-space regime. Special note is made of the fact that the solar maximum is to be reached in 1990-1991 and that maximum ionospheric effects are anticipated during this period, which is predicted to be one of the most active epochs of the last 200 years.

  16. Rocket studies of the lower ionosphere

    NASA Technical Reports Server (NTRS)

    Bowhill, Sidney A.

    1990-01-01

    The earth's ionosphere in the altitude range of 50 to 200 km was investigated by rocket-borne sensors, supplemented by ground-based measurement. The rocket payloads included mass spectrometers, energetic particle detectors, Langmuir probes and radio propagation experiments. Where possible, rocket flights were included in studies of specific phenomena, and the availability of data from other experiments greatly increased the significance of the results. The principal ionospheric phenomena studied were: winter anomaly in radiowave absorption, ozone and molecular oxygen densities, mid-latitude sporadic-E layers, energetic particle precipitation at middle and low latitudes, ionospheric instabilities and turbulence, and solar eclipse effects in the D and E regions. This document lists personnel who worked on the project, and provides a bibliography of resultant publications.

  17. Airborne Particulate Threat Assessment

    SciTech Connect

    Patrick Treado; Oksana Klueva; Jeffrey Beckstead

    2008-12-31

    Aerosol threat detection requires the ability to discern between threat agents and ambient background particulate matter (PM) encountered in the environment. To date, Raman imaging technology has been demonstrated as an effective strategy for the assessment of threat agents in the presence of specific, complex backgrounds. Expanding our understanding of the composition of ambient particulate matter background will improve the overall performance of Raman Chemical Imaging (RCI) detection strategies for the autonomous detection of airborne chemical and biological hazards. Improving RCI detection performance is strategic due to its potential to become a widely exploited detection approach by several U.S. government agencies. To improve the understanding of the ambient PM background with subsequent improvement in Raman threat detection capability, ChemImage undertook the Airborne Particulate Threat Assessment (APTA) Project in 2005-2008 through a collaborative effort with the National Energy Technology Laboratory (NETL), under cooperative agreement number DE-FC26-05NT42594. During Phase 1 of the program, a novel PM classification based on molecular composition was developed based on a comprehensive review of the scientific literature. In addition, testing protocols were developed for ambient PM characterization. A signature database was developed based on a variety of microanalytical techniques, including scanning electron microscopy, FT-IR microspectroscopy, optical microscopy, fluorescence and Raman chemical imaging techniques. An automated particle integrated collector and detector (APICD) prototype was developed for automated collection, deposition and detection of biothreat agents in background PM. During Phase 2 of the program, ChemImage continued to refine the understanding of ambient background composition. Additionally, ChemImage enhanced the APICD to provide improved autonomy, sensitivity and specificity. Deliverables included a Final Report detailing our

  18. Topside ionospheric response to solar EUV variability

    NASA Astrophysics Data System (ADS)

    Anderson, Phillip C.; Hawkins, Jessica M.

    2016-02-01

    We present an analysis of 23 years of thermal plasma measurements in the topside ionosphere from the Defense Meteorological Satellite Program (DMSP) spacecraft. The H+/O+ ratio and density vary dramatically with the solar cycle; cross-correlation coefficients between E10.7 and the daily averaged densities are greater than 0.85. The ionospheric parameters also vary dramatically with season, particularly at latitudes away from the equator where the solar zenith angle varies greatly with season. There are also 27 day solar rotation periodicities in the density, associated with periodicities in the directly measured solar EUV flux. Empirical orthogonal function analysis captures over 95% of the variation in the density in the first two principal components. The first principal component (PC1) is clearly associated with the solar EUV while the second principal component (PC2) is clearly associated with the solar zenith angle variation. The magnitude of the variation of the response of the topside ionosphere to solar EUV variability is shown to be closely related to the ionospheric composition. This is interpreted as the result of the effect of composition on the scale height in the topside ionosphere and the "pivot effect" in which the variation in density near the F2 peak is amplified by a factor of e at an altitude a scale height above the F2 peak. When the topside ionosphere is H+ dominated during solar minimum, DMSP may be much less than a scale height above the F2 peak while during solar maximum, when it is O+ dominated, DMSP may be several scale heights above the F2 peak.

  19. GNSS data filtering optimization for ionospheric observation

    NASA Astrophysics Data System (ADS)

    D'Angelo, G.; Spogli, L.; Cesaroni, C.; Sgrigna, V.; Alfonsi, L.; Aquino, M. H. O.

    2015-12-01

    In the last years, the use of GNSS (Global Navigation Satellite Systems) data has been gradually increasing, for both scientific studies and technological applications. High-rate GNSS data, able to generate and output 50-Hz phase and amplitude samples, are commonly used to study electron density irregularities within the ionosphere. Ionospheric irregularities may cause scintillations, which are rapid and random fluctuations of the phase and the amplitude of the received GNSS signals. For scintillation analysis, usually, GNSS signals observed at an elevation angle lower than an arbitrary threshold (usually 15°, 20° or 30°) are filtered out, to remove the possible error sources due to the local environment where the receiver is deployed. Indeed, the signal scattered by the environment surrounding the receiver could mimic ionospheric scintillation, because buildings, trees, etc. might create diffusion, diffraction and reflection. Although widely adopted, the elevation angle threshold has some downsides, as it may under or overestimate the actual impact of multipath due to local environment. Certainly, an incorrect selection of the field of view spanned by the GNSS antenna may lead to the misidentification of scintillation events at low elevation angles. With the aim to tackle the non-ionospheric effects induced by multipath at ground, in this paper we introduce a filtering technique, termed SOLIDIFY (Standalone OutLiers IDentIfication Filtering analYsis technique), aiming at excluding the multipath sources of non-ionospheric origin to improve the quality of the information obtained by the GNSS signal in a given site. SOLIDIFY is a statistical filtering technique based on the signal quality parameters measured by scintillation receivers. The technique is applied and optimized on the data acquired by a scintillation receiver located at the Istituto Nazionale di Geofisica e Vulcanologia, in Rome. The results of the exercise show that, in the considered case of a noisy

  20. Multi-GNSS for Ionospheric Scintillation Studies

    NASA Astrophysics Data System (ADS)

    Morton, Y.

    2015-12-01

    GNSS have been widely used for ionospheric monitoring. We anticipate over 160 GNSS satellites broadcasting 400 signals by 2023, nearly double the number today. With their well-defined signal structures, high spatial density and spectral diversity, GNSS offers low cost and distributed passive sensing of ionosphere effects. There are, however, many challenges to utilize GNSS resources to characterize and forecast ionospheric scintillation. Originally intended for navigation purposes, GNSS receivers are designed to filter out nuisance effects due to ionosphere effects. GNSS measurements are plagued with errors from multipath, oscillator jitters, processing artifacts, and neutral atmosphere effects. Strong scintillation events are often characterized by turbulent structures in ionosphere, causing simultaneous deep amplitude fading and abrupt carrier phase changes. The combined weak signal and high carrier dynamics imposes conflicting requirements for GNSS receiver design. Therefore, GNSS receivers often experience cycle slips and loss of lock of signals during strong scintillation events. High quality, raw GNSS signals bearing space weather signatures and robust receiver algorithms designed to capture these signatures are needed in order for GNSS to be a reliable and useful agent for scintillation monitoring and forecasting. Our event-driven, reconfigurable data collection system is designed to achieve this purpose. To date, our global network has collected ~150TB of raw GNSS data during space weather events. A suite of novel receiver processing algorithms has been developed by exploitating GNSS spatial, frequency, temporal, and constellation diversity to process signals experiencing challenging scintillation impact. The algorithms and data have advanced our understanding of scintillation impact on GNSS, lead to more robust receiver technologies, and enabled high spatial and temporal resolution depiction of ionosphere responses to solar and geomagnetic conditions. This

  1. Diurnal variations of Titan's ionosphere

    NASA Astrophysics Data System (ADS)

    Cui, J.; Galand, M.; Yelle, R. V.; Vuitton, V.; Wahlund, J.-E.; Lavvas, P. P.; Müller-Wodarg, I. C. F.; Cravens, T. E.; Kasprzak, W. T.; Waite, J. H.

    2009-06-01

    We present our analysis of the diurnal variations of Titan's ionosphere (between 1000 and 1300 km) based on a sample of Ion Neutral Mass Spectrometer (INMS) measurements in the Open Source Ion (OSI) mode obtained from eight close encounters of the Cassini spacecraft with Titan. Although there is an overall ion depletion well beyond the terminator, the ion content on Titan's nightside is still appreciable, with a density plateau of ˜700 cm-3 below ˜1300 km. Such a plateau is a combined result of significant depletion of light ions and modest depletion of heavy ones on Titan's nightside. We propose that the distinctions between the diurnal variations of light and heavy ions are associated with their different chemical loss pathways, with the former primarily through “fast” ion-neutral chemistry and the latter through “slow” electron dissociative recombination. The strong correlation between the observed night-to-day ion density ratios and the associated ion lifetimes suggests a scenario in which the ions created on Titan's dayside may survive well to the nightside. The observed asymmetry between the dawn and dusk ion density profiles also supports such an interpretation. We construct a time-dependent ion chemistry model to investigate the effect of ion survival associated with solid body rotation alone as well as superrotating horizontal winds. For long-lived ions, the predicted diurnal variations have similar general characteristics to those observed. However, for short-lived ions, the model densities on the nightside are significantly lower than the observed values. This implies that electron precipitation from Saturn's magnetosphere may be an additional and important contributor to the densities of the short-lived ions observed on Titan's nightside.

  2. Ionospheric tomography using the FORTE satellite

    SciTech Connect

    Murphy, T.C.

    1993-08-01

    The possibility of obtaining ionospheric profile data via tomographic techniques has elicited considerable interest in recent years. The input data for the method is a set of total electron content measurements along intersecting lines of sight which form a grid. This can conveniently be provided by a fast-moving satellite with a VHF beacon which will generate the multiple paths needed for effective tomography. Los Alamos and Sandia National Laboratories will launch and operate the FORTE satellite for the US Department of Energy, with launch scheduled in 1995. FORTE will provide such a beacon. Additionally, wideband VHF receivers aboard the satellite will allow corraborative measurements of ionospheric profile parameters in some cases.

