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Sample records for advanced ionospheric sounder

  1. Topside Ionospheric Sounder for CubeSats

    NASA Astrophysics Data System (ADS)

    Swenson, C.; Pratt, J.; Fish, C. S.; Winkler, C.; Pilinski, M.; Azeem, I.; Crowley, G.; Jeppesen, M.; Martineau, R.

    2014-12-01

    This presentation will outline the design of a Topside Ionospheric Sounder (TIS) for CubeSats. In the same way that an ionosonde measures the ionospheric profile from the ground, a Topside Sounder measures the ionospheric profile from a location above the F-region peak. The TIS will address the need for increased space situational awareness and environmental monitoring by estimating electron density profiles in the topside of the ionosphere. The TIS will measure topside electron density profiles for plasma frequencies ranging from 0.89 MHz to 28.4 MHz below the satellite altitude. The precision of the measurement will be 5% or 10,000 p/cm^3. The TIS average power consumption will be below 10 W and a mass of less than 10 kg, so it is appropriate for a 6U Cubesat (or multiple of that size). The sounder will operate via a transmitted frequency sweep across the desired plasma frequencies which, upon reception, can be differenced to determine range and density information of the topside ionosphere. The velocity of the spacecraft necessitates careful balancing of range resolution and frequency knowledge requirements as well as novel processing techniques to correctly associate the return signal with the correct plasma frequency. TIS is being designed to provide a low cost, low mass spacecraft that can provide accurate topside profiles of the ionospheric electron density in order to further understanding of ionospheric structure and dynamic processes in the ionosphere.

  2. Topside sounders as mobile ionospheric heaters

    NASA Technical Reports Server (NTRS)

    Benson, R. F.

    2006-01-01

    There is evidence that satellite-borne RF sounders can act as mobile ionospheric heaters in addition to performing topside sounding. The main objective of topside sounding is to use sounder-generated electromagnetic (em) waves to obtain ionospheric topside vertical electron-density (N(sub e) profiles. These profiles are obtained from mathematical inversions of the frequency vs. delay-time ionospheric reflection traces. In addition to these em reflection traces, a number of narrowband intense signals are observed starting at zero delay times after the transmitted pulses. Some of these signals, termed plasma resonances, appear at characteristic frequencies of the ambient medium such as at the electron cyclotron frequency f(sub ce), the harmonics nf(sub ce), the electron plasma frequency f(sub pe) and the upper-hybrid frequency f(sub uh), where (f(sub uh))(exp 2) = (f(sub ce))(exp 2) + (f(sub pe))(exp 2) . These signals have been attributed to the oblique echoes of sounder-generated electrostatic (es) waves. These resonances provide accurate in situ f(sub pe) and f(sub ce) values which, in turn, lead to accurate N(sub e) and [B] values where B is the ambient magnetic field. Resonances are also observed between the nf(sub ce) harmonics both above and below f(sub uh). The former, known as the Qn plasma resonances, are mainly attributed to the matching of the wave group velocity of sounder-generated (Bernstein-mode) es waves to the satellite velocity. The frequency spectrum of these waves in the magnetosphere can be used to detect non-Maxwellian electron velocity-distributions. In addition, these resonances also exhibit components that appear to be the result of plasma emissions stimulated by the sounder pulses. The plasma resonances observed between the nf(sub ce) harmonics and below f(sub uh), known as the Dn plasma resonances, are entirely attributed to such sounder-stimulated plasma emissions. There are other sounder-stimulated plasma phenomena that also fall into

  3. Results of the international ionospheric Doppler sounder network

    NASA Astrophysics Data System (ADS)

    Lastovicka, Jan; Chum, Jaroslav

    2016-07-01

    This paper summarizes main recent results reached by the Czech-lead international network of ionospheric Doppler sounders. The network consists of Doppler sounders in the western half of Czechia (5 measuring paths, 3 frequencies with central receivers in Prague), northern Taiwan (3 transmitters, two separated receivers, 1 frequency), and three similar systems (3 measuring paths with 1 receiver and 1 frequency) in Tucuman (north-western Argentina), Hermanus (the southernmost South Africa) and Luisville (northern South Africa). Three main areas of research have been (1) statistical properties of gravity waves, (2) ionospheric effects of earthquakes, and (3) low latitude/equatorial phenomena. Some results: (1) the theoretically expected dominance of gravity wave propagation against wind has been confirmed; (2) impact of the Tohoku 2001 M9.0 earthquake was registered in the ionosphere over the Czech Republic as long-period infrasound on the distance of about 9000 km from epicenter; analysis of ionospheric infrasound excited by the Nepal 2015 M7.8 earthquake observed by the Czech and Taiwan Doppler sounders showed that the intensity of ionospheric signal is significantly height dependent and that the Doppler shift depends not only on the advection (up and down motion) of the reflecting layer but also on the compression/rarefaction of the electron gas; (3) spread F structures observed by Doppler sounders in Tucuman and Taiwan (both under the crest of equatorial ionization anomaly) provide results consistent with S4 scintillation data and with previous optical, GPS and satellite measurements.

  4. The DST group ionospheric sounder replacement for JORN

    NASA Astrophysics Data System (ADS)

    Harris, T. J.; Quinn, A. D.; Pederick, L. H.

    2016-06-01

    The Jindalee Over-the-horizon Radar Network (JORN) is an integral part of Australia's national defense capability. JORN uses a real-time ionospheric model as part of its operations. The primary source of data for this model is a set of 13 vertical-incidence sounders (VIS) scattered around the Australian coast and inland locations. These sounders are a mix of Lowell digisonde portable sounder (DPS)-1 and DPS-4. Both of these sounders, the DPS-1 in particular, are near the end of their maintainable life. A replacement for these aging sounders was required as part of the ongoing sustainment program for JORN. Over the last few years the High-Frequency Radar Branch (HFRB) of the Defence Science and Technology (DST) Group, Australian Department of Defence, has been developing its own sounders based on its successful radar hardware technology. The DST Group VIS solution known as PRIME (Portable Remote Ionospheric Monitoring Equipment) is a 100% duty cycle, continuous wave system that receives the returned ionospheric signal while it is still transmitting and operates the receiver in the near field of the transmitter. Of considerable importance to a successful VIS is the autoscaling software, which takes the ionogram data and produces an ionogram trace (group delay as a function of frequency), and from that produces a set of ionospheric parameters that represent the (bottomside) overhead electron density profile. HFRB has developed its own robust autoscaling software. The performance of DST Group's PRIME under a multitude of challenging ionospheric conditions has been studied. In December 2014, PRIME was trialed at a JORN VIS site collocated with the existing Lowell Digisonde DPS-1. This side-by-side testing determined that PRIME was fit for purpose. A summary of the results of this comparison and example PRIME output will be discussed. Note that this paper compares PRIME with the 25 year old Lowell Digisonde DPS-1, which is planned to be replaced. Our future plans include

  5. Advanced Atmospheric Sounder and Imaging Radiometer (AASIR)

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Design information for the Advanced Atmospheric Sounder and Imaging Radiometer is reported, which was developed to determine the configuration of a sensor for IR and visible imaging. The areas of technology reported include: systems design, optics, mechanics, electronics, detectors, radiative cooler, and radiometric calibration.

  6. A study of travelling ionospheric disturbances over Macquarie Island using an oblique CW sounder

    NASA Astrophysics Data System (ADS)

    Beggs, H. M.; Butcher, E. C.

    1989-08-01

    From April to October 1987 an oblique ionospheric sounder was deployed on Macquarie Island in order to study F-region traveling ionospheric disturbances in the southern auroral region. The signal strength and change in phase path of the received 3.399 MHz continuous signal were recorded digitally, and dynamic power spectra produced using the maximum entropy method. Interesting results for daytime traveling ionospheric disturbances for May-August 1987 have been obtained. Many data records illustrated a strong correlation between oscillations in the phase path and the received amplitude of the sounding signal, as predicted for a sinusoidal ionospheric reflector model.

  7. Solar control of the Martian Ionosphere as Detected by MARSIS Active Ionospheric Sounder

    NASA Astrophysics Data System (ADS)

    Morgan, D. D.; Gurnett, D. A.; Kirchner, D. L.; Fox, J. L.; Nielsen, E.; Plaut, J. J.; Picardi, G.

    2007-12-01

    The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), aboard the ESA spacecraft Mars Express, was deployed 17 June 2005 and commissioned in July 2005. MARSIS includes an Active Ionospheric Sounding (AIS) mode, which targets the topside ionosphere of Mars. Between August 2005 and July 2007, the spacecraft performed approximately 2500 orbits. From these orbits we have selected for analysis some 30,000 ionograms, about one-half of which were acceptable for inversion to an electron density profile. We bin these data by various quantities and plot the peak plasma densities and their corresponding altitudes from each bin as a function of solar zenith angle. Each plot can then be fit to a Chapman model to determine characteristic values of the subsolar plasma density peak, subsolar density peak altitude, and neutral scale height for that bin. The results from each bin can then be plotted as a function of the binned quantity to infer trends in the martian ionosphere. We detect an increase in electron density in the martian ionosphere with solar activity as indexed by F10.7 flux and XUV flux from SORCE XPS, both corrected for the changing distance of Mars from the Sun. We see an average change of about 6% in the subsolar peak electron density and a 6 km increase in the subsolar peak density altitude during periods when we can infer the presence of solar energetic particles from MARSIS AIS surface reflection data. We also see variation in the Chapman parameters due to seasonal and areodetic variation. In particular, at high latitudes near the summer solstice in both northern and southern hemispheres, we note an increase in the neutral scale height and decrease in the electron density peak altitude.

  8. Spectral Resolution and Coverage Impact on Advanced Sounder Information Content

    NASA Technical Reports Server (NTRS)

    Larar, Allen M.; Liu, Xu; Zhou, Daniel K.; Smith, William L.

    2010-01-01

    Advanced satellite sensors are tasked with improving global measurements of the Earth s atmosphere, clouds, and surface to enable enhancements in weather prediction, climate monitoring capability, and environmental change detection. Achieving such measurement improvements requires instrument system advancements. This presentation focuses on the impact of spectral resolution and coverage changes on remote sensing system information content, with a specific emphasis on thermodynamic state and trace species variables obtainable from advanced atmospheric sounders such as the Infrared Atmospheric Sounding Interferometer (IASI) and Cross-track Infrared Sounder (CrIS) systems on the MetOp and NPP/NPOESS series of satellites. Key words: remote sensing, advanced sounders, information content, IASI, CrIS

  9. TIDs in the Bottomside Ionospheric F-region Observed Near Jicamarca Using the TIDDBIT HF Doppler Sounder

    NASA Astrophysics Data System (ADS)

    Crowley, G.; Chau, J. L.

    2012-12-01

    The equatorial ionosphere is the site of complex interactions between various geospace drivers, including thermospheric winds, electric fields, and tides propagating from below. Less well known is the effect of gravity waves, and their manifestation as traveling ionospheric disturbances (TIDs). HF Doppler sounders represent a low-cost and low-maintenance solution for monitoring wave activity in the F region ionosphere. Together with modern data analysis techniques, they can provide comprehensive TID characteristics, including both horizontal and vertical TID velocities and wavelengths across the entire spectrum from periods of 1 min to over an hour. In this invited talk, we review some of the previous observations of TIDs at low latitudes, and present new observations from the TIDDBIT HF Doppler Sounder recently developed by Atmospheric and Space Technology Research Associates LLC, and deployed at Jicamarca, Peru. The completeness of the wave information obtained from the TIDDBIT system makes it possible to reconstruct the vertical displacement of isoionic contours over the 200 km horizontal dimension of the sounder array, and movies revealing the detailed shape and motion of isoionic surfaces over Peru will be shown. We demonstrate how the TID characteristics in Peru vary with season and magnetic activity. We discuss their possible impact on triggering of ionospheric bubbles and irregularities. Such information will be relevant for various operational needs involving navigation, communication, and surveillance systems. Crowley G., and F.S. Rodrigues (2012), Characteristics of Traveling Ionospheric Disturbances Observed by the TIDDBIT Sounder, Radio Sci., doi:10.1029/2011RS004959.

  10. Ducted electromagnetic waves in the Martian ionosphere detected by the Mars Advanced Radar for Subsurface and Ionosphere Sounding radar

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenfei; Orosei, Roberto; Huang, Qian; Zhang, Jie

    2016-07-01

    In the data of the Mars Advanced Radar for Subsurface and Ionosphere Sounding on board the European Space Agency (ESA) mission Mars Express (MEX), a distinctive type of signals (called the "epsilon signature"), which is similar to that previously detected during radio sounding of the terrestrial F region ionosphere, is found. The signature is interpreted to originate from multiple reflections of electromagnetic waves propagating along sounder pulse-created, crustal magnetic field-aligned plasma bubbles (waveguides). The signatures have a low (below 0.5%) occurrence rate and apparent cutoff frequencies 3-5 times higher than the theoretical one for an ordinary mode wave. These properties are explained by the influence of the perpendicular ionospheric plasma density gradient and the sounder pulse frequency on the formation of waveguides.

  11. Effect of HF Emission of the topside sounder transmitter aboard the COSMOS-1809 satellite on the ionospheric plasma

    NASA Astrophysics Data System (ADS)

    Baranets, N. V.; Gladyshev, V. A.; Afonin, V. V.

    The experiment on investigation of effect of the HF emission (300 W) by the dipole antenna on the ionospheric plasma was carried out onboard the COSMOS-1809 satellite (1987). The sounder accelerated particles (SAP) at the electron cyclotron harmonics n x omegace and in the frequency region of antenna resonance were detected by the charged particle spectrometer.

  12. Geophysical Information from Advanced Sounder Infrared Spectral Radiance

    NASA Technical Reports Server (NTRS)

    Larar, Allen M.; Zhou, Daniel K.; Liu, Xu; Smith, William L.

    2012-01-01

    Advanced satellite sensors are tasked with improving global observations of the Earth's atmosphere, clouds, and surface to enable enhancements in weather prediction, climate monitoring capability, and environmental change detection. Satisfying this type of improvement for inferred geophysical information from these observations requires optimal usage of data from current systems as well as enhancements to future sensors. This presentation addresses the information content present in infrared spectral radiance from advanced atmospheric sounders with an emphasis on knowledge of thermodynamic state and trace species. Results of trade-off studies conducted to evaluate the impact of spectral resolution, spectral coverage, instrument noise, and a priori knowledge on remote sensing system information content will be discussed. A focus is placed on information achievable from the Atmospheric InfraRed Sounder (AIRS) on the NASA EOS Aqua satellite in orbit since 2002, the Infrared Atmospheric Sounding Interferometer (IASI) aboard MetOp-A since 2006, and the Cross-track Infrared Sounder (CrIS) instrument aboard the NPP and JPSS series of satellites which began 28 October 2011.

  13. Ionospheric tsunami disturbances probed by HF Doppler sounder, ionosonde and ground-based GPS TEC

    NASA Astrophysics Data System (ADS)

    Chen, Wei-Suan; Liu, Jann-Yenq Tiger; Wu, Tso-Ren; Tsai, Yu-Lin

    2016-04-01

    Tsunami waves induced by the 26 December 2004 Mw 9.3 Sumatra earthquake, the 11 March 2011 Mw 9.0 Tohoku earthquake, and the 16 September 2015 Mw 8.2 Chile earthquake are recorded by tide gauges around Taiwan. In this paper, the tsunami waves are studied by the tide gauge data and Cornell Multi-grid Coupled of Tsunami Model (COMCOT) simulations, while ionospheric tsunami disturbances (ITDs) are probed by the HF Doppler sounder with a sounding frequency of 5.26 MHz, ionosonde, and GPS TEC derived by ground-based GPS receivers in Taiwan. It is found that ITDs tend to lead their associated tsunami by about 30-60 minutes. A comparison between ITDs and tsunami waves will be presented and discussed.

  14. HF doppler sounder measurements of the ionospheric signatures of small scale ULF waves

    NASA Astrophysics Data System (ADS)

    Baddeley, L. J.; Yeoman, T. K.; Wright, D. M.

    2005-07-01

    An HF Doppler sounder, DOPE (DOppler Pulsation Experiment) with three azimuthally-separated propagation paths is used to provide the first statistical examination of small scale-sized, high m waves where a direct measurement of the azimuthal wavenumber m, is made in the ionosphere. The study presents 27 events, predominantly in the post-noon sector. The majority of events are Pc4 waves with azimuthal m numbers ranging from 100 to 200, representing some of the smallest scale waves ever observed in the ionosphere. 4 Pc5 waves are observed in the post-noon sector. The fact that measurements for the wave azimuthal m number and the wave angular frequency are available allows the drift-bounce resonance condition to be used to hypothesise potential particle populations which could drive the waves through either a drift or drift-bounce resonance interaction mechanism. These results are compared with the statistical study presented by Baddeley et al. (2004) which investigated the statistical likelihood of such driving particle populations occurring in the magnetospheric ring current. The combination of these two studies indicates that any wave which requires a possible drift resonance interaction with particles of energies >60 keV, is statistically unlikely to be generated by such a mechanism. The evidence presented in this paper therefore suggests that in the pre-noon sector the drift-bounce resonance mechanism is statistically more likely implying an anti-symmetric standing wave structure while in the post-noon sector both a drift or drift-bounce resonance interaction is statistically possible, indicating both symmetric and anti-symmetric standing mode structures. A case study is also presented investigating simultaneous observations of a ULF wave in ground magnetometer and DOPE data. The event is in the lower m range of the statistical study and displays giant pulsation (Pg) characteristics. Keywords. Ionosphere (Ionosphere-magnetosphere interactions) Magnetospheric

  15. Estimation of the Total Electron Content of the Martian Ionosphere using Radar Sounder Surface Echoes

    NASA Technical Reports Server (NTRS)

    Safaeinili, Ali; Kofman, Wlodek; Mouginot, Jeremie; Gim, Yonggyu; Herique, Alain; Ivanov, Anton B.; Plaut, Jeffrey J.; Picardi, Giovanni

    2007-01-01

    The Martian ionosphere's local total electron content (TEC) and the neutral atmosphere scale height can be derived from radar echoes reflected from the surface of the planet. We report the global distribution of the TEC by analyzing more than 750,000 echoes of the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS). This is the first direct measurement of the TEC of the Martian ionosphere. The technique used in this paper is a novel 'transmission-mode' sounding of the ionosphere of Mars in contrast to the Active Ionospheric Sounding experiment (AIS) on MARSIS, which generally operates in the reflection mode. This technique yields a global map of the TEC for the Martian ionosphere. The radar transmits a wideband chirp signal that travels through the ionosphere before and after being reflected from the surface. The received waves are attenuated, delayed and dispersed, depending on the electron density in the column directly below the spacecraft. In the process of correcting the radar signal, we are able to estimate the TEC and its global distribution with an unprecedented resolution of about 0.1 deg in latitude (5 km footprint). The mapping of the relative geographical variations in the estimated nightside TEC data reveals an intricate web of high electron density regions that correspond to regions where crustal magnetic field lines are connected to the solar wind. Our data demonstrates that these regions are generally but not exclusively associated with areas that have magnetic field lines perpendicular to the surface of Mars. As a result, the global TEC map provides a high-resolution view of where the Martian crustal magnetic field is connected to the solar wind. We also provide an estimate of the neutral atmospheric scale height near the ionospheric peak and observe temporal fluctuations in peak electron density related to solar activity.

  16. Impact of Measurement System Characteristics on Advanced Sounder Information Content

    NASA Technical Reports Server (NTRS)

    Larar, Allen M.; Liu, Xu; Zhou, Daniel K.

    2011-01-01

    Advanced satellite sensors are tasked with improving global observations of the Earth's atmosphere, clouds, and surface to enable enhancements in weather prediction, climate monitoring capability, and environmental change detection. Achieving such an improvement in geophysical information inferred from these observations requires optimal usage of data from current systems as well as instrument system enhancements for future sensors. This presentation addresses results of tradeoff studies evaluating the impact of spectral resolution, spectral coverage, instrument noise, and a priori knowledge on remote sensing system information content, with a specific emphasis on thermodynamic state and trace species information obtainable from advanced atmospheric sounders. Particular attention will be devoted toward information achievable from the Atmospheric InfraRed Sounder (AIRS) on the NASA EOS Aqua satellite in orbit since 2002, the Infrared Atmospheric Sounding Interferometer (IASI) aboard MetOp-A since 2006, and the Cross-track Infrared Sounder (CrIS) instrument to fly aboard the NPP and JPSS series of satellites expected to begin in late 2011. While all of these systems cover nearly the same infrared spectral extent, they have very different number of channels, instrument line shapes, coverage continuity, and instrument noise. AIRS is a grating spectrometer having 2378 discrete spectral channels ranging from about 0.4 to 2.2/cm resolution; IASI is a Michelson interferometer with 8461 uniformly-spaced spectral channels of 0.5/cm (apodized) resolution; and CrIS is a Michelson interferometer having 1305 spectral channels of 0.625, 1.250, and 2.50/cm (unapodized) spectral resolution, respectively, over its three continuous but non-overlapping bands. Results of tradeoff studies showing information content sensitivity to assumed measurement system characteristics will be presented.

  17. Alouette and ISIS topside sounder measurements -A data source for improvements of the IRI model in the topside ionosphere

    NASA Astrophysics Data System (ADS)

    Bilitza, Dieter; Benson, Robert; Reinisch, Bodo; Huang, Xueqin

    The Alouette and ISIS topside sounder satellites recorded a great wealth of information about the topside ionosphere during their long period of operations (from 1962 to 1990). So much though that only a small percentage was analyzed during the mission life time. The soundings were stored on more than 100,000 seven-track analog telemetry tapes. In the mid-nineties space limitations and storage costs threatened an imminent loss of these tapes. Only a last minute intervention spear-headed by NASA's Ionosphere, Thermosphere, Mesosphere (ITM) Data Evaluation Panel saved a significant portion of these tapes and with funding from the AISRP program these data were first digitized and then converted into electron density profiles. This data restoration effort more than tripled the Alouette/ISIS topside sounder data base and has led to significant improvements of models for the topside ionosphere, e.g., about a factor of 2 improvement in the case of the IRI-2007 topside electron density profile. We will present a brief history of this successful data restoration effort and its current status. The homepage for the ISIS project is at http://nssdc.gsfc.nasa.gov/space/isis/isis-status.html.

  18. Two classes of medium-scale traveling ionospheric disturbances observed with an array on HF-Doppler sounders

    NASA Technical Reports Server (NTRS)

    Shibata, T.; Okuzawa, T.

    1985-01-01

    The importance of the quasi-evanescent mode of acoustic-gravity waves (AGW) was recently stressed to elaborate on the daytime dispersion characteristics of horizontal velocity of medium-scale traveling ionospheric disturbances (MS-TID) which were observed by a high frequency Doppler (HFD) sounder array in central Japan. Observed MS-TIDs were classified into two categories: the internal mode and the quasi-evanescent mode as regards physical implication. Nonlinear wave-wave interaction is proposed in an attempt to explain salient features of the latter-class TID.

  19. 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.

  20. Characteristics of TIDs Observed in the Bottomside Ionospheric F-region Using the TIDDBIT HF Doppler Sounder

    NASA Astrophysics Data System (ADS)

    Crowley, G.

    2012-12-01

    HF Doppler sounders represent a low-cost and low-maintenance solution for monitoring wave activity in the F region ionosphere. HF Doppler sounders together with modern data analysis techniques can provide comprehensive traveling ionospheric disturbance (TID) characteristics, including both horizontal and vertical TID velocities and wavelengths across the entire spectrum from periods of 1 min to over an hour. Atmospheric and Space Technology Research Associates LLC has developed a new system called TIDDBIT (TID Detector Built in Texas), and data will be presented from a TIDDBIT system deployed in Virginia. Details of the analysis are provided by Crowley and Rodrigues [2012]. These results reinforce the relationship between atmospheric gravity waves (AGWs) and TIDs. The TID propagation azimuths rotate through 360 deg in 24 h, mimicking the rotation of the thermospheric winds but with approximately a 90 deg offset. The rotation of TID azimuths and thermospheric winds in Virginia is similar to that observed previously by other Northern Hemisphere systems [Crowley and McCrea, 1988] and opposite from the direction observed in Antarctica [Crowley et al., 1987]. These results illustrate the filtering effects that thermospheric neutral winds can have on the propagation of AGW. The completeness of the wave information obtained from the TIDDBIT system makes it possible to reconstruct the vertical displacement of isoionic contours over the 200 km horizontal dimension of the sounder array, and movies revealing the detailed shape and motion of isoionic surfaces will be shown. They resemble the surface of the ocean. Such information will be relevant for understanding the seeding of irregularities, as well as for several operational needs involving navigation, communication, and surveillance systems. Crowley, G. and I. W. McCrea (1988), A synoptic study of TIDs observed in the UK during the first WAGS campaign, October 10-18, 1985, Radio Sci., 23, 905-917. Crowley G., and F

  1. Assimilation of thermodynamic information from advanced infrared sounders under partially cloudy skies for regional NWP

    NASA Astrophysics Data System (ADS)

    Wang, Pei; Li, Jun; Goldberg, Mitchell D.; Schmit, Timothy J.; Lim, Agnes H. N.; Li, Zhenglong; Han, Hyojin; Li, Jinlong; Ackerman, Steve A.

    2015-06-01

    Generally, only clear-infrared spectral radiances (not affected by clouds) are assimilated in weather analysis systems. This is due to difficulties in modeling cloudy radiances as well as in observing their vertical structure from space. To take full advantage of the thermodynamic information in advanced infrared (IR) sounder observations requires assimilating radiances from cloud-contaminated regions. An optimal imager/sounder cloud-clearing technique has been developed by the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin-Madison. This technique can be used to retrieve clear column radiances through combining collocated multiband imager IR clear radiances and the sounder cloudy radiances; no background information is needed in this method. The imager/sounder cloud-clearing technique is similar to that of the microwave/IR cloud clearing in the derivation of the clear-sky equivalent radiances. However, it retains the original IR sounder resolution, which is critical for regional numerical weather prediction applications. In this study, we have investigated the assimilation of cloud-cleared IR sounder radiances using Atmospheric Infrared Sounder (AIRS)/Moderate Resolution Imaging Spectroradiometer for three hurricanes, Sandy (2012), Irene (2011), and Ike (2008). Results show that assimilating additional cloud-cleared AIRS radiances reduces the 48 and 72 h temperature forecast root-mean-square error by 0.1-0.3 K between 300 and 850 hPa. Substantial improvement in reducing track forecasts errors in the range of 10 km to 50 km was achieved.

  2. Role of the advanced IR sounder in land surface remote sensing

    NASA Astrophysics Data System (ADS)

    Knuteson, Robert O.

    2005-09-01

    A new era of Earth remote sensing began with the launch of the NASA EOS Aqua platform with the Atmospheric InfraRed Sounder (AIRS) in May 2002. The EOS AIRS instrument is the first in a series of high spectral resolution infrared spectrometers that will allow improved characterization of the global atmospheric temperature and water vapor structure. Follow-on operational sensors with similar sounding capability include the Cross-track InfraRed Sounder (CrIS) on the NPP/NPOESS satellites and the Infrared Advanced Sounding Interferometer (IASI) on the European METOP series. These so-called advanced infrared sounders will have a vital role to play in the remote sensing of land ecosystems. This paper describes how the use of Advanced IR Sounder data can be used to improve the accuracy of atmospheric corrections in the thermal IR and provide detailed information on the spectral dependence of the infrared land surface emissivity. Radiance observations from AIRS have been obtained over a large, uniform sandy desert region in the Libyan Desert suitable for evaluation of the 15-km footprints of the NASA AIRS advanced sounder. Analysis of this data indicates a spectral contrast of more than 30% between 12 mm and 9 mm in the surface infrared emissivity due to the presence of the mineral quartz with somewhat smaller contrast at 4 mm. Results of a method for separation of infrared surface emissivity and effective surface skin temperature are presented also.

  3. Advanced atmospheric sounder and imaging radiometer /AASIR/ for STORMSAT

    NASA Technical Reports Server (NTRS)

    Chase, S. C.

    1976-01-01

    The principal mission of the three-axis stabilized STORMSAT spacecraft is to provide the necessary meteorological data for tracking, studying the detailed structure, and modeling mesoscale weather phenomena. In the area of mesoscale events, the following meteorological objectives are indicated: high-quality imagery, visible and infrared; wind velocity from cloud tracers (1 m/sec), atmospheric temperature profiles (1 K), and atmospheric humidity sounding. These objectives are reflected in the functional characteristics of the AASIR, which is a second generation meteorological sensor based on the Visible Infrared Spin-Scan Radiometer (VISSR) and the Atmospheric Sounder (VAS). The AASIR design and interface constraints with the STORMSAT spacecraft is discussed.

  4. HIRS-AMTS satellite sounding system test - Theoretical and empirical vertical resolving power. [High resolution Infrared Radiation Sounder - Advanced Moisture and Temperature Sounder

    NASA Technical Reports Server (NTRS)

    Thompson, O. E.

    1982-01-01

    The present investigation is concerned with the vertical resolving power of satellite-borne temperature sounding instruments. Information is presented on the capabilities of the High Resolution Infrared Radiation Sounder (HIRS) and a proposed sounding instrument called the Advanced Moisture and Temperature Sounder (AMTS). Two quite different methods for assessing the vertical resolving power of satellite sounders are discussed. The first is the theoretical method of Conrath (1972) which was patterned after the work of Backus and Gilbert (1968) The Backus-Gilbert-Conrath (BGC) approach includes a formalism for deriving a retrieval algorithm for optimizing the vertical resolving power. However, a retrieval algorithm constructed in the BGC optimal fashion is not necessarily optimal as far as actual temperature retrievals are concerned. Thus, an independent criterion for vertical resolving power is discussed. The criterion is based on actual retrievals of signal structure in the temperature field.

  5. Improvement of retrieved FORMOSAT-3/COSMIC electron densities validated by ionospheric sounder measurements at Jicamarca

    NASA Astrophysics Data System (ADS)

    Aragon-Angel, A.; Liou, Y.-A.; Lee, C.-C.; Reinisch, B. W.; HernáNdez-Pajares, M.; Juan, M.; Sanz, J.

    2011-10-01

    Inversion techniques applied to GPS-LEO radio occultation data allow the retrieval of accurate and worldwide-distributed refractivity profiles, which, in the case of the ionosphere, can be converted into electron densities providing information regarding the electron content distribution in this atmospheric region. In order to guarantee the accuracy of the electron density retrievals, two key points should be taken into account: the horizontal gradients of the electronic distribution and the topside electron content above the LEO orbit. The deployment in April 2006 of the satellite Constellation Observing System for Meteorology Ionosphere and Climate (FORMOSAT-3/COSMIC), carrying GPS receivers on board, provides valuable radio occultation data with global and almost uniform coverage overcoming the sparsity of data from previous LEO missions (for instance, GPS/MET, CHAMP, and SAC-C). This is also one of the main limitations of other sources providing direct observations, such as ionosondes. In this study, the improved Abel transform inversion is used to analyze derived ionospheric electron density profiles of the whole year 2007 in a scenario with very high electron density gradients: The neighboring area of Jicamarca (76.9°W, 12°S, dip latitude: 1°N), Perú, located at very low latitude and close to the geomagnetic equator, and the influence of the Appleton-Hartree equatorial anomaly (Davies, 1990). Moreover, different strategies to account for the topside electron content in the occultation data inversion are compared and discussed, taking advantage of the availability of FORMOSAT-3/COSMIC data sets and manually calibrated measurements from Jicamarca DPS. Statistical results show that for the current scenario the improvements are only about 10%, evidencing that the lack of colocation is one important source of error for the classical Abel inversion. Implications with respect to the plasmaspheric contribution have been derived from this data set analysis, in

  6. Limb sounders tracking topographic gravity wave activity from the stratosphere to the ionosphere around midlatitude Andes

    NASA Astrophysics Data System (ADS)

    Alexander, P.; Torre, A.; Schmidt, T.; Llamedo, P.; Hierro, R.

    2015-10-01

    Several studies have shown that the surroundings of the highest Andes mountains at midlatitudes in the Southern Hemisphere exhibit gravity waves (GWs) generated by diverse sources which may traverse the troposphere and then penetrate the upper layers if conditions are favorable. There is a specific latitude band where that mountain range is nearly perfectly aligned with the north-south direction, which favors the generation of wavefronts parallel to this orientation. This fact may allow an optimization of procedures to identify topographic GW in some of the observations. We analyze data per season to the east and west of these Andes latitudes to find possible significant differences in GW activity between both sectors. GW effects generated by topography and convection are expected essentially on the eastern side. We use satellite data from two different limb sounding methods: the Global Positioning System radio occultation (RO) technique and the Sounding of the Atmosphere using Broadband Emission Radiometry instrument, which are complementary with respect to the height intervals, in order to study the effects of GW from the stratosphere to the ionosphere. Activity becomes quantified by the GW average potential energy in the stratosphere and mesosphere and by the electron density variance content in the ionosphere. Consistent larger GW activity on the eastern sector is observed from the stratosphere to the ionosphere (night values). However, this fact remains statistically significant at the 90% significance level only during winter, when GWs generated by topography dominate the eastern sector. On the contrary, it is usually assumed that orographic GWs have nearly zero horizontal phase speed and will therefore probably be filtered at some height in the neutral atmosphere. However, this scheme relies on the assumption that the wind is uniform and constant. Our results also suggest that it is advisable to separate night and day cases to study GWs in the ionosphere, as

  7. Ionospheric Doppler sounder as remote sensing for detection and prediction of severe storms

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Phan, T.; Smith, R. E.

    1978-01-01

    Atmospheric acoustic-gravity waves associated with severe storms are detected by a ground-based ionospheric sounding array, and the location of the severe storms responsible for the wave generation is determined by group ray path computation. Computations based on six events during the extreme tornado outbreak of April 3, 1974, and five single tornado events show that the wave sources are located near the location where tornadoes touchdown more than one hour later. In the hurricane case, the results indicate that waves were generated along the storm track more than 3 hours ahead of the actual location of the storm. The possibility of the development of the present system as a remote sensor for the detection and prediction of severe storms is discussed.

  8. A New Inversion Routine to Produce Vertical Electron-Density Profiles from Ionospheric Topside-Sounder Data

    NASA Technical Reports Server (NTRS)

    Wang, Yongli; Benson, Robert F.

    2011-01-01

    Two software applications have been produced specifically for the analysis of some million digital topside ionograms produced by a recent analog-to-digital conversion effort of selected analog telemetry tapes from the Alouette-2, ISIS-1 and ISIS-2 satellites. One, TOPIST (TOPside Ionogram Scalar with True-height algorithm) from the University of Massachusetts Lowell, is designed for the automatic identification of the topside-ionogram ionospheric-reflection traces and their inversion into vertical electron-density profiles Ne(h). TOPIST also has the capability of manual intervention. The other application, from the Goddard Space Flight Center based on the FORTRAN code of John E. Jackson from the 1960s, is designed as an IDL-based interactive program for the scaling of selected digital topside-sounder ionograms. The Jackson code has also been modified, with some effort, so as to run on modern computers. This modification was motivated by the need to scale selected ionograms from the millions of Alouette/ISIS topside-sounder ionograms that only exist on 35-mm film. During this modification, it became evident that it would be more efficient to design a new code, based on the capabilities of present-day computers, than to continue to modify the old code. Such a new code has been produced and here we will describe its capabilities and compare Ne(h) profiles produced from it with those produced by the Jackson code. The concept of the new code is to assume an initial Ne(h) and derive a final Ne(h) through an iteration process that makes the resulting apparent-height profile fir the scaled values within a certain error range. The new code can be used on the X-, O-, and Z-mode traces. It does not assume any predefined profile shape between two contiguous points, like the exponential rule used in Jackson s program. Instead, Monotone Piecewise Cubic Interpolation is applied in the global profile to keep the monotone nature of the profile, which also ensures better smoothness

  9. The Advanced Technology Microwave Sounder (ATMS): The First 10 Months On-Orbit

    NASA Technical Reports Server (NTRS)

    Kim, Edward; Lyu, C-H Joseph; Blackwell, Willaim; Leslie, R. Vince; Baker, Neal; Mo, Tsan; Sun, Ninghai; Bi, Li; Anderson, Kent; Landrum, Mike; DeAmici, Giovanni; Gu, Degui; Foo, Alex; Ibrahim, Wael; Robinson, Kris; Chidester, Lynn; Shiue, James

    2012-01-01

    The Advanced Technology Microwave Sounder (ATMS) is a new satellite microwave sounding sensor designed to provide operational weather agencies with atmospheric temperature and moisture profile information for global weather forecasting and climate applications. A TMS will continue the microwave sounding capabilities first provided by its predecessors, the Microwave Sounding Unit (MSU) and Advanced Microwave Sounding Unit (AMSU). The first ATMS was launched October 28, 2011 on board the NPOESS Preparatory Project (NPP) satellite. Microwave soundings by themselves are the highest-impact input data used by Numerical Weather Prediction (NWP) models, especially under cloudy sky conditions. ATMS has 22 channels spanning 23-183 GHz, closely following the channel set of the MSU, AMSU-A1/2, AMSU-B, Microwave Humidity Sounder (MHS), and Humidity Sounder for Brazil (HSB). All this is accomplished with approximately 1/4 the volume, 1/2 the mass, and 1/2 the power of the three AMSUs. A description of ATMS cal/val activities will be presented followed by examples of its performance after its first 10 months on orbit.

  10. Development of the Advanced Technology Microwave Sounder (ATMS) for NPOESS C1

    NASA Astrophysics Data System (ADS)

    Brann, C.; Kunkee, D.

    2008-12-01

    The National Polar-orbiting Operational Environmental Satellite System's Advanced Technology Microwave Sounder (ATMS) is planned for flight on the first NPOESS mission (C1) in 2013. The C1 ATMS will be the second instrument of the ATMS series and will provide along with the companion Cross-track Infrared Sounder (CrIS), atmospheric temperature and moisture profiles for NPOESS. The first flight of the ATMS is scheduled in 2010 on the NPOESS Preparatory Project (NPP) satellite, which is an early instrument risk reduction component of the NPOESS mission. This poster will focus on the development of the ATMS for C1 including aspects of the sensor calibration, antenna beam and RF characteristics and scanning. New design aspects of the C1 ATMS, required primarily by parts obsolescence, will also be addressed in this poster.

  11. The Advanced Technology Microwave Sounder (ATMS): First Year On-Orbit

    NASA Astrophysics Data System (ADS)

    Kim, E. J.; Lyu, C.; Blackwell, W. J.; Leslie, V.; Baker, N.; Mo, T.; Sun, N.; Bi, L.; Anderson, K.; Landrum, M.; De Amici, G.; Gu, D.; Foo, A.; Ibrahim, W.; Robinson, K.

    2012-12-01

    The Advanced Technology Microwave Sounder (ATMS) is a new satellite microwave sounding sensor designed to provide operational weather agencies with atmospheric temperature and moisture profile information for global weather forecasting and climate applications. ATMS will continue the microwave sounding capabilities first provided by its predecessors, the Microwave Sounding Unit (MSU) and Advanced Microwave Sounding Unit (AMSU). The first ATMS was launched October 28, 2011 on board the Suomi-NPOESS Preparatory Project (S-NPP) satellite and has just finished its first year on orbit. Microwave soundings by themselves are the highest-impact input data used by Numerical Weather Prediction (NWP) models; and ATMS, when combined with the Cross-track Infrared Sounder (CrIS), forms the Cross-track Infrared and Microwave Sounding Suite (CrIMSS). The microwave soundings help meet NWP sounding requirements under cloudy sky conditions and provide key profile information near the surface. Designed & built by Aerojet Corporation in Azusa, California, (now Northrop Grumman Electronic Systems), ATMS has 22 channels spanning 23—183 GHz, closely following the channel set of the MSU, AMSU-A1 and A2, AMSU-B, Microwave Humidity Sounder (MHS), and Humidity Sounder for Brazil (HSB). It continues their cross-track scanning geometry, but for the first time, provides Nyquist sample spacing. All this is accomplished with approximately one quarter the volume, one half the mass, and one half the power of the three AMSUs. A summary description of the ATMS design will be presented. Post-launch calibration/validation activities include geolocation determination, radiometric calibration using the on-board warm targets and cold space views, simultaneous observations by microwave sounders on other satellites, comparison vs. pre-launch thermovacuum test performance; observations vs. atmospheric model predicted radiances, and comparisons of soundings vs. radiosondes. Brief descriptions of these

  12. Vensis: Venus Advanced Radar For Subsurface And Ionosphere Sounding

    NASA Astrophysics Data System (ADS)

    Biccari, D.; Gurnett, D.; Jordan, R.; Huff, R.; Marinangeli, L.; Nielsen, E.; Ori, G. G.; Picardi, G.; Plaut, J.; Provvedi, F.; Seu, R.; Zampolini, E.

    Due to optically opaque atmosphere of Venus radar is the best way to observe the surface of the planet from orbit. Magellan has obtained global SAR imaging, as well as altimetry and emissivity. As a subsurface sounder, working at low frequency and preferably in the night time, VENSIS would obtain fundamentally different kinds of geologic information than Magellan, mapping of interfaces of geologic units (e.g. tessera, plains, lava flows, impact debris) could in fact be extended into the third di- mension. A subsurface investigation of the first 1-2 Km will show the internal defor- mations of the Venusian surface and will depict the structural styles of old crust which are essential to define the crust dynamics, an improved understanding of the evolu- tion of complex Venusian features is a key to define the geological evolution of the planet. Furthermore in standard subsurface sounding mode VENSIS will be able to transmit four different bandwidth, so the possibility of multi frequency observations will allow the estimate of the material attenuation in the crust and will give significant indications on the dielectric properties of the detected interfaces. Thus the Primary Scientific Objectives of VENSIS are the following: 1-Characterize surface roughness, composition and electrical properties at long wavelengths (orders of magnitude longer than Magellan) 2-Probe the subsurface of Venus (to few km depth) to detect and map geologic materials and large scale structures at planetary level VENSIS sounder, using active sounding in a frequency range of 100 kHz to 7 MHz, would also allow detailed characterization of the Venus ionosphere while in passive mode it can be used to detect lightning, the presence of which remains both controversial and critical to understand the behavior of the atmosphere and the possibility of present day volcanism. Therefore a secondary objective is to Probe the ionosphere to characterize interactions between the solar wind and the Venusian

  13. 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.

  14. The Advanced Technology Microwave Sounder (ATMS): First Year On-Orbit

    NASA Technical Reports Server (NTRS)

    Kim, Edward J.

    2012-01-01

    The Advanced Technology Microwave Sounder (ATMS) is a new satellite microwave sounding sensor designed to provide operational weather agencies with atmospheric temperature and moisture profile information for global weather forecasting and climate applications. A TMS will continue the microwave sounding capabilities first provided by its predecessors, the Microwave Sounding Unit (MSU) and Advanced Microwave Sounding Unit (AMSU). The first flight unit was launched a year ago in October, 2011 aboard the Suomi-National Polar-Orbiting Partnership (S-NPP) satellite, part of the new Joint Polar-Orbiting Satellite System (JPSS). Microwave soundings by themselves are the highest-impact input data used by Numerical Weather Prediction models; and A TMS, when combined with the Cross-track Infrared Sounder (CrIS), forms the Cross-track Infrared and Microwave Sounding Suite (CrIMSS). The microwave soundings help meet sounding requirements under cloudy sky conditions and provide key profile information near the surface. ATMS was designed & built by Aerojet Corporation in Azusa, California, (now Northrop Grumman Electronic Systems). It has 22 channels spanning 23-183 GHz, closely following the channel set of the MSU, AMSU-AI/2, AMSU-B, Microwave Humidity Sounder (MHS), and Humidity Sounder for Brazil (HSB). It continues their cross-track scanning geometry, but for the first time, provides Nyquist sample spacing. All this is accomplished with approximately V. the volume, Y, the mass, and Y, the power of the three AMSUs. A description will be given of its performance from its first year of operation as determined by post-launch calibration activities. These activities include radiometric calibration using the on-board warm targets and cold space views, and geolocation determination. Example imagery and zooms of specific weather events will be shown. The second ATMS flight model is currently under construction and planned for launch on the "Jl" satellite of the JPSS program in

  15. COSMIC-2: A Platform for Advanced Ionospheric Observations

    NASA Astrophysics Data System (ADS)

    Straus, P. R.; Betz, D. A.

    2013-12-01

    The equatorial component of the COSMIC-2 program will consist of 6 satellites to be flown in a 24 degree inclination/520 km altitude orbit. In addition to the primary GNSS radio occultation (RO) payload, to be provided by JPL, the USAF plans to fly a pair of space weather sensors: a multi-frequency radio beacon and the Velocity, Ion Density and Irregularities (VIDI) in-situ plasma sensor package. Together, these three instruments will provide data to address key issues related to the specification and forecast of ionospheric densities and the instabilities/irregularities associated with ionospheric scintillation. The TriG GNSS receiver will provide a substantial increase in the number of daily ionospheric observations relative to COSMIC-1, both in the RO limb-viewing and overhead geometries. These data will provide a significant improvement of assimilative model capabilities for providing accurate ionospheric specifications in the important equatorial region. In addition, TriG will make routine measurements of ionospheric scintillation at L-band frequencies, as pioneered by the CORISS instrument on C/NOFS. The radio beacon, together with a network of ground receivers, will enable direct measurement of scintillation effects on trans-ionospheric signal propagation across the UHF to S-band frequency spectrum. The VIDI sensors will measure the in-situ density depletions associated with scintillation-producing irregularities. Together, the beacon, TriG, and VIDI will provide an unprecedented ability to map equatorial ionospheric instabilities and their effects. The in-situ package will also provide observations of plasma drifts from which electric fields, the most important physical driver for equatorial ionospheric structure, can be inferred. This will enable advancements in ionospheric models to further improve specifications and forecasts. In addition to discussing ionospheric science and operational support aspects of the COSMIC-2 mission, this presentation will

  16. The Advanced Technology Microwave Sounder (ATMS): A New Operational Sensor Series

    NASA Technical Reports Server (NTRS)

    Kim, Edward; Lyu, Cheng-H Joseph; Leslie, R. Vince; Baker, Neal; Mo, Tsan; Sun, Ninghai; Bi, Li; Anderson, Mike; Landrum, Mike; DeAmici, Giovanni; Gu, Degui; Foo, Alex; Ibrahim, Wael; Robinson, Kris; Chidester, Lynn; Shiue, James

    2012-01-01

    ATMS is a new satellite microwave sounding sensor designed to provide operational weather agencies with atmospheric temperature and moisture profile information for global weather forecasting and climate applications. ATMS will continue the microwave sounding capabilities first provided by its predecessors, the Microwave Sounding Unit (MSU) and Advanced Microwave Sounding Unit (AMSU). The first ATMS was launched October 28, 2011 on board the Suomi National Polar-orbiting Partnership (S-NPP) satellite. Microwave soundings by themselves are the highest-impact input data used by Numerical Weather Prediction (NWP) models; and ATMS, when combined with the Cross-track Infrared Sounder (CrIS), forms the Cross-track Infrared and Microwave Sounding Suite (CrIMSS). The microwave soundings help meet NWP sounding requirements under cloudy sky conditions and provide key profile information near the surface

  17. Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) after nine years of operation: A summary

    NASA Astrophysics Data System (ADS)

    Orosei, R.; Jordan, R. L.; Morgan, D. D.; Cartacci, M.; Cicchetti, A.; Duru, F.; Gurnett, D. A.; Heggy, E.; Kirchner, D. L.; Noschese, R.; Kofman, W.; Masdea, A.; Plaut, J. J.; Seu, R.; Watters, T. R.; Picardi, G.

    2015-07-01

    Mars Express, the first European interplanetary mission, carries the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) to search for ice and water in the Martian subsurface. Developed by an Italian-US team, MARSIS transmits low-frequency, wide-band radio pulses penetrating below the surface and reflected by dielectric discontinuities linked to structural or compositional changes. MARSIS is also a topside ionosphere sounder, transmitting a burst of short, narrow-band pulses at different frequencies that are reflected by plasma with varying densities at different altitudes. The radar operates since July 2005, after the successful deployment of its 40 m antenna, acquiring data at altitudes lower than 1200 km. Subsurface sounding (SS) data are processed on board by stacking together a batch of echoes acquired at the same frequency. On ground, SS data are further processed by correlating the received echo with the transmitted waveform and compensating de-focusing caused by the dispersive ionosphere. Ground processing of active ionospheric sounding (AIS) data consists in the reconstruction of the electron density profile as a function of altitude. MARSIS observed the internal structure of Planum Boreum outlining the Basal Unit, an icy deposit lying beneath the North Polar Layered Deposits thought to have formed in an epoch in which climate was markedly different from the current one. The total volume of ice in polar layered deposits could be estimated, and parts of the Southern residual ice cap were revealed to consist of ≈ 10 m of CO2 ice. Radar properties of the Vastitas Borealis Formation point to the presence of large quantities of ice buried beneath the surface. Observations of the ionosphere revealed the complex interplay between plasma, crustal magnetic field and solar wind, contributing to space weather studies at Mars. The presence of three-dimensional plasma structures in the ionosphere was revealed for the first time. MARSIS could

  18. Calibration of Suomi national polar-orbiting partnership advanced technology microwave sounder

    NASA Astrophysics Data System (ADS)

    Weng, Fuzhong; Zou, Xiaolei; Sun, Ninghai; Yang, Hu; Tian, Miao; Blackwell, William J.; Wang, Xiang; Lin, Lin; Anderson, Kent

    2013-10-01

    The Suomi National Polar-Orbiting Partnership (NPP) satellite was launched on 28 October 2011 and carries the Advanced Technology Microwave Sounder (ATMS) on board. ATMS is a cross-track scanning instrument observing in 22 channels at frequencies ranging from 23 to 183 GHz, permitting the measurements of the atmospheric temperature and moisture under most weather conditions. In this study, the ATMS radiometric calibration algorithm used in the operational system is first evaluated through independent analyses of prelaunch thermal vacuum data. It is found that the ATMS peak nonlinearity for all the channels is less than 0.5 K, which is well within the specification. For the characterization of the ATMS instrument sensitivity or noise equivalent differential temperatures (NEDT), both standard deviation and Allan variance of warm counts are computed and compared. It is shown that NEDT derived from the standard deviation is about three to five times larger than that from the Allan variance. The difference results from a nonstationary component in the standard deviation of warm counts. The Allan variance is better suited than the standard deviation for describing NEDT. In the ATMS sensor brightness temperature data record (SDR) processing algorithm, the antenna gain efficiencies of main beam, cross-polarization beam, and side lobes must be derived accurately from the antenna gain distribution function. However, uncertainties remain in computing the efficiencies at ATMS high frequencies. Thus, ATMS antenna brightness temperature data records (TDR) at channels 1 to 15 are converted to SDR with the actual beam efficiencies whereas those for channels 16 to 22 are only corrected for the near-field sidelobe contributions. The biases of ATMS SDR measurements to the simulations are consistent between GPS RO and NWP data and are generally less than 0.5 K for those temperature-sounding channels where both the forward model and input atmospheric profiles are reliable.

  19. Characterization of geolocation accuracy of Suomi NPP Advanced Technology Microwave Sounder measurements

    NASA Astrophysics Data System (ADS)

    Han, Yang; Weng, Fuzhong; Zou, Xiaolei; Yang, Hu; Scott, Deron

    2016-05-01

    The Advanced Technology Microwave Sounder (ATMS) onboard Suomi National Polar-orbiting Partnership satellite has 22 channels at frequencies ranging from 23 to 183 GHz for probing the atmospheric temperature and moisture under all weather conditions. As part of the ATMS calibration and validation activities, the geolocation accuracy of ATMS data must be well characterized and documented. In this study, the coastline crossing method (CCM) and the land-sea fraction method (LFM) are utilized to characterize and quantify the ATMS geolocation accuracy. The CCM is based on the inflection points of the ATMS window channel measurements across the coastlines, whereas the LFM collocates the ATMS window channel data with high-resolution land-sea mask data sets. Since the ATMS measurements provide five pairs of latitude and longitude data for K, Ka, V, W, and G bands, respectively, the window channels 1, 2, 3, 16, and 17 from each of these five bands are chosen for assessing the overall geolocation accuracy. ATMS geolocation errors estimated from both methods are generally consistent from 40 cases in June 2014. The ATMS along-track (cross-track) errors at nadir are within ±4.2 km (±1.2 km) for K/Ka, ±2.6 km (±2.7 km) for V bands, and ±1.2 km (±0.6 km) at W and G bands, respectively. At the W band, the geolocation errors derived from both algorithms are probably less reliable due to a reduced contrast of brightness temperatures in coastal areas. These estimated ATMS along-track and cross-track geolocation errors are well within the uncertainty requirements for all bands.

  20. Biases in Total Precipitable Water Vapor Climatologies from Atmospheric Infrared Sounder and Advanced Microwave Scanning Radiometer

    NASA Technical Reports Server (NTRS)

    Fetzer, Eric J.; Lambrigtsen, Bjorn H.; Eldering, Annmarie; Aumann, Hartmut H.; Chahine, Moustafa T.

    2006-01-01

    We examine differences in total precipitable water vapor (PWV) from the Atmospheric Infrared Sounder (AIRS) and the Advanced Microwave Scanning Radiometer (AMSR-E) experiments sharing the Aqua spacecraft platform. Both systems provide estimates of PWV over water surfaces. We compare AIRS and AMSR-E PWV to constrain AIRS retrieval uncertainties as functions of AIRS retrieved infrared cloud fraction. PWV differences between the two instruments vary only weakly with infrared cloud fraction up to about 70%. Maps of AIRS-AMSR-E PWV differences vary with location and season. Observational biases, when both instruments observe identical scenes, are generally less than 5%. Exceptions are in cold air outbreaks where AIRS is biased moist by 10-20% or 10-60% (depending on retrieval processing) and at high latitudes in winter where AIRS is dry by 5-10%. Sampling biases, from different sampling characteristics of AIRS and AMSR-E, vary in sign and magnitude. AIRS sampling is dry by up to 30% in most high-latitude regions but moist by 5-15% in subtropical stratus cloud belts. Over the northwest Pacific, AIRS samples conditions more moist than AMSR-E by a much as 60%. We hypothesize that both wet and dry sampling biases are due to the effects of clouds on the AIRS retrieval methodology. The sign and magnitude of these biases depend upon the types of cloud present and on the relationship between clouds and PWV. These results for PWV imply that climatologies of height-resolved water vapor from AIRS must take into consideration local meteorological processes affecting AIRS sampling.

  1. Impact of advanced technology microwave sounder data in the NCMRWF 4D-VAR data assimilation system

    NASA Astrophysics Data System (ADS)

    Rani, S. Indira; Srinivas, D.; Mallick, Swapan; George, John P.

    2016-05-01

    This study demonstrates the added benefits of assimilating the Advanced Technology Microwave Sounder (ATMS) radiances from the Suomi-NPP satellite in the NCMRWF Unified Model (NCUM). ATMS is a cross-track scanning microwave radiometer inherited the legacy of two very successful instrument namely, Advanced Microwave Sounding Unit-A (AMSU-A) and Microwave Humidity Sounder (MHS). ATMS has 22 channels: 11 temperature sounding channels around 50-60 GHz oxygen band and 6 moisture sounding channels around the 183GHz water vapour band in addition to 5 channels sensitive to the surface in clear conditions, or to water vapour, rain, and cloud when conditions are not clear (at 23, 31, 50, 51 and 89 GHz). Before operational assimilation of any new observation by NWP centres it is standard practice to assess data quality with respect to NWP model background (short-forecast) fields. Quality of all channels is estimated against the model background and the biases are computed and compared against that from the similar observations. The impact of the ATMS data on global analyses and forecasts is tested by adding the ATMS data in the NCUM Observation Processing system (OPS) and 4D-Var variational assimilation (VAR) system. This paper also discusses the pre-operational numerical experiments conducted to assess the impact of ATMS radiances in the NCUM assimilation system. It is noted that the performance of ATMS is stable and it contributes to the performance of the model, complimenting observations from other instruments.

  2. Requirements for an Advanced Low Earth Orbit (LEO) Sounder (ALS) for improved regional weather prediction and monitoring of greenhouse gases

    NASA Astrophysics Data System (ADS)

    Pagano, Thomas S.; Chahine, Moustafa T.; Susskind, Joel

    2008-12-01

    Hyperspectral infrared atmospheric sounders (e.g. the Atmospheric Infrared Sounder (AIRS) on Aqua and the Infrared Atmospheric Sounding Interferometer (IASI) on MetOp) provide highly accurate temperature and water vapor profiles in the lower to upper troposphere. These systems are vital operational components of our National Weather Prediction system and the AIRS has demonstrated over 6 hrs of forecast improvement on the 5 day operational forecast1. Despite the success in the mid troposphere to lower stratosphere, a reduction in sensitivity and accuracy has been seen in these systems in the boundary layer over land. In this paper we demonstrate the potential improvement associated with higher spatial resolution (1km vs currently 13.5 km) on the accuracy of boundary layer products with an added consequence of higher yield of cloud free scenes. This latter feature is related to the number of samples that can be assimilated and has also shown to have a significant impact on improving forecast accuracy. We also present a set of frequencies and resolutions that will improve vertical resolution of temperature and water vapor and trace gas species throughout the atmosphere. Development of an Advanced Low Earth Orbit (LEO) Sounder (ALS) with these improvements will improve weather forecast at the regional scale and of tropical storms and hurricanes. Improvements are also expected in the accuracy of the water vapor and cloud properties products, enhancing process studies and providing a better match to the resolution of future climate models. The improvements of technology required for the ALS are consistent with the current state of technology as demonstrated in NASA Instrument Incubator Program and NOAA's Hyperspectral Environmental Suite (HES) formulation phase development programs.

  3. Requirements for an Advanced Low Earth Orbit (LEO) Sounder (ALS) for Improved Regional Weather Prediction and Monitoring of Greenhouse Gases

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Chahine, Moustafa T.; Susskind, Joel

    2008-01-01

    Hyperspectral infrared atmospheric sounders (e.g., the Atmospheric Infrared Sounder (AIRS) on Aqua and the Infrared Atmospheric Sounding Interferometer (IASI) on Met Op) provide highly accurate temperature and water vapor profiles in the lower to upper troposphere. These systems are vital operational components of our National Weather Prediction system and the AIRS has demonstrated over 6 hrs of forecast improvement on the 5 day operational forecast. Despite the success in the mid troposphere to lower stratosphere, a reduction in sensitivity and accuracy has been seen in these systems in the boundary layer over land. In this paper we demonstrate the potential improvement associated with higher spatial resolution (1 km vs currently 13.5 km) on the accuracy of boundary layer products with an added consequence of higher yield of cloud free scenes. This latter feature is related to the number of samples that can be assimilated and has also shown to have a significant impact on improving forecast accuracy. We also present a set of frequencies and resolutions that will improve vertical resolution of temperature and water vapor and trace gas species throughout the atmosphere. Development of an Advanced Low Earth Orbit (LEO) Sounder (ALS) with these improvements will improve weather forecast at the regional scale and of tropical storms and hurricanes. Improvements are also expected in the accuracy of the water vapor and cloud properties products, enhancing process studies and providing a better match to the resolution of future climate models. The improvements of technology required for the ALS are consistent with the current state of technology as demonstrated in NASA Instrument Incubator Program and NOAA's Hyperspectral Environmental Suite (HES) formulation phase development programs.