  3. Using DORIS measurements for ionosphere modeling

    NASA Astrophysics Data System (ADS)

    Dettmering, Denise; Schmidt, Michael; Limberger, Marco

    2013-04-01

    Nowadays, most of the ionosphere models used in geodesy are based on terrestrial GNSS measurements and describe the Vertical Total Electron Content (VTEC) depending on longitude, latitude, and time. Since modeling the height distribution of the electrons is difficult due to the measurement geometry, the VTEC maps are based on the the assumption of a single-layer ionosphere. Moreover, the accuracy of the VTEC maps is different for different regions of the Earth, because the GNSS stations are unevenly distributed over the globe and some regions (especially the ocean areas) are not very well covered by observations. To overcome the unsatisfying measurement geometry of the terrestrial GNSS measurements and to take advantage of the different sensitivities of other space-geodetic observation techniques, we work on the development of multi-dimensional models of the ionosphere from the combination of modern space-geodetic satellite techniques. Our approach consists of a given background model and an unknown correction part expanded in terms of B-spline functions. Different space-geodetic measurements are used to estimate the unknown model coefficients. In order to take into account the different accuracy levels of the observations, a Variance Component Estimation (VCE) is applied. We already have proven the usefulness of radio occultation data from space-borne GPS receivers and of two-frequency altimetry data. Currently, we test the capability of DORIS observations to derive ionospheric parameters such as VTEC. Although DORIS was primarily designed for precise orbit computation of satellites, it can be used as a tool to study the Earth's ionosphere. The DORIS ground beacons are almost globally distributed and the system is on board of various Low Earth Orbiters (LEO) with different orbit heights, such as Jason-2, Cryosat-2, and HY-2. The last generation of DORIS receivers directly provides phase measurements on two frequencies. In this contribution, we test the DORIS

  4. Ionospheric effects of solar x-rays

    NASA Astrophysics Data System (ADS)

    Danskin, Donald

    2016-07-01

    The ionospheric absorption of radio waves caused by solar x-ray bursts is measured directly by Riometers from the Canada Riometer Array. The absorption is found to be proportional to the square root of the flux intensity of the X-ray burst with time delays of 18-20 seconds between the peak X-ray emission and absorption in the ionosphere. A detailed analysis showed that some X-ray flares during 2011-2014 are more effective at producing absorption than others. Solar longitude of X-ray burst for several X-class flares shows no consistent pattern of enhancement in the absorption.

  5. Nonstationary coupling between the magnetosphere and ionosphere

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1983-01-01

    Resonant coupling of large scale MHD waves to small scale kinetic Alfven waves is described. The small-scale waves drive field-aligned currents tens of micro A/sqm into the ionosphere with accelerated electrons of energies a few keV. Bounce resonant interaction with standing kinetic Alfven waves may precipitate higher energy electrons. East-west aligned arcs should be thinnest and move polewards relative to the plasma at the poleward edge. Downward travelling wave packets trap electrons between the wave front and the ionosphere whose energy is below the peak energy and whose phase-space density should be independent of the peak energy.

  6. Airborne GLM Simulator (FEGS)

    NASA Astrophysics Data System (ADS)

    Quick, M.; Blakeslee, R. J.; Christian, H. J., Jr.; Stewart, M. F.; Podgorny, S.; Corredor, D.

    2015-12-01

    Real time lightning observations have proven to be useful for advanced warning and now-casting of severe weather events. In anticipation of the launch of the Geostationary Lightning Mapper (GLM) onboard GOES-R that will provide continuous real time observations of total (both cloud and ground) lightning, the Fly's Eye GLM Simulator (FEGS) is in production. FEGS is an airborne instrument designed to provide cal/val measurements for GLM from high altitude aircraft. It consists of a 5 x 5 array of telescopes each with a narrow passband filter to isolate the 777.4 nm neutral oxygen emission triplet radiated by lightning. The telescopes will measure the optical radiance emitted by lightning that is transmitted through the cloud top with a temporal resolution of 10 μs. When integrated on the NASA ER-2 aircraft, the FEGS array with its 90° field-of-view will observe a cloud top area nearly equal to a single GLM pixel. This design will allow FEGS to determine the temporal and spatial variation of light that contributes to a GLM event detection. In addition to the primary telescope array, the instrument includes 5 supplementary optical channels that observe alternate spectral emission features and will enable the use of FEGS for interesting lightning physics applications. Here we present an up-to-date summary of the project and a description of its scientific applications.

  7. Ionospheric plasma dynamics and instability causedby upward currents above thunderstorms

    NASA Astrophysics Data System (ADS)

    Kuo, C. L.; Lee, L. C.

    2015-12-01

    Thunderstorms are electric generators, which drive currents upwardly into the ionosphere. In thispaper, we examine the effects of thunderstorm upward current on the ionosphere. We use a thunderstormmodel to calculate the three-dimensional current flows in the atmosphere and to simulate the upward currentabove the thunderstormwith the tripole-charge structure. The upward current flows into the ionosphere, whilethe associated electric field causes the plasma E × B motion. The caused plasma motion redistributes theplasma density, leading to ionospheric density variations. In the nighttime ionosphere, the E × B motion mayalso cause the formation of plasma bubbles.

  8. Atmosphere-Ionosphere coupling -manifestations in the low latitude ionosphere

    NASA Astrophysics Data System (ADS)

    Pant, Tarun; Sumod, S. G.; Vineeth, C.; Thampi, Smitha; Jose, Lijo; Kishore Kumar, K.; Sreeja, V.; Manju, G.; Ravindran, Sudha; Sridharan, R.; Niranjan, K.; Dabas, R. S.; Das, Rupesh; Alex, S.; Tiwari, Diwakar

    As is known, the extent of the impact of the geomagnetic storms on the vertical coupling of the MLTI regions, especially over low latitudes, is not very well understood. To investigate this aspect of the MLTI coupling, a multi-instrument campaign was conducted during March-April 2006, a period when a few moderate geomagnetic storms occurred, in India. During the campaign period, a Multiwavelength dayglow Photometer (MWDPM) was operated along with ionosonde, magnetometer and a meteor radar from Trivandrum (8.5oN, 76.5oE, 0.5oN diplat.), the dip equatorial station in India. The MWDPM provided the optically estimated daytime mesopause temperature while the meteor radar measured the wind and temperature in the lower thermosphere-upper mesosphere region. The MWDPM also provided the near simultaneous measurements on the thermospheric dayglow (O1D 630 nm). GPS satellite based measurements of total electron content (TEC) over a number of locations in India provided the latitudinal distribution of ionization. The new and important observations made during this campaign are the following: (a) The optically measured daytime mesopause temperature shows a prominent decrease in the afternoon hours during the initial and main phases of the geomagnetic storms. This observation, perhaps, is new and unique. (b) Quasi 2 and 5 day oscillations appear to be modulating the mesopause temperature indicating the presence of planetary waves therein. The wind and temperature variability in the lower thermosphere, obtained using the collocated radar further corroborate with these optical measurements and establish the origin of these waves to be in the lower atmosphere. (c) The Equatorial Electrojet (EEJ) induced magnetic field on the ground also exhibit similar variability indicating the presence of these planetary scale oscillations, also in the ionospheric dynamo region. (d) The simultaneously measured thermospheric dayglow (O1D 630 nm) also shows an intensification of a quasi 2-and 5-day

  9. The Great Geospace Observatory and Simultaneous Missions of Opportunity

    NASA Technical Reports Server (NTRS)

    Donovan, Eric; Brandt, Pontus; Sibeck, David; Spann, James; Lester, Mark

    2011-01-01

    A predictive understanding of the sun to geospace environment is one of the main goals of ILWS. This can only be achieved through a "system-level" approach, meaning long-term, simultaneous, continuous observations across the relevant scales of the magnetosphere and ionosphere/thermosphere (IT). To date such an approach, which must involve simultaneous, multi-scale, global imaging of different geospace regions, has not been carried out for a complete geomagnetic storm. Such imagery, now routine for the Solar community, is of critical scientific importance and captures public imagination. Its absence in geospace studies has limited the growth and impact of geospace science. In this presentation, we discuss a concept called the Great Geospace Observatory, which would involve coordinated geospace imaging through an international effort of multiple, simultaneous Missions of Opportunity. In this way, the cost would be spread among different agencies as well as putting remote sensors in vantage points optimized for each type of imaging. 24/7 auroral imaging from weather satellites on Molniya (or similar) orbits, EUV imaging of the plasmasphere from high-inclination orbits, continuous and global ENA imaging from geosynchronous commercial satellites, and continuous X-ray imaging of the cusp and magnetosheath from a high-altitude dedicated probe would quantitatively track system-level dynamics at through substorms, sawtooth events, steady magnetospheric convection, and storms; studying energy and mass coupling between the solar wind, magnetosphere, and the upper atmosphere. In our minds, The Great Geospace Observatory represents the next strategic step for ILWS and needs to be seriously considered.

  10. A review of ionospheric effects on Earth-space propagation

    NASA Technical Reports Server (NTRS)

    Klobuchar, J. A.

    1984-01-01

    A short description is given of each ionospheric total electron content (TEC) effect upon radio waves, along with a representative value of the magnitude of each of these effects under normal ionospheric conditions. A discussion is given of the important characteristics of average ionospheric TEC behavior and the temporal and spatial variability of TEC. Radio waves undergo several effects when they pass through the Earth's ionosphere. One of the most important of these effects is a retardation, or group delay, on the modulation or information carried on the radio wave that is due to its encounter with the free, thermal electrons in the Earth's ionosphere. Other effects the ionosphere has on radio waves include: radio frequency (RF) carrier phase advance; Doppler shift of the RF carrier of the radio wave; Faraday rotation of the plane of polarization of linearly polarized waves; angular refraction or bending of the radio wave path as it travels through the ionosphere; and amplitude and phase scintillations.