  4. Recent Advances in Mid-latitude Ionosphere/Thermosphere Science

    NASA Astrophysics Data System (ADS)

    Kelley, Michael

    One of the original reasons for building a National Ionospheric Observatory (now the National Astronomy and Ionospheric Center or NAIC) near Arecibo, Puerto Rico was the location, which is in the best behaved region of the ionosphere. At 30° magnetic latitude and 19° geographic latitude, it is well equatorward of the auroral and sub-auroral zones and poleward of the equatorial anomalies most of the time. The island thus has some of the best weather and space weather on the planet. However, similar to an occasional hurricane striking the island, the ionosphere overhead has occasional ionospheric and thermospheric disturbances. Some of these space weather phenomena, e.g., mesoscale TIDs and unstable sporadic E layers, are endemic to the region and, prior to the advent of airglow imagers and GPS networks, were difficult to visualize using radiowave data alone. Other weather events are caused by infringement on this zone from processes in more active weather regions. For example, neutral waves launched from the auroral oval (large scale TIDs) pass through the region; electric fields penetrate from the solar wind and create both plasma uplifts, causing positive ionospheric storms, and stormenhanced density plumes, coursing through the region. From the south, convective equatorial ionospheric storms create plasma bubbles that can reach mid-latitudes. Examples of data obtained during these phenomena, and possibly more, will be presented and discussed in light of our present understanding.

  5. 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

  6. New generation topside sounder

    NASA Astrophysics Data System (ADS)

    Ganguly, Suman; Wickwar, Vincent; Goodman, John M.

    2001-09-01

    Having ionospheric electron density distributions as a function of height, latitude, longitude, and time under different conditions is essential for scientific, technical, and operational purposes. A satellite-based, swept-frequency, HF sounder can obtain electron density profiles on a global scale. We are developing a new generation HF sounder that employs recent developments in technology, electronics, and processing capabilities. It will provide global-scale electron density distributions, contours of fixed densities, maps of ƒoF2, hmax, etc. It will allow us to map irregularities, estimate anomalous propagation and conditions for ducting, determine angles of arrival, etc. It will also be able to perform various plasma diagnostics and, because of new flexibility, will be programmable from the ground to perform a variety of experiments in space. Need for such a system exists through the Department of Defense and several civilian agencies. Some of the novel features of the system include software-based design, direction of arrival estimation and synthetic aperture radar-type operation, onboard processing, and reconfigurable and flexible architecture with multimission capabilities.

  7. Advanced solar irradiances applied to satellite and ionospheric operational systems

    NASA Astrophysics Data System (ADS)

    Tobiska, W. Kent; Schunk, Robert; Eccles, Vince; Bouwer, Dave

    Satellite and ionospheric operational systems require solar irradiances in a variety of time scales and spectral formats. We describe the development of a system using operational grade solar irradiances that are applied to empirical thermospheric density models and physics-based ionospheric models used by operational systems that require a space weather characterization. The SOLAR2000 (S2K) and SOLARFLARE (SFLR) models developed by Space Environment Technologies (SET) provide solar irradiances from the soft X-rays (XUV) through the Far Ultraviolet (FUV) spectrum. The irradiances are provided as integrated indices for the JB2006 empirical atmosphere density models and as line/band spectral irradiances for the physics-based Ionosphere Forecast Model (IFM) developed by the Space Environment Corporation (SEC). We describe the integration of these irradiances in historical, current epoch, and forecast modes through the Communication Alert and Prediction System (CAPS). CAPS provides real-time and forecast HF radio availability for global and regional users and global total electron content (TEC) conditions.

  8. Recent Advances and Difficulties of Infrasonic Wave Investigation in the Ionosphere

    NASA Astrophysics Data System (ADS)

    Krasnov, Valeriy M.; Drobzheva, Yana V.; Laštovička, Jan

    2006-03-01

    Acoustic waves have a remarkable ability to transfer energy from the ground up to the uppermost layers of the atmosphere. On the ground, there are many permanent sources of infrasound, and also pulsed and/or sporadic sources (e.g., sea waves, infrasonic and sonic noise of cities, lightning, earthquakes, explosions, etc.). The infrasonic waves carry away the major part of their energy upwards through the atmosphere. What are the consequences of the upward energy transfer? What heights of the atmosphere are supplied by energy from various sources of an infrasonic wave? In most cases, the answers to these questions are not well known at present. The only opportunity to monitor the propagation of an infrasonic wave to high altitudes is to watch for its influence on the ionospheric plasma. Unfortunately, most of standard equipment for ionospheric sounding, as a rule, cannot detect plasma fluctuations in the infrasonic range. Besides, the form of an infrasonic wave strongly varies during propagation due to nonlinear effects. However, the development of the Doppler method of radiosounding of the ionosphere has enabled progress to be made. Simultaneously, the ionospheric method for sensing aboveground and underground explosions has been developed. Its main advantage is the remote observation of an explosion in the near field zone by means of short radio waves, i.e., the radio sounding of the ionosphere directly above the explosion. The theory of propagation of an acoustic pulse produced by an explosion on the ground up to ionospheric heights has been developed better than the theory for other sources, and has been quantitatively confirmed by experiments. A review of some advances in the area of infrasound investigations at ionospheric heights is given and some current problems are presented.

  9. Recent advances in real-time analysis of ionograms and ionospheric drift measurements with digisondes

    NASA Astrophysics Data System (ADS)

    Reinisch, B. W.; Huang, X.; Galkin, I. A.; Paznukhov, V.; Kozlov, A.

    2005-08-01

    Reliable long distance RF communication and transionospheric radio links depend critically on space weather, and specifically ionospheric conditions. Modern ground-based ionosondes provide space weather parameters in real-time including the vertical electron density distribution up to ˜1000 km and the velocity components of the ionospheric F region drift. A global network of digisondes distributes this information in real-time via internet connections. The quality of the automatic scaling of the echo traces in ionograms was a continuous concern ever since first attempts have been reported. The modern low-power ionosonde with ˜100 W transmitters (compared to several kilowatt for the older ionosondes) relies on more sophisticated signal processing to enhance the signal-to-noise ratio and to retrieve the essential ionospheric characteristics. Recent advances in the automatic scaling algorithm ARTIST have significantly increased the reliability of the autoscaled data, making the data, in combination with models, more useful for ionospheric now-casting. Vertical and horizontal F region drift velocities are a new real-time output of the digisondes. The “ionosonde drift” is derived from the measured Doppler frequency shift and angle of arrival of ionospherically reflected HF echoes, a method similar to that used by coherent VHF and incoherent scatter radars.

  10. Lessons Learned from Previous Space-Borne Sounders as a Guide to Future Sounder Development

    NASA Technical Reports Server (NTRS)

    Benson, Robert F.; Deshpande, Manohar D.; Farrell,William M.; Fung, Shing F.; Osherovich, Vladimir A.; Pfaff, Rovert E.; Rowland, Douglas E.; Adrian, Mark L.

    2008-01-01

    Space-borne radio sounding is considered to be the gold standard for electron-density (N(sub e)) measurements compared to other techniques even under low-density conditions, such as N(sub e) < 1/cu cm, when other techniques are known to experience difficulties. These reliable measurements are not restricted to in-situ N(sub e) determinations since a spaceborne sounder can provide vertical N(sub e) profiles (N(sub e)(h)) from the spacecraft altitude to the altitude of maximum N(sub e). Near-conjunction studies involving the International Satellites for Ionospheric Studies (ISIS) satellites in the topside ionosphere and Dynamics Explorer 2 (DE 2) near the altitude of the F-region peak density have verified that, even at the greatest distance from the sounder, the ISIS-derived N(sub e)(h) profiles agree with the DE-2 Langmuir-probe measurements to within about 30% over a density range of more than two decades. Space-borne sounders can also provide N(sub e) profiles along the magnetic-field B, by inverting echoes that are ducted along field-aligned irregularities (FAI), and can provide information about the terrain beneath the satellite by examining surface reflections in the frequency range above the ionospheric penetration frequency. Many nations have launched rocket and satellite radio sounders in geospace over more than 4 decades and there have been sounders on space-probes and in orbit around other planets. Here we will summarize some of the lessons learned from these accomplishments by analyzing data from radio sounders on the Alouette and ISIS satellites and the OEDIPUS and other rockets in the terrestrial ionosphere, the IMAGE satellite in the terrestrial magnetosphere, the Ulysses space probe in Jupiter's 10 plasma torus and the MARSIS satellite in orbit around Mars. The emphasis will be on information deduced concerning (1) fundamental plasma processes and gradients in N, and B in the vicinity of the sounders from sounder-stimulated plasma resonances and

  11. Pre-Launch Characterization of the Advanced Technology Microwave Sounder (ATMS) on the Joint Polar Satellite System-1 Satellite (JPSS-1)

    NASA Astrophysics Data System (ADS)

    Kim, Edward; Leslie, Vince; Lyu, Joseph; Smith, Craig; McCormick, Lisa; Anderson, Kent

    2016-04-01

    The Advanced Technology Microwave Sounder (ATMS) is the newest generation of microwave sounder in the international fleet of polar-orbiting weather satellites, replacing the Advanced Microwave Sounding Unit (AMSU) which first entered service in 1998. The first ATMS was launched aboard the Suomi NPP (S-NPP) satellite in late 2011. The second ATMS is manifested on the Joint Polar Satellite System-1 Satellite (JPSS-1). ATMS provides 22 channels of temperature and humidity sounding observations over a frequency range from 23 to 183 GHz. These microwave soundings provide the highest impact data ingested by operational Numerical Weather Prediction (NWP) models, and are the most critical of the polar-orbiting satellite observations, particularly because microwave sensing can penetrate clouds. This paper will present performance characterizations from pre-launch calibration measurements of the JPSS-1 ATMS just completed in December, 2015. The measurements were conducted in a thermal vacuum chamber with blackbody targets simulating cold space, ambient, and a variable Earth scene. They represent the best opportunity for calibration characterization of the instrument since the environment can be carefully controlled. We will present characterizations of the sensitivity (NEDT), accuracy, nonlinearity, noise spectral characteristics, gain stability, repeatability, and inter-channel correlation. An estimate of expected "striping" will be presented, and a discussion of reflector emissivity effects will also be provided. Comparisons will be made with the S-NPP flight unit. Finally, we will describe planned on-orbit characterizations - such as pitch and roll maneuvers - that will further improve both the measurement quality and the understanding of various error contributions.

  12. Sounder updates for statistical model predictions of maximum usable frequencies on HF sky wave paths

    NASA Astrophysics Data System (ADS)

    Reilly, Michael H.; Daehler, Mark

    1986-12-01

    A method is presented for the short-term prediction of maximum usable frequencies (MUFs) in a large communications region. It is shown how ionospheric measurements from a network of ionospheric sounders can be used to update sunspot number or solar 10.7 cm flux inputs to a climatological MUF prediction model. MINIMUF in this case, which is then used to predict MUFs on paths throughout the region. Analysis of mid-latitude oblique-incidence sounder data sets indicates the advantage gained from single-path sounder updates of flux for MUF predictions on adjacent paths. Under specified conditions a further dramatic improvement in MUF prediction accuracy is found from spatial interpolation of sounder-updated flux values. MUF prediction accuracies within 0.5 MHz are obtained for fairly modest sounder network deployments, in which the sounder midpath point distributions and updating frequency satisfy particular requirements.

  13. Spaceborne Infrared Atmospheric Sounder

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas; Macenka, Steven; Kampe, Thomas

    2004-01-01

    A report describes the development of the spaceborne infrared atmospheric sounder (SIRAS) - a spectral imaging instrument, suitable for observing the atmosphere of the Earth from a spacecraft, that utilizes four spectrometers to cover the wavelength range of 12 to 15.4 m with a spectral resolution that ranges between 1 part per 900 and 1 part per 1,200 in wavelength. The spectrometers are operated in low orders to minimize filtering requirements. Focal planes receive the dispersed energy and provide a spectrum of the scene. The design of the SIRAS combines advanced, wide-field refractive optics with high-dispersion gratings in a solid-state (no moving parts), diffraction-limited optical system that is the smallest such system that can be constructed for the specified wavelength range and resolution. The primary structure of the SIRAS has dimensions of 10 by 10 by 14 cm and has a mass of only 2.03 kg

  14. A technique for recording HF (High Frequency) oblique-incidence-sounder data

    NASA Astrophysics Data System (ADS)

    Daehler, Mark

    1988-08-01

    This report details the equipment, formats, and procedures developed for recording and displaying HF propagation data produced by the AN/TRQ-35 RCS-4B oblique-incidence sounder receiver. The information is being published in this form because of numerous requests regarding a means for using the large volume of sounder data accumulated by NRL in the course of its ionospheric effects studies. These techniques may ultimately be incorporated in a proposed worldwide database of ionospheric data. The AN/TRQ-35 sounder equipment is available to all branches of the DOD and is widely used for near-real-time HF frequency management. The data it produces, if properly recorded and stored, can also be used for numerous other purposes related to studies of ionospheric structure and HF skywave communications. These include studies of the electron density versus height profile of the ionosphere; of forecasts of propagation conditions relevant to HF communications; of the geographical and temporal limitations of sounder data application; and of the effectiveness of frequency management techniques. Permanent records of ionospheric propagation have also proved valuable in evaluating tests of HF devices which are dependent on ionospheric propagation, such as communications transmitters and receivers, or direction finding equipment.

  15. The topside sounder database - Data screening and systematic biases

    NASA Astrophysics Data System (ADS)

    Verhulst, Tobias; Stankov, Stanimir M.

    2013-06-01

    The ionospheric topside sounder measurement database developed at the US National Space Science Data Center (NSSDC) is a valuable source of information when investigating the composition and complex dynamics of the upper ionosphere. The database is increasingly used by many scientists around the world for both research and development of empirical models. However, there is always a danger of indiscriminately using the data without properly assessing the data quality and applicability for a given purpose. This paper is concerned with the issue of data screening and pre-processing of the Alouette/ISIS topside sounder database. An overview of the original database availability and formatting is given and the use of solar and geomagnetic indices is discussed. Data screening procedures, concerning detection and handling of erroneous profiles, are also presented. Special attention is drawn to the systematic biases observed in the database and the possibilities for their removal.

  16. AIRS - the Atmospheric Infrared Sounder

    NASA Technical Reports Server (NTRS)

    Lambrigsten, Bjorn H.; Fetzer, Eric; Fishbein, Evan; Lee, Sung-Yung; Paganao, Thomas

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) was launched in 2002, along with two companion microwave sounders. This AIRS sounding suite is the most advanced atmospheric sounding system to date, with measurement accuracies far surpassing those of current weather satellites. From its sun synchronous polar orbit, the AIRS system provides more than 90% of the globe every 24 hours. Much of the post-launch period has been devoted to optimizing the 'retrieval' system used to derive atmospheric and other parameters from the observations and to validate those parameters. The geophysical parameters have been produced since the beginning of 2003 - the first data were released to the public in mid-2003, and future improved versions will be released periodically. The ongoing calibration/validation effort has confirmed that the system is very accurate and stable. There are a number of applications for the AIRS products, ranging from numerical weather prediction - where positive impact on forecast accuracy has already been demonstrated, to atmospheric research - where the AIRS water vapor products near the surface and in the mid and upper troposphere as well as in the stratosphere promise to make it possible to characterize and model phenomena that are key for short-term atmospheric processes, from weather patterns to long-term processes, such as interannual variability and climate change.

  17. Atmospheric Infrared Sounder on the Earth Observing System

    SciTech Connect

    Aumann, H.H.; Pagano, R.J. . Jet Propulsion Lab.)

    1994-03-01

    Recent breakthroughs in IR detector array and cryocooler technology have made it possible to convert the concepts of optimum, passive, IR sounding to a practical satellite-borne instrument: the Atmospheric infrared Sounder (AIRS), a grating array IR spectrometer temperature sounder. AIRS, together with the Advanced Microwave Sounding Unit and the Microwave Humidity Sounder, will form a complementary sounding system for the Earth Observing System to be launched in the year 2000. The three instruments are expected to become the new operational sounding system for the National Oceanic and Atmospheric Administration.

  18. Apollo lunar sounder experiment

    USGS Publications Warehouse

    Phillips, R.J.; Adams, G.F.; Brown, W.E., Jr.; Eggleton, R.E.; Jackson, P.; Jordan, R.; Linlor, W.I.; Peeples, W.J.; Porcello, L.J.; Ryu, J.; Schaber, G.; Sill, W.R.; Thompson, T.W.; Ward, S.H.; Zelenka, J.S.

    1973-01-01

    The scientific objectives of the Apollo lunar sounder experiment (ALSE) are (1) mapping of subsurface electrical conductivity structure to infer geological structure, (2) surface profiling to determine lunar topographic variations, (3) surface imaging, and (4) measuring galactic electromagnetic radiation in the lunar environment. The ALSE was a three-frequency, wide-band, coherent radar system operated from lunar orbit during the Apollo 17 mission.

  19. Internal structure of Planum Boreum, from Mars advanced radar for subsurface and ionospheric sounding data

    NASA Astrophysics Data System (ADS)

    Selvans, M. M.; Plaut, J. J.; Aharonson, O.; Safaeinili, A.

    2010-09-01

    An investigation of the internal structure of the ice-rich Planum Boreum (PB) deposit at the north pole of Mars is presented, using 178 orbits of Mars advanced radar for subsurface and ionospheric sounding data. For each radargram, bright, laterally extensive surface and subsurface reflectors are identified and the time delay between them is converted to unit thicknesses, using a real dielectric constant of 3. Results include maps of unit thickness, for PB and its two constituent units, the stratigraphically older basal unit (BU) and the stratigraphically younger north polar layered deposits (NPLD). Maps of the individual units' surface elevation are also provided. Estimates of water ice volume in each unit are (1.3 ± 0.2) × 106 km3 in PB, (7.8 ± 1.2) × 105 km3 in the NPLD, and (4.5 ± 1.0) × 105 km3 in the BU. No lithospheric deflection is apparent under PB, in agreement with previous findings for only the Gemina Lingula lobe, which suggests that a thick elastic lithosphere has existed at the north pole of Mars since before the emplacement of the BU. The extent of BU material in the Olympia Planum lobe of PB is directly detected, providing a more accurate map of BU extent than previously available from imagery and topography. A problematic area for mapping the BU extent and thickness is in the distal portion of the 290°E-300°E region, where MARSIS data show no subsurface reflectors, even though the BU is inferred to be present from other lines of evidence.

  20. Recent Advances in Studies of Ionospheric Modification Using Rocket Exhaust (Invited)

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.

    2009-12-01

    Rocket exhaust interacts with the ionosphere to produce a wide range of disturbances. A ten second burn of the Orbital Maneuver Subsystem (OMS) engines on the Space Shuttle deposits over 1 Giga Joule of energy into the upper atmosphere. The exhaust vapors travel at speeds between 4.7 and 10.7 km/s coupling momentum into the ions by both collisions and charge exchange. Long-lived plasma irregularities are formed by the artificial hypersonic “neutral wind” passing through the ionosphere. Charge exchange between the fast neutrals and the ambient ions yields high-speed ion beams that excite electro-static plasma waves. Ground based radar has been used to detect both field aligned irregularities and electrostatic turbulence driven by the Space Shuttle OMS exhaust. Molecular ions produced by the charge exchange with molecules in the rocket exhaust recombine with a time scale of 10 minutes leaving a residual plasma depression. This ionospheric “hole” fills in by ambipolar diffusion leaving a depleted magnetic flux tube. This large scale reduction in Pedersen conductivity can provide a seed for plasma interchange instabilities. For instance, a rocket firing on the bottom side of the ionosphere near the equator can trigger a Rayleigh-Taylor instability that is naturally seen as equatorial Spread-F. The Naval Research Laboratory has been exploring these phenomena with dedicated burns of the Space Shuttle OMS engines and exhaust releases from rockets. The Shuttle Ionospheric Modification with Pulsed Localized Exhaust (SIMPLEX) series of experiments uses ground radars to probe the ionosphere affected by dedicated burns of the Space Shuttle OMS engines. Radars located at Millstone Hill, Massachusetts; Arecibo, Puerto Rico; Jicamarca, Peru; Kwajalein, Marshall Island; and Alice Springs, Australia have participated in the SIMPLEX program. A companion program called Shuttle Exhaust Ionospheric Turbulence Experiment has or will use satellites to fly through the turbulence

  1. Topside sounder observations of equatorial bubbles

    NASA Technical Reports Server (NTRS)

    Dyson, P. L.; Benson, R. F.

    1978-01-01

    Large scale regions of depleted equatorial ionospheric plasma, called equatorial bubbles, are investigated using topside sounder data. The sounder's unique remote measuring capability enables the magnetic field-aligned nature of the bubbles to be investigated. A search of all available Alouette 2 and ISIS 1 ionograms during nighttime perigee passes near the magnetic equator has revealed a variety of echo signatures associated with bubbles. In addition to a sudden drop in electron density, these signatures usually include in situ spread F and ducted traces. The ducted traces have been used to determine the electron density distribution and to infer changes in ion composition along the magnetic field line within the duct associated with the bubble. In some cases it can be determined that the bubble is asymmetric with respect to the magnetic equator. Even though such features require 3 dimensional models for their explanation, the great field-aligned extent of the bubbles (relative to their cross section) suggests that current theories, which ignore variations along the magnetic field, are still applicable.

  2. 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.

  3. FMCW channel sounder with digital processing for measuring the coherence of wideband HF radio links

    NASA Astrophysics Data System (ADS)

    Salous, S.

    1986-08-01

    Multipath propagation, and in particular, the interference between the ordinary and the extraordinary waves, places a fundamental constraint on the performance of wideband HF skywave radio links. Furthermore, the dispersive nature of ionospheric propagation causes phase nonlinearity and hence distortion of narrow pulses. In this paper, an FMCW wideband sounder built for the purposes of characterizing the channel is described. Spectral analysis of the audio output of the sounder via the FFT algorithm is shown to permit measurement of thef amplitude/frequency function, the polarization bandwidth, the fade rate, the fade depth and the distortion of a narrow pulse, all for a desired isolated ionospheric propagation mode. The sounder was used to collect data over an oblique path in the UK. The results of applying the FFT processing technique to the experimental data are presented.

  4. Probing disturbances over canadian ionosphere using advance data analysis of wave decomposition

    NASA Astrophysics Data System (ADS)

    Kherani, Esfhan

    2016-07-01

    Using CHAIN network of GPS receivers, we present disturbances in total electron content (TEC) of the ionosphere on magnetically quiet day of 8 December 2009 and construct travel-time diagram to understand the propagation characteristics of these disturbances. We employ the wave decomposition method to identify the TEC disturbances. We found N-shaped amplified TEC disturbances at higher latitude around 80 N that appear during intensification of ionospheric current at ˜11 UT, suggesting them to be associated with energy input from magnetosphere. These TEC disturbances have spectral peak in between 55-65 minutes, originate in the vicnity of (80N,270W), propagate both southeastward and southwestward with similar velocity ˜80 m/s and arrives at latitude ˜55N around 20 UT. These propagation characteristcs classify them as medium-scale Traveling ionospheric disturbances (MSTIDs) and possibly of gravity wave origin. Noteworthy results of our study are following: (1) presence of dayside MSTIDs whose nightside counterpart is recently reported by Shiokawa et al (2012), (2) long-distance ˜2500 km propagation of dayside MSTIDs that is not reported for the nightside counterpart, (3) dayside MSIDs acquire largest amplitudes in 65-75 during 15-17 UT, similar to the nightside MSTIDs, (4) amplification of amplitudes of MSTIDs in the auroral oval latitudes and (5) identification of driving sources in two latitudes that enable them to propagate long distance.

  5. Recent advances in the vertical coupling in the Atmosphere-Ionosphere System

    NASA Astrophysics Data System (ADS)

    Knížová, Petra Koucká; Georgieva, Katya; Ward, William; Yiğit, Erdal

    2015-12-01

    Welcome to this special issue of the Journal of Atmospheric and Solar-Terrestrial Physics, dedicated to the investigation of the coupling phenomena in the neutral Atmosphere-Ionosphere System. This special issue covers processes in the Atmosphere-Ionosphere System that significantly influence and/or rule the coupling within the regions. Earth's atmospheric regions are intricately coupled to one another via various dynamical, chemical, and electrodynamic processes. The coupling effects can be seen on the modulation of the waves from the lower to upper atmosphere as well as from low- to high-latitudes, electrodynamic and compositional changes, and plasma irregularities at different latitudinal regions around the globe due to the varying energy inputs. A special attention is paid to the Mesosphere-Lower Thermosphere region that represents a critical region in various coupling processes between the lower/middle atmosphere and the upper atmosphere/ionosphere since it forms physical processes filter and shape the flux of waves ascending through the mesosphere into the overlying thermosphere. Varying energy inputs from the Sun and from the lower atmosphere is one of the topics. Processes contributing to the vertical coupling in the atmosphere are discussed on theoretical basis and with respect to recent and long-term experimental measurements as well. Solar activity represents an important factor that directly or indirectly modulates the coupling processes.

  6. Intensity of nightside MARSIS AIS surface reflections and implications for low-altitude ionospheric densities

    NASA Astrophysics Data System (ADS)

    Němec, F.; Morgan, D. D.; Diéval, C.; Gurnett, D. A.

    2015-04-01

    Spacecraft radar sounding signals at frequencies higher than the ionospheric peak plasma frequency are not reflected by the ionosphere. Instead, they make it to the ground where they are reflected by the planetary surface. We analyze the intensity of the surface reflections measured by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) ionospheric radar sounder on board the Mars Express spacecraft. Apart from the surface reflectivity and the spacecraft altitude, the detected intensity of surface reflections is controlled primarily by the signal attenuation during the ionospheric propagation. We focus on the nightside region, where the ionospheric densities in the main layer are too low to cause a significant attenuation and allow sampling of the surface reflections at frequencies down to 3 MHz. The attenuation occurs mainly at altitudes below 100 km, where the electron-neutral collision frequency is a maximum. The intensity of surface reflections can thus serve as a proxy for electron densities at low altitudes not accessible by the direct ionospheric radar sounding. We analyze the intensity of surface reflections as a function of relevant controlling parameters. The intensity of surface reflections is lower at higher solar zenith angles on the nightside and during the periods of larger solar activity. Moreover, it exhibits a seasonal variation that is related to the dust storm occurrence. The intensity of surface reflections is lower in areas of closed magnetic field lines, suggesting that nightside electron densities behave rather differently at low altitudes than at higher altitudes. This is confirmed by comparison with simultaneous observations of the main ionospheric layer.

  7. A Microwave Pressure Sounder

    NASA Technical Reports Server (NTRS)

    Flower, D. A.; Peckham, G. E.

    1978-01-01

    An instrument to measure atmospheric pressure at the earth's surface from an orbiting satellite would be a valuable addition to the expanding inventory of remote sensors. The subject of this report is such an instrument - the Microwave Pressure Sounder (MPS). It is shown that global-ocean coverage is attainable with sufficient accuracy, resolution and observational frequency for meteorological, oceanographic and climate research applications. Surface pressure can be deduced from a measurement of the absorption by an atmospheric column at a frequency in the wing of the oxygen band centered on 60 GHz. An active multifrequency instrument is needed to make this measurement with sufficient accuracy. The selection of optimum operating frequencies is based upon accepted models of surface reflection, oxygen, water vapor and cloud absorption. Numerical simulation using a range of real atmospheres defined by radiosonde observations were used to validate the frequency selection procedure. Analyses are presented of alternative system configurations that define the balance between accuracy and achievable resolution.

  8. Atmospheric infrared sounder on AIRS with emphasis on level 2 products

    NASA Technical Reports Server (NTRS)

    Lee, Sung-Yung; Fetzer, Eric; Granger, Stephanie; Hearty, Thomas; Lambrigtsen, Bjorn; Manning, Evan M.; Olsen, Edward; Pagano, Thomas

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) was launched aboard EOS Aqua in May of 2002. AIRS is a grating spectrometer with almost 2400 channels covering the 3.74 to 15.40 micron spectral region with a nominal spectral resolution ((nu)/(delta)(nu)) of 1200, with some gaps. In addition, AIRS has 4 channels in the NIR/VIS region. The AIRS operates in conjunction with the microwave sounders Advanced Microwave Sounding Unit (AMSU-A) and Humidity Sounder of Brazil (HSB). The microwave sounders are mainly used for cloud clearing of IR radiances, or to remove the effect of cloud on the IR radiances.

  9. Retrieval of atmospheric temperature and moisture vertical profiles from satellite Advanced Infrared Sounder radiances with a new regularization parameter selecting method

    NASA Astrophysics Data System (ADS)

    Zhang, Kun; Wu, Chunqiang; Li, Jun

    2016-06-01

    Considering the characteristics of nonlinear problems, a new method based on the L-curve method and including the concept of entropy was designed to select the regularization parameter in the one-dimensional variational analysis-based sounding retrieval method. In the first iteration, this method uses an empirical regularization parameter derived by minimizing the entropy of variables. During subsequent iterations, it uses the L-curve method to select the regularization parameter in the vicinity of the regularization parameter selected in the last iteration. The new method was employed to select the regularization parameter in retrieving atmospheric temperature and moisture profiles from Atmospheric Infrared Sounder radiance measurements selected from the first day of each month in 2008. The results show that compared with the original L-curve method, the new method yields 5.5% and 2.5% improvements on temperature and relative humidity profiles, respectively. Compared with the discrepancy principle method, the improvements on temperature and relative humidity profiles are 1.6% and 2.0%, respectively.

  10. Estimation of planetary surface roughness by HF sounder observation

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Ono, T.