  11. Ionospheric effects during severe space weather events seen in ionospheric service data products

    NASA Astrophysics Data System (ADS)

    Jakowski, Norbert; Danielides, Michael; Mayer, Christoph; Borries, Claudia

    Space weather effects are closely related to complex perturbation processes in the magnetosphere-ionosphere-thermosphere systems, initiated by enhanced solar energy input. To understand and model complex space weather processes, different views on the same subject are helpful. One of the ionosphere key parameters is the Total Electron Content (TEC) which provides a first or-der approximation of the ionospheric range error in Global Navigation Satellite System (GNSS) applications. Additionally, horizontal gradients and time rate of change of TEC are important for estimating the perturbation degree of the ionosphere. TEC maps can effectively be gener-ated using ground based GNSS measurements from global receiver networks. Whereas ground based GNSS measurements provide good horizontal resolution, space based radio occultation measurements can complete the view by providing information on the vertical plasma density distribution. The combination of ground based TEC and vertical sounding measurements pro-vide essential information on the shape of the vertical electron density profile by computing the equivalent slab thickness at the ionosonde station site. Since radio beacon measurements at 150/400 MHz are well suited to trace the horizontal structure of Travelling Ionospheric Dis-turbances (TIDs), these data products essentially complete GNSS based TEC mapping results. Radio scintillation data products, characterising small scale irregularities in the ionosphere, are useful to estimate the continuity and availability of transionospheric radio signals. The different data products are addressed while discussing severe space weather events in the ionosphere e.g. events in October/November 2003. The complementary view of different near real time service data products is helpful to better understand the complex dynamics of ionospheric perturbation processes and to forecast the development of parameters customers are interested in.

  12. Observatory Sponsoring Astronomical Image Contest

    NASA Astrophysics Data System (ADS)

    2005-05-01

    Forget the headphones you saw in the Warner Brothers thriller Contact, as well as the guttural throbs emanating from loudspeakers at the Very Large Array in that 1997 movie. In real life, radio telescopes aren't used for "listening" to anything - just like visible-light telescopes, they are used primarily to make images of astronomical objects. Now, the National Radio Astronomy Observatory (NRAO) wants to encourage astronomers to use radio-telescope data to make truly compelling images, and is offering cash prizes to winners of a new image contest. Radio Galaxy Fornax A Radio Galaxy Fornax A Radio-optical composite image of giant elliptical galaxy NGC 1316, showing the galaxy (center), a smaller companion galaxy being cannibalized by NGC 1316, and the resulting "lobes" (orange) of radio emission caused by jets of particles spewed from the core of the giant galaxy Click on image for more detail and images CREDIT: Fomalont et al., NRAO/AUI/NSF "Astronomy is a very visual science, and our radio telescopes are capable of producing excellent images. We're sponsoring this contest to encourage astronomers to make the extra effort to turn good images into truly spectacular ones," said NRAO Director Fred K.Y. Lo. The contest, offering a grand prize of $1,000, was announced at the American Astronomical Society's meeting in Minneapolis, Minnesota. The image contest is part of a broader NRAO effort to make radio astronomical data and images easily accessible and widely available to scientists, students, teachers, the general public, news media and science-education professionals. That effort includes an expanded image gallery on the observatory's Web site. "We're not only adding new radio-astronomy images to our online gallery, but we're also improving the organization and accessibility of the images," said Mark Adams, head of education and public outreach (EPO) at NRAO. "Our long-term goal is to make the NRAO Image Gallery an international resource for radio astronomy imagery

  13. The Liverpool Bay Coastal Observatory

    NASA Astrophysics Data System (ADS)

    Howarth, John; Palmer, Matthew

    2011-11-01

    A pilot Coastal Observatory has been established in Liverpool Bay which integrates (near) real-time measurements with coupled models and whose results are displayed on the web. The aim is to understand the functioning of coastal seas, their response to natural forcing and the consequences of human activity. The eastern Irish Sea is an apt test site, since it encompasses a comprehensive range of processes found in tidally dominated coastal seas, including near-shore physical and biogeochemical processes influenced by estuarine inflows, where both vertical and horizontal gradients are important. Applications include hypernutrification, since the region receives significantly elevated levels of nutrient inputs, shoreline management (coastal flooding and beach erosion/accretion), and understanding present conditions to predict the impact of climate change (for instance if the number and severity of storms, or of high or low river flows, change). The integrated measurement suite which started in August 2002 covers a range of space and time scales. It includes in situ time series, four to six weekly regional water column surveys, an instrumented ferry, a shore-based HF radar system measuring surface currents and waves, coastal tide gauges and visible and infra-red satellite data. The time series enable definition of the seasonal cycle, its inter-annual variability and provide a baseline from which the relative importance of events can be quantified. A suite of nested 3D hydrodynamic, wave and ecosystem models is run daily, focusing on the observatory area by covering the ocean/shelf of northwest Europe (at 12-km resolution) and the Irish Sea (at 1.8 km), and Liverpool Bay at the highest resolution of 200 m. The measurements test the models against events as they happen in a truly 3D context. All measurements and model outputs are displayed freely on the Coastal Observatory website (http://cobs.pol.ac.uk) for an audience of researchers, education, coastal managers and the

  14. The Arecibo Observatory Space Academy

    NASA Astrophysics Data System (ADS)

    Rodriguez-Ford, Linda A.; Zambrano-Marin, Luisa; Petty, Bryan M.; Sternke, Elizabeth; Ortiz, Andrew M.; Rivera-Valentin, Edgard G.

    2015-11-01

    The Arecibo Observatory Space Academy (AOSA) is a ten (10) week pre-college research program for students in grades 9-12. Our mission is to prepare students for academic and professional careers by allowing them to receive an independent and collaborative research experience on topics related to space and aide in their individual academic and social development. Our objectives are to (1) Supplement the student’s STEM education via inquiry-based learning and indirect teaching methods, (2) Immerse students in an ESL environment, further developing their verbal and written presentation skills, and (3) To foster in every student an interest in science by exploiting their natural curiosity and knowledge in order to further develop their critical thinking and investigation skills. AOSA provides students with the opportunity to share lectures with Arecibo Observatory staff, who have expertise in various STEM fields. Each Fall and Spring semester, selected high school students, or Cadets, from all over Puerto Rico participate in this Saturday academy where they receive experience designing, proposing, and carrying out research projects related to space exploration, focusing on four fields: Physics/Astronomy, Biology, Engineering, and Sociology. Cadets get the opportunity to explore their topic of choice while practicing many of the foundations of scientific research with the goal of designing a space settlement, which they present at the NSS-NASA Ames Space Settlement Design Contest. At the end of each semester students present their research to their peers, program mentors, and Arecibo Observatory staff. Funding for this program is provided by NASA SSERVI-LPI: Center for Lunar Science and Exploration with partial support from the Angel Ramos Visitor Center through UMET and management by USRA.

  15. The CEOS Recovery Observatory Pilot

    NASA Astrophysics Data System (ADS)

    Hosford, S.; Proy, C.; Giros, A.; Eddy, A.; Petiteville, I.; Ishida, C.; Gaetani, F.; Frye, S.; Zoffoli, S.; Danzeglocke, J.

    2015-04-01

    Over the course of the last decade, large populations living in vulnerable areas have led to record damages and substantial loss of life in mega-disasters ranging from the deadly Indian Ocean tsunami of 2004 and Haiti earthquake of 2010; the catastrophic flood damages of Hurricane Katrina in 2005 and the Tohoku tsunami of 2011, and the astonishing extent of the environmental impact of the Deepwater Horizon explosion in 2009. These major catastrophes have widespread and long-lasting impacts with subsequent recovery and reconstruction costing billions of euros and lasting years. While satellite imagery is used on an ad hoc basis after many disasters to support damage assessment, there is currently no standard practice or system to coordinate acquisition of data and facilitate access for early recovery planning and recovery tracking and monitoring. CEOS led the creation of a Recovery Observatory Oversight Team, which brings together major recovery stakeholders such as the UNDP and the World Bank/Global Facility for Disaster Reduction and Recovery, value-adding providers and leading space agencies. The principal aims of the Observatory are to: 1. Demonstrate the utility of a wide range of earth observation data to facilitate the recovery and reconstruction phase following a major catastrophic event; 2. Provide a concrete case to focus efforts in identifying and resolving technical and organizational obstacles to facilitating the visibility and access to a relevant set of EO data; and 3. Develop dialogue and establish institutional relationships with the Recovery phase user community to best target data and information requirements; The paper presented here will describe the work conducted in preparing for the triggering of a Recovery Observatory including support to rapid assessments and Post Disaster Needs Assessments by the EO community.

  16. Quantifying Urban Groundwater in Environmental Field Observatories

    NASA Astrophysics Data System (ADS)

    Welty, C.; Miller, A. J.; Belt, K.; Smith, J. A.; Band, L. E.; Groffman, P.; Scanlon, T.; Warner, J.; Ryan, R. J.; Yeskis, D.; McGuire, M. P.

    2006-12-01

    Despite the growing footprint of urban landscapes and their impacts on hydrologic and biogeochemical cycles, comprehensive field studies of urban water budgets are few. The cumulative effects of urban infrastructure (buildings, roads, culverts, storm drains, detention ponds, leaking water supply and wastewater pipe networks) on temporal and spatial patterns of groundwater stores, fluxes, and flowpaths are poorly understood. The goal of this project is to develop expertise and analytical tools for urban groundwater systems that will inform future environmental observatory planning and that can be shared with research teams working in urban environments elsewhere. The work plan for this project draws on a robust set of information resources in Maryland provided by ongoing monitoring efforts of the Baltimore Ecosystem Study (BES), USGS, and the U.S. Forest Service working together with university scientists and engineers from multiple institutions. A key concern is to bridge the gap between small-scale intensive field studies and larger-scale and longer-term hydrologic patterns using synoptic field surveys, remote sensing, numerical modeling, data mining and visualization tools. Using the urban water budget as a unifying theme, we are working toward estimating the various elements of the budget in order to quantify the influence of urban infrastructure on groundwater. Efforts include: (1) comparison of base flow behavior from stream gauges in a nested set of watersheds at four different spatial scales from 0.8 to 171 km2, with diverse patterns of impervious cover and urban infrastructure; (2) synoptic survey of well water levels to characterize the regional water table; (3) use of airborne thermal infrared imagery to identify locations of groundwater seepage into streams across a range of urban development patterns; (4) use of seepage transects and tracer tests to quantify the spatial pattern of groundwater fluxes to the drainage network in selected subwatersheds; (5

  17. The Orbiting Carbon Observatory (OCO)

    NASA Technical Reports Server (NTRS)

    Miller, Charles E.

    2005-01-01

    CO2 is the principal human generated driver of climate change. Accurate forecasting of future climate requires an improved understanding of the global carbon cycle and its interaction with the climate system. The Orbiting Carbon Observatory (OCO) will make global, space-based observations of atmospheric CO2 with the precision, resolution, and coverage needed to understand sources and sinks. OCO data will provide critical information for decision makers including the scientific basis for policy formulation, guide for carbon management strategies and treaty monitoring.

  18. the Large Aperture GRB Observatory

    SciTech Connect

    Bertou, Xavier

    2009-04-30

    The Large Aperture GRB Observatory (LAGO) aims at the detection of high energy photons from Gamma Ray Bursts (GRB) using the single particle technique (SPT) in ground based water Cherenkov detectors (WCD). To reach a reasonable sensitivity, high altitude mountain sites have been selected in Mexico (Sierra Negra, 4550 m a.s.l.), Bolivia (Chacaltaya, 5300 m a.s.l.) and Venezuela (Merida, 4765 m a.s.l.). We report on the project progresses and the first operation at high altitude, search for bursts in 6 months of preliminary data, as well as search for signal at ground level when satellites report a burst.

  19. Airborne Laser Polar Nephelometer

    NASA Technical Reports Server (NTRS)

    Grams, Gerald W.

    1973-01-01

    A polar nephelometer has been developed at NCAR to measure the angular variation of the intensity of light scattered by air molecules and particles. The system has been designed for airborne measurements using outside air ducted through a 5-cm diameter airflow tube; the sample volume is that which is common to the intersection of a collimated source beam and the detector field of view within the airflow tube. The source is a linearly polarized helium-neon laser beam. The optical system defines a collimated field-of-view (0.5deg half-angle) through a series of diaphragms located behind a I72-mm focal length objective lens. A photomultiplier tube is located immediately behind an aperture in the focal plane of the objective lens. The laser beam is mechanically chopped (on-off) at a rate of 5 Hz; a two-channel pulse counter, synchronized to the laser output, measures the photomultiplier pulse rate with the light beam both on and off. The difference in these measured pulse rates is directly proportional to the intensity of the scattered light from the volume common to the intersection of the laser beam and the detector field-of-view. Measurements can be made at scattering angles from 15deg to 165deg with reference to the direction of propagation of the light beam. Intermediate angles are obtained by selecting the angular increments desired between these extreme angles (any multiple of 0.1deg can be selected for the angular increment; 5deg is used in normal operation). Pulses provided by digital circuits control a stepping motor which sequentially rotates the detector by pre-selected angular increments. The synchronous photon-counting system automatically begins measurement of the scattered-light intensity immediately after the rotation to a new angle has been completed. The instrument has been flown on the NASA Convair 990 airborne laboratory to obtain data on the complex index of refraction of atmospheric aerosols. A particle impaction device is operated simultaneously

  20. Ionospheric precursors for crustal earthquakes in Italy

    NASA Astrophysics Data System (ADS)

    Perrone, L.; Korsunova, L. P.; Mikhailov, A. V.

    2010-04-01

    Crustal earthquakes with magnitude 6.0>M≥5.5 observed in Italy for the period 1979-2009 including the last one at L'Aquila on 6 April 2009 were considered to check if the earlier obtained relationships for ionospheric precursors for strong Japanese earthquakes are valid for the Italian moderate earthquakes. The ionospheric precursors are based on the observed variations of the sporadic E-layer parameters (h'Es, fbEs) and foF2 at the ionospheric station Rome. Empirical dependencies for the seismo-ionospheric disturbances relating the earthquake magnitude and the epicenter distance are obtained and they have been shown to be similar to those obtained earlier for Japanese earthquakes. The dependences indicate the process of spreading the disturbance from the epicenter towards periphery during the earthquake preparation process. Large lead times for the precursor occurrence (up to 34 days for M=5.8-5.9) tells about a prolong preparation period. A possibility of using the obtained relationships for the earthquakes prediction is discussed.

  1. The ionosphere and upper atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Kumar, S.

    1975-01-01

    A summary is presented of current understanding of the upper atmosphere and ionosphere of Venus and its interaction with the solar wind, based on data from the Mariner 5 and Mariner 10 fly-bys and on far UV spectra obtained in rocket experiments. The major constituent of the upper atmosphere is CO2. Minor constituents include H, He, O, C, and CO and probably N2, Cl, and S. Although the thermal escape rate is only about 10,000/sq cm/sec, the H content in the exosphere appears to be highly variable. A prominent peak in the ionosphere profile near 140 km, appearing both on the day and nightside, is identified as an F(1) layer. An E layer and possibly an F(2) layer are present at 125 and 170 km, respectively. The dayside ionosphere may be explained in terms of the absorption of solar radiation by CO2, O, and He. The transport of ions from day to nightside may be important in the formation of the nightside ionosphere; an additional source may be needed to explain the nightside E layer. There is observational evidence that the solar wind interacts directly with the Venusian atmosphere, resulting in the formation of a bow shock. This may in part be explained by a balance at the ionopause between the solar wind ram pressure and the planetary plasma pressure.

  2. Phase perturbation measurements through a heated ionosphere

    NASA Technical Reports Server (NTRS)

    Frey, A.; Gordon, W. E.

    1982-01-01

    High frequency radiowaves incident on an overdense (i.e., HF-frequency penetration frequency) ionosphere produce electron density irregularities. The effect of such ionospheric irregularities on the phase of UHF-radiowaves was determined. For that purpose the phase of radiowaves originating from celestial radio sources was observed with two antennas. The radiosources were chosen such that the line of sight to at least one of the antennas (usually both) passed through the modified volume of the ionosphere. Observations at 430 MHz and at 2380 MHz indicate that natural irregularities have a much stronger effect on the UHF phase fluctuations than the HF-induced irregularities for presently achieved HF-power densities of 20-80 uW/sq m. It is not clear whether some of the effects observed are the result of HF-modification of the ionosphere. Upper limits on the phase perturbations produced by HF-modification are 10 deg at 2380 MHz and 80 deg at 430 MHz.

  3. Ionosphere-thermosphere space weather issues.

    NASA Astrophysics Data System (ADS)

    Schunk, R. W.; Sojka, J. J.

    1996-10-01

    Weather disturbances in the ionosphere-thermosphere system can have a detrimental effect on both ground-based and space-based systems. Because of this impact and because this field has matured, it is now appropriate to develop specification and forecast models, with the aim of eventually predicting the occurrence, duration, and intensity of weather effects. As part of the new National Space Weather Program, the CEDAR community will focus on science issues concerning space weather, and this tutorial/review is an expanded version of a tutorial presentation given at the recent CEDAR annual meeting. The tutorial/review provides a brief discussion of weather disturbances and features, the causes of weather, and the status of weather modeling. The features and disturbances discussed include plasma patches, boundary and auroral blobs, Sun-aligned polar cap arcs, the effects of traveling convection vortices and SAID events, the lifetime of density structures, sporadic-E and intermediate layers, spread F and equatorial plasma bubbles, geomagnetic storms and substorms, traveling ionospheric disturbances (TIDs), and the effects of tides and gravity waves propagating from the lower atmosphere. The tutorial/review is only intended to provide an overview of some of the important scientific issues concerning ionospheric-thermospheric weather, with the emphasis on the ionosphere. Tutorials on thermospheric and magnetospheric weather issues are given in companion papers.

  4. Catalog of ionospheric and atmospheric data

    NASA Technical Reports Server (NTRS)

    Liles, J. N.

    1975-01-01

    Available data from planetary atmospheres and ionospheric physics (aeronomy) are announced. Most of the data sets identified result from individual experiments carried on board various spacecraft. A spacecraft Automated Internal Management File and a Nonsatellite Data File are utilized to maintain information on these data. Photoreduced reports produced by these information files are presented. A variety of user oriented indexes are included.

  5. Representing Ionospheric Variability Near the Magnetic Equator

    NASA Astrophysics Data System (ADS)

    Bilitza, D.; Obrou, O.; Adeniyi, J.

    We examine different parameters for the description of ionospheric variability in the equatorial ionosphere. Our data base for this study are foF2 data from the ionosonde stations in Korhogo, Ivory Coast (Lat.= 9.3N, Long. = 5.4W, Dip = 0.7S) and Ouagadougou, Burkina Faso (Lat.= 12N, Long. = 1.8W, Dip = 5.9N). Three years of hourly observations are examined from each station covering low, moderate, and high levels of solar activity. This work is in support of efforts within the International Reference Ionosphere (IRI) project to include a description of ionospheric variability in the IRI model. The goal is to provide the model user with one or two parameters that fully describe the distribution of data around a monthly mean or median for a specific hour, season, and solar activity. The parameters investigated in this study include the mean, the standard deviation, the median, the quartiles, the deciles, the inter-quartile range, the inter-decile range, and several other parameters that help to characterize a non-normal distribution. We will recommend a set of parameters for use in IRI and will discuss the diurnal, seasonal, and solar cycle variations of these parameters near the magnetic equator.

  6. Magnetospheric and Thermospheric Influence on Ionospheric Outflow

    NASA Astrophysics Data System (ADS)

    Garcia-Sage, K.; Moore, T. E.; Mitchell, E. J.; Olson, D. K.