    Japanese Martian exploration project "Nozomi" was to carry out several science missions. Plasma Wave Sounder, one of those onboard missions, was an HF sounder to study Martian plasma environment, and Martian surface with the altimetry mode (Oya and Ono, 1998) as well. The altimetry mode observation was studied by means of computer simulations utilizing the KiSS code which had been originally designed to simulate the SELENE Lunar Radar Sounder, a spaceborne HF GPR, based on Kirchhoff approximation theory (Kobayashi, Oya and Ono, 2002). We found an empirical power law for the standard deviation of observed altitudes over Gaussian random rough surfaces: it varies in proportion to the square of the RMS gradient of the surface √{2} hRMS{λ_0, where hRMS and λ_0 are the RMS height of the surface and the correlation distance of the surface, respectively. We applied Geometrical optics to understand this empirical power law, and derived a square power law for the standard deviation of the observed altitude. Our Geometrical optics model assumed the followings: 1) the observed surface is a Gaussian random rough surface, 2) the mean surface is a flat horizontal plane, 3) the observed surface echo is the back scattering echoes, 4) the observed altitude is the mean value of the apparent range of those back scattering echoes. These results imply that HF sounder may be utilized to measure the surface roughness of planetary bodies in terms of the RMS gradient of the surface. Refrence: H. Oya and T. Ono, A new altimeter for Mars land shape observations utilizing the ionospheric sounder system onboard the Planet-B spacecraft, Earth Planets Space, Vol. 50, pp.229-234, 1998 T. Kobayashi, H. Oya, and T. Ono, A-scope analysis of subsurface radar sounding of lunar mare region, Earth Planets Space, Vol. 54, pp.973-982, 2002

  11. Sounder-updated statistical model predictions of maximum usable frequency for HF sky wave predictions

    NASA Astrophysics Data System (ADS)

    Reilly, M. H.; Daehler, M.

    1985-10-01

    Measured solar parameters, such as sunspot number or 10.7 cm flux, have traditionally been used as inputs to drive statistical model predictions of maximum usable frequencies (MUFs) on HF radio sky wave paths of interest. Much greater accuracy can be obtained by using ionospheric sounder inputs to drive or update statistical model predictions, and this is demonstrated here using oblique-incidence sounder data from the DoD Solid Shield exercises on May 12-14, 1981. From analysis of ionograms collected for several paths every fifteen minutes, it is found that deployment of a reasonable number of sounders in a large area, in order to update the simple statistical model, MINIMUF, yields MUF prediction capability on unsounded communication paths in the area within 0.4 MHz rms error. This value is obtained from real-time updating and a spatial interpolation process developed here, whereby data at sounder control points is interpolated to ionospheric reflection points for communication paths of interest. The results from the interpolation are found to be at least 20-30% more accurate than updating at any one of the nearby sounder control points. The updating procedure applies under day and night conditions, and also works well in a forecasting mode (not real-time), where it is found to work better in this case than a statistical trend line approach for daytime forecasting.

  12. New Ionospheric Interaction Experiments

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.

    2004-11-01

    Current upgrades to both the HF transmitter and diagnostic capabilities at the HAARP facility near Gakona, AK will permit a new generation ionospheric interaction experiments. We explore some of the new phenomena accessible with significantly increased ERP. Large-scale long-lived density structures induced by the HF pump in the ionospheric plasma are investigated. Long-lived density structures which convect with the ambient ionosphere, may serve as tracers for ionospheric flows and fields. Recent advances in HF and VHF radar diagnostics available for HAARP experiments, permit plasma wave detection and monitoring. We survey the mode structures expected with the next generation of high intensity experiments. Together with existing complementary diagnostics such as stimulated HF emissions and optical effects, these data will provide unprecedented views of highly nonlinear phenomena induced by high intensity RF radiation in the ionosphere.

  13. Space Electron Density Gradient Studies using a 3D Embedded Reconfigurable Sounder and ESA/NASA CLUSTER Mission

    NASA Astrophysics Data System (ADS)

    Dekoulis, George

    2016-07-01

    This paper provides a direct comparison between data captured by a new embedded reconfigurable digital sounder, different ground-based ionospheric sounders spread around Europe and the ESA/NASA CLUSTER mission. The CLUSTER mission consists of four identical space probes flying in a formation that allows measurements of the electron density gradient in the local magnetic field. Both the ground-based and the spacecraft instrumentations assist in studying the motion, geometry and boundaries of the plasmasphere. The comparison results are in accordance to each other. Some slight deviations among the captured data were expected from the beginning of this investigation. These small discrepancies are reasonable and seriatim analyzed. The results of this research are significant, since the level of the plasma's ionization, which is related to the solar activity, dominates the propagation of electromagnetic waves through it. Similarly, unusually high solar activity presents serious hazards to orbiting satellites, spaceborne instrumentation, satellite communications and infrastructure located on the Earth's surface. Long-term collaborative study of the data is required to continue, in order to identify and determine the enhanced risk in advance. This would allow scientists to propose an immediate cure.

  14. The Evolution of Spaceborne Microwave Sounders for the U.S. Polar-Orbiting Weather Satellites

    NASA Technical Reports Server (NTRS)

    Shiue, James C.; Krimschansky, Sergey; Patel, Probodh; Hildebrand, Peter (Technical Monitor)

    2002-01-01

    The Advanced Technology Microwave Sounder (ATMS) is the next generation space-borne microwave sounder. It is the latest and most advanced version of a series of satellite-based microwave sounders, currently under development by NASA for the future U.S. operational polar-orbiting weather satellite system, called the NPOESS (National Polar-orbiting Operational Environment Satellite System), slated to begin orbiting around the end of this decade. This paper will present a brief history of the evolution of the space-borne microwave sounders, from its early-day scientific experiments, through the operational sounder aboard today's polar orbiting weather satellites, and ending in the ATMS development. It will also describe the evolution of microwave radiometer technology that enabled the space-borne microwave radiometry, from its early versions with simple, nadir-viewing, fixed-horn antennas to the present-day scanning reflector antennas with broad-band MMIC Low Noise Amplifiers, plus on-board calibrations.

  15. Atmospheric Infrared Sounder on the Earth Observing System

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.

    1995-01-01

    The Atmospheric Infrared Sounder (AIRS) is a high spectral resolution IR spectrometer. AIRS, together with the Advanced Microwave Sounding Unit (AMSU) and the Microwave Humidity Sounder (MHS), is designed to meet the operational weather prediction requirements of the National Oceanic and Atmospheric Administration (NOAA) and the global change research objectives of the National Aeronautics and Space Administration (NASA). The three instruments will be launched in the year 2000 on the EOS-PM spacecraft. Testing of the AIRS engineering model will start in 1996.

  16. Instrument technology for magnetosphere plasma imaging from high Earth orbit. Design of a radio plasma sounder. Final report

    SciTech Connect

    Haines, D.M.; Reinisch, B.W.

    1995-01-01

    The use of radio sounding techniques for the study of the ionospheric plasma dates back to G. Briet and M. A. Tuve in 1926. Ground based swept frequency sounders can monitor the electron number density (N{sub e}) as a function of height (the N{sub e} profile). These early instruments evolved into a global network that produced high-resolution displays of echo time delay vs frequency on 35-mm film. These instruments provided the foundation for the success of the International Geophysical Year. The Alouette and International Satellites for Ionospheric Studies (ISIS) programs pioneered the used of spaceborne, swept frequency sounders to obtain N{sub e} profiles of the topside of the ionosphere, from a position above the electron density maximum. Repeated measurements during the orbit produced an orbital plane contour which routinely provided density measurements to within 10%. The Alouette/ISIS experience also showed that even with a high powered transmitter (compared to the low power sounder possible today) a radio sounder can be compatible with other imaging instruments on the same satellite. Digital technology was used on later spacecraft developed by the Japanese (the EXOS C and D) and the Soviets (Intercosmos 19 and Cosmos 1809). However, a full coherent pulse compression and spectral integrating capability, such as exist today for ground-based sounders (Reinisch et al.), has never been put into space. NASA`s 1990 Space Physics Strategy Implementation Study `The NASA Space Physics Program from 1995 to 2010` suggested using radio sounders to study the plasmasphere and the magnetopause and its boundary layers (Green and Fung). Both the magnetopause and plasmasphere, as well as the cusp and boundary layers, can be observed by a radio sounder in a high-inclination polar orbit with an apogee greater than 6 R{sub e} (Reiff et al.; Calvert et al.).

  17. Space Plasma Slab Studies using a new 3D Embedded Reconfigurable MPSoC Sounder

    NASA Astrophysics Data System (ADS)

    Dekoulis, George

    2016-07-01

    This paper presents recent ionospheric slab thickness measurements using a new mobile digital sounder system. The datasets obtained have been compared to the results of existing sounders in operation. The data validity has been verified. The slab thickness data allow constant monitoring of the lower ionosphere revealing the dynamic trends of the physical processes being involved. The prototype offers a tremendous amount of hardware processing power and a previously unseen response time in servicing the input and output data interfaces. This has been enabled by incorporating the latest three-dimensional Ultrascale+ technologies available commercially from the reconfigurable Field Programmable Gate Array (FPGA) computing industry. Furthermore, a previously developed Network-on-Chip (NoC) design methodology has been incorporated for connecting and controlling the application driven multiprocessor network. The system determines electron distributions, aggregate electromagnetic field gradients and plasma current density.

  18. ULF wave occurrence statistics in a high-latitude HF Doppler sounder

    NASA Astrophysics Data System (ADS)

    Wright, D. M.; Yeoman, T. K.; Jones, T. B.

    1999-06-01

    Ultra low frequency (ULF) wave activity in the high-latitude ionosphere has been observed by a high frequency (HF) Doppler sounder located at Tromsø, Norway (69.7°N, 19.2°E geographic coordinates). A statistical study of the occurrence of these waves has been undertaken from data collected between 1979 and 1984. The diurnal, seasonal, solar cycle and geomagnetic activity variations in occurrence have been investigated. The findings demonstrate that the ability of the sounder to detect ULF wave signatures maximises at the equinoxes and that there is a peak in occurrence in the morning sector. The occurrence rate is fairly insensitive to changes associated with the solar cycle but increases with the level of geomagnetic activity. As a result, it has been possible to characterise the way in which prevailing ionospheric and magnetospheric conditions affect such observations of ULF waves.

  19. Long-distance HF propagation modes deduced from the simultaneous observation by chirp sounder and ISS-b

    NASA Astrophysics Data System (ADS)

    Ichinose, M.; Fujii, S.; Nozaki, K.; Igi, S.

    1982-06-01

    Chirp oblique sounding data and ionospheric data gathered by the ISS-b satellite were analyzed to characterize the propagation modes between West Germany and Japan. Hourly ionograms were generated from November 1978 to May 1979 using chirp sounder operating in the 4-30 MHz range, and ionospheric conditions were measured each time the ISS-b orbit crossed the circuit. Propagation times were quantified for each frequency step by entering the measured ionosphere parameters into a parabolic model for the F2 layer. Simulations were performed for 3- to 5-hop propagation modes and compared with empirical data, showing that the MOF exceeds a theoretical MUF by 1 MHz.

  20. TIDDBIT HF Doppler Sounder Measurements of TIDs During the Wallops Island Rocket Launch of October 2007

    NASA Astrophysics Data System (ADS)

    Reynolds, A.; Crowley, G.; Rodrigues, F.; Earle, G.; Bullett, T.; Bishop, R.

    2008-12-01

    The TID Detector Built In Texas (TIDDBIT) sounder was deployed on the East Coast near Wallops Island to support a rocket launch in October 2007. The purpose of the rocket experiment was to study mid-latitude spread-F (MSF), and TIDDBIT provided information on the TID characteristics during the launch and for several days surrounding the launch. The sounder data confirm that waves were present during the rocket launch. This presentation reviews the TIDDBIT results from the experiment, contrasting data collected on different days, and from the same dates a year earlier. HF Doppler sounders represent a low-cost and low- maintenance solution for monitoring acoustic and gravity wave activity in the F-region ionosphere. HF Doppler sounders together with modern data analysis techniques provide both horizontal and vertical phase trace velocities across the entire TID spectrum from periods of 30-s to several hours. ASTRA has extensive experience with HF systems, and is currently building TIDDBIT sounders in New Mexico, and Peru.

  1. Investigation of Radio Wave Propagation in the Martian Ionosphere Utilizing HF Sounding Techniques

    NASA Astrophysics Data System (ADS)

    Yowell, Robert J.

    1996-06-01

    This thesis presents a preliminary design of an ionospheric sounder to be carried aboard one or more of NASA's Mars Surveyor landers. Past Russian and American probes have indicated the existence of an ionosphere, but none of these missions remotely sensed this atmospheric layer from the surface. The rationale for utilizing a surface-based Martian ionospheric sounder is discussed. Based on NASA's choice of launch vehicle and power source, a low-weight, low-powered Chirp sounder using a horizontally-polarized dipole antenna is recommended for the sounder experiment. The sounder experiment should be conducted for at least one Martian year, in order to investigate significant changes in radio propagation during seasonal transitions. Specific data compression techniques are suggested in order to reduce the quantity of data transferred from each sounder. The Appendix presents an overview of Earth's ionospheric structure and solar cycle effects. Finally, a Matlab software model of a hypothetical ionogram as measured from the Martian surface is presented.

  2. Atmospheric Infrared Sounder (AIRS) Project Status

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.

    2006-01-01

    This viewgraph presentation reviews the status of the Atmospheric Infrared Sounder (AIRS) and the Advanced Microwave Sounding Unit (AMSU). These instruments are on board the EOS Aqua Spacecraft that was launched May 4, 2002. The instruments are working normally. The objectives of the mission were to improve weather forecasting, assist in climate studies, and provide information as to the composition of Earth's atmosphere. The Aqua spacecraft is operating normally, the the primary life-limiting resource is fuel for maneuvers. The presentation also contains charts indicating who are using the data. There is information on the type of data available, and the propsal process. Also there is a few views of some of the planned instruments that were made possible in part due to the success of AIRS.

  3. The multi-instrumental radio diagnostics of the ionosphere for Space Weather Program

    NASA Astrophysics Data System (ADS)

    Krankowski, Andrzej; Rothkaehl, Hanna; Pulinets, Sergey; Cherniak, Iurii; Zakharenkova, Irina

    2015-04-01

    To give a more detailed and complete understanding of physical plasma processes that govern the solar-terrestrial space, and to develop qualitative and quantitative models of the magnetosphere-ionosphere-thermosphere coupling, it is necessary to design and build the next generation of instruments for space diagnostics and monitoring. Novel ground- based wide-area sensor networks, such as the LOFAR (Low Frequency Array) radar facility, comprising wide band, and vector-sensing radio receivers and multi-spacecraft plasma diagnostics should help to solve outstanding problems of space physics and describe long-term environmental changes. The LOw Frequency ARray - LOFAR - is a new fully digital radio telescope designed for frequencies between 30 MHz and 240 MHz located in Europe. The three new LOFAR stations will be installed until summer 2015 in Poland. The LOFAR facilities in Poland will be distributed among three sites: Lazy (East of Krakow), Borowiec near Poznan and Baldy near Olsztyn. Each site will host one LOFAR station (96 high-band+96 low-band antennas). The new digital radio frequency analyzer (RFA) on board the low-orbiting RELEC satellite was designed to monitor and investigate the ionospheric plasma properties. In addition to the in-situ space plasma measurements the topside sounders will be installed onboard the "Ionosphere" spacecrafts to retrieve the vertical distribution of electron concentration in the topside ionosphere. The first two satellites are scheduled for launch at the first half of 2016. These two-point ground-based and topside ionosphere-located space plasma diagnostic can be a useful new tool for monitoring and diagnosing turbulent plasma properties. In order to improve and validate the large scale and small scale ionospheric structures we will also use the GPS observations collected at IGS/EPN: global and regional TEC maps created with high special and temporal resolution, ROTI maps over the Northern Hemisphere and the data retrieved from

  4. Instrument technology for magnetosphere plasma imaging from high Earth orbit. Design of a radio plasma sounder

    NASA Technical Reports Server (NTRS)

    Haines, D. Mark; Reinisch, Bodo W.

    1995-01-01

    The use of radio sounding techniques for the study of the ionospheric plasma dates back to G. Briet and M. A. Tuve in 1926. Ground based swept frequency sounders can monitor the electron number density (N(sub e)) as a function of height (the N(sub e) profile). These early instruments evolved into a global network that produced high-resolution displays of echo time delay vs frequency on 35-mm film. These instruments provided the foundation for the success of the International Geophysical Year (1958). The Alouette and International Satellites for Ionospheric Studies (ISIS) programs pioneered the used of spaceborne, swept frequency sounders to obtain N(sub e) profiles of the topside of the ionosphere, from a position above the electron density maximum. Repeated measurements during the orbit produced an orbital plane contour which routinely provided density measurements to within 10%. The Alouette/ISIS experience also showed that even with a high powered transmitter (compared to the low power sounder possible today) a radio sounder can be compatible with other imaging instruments on the same satellite. Digital technology was used on later spacecraft developed by the Japanese (the EXOS C and D) and the Soviets (Intercosmos 19 and Cosmos 1809). However, a full coherent pulse compression and spectral integrating capability, such as exist today for ground-based sounders (Reinisch et al., 1992), has never been put into space. NASA's 1990 Space Physics Strategy Implementation Study "The NASA Space Physics Program from 1995 to 2010" suggested using radio sounders to study the plasmasphere and the magnetopause and its boundary layers (Green and Fung, 1993). Both the magnetopause and plasmasphere, as well as the cusp and boundary layers, can be observed by a radio sounder in a high-inclination polar orbit with an apogee greater than 6 R(sub e) (Reiff et al., 1994; Calvert et al., 1995). Magnetospheric radio sounding from space will provide remote density measurements of

  5. Report from ionospheric science

    NASA Technical Reports Server (NTRS)

    Raitt, W. J.; Banks, Peter M.; Nagy, A. F.; Chappell, C. R.

    1989-01-01

    The general strategy to advance knowledge of the ionospheric component of the solar terrestrial system should consist of a three pronged attack on the problem. Ionospheric models should be refined by utilization of existing and new data bases. The data generated in the future should emphasize spatial and temporal gradients and their relation to other events in the solar terrestrial system. In parallel with the improvement in modeling, it will be necessary to initiate a program of advanced instrument development. In particular, emphasis should be placed on the area of improved imaging techniques. The third general activity to be supported should be active experiments related to a better understanding of the basic physics of interactions occurring in the ionospheric environment. These strategies are briefly discussed.

  6. Advanced Ion Mass Spectrometer for Giant Planet Ionospheres, Magnetospheres and Moons

    NASA Astrophysics Data System (ADS)

    Sittler, EC; Cooper, JF; Paschalidis, N.; Jones, SL; Rodriguez, M.; Ali, A.; Coplan, MA; Chornay, DJ; Sturner; Bateman, FB; Andre, N.; Fedorov, A.; Wurz, P.

    2015-10-01

    The Advanced Ion Composition Spectrometer (AIMS) has been under development from various NASA sources (NASA LWSID, NASA ASTID, NASA Goddard IRADs) to measure elemental, isotopic, and simple molecular composition abundances of 1 eV/e to 25 keV/e hot ions with wide field-of-view (FOV) in the 1 - 60 amu mass range at mass resolution M/ΔM ≤ 60 over a wide dynamic range of intensities and penetrating radiation background from the inner magnetospheres of Jupiter and Saturn to the outer magnetospheric boundary regions and the upstream solar wind. This instrument will work for both spinning spacecraft and 3-axis stabilized spacecraft with wide field-of-view capability in both cases. It will measure the ion velocity distribution functions (IVDF) for the individual ion species; ion velocity moments of the IVDF will give the fluid parameters (density, flow velocity and temperature) of the individual ion species. Outer planet mission applications are Io Observer, Jupiter Europa Orbiter/Europa Clipper, Enceladus Orbiter, and Uranus Orbiter as described in the decadal survey, but would also be valuable for inclusion on other missions to outer planet destinations such as Saturn- Titan and Neptune-Triton and for future missions to terrestrial planets, Venus and Mars, the Moon, asteroids, and comets, and of course for geospace applications to the Earth.

  7. Co-Investigator Participation in the Mars-94 Mission Studies of the Mars-Solar Wind Interaction: Topside Sounder and Magnetometer

    NASA Technical Reports Server (NTRS)

    Luhmann, Janet G. (Principal Investigator)

    1996-01-01

    The purpose of this investigation has been to provide United States co-investigator support toward the preparation of the Topside Ionospheric Sounder and Magnetometer experiments on the Russian Mars-96 (previously Mars-94) mission. The main role has been to assist in the preparation of software tools for the optimum design of the investigation and the evaluation of mission operational plans and orbits.

  8. Geostationary-satellite beacon-receiver array for studies of ionospheric irregularities

    SciTech Connect

    Carlos, R.C.; Jacobson, A.R.; Wu, Guanghui

    1992-09-01

    Ionospheric irregularities can be studied by various techniques. These include widely spaced Doppler sounders or ionosondes, Faraday rotation polarimetry, and two-frequency differential Doppler, and radio interferometry. With geostationary satellites, one usually uses Faraday rotation of the beacon signal to measure the ionospheric TEC. With a network of polarimeters, the horizontal wave parameters of Traveling Ionospheric Disturbances (TIDS) can be deduced, but the shortcoming of this technique is its poor sensitivity. This paper describes a geostationary-satellite beacon-receiver array at Los Alamos, New Mexico, which will be employed for the studying of ionospheric irregularities, especially the fine-scale TIDS.

  9. Geostationary-satellite beacon-receiver array for studies of ionospheric irregularities

    SciTech Connect

    Carlos, R.C.; Jacobson, A.R.; Wu, Guanghui.

    1992-01-01

    Ionospheric irregularities can be studied by various techniques. These include widely spaced Doppler sounders or ionosondes, Faraday rotation polarimetry, and two-frequency differential Doppler, and radio interferometry. With geostationary satellites, one usually uses Faraday rotation of the beacon signal to measure the ionospheric TEC. With a network of polarimeters, the horizontal wave parameters of Traveling Ionospheric Disturbances (TIDS) can be deduced, but the shortcoming of this technique is its poor sensitivity. This paper describes a geostationary-satellite beacon-receiver array at Los Alamos, New Mexico, which will be employed for the studying of ionospheric irregularities, especially the fine-scale TIDS.

  10. Ionosphere research

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A report is presented on on-going research projects in ionospheric studies. The topics discussed are planetary atmospheres, E and F region, D region, mass spectrometer measurements, direct measurements and atmospheric reactions.

  11. Ionospheric research

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Data from research on ionospheric D, E, and F, regions are reported. Wave propagation, mass spectrometer measurements, and atmospheric reactions of HO2 with NO and NO2 and NH2 with NO and O2 are summarized.

  12. PREMIER's imaging IR limb sounder

    NASA Astrophysics Data System (ADS)

    Kraft, Stefan; Caron, Jerome; Bézy, Jean-Loup; Meynart, Roland; Langen, Jörg; Carnicero Dominguez, Bernardo; Bensi, Paolo; Silvestrin, Pierluigi

    2011-11-01

    The Imaging IR Limb Sounder (IRLS) is one of the two instruments planned on board of the candidate Earth Explorer Core Mission PREMIER. PREMIER stands for PRocess Exploration through Measurements of Infrared and Millimetrewave Emitted Radiation and is presently under feasibility study by ESA. Emerging from recent enhanced detector and processing technologies IRLS shall, next to a millimetre-wave limb sounder, explore the benefits of three-dimensional limb sounding with embedded cloud imaging capability. Such 3d imaging technology is expected to open a new era of limb sounding that will allow detailed studies of the link between atmospheric composition and climate, since it will map simultaneously fields of temperature and many trace gases in the mid/upper troposphere and stratosphere across a large vertical and horizontal field of view and with relatively high vertical and horizontal resolution. PREMIER shall fly in tandem formation looking backwards to METOP's swath and thereby explore the benefit of 3-dimensional information for meteorological/environmental analyses and climate forcing investigations. As currently planned and if implemented, IRLS will cover a total horizontal field of about 360 km and observe the limb at altitudes between 4 and 52 km. The vertical spatial sampling distance (SSD) will be well below 1 km. It will be run in two different exclusive modes to address scientific questions about atmospheric dynamics and chemistry at spectral samplings of ~1.2 cm-1 and ~0.2 cm-1, respectively. In such configuration IRLS will be composed of an imaging array with about 1800 macro pixels or sub-samples, thereby allowing cloud imaging and rejection at sufficient spatial resolution. We will present an overview of the instrument requirements as derived from the scientific requirements, the present status of the mission, and we will give an overview of the currently identified technology needs and instrument predevelopments.

  13. Nonlinear Landau damping in the ionosphere

    NASA Technical Reports Server (NTRS)

    Kiwamoto, Y.; Benson, R. F.

    1978-01-01

    A model is presented to explain the non-resonant waves which give rise to the diffuse resonance observed near 3/2 f sub H by the Alouette and ISIS topside sounders, where f sub H is the ambient electron cyclotron frequency. In a strictly linear analysis, these instability driven waves will decay due to Landau damping on a time scale much shorter than the observed time duration of the diffuse resonance. Calculations of the nonlinear wave particle coupling coefficients, however, indicate that the diffuse resonance wave can be maintained by the nonlinear Landau damping of the sounder stimulated 2f sub H wave. The time duration of the diffuse resonance is determined by the transit time of the instability generated and nonlinearly maintained diffuse resonance wave from the remote short lived hot region back to the antenna. The model is consistent with the Alouette/ISIS observations, and clearly demonstrates the existence of nonlinear wave-particle interactions in the ionosphere.

  14. Submillimeter Planetary Atmospheric Chemistry Exploration Sounder

    NASA Technical Reports Server (NTRS)

    Schlecht, Erich T.; Allen, Mark A.; Gill, John J.; Choonsup, Lee; Lin, Robert H.; Sin, Seth; Mehdi, Imran; Siegel, Peter H.; Maestrini, Alain

    2013-01-01

    Planetary Atmospheric Chemistry Exploration Sounder (SPACES), a high-sensitivity laboratory breadboard for a spectrometer targeted at orbital planetary atmospheric analysis. The frequency range is 520 to 590 GHz, with a target noise temperature sensitivity of 2,500 K for detecting water, sulfur compounds, carbon compounds, and other atmospheric constituents. SPACES is a prototype for a powerful tool for the exploration of the chemistry and dynamics of any planetary atmosphere. It is fundamentally a single-pixel receiver for spectral signals emitted by the relevant constituents, intended to be fed by a fixed or movable telescope/antenna. Its front-end sensor translates the received signal down to the 100-MHz range where it can be digitized and the data transferred to a spectrum analyzer for processing, spectrum generation, and accumulation. The individual microwave and submillimeter wave components (mixers, LO high-powered amplifiers, and multipliers) of SPACES were developed in cooperation with other programs, although with this type of instrument in mind. Compared to previous planetary and Earth science instruments, its broad bandwidth (approx. =.13%) and rapid tunability (approx. =.10 ms) are new developments only made possible recently by the advancement in submillimeter circuit design and processing at JPL.

  15. The Atmospheric Infrared Sounder- An Overview

    NASA Technical Reports Server (NTRS)

    Larnbrigtsen, Bjorn; Fetzer, Eric; Lee, Sung-Yung; Irion, Fredrick; Hearty, Thomas; Gaiser, Steve; Pagano, Thomas; Aumann, Hartmut; Chahine, Moustafa

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) was launched in May 2002. Along with two companion microwave sensors, it forms the AIRS Sounding Suite. This system is the most advanced atmospheric sounding system to date, with measurement accuracies far surpassing those available on current weather satellites. The data products are calibrated radiances from all three sensors and a number of derived geophysical parameters, including vertical temperature and humidity profiles, surface temperature, cloud fraction, cIoud top pressure, and profiles of ozone. These products are generated under cloudy as well as clear conditions. An ongoing calibration validation effort has confirmed that the system is very accurate and stable, and many of the geophysical parameters have been validated. AIRS is in some cases more accurate than any other source and can therefore be difficult to validate, but this offers interesting new research opportunities. The applications for the AIRS products range from numerical weather prediction to atmospheric research - where the AIRS water vapor products near the surface and in the mid to upper troposphere will make it possible to characterize and model phenomena that are key for short-term atmospheric processes, such as weather patterns, to long-term processes, such as interannual cycles (e.g., El Nino) and climate change.

  16. DUst Sounder and Temperature Imager Experiment (DUSTIE)

    NASA Astrophysics Data System (ADS)

    McHugh, M. J.; Fish, C. S.; Taylor, M. J.; Gordley, L. L.; Hervig, M. E.; Summers, M. E.; Siskind, D. E.

    2009-12-01

    The Dust Sounder and Temperature Imager Experiment (DUSTIE) is a proposed CubeSat mission to determine the global distribution of cosmic smoke in the atmosphere. The Earth is under continual bombardment by comets and meteoroids. Over the last 5 billion years they have brought water and the basics of life to our planet. Today they are vaporized during atmospheric entry and deposited as microscopic smoke particles in the upper atmosphere. These cosmic particles are known to be important in a host of atmospheric processes, including nucleation of ice particles, ion chemistry in the thermosphere and heterogeneous chemistry in the mesosphere. Despite this, our current understanding is based on scant observations and theory. The successful deployment of DUSTIE will offer a major advance in this important emerging area of research. DUSTIE will use a digital camera to image the Sun at 0.420 µm during spacecraft sunrise and sunset. This will provide measurements to characterize the smoke distribution over the altitude range of ~40 to 90 km. A high-inclination orbit will provide near-global coverage monthly. Simultaneous refraction measurements will yield atmospheric density profiles up to 75 km. Measured smoke extinctions will be used to derive smoke particle volume and surface area densities. DUSTIE will utilize a 3U form factor CubeSat and rely heavily upon commercial-off-the-shelf (COTS) components and proven technologies.

  17. The processing of electron density profiles from the Mars Express MARSIS topside sounder

    NASA Astrophysics Data System (ADS)

    Morgan, D. D.; Witasse, O.; Nielsen, E.; Gurnett, D. A.; Duru, F.; Kirchner, D. L.

    2013-05-01

    here present a manual for the reduction of data from ionograms obtained from the Mars Express MARSIS Active Ionospheric Sounding topside radar sounder. Sample data are presented with the procedure for processing them explained as simply as possible. We discuss the uncertainties inherent in the measurements as well as systematic problems with the data. A sample code is included to facilitate the inversion process. We also include a comparison with an electron density profile taken from the Mars Express Radio Science occultation experiment, showing agreement between the two methods, although the data are not simultaneous.

  18. Ionospheric specification with analytical profilers: Evidences of non-Chapman electron density distribution in the upper ionosphere

    NASA Astrophysics Data System (ADS)

    Verhulst, T.; Stankov, S. M.