    2013-12-01

    The Fast Auroral SnapshoT (FAST) small explorer has been used extensively to study ionospheric outflow. Past research has used particle and field data to examine the contemporaneous transfer of electromagnetic energy and particle flow downward from the magnetosphere and upward from the ionosphere. Single event studies published by Strangeway et al. [2005] and Brambles et al. [2011, Supporting Online Material] showed that downward electromagnetic energy and particle flow into the ionosphere are correlated with the upward flow of ions out of the ionosphere. It is expected, however, that this correlation will be affected by circumstances that are unique to each specific event, including but not limited to the outflow location (cusp or nightside), preconditioning due to prior geomagnetic activity, and thermospheric neutral densities. Although knowledge of the thermospheric neutral density is usually unavailable, data from the CHAllenging Minisatellite Payload (CHAMP) is able to provide insight into thermospheric populations at altitudes of about 400 km for a few select events. We expand on the previously-mentioned studies by looking at FAST particle and field data for additional events, and we further examine the influence of thermospheric neutral populations, based on CHAMP data.

  7. Method for Canceling Ionospheric Doppler Effect

    NASA Technical Reports Server (NTRS)

    Vessot, R. F. C.

    1982-01-01

    Unified transponder system with hydrogen-maser oscillators at both stations can compensate for both motional and ionospheric components of Doppler shift. Appropriate choices of frequency shift in output of mixer m3. System exploits proportionality between dispersive component of frequency shift and reciprocal of frequency to achieve cancellation of dispersive component at output.

  8. Importance of Ionospheric Gradients for error Correction

    NASA Astrophysics Data System (ADS)

    Ravula, Ramprasad

    Importance of Ionospheric Gradients for error Correction R. Ram Prasad1, P.Nagasekhar2 1Sai Spurthi Institute of Technology-JNTU Hyderabad,2Sai Spurthi Institute of Technology-JNTU Hyderabad Email ID:rams.ravula@gmail.com In India, Indian Space Research Organization (ISRO) has established with an objective to develop space technology and its application to various national tasks. To cater to the needs of civil aviation applications, GPS Aided Geo Augmented Navigation (GAGAN) system is being jointly implemented along with Airports Authority of India (AAI) over the Indian region. The most predominant parameter affecting the navigation accuracy of GAGAN is ionospheric delay which is a function of total number of electrons present in one square meter cylindrical cross sectional area in the line of site direction between the satellite and the user on the earth i.e. Total Electron Content (TEC).The irregular distribution of electron densities i.e. rate of TEC variation, causes Ionospheric gradients such as spatial gradients (Expressed in TECu/km) and temporal gradients (Expressed in TECu /minute). Among the satellite signals arriving to the earth in multiple directions, the signals which suffer from severe ionospheric gradients can be estimated i.e. Rate of TEC Index (ROTI) and Rate of TEC (ROT). These aspects which contribute to errors can be treated for improving GAGAN positional accuracy.

  9. Global Response to Local Ionospheric Mass Ejection

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Fok, M.-C.; Delcourt, D. C.; Slinker, S. P.; Fedder, J. A.

    2010-01-01

    We revisit a reported "Ionospheric Mass Ejection" using prior event observations to guide a global simulation of local ionospheric outflows, global magnetospheric circulation, and plasma sheet pressurization, and comparing our results with the observed global response. Our simulation framework is based on test particle motions in the Lyon-Fedder-Mobarry (LFM) global circulation model electromagnetic fields. The inner magnetosphere is simulated with the Comprehensive Ring Current Model (CRCM) of Fok and Wolf, driven by the transpolar potential developed by the LFM magnetosphere, and includes an embedded plasmaspheric simulation. Global circulation is stimulated using the observed solar wind conditions for the period 24-25 Sept 1998. This period begins with the arrival of a Coronal Mass Ejection, initially with northward, but later with southward interplanetary magnetic field. Test particles are launched from the ionosphere with fluxes specified by local empirical relationships of outflow to electrodynamic and particle precipitation imposed by the MIlD simulation. Particles are tracked until they are lost from the system downstream or into the atmosphere, using the full equations of motion. Results are compared with the observed ring current and a simulation of polar and auroral wind outflows driven globally by solar wind dynamic pressure. We find good quantitative agreement with the observed ring current, and reasonable qualitative agreement with earlier simulation results, suggesting that the solar wind driven global simulation generates realistic energy dissipation in the ionosphere and that the Strangeway relations provide a realistic local outflow description.

  10. Probing geomagnetic storm-driven magnetosphere-ionosphere dynamics in D-region ionosphere using VLF signal propagation characteristics

    NASA Astrophysics Data System (ADS)

    Nwankwo, Victor U. J.; Chakrabarti, Sandip Kumar; Ogunmodimu, Olugbenga

    2016-07-01

    When propagating in the Earth-ionosphere waveguide, the amplitude and phase of VLF/LF radio signals are sensitive to changes in the electrical conductivity of the lower ionosphere. This characteristic makes it useful in studying sudden ionospheric disturbances, especially those related to prompt X-ray flux output from solar flares and gamma ray bursts (GRBs). However, strong geomagnetic disturbances and/or storm conditions are known to produce large and global ionospheric disturbances, which can significantly affect VLF radio propagation in the D region ionosphere. Diurnal VLF signature may also convey other important information, especially those related to geomagnetic disturbance/storm induced ionospheric changes. In this paper, using the data of three propagation paths (at latitudes 40-54º), we analyze in detail the trend of anomalies of VLF diurnal signal under varying solar and geomagnetic space environmental conditions to identify possible geomagnetic footprints on the D region ionosphere.

  11. IRI, an International Standard for the Ionosphere

    NASA Astrophysics Data System (ADS)

    Bilitza, D.; Reinisch, B.; Triskova, L.; Friedrich, M.

    2003-04-01

    The International Reference Ionosphere (IRI) is a data-based model of the ionosphere that has been steadily improved and updated by a joint working group of the Committee on Space Research and the International Union of Radio Science. We will report about the most recent IRI workshops and the improvements and additions planned for the next version of the model. In particular new models will be included for the D-region electron density (Friedrich et al., 2002), and for the ion densities (Triskova et al., 2003) the latter based on Atmosphere Explorer C, D, E and Intercosmos 24 data. A correction term will be introduced in the topside electron density model to alleviate problems at high solar activities and high altitudes (Bilitza, 2002). A special IRI task groups is working on an occurrence probability model for spread-F (Abdu et al., 2003) for inclusion in IRI. A quantitative description of ionospheric variability (standard deviation from monthly mean) is the goal of a special IRI task force activity at the International Center for Theoretical Physics (Radicella 2002). We will also report about activities to update IRI with actual measurements and thus obtain a more accurate description of the actual ionosphere. A proposal to make the IRI model the ISO standard for the ionosphere is now pending before the International Standardization Organization (ISO). The IRI homepage is at http://nssdc.gsfc.nasa.gov/space/model/ionos/iri.html and a web-interface for computing and plotting IRI parameters can be found at http://nssdc.gsfc.nasa.gov/space/model/models/iri.html . Abdu, M. A., J. R de Souza, I. S. Batista, and J. H. A. Sobral, Equatorial Spread F statistics and their empirical modeling for the IRI: A regional model for the Brazilian longitude sector, Adv. Space Res., in press, 2003. Triskova, L., V. Truhlik and J. Smilauer, An empirical model of ion composition in the outer ionosphere, Adv. Space Res., in press, 2003 Bilitza, D., A Correction for the IRI Topside

  12. Antenna Deployment for a Pathfinder Lunar Radio Observatory

    NASA Technical Reports Server (NTRS)

    MacDowall, Robert J.; Minetto, F. A.; Lazio, T. W.; Jones, D. L.; Kasper, J. C.; Burns, J. O.; Stewart, K. P.; Weiler, K. W.

    2012-01-01

    A first step in the development of a large radio observatory on the moon for cosmological or other astrophysical and planetary goals is to deploy a few antennas as a pathfinder mission. In this presentation, we describe a mechanism being developed to deploy such antennas from a small craft, such as a Google Lunar X-prize lander. The antenna concept is to deposit antennas and leads on a polyimide film, such as Kapton, and to unroll the film on the lunar surface. The deployment technique utilized is to launch an anchor which pulls a double line from a reel at the spacecraft. Subsequently, the anchor is set by catching on the surface or collecting sufficient regolith. A motor then pulls in one end of the line, pulling the film off of its roller onto the lunar surface. Detection of a low frequency cutoff of the galactic radio background or of solar radio bursts by such a system would determine the maximum lunar ionospheric density at the time of measurement. The current design and testing, including videos of the deployment, will be presented. These activities are funded in part by the NASA Lunar Science Institute as an activity of the Lunar University Network for Astrophysical Research (LUNAR) consortium. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  13. Antenna Deployment for a Pathfinder Lunar Radio Observatory

    NASA Astrophysics Data System (ADS)

    MacDowall, Robert J.; Minetto, F. A.; Lazio, T. W.; Jones, D. L.; Kasper, J. C.; Burns, J. O.; Stewart, K. P.; Weiler, K. W.

    2012-05-01

    A first step in the development of a large radio observatory on the moon for cosmological or other astrophysical and planetary goals is to deploy a few antennas as a pathfinder mission. In this presentation, we describe a mechanism being developed to deploy such antennas from a small craft, such as a Google Lunar X-prize lander. The antenna concept is to deposit antennas and leads on a polyimide film, such as Kapton, and to unroll the film on the lunar surface. The deployment technique utilized is to launch an anchor which pulls a double line from a reel at the spacecraft. Subsequently, the anchor is set by catching on the surface or collecting sufficient regolith. A motor then pulls in one end of the line, pulling the film off of its roller onto the lunar surface. Detection of a low frequency cutoff of the galactic radio background or of solar radio bursts by such a system would determine the maximum lunar ionospheric density at the time of measurement. The current design and testing, including videos of the deployment, will be presented. These activities are funded in part by the NASA Lunar Science Institute as an activity of the Lunar University Network for Astrophysical Research (LUNAR) consortium. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  14. Protection of the Guillermo Haro Astrophysical Observatory

    NASA Astrophysics Data System (ADS)

    Carrasco, E.; Carraminana, A. P.

    The Guillermo Haro Astrophysical Observatory, with a 2m telescope, is one of only two professional observatories in Mexico. The observatory, run by the InstitutoNacional de Astrofisica, Optica y Electronica (INAOE), is located in the north of Mexico, in Cananea, Sonora. Since 1995 the observatory has faced the potential threat of pollution by an open cast mine to be opened at 3kms from the observatory. In the absence of national or regional laws enforcing protection to astronomical sites in Mexico, considerable effort has been needed to guarantee the conditions of the site. We present the studies carried out to ensure the protection of the Guillermo Haro Observatory from pollution due to dust, light and vibrations.

  15. Data Management Challenges for Airborne NASA Earth Venture Sub-Orbital (EVS-1) Investigations

    NASA Astrophysics Data System (ADS)

    Boyer, A.; Cook, R. B.; Santhana Vannan, S. K.

    2014-12-01

    The ORNL DAAC is developing a technology infrastructure to archive airborne remote sensing observations from two Earth System Science Pathfinder Missions. The two missions are CARVE: Carbon in Arctic Reservoirs Vulnerability Experiment and AirMOSS: Airborne Microwave Observatory of Subcanopy and Subsurface. The two missions are collecting over 140 TB of data from extensive ground-based and airborne instruments. The metadata and documentation requirements necessary for proper archive and dissemination of such transect-based, and often 3-dimensional, airborne data are quite different from the traditional field campaign and satellite remote sensing data streams. Staff at the ORNL DAAC are currently working with the CARVE and AirMOSS teams as well as investigating cyberinfrastructures from other DAACs to develop a metadata and data infrastructure for airborne data that will enable spatial, flight-line, or keyword-based search and discovery, integration as needed of related satellite- and ground-based data sets, and subsetting and visualization tools for both CARVE and AirMOSS. We discuss challenges, progress, and lessons learned.

  16. GPS, GNSS, and Ionospheric Density Gradients

    NASA Astrophysics Data System (ADS)

    Kintner, P. M.; O'Hanlon, B.; Humphreys, T. E.

    2009-12-01

    Ionospheric density and density gradients affect GNSS signals in two ways. They can introduce ranging errors or irregularities that form on the density gradients producing scintillation. Here we focus on the issue of ranging errors. There are two approaches to mitigating ranging errors produced by ionospheric density gradients which can be 20-30 m during major magnetic storms. The first approach is to use a reference receiver(s) to determine the ionospheric contribution to ranging errors. The ranging error is then transmitted to the user for correction within the mobile receiver. This approach is frequently referred to as differential GPS and, when multiple reference receivers are used, the system is referred to as an augmentation system. This approach is vulnerable to ionospheric gradients depending on the reference receiver spacing(s) and latency in applying the correction within the mobile receiver. The second approach is to transmit navigation signals at two frequencies and then use the relative delay between the two signals to both estimate the ranging error and calculate the correct range. Currently the dual frequency technique is used by US military receivers with an encryption key and some civilian receivers which must be stationary and average over times long compared to those required for navigation. However, the technology of space based radio navigation is changing. GPS will soon be a system with three frequencies and multiple codes. Furthermore Europe, Russia, and China are developing independent systems to complement and compete with GPS while India and Japan are developing local systems to enhance GPS performance in their regions. In this talk we address two questions. How do density gradients affect augmentation systems including the social consequences and will the new GPS/GNSS systems with multiple civilian frequencies be able to remove ionospheric errors. The answers are not at all clear.

  17. GNSS station characterisation for ionospheric scintillation applications

    NASA Astrophysics Data System (ADS)

    Romano, Vincenzo; Spogli, Luca; Aquino, Marcio; Dodson, Alan; Hancock, Craig; Forte, Biagio

    2013-10-01

    Ionospheric scintillations are fluctuations in the phase and amplitude of the signals from GNSS (Global Navigation Satellite Systems) occurring when they cross regions of electron density irregularities in the ionosphere. Such disturbances can cause serious degradation of several aspects of GNSS system performance, including integrity, accuracy and availability. The two indices adopted worldwide to characterise ionospheric scintillations are: the amplitude scintillation index, S4, which is the standard deviation of the received power normalised by its mean value, and the phase scintillation index, σΦ, which is the standard deviation of the de-trended carrier phase. Collaborative work between NGI and INGV supports a permanent network of GISTM (GPS Ionospheric Scintillation and TEC Monitor) receivers that covers a wide range of latitudes in the northern European sector. Data from this network has contributed significantly to several papers during the past few years (see e.g. De Franceschi et al., 2008; Aquino et al., 2009; Spogli et al., 2009, 2010; Alfonsi et al., 2011). In these investigations multipath effects and noise that contaminate the scintillation measurements are largely filtered by applying an elevation angle threshold. A deeper analysis of the data quality and the development of a more complex filtering technique can improve the results obtained so far. The structures in the environment of each receiver in the network which contaminate scintillation measurements should be identified in order to improve the quality of the scintillation and TEC data by removing error sources due to the local environment. The analysis in this paper considers a data set characterised by quiet ionospheric conditions of the mid-latitude station located in Nottingham (UK), followed by a case study of the severe geomagnetic storm, which occurred in late 2003, known generally as the "Halloween Storm".

  18. The Compton Gamma Ray Observatory

    NASA Astrophysics Data System (ADS)

    Gehrels, N.; Chipman, E.; Kniffen, D.

    1994-06-01

    The Arthur Holly Compton Gamma Ray Observatory Compton) is the second in NASA's series of great Observatories. Launched on 1991 April 5, Compton represents a dramatic increase in capability over previous gamma-ray missions. The spacecraft and scientific instruments are all in good health, and many significant discoveries have already been made. We describe the capabilities of the four scientific instruments, and the observing program of the first 2 years of the mission. Examples of early discoveries by Compton are enumerated, including the discovery that gamma-ray bursts are isotropic but spatially inhomogeneous in their distribution; the discovery of a new class of high-energy extragalacatic gamma-ray sources, the gamma-ray AGNs; the discovery of emission from SN 1987A in the nuclear line of Co-57; and the mapping of emission from Al-26 in the interstellar medium (ISM) near the Galactic center. Future observations will include deep surveys of selected regions of the sky, long-tem studies of individual objects, correlative studies of objects at gamma-ray and other energies, a Galactic plane survey at intermediate gamma-ray energies, and improved statistics on gamma-ray bursts to search for small anisotropies. After completion of the all-sky survey, a Guest Investigator program is in progress with guest observers' time share increasing from 30% upward for the late mission phases.

  19. A National Solar Digital Observatory

    NASA Astrophysics Data System (ADS)

    Hill, F.

    2000-05-01

    The continuing development of the Internet as a research tool, combined with an improving funding climate, has sparked new interest in the development of Internet-linked astronomical data bases and analysis tools. Here I outline a concept for a National Solar Digital Observatory (NSDO), a set of data archives and analysis tools distributed in physical location at sites which already host such systems. A central web site would be implemented from which a user could search all of the component archives, select and download data, and perform analyses. Example components include NSO's Digital Library containing its synoptic and GONG data, and the forthcoming SOLIS archive. Several other archives, in various stages of development, also exist. Potential analysis tools include content-based searches, visualized programming tools, and graphics routines. The existence of an NSDO would greatly facilitate solar physics research, as a user would no longer need to have detailed knowledge of all solar archive sites. It would also improve public outreach efforts. The National Solar Observatory is operated by AURA, Inc. under a cooperative agreement with the National Science Foundation.

  20. Global Real-Time Nowcasting of Ionosphere with Giro-Driven Assimilative IRI

    NASA Astrophysics Data System (ADS)

    Galkin, I. A.; Reinisch, B. W.; Huang, X. A.; Vesnin, A.; Bilitza, D.; Song, P.

    2014-12-01

    Real-time prediction of the ionosphere beyond its quiet-time median behavior has proved to be a great challenge: low-latency sensor data streams are scarce, and early comparisons conducted within the CEDAR ETI Assessment framework showed that, on average, the assimilative physics-based models perform on par with the long-term empirical predictions. This rather surprising result led to the formation of the Real-Time Task Force of the International Reference Ionosphere (IRI) science team in 2011, with a simple objective to develop a method for correcting the IRI long-term climatology definitions on the fly, i.e., in near real-time, using suitable observations. Three years later, a pilot version of the IRI-based Real-Time Assimilative Model "IRTAM" started its continuous operations at the Global Ionosphere Radio Observatory (GIRO) Data Center, using online feeds from the ionosondes contributing data to GIRO. The IRTAM version 0.1B builds and publishes every 15-minutes an updated "global weather" map of the peak density and height in the ionosphere, as well as a map of deviations from the classic IRI climate. Incidentally, the IRTAM verification and validation efforts shed light on the forecasting capabilities of the assimilative IRI extension, even though it has not yet involved external activity indicators. At the core of the assimilative computations, a Non-linear Error Compensation Technique for Associative Restoration (NECTAR) seeks agreement between IRI prediction and the 24-hour history of latest observations at GIRO sensor sites to produce the one map frame. The NECTAR first evaluates the diurnal harmonics of the observed deviations from the IRI climatology at each GIRO site to then independently compute the spatial maps for each diurnal harmonic. Thus obtained "corrective" coefficients of the spatial-diurnal expansion are added to the original IRI set of coefficients to obtain the IRTAM specification. We are intrigued by the IRTAM capability to glean

  1. Airborne laser topographic mapping results

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Collins, J. G.; Link, L. E.; Swift, R. N.; Butler, M. L.