    2015-04-01

    In relation to the development of an operational ionospheric monitoring and imaging system, the most frequently used analytical ionospheric profilers (Chapman, Epstein, Exponential) were investigated in terms of suitability for topside ionosphere modelling. For the purpose, topside sounder measurements onboard Alouette and ISIS satellites have been analysed. We have come to the conclusion that the use of the Chapman profiler should be exercised with precaution as there are evidences that there are conditions when other profilers are better fit for modelling purposes. This is highlighted during ionospheric disturbances (e.g. during geomagnetic storms), when the shape of the topside electron density distribution might be better described by an Epstein profiler rather than a Chapman profiler.

  19. A computer based ionospheric sounding and HF noise measuring system

    NASA Astrophysics Data System (ADS)

    Earl, G. F.

    1980-09-01

    A system for the automated collection of ionospheric backscatter sounding and HF noise measurement data is described. The system was configured around a PDP 11/40 minicomputer and modified Barry Research FMCW sounding equipment. The real time digital signal processing associated with the backscatter sounder and noise measurement systems is discussed. The data are displayed and recorded in a calibrated mode, and examples are presented.

  20. Application of ionospheric topside-sounding results to magnetospheric physics and astrophysics

    NASA Astrophysics Data System (ADS)

    Benson, Robert F.; Osherovich, Vladimir A.

    2004-01-01

    A brief review is presented to illustrate how the knowledge and experience gained from investigations of ionospheric topside-sounder ionograms has benefited scientific research beyond the ionosphere. In particular, to the interpretation of (1) natural radio emissions from space plasmas, (2) sounder-stimulated echoes and plasma emissions, and plasma diagnostics in planetary magnetospheres and (3) X-ray spectra of disks around neutron stars and black holes. The relevant data are from 60 satellite years of ionospheric topside-sounder operations by the four satellites of the International Satellites for Ionospheric Studies (ISIS) program from 1963 through 1989. Not all of these data were reduced to ionograms on 35-mm film. An ongoing effort at the NASA Goddard Space Flight Center is producing digital topside-sounder ionograms directly from a selected subset of the original telemetry tapes. More than 300,000 digital ionograms are now in the National Space Science Data Center at the NASA GSFC (http://nssdc.gsfc.nasa.gov/space/isis/isis-status.html).

  1. Ultraspectral Infrared Measurements from the Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas

    2003-01-01

    Aqua measures the Earth's water cycle, energy fluxes, vegetation and temperatures. The Atmospheric Infrared Sounder (AIRS), Advanced Microwave Sounding Unit (AMSU) and Humidity Sounder for Brazil (HSB) were launched on the EOS Aqua spacecraft in May 2002. AIRS has had good radiometric and spectral sensitivity, stability, and accuracy and is suitable for climate studies. Temperature products compare well with radiosondes and models over the limited test range (|LAT| less than 40 degrees). Early trace gas products demonstrate the potential of AIRS. NASA is developing the next generation of hyperspectral IR imagers. JPL is ready to participate with US government agencies and US industry to transfer AIRS technology and science experience.

  2. Multipoint Geospace Science in 3D: The Paired Ionosphere-Thermosphere Orbiters(PITO) Mission

    NASA Technical Reports Server (NTRS)

    Clemmons, J.; Walterscheid, R.; Nigg, D.; Judnick, D.; Lang, J.; Spann, J.

    2010-01-01

    The science enabled by the Paired Ionosphere-Thermosphere Orbiters (PITO) mission is described and discussed. PITO has been designed to provide the concurrent, three-dimensional, multipoint measurements needed to advance geospace science while staying within a stringent resource envelope. The mission utilizes a pair of orbiting vehicles in eccentric, high-inclination, coplanar orbits. The orbits have arguments of perigee that differ by 180 degrees and are phased such that one vehicle is at perigee (200 km) while the second is at apogee (2000 km). Half an orbit later, the vehicles switch positions. Three complementary types of measurements exploit this scenario: local, in-situ measurements on both satellites, two-dimensional imaging from the higher satellite, and vertical sounders. The main idea is that two-dimensional context information for the low-altitude measurements is obtained by the high altitude imagers, while information on the third dimension is provided by vertical profiling. Such an observation system is capable of providing elements of global coverage, regional coverage, and concurrent coverage in three dimensions. Science goals are presented, as are the results of a detailed implementation plan, including several trade studies on key elements of the mission. The conclusion is that the mission would enable significant new understanding of the ionosphere-thermosphere system within a resource envelope that is consistent with that of NASA's Medium Explorer (MIDEX) line of science missions.

  3. Sounder stimulated D(sub n) resonances in Jupiter's Io plasma torus

    NASA Technical Reports Server (NTRS)

    Osherovich, V. A.; Benson, R. F.; Fainberg, J.; Stone, R. G.; Macdowall, R. J.

    1993-01-01

    On February 8, 1992, the Ulysses spacecraft passed through Jupiter's Io plasma torus, where rich spectra of narrow-band resonances were stimulated by the relaxation sounder of the Ulysses unified radio and plasma wave (URAP) instrument. Since the gyrofrequency f(sub g) is comparable to the plasma frequency f(sub p) in the Io torus, it was predicted that the general classification of stimulated ionospheric D(sub n) resonances, developed for 1 is less than or equal to f(sub p)/f(sub g) is less than or equal to 8 in the Earth's topside ionosphere, should apply in the Io torus as well as the Earth's magnetosphere (Osherovich, 1989). The URAP plasmagrams (sounder spectra) in the portions of the Io torus satisfying these plasma conditions are dominated by the D(sub n) resonances for frequencies below f(sub p). On most of these plasmagrams the f(sub p) resonance is also present, but it is seldom the dominant resonance. Neither upper hybrid nor nf(sub g) resonances have been found on these plasmagrams. The identification of D(sub n) resonances has allowed both the electron density and the magnetic field amplitude to be calculated. The derived densities on the outbound pass agree well with a Voyager model of Bagenal (1992). The derived magnetic field values are close to the Goddard Space Flight Center O(sub 6) magnetic field model.

  4. Assessment of error propagation in ultraspectral sounder data via JPEG2000 compression and turbo coding

    NASA Astrophysics Data System (ADS)

    Olsen, Donald P.; Wang, Charles C.; Sklar, Dean; Huang, Bormin; Ahuja, Alok

    2005-08-01

    Research has been undertaken to examine the robustness of JPEG2000 when corrupted by transmission bit errors in a satellite data stream. Contemporary and future ultraspectral sounders such as Atmospheric Infrared Sounder (AIRS), Cross-track Infrared Sounder (CrIS), Infrared Atmospheric Sounding Interferometer (IASI), Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS), and Hyperspectral Environmental Suite (HES) generate a large volume of three-dimensional data. Hence, compression of ultraspectral sounder data will facilitate data transmission and archiving. There is a need for lossless or near-lossless compression of ultraspectral sounder data to avoid potential retrieval degradation of geophysical parameters due to lossy compression. This paper investigates the simulated error propagation in AIRS ultraspectral sounder data with advanced source and channel coding in a satellite data stream. The source coding is done via JPEG2000, the latest International Organization for Standardization (ISO)/International Telecommunication Union (ITU) standard for image compression. After JPEG2000 compression the AIRS ultraspectral sounder data is then error correction encoded using a rate 0.954 turbo product code (TPC) for channel error control. Experimental results of error patterns on both channel and source decoding are presented. The error propagation effects are curbed via the block-based protection mechanism in the JPEG2000 codec as well as memory characteristics of the forward error correction (FEC) scheme to contain decoding errors within received blocks. A single nonheader bit error in a source code block tends to contaminate the bits until the end of the source code block before the inverse discrete wavelet transform (IDWT), and those erroneous bits propagate even further after the IDWT. Furthermore, a single header bit error may result in the corruption of almost the entire decompressed granule. JPEG2000 appears vulnerable to bit errors in a noisy channel of

  5. Global Daily Atmospheric State Profiles from the Atmospheric Infrared Sounder

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Aumann, Hartmut H.; Fetzer, Eric J.; Lambrigtsen, Bjorn H.; Chahine, Moustafa T.

    2008-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the EOS Aqua Spacecraft, launched on May 4, 2002. AIRS has 2378 infrared channels ranging from 3.7 (micro)m to 15.4 (micro)m and a 13.5 km footprint. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy on a global scale, as well as water vapor profiles, clouds, dust and trace gas amounts for CO2, CO, SO2, O3 and CH4.[1] AIRS data are used for weather forecasting and studies of global climate change. The AIRS is a 'facility' instrument developed by NASA as an experimental demonstration of advanced technology for remote sensing and the benefits of high resolution infrared spectra to science investigations.

  6. Ionospheric effects of magnetic storm observed by means of oblique sounding of artificial ionospheric turbulence

    NASA Astrophysics Data System (ADS)

    Uryadov, V. P.; Vertogradov, G. G.; Vertogradov, V. G.; Ponyatov, A. A.

    Results of experimental studies of the influence of the artificial ionospheric turbulence (AIT) on HF propagation are presented. Ionospheric modification and the creation of a scatterer was produced by powerful radio emission of the SURA heating facility (Nizhny Novgorod region). For diagnostics of the AIT were used the Russian chirp sounders network and HF Doppler radar. The reception of scattered signals was carried out in the Rostov-Don on the oblique V-type antenna oriented to the SURA heating facility. It is investigated ionospheric effects of magnetic storm during August 17-22, 2003 accompanied a period of the experiment. It is shown that ionospheric effects of the magnetic storm observed by means of Doppler frequency shift (DFS) measurements signals scattered from artificial small-scale field-aligned irregularities correlate well with the behavior of the southward component Bz of the interplanetary magnetic field and with variations in the geomagnetic field near the Earth surface. It has been found that at heights of the mid-latitude ionospheric F region under undisturbed conditions the electric field and the drift velocity of irregularities correspond to the typical values about 1 mV m-1 and 20 m s-1, respectively. During magnetic storm these values increase up to values of about 8.6 mV m-1 and 186 m s-1, which better correspond to the values typical for the high-latitude ionosphere. It is found that in the magnetically-disturbed period sporadically appearing trains with quasi-periodical modulation of DFS for the scattered signal with a period of ˜ 40-60 s and amplitude reaching 2 Hz were observed. The relation of the quasi-periodical oscillations of the DFS for the scattered signal to the presence of magnetohydrodynamics waves excited during a magnetic storm is considered. It is concluded that use HF Doppler radar for AIT sounding is of interest for diagnostics of wave processes in the ionosphere and magnetosphere. The conditions of formation of the HF

  7. ISIS topside-sounder Plasma-wave investigations as guides to desired Virtual Wave Observatory (VWO) data search capabilities

    NASA Astrophysics Data System (ADS)

    Benson, R. F.; Fung, S. F.

    2008-12-01

    Many plasma-wave phenomena, observed by space-borne radio sounders, cannot be properly explained in terms of wave propagation in a cold plasma consisting of mobile electrons and infinitely massive positive ions. These phenomena include signals known as plasma resonances. The principal resonances at the harmonics of the electron cyclotron frequency, the plasma frequency, and the upper-hybrid frequency are well explained by the warm-plasma propagation of sounder-generated electrostatic waves. Other resonances have been attributed to sounder-stimulated plasma instability and non-linear effects, eigenmodes of cylindrical electromagnetic plasma oscillations, and plasma memory processes. Data from the topside sounders of the International Satellites for Ionospheric Studies (ISIS) program played a major role in these interpretations. A data transformation and preservation effort at the Goddard Space Flight Center has produced digital ISIS topside ionograms and a metadata search program that has enabled some recent discoveries pertaining to the physics of these plasma resonances. For example, data records were obtained that enabled the long-standing question (several decades) of the origin of the plasma resonance at the fundamental electron cyclotron frequency to be explained [Muldrew, Radio Sci., 2006]. These data-search capabilities, and the science enabled by them, will be presented as a guide to desired data search capabilities to be included in the Virtual Wave Observatory (VWO).

  8. ISIS Topside-Sounder Plasma-Wave Investigations as Guides to Desired Virtual Wave Observatory (VWO) Data Search Capabilities

    NASA Technical Reports Server (NTRS)

    Benson, Robert F.; Fung, Shing F.

    2008-01-01

    Many plasma-wave phenomena, observed by space-borne radio sounders, cannot be properly explained in terms of wave propagation in a cold plasma consisting of mobile electrons and infinitely massive positive ions. These phenomena include signals known as plasma resonances. The principal resonances at the harmonics of the electron cyclotron frequency, the plasma frequency, and the upper-hybrid frequency are well explained by the warm-plasma propagation of sounder-generated electrostatic waves, Other resonances have been attributed to sounder-stimulated plasma instability and non-linear effects, eigenmodes of cylindrical electromagnetic plasma oscillations, and plasma memory processes. Data from the topside sounders of the International Satellites for Ionospheric Studies (ISIS) program played a major role in these interpretations. A data transformation and preservation effort at the Goddard Space Flight Center has produced digital ISIS topside ionograms and a metadata search program that has enabled some recent discoveries pertaining to the physics of these plasma resonances. For example, data records were obtained that enabled the long-standing question (several decades) of the origin of the plasma resonance at the fundamental electron cyclotron frequency to be explained [Muldrew, Radio Sci., 2006]. These data-search capabilities, and the science enabled by them, will be presented as a guide to desired data search capabilities to be included in the Virtual Wave Observatory (VWO).

  9. LAWS (Laser Atmospheric Wind Sounder) earth observing system

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Wind profiles can be measured from space using current technology. These wind profiles are essential for answering many of the interdisciplinary scientific questions to be addressed by EOS, the Earth Observing System. This report provides guidance for the development of a spaceborne wind sounder, the Laser Atmospheric Wind Sounder (LAWS), discussing the current state of the technology and reviewing the scientific rationale for the instrument. Whether obtained globally from the EOS polar platform or in the tropics and subtropics from the Space Station, wind profiles from space will provide essential information for advancing the skill of numerical weather prediction, furthering knowledge of large-scale atmospheric circulation and climate dynamics, and improving understanding of the global biogeochemical and hydrologic cycles. The LAWS Instrument Panel recommends that it be given high priority for new instrument development because of the pressing scientific need and the availability of the necessary technology. LAWS is to measure wind profiles with an accuracy of a few meters per second and to sample at intervals of 100 km horizontally for layers km thick.

  10. Ionosphere-reflected propagation

    NASA Technical Reports Server (NTRS)

    Reddy, B. M.

    1979-01-01

    The predictability of those ionospheric parameters relevant to ionosphere-reflected communications is considered along with their optimum utilization. Several excellent original articles and review papers which have been published from time to time dealing with the long term and short term forecasting of ionospheric parameters, radio systems, and modelling needs for ionospheric communications, are covered.

  11. On spread-F in the ionosphere before earthquakes

    NASA Astrophysics Data System (ADS)

    Liperovskaya, E. V.; Liperovsky, V. A.; Silina, A. S.; Parrot, M.

    2006-01-01

    Occurrence probability of the ionospheric spread-F in connection with earthquakes is analyzed. The F-layer is not close to the Earth (˜400 km), but in situ data could be obtained either by ionospheric sounders or by satellites. Data from the two Japanese ionospheric stations Kokubunji and Akita have been analyzed to find out long-term (a few weeks) variations of spread-F before and after earthquakes. Earthquakes with magnitudes M>5 were taken into account. Only time intervals where geomagnetic variations are weak have been analyzed. It is shown that the probability of spread-F observations starts to decrease approximately 40 days before earthquakes, presents a minimum about 10 days before and then takes 1 month to recover the background level (therefore this increase lasts about 3 weeks after earthquakes). This effect exists if the distance between epicenters and the sounding station is less than 500 km.

  12. A case study of a density structure over a vertical magnetic field region in the Martian ionosphere

    NASA Astrophysics Data System (ADS)

    Duru, F.; Gurnett, D. A.; Diéval, C.; Morgan, D. D.; Pisa, D.; Lundin, R.

    2016-05-01

    One of the discoveries made by the radar sounder on the Mars Express spacecraft is the existence of magnetically controlled structures in the ionosphere of Mars, which result in bulges in the ionospheric electron density contours. These bulges lead in turn to oblique echoes, which show up as hyperbola-shaped features in the echograms. A hyperbola-shaped feature observed over an isolated region of strong crustal magnetic field is associated with a plasma cavity in the upper ionosphere and a corresponding density enhancement in the lower levels of the ionosphere. We suggest that along open magnetic field lines, the solar wind electrons are accelerated downward and the ionospheric ions are accelerated upward in a manner similar to the field line-driven auroral acceleration at Earth. This heating due to precipitating electrons may cause an increase in the scale height and may drive a loss of ionospheric plasma at high altitudes.

  13. Space View Issues for Hyperspectral Sounders

    NASA Technical Reports Server (NTRS)

    Manning, Evan M.; Aumann, Hartmut H.; Broberg, Steven E.

    2013-01-01

    The expectation for climate quality measurements from hyperspectral sounders is absolute calibration accuracy at the 100 mK level and stability at the < 40 mK/decade level. The Atmospheric InfraRed Sounder (AIRS)1, Cross-track Infrared Sounder (CrIS), and Infrared Atmospheric Sounding Interferometer (IASI) hyperspectral sounders currently in orbit have been shown to agree well over most of their brightness temperature range. Some larger discrepancies are seen, however, at the coldest scene temperatures, such as those seen in Antarctic winter and deep convective clouds. A key limiting factor for the calibrated scene radiance accuracy for cold scenes is how well the effective radiance of the cold space view pertains to the scene views. The space view signal is composed of external sources and instrument thermal emission at about 270 K from the scan mirror, external baffles, etc. Any difference in any of these contributions between space views and scene views will impact the absolute calibration accuracy, and the impact can be critical for cold scenes. Any change over time in these will show up as an apparent trend in calibrated radiances. We use AIRS data to investigate the validity of the space view assumption in view of the 100 mK accuracy and 40 mK/decade trend expectations. We show that the space views used for the cold calibration point for AIRS v5 Level-1B products meet these standards except under special circumstances and that AIRS v6 Level-1B products will meet them under all circumstances. This analysis also shows the value of having multiple distinct space views to give operational redundancy and analytic data, and that reaching climate quality requires continuing monitoring of aging instruments and adjustment of calibration.

  14. Radiometric consistency assessment of hyperspectral infrared sounders

    NASA Astrophysics Data System (ADS)

    Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

    2015-07-01

    The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark datasets for both inter-calibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and -B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through one year of simultaneous nadir overpass (SNO) observations to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the longwave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both Polar and Tropical SNOs. The combined global SNO datasets indicate that, the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 comparison spectral regions and they range from 0.15 to 0.21 K in the remaining 4 spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

  15. Radiometric consistency assessment of hyperspectral infrared sounders

    NASA Astrophysics Data System (ADS)

    Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

    2015-11-01

    The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark data sets for both intercalibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and MetOp-B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through simultaneous nadir overpass (SNO) observations in 2013, to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the long-wave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both polar and tropical SNOs. The combined global SNO data sets indicate that the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 spectral regions and they range from 0.15 to 0.21 K in the remaining four spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

  16. VAS demonstration: (VISSR Atmospheric Sounder) description

    NASA Technical Reports Server (NTRS)

    Montgomery, H. E.; Uccellini, L. W.

    1985-01-01

    The VAS Demonstration (VISSR Atmospheric Sounder) is a project designed to evaluate the VAS instrument as a remote sensor of the Earth's atmosphere and surface. This report describes the instrument and ground processing system, the instrument performance, the valiation as a temperature and moisture profiler compared with ground truth and other satellites, and assesses its performance as a valuable meteorological tool. The report also addresses the availability of data for scientific research.

  17. 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.

  18. 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.

  19. The terrestrial ionosphere

    NASA Technical Reports Server (NTRS)

    Schunk, R. W.

    1983-01-01

    The theory relating to the basic physics governing the behavior of the terrestrial ionosphere is reviewed. The review covers the coupling of the ionosphere to both the neutral atmosphere and magnetosphere, the creation and transport of ionization in the ionosphere, and the ionospheric thermal structure. The review also covers the variation of the ionosphere with altitude, latitude, longitude, universal time, season, solar cycle, and geomagnetic activity. In addition, some unique ionospheric features are discussed, such as the polar ionization hole, the main electron density trough, the ion temperature hot spots, the high-latitude ionization tongue, the equatorial fountain, Appleton's peaks, and the polar wind.

  20. Ionospheric and satellite observations for studying the dynamic behavior of typhoons and the detection of severe storms and tsunamis

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Smith, R. E.

    1978-01-01

    Atmospheric acoustic-gravity waves associated with severe thunderstorms, tornadoes, typhoons (hurricanes) and tsunamis can be studied through the coupling between the ionosphere and the troposphere. Reverse ray tracing computations of acoustic-gravity waves observed by an ionospheric Doppler sounder array show that wave sources are in the nearby storm systems and that the waves are excited prior to the storms. Results show that ionospheric observations, together with satellite observations, can contribute to the understanding of the dynamical behavior of typhoons, severe storms and tsunamis.

  1. 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.

  2. Radar signal propagation through the ionosphere of Europa

    NASA Astrophysics Data System (ADS)

    Grima, Cyril; Blankenship, Donald D.; Schroeder, Dustin M.

    2015-11-01

    We review the current state of knowledge of the Europan plasma environment, its effects on radio wave propagation, and its impact on the performance and design of future radar sounders for the exploration of Europa's ice crust. The Europan ionosphere is produced in two independently-rotating hemispheres by photo-ionization of the neutral exosphere and interaction with the Io plasma torus, respectively. This combination is responsible for temporal and longitudinal ionospheric heterogeneities not well constrained by observations. When Europa's ionosphere is active, the maximum cut-off frequency is 1 MHz at the surface. The main impacts on radar signal propagation are dispersive phase shift and Faraday rotation, both a function of the total electron content (up to 4×1015 m-2) and the Jovian magnetic field strength at Europa (~420 nT). The severity of these impacts decrease with increasing center frequency and increase with altitude, latitude, and bandwidth. The 9 MHz channels on the Radar for Icy Moons Exploration (RIME) and proposed Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) will be sensitive to the Europan ionosphere. For these or similar radar sounders, the ionospheric signal distortion from dispersive phase shift can be corrected with existing techniques, which would also enable the estimation of the total electron content below the spacecraft. At 9 MHz, the Faraday fading is not expected to exceed 6 dB under the worst conditions. At lower frequencies, any active or passive radio probing of the ice shell exploration would be limited to frequencies above 1-8 MHz (depending on survey configuration) below which Faraday rotation angle would lead to signal fading and detection ambiguity. Radar instruments could be sensitive to neutrals and electrons added in the exosphere from any plume activity if present.

  3. 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.

  4. Preliminary validation of the refractivity from the new radio occultation sounder GNOS/FY-3C

    NASA Astrophysics Data System (ADS)

    Liao, Mi; Zhang, Peng; Yang, Guang-Lin; Bi, Yan-Meng; Liu, Yan; Bai, Wei-Hua; Meng, Xiang-Guang; Du, Qi-Fei; Sun, Yue-Qiang

    2016-03-01

    As a new member of the space-based radio occultation sounders, the GNOS (Global Navigation Satellite System Occultation Sounder) mounted on Fengyun-3C (FY-3C) has been carrying out atmospheric sounding since 23 September 2013. GNOS takes approximately 800 daily measurements using GPS (Global Positioning System) and Chinese BDS (BeiDou navigation satellite) signals. In this work, the atmospheric refractivity profiles from GNOS were compared with the ones obtained from the co-located ECMWF (European Centre for Medium-Range Weather Forecasts) reanalysis. The mean bias of the refractivity obtained through GNOS GPS (BDS) was found to be approximately -0.09 % (-0.04 %) from the near surface to up to 46 km. While the average standard deviation was approximately 1.81 % (1.26 %), it was as low as 0.75 % (0.53 %) in the range of 5-25 km, where best sounding results are usually achieved. Further, COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) and MetOp/ GRAS (GNSS Receiver for Atmospheric Sounding) radio occultation data were compared with the ECMWF reanalysis; the results thus obtained could be used as reference data for GNOS. Our results showed that GNOS/FY-3C meets the design requirements in terms of accuracy and precision of the sounder. It possesses a sounding capability similar to COSMIC and MetOp/GRAS in the vertical range of 0-30 km, though it needs further improvement above 30 km. Overall, it provides a new data source for the global numerical weather prediction (NWP) community.

  5. Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory`s Source Region Program. Appendix D: Ionospheric measurements for IVEs

    SciTech Connect

    Fitzgerald, T.J.; Carlos, R.C.; Argo, P.E.

    1993-01-21

    As part of the integrated verification experiment (IVE), we deployed a network of hf ionospheric sounders to detect the effects of acoustic waves generated by surface ground motion following underground nuclear tests at the Nevada Test Site. The network sampled up to four geographic locations in the ionosphere from almost directly overhead of the surface ground zero out to a horizontal range of 60 km. We present sample results for four of the IVEs: Misty Echo, Texarkana, Mineral Quarry, and Bexar.

  6. Mars ionosphere: A review of experimental results and modeling studies

    NASA Astrophysics Data System (ADS)

    Haider, S. A.; Mahajan, K. K.; Kallio, E.

    2011-10-01

    In this paper we review results from atmospheric and ionospheric experiments on the early planetary missions like the Mariners, Mars, and Viking 1 and 2 Orbiters/Landers. We then discuss the new results obtained from the two latest missions, namely, the Mars Global Surveyor (MGS) and Mars Express (MEX). The MGS had three ionospheric and atmospheric related experiments, namely, (1) the radio science experiment, which generated 5600 electron density profiles covering a major portion of sunspot cycle 23; (2) the magnetometer/electron reflectometer experiment, which very clearly answered the question about the presence or absence of Martian intrinsic magnetic field; and (3) the accelerometer experiment, which provided a large database of atmospheric density at various Martian locations during the aerobraking phases. The topside sounder on the MEX provided electron density profiles for altitudes above the primary ionospheric peak with a very high time resolution, thereby providing opportunity for exploring ionospheric conditions during events of rapid changes like solar flares. Unlike Venus, where simultaneous electron density, ion density, and magnetic field measurements were made, Mars lacks this kind of information. Consequently, most of our current understanding of Mars' plasma environment is based on theoretical models. We therefore review the various atmospheric and ionospheric models for Mars, which have been generated during the last 4 decades.

  7. Energetic Particle-Driven ULF Waves in the Ionosphere

    NASA Astrophysics Data System (ADS)

    Yeoman, T. K.; James, M. K.; Klimushkin, D. Yu.; Mager, P. N.

    2016-02-01

    Ionospheric radar systems have proved to be a powerful tool for the investigation of magnetospheric ULF waves. High-m poloidal waves become much more attenuated in ground magnetometer data than low-m toroidal waves. For this reason ionospheric radar systems have been effective in the study of high-m poloidal waves driven by energetic particle populations within the magnetosphere, and it is this class of ULF waves that is discussed in this chapter. More recent ionospheric observations of high-m ULF waves have taken advantage of the Super Dual Auroral Radar Network (SuperDARN). SuperDARN is a global array of high-frequency (HF) radars. In a Doppler sounder, use is made of the direct reflection of a radio wave from the ionosphere, rather than a scattering process. A number of alternative techniques are available for exploring the ionospheric signatures of such wave events, which are relatively underexploited, and have the potential to provide important new observations.

  8. Preliminary validation of refractivity from a new radio occultation sounder GNOS/FY-3C

    NASA Astrophysics Data System (ADS)

    Liao, M.; Zhang, P.; Yang, G. L.; Bi, Y. M.; Liu, Y.; Bai, W. H.; Meng, X. G.; Du, Q. F.; Sun, Y. Q.

    2015-09-01

    As a new member of space-based radio occultation sounder, the GNOS (Global Navigation Satellite System Occultation Sounder) mounted on FY-3C has been carrying out the atmospheric sounding since 23 September 2013. GNOS takes a daily measurement up to 800 times with GPS (Global Position System) and Chinese BDS (BeiDou navigation satellite) signals. The refractivity profiles from GNOS are compared with the co-located ECMWF (European Centre for Medium-Range Weather Forecasts) analyses in this paper. Bias and standard deviation have being calculated as the function of altitude. The mean bias is about 0.2 % from the near surface to 35 km. The average standard deviation is within 2 % while it is down to about 1 % in the range 5-30 km where best soundings are usually made. To evaluate the performance of GNOS, COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) and GRAS/METOP-A (GNSS Receiver for Atmospheric Sounding) data are also compared to ECMWF analyses as the reference. The results show that GNOS/FY-3C meets the requirements of the design well. It possesses a sounding capability similar to COSMIC and GRAS in the vertical range of 0-30 km, though it needs improvement in higher altitude. Generally, it provides a new data source for global NWP (numerical weather prediction) community.

  9. Laser Atmospheric Wind Sounder (LAWS) performance analysis

    NASA Technical Reports Server (NTRS)

    Kenyon, D.; Petheram, J.

    1991-01-01

    The science objectives of the NASA's Laser Atmospheric Sounder (LAWS) are discussed, and results of the performance analysis of the LAWS system are presented together with the instrument configuration used for these performance analyses. The results of analyses show that the science requirements for the wind-velocity accuracies of m/sec in the lower troposphere and 5 m/sec in the upper troposphere will be met by the present design of the LAWS system. The paper presents the performance estimates of the LAWS in terms of the global coverage, spatial resolution, signal-to-noise ratio, line-of-sight velocity error, and horizontal inversion accuracy.

  10. Coupling of ionosphere and troposphere during the occurrence of isolated tornadoes on November 20, 1973

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Phan, T.; Smith, R. E.

    1979-01-01

    The paper examines the coupling between the ionosphere and the troposphere during time periods with isolated tornadoes on the stormy day of November 20, 1973. Observations are made with a high-frequency CW Doppler array system, in which radio receivers located at a central site monitored signals transmitted from three independent remote sites on three sets of frequencies (4.0125, 4.759, 5.734 MHz) and reflected off the ionosphere approximately halfway between the transmitter and receiver sites. It is shown that the sources of the gravity waves associated with tornadoes are always on the squall lines and near the tornado touchdown locations, and that analyses of ionospheric Doppler sounder observations of medium-scale gravity waves can contribute to the understanding of the coupling between the ionosphere and the troposphere during periods of severe storm activity.

  11. Multisensor profiling of a concentric gravity wave event propagating from the troposphere to the ionosphere

    NASA Astrophysics Data System (ADS)

    Azeem, Irfan; Yue, Jia; Hoffmann, Lars; Miller, Steven D.; Straka, William C.; Crowley, Geoff

    2015-10-01

    In this paper, we present near-simultaneous observations of a gravity wave (GW) event in the stratosphere, mesosphere, and ionosphere over the South Central United States and track it from its convective source region in the troposphere to the ionosphere, where it appears as a traveling ionospheric disturbance (TID). On 4 April 2014 concentric GW ring patterns were seen at stratospheric heights in close proximity to a convective storm over North Texas in the Atmospheric Infrared Sounder data on board the NASA Aqua satellite. Concentric GWs of similar orientation and epicenter were also observed in mesospheric nightglow measurements of the Day/Night Band of the Visible/Infrared Imaging Radiometer Suite on the Suomi National Polar-orbiting Partnership satellite. Concentric TIDs were seen in total electron content data derived from ground-based GPS receivers distributed throughout the U.S. These new multisensor observations of TIDs and atmospheric GWs can provide a unique perspective on ionosphere-atmosphere coupling.

  12. Propagation studies using a theoretical ionosphere model

    NASA Technical Reports Server (NTRS)

    Lee, M.

    1973-01-01

    The mid-latitude ionospheric and neutral atmospheric models are coupled with an advanced three dimensional ray tracing program to see what success would be obtained in predicting the wave propagation conditions and to study to what extent the use of theoretical ionospheric models is practical. The Penn State MK 1 ionospheric model, the Mitra-Rowe D region model, and the Groves' neutral atmospheric model are used throughout this work to represent the real electron densities and collision frequencies. The Faraday rotation and differential Doppler velocities from satellites, the propagation modes for long distance high frequency propagation, the group delays for each mode, the ionospheric absorption, and the spatial loss are all predicted.

  13. Coherent-array HF Doppler sounding of traveling ionospheric disturbances. I - Basic technique

    NASA Astrophysics Data System (ADS)

    Jacobson, A. R.; Carlos, R. C.

    1989-04-01

    The paper presents an introduction to the use of phase-coherent, multireceiver HF Doppler sounding arrays for measuring the horizontal velocity of traveling ionospheric disturbances (TIDs). The point of departure is the theorem of Pfister (1971) relating ray Doppler to ray zenith angle for a monostatic full reflection sounder. Retaining the simple model of a specular, smooth ionospheric reflector which is deformed by a propagating undulation, the theorem is first generalyzed to bistatic sounding geometry and then the effects of amplitude are included in addition to phase. Next, these results are cast into an algorithm for treating multireceiver phase sounders containing many diverse baselines, in order to obtain an accurate and unambiguous solution in the plane of wave slowness (inverse of velocity). The point spread function of this solution is controlled gy process bandwidth and by array geometry.

  14. View to the south with the Two Sounder Antennas on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View to the south with the Two Sounder Antennas on the left - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Four Sounder Antennas, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  15. Ionospheric and Geomagnetic Activity Investigated Using Oblique Sounding Comparisons With an HF Radio Propagation Model

    NASA Astrophysics Data System (ADS)

    Neudegg, D.; Layoun, M.; Hutchinson, S.

    2008-12-01

    Oblique HF sounder paths over ~2000km have been operating between New Zealand and Australia for a number of years. The maximum observed frequencies (MOF) are compared with predictions from the climatological HF radio skywave propagation model used by IPS. Variations from predicted median (MUF),lower (OWF) and upper decile frequencies may be interpreted in terms of ionospheric and geomagnetic activity and the effectiveness of parameterisation of ionospheric support for HF by the T-index examined. Closely spaced multiple paths provide opportunities to investigate small scale F2 layer structures.

  16. 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.

  17. Science Highlights and Lessons Learned from the Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Fetzer, Eric J.; Suda, Jarrod; Licata, Steve

    2011-01-01

    The Atmospheric Infrared Sounder (AIRS) and companion instrument, the Advanced Microwave Sounding Unit (AMSU) on the NASA Earth Observing System Aqua spacecraft are facility instruments designed to support measurements of atmospheric temperature, water vapor and a wide range of atmospheric constituents in support of weather forecasting and scientific research in climate and atmospheric chemistry. This paper is an update to the science highlights from a paper by the authors released last year and also looks back at the lessons learned and future needs of the scientific community. These lessons not only include requirements on the measurements, but scientific shortfalls as well. Results from the NASA Science Community Workshop in IR and MW Sounders relating to AIRS and AMSU requirements and concerns are covered and reflect much of what has been learned and what is needed for future atmospheric sounding from Low Earth Orbit.

  18. Propagation in the ionosphere, A

    NASA Astrophysics Data System (ADS)

    Cannon, Paul S.

    1994-09-01

    The use of ionospheric models and ray tracing models as components of a propagation model are discussed. These can be used as decision aids to support human interpretation of ionospheric propagation. The physical basis for ionospheric decision aids is introduced by reference to ionospheric morphology and the basic theory of ionospheric propagation, which, along with ray tracing techniques, is then reviewed.

  19. Regional Assimilation of NASA Atmospheric Infrared Sounder (AIRS) Data

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Lapenta, William; Jediovec, Gary J.; McCarty, William; Mecikalski, John R.

    2004-01-01

    The NASA Short-term Prediction Research and Transition (SPORT) Center seeks to accelerate the infusion of NASA Earth Science Enterprise (ESE) observations, data assimilation and modeling research into NW S forecast operations and decision-making. The Atmospheric Infrared Sounder (AIRS), is expected to advance climate research and weather prediction into the 21 st century. It is one of six instruments onboard Aqua, a satellite that is part of NASA s Earth Observing System. AIRS, along with two partner microwave sounding instruments, represents the most advanced atmospheric sounding system ever deployed in space. The system is capable of measuring the atmospheric temperature in the troposphere with radiosonde accuracies of 1 K over 1 km-thick layers under both clear and cloudy conditions, while the accuracy of the derived moisture profiles will exceed that obtained by radiosondes. It is imperative that the scientific community is prepared to take full advantage of next-generation satellite data that will become available within the next decade. The purpose of this paper is to describe a procedure designed to optimally assimilate AIRS data at high spatial resolution over both land and ocean. The assimilation system used in this study is the Local Analysis and Prediction System (LAPS) developed at the Forecast System Laboratory used extensively around the globe. Results will focus on quality control issues associated with AIRS, optimal assimilation strategies, and the impact of the AIRS data on subsequent numerical forecasts at 12 km produced by the next generation Weather Research and Forecast (WRF) model.

  20. RAWS: The spaceborne radar wind sounder

    NASA Astrophysics Data System (ADS)

    Moore, Richard K.

    1991-09-01

    The concept of the Radar Wind Sounder (RAWS) is discussed. The goals of the RAWS is to estimate the following three qualities: the echo power, to determine rain rate and surface wind velocity; the mean Doppler frequency, to determine the wind velocity in hydrometers; and the spread of the Doppler frequency, to determine the turbulent spread of the wind velocity. Researchers made significant progress during the first year. The feasibility of the concept seems certain. Studies indicate that a reasonably sized system can measure in the presence of ice clouds and dense water clouds. No sensitivity problems exist in rainy environments. More research is needed on the application of the radar to the measurement of rain rates and winds at the sea surface.

  1. Microwave limb sounder for stratospheric measurements

    NASA Astrophysics Data System (ADS)

    Waters, J. W.; Hardy, J. C.; Jarnot, R. F.; Pickett, H. M.; Zimmerman, P.

    1985-06-01

    The balloon-borne Microwave Limb Sounder (BMLS) measures atmospheric thermal emission from millimeter wavelength spectral lines to determine vertical profiles of stratospheric species. The instrument flown to data operates at 205 BHz to measure ClO, O3, and H2O2. A 63 GHz radiometer is added to test the technique for determining tangent point pressure from the MLS experiment on the Upper Atmosphere Research Satellite (UARS). Many additional species is also measured by the BLMS. A radiometer at 270 GHz would provide measurements of HO2, NO2, HNO3, N2O, 16O18O16O, and HCN. With this addition the BMLS can test the current theory of O3 heavy ozone photochemical balance in the upper stratosphere.

  2. EOS Laser Atmosphere Wind Sounder (LAWS) investigation

    NASA Technical Reports Server (NTRS)

    1996-01-01

    In this final report, the set of tasks that evolved from the Laser Atmosphere Wind Sounder (LAWS) Science Team are reviewed, the major accomplishments are summarized, and a complete set of resulting references provided. The tasks included preparation of a plan for the LAWS Algorithm Development and Evolution Laboratory (LADEL); participation in the preparation of a joint CNES/NASA proposal to build a space-based DWL; involvement in the Global Backscatter Experiments (GLOBE); evaluation of several DWL concepts including 'Quick-LAWS', SPNDL and several direct detection technologies; and an extensive series of system trade studies and Observing System Simulation Experiments (OSSE's). In this report, some of the key accomplishments are briefly summarized with reference to interim reports, special reports, conference/workshop presentations, and publications.

  3. Climate Change and Sounder Radiometric Stability

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Aumann, Hartmut H.; Manning, Evan

    2009-01-01

    Satellite instrument radiometric stability is critical for climate studies. The Atmospheric Infrared Sounder (AIRS) radiances are of sufficient stability and accuracy to serve as a climate data record as evidenced by comparisons with the global network of buoys. In this paper we examine the sensitivity of derived geophysical products to potential instrument radiometric stability issues due to diurnal, orbital and seasonal variations. Our method is to perturb the AIRS radiances and examine the impact to retrieved parameters. Results show that instability in retrieved temperature products will be on the same order of the brightness temperature error in the radiances and follow the same time dependences. AIRS excellent stability makes it ideal for examining impacts of instabilities of future systems on geophysical parameter performance.

  4. RAWS: The spaceborne radar wind sounder

    NASA Technical Reports Server (NTRS)

    Moore, Richard K.

    1991-01-01

    The concept of the Radar Wind Sounder (RAWS) is discussed. The goals of the RAWS is to estimate the following three qualities: the echo power, to determine rain rate and surface wind velocity; the mean Doppler frequency, to determine the wind velocity in hydrometers; and the spread of the Doppler frequency, to determine the turbulent spread of the wind velocity. Researchers made significant progress during the first year. The feasibility of the concept seems certain. Studies indicate that a reasonably sized system can measure in the presence of ice clouds and dense water clouds. No sensitivity problems exist in rainy environments. More research is needed on the application of the radar to the measurement of rain rates and winds at the sea surface.

  5. Assimilation of the Microwave Limb Sounder Radiances

    NASA Technical Reports Server (NTRS)

    Wargan, K.; Read, W.; Livesey, N.; Wagner, P.; Nguyen. H.; Pawson, S.

    2012-01-01

    It has been shown that the assimilation of limb-sounder data can significantly improve the representation of ozone in NASA's GEOS Data Assimilation Systems (GEOS-DAS), particularly in the stratosphere. The studies conducted so far utilized retrieved data from the MIPAS, POAM, ILAS and EOS Microwave Limb Sounder (EOS MLS) instruments. Direct assimilation of the radiance data can be seen as the natural next step to those studies. The motivation behind working with radiances is twofold. First, retrieval algorithms use a priori data which are either climatological or are obtained from previous analyses. This introduces additional uncertainty and, in some cases, may lead to "self-contamination"- when the a priori is taken from the same assimilation system in which subsequently ingests the retrieved observations. Second, radiances can be available in near real time thus providing an opportunity for operational assimilation, which could help improve the use of infrared radiance instruments from operational satellite instruments. In this presentation we summarize our ongoing work on an implementation of the assimilation of EOS MLS radiances into the GEOS-5 DAS. This work focuses on assimilation of band 7 brightness temperatures which are sensitive to ozone. Our implementation uses the MLS Callable Forward Model developed by the MLS team at NASA JPL as the observation operator. We will describe our approach and recent results which are not yet final. In particular, we will demonstrate that this approach has a potential to improve the vertical structure of ozone in the lower tropical stratosphere as compared with the retrieved MLS product. We will discuss the computational efficiency of this implementation.

  6. 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.

  7. First Data from Mars Climate Sounder

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The Mars Climate Sounder, an instrument on NASA's Mars Reconnaissance Orbiter designed to monitor daily changes in the global atmosphere of Mars, made its first observations of Mars on March 24, 2006.

    These tests were conducted to demonstrate that the instrument could, if needed, support the mission's aerobraking maneuvers (dips into the atmosphere to change the shape of the orbit) by providing hemisphere-scale coverage of atmospheric activity. The instrument scanned nine arrays of detectors four times across the entire disc of the planet, including the north pole, from an altitude of about 45,000 kilometers (28,000 miles). This is about 150 times farther away than the spacecraft will be during its main science phase. At this great range, the planet appears only 40 pixels wide, as suggested by the pixilation of the images. However, this is sufficient to identify regional dust storms in the lower atmosphere. Regional dust storms could perturb atmospheric densities at the higher altitudes (about 100 kilometers or 60 miles) where the orbiter will conduct more than 500 aerobraking passes during the next six months. Such storms are rare in the current season on Mars, early northern spring, and no large storms are present as the orbiter prepares for the start of aerobraking.

    Each of the Mars Climate Sounder's arrays looks in a different wavelength band, and three of the resulting images are shown here. The view on the left is from data collected in a broad spectral band (wavelengths of 0.3 microns to 3 microns) for reflected sunlight. The view in the center is from data collected in the 12-micron thermal-infrared band. This band was chosen to sense infrared radiation from the surface when the atmosphere is clear and from dust clouds when it is not. The view on the right is from data collected at 15 microns, a longer-wavelength band still in the thermal-infrared part of the spectrum. At this wavelength, carbon dioxide, the main ingredient in Mars

  8. Digital ionospheric sounding in the Arctic

    NASA Astrophysics Data System (ADS)

    Reinisch, B.; Bibl, K.

    1981-01-01

    New ionogram observation techniques were applied at the Goose Bay Ionospheric Observatory (GBIO) in Newfoundland, Canada, and aboard AFGL's Airborne Ionospheric Observatory (AIO), using the Digisonde 128PS system. A receiving array of four crossed-loop antennas at GBIO enabled incidence angle and polarization measurements within the ionogram in addition to the Doppler observations. The Doppler information in the propagation ionograms between the GBIO Digisonde and the moving AIO sounder facilitates the interpreting of different modes of propagation. Software for the AFGL CDC 6600 computer and for a microcomputer was developed for the processing of the digital ionograms. The identification of ordinary and extraordinary echoes in the Goose Bay ionograms greatly simplify the automatic processing of ionograms. Indeed, it became clear that for automatic ionogram trace identification the O and X tagging is a prerequisite. In support of the ESD 414L project an ionogram communicator (ICOM) was added to the GBIO Digisonde providing - via telephone lines - realtime ionogram printouts at the Over-The-Horizon Backscatter Experimental Radar System in Maine. Another Digisonde station was equipped and brought to operation in Keflavik, Iceland, to provide environmental data for the OTH radar operation.

  9. Estimation of volcanic ash refractive index from satellite infrared sounder data

    NASA Astrophysics Data System (ADS)

    Ishimoto, H.; Masuda, K.

    2014-12-01

    The properties of volcanic ash clouds (cloud height, optical depth, and effective radius of the particles) are planned to estimate from the data of the next Japanese geostationary meteorological satellite, Himawari 8/9. The volcanic ash algorithms, such as those proposed by NOAA/NESDIS and by EUMETSAT, are based on the infrared absorption properties of the ash particles, and the refractive index of a typical volcanic rock (i.e. andesite) has been used in the forward radiative transfer calculations. Because of a variety of the absorption properties for real volcanic ash particles at infrared wavelengths (9-13 micron), a large retrieval error may occur if the refractive index of the observed ash particles was different from that assumed in the retrieval algorithm. Satellite infrared sounder provides spectral information for the volcanic ash clouds. If we can estimate the refractive index of the ash particles from the infrared sounder data, a dataset of the optical properties for similar rock type of the volcanic ash can be prepared for the ash retrieval algorithms of geostationary/polar-orbiting satellites in advance. Furthermore, the estimated refractive index can be used for a diagnostic and a correction of the ash particle model in the retrieval algorithm within a period of the volcanic activities. In this work, optimal estimation of the volcanic ash parameters was conducted through the radiative transfer calculations for the window channels of the atmospheric infrared sounder (AIRS). The estimated refractive indices are proposed for the volcanic ash particles of some eruption events.

  10. Observations by the CUTLASS radar, HF Doppler, oblique ionospheric sounding, and TEC from GPS during a magnetic storm

    NASA Astrophysics Data System (ADS)

    Blagoveshchensky, D. V.; Lester, M.; Kornienko, V. A.; Shagimuratov, I. I.; Stocker, A. J.; Warrington, E. M.

    2005-07-01

    Multi-diagnostic observations, covering a significant area of northwest Europe, were made during the magnetic storm interval (28 29 April 2001) that occurred during the High Rate SolarMax IGS/GPS-campaign. HF radio observations were made with vertical sounders (St. Petersburg and Sodankyla), oblique incidence sounders (OIS), on paths from Murmansk to St. Petersburg, 1050 km, and Inskip to Leicester, 170 km, Doppler sounders, on paths from Cyprus to St. Petersburg, 2800 km, and Murmansk to St. Petersburg, and a coherent scatter radar (CUTLASS, Hankasalmi, Finland). These, together with total electron content (TEC) measurements made at GPS stations from the Euref network in northwest Europe, are presented in this paper. A broad comparison of radio propagation data with ionospheric data at high and mid latitudes, under quiet and disturbed conditions, was undertaken. This analysis, together with a geophysical interpretation, allow us to better understand the nature of the ionospheric processes which occur during geomagnetic storms. The peculiarity of the storm was that it comprised of three individual substorms, the first of which appears to have been triggered by a compression of the magnetosphere. Besides the storm effects, we have also studied substorm effects in the observations separately, providing an improved understanding of the storm/substorm relationship. The main results of the investigations are the following. A narrow trough is formed some 10h after the storm onset in the TEC which is most likely a result of enhanced ionospheric convection. An enhancement in TEC some 2 3 h after the storm onset is most likely a result of heating and upwelling of the auroral ionosphere caused by enhanced currents. The so-called main effect on ionospheric propagation was observed at mid-latitudes during the first two substorms, but only during the first substorm at high latitudes. Ionospheric irregularities observed by CUTLASS were clearly related to the gradient in TEC

  11. 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

  12. Response of the incompressible ionosphere to the compression of the magnetosphere during the geomagnetic sudden commencements

    NASA Astrophysics Data System (ADS)

    Kikuchi, T.; Hashimoto, K. K.; Tomizawa, I.; Ebihara, Y.; Nishimura, Y.; Araki, T.; Shinbori, A.; Veenadhari, B.; Tanaka, T.; Nagatsuma, T.

    2016-02-01

    The ionospheric plasma in midlatitude moves upward/downward during the geomagnetic sudden commencement causing the HF Doppler frequency changes; SCF (+ -) and (- +) on the dayside and nightside, respectively, except for the SCF (+ -) in the evening as found by Kikuchi et al. (1985). Although the preliminary and main frequency deviations (PFD, MFD) of the SCF have been attributed to the dusk-to-dawn and dawn-to-dusk potential electric fields, there still remain questions if the positive PFD can be caused by the compressional magnetohydrodynamic (MHD) wave and what causes the evening anomaly of the SCF. With the HF Doppler sounder, we show that the dayside ionosphere moves upward toward the Sun during the main impulse (MI) of the SC, when the compressional wave is supposed to push the ionosphere downward. The motion of the ionosphere is shown to be correlated with the equatorial electrojet, matching the potential electric field transmitted with the ionospheric currents from the polar ionosphere. We confirmed that the electric field of the compressional wave is severely suppressed by the conducting ionosphere and reproduced the SC electric fields using the global MHD simulation in which the potential solver is employed. The model calculations well reproduced the preliminary impulse and MI electric fields and their evening anomaly. It is suggested that the electric potential is transmitted from the polar ionosphere to the equator by the zeroth-order transverse magnetic (TM0) mode waves in the Earth-ionosphere waveguide. The near-instantaneous transmission of the electric potential leads to instantaneous global response of the incompressible ionosphere.

  13. Development and test of the Atmospheric Infrared Sounder (AIRS)

    NASA Astrophysics Data System (ADS)

    Morse, Paul G.; Bates, Jerry C.; Miller, Christopher R.; Chahine, Moustafa T.; O'Callaghan, Fred; Aumann, Hartmut H.; Karnik, Avinash R.

    1999-12-01

    The Atmospheric Infrared Sounder (AIRS) has been developed for the NASA Earth Observing System (EOS) program for a scheduled launch on the EOS PM-1 spacecraft in December 2000. AIRS, working in concert with complementary microwave instrumentation on EOS PM-1 is designed to provide both new and more accurate data about the atmosphere, land and oceans for application to NASA climate studies and NOAA and DOD weather prediction. Among the important parameters to be derived from AIRS observations are atmospheric temperature profiles with an average accuracy of 1 K in 1 kilometer (km) layers in the troposphere, humidity profiles to 10% accuracy and surface temperatures with an average accuracy of 0.5 K. The AIRS measurement technique is based on passive IR remote sensing using a precisely calibrated, high spectral resolution grating spectrometer operating in the 3.7 - 15.4 micrometer region. The instrument concept uses a passively cooled multi- aperture echelle array spectrometer approach in combination with advanced state of the art focal plane and cryogenic refrigerator technology to achieve unparalleled performance capability in a practical long life configuration. The AIRS instrument, which has been under development since 1991, has been fully integrated and has completed successfully a comprehensive performance verification program. Performance verification included thermal vacuum testing, environmental qualification and a full range of spatial, spectral and radiometric calibrations, which have demonstrated outstanding spectrometric performance. This paper provides a brief overview of the AIRS mission and instrument design along with key results from the test program.

  14. The Atmospheric Infrared Sounder Version 6 Cloud Products

    NASA Technical Reports Server (NTRS)

    Kahn, B. H.; Irion, F. W.; Dang, V. T.; Manning, E. M.; Nasiri, S. L.; Naud, C. M.; Blaisdell, J. M.; Schreier, M. M..; Yue, Q.; Bowman, K. W.; Fetzer, E. J.; Hulley, G. C.; Liou, K. N.; Lubin, D.; Ou, S. C.; Susskind, J.; Takano, Y.; Tian, B.; Worden, J. R.

    2014-01-01

    The version 6 cloud products of the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU) instrument suite are described. The cloud top temperature, pressure, and height and effective cloud fraction are now reported at the AIRS field-of-view (FOV) resolution. Significant improvements in cloud height assignment over version 5 are shown with FOV-scale comparisons to cloud vertical structure observed by the CloudSat 94 GHz radar and the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP). Cloud thermodynamic phase (ice, liquid, and unknown phase), ice cloud effective diameter D(sub e), and ice cloud optical thickness (t) are derived using an optimal estimation methodology for AIRS FOVs, and global distributions for 2007 are presented. The largest values of tau are found in the storm tracks and near convection in the tropics, while D(sub e) is largest on the equatorial side of the midlatitude storm tracks in both hemispheres, and lowest in tropical thin cirrus and the winter polar atmosphere. Over the Maritime Continent the diurnal variability of tau is significantly larger than for the total cloud fraction, ice cloud frequency, and D(sub e), and is anchored to the island archipelago morphology. Important differences are described between northern and southern hemispheric midlatitude cyclones using storm center composites. The infrared-based cloud retrievals of AIRS provide unique, decadal-scale and global observations of clouds over portions of the diurnal and annual cycles, and capture variability within the mesoscale and synoptic scales at all latitudes.

  15. Middle Atmosphere Sounder and Thermal Emission Radiometer - Master

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.; Scott, D. K.; Esplin, R. W.; Bailey, S. M.; Randall, C. E.

    2014-12-01

    The Middle Atmosphere Sounder and Thermal Emission Radiometer (MASTER) instrument is an advanced infrared limb-scanning instrument designed to measure the thermal structure, chemical composition, and energy balance from the stratosphere to the lower thermosphere. MASTER builds on NASA's long and successful heritage of infrared limb scanners including the LIMS, HIRDLS, and SABER instruments. MASTER has exceptional radiometric sensitivity with a more efficient, compact, and lightweight design. An updated focal plane enables critical new science in the areas of the carbon budget closure, geomagnetically-driven ozone destruction, and auroral energy deposition, while virtually eliminating out of band contributions via dual filtering. MASTER will continue the SABER-TIMED and EOS-Aura records of temperature, lower stratospheric water vapor, ozone, methane, and thermospheric cooling by nitric oxide and carbon dioxide. MASTER's size and mass are specifically designed to allow flexibility in the choice of small satellite buses and low cost launch vehicles. The expanded focal plane enables a choice of channels applicable to science objectives in NASA's Earth Science and Heliophysics enterprises. Due to the long and successful heritage the MASTER instrument is at an exceptionally high technology readiness level. No new technologies are required to build the MASTER flight instrument.

  16. 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

  17. Cross-track infrared sounder FPAA performance

    NASA Astrophysics Data System (ADS)

    Masterjohn, Stacy A.; D'Souza, Arvind I.; Dawson, Larry C.; Dolan, Peter N.; Jefferson, Genae; Stapelbroek, Maryn G.; Willis, Richard W.; Wijewarnasuriya, Priyalal S.; Boehmer, Ellen; Ehlert, John C.; Andrews, James E.

    2005-01-01

    The Cross-track Infrared Sounder (CrIS), an interferometric sounder, is one of the instruments within the National Polar-orbiting Operational Environmental Satellite System (NPOESS) suite. CrIS measures earth radiances at high spectral resolution providing accurate and high-resolution pressure, temperature and moisture profiles of the atmosphere. These profiles are used in weather prediction models to track storms, predict levels of precipitation etc. Each CrIS instrument contains three Focal Plane Array Assemblies (FPAAs): SWIR [λc(98 K) ~ 5 mm], MWIR [λc(98 K) ~ 9 mm], and LWIR [λc(81 K) ~ 16 mm]. Each FPAA consists of nine large (850-mm-diameter) photovoltaic detectors arranged in a 3 x 3 pattern, with each detector having an accompanying cold preamplifier. This paper describes the selection methodology of the detectors that constitute the FPAAs and the performance of the CrIS SWIR, MWIR and LWIR proto-flight FPAAs. The appropriate bandgap n-type Hg1-xCdxTe was grown on lattice-matched CdZnTe. 850-mm-diameter photodiodes were manufactured using a Lateral Collection Diode (LCD) architecture. Custom pre-amplifiers were designed and built to interface with these large photodiodes. The LWIR, MWIR and SWIR detectors are operated at 81 K, 98 K and 98 K respectively. These relatively high operating temperatures permit the use of passive radiators on the instrument to cool the detectors. Performance goals are D* = 5.0 x 1010 cm-Hz1/2/W at 14.0 mm, 9.3 x 1010 cm-Hz1/2/W at 8.0 mm and 3.0 x 1011 cm-Hz1/2/W at 4.64 mm. Measured mean values for the nine photodiodes in each of the LWIR, MWIR and SWIR FPAAs are D* = 5.3 x 1010 cm-Hz1/2/W at 14.0 mm, 1.0 x 1011 cm-Hz1/2/W at 8.0 mm and 3.1 x 1011 cm-Hz1/2/W at 4.64 mm. These compare favorably with the following BLIP D* values calculated at the nominal flux condition: D* = 8.36 x 1010 cm Hz1/2/W at 14.0 mm, 1.4 x 1011 cm-Hz1/2/W at 8.0 mm and 4.1 x 1011 cm-Hz1/2/W at 4.64 mm.

  18. 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.

  19. Ionospheric modelling for navigation

    NASA Astrophysics Data System (ADS)

    Aragon Angel, M. A.

    Signals transmitted to and from satellites for communication and navigation purposes must pass through the ionosphere Ionospheric irregularities most common at equatorial latitudes although they could occur anywhere can have a major impact on system performance and reliability and commercial navigation service satellite-based providers need to account for their effects For a GNSS single-frequency receiver the Slant Total Electron Content STEC must be known by the user through broadcast corrections In this context there are several sets of broadcast parameters that can be defined to take into account this ionospheric term The chosen model to generate the ionospheric correction coefficients for the present study is the NeQuick model although with a number of adaptations intended to improve effective ionospheric effect modelling performances The aim of this study is to describe a possible adaptation to the NeQuick model for real time purposes and suitable for single frequency users Therefore it will be necessary to determine the performance of this modified NeQuick model in correcting the ionospheric delay In order to generate the ionospheric corrections for single frequency receivers using the NeQuick model a certain approach should be followed to adapt the performance of NeQuick since this model was originally developed to provide TEC using averaged monthly information of the solar activity and not daily one Thus to use NeQuick for real time applications as an ionospheric broadcasted model such as Klobuchar solar daily information at the user point

  20. Work of PZT ceramics sounder for sound source artificial larynx

    NASA Astrophysics Data System (ADS)

    Sugio, Yuuichi; Kanetake, Ryota; Tanaka, Akimitsu; Ooe, Katsutoshi

    2007-04-01

    We aim to develop the easy-to-use artificial larynx with high tone quality. We focus on using a PZT ceramics sounder as its sound source, because it is small size, low power consumption, and harmless to humans. But conventional PZT ceramics sounder have the problem that it cannot generate an enough sound in the low frequency range, thus they cannot be used for artificial larynx. Then, we aim to develop the PZT ceramics sounder which can generate enough volume in the low frequency range. If we can lower the resonance frequency of the sounder, it can generate low pitch sound easily. Therefore I created the new diaphragm with low resonance frequency. In addition, we could obtain the high amplitude by changing method of driving. This time, we report on the characteristic comparison of this new PZT ceramics sounder and conventional one. Furthermore, for this new one, we analyzed the best alignment of PZT ceramics and the shape of the diaphragm to obtain low resonance frequency and big amplitude. In fact we analyzed the optimization of the structure. The analysis is done by computer simulation of ANSYS and Laser Doppler Vibrometer. In the future, we will add intonation to the generated sound by input wave form which is developed concurrently, and implant the sounder inside of the body by the method of fixing metal to biomolecule which is done too. And so high tone quality and convenient artificial larynx will be completed.