    1984-01-01

    The results of terrain mapping experiments utilizing the National Aeronautics and Space Administration (NASA) Airborne Oceanographic Lidar (AOL) over forested areas are presented. The flight tests were conducted as part of a joint NASA/U.S. Army Corps of Engineers (CE) investigation aimed at evaluating the potential of an airborne laser ranging system to provide cross-sectional topographic data on flood plains that are difficult and expensive to survey using conventional techniques. The data described in this paper were obtained in the Wolf River Basin located near Memphis, TN. Results from surveys conducted under winter 'leaves off' and summer 'leaves on' conditions, aspects of day and night operation, and data obtained from decidous and coniferous tree types are compared. Data processing techniques are reviewed. Conclusions relative to accuracy and present limitations of the AOL, and airborne lidar systems in general, to terrain mapping over forested areas are discussed.

  2. An airborne isothermal haze chamber

    NASA Technical Reports Server (NTRS)

    Hindman, E. E.

    1981-01-01

    Thermal gradient diffusion cloud chambers (TGDCC) are used to determine the concentrations of cloud condensation nuclei (CCN) with critical supersaturations greater than or equal to about 0.2%. The CCN concentrations measured with the airborne IHC were lower than theoretically predicted by factors ranging between 7.9 and 9.0. The CCN concentrations measured with the airborne IHC were lower than the concentrations measured with the larger laboratory IHC's by factors ranging between 3.9 and 7.5. The bounds of the supersaturation ranges of the airborne IHC and the CSU-Mee TGDCC do not overlap. Nevertheless, the slopes of the interpolated data between the bounds agree favorably with the theoretical slopes.

  3. WESTERN AIRBORNE CONTAMINANTS ASSESSMENT PROJECT RESEARCH PLAN

    EPA Science Inventory

    The goal of the Western Airborne Contaminants Assessment Project (WACAP) is to assess the deposition of airborne contaminants in Western National Parks, providing regional and local information on exposure, accumulation, impacts, and probable sources. This project is being desig...

  4. Tightly coupled integration of ionosphere-constrained precise point positioning and inertial navigation systems.

    PubMed

    Gao, Zhouzheng; Zhang, Hongping; Ge, Maorong; Niu, Xiaoji; Shen, Wenbin; Wickert, Jens; Schuh, Harald

    2015-01-01

    The continuity and reliability of precise GNSS positioning can be seriously limited by severe user observation environments. The Inertial Navigation System (INS) can overcome such drawbacks, but its performance is clearly restricted by INS sensor errors over time. Accordingly, the tightly coupled integration of GPS and INS can overcome the disadvantages of each individual system and together form a new navigation system with a higher accuracy, reliability and availability. Recently, ionosphere-constrained (IC) precise point positioning (PPP) utilizing raw GPS observations was proven able to improve both the convergence and positioning accuracy of the conventional PPP using ionosphere-free combined observations (LC-PPP). In this paper, a new mode of tightly coupled integration, in which the IC-PPP instead of LC-PPP is employed, is implemented to further improve the performance of the coupled system. We present the detailed mathematical model and the related algorithm of the new integration of IC-PPP and INS. To evaluate the performance of the new tightly coupled integration, data of both airborne and vehicle experiments with a geodetic GPS receiver and tactical grade inertial measurement unit are processed and the results are analyzed. The statistics show that the new approach can further improve the positioning accuracy compared with both IC-PPP and the tightly coupled integration of the conventional PPP and INS. PMID:25763647

  5. NASA capabilities roadmap: advanced telescopes and observatories

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee D.

    2005-01-01

    The NASA Advanced Telescopes and Observatories (ATO) Capability Roadmap addresses technologies necessary for NASA to enable future space telescopes and observatories collecting all electromagnetic bands, ranging from x-rays to millimeter waves, and including gravity-waves. It has derived capability priorities from current and developing Space Missions Directorate (SMD) strategic roadmaps and, where appropriate, has ensured their consistency with other NASA Strategic and Capability Roadmaps. Technology topics include optics; wavefront sensing and control and interferometry; distributed and advanced spacecraft systems; cryogenic and thermal control systems; large precision structure for observatories; and the infrastructure essential to future space telescopes and observatories.

  6. SOFIA Observatory Obtains 'First Light' Images

    NASA Video Gallery

    NASA's Stratospheric Observatory for Infrared Astronomy, or SOFIA, successfully obtained its "First Light"" images during an overnight flight May 26. Scientists are now processing the data gathered...

  7. The Uncertain Future of Arecibo Observatory

    NASA Astrophysics Data System (ADS)

    Altschuler, D. R.

    2009-05-01

    After forty years of existence, Arecibo Observatory has an uncertain future. On November 3th, 2006 the ``Senior Review'' (SR), an advisory panel, recommended to the astronomy division of NSF that the anual budget destinated to astronomy in the Observatory, should be reduced from US10.5 million annual to US8 million during the first 3 years. The SR also indicated that the Observatory have to be closed in 2011, if an external financial source is not found. The SR panel was called to find near US30 million in savings (approximately 25% of total budget of the five national observatories, including Arecibo) to redirect them to operate new future projects.

  8. A new Magnetic Observatory in Pantanal - Brazil

    NASA Astrophysics Data System (ADS)

    Siqueira, F.; Pinheiro, K.; Linthe, H.

    2013-05-01

    The aim of a Magnetic Observatory is to register the variations of the Earth's magnetic field in a long temporal scale. Using this data it is possible to study field variations of both external and internal origins. The external variations concern interactions between the magnetosphere and the solar wind, in general are measured in a short time scale. The internal field generated by convection of a high electrical conductivity fluid in the external core by a mechanism known as the geodynamo. Usually the internal field time variations are longer than in the external field and are called secular variations. Measurements carried out over the last century suggest that field intensity is decreasing rapidly. The decreasing of the field's intensity is not the same around the globe, especially at the SAMA (South Atlantic Magnetic Anomaly) regions, where this reduction is occurring faster. The global distribution of magnetic observatories is uneven, with few observatories in South America. In Brazil, there are three magnetic observatories, but only Vassouras Observatory (VSS- RJ) is part of the INTERMAGNET network. The National Observatory has plans to install seven new observatories in Brazil. Pantanal was the chosen location for installing the first observatory because of its privileged location, close to the SAMA region, and its data can contribute to more information about its origin. We followed the procedures suggested by the IAGA to build this observatory. The first step is to perform a magnetic survey in order to avoid strong magnetic gradients in the location where the absolute and variometers houses will be installed. The next step, the construction of the observatory, includes the selection of special non-magnetic material for the variometer and absolute houses. All materials used were previously tested using a proton magnetometer GSM-19. After construction of the whole infrastructure, the equipment was installed. This Project is a cooperation between Brazilian

  9. Simulation of the Mars Ionosphere Radio Occultation Experiments

    NASA Astrophysics Data System (ADS)

    Hu, X.; Wu, X. C.; Gong, X. Y.; Wang, X.; Xu, Q. C.

    2009-07-01

    The Mars ionosphere radio occultation experiment between the Chinese YH-1 spacecraft and the Russian Phobos-Grunt spacecraft orbiting Mars will be the first satellite to satellite radio occultation experiment in history, which will achieve high quality ionospheric electron density profiles. The technique used in this experiment is analyzed and introduced. Simulations of the radio occultation have been completed. Forward calculations of the radio wave observable for the ionospheric radio occultation events have been done with the 3D ray tracing method and a simple Chapman ionosphere background model. The backward inversion with the forward calculated radio occultation observation data gives reliable and consistent ionospheric electron density profiles, which show the reliability of the simulation algorithms. With the simulation method, the effects of errors from the radio signal phase measurement and the orbit determination of the satellite on the inversion are analyzed in cases. Results show that phase errors of 5% circle have a negligible effect on the daytime ionosphere radio occultation, and lead to an absolute error of less than 4×;10^8 m3 for nighttime electron density profiles. Orbit errors of the satellite mainly pose a systematic rising or descending to the ionosphere height. The above results show that Sino-Russian cooperative Mars ionosphere radio occultation experiments is expected to achieve high quality Mars ionosphere profiles. Their technique regime can be used for the lunar ionosphere exploring.

  10. Calculation of Precipitable Water for Stratospheric Observatory for Infrared Astronomy Aircraft (SOFIA): Airplane in the Night Sky

    NASA Technical Reports Server (NTRS)

    Wen, Pey Chun; Busby, Christopher M.

    2011-01-01

    Stratospheric Observatory for Infrared Astronomy, or SOFIA, is the new generation airborne observatory station based at NASA s Dryden Aircraft Operations Facility, Palmdale, CA, to study the universe. Since the observatory detects infrared energy, water vapor is a concern in the atmosphere due to its known capacity to absorb infrared energy emitted by astronomical objects. Although SOFIA is hoping to fly above 99% of water vapor in the atmosphere it is still possible to affect astronomical observation. Water vapor is one of the toughest parameter to measure in the atmosphere, several atmosphere modeling are used to calculate water vapor loading. The water vapor loading, or Precipitable water, is being calculated by Matlab along the planned flight path. Over time, these results will help SOFIA to plan flights to regions of lower water vapor loading and hopefully improve the imagery collection of these astronomical features.

  11. Airborne Transmission of Bordetella pertussis

    PubMed Central

    Warfel, Jason M.; Beren, Joel; Merkel, Tod J.

    2012-01-01

    Pertussis is a contagious, acute respiratory illness caused by the bacterial pathogen Bordetella pertussis. Although it is widely believed that transmission of B. pertussis occurs via aerosolized respiratory droplets, no controlled study has ever documented airborne transmission of pertussis. We set out to determine if airborne transmission occurs between infected and naive animals, utilizing the baboon model of pertussis. Our results showed that 100% of exposed naive animals became infected even when physical contact was prevented, demonstrating that pertussis transmission occurs via aerosolized respiratory droplets. PMID:22807521

  12. NASA Airborne Lidar 1982-1984 Flights

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar 1982-1984 Flights Data from the 1982 NASA Langley Airborne Lidar flights following the eruption of El Chichon ... continuing to January 1984. Transcribed from the following NASA Tech Reports: McCormick, M. P., and M. T. Osborn, Airborne lidar ...