  1. The geologic setting of the Mars north polar cap's Basal Unit from the three dimensional analysis of MARSIS planetary radar sounder data

    NASA Astrophysics Data System (ADS)

    Frigeri, A.; Orosei, R.; Cartacci, M.; Cicchetti, A.; Giuppi, S.; Noschese, R.; Plaut, J.

    2012-12-01

    Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) is the orbital subsurface sounder aboard ESA's Mars Express spacecraft. It transmits a low-frequency radar pulse capable of penetrating below the surface, where subsurface dielectric discontinuities originate secondary echoes. MARSIS has been used to probe both the south and the north polar caps of Mars, revealing their thickness and structure. We report on the results of a campaign of observations of the north polar ice cap of Mars that took place between May and December 2011 in uniquely favorable conditions, and produced data of unprecedented quality. The focus of our work is the detection of signals from the Basal Unit, the dark, ice-rich, complexely layered geologic unit lying stratigraphically between the polar layered deposits and the Vastitas Borealis Formation, and extending beneath most of Planum Boreum and Olympia Planitia. The objective of this work is the study of the full three dimensional structure of the Northern Polar Deposit and in particular of the Basal Unit (BU). The analysis of signals in bi-dimensional radargrams sounding the BU reveal a layering of the unit, probably correlated with the Rupes Tenuis - Planum Boreum Cavi units' boundary. Using the density of data available from the 2011 polar campaign, we assembled radar observations into a three dimensional volume of data. The use of visualization techniques allow to explore these data interactively, identifying patterns that can be problematic to detect with unsupervised automatic methods. This way, specific areas, or sub-volumes, are being selected to be studied in detail. We will present MARSIS data from the Mars North Polar campaign, as well as the preliminary interpretation of these data in three dimensions, and the possible implications for the geologic history of the northern Martian ice-cap.

  2. Electrodynamics and plasma processes in the ionosphere

    NASA Technical Reports Server (NTRS)

    Heelis, R. A.

    1987-01-01

    The paper examines the advances achieved between 1983 and 1986 on understanding ionospheric electrodynamics and associated plasma processes, including an assessment of the roles of the E- and F-region neutral winds in providing the large-scale electric field in the ionosphere, as well as of the influence of electric fields of magnetospheric origin on the motion and distribution of plasma. Studies of the factors affecting the creation and evolution of plasma structure with many different scale sizes are discussed. Consideration is also given to the ground-based and in situ techniques used in these studies.

  3. GRIPS - The Geostationary Remote Infrared Pollution Sounder

    NASA Astrophysics Data System (ADS)

    Spackman, Ryan; Dickerson, Russell; Schoeberl, Mark; Bloom, Hal; Gordley, Larry; McHugh, Martin; Thompson, Anne; Burrows, John; Zeng, Ning; Marshall, Tom; Fish, Chad; Kim, Jhoon; Park, Rokjin; Warner, Juying; Bhartia, Pawan; Kollonige, Debra

    2013-04-01

    Climate change and air quality are the most pressing environmental issues of the 21st century for America and for the world as a whole. Despite decades of research, the sources and sinks of key greenhouse gases and other pollutants remain highly uncertain making atmospheric composition predictions difficult. The Geostationary Remote Infrared Pollution Sounder (GRIPS) will measure carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4). By using measurements of nitrous oxide (N2O) and the O2 A-band to help correct for clouds and aerosols, GRIPS will achieve unprecedented precision. Together these gases account for about 85% of all climate forcing and they impact atmospheric ozone (O3). GRIPS, employing gas-filter correlation radiometry, uses the target gases themselves in place of dispersive elements to achieve outstanding throughput, sensitivity, and specificity. Because it uses a combination of reflected and thermal IR, GRIPS will detect trace gas concentrations right down to the Earth's surface. When flown in parallel to a UV/VIS sensor such as GEMS on GEO-KOMPSAT-2B over East Asia or the Sentinel 4 on MTG over Europe/Africa, the combination offers powerful finger-printing capabilities to distinguish and quantify diverse pollution sources such as electricity generation, biomass burning, and motor vehicles. From geostationary orbit, GRIPS will be able to focus on important targets to quantify sources, net flux, diurnal cycles, and long-range transport of these key components in the Earth's radiative balance and air quality.

  4. GRIPS - The Geostationary Remote Infrared Pollution Sounder

    NASA Astrophysics Data System (ADS)

    Dickerson, R. R.; Schoeberl, M. R.; Gordley, L. L.; McHugh, M. J.; Thompson, A. M.; Burrows, J. P.; Zeng, N.; Marshall, B. T.; Fish, C. S.; Spackman, J. R.; Kim, J.; Park, R.; Warner, J. X.; Bhartia, P. K.; Kollonige, D. E.

    2012-12-01

    Climate change and air quality are the most pressing environmental issues of the 21st century - for America and for the world as a whole. Despite decades of research, the sources and sinks of key greenhouse gases and other pollutants remain highly uncertain making atmospheric composition predictions difficult. The Geostationary Remote Infrared Pollution Sounder (GRIPS) will measure carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4). By using measurements of nitrous oxide (N2O) and the O2 A-band to help correct for clouds and aerosols, GRIPS will achieve unprecedented precision. Together these gases account for about 85% of all climate forcing and they impact atmospheric ozone (O3). GRIPS, employing gas-filter correlation radiometry, uses the target gases themselves in place of dispersive elements to achieve outstanding throughput, sensitivity, and specificity. Because it uses a combination of reflected and thermal IR, GRIPS will detect trace gas concentrations right down to the Earth's surface. When flown in parallel to a UV/VIS sensor such as GEMS on GEO-KOMPSAT-2B over East Asia or the Sentinel 4 on MTG over Europe/Africa, the combination offers powerful finger-printing capabilities to distinguish and quantify diverse pollution sources such as electricity generation, biomass burning, and motor vehicles. From geostationary orbit, GRIPS will be able to focus on important targets to quantify sources, net flux, diurnal cycles, and long-range transport of these key components in the Earth's radiative balance and air quality.

  5. Planetary protection for Europa radar sounder antenna

    NASA Astrophysics Data System (ADS)

    Aaron, Kim M.; Moussessian, Alina; Newlin, Laura E.; Willis, Paul B.; Chen, Fei; Harcke, Leif J.; Chapin, Elaine; Jun, Insoo; Gim, Yonggyu; McEachen, Michael; Allen, Scotty; Kirchner, Donald; Blankenship, Donald

    2016-05-01

    The potential for habitability puts stringent requirements on planetary protection for a mission to Europa. A long-wavelength radar sounder with a large antenna is one of the proposed instruments for a future Europa mission. The size and construction of radar sounding antennas make the usual methods of meeting planetary protection requirements challenging. This paper discusses a viable planetary protection scheme for an antenna optimized for Europa radar sounding. The preferred methodology for this antenna is exposure to 100 kGy (10 Mrad) in water of gamma radiation using a Cobalt-60 source for both bulk and surface sterilization and exposure to vapor hydrogen peroxide for surface treatment for possible recontamination due to subsequent handling. For the boom-supported antenna design, selected tests were performed to confirm the suitability of these treatment methods. A portion of a coilable boom residual from an earlier mission was irradiated and its deployment repeatability confirmed with no degradation. Elasticity was measured of several fiberglass samples using a four-point bending test to confirm that there was no degradation due to radiation exposure. Vapor hydrogen peroxide treatment was applied to the silver-coated braid used as the antenna radiating element as it was the material most likely to be susceptible to oxidative attack under the treatment conditions. There was no discernable effect. These tests confirm that the radar sounding antenna for a Europa mission should be able tolerate the proposed sterilization methods.

  6. Pioneer Venus Sounder Probe Solar Flux Radiometer

    NASA Technical Reports Server (NTRS)

    Tomasko, M. G.; Doose, L. R.; Palmer, J. M.; Holmes, A.; Wolfe, W. L.; Debell, A. G.; Brod, L. G.; Sholes, R. R.

    1980-01-01

    The Solar Flux Radiometer aboard the Pioneer Venus Sounder Probe operated successfully during its descent through the atmosphere of Venus. The instrument measured atmospheric radiance over the spectral range from 400 to 1800 nm as a function of altitude. Elevation and azimuthal measurements on the radiation field were made with five optical channels. Twelve filtered Si and Ge photovoltaic detectors were maintained near 30 C with a phase-change material. The detector output currents were processed with logarithmic transimpedance converters and digitized with an 11-bit A/D converter. Atmospheric sampling in both elevation and azimuth was done according to a Gaussian integration scheme. The serial output data averaged 20 bits/sec, including housekeeping (sync, spin period, sample timing and mode). The data were used to determine the deposition of solar energy in the atmosphere of Venus between 67 km and the surface along with upward and downward fluxes and radiances with an altitude resolution of several hundred meters. The results allow for more accurate modeling of the radiation balance of the atmosphere than previously possible.

  7. Remote detection of the maximum altitude of equatorial ionospheric plasma bubbles

    NASA Technical Reports Server (NTRS)

    Benson, R. F.

    1981-01-01

    Nearly 200 post-sunset low-altitude passes of the Alouette 2 and ISIS 1 satellites near the dip equator are studied in order to find the maximum ionospheric plasma bubble altitudes, which are determined by calculating the apex altitude of the magnetic field line passing through the satellite when it is immersed in a bubble. The calculations are made only upon the observation of conjugate hemisphere ionospheric echoes, which result from ducted HF sounder signals that are guided along field-aligned irregularities within the plasma depletion. The maximum bubble altitudes corresponding to the three longitude sectors centered on zero deg, 75 deg W, and 105 deg E, are found to often exceed 1000 km, but seldom 3000 km. The electron density depletions within these field-aligned bubbles, as measured at the point of satellite encounter with the topside ionosphere, are generally less than a factor of two but may exceed a factor of ten.

  8. 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.

  9. Enhanced ionization of the Martian nightside ionosphere during solar energetic particle events

    NASA Astrophysics Data System (ADS)

    Nemec, F.; Morgan, D. D.; Dieval, C.; Gurnett, D. A.; Futaana, Y.

    2013-12-01

    The nightside ionosphere of Mars is highly variable and very irregular, controlled to a great extent by the configuration of the crustal magnetic fields. The ionospheric reflections observed by the MARSIS radar sounder on board the Mars Express spacecraft in this region are typically oblique (reflection by a distant feature), so that they cannot be used to determine the peak altitude precisely. Nevertheless, the peak electron density can be in principle readily determined. However, in more than 90% of measurements the peak electron densities are too low to be detected. We focus on the time intervals of solar energetic particle (SEP) events. One may expect high energy particle precipitation into the nightside ionosphere to increase the electron density there. Thus, comparison of characteristics between SEP/no-SEP time intervals is important to understand the formation mechanism of the nightside ionosphere. The time intervals of SEP events are determined using the increase in the background counts recorded by the ion sensor (IMA) of the ASPERA-3 particle instrument on board Mars Express. Then we use MARSIS measurements to determine how much the nightside ionosphere is enhanced during these time intervals. We show that the peak electron densities during these periods are large enough to be detected in more than 30% of measurements, while the reflections from the ground almost entirely disappear, indicating that the nightside electron densities are tremendously increased as compared to the normal nightside conditions. The influence of various parameters on the formation of the nightside ionosphere is thoroughly discussed.

  10. Extremely Low Ionospheric Peak Altitudes in the Polar-Hole Region

    NASA Technical Reports Server (NTRS)

    Benson, Robert F.; Grebowsky, Joseph M.

    1999-01-01

    Vertical electron-density (N (sub e)) profiles, deduced from newly-available ISIS-II digital ionospheric topside-sounder data, are used to investigate the "polar-hole" region within the winter, nighttime polar cap ionosphere during solar minimum. The hole region is located around 0200 MLT near the poleward side of the auroral oval. Earlier investigations had revealed very low N (sub e) values in this region (down to 200/cu cm near 300 km). In the present study, such low N, values (approx. 100/cu cm) were only found near the ISIS (International Satellite for Ionospheric Study)-II altitude of 1400 km. The peak ionospheric concentration below the spacecraft remained fairly constant (approx. 10 (exp 5)/cu cm across the hole region but the altitude of the peak dropped dramatically. This peak dropped, surprisingly, to the vicinity of 100 km. These observations suggest that the earlier satellite in situ measurements, interpreted as deep holes in the ionospheric F-region concentration, could have been made during conditions of an extreme decrease in the altitude of the ionospheric N (sub e) peak. The observations, in combination with other data, indicate that the absence of an F-layer peak may be a frequent occurrence at high latitudes.

  11. 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.

  12. Cross-track infrared sounder FPAA performance

    NASA Astrophysics Data System (ADS)

    Masterjohn, Stacy A.; D'Souza, Arvind I.; Dawson, Larry C.; Dolan, Peter N.; Wijewarnasuriya, Priyalal S.; Ehlert, John C.

    2003-01-01

    ABSTRACT The Cross-track Infrared Sounder (CrIS) is one of many instruments that comprise the National Polar-orbiting Operational Environmental Satellite System (NPOESS). The CrIS instrument is a Michelson interferometer-based sensor that is sensitive to wavelengths between 3.5 and 16 microns. Three separate Focal Plane Array Assemblies (FPAAs) referred to as the Short Wave Infrared Assembly, the Mid Wave Infrared assembly, and the Long Wave Infrared assembly are used to span the spectral range. The CrIS instrument measures the earth radiance at high spectral resolution using the data to provide pressure, temperature and moisture profiles of the atmosphere. The CrIS instrument will help improve both global and regional predictions of weather patterns, storm tracks, and precipitation. The CrIS program selected photovoltaic (PV) detectors for use in all three spectral bands. PV technology outperforms photoconductive detectors in terms of high sensitivity and linearity. Each FPAA consists of a 3×3 detector-matrix that are used to form 9 fields of view (FOV). Each detector has a 1,000 mm active area diameter and has its own cold preamplifier, warm post amplifier and independent high pass filter. This paper describes the performance for all three assemblies that together form the basis of the CrIS Engineering Development Unit 2 (EDU2) Detector Preamp Module (DPM). Molecular Beam Epitaxy (MBE) is used to grow the appropriate bandgap n-type Hg1-xCdxTe on lattice matched CdZnTe. SWIR, MWIR and LWIR 1000 mm diameter detectors have been manufactured using the Lateral Collection Diode (LCD) architecture. Custom pre-amplifiers have been designed to interface with the large SWIR, MWIR and LWIR detectors. The operating temperature is above 78 K, permitting the use of passive radiators in spacecraft to cool the detectors. Recently, all three FPAAs were completed and tested. The tests performed on each assembly are listed.

  13. The Exomars Climate Sounder (EMCS) Investigation

    NASA Astrophysics Data System (ADS)

    Forget, F.; Schofield, J. T.; Kass, D. M.; Kleinböhl, A.; McCleese, D. J.; Allen, M. A.; Foote, M. C.; Millour, E.; Spiga, A.; Talagrand, O.; Calcutt, S. B.; Irwin, P. G. J.; Read, P. L.; Lewis, S. R.; Fouchet, T.; Lefèvre, F.; Määttänen, A.; Barnes, J. R.; Bougher, S. W.; Haberle, R. M.; Jeganathan, M.; Bowles, N.

    2011-10-01

    The ExoMars Climate Sounder (EMCS) investigation is developed at the Jet Propulsion Laboratory (Principal Investigator J. T. Schofield) in collaboration with an international scientific team from France, the United Kingdom and the USA. EMCS plans to map daily, global, pole-to-pole profiles of temperature, dust, water and CO2 ices, and water vapor from the proposed 2016 ExoMars Trace Gas Orbiter (EMTGO). These profiles are to be assimilated into Mars General Circulation Models (MGCMs) to generate global, interpolated fields of measured and derived parameters such as wind. Sciences objectives of EMCS are to: Enhance understanding of Mars photochemistry by providing daily, global, high vertical resolution fields of atmospheric state, aerosol distribution, and water vapor concentration. EMCS atmospheric state measurements, combined with data assimilation, characterize the transport, sources and sinks of trace gases measured by the proposed EMTGO. The aerosol measurements reveal the heterogeneous photochemical pathways of trace gases. EMCS plans to map water vapor, the key source gas for odd hydrogen, known to be important in Martian photochemistry. Extend the MRO/MCS climatology of high vertical resolution measurements of the lower and middle atmosphere of Mars, with the improved coverage of local time provided by the proposed EMTGO. EMCS will determine the diurnal, seasonal & long-term variability of temperature and aerosol, and its impact on photochemistry. EMCS climatology, combined with earlier data, would relate EMTGO observations to earlier trace gas measurements. Support future Mars missions with measured climatology and near real-time density profile retrievals for landing and aerocapture, in the same way that MRO/MCS supported the Phoenix landing and is supporting the Mars Science Laboratory (MSL) landing. EMCS could be the only instrument in orbit able to support Entry, Descent and Landing (EDL) for the proposed ExoMars 2018 Rover Mission.

  14. Latest developments of geostationary microwave sounder technologies for NOAA's mission

    NASA Astrophysics Data System (ADS)

    Bajpai, Shyam; Madden, Michael; Chu, Donald; Yapur, Martin

    2006-12-01

    The National Oceanic and Atmospheric Administration (NOAA) have been flying microwave sounders since 1975 on Polar Operational Environmental Satellites (POES). Microwave observations have made significant contributions to the understanding of the atmosphere and earth surface. This has helped in improving weather and storm tracking forecasts. However, NOAA's Geostationary Operational Environmental Satellites (GOES) have microwave requirements that can not be met due to the unavailability of proven technologies. Several studies of a Geostationary Microwave Sounder (GMS) have been conducted. Among those, are the Geostationary Microwave Sounder (GEM) that uses a mechanically steered solid dish antenna and the Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) that utilizes a sparse aperture array. Both designs take advantage of the latest developments in sensor technology. NASA/Jet Propulsion Lab (JPL) has recently successfully built and tested a prototype ground-based GeoSTAR at 50 GHz frequency with promising test results. Current GOES IR Sounders are limited to cloud top observations. Therefore, a sounding suite of IR and Microwave should be able to provide observations under clear as well as cloudy conditions all the time. This paper presents the results of the Geostationary Microwave Sounder studies, user requirements, frequencies, technologies, limitations, and implementation strategies.

  15. Radar Ionospheric Impact Mitigation

    NASA Astrophysics Data System (ADS)

    Bishop, G.; Decker, D.; Baker, C.

    2006-12-01

    New ionospheric modeling technology is being developed to improve correction of ionospheric impacts on the performance of ground-based space-surveillance radars (SSRs) in near-real-time. These radars, which detect and track space objects, can experience significant target location errors due to ionospheric delay and refraction of the radar signals. Since these radars must detect and track targets essentially to the radar horizon, it is necessary to accurately model the ionosphere as the radar would observe it, down to the local horizon. To correct for spatial and temporal changes in the ionosphere the model must be able to update in near-real-time using ionospheric sensor data. Since many radars are in isolated locations, or may have requirements to operate autonomously, an additional required capability is to provide accurate ionospheric mitigation by exploiting only sensor data from the radar site. However, the model must also be able to update using additional data from other types of sensors that may be available. The original radar ionospheric mitigation approach employed the Bent climatological model. This 35-year-old technology is still the means employed in the many DoD SSRs today. One more recent approach used capabilities from the PRISM model. PRISM technology has today been surpassed by `assimilative models' which employ better physics and Kalman filtering techniques. These models are not necessarily tailored for SSR application which needs to optimize modeling of very small regions using only data from a single sensor, or very few. The goal is to develop and validate the performance of innovative and efficient ionospheric modeling approaches that are optimized for the small regions applicable to ground-based radar coverage (radius of ~2000 km at ionospheric altitudes) and somewhat beyond. These approaches must adapt a continuous modeling scheme in near-real-time to be consistent with all observational data that may become available, and degrade

  16. 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.

  17. Global Ionosphere Radio Observatory

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    The Global Ionosphere Radio Observatory (GIRO) comprises a network of ground-based high-frequency vertical sounding sensors, ionosondes, with instrument installations in 27 countries and a central Lowell GIRO Data Center (LGDC) for data acquisition and assimilation, including 46 real-time data streams as of August 2014. The LGDC implemented a suite of technologies for post-processing, modeling, analysis, and dissemination of the acquired and derived data products, including: (1) IRI-based Real-time Assimilative Model, "IRTAM", that 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; (2) Global Assimilative Model of Bottomside Ionosphere Timelines (GAMBIT) Database and Explorer holding 15 years worth of IRTAM computed maps at 15 minute cadence;. (3) 17+ million ionograms and matching ionogram-derived records of URSI-standard ionospheric characteristics and vertical profiles of electron density; (4) 10+ million records of the Doppler Skymaps showing spatial distributions over the GIRO locations and plasma drifts; (5) Data and software for Traveling Ionospheric Disturbance (TID) diagnostics; and (6) HR2006 ray tracing software mated to the "realistic" IRTAM ionosphere. In cooperation with the URSI Ionosonde Network Advisory Group (INAG), the LGDC promotes cooperative agreements with the ionosonde observatories of the world to accept and process real-time data of HF radio monitoring of the ionosphere, and to promote a variety of investigations that benefit from the global-scale, prompt, detailed, and accurate descriptions of the ionospheric variability.

  18. 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

  19. 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

  20. Study of stratospheric-ionospheric coupling during thunderstorms and tornadoes

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Smith, R. E.

    1977-01-01

    A continuous-wave-spectrum high-frequency Doppler sounder array with three transmitters at each of three sites was used to observe the dynamics of the coupling of energy between the stratosphere and the ionosphere. During times of severe weather activity wavelike disturbances have been detected on ground-based ionospheric sounding records as perturbations in electron densities. Infrasonic waves with wave periods of 3-7 min and with horizontal phase velocities of 600-800 m/s were observed when there was thunderstorm activity; gravity waves with wave periods of 10-15 min and horizontal phase velocities of 100-200 m/s were detected when there was tornado activity. Both triangulations from the cross correlation functions of the Doppler records based on an assumption of no background wind shear and ray-tracing computations including an assumed background wind shear indicate that the waves originated in the vicinity of the thunderstorms and tornadoes. A comparison of the wavelengths of the infrasonic and gravity waves observed at ionospheric heights and those in cloud-top pictures from satellites show that they are all of the order of 100-300 km.

  1. Note on the Effect of Horizontal Gradients for Nadir-Viewing Microwave and Infrared Sounders

    NASA Technical Reports Server (NTRS)

    Joiner, J.; Poli, P.

    2004-01-01

    Passive microwave and infrared nadir sounders such as the Advanced Microwave Sounding Unit A (AMSU-A) and the Atmospheric InfraRed Sounder (AIRS), both flying on NASA s EOS Aqua satellite, provide information about vertical temperature and humidity structure that is used in data assimilation systems for numerical weather prediction and climate applications. These instruments scan cross track so that at the satellite swath edges, the satellite zenith angles can reach approx. 60 deg. The emission path through the atmosphere as observed by the satellite is therefore slanted with respect to the satellite footprint s zenith. Although radiative transfer codes currently in use at operational centers use the appropriate satellite zenith angle to compute brightness temperature, the input atmospheric fields are those from the vertical profile above the center of the satellite footprint. If horizontal gradients are present in the atmospheric fields, the use of a vertical atmospheric profile may produce an error. This note attempts to quantify the effects of horizontal gradients on AIRS and AMSU-A channels by computing brightness temperatures with accurate slanted atmospheric profiles. We use slanted temperature, water vapor, and ozone fields from data assimilation systems. We compare the calculated slanted and vertical brightness temperatures with AIRS and AMSU-A observations. We show that the effects of horizontal gradients on these sounders are generally small and below instrument noise. However, there are cases where the effects are greater than the instrument noise and may produce erroneous increments in an assimilation system. The majority of the affected channels have weighting functions that peak in the upper troposphere (water vapor sensitive channels) and above (temperature sensitive channels) and are unlikely t o significantly impact tropospheric numerical weather prediction. However, the errors could be significant for other applications such as stratospheric

  2. View to the eastnortheast of the Sounder Antenna OvertheHorizon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View to the east-northeast of the Sounder Antenna - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Five Sounder Antennas, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  3. View to the northeast of the Sounder Antenna OvertheHorizon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View to the northeast of the Sounder Antenna - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Five Sounder Antennas, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  4. 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

  5. Electron Density Profiles of the Topside Ionosphere

    NASA Technical Reports Server (NTRS)

    Huang, Xue-Qin; Reinsch, Bodo W.; Bilitza, Dieter; Benson, Robert F.

    2002-01-01

    The existing uncertainties about the electron density profiles in the topside ionosphere, i.e., in the height region from h,F2 to - 2000 km, require the search for new data sources. The ISIS and Alouette topside sounder satellites from the sixties to the eighties recorded millions of ionograms but most were not analyzed in terms of electron density profiles. In recent years an effort started to digitize the analog recordings to prepare the ionograms for computerized analysis. As of November 2001 about 350000 ionograms have been digitized from the original 7-track analog tapes. These data are available in binary and CDF format from the anonymous ftp site of the National Space Science Data Center. A search site and browse capabilities on CDAWeb assist the scientific usage of these data. All information and access links can be found at http://nssdc.gsfc.nasa.gov/space/isis/isis- status.htm1. This paper describes the ISIS data restoration effort and shows how the digital ionograms are automatically processed into electron density profiles from satellite orbit altitude (1400 km for ISIS-2) down to the F peak. Because of the large volume of data an automated processing algorithm is imperative. The TOPside Ionogram Scaler with True height algorithm TOPIST software developed for this task is successfully scaling - 70% of the ionograms. An <> is available to manually scale the more difficult ionograms. The automated processing of the digitized ISIS ionograms is now underway, producing a much-needed database of topside electron density profiles for ionospheric modeling covering more than one solar cycle.

  6. Sensor System Performance Evaluation and Benefits from the NPOESS Airborne Sounder Testbed-Interferometer (NAST-I)

    NASA Technical Reports Server (NTRS)

    Larar, A.; Zhou, D.; Smith, W.

    2009-01-01

    Advanced satellite sensors are tasked with improving global-scale measurements of the Earth's atmosphere, clouds, and surface to enable enhancements in weather prediction, climate monitoring, and environmental change detection. Validation of the entire measurement system is crucial to achieving this goal and thus maximizing research and operational utility of resultant data. Field campaigns employing satellite under-flights with well-calibrated FTS sensors aboard high-altitude aircraft are an essential part of this validation task. The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed-Interferometer (NAST-I) has been a fundamental contributor in this area by providing coincident high spectral/spatial resolution observations of infrared spectral radiances along with independently-retrieved geophysical products for comparison with like products from satellite sensors being validated. This paper focuses on some of the challenges associated with validating advanced atmospheric sounders and the benefits obtained from employing airborne interferometers such as the NAST-I. Select results from underflights of the Aqua Atmospheric InfraRed Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) obtained during recent field campaigns will be presented.

  7. Suomi NPP/JPSS Cross-track Infrared Sounder (CrIS): Calibration Validation With The Aircraft Based Scanning High-resolution Interferometer Sounder (S-HIS)

    NASA Astrophysics Data System (ADS)

    Taylor, J. K.; Revercomb, H. E.; Tobin, D.; Knuteson, R. O.; Best, F. A.; Adler, D. A.; Pettersen, C.; Garcia, R. K.; Gero, P.

    2013-12-01

    To better accommodate climate change monitoring and improved weather forecasting, there is an established need for higher accuracy and more refined error characterization of radiance measurements from space and the corresponding geophysical products. This need has led to emphasizing direct tests of on-orbit performance, referred to as validation. Currently, validation typically involves (1) collecting high quality reference data from airborne and/or ground-based instruments during the satellite overpass, and (2) a detailed comparison between the satellite-based radiance measurements and the corresponding high quality reference data. Additionally, for future missions technology advancements at the University of Wisconsin Space Science and Engineering Center (UW-SSEC) have led to the development of an on-orbit absolute radiance reference utilizing miniature phase change cells to provide direct on-orbit traceability to International Standards (SI). The detailed comparison between the satellite-based radiance measurements and the corresponding measurements made from a high-altitude aircraft must account for instrument noise and scene variations, as well as differences in instrument observation altitudes, view angles, spatial footprints, and spectral response. Most importantly, for the calibration validation process to be both accurate and repeatable the reference data instrument must be extremely well characterized and understood, carefully maintained, and accurately calibrated, with traceability to absolute standards. The Scanning High-resolution Interferometer Sounder (S-HIS) meets and exceeds these requirements and has proven to do so on multiple airborne platforms, each with significantly different instrument operating environments. The Cross-track Infrared Sounder (CrIS) on Suomi NPP, launched 28 October 2011, is designed to give scientists more refined information about Earth's atmosphere and improve weather forecasts and our understanding of climate. CrIS is an

  8. Robust detection of ionospheric irregularities

    NASA Technical Reports Server (NTRS)

    Walter, T.; Hansen, A.; Blanch, J.; Enge, P.; Mannucci, T.; Pi, X.; Sparks, L.; Iijima, B.; El-Arini, B.; Lejeune, R.; Hagen, M.; Altshuler, E.; Fries, R.; Chu, A.

    2000-01-01

    The approach outlined in this paper conservatively bounds the ionospheric errors even for the worst observed ionospheric conditions to date, using data sets taken from the operational receivers in the WAAS reference station network.

  9. A Campaign to Study Equatorial Ionospheric Phenomena over Guam

    NASA Astrophysics Data System (ADS)

    Habash Krause, L.; Balthazor, R.; Dearborn, M.; Enloe, L.; Lawrence, T.; McHarg, M.; Petrash, D.; Reinisch, B. W.; Stuart, T.