  13. Virtual Energetic Particle Observatory (VEPO)

    NASA Astrophysics Data System (ADS)

    Cooper, J. F.; Lal, N.; McGuire, R. E.; Szabo, A.; Narock, T. W.; Armstrong, T. P.; Manweiler, J. W.; Patterson, J. D.; Hill, M. E.; Vandergriff, J. D.; McKibben, R. B.; Lopate, C.; Tranquille, C.

    2008-12-01

    The Virtual Energetic Particle Observatory (VEPO) focuses on improved discovery, access, and usability of heliospheric energetic particle and ancillary data products from selected spacecraft and sub-orbital instruments of the heliophysics data environment. The energy range of interest extends over the full range of particle acceleration from keV energies of suprathermal seed particles to GeV energies of galactic cosmic ray particles. Present spatial coverage is for operational and legacy spacecraft operating from the inner to the outer heliosphere, e.g. from measurements by the two Helios spacecraft to 0.3 AU to the inner heliosheath region now being traversed by the two Voyager spacecraft. This coverage will eventually be extended inward to ten solar radii by the planned NASA solar probe mission and at the same time beyond the heliopause into the outer heliosheath by continued Voyager operations. The geospace fleet of spacecraft providing near-Earth interplanetary measurements, selected magnetospheric spacecraft providing direct measurements of penetrating interplanetary energetic particles, and interplanetary cruise measurements from planetary spacecraft missions further extend VEPO resources to the domain of geospace and planetary interactions. Ground-based (e.g., neutron monitor) and high-altitude suborbital measurements can expand coverage to the highest energies of galactic cosmic rays affected by heliospheric interaction and of solar energetic particles. Science applications include investigation of solar flare and coronal mass ejection events, acceleration and transport of interplanetary particles within the inner heliosphere, cosmic ray interactions with planetary surfaces and atmospheres, sources of suprathermal and anomalous cosmic ray ions in the outer heliosphere, and solar cycle modulation of galactic cosmic rays. Robotic and human exploration, and eventual habitation, of planetary and space environments beyond the Earth require knowledge of radiation

  14. Virtual Energetic Particle Observatory (VEPO)

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Lal, Nand; McGuire, Robert E.; Szabo, Adam; Narock, Thomas W.; Armstrong, Thomas P.; Manweiler, Jerry W.; Patterson, J. Douglas; Hill, Matthew E.; Vandergriff, Jon D.; McKibben, Robert B.; Lopate, Clifford; Tranquille, Cecil

    2008-01-01

    The Virtual Energetic Particle Observatory (VEPO) focuses on improved discovery, access, and usability of heliospheric energetic particle and ancillary data products from selected spacecraft and sub-orbital instruments of the heliophysics data environment. The energy range of interest extends over the full range of particle acceleration from keV energies of suprathermal seed particles to GeV energies of galactic cosmic ray particles. Present spatial coverage is for operational and legacy spacecraft operating from the inner to the outer heliosphere, e.g. from measurements by the two Helios spacecraft to 0.3 AU to the inner heliosheath region now being traversed by the two Voyager spacecraft. This coverage will eventually be extended inward to ten solar radii by the planned NASA solar probe mission and at the same time beyond the heliopause into the outer heliosheath by continued Voyager operations. The geospace fleet of spacecraft providing near-Earth interplanetary measurements, selected magnetospheric spacecraft providing direct measurements of penetrating interplanetary energetic particles, and interplanetary cruise measurements from planetary spacecraft missions further extend VEPO resources to the domain of geospace and planetary interactions. Ground-based (e.g., neutron monitor) and high-altitude suborbital measurements can expand coverage to the highest energies of galactic cosmic rays affected by heliospheric interaction and of solar energetic particles. Science applications include investigation of solar flare and coronal mass ejection events. acceleration and transport of interplanetary particles within the inner heliosphere, cosmic ray interactions with planetary surfaces and atmospheres, sources of suprathermal and anomalous cosmic ray ions in the outer heliosphere, and solar cycle modulation of galactic cosmic rays. Robotic and human exploration, and eventual habitation, of planetary and space environments beyond the Earth require knowledge of radiation

  15. A Technical Overview and Description of SOFIA (Stratospheric Observatory for Infrared Astronomy)

    NASA Technical Reports Server (NTRS)

    Kunz, Nans

    2003-01-01

    This paper provides a technical overview of SOFIA, a unique airborne observatory, from an engineering perspective. It will do this by describing several of the systems of this observatory that are common with mountain top ground based observatories but mostly emphasize those more unique features and systems that are required to facilitate world class astronomy from a highly modified Boeing 747-SP flying at Mach 0.84 in the Stratosphere. This paper provides a technical overview of SOFIA by reviewing each of the performance specifications (the level one requirements for development) and describing some of the technical advancements for the telescope as well as the platform required to achieve these performance specifications. The technical advancements involved include mirror technologies, control system features, the telescope suspension system, and the aircraft open port cavity with associated cavity door that opens in flight and tracks the telescope elevation angle. For background this paper will provide a brief programmatic overview of the SOFIA project including the joint project arrangement between the US and Germany (NASA and DLR). Additionally, this paper will describe the up to date status of the development of SOFIA as the Observatory nears the date of the first test flight in the summer of 2004.

  16. Airborne astronomy with a 150 micrometer - 500 micrometer heterodyne spectrometer

    NASA Technical Reports Server (NTRS)

    Betz, A. L.

    1991-01-01

    This report summarizes work done under NASA Grant NAG2-254 awarded to the University of California. The project goal was to build a far-infrared heterodyne spectrometer for NASA's Kuiper Airborne Observatory (KAO), and to use this instrument to observe atomic and molecular spectral lines from the interstellar medium. This goal was successfully achieved; the spectrometer is now in routine use aboard the KAO. Detections of particular note have been the 370 micrometers line of neutral atomic carbon, the 158 micrometers transition of ionized carbon, many of the high-J rotational lines of 12CO and 13CO between J=9-8 and J=22-21, the 119 micron ground-state rotational line of OH, and the 219 micron ground-state rotational line of H2D(+). All of these lines were observed at spectral resolutions exceeding 1 part in 10(exp 6), thereby allowing accurate line shapes and Doppler velocities to be measured.

  17. Airborne spectrophotometry of Comet Halley from 5 to 9 microns

    NASA Technical Reports Server (NTRS)

    Campins, H.; Bregman, J. D.; Witteborn, F. C.; Wooden, D. H.; Rank, D. M.; Cohen, M.; Allamandola, Louis J.; Tielens, Alexander G. G. M.

    1986-01-01

    Spectrophotometry from 5 to 9 microns (resolution = 0.02) of comet Halley was obtained from the Kuiper Airborne Observatory on 1985 Dec. 12.1 and 1986 April 8.6 and 10.5 UT. Two spectral features are apparent in all the observations, one from 5.24 to 5.6 microns, and the silicate emission feature which has an onset between 7 and 8 microns. There is no evidence for the 7.5 microns feature observed by the Vega 1 spacecraft; the large difference between the areal coverage viewed from the spacecraft and the airplane may explain the discrepancy. Color temperatures significantly higher than a blackbody indicate that small particles are abundant in the coma. Significant spatial and temporal variations in the spectrum show trends similar to those observed from the ground.

  18. Vertical and oblique ionospheric soundings over the long haul HF link between Antarctica and Spain

    NASA Astrophysics Data System (ADS)

    Ads, A. G.; Bergadà, P.; Regué, J. R.; Alsina-Pagès, R. M.; Pijoan, J. L.; Altadill, D.; Badia, D.; Graells, S.

    2015-09-01

    This paper presents a comparative study between the oblique sounding results, the International Telecommunication Union Rec533 HF prediction model, and the vertical sounding results of a transequatorial long haul link. The long haul link is a 12,760 km link between the Spanish Antarctic Station, SAS, located in the Livingston Island and the Ebro Observatory (OE) in Spain. The data were collected during three consecutive surveys (2009/2010, 2010/2011, and 2011/2012). The ionospheric channel from the SAS to the OE is studied in terms of frequency availability as function of time using the measurements of an oblique incidence sounder (OIS) and measurements of several vertical incidence sounding stations (VIS) placed near the estimated radiopropagation path. The results obtained show promising correlations between VIS and OIS measurements and led us to think that the frequency of largest availability for this particular long haul radio link can be estimated from the VIS sounding measurements.

  19. The Virtual Wave Observatory (VWO)

    NASA Astrophysics Data System (ADS)

    Fung, S. F.; VWO Team

    2008-12-01

    Heliophysics wave data are currently not easily searchable by computers, making identifying pertinent wave data features for analyses and cross comparisons difficult and laborious. Since wave data analysis requires specialized knowledge about waves, which spans the spectrum of microphysics to macrophysics, researchers having varied expertise cannot easily use wave data. To resolve these difficulties and to allow wave data to contribute more fully to Heliophysics research, we are developing a Virtual Wave Observatory (VWO) whose goal is to enable all Heliophysics wave data to become searchable, understandable and usable by the Heliosphysics community. The VWO objective is to enable search of multiple and distributed wave data (from both active and passive measurements). This presentation provides and overview of the VWO, a new VxO component within the emerging distributed Heliophysics data and model environment.

  20. Autonomous Infrastructure for Observatory Operations

    NASA Astrophysics Data System (ADS)

    Seaman, R.

    This is an era of rapid change from ancient human-mediated modes of astronomical practice to a vision of ever larger time domain surveys, ever bigger "big data", to increasing numbers of robotic telescopes and astronomical automation on every mountaintop. Over the past decades, facets of a new autonomous astronomical toolkit have been prototyped and deployed in support of numerous space missions. Remote and queue observing modes have gained significant market share on the ground. Archives and data-mining are becoming ubiquitous; astroinformatic techniques and virtual observatory standards and protocols are areas of active development. Astronomers and engineers, planetary and solar scientists, and researchers from communities as diverse as particle physics and exobiology are collaborating on a vast range of "multi-messenger" science. What then is missing?