    2007-05-01

    With the development of a series of ground-based and space-based experiments, the United States Air Force Academy (USAFA) is in the process of planning a campaign to investigate the relationship between equatorial ionospheric plasma dynamics and a variety of space weather effects, including: 1) ionospheric plasma turbulence in the F region, and 2) scintillation of radio signals at low latitudes. A Digisonde Portable Sounder DPS-4 will operate from the island of Guam (with a magnetic latitude of 5.6° N) and will provide measurements of ionospheric total electron content (TEC), vertical drifts of the bulk ionospheric plasma, and electron density profiles. Additionally, a dual-frequency GPS TEC/scintillation monitor will be located along the Guam magnetic meridian at a magnetic latitude of approximately 15° N. In campaign mode, we will combine these ground-based observations with those collected from space during USAFA's FalconSAT-3 and FalconSAT-5 low-earth orbit satellite missions, the first of which is scheduled to be active over a period of several months beginning in the 2007 calendar year. The satellite experiments are designed to characterize in situ irregularities in plasma density, and include measurements of bulk ion density and temperature, minority-to- majority ion mixing ratios, small scale (10 cm to 1 m) plasma turbulence, and ion distribution spectra in energy with sufficient resolution for observations of non-thermalized distributions that may be associated with velocity- space instabilities. Specific targets of investigation include: a) a comparison of plasma turbulence observed on- orbit with spread F on ionograms as measured with the Digisonde, b) a correlation between the vertical lifting of the ionospheric layer over Guam and the onset of radio scintillation activity along the Guam meridian at 15° N magnetic latitude, and c) a correlation between on-orbit turbulence and ionospheric scintillation at 15° N magnetic latitude. These relationships

  10. Magnetosphere-ionosphere waves

    NASA Astrophysics Data System (ADS)

    Russell, A. J. B.; Wright, A. N.

    2012-01-01

    Self-consistent electrodynamic coupling of the ionosphere and magnetosphere produces waves with clearly defined properties, described here for the first time. Large scale (ideal) disturbances to the equilibrium, for which electron inertia is unimportant, move in the direction of the electric field at a characteristic speed. This may be as fast as several hundred meters per second or approximately half the E × B drift speed. In contrast, narrow scale (strongly inertial) waves are nearly stationary and oscillate at a specific frequency. Estimates of this frequency suggest periods from several tenths of a second to several minutes may be typical. Both the advection speed and frequency of oscillation are derived for a simple model and depend on a combination of ionospheric and magnetospheric parameters. Advection of large scale waves is nonlinear: troughs in E-region number density move faster than crests and this causes waves to break on their trailing edge. Wavebreaking is a very efficient mechanism for producing narrow (inertial) scale waves in the coupled system, readily accessing scales of a few hundred meters in just a few minutes. All magnetosphere-ionosphere waves are damped by recombination in the E-region, suggesting that they are to be best observed at night and in regions of low ionospheric plasma density. Links with observations, previous numerical studies and ionospheric feedback instability are discussed, and we propose key features of experiments that would test the new theory.

  11. Film handling procedures for Apollo 17 lunar sounder

    NASA Technical Reports Server (NTRS)

    Weinstein, M. S.

    1972-01-01

    Film handling procedures for the Apollo 17 Lunar Sounder are itemized, including purchase of flight film, establishment of processing standards, transportation of flight films, flight film certification, application of pre- and post-sensitometry, film loading and downloading, film processing, titling, and duplication.

  12. Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The laser atmospheric wind sounder (LAWS) will provide a new space based capability for the direct measurement of atmospheric winds in the troposphere. LAWS will make a major contribution toward advancing the understanding and prediction of the total Earth system and NASA's Earth Observing System (EOS) Program. LAWS is designed to measure a fundamental atmospheric parameter required to advance weather forecasting accuracies and investigate global climatic change. LAWS has a potential added benefit of providing (global) concentration profiles of large aerosols including visible and subvisible cirrus clouds, volcanic dust, smoke, and other pollutants. The objective of this Phase One study was to develop a LAWS concept and configuration. The instrument design is outlined in this first volume of three.

  13. Variations of the ionospheric electron density during the Bhuj seismic event

    NASA Astrophysics Data System (ADS)

    Trigunait, A.; Parrot, M.; Pulinets, S.; Li, F.

    2004-12-01

    Ionospheric perturbations by natural geophysical activity, such as volcanic eruptions and earthquakes, have been studied since the great Alaskan earthquake in 1964. Measurements made from the ground show a variation of the critical frequency of the ionosphere layers before and after the shock. In this paper, we present an experimental investigation of the electron density variations around the time of the Bhuj earthquake in Gujarat, India. Several experiments have been used to survey the ionosphere. Measurements of fluctuations in the integrated electron density or TEC (Total Electron Content) between three satellites (TOPEX-POSEIDON, SPOT2, SPOT4) and the ground have been done using the DORIS beacons. TEC has been also evaluated from a ground-based station using GPS satellites, and finally, ionospheric data from a classical ionospheric sounder located close to the earthquake epicenter are utilized. Anomalous electron density variations are detected both in day and night times before the quake. The generation mechanism of these perturbations is explained by a modification of the electric field in the global electric circuit induced during the earthquake preparation.

  14. Observations of ULF waves on the ground and ionospheric Doppler shifts during storm sudden commencement

    NASA Astrophysics Data System (ADS)

    Ouyang, Xinyan; Liu, Wenlong; Xiao, Zuo; Hao, Yongqiang

    2016-04-01

    Using data from ground-based magnetometers and HF Doppler sounder, we study ultralow frequency (ULF) waves excited during the storm sudden commencement (SSC) on 8 March 2012 and find possible evidence on the link between ULF waves and ionospheric Doppler shifts. Pc1-Pc2 ULF waves are observed from 11:04 to 11:27 UT after the SSC by ground stations of L shell ranging from 1.06 to 2.31, mapping to the topside ionosphere. There are weak responses in this frequency range in the power spectra of ionospheric Doppler shift. From 11:19 to 11:23 UT, oscillations of magnetic field in a lower frequency range of Pc3-Pc4 are observed and are well correlated with the trace of Doppler shift. It is thus suggested that ionospheric Doppler shift can response to ULF oscillations in magnetic field in various frequency ranges, especially in the frequency range of Pc3-Pc4 and below. This paper demonstrates a new mechanism of magnetosphere-ionosphere coupling.

  15. The effect of moving cold fronts over Central Europe to the variability of the ionosphere

    NASA Astrophysics Data System (ADS)

    Potuznikova, Katerina; Koucka Knizova, Petra; Boska, Josef; Sindelarova, Tereza; Mosna, Zbysek

    2015-04-01

    Cold fronts represent well known source of atmospheric waves, (especially short and medium scale AGW - acoustic gravity waves), that are able to propagate up to the ionospheric heights. In our study we focus on the effects of the transitions of cold front over the region of Central Europe on the variations of the ionosphere. We concentrate on periods of low solar and geomagnetic activity. Neutral atmosphere data are compared with the wave-like oscillations in the E and F layer. Our tropospheric data comprise synoptic maps on of 500 hPa and 850 hPa geopotential heights. Within ionospheric data we search for variability that is linked to the tropospheric disturbances. The ionospheric parameters (electron concentration and corresponding height) we analyse by the wavelet transform method. The Modern HF digisonde DPS-4 D (Digisonde Portable Sounder), which is in operation at the Pruhonice observatory (49.59 N; 14.33 E) of the Institute of Atmospheric Physics, Prague (IAP) since 2004, represents an excellent source of the ionospheric data for Central Europe. Pruhonice digisonde usually operates in standard mode - one ionogram and electron density profie N(h) each 15 minutes. Besides that, data from several european stations of the digisonde world network (data from Juliusruhe, Chilton, Brusel, Roma and Tortosa digisonde stations) are included in the study.

  16. Ionospheric S-shaped Doppler fluctuations produced by the tornadoes

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Rao, G. L.; Smith, R. E.

    1974-01-01

    A three-dimensional nine element HF-CW Doppler sounder array has been used to detect ionospheric disturbances which may be due to tornadoes. The typical events chosen in the present study occurred on November 20 and 27, 1973. Both events are apparently associated with tornadoes sighted in the Huntsville, Alabama area. The Doppler records show S-shaped waves rather than the quasi-sinusoidal waves observed in conjunction with and apparently due to thunderstorms. The wave-periods are in the range of 6 to 8 minutes instead of the 3 to 5 minute periods associated with thunderstorms. Dissipation of waves is mostly due to the evanescent effect and they cannot propagate very far from the path of the tornado center. A theory is presented which is in good agreement with the observations.

  17. Oblique sounding of an auroral ionospheric HF channel

    NASA Astrophysics Data System (ADS)

    Lundborg, Bengt; Broems, Mats; Derblom, Harald

    1995-01-01

    Observations of the HF skywave ionospheric channel during one year over three paths within Sweden are reported. The major aim of the work was to gain insight into prevailing propagation effects on representative fixed circuit paths at auroral latitudes, with a view to being able to assess prediction accuracies, and to exploite abnormal propagation modes so improving circuit reliabilities. The main instruments in the study were chirpsounders, HF FM-CW sounders covering the frequency range from 2 to 30 MHz. A data base of about 250,000 recordings was built up during the campaign, which covers the maximum of solar cylce 22. Some measurements were made with transmissions on fixed frequencies, mostly greater than 20 MHz.

  18. Ionospheric Data Assimilation

    NASA Astrophysics Data System (ADS)

    Schunk, R.; Scherliess, L.; Sojka, J.; Thompson, D.

    2003-04-01

    Ionospheric weather disturbances can have detrimental effects on a variety of civilian and military systems and operations. They can affect over-the-horizon (OTH) radars, HF communications, surveying and navigation systems, surveillance, spacecraft charging, power grids, pipelines, and the FAA's Wide-Area Augmentation System (WAAS). In an effort to mitigate the adverse effects of the ionosphere on these systems/operations, there is a strong emphasis on developing specification and forecast models. One of the models under development is the Global Assimilation of Ionospheric Measurements (GAIM) model. GAIM uses a physics-based ionosphere-plasmasphere-polar wind model and a Kalman filter as a basis for assimilating a diverse set of real-time (or near real-time) measurements. Some of the data that are assimilated include in situ electron density measurements from the DMSP satellites, bottomside electron density profiles from the Air Force network of digisondes, GPS-TEC data from a network of more than 100 stations, and occultation data. GAIM provides specifications and forecasts on a spatial grid that can be global, regional, or local (25 x 25 km). The primary GAIM output is in the form of 3-dimensional electron density distributions from 90 km to the geosynchronous altitude (35,000 km). GAIM also provides auxiliary parameters (N_mF_2, h_mF_2, N_mE, h_mE, slant and vertical TEC) and global distributions of the self-consistent ionospheric drivers (neutral winds and densities, magnetospheric and dynamo electric fields, and particle precipitation patterns). In its specification mode, GAIM provides quantitative estimates for the accuracy of the reconstructed ionospheric densities. An outline of the GAIM model will be presented and then the presentation will focus on data issues, including the availability of real-time data sources, data quality problems, and the need to have realistic errors attached to all of the real-time data.

  19. System Design and Technology Development for an Azimuth Scanning Microwave Limb Sounder

    NASA Astrophysics Data System (ADS)

    Stek, P. C.; Chattopadhyay, G.; Cofield, R.; Jarnot, R.; Kawamura, J.; Lee, K.; Livesey, N.; Ward, J.

    2007-12-01

    The NRC's Earth Science and Applications from Space decadal survey calls for a mission (GACM) to study global atmospheric composition, "with sufficient vertical resolution to detect the presence, transport, and chemical transformation of atmospheric layers from the surface to the lower stratosphere." Microwave limb sounding is particularly well suited for providing this information for the upper troposphere and above. The Microwave Limb Sounders on Aura and UARS have provided global measurements that have: quantified the evolution of the ozone layer; characterized the water vapor and cloud ice feedback mechanisms affecting climate change; documented the long range transport of pollution through tracers like CO; and improved the accuracy of global circulation models used for weather and climate forecasts. The Scanning Microwave Limb Sounder (SMLS) concept builds on the success of these instruments by adding an azimuth scan and increasing the antenna height to greatly improve horizontal and vertical resolution. The measurement swath is wide enough to provide, depending on orbit inclination, six or more daily measurements over midlatitudes. SMLS will incorporate a novel antenna design that enables rapid horizontal scanning, 4 Kelvin receiver front ends, advanced digital receiver back ends, and several lessons learned from previous missions. We will discuss the instrument design, technology development and readiness, and our approach to on-orbit calibration. We will also discuss plans and goals for a demonstration instrument that takes advantage of technologies developed through ESTO and other NASA and non-NASA programs. cameo.php

  20. NPOESS Preparatory Project Validation Program for the Cross-track Infrared Sounder

    NASA Astrophysics Data System (ADS)

    Barnet, C.; Gu, D.; Nalli, N. R.

    2009-12-01

    The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Program, in partnership with National Aeronautical Space Administration (NASA), will launch the NPOESS Preparatory Project (NPP), a risk reduction and data continuity mission, prior to the first operational NPOESS launch. The NPOESS Program, in partnership with Northrop Grumman Aerospace Systems, will execute the NPP Calibration and Validation (Cal/Val) program to ensure the data products comply with the requirements of the sponsoring agencies. The Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) are two of the instruments that make up the suite of sensors on NPP. Together, CrIS and ATMS will produce three Environmental Data Records (EDRs) including the Atmospheric Vertical Temperature Profile (AVTP), Atmospheric Vertical Moisture Profile (AVMP), and the Atmospheric Vertical Pressure Profile (AVPP). The AVTP and the AVMP are both NPOESS Key Performance Parameters (KPPs). The validation plans establish science and user community leadership and participation, and demonstrated, cost-effective Cal/Val approaches. This presentation will provide an overview of the collaborative data, techniques, and schedule for the validation of the NPP CrIS and ATMS environmental data products.

  1. Ionospheric and magnetospheric 'plasmapauses'

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    The locations of Explorer 45 plasmapause crossings are studied as a likely indicator of ionospheric and magnetospheric trough locations. Attention is given to vertical flows of H(+) ions in the light ion trough, as detected by the magnetic ion mass spectrometer aboard Isis 2 (which was operating in conjunction with Explorer 45 during August 1972). The possibility of an equatorial plasmapause is discussed, whose field lines map into the ionosphere at latitudes poleward of the H(+) density decrease, probably due to the refilling of magnetic flux tubes in the outer plasmasphere.

  2. Ionospheric reaction on sudden stratospheric warming events in Russiás Asia region

    NASA Astrophysics Data System (ADS)

    Polyakova, Anna; Perevalova, Natalya; Chernigovskaya, Marina

    2015-12-01

    The response of the ionosphere to sudden stratospheric warmings (SSWs) in the Asian region of Russia is studied. Two SSW events observed in 2008-2009 and 2012-2013 winter periods of extreme solar minimum and moderate solar maximum are considered. To detect the ionospheric effects caused by SSWs, we carried out a joint analysis of global ionospheric maps (GIM) of the total electron content (TEC), MLS (Microwave Limb Sounder, EOS Aura) measurements of temperature vertical profiles, as well as NCEP/NCAR and UKMO Reanalysis data. For the first time, it was found that during strong SSWs, in the mid-latitude ionosphere the amplitude of diurnal TEC variation decreases nearly half compared to quiet days. At the same time, the intensity of TEC deviations from the background level increases. It was also found that at SSW peak the midday TEC maximum decreases, and night/morning TEC values increase compared to quiet days. It was shown that during SSWs, TEC dynamics was identical for different geophysical conditions.The response of the ionosphere to sudden stratospheric warmings (SSWs) in the Asian region of Russia is studied. Two SSW events observed in 2008-2009 and 2012-2013 winter periods of extreme solar minimum and moderate solar maximum are considered. To detect the ionospheric effects caused by SSWs, we carried out a joint analysis of global ionospheric maps (GIM) of the total electron content (TEC), MLS (Microwave Limb Sounder, EOS Aura) measurements of temperature vertical profiles, as well as NCEP/NCAR and UKMO Reanalysis data. For the first time, it was found that during strong SSWs, in the mid-latitude ionosphere the amplitude of diurnal TEC variation decreases nearly half compared to quiet days. At the same time, the intensity of TEC deviations from the background level increases. It was also found that at SSW peak the midday TEC maximum decreases, and night/morning TEC values increase compared to quiet days. It was shown that during SSWs, TEC dynamics was

  3. Ionosphere Waves Service - A demonstration

    NASA Astrophysics Data System (ADS)

    Crespon, François

    2013-04-01

    In the frame of the FP7 POPDAT project the Ionosphere Waves Service was developed by ionosphere experts to answer several questions: How make the old ionosphere missions more valuable? How provide scientific community with a new insight on wave processes that take place in the ionosphere? The answer is a unique data mining service accessing a collection of topical catalogues that characterize a huge number of Atmospheric Gravity Waves, Travelling Ionosphere Disturbances and Whistlers events. The Ionosphere Waves Service regroups databases of specific events extracted by experts from a ten of ionosphere missions which end users can access by applying specific searches and by using statistical analysis modules for their domain of interest. The scientific applications covered by the IWS are relative to earthquake precursors, ionosphere climatology, geomagnetic storms, troposphere-ionosphere energy transfer, and trans-ionosphere link perturbations. In this presentation we propose to detail the service design, the hardware and software architecture, and the service functions. The service interface and capabilities will be the focus of a demonstration in order to help potential end-users for their first access to the Ionosphere Waves Service portal. This work is made with the support of FP7 grant # 263240.

  4. Multi-instrumental Analysis of the Ionospheric Density Response to Geomagnetic Disturbances

    NASA Astrophysics Data System (ADS)

    Zakharenkova, I.; Astafyeva, E.

    2014-12-01

    Measurements provided by Low Earth Orbit (LEO) satellite missions have already proved to be very efficient in investigations of global redistribution of ionospheric plasma and thermosphere mass density during such phenomena as geomagnetic storms. LEO satellites have various instruments for research of the ionosphere response to the space weather events like GPS receiver for precise orbit determination (POD), total electron content estimation and radio occultation, altimeter, planar Langmuir probe, topside sounder, special detectors for particle fluxes, magnetometer etc. In this paper, we present results of joint analysis of LEO satellite data, in particular CHAMP, DMSP, JASON, as well as data provided by ground-based networks of GPS receivers and ionosonde stations for global ionospheric response to the geomagnetic disturbances. We use in-situ plasma density data from CHAMP and DMSP satellites, along with data of GPS receiver onboard CHAMP-satellite and ground-based GPS-receivers to study occurrence and global distribution of ionospheric irregularities during the main phase of the storm. Using CHAMP GPS measurements, we created maps of GPS phase fluctuation activity and found two specific zones of the most intense irregularities - first is the region of the auroral oval at high latitudes of both hemispheres, the second one is the low-latitudes/equatorial region between Africa and South America. The interhemispheric asymmetry of the ionospheric irregularities intensity and occurrence in polar region is discussed. Analysis of the topside TEC, derived from CHAMP onboard GPS POD antenna, indicate the significant redistribution of the topside ionospheric plasma density in the equatorial, middle and high-latitude ionosphere during main and recovery phases of geomagnetic storm. Multi-instrumental data allow to analyze in detail the complex modification and dynamics of the upper atmosphere in different altitudinal, spatial and temporal scales.

  5. Global ionospheric weather

    SciTech Connect

    Decker, D.T.; Doherty, P.H.

    1994-02-28

    In the last year, the authors have studied several issues that are critical for understanding ionospheric weather. Work on global F-region modeling has consisted of testing the Phillips Laboratory Global Theoretical Ionosphere Model. Comparisons with both data and other theoretical models have been successfully conducted and are ongoing. GPS observations, as well as data analysis, are also ongoing. Data have been collected for a study on the limitations in making absolute ionospheric measurements using GPS. Another study on ionospheric variability is the first of its kind using GPS data. The observed seasonal total electron content behavior is consistent with that determined from the Faraday rotation technique. Work on the FAA's Phase 1 Wide Area Differential GPS (WADGPS) Satellite Navigation Testbed Experiment also continues. Initial results indicate that stations using operational WADGPS should be located no greater than 430 km apart. Work comparing the authors electron-proton-H atom model to both observations and other models has been generally successful. They have successfully modeled the creation of high-latitude large-scale plasma structures using two separate mechanisms (time-varying global convection and meso-scale convection events).

  6. Solitons and ionospheric heating

    NASA Technical Reports Server (NTRS)

    Weatherall, J. C.; Goldman, M. V.; Sheerin, J. P.; Nicholson, D. R.; Payne, G. L.; Hansen, P. J.

    1982-01-01

    It is noted that for parameters characterizing the Platteville ionospheric heating facility, the Langmuir wave evolution at the exact reflection point of the heater wave involves an oscillating two-stream instability followed by a collisionally damped three-dimensional soliton collapse. The result gives an alternative explanation for certain experimental observations.

  7. Study on the Boundary between the Ionosphere and the Magnetosheath from the Disappearance and Reappearance of Electron Plasma Oscillations

    NASA Astrophysics Data System (ADS)

    Duru, F.

    2013-05-01

    The radar sounder on the Mars Express Spacecraft is able to make measurements of electron densities in the Martian ionosphere from both local electron plasma oscillations and remote soundings. A study of thousands of orbits shows that in some cases the electron plasma oscillations disappear and reappear abruptly near the upper boundary of the dayside ionosphere. This study investigates these cases and explores possibilities which could cause these time variations with the help of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) Electron Spectrometer (ELS) and Ion Mass Analyzer (IMA) data. Study of the ion spectra through ASPERA-3 data shows upward acceleration of ionospheric ions and downward acceleration of electrons. All this information favors the possibility that the events are related to auroral density cavities. Another reason for these intermittent appearances of electron plasma oscillations can be the multiple crossings of the boundary between the ionosphere and magnetosheath. The motion of the boundary between the ionosphere in response to the solar wind, or plasma clouds or ionospheric streamers with sizes ranging between about 500 and 3000 km along the trajectory could cause multiple crossings. When a quasi - sinusoidal oscillation of the boundary is assumed, the periods of oscillation are found to be around 7 min, and the amplitudes of the velocity are less than 20 km/s.

  8. 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

  9. Martian ionosphere response to solar wind variability during solar minimum

    NASA Astrophysics Data System (ADS)

    Sanchez-Cano, Beatriz; Lester, Mark; Witasse, Olivier; Mays, M. Leila; Hall, Benjamin E. S.; Milan, Stephen E.; Cartacci, Marco; Blelly, Pierre-Louis; Andrews, David; Opgenoorth, Hermann; Odstrcil, Dusan

    2016-04-01

    Solar cycle variations in solar radiation create notable density changes in the Martian ionosphere. In addition to this long-term variability, there are numerous short-term and non-recurrent solar events that hit Mars which need to be considered, such as Interplanetary Coronal Mass Ejections (ICMEs), Co-Rotation Interaction Regions (CIRs), solar flares, or solar wind high speed streams. The response of the Martian plasma system to each of these events is often unusual, especially during the long period of extreme low solar activity in 2008 and 2009. This work shows the long-term solar cycle impact on the ionosphere of Mars using data from The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), and The Analyzer of Space Plasma and Energetic Atoms (ASPERA-3), and with empirical and numerical models on Mars Express. Particular attention is given to the different ionospheric responses observed during the last, extended solar minimum. Mars' ionospheric response followed a similar pattern to the response observed in the Earth's ionosphere, despite the large differences related to the inner-origin of the magnetic field of both planets. The ionospheric temperature was cooler, the topside scale height was smaller and almost constant with altitude, the secondary ionospheric layer practically disappeared and the whole atmospheric total electron content (TEC) suffered an extreme reduction of about 30-40%, not predicted before by models. Moreover, there is a larger probability for the induced magnetic field to be present in the ionosphere, than in other phases of the solar cycle. The short-term variability is also addressed with the study of an ICME followed by a fast stream that hit Mars in March 2008, where solar wind data are provided by ACE and STEREO-B and supported by simulations using the WSA-ENLIL Model. The solar wind conditions lead to the formation of a CIR centred on the interface of the fast and the slow solar wind streams. Mars' system reacted to

  10. Next Generation Grating Spectrometer Sounders for LEO and GEO

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.

    2011-01-01

    AIRS and MODIS are widely used for weather, climate, composition, carbon cycle, cross-calibration, and applications. The community asking for new capability in the 2020 timeframe, capabilities desired: (1) Hyperspectral UV to LWIR, High Spatial ?1km IFOV (2) Maximize Synergies of Solar Reflected and IR. Synergies with OCO-2. We expect more users and applications of next gen LEO IR Sounder than GEO. These include: weather, climate, GHG monitoring, aviation, disaster response. There is a new direction for imagers and sounders: (1) Separate Vis/NIR/SWIR from MWIR/LWIR instruments reduces technology risk and complexity. (2) Expect Costs to be lower than CrIS & VIIRS Some additional ideas to reduce costs include: (1) minimum set of requirements (2) mini-grating spectrometers. supports constellation for higher revisit (3) new technology to reduce instrument size (large format fpa's) (4) hosted payloads

  11. Ultraspectral sounder data compression using the Tunstall coding

    NASA Astrophysics Data System (ADS)

    Wei, Shih-Chieh; Huang, Bormin; Gu, Lingjia

    2007-09-01

    In an error-prone environment the compression of ultraspectral sounder data is vulnerable to error propagation. The Tungstall coding is a variable-to-fixed length code which compresses data by mapping a variable number of source symbols to a fixed number of codewords. It avoids the resynchronization difficulty encountered in fixed-to-variable length codes such as Huffman coding and arithmetic coding. This paper explores the use of the Tungstall coding in reducing the error propagation for ultraspectral sounder data compression. The results show that our Tunstall approach has a favorable compression ratio compared with JPEG-2000, 3D SPIHT, JPEG-LS, CALIC and CCSDS IDC 5/3. It also has less error propagation compared with JPEG-2000.

  12. SAR/InSAR observation by an HF sounder

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Ono, T.

    2007-03-01

    Application of SAR imaging algorithm to spaceborne HF sounder observation was studied. Two types of image ambiguity problems were addressed in the application. One is surface/subsurface image ambiguity arising from deep penetration of HF wave, and another is mirror image ambiguity that is inherent to dipole antenna SAR. A numerical model demonstrated that the surface/subsurface ambiguity can be mitigated by taking a synthetic aperture large enough to defocus subsurface objects. In order to resolve the mirror image ambiguity problem, an image superposition technique was proposed. The performance of the technique was demonstrated by using simulation data of the HF sounder observation to confirm the feasibility of HF SAR and HF InSAR observation.

  13. The thermosphere and ionosphere of Venus

    NASA Technical Reports Server (NTRS)

    Cravens, T. E.

    1992-01-01

    Our knowledge of the upper atmosphere and ionosphere of Venus and its interaction with the solar wind has advanced dramatically over the last decade, largely due to the data obtained during the Pioneer Venus mission and to the theoretical work that was motivated by this data. Most of this information was obtained during the period 1978 through 1981, when the periapsis of the Pioneer Venus Orbiter (PVO) was still in the measurable atmosphere. However, solar gravitational perturbations will again lower the PVO periapsis into the upper atmosphere in September 1992, prior to the destruction of the spacecraft toward the end of this year. The physics and chemistry of the thermosphere and ionosphere of Venus are reviewed.

  14. HIS analyses of mesoscale phenomena. [High resolution Interferometer Sounder

    NASA Technical Reports Server (NTRS)

    Bradshaw, John T.; Fuelberg, Henry E.

    1990-01-01

    Results are presented from two sets of measurements made by the High-resolution Interferometer Sounder (HIS) during two aircraft flights over the Cooperative-Huntsville-Meteorological-Experiment region on June 15 and 19, 1986. It is shown that the temperature and the dew-point field retrieved from HIS spectra contain distinct mesoscale structures. The features in the HIS dew-point fields agreed well with the cloud and moisture structures observed in visible and 6.7 micron GOES imagery.

  15. High resolution microwave spectrometer sounder (HIMSS), volume 1, book 1

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The following topics are presented with respect to the high resolution microwave spectrometer sounder (HIMSS) that is to be used as an instrument for NASA's Earth Observing System (EOS): (1) an instrument overview; (2) an instrument description; (3) the instrument's conceptual design; (4) technical risks and offsets; (5) instrument reliability; (6) commands and telemetry; (7) mass and power budgets; (8) integration and test program; (9) program implementation; and (10) phase CD schedule.

  16. The Apollo 17 Lunar Sounder. [lunar orbit coherent radar experiment

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.; Brown, W. E., Jr.; Jordan, R.; Adams, G. F.; Jackson, P.; Peeples, W. J.; Porcello, L. J.; Ryu, J.; Eggleton, R. E.; Schaber, G.

    1973-01-01

    The Apollo Lunar Sounder Experiment, a coherent radar operated from lunar orbit during the Apollo 17 mission, has scientific objectives of mapping lunar subsurface structure, surface profiling, surface imaging, and galactic noise measurement. Representative results from each of the four disciplines are presented. Subsurface reflections have been interpreted in both optically and digitally processed data. Images and profiles yield detailed selenomorphological information. The preliminary galactic noise results are consistent with earlier measurements by other workers.

  17. On Cirrus Cloud Fields Measured by the Atmospheric Infrared Sounder

    NASA Technical Reports Server (NTRS)

    Kahn, Brian H.; Eldering, Annmarie; Liou, Kuo Nan

    2006-01-01

    A viewgraph presentation showing trends in clouds measured by the Atmospheric Infrared Sounder (AIRS) is given. The topics include: 1) Trends in clouds measured by AIRS: Are they reasonable? 2) Single and multilayered cloud trends; 3) Retrievals of thin cirrus D(sub e) and tau: Single-layered cloud only; 4) Relationships between ECF, D(sub e), tau, and T(sub CLD); and 5) MODIS vs. AIRS retrievals.

  18. High resolution microwave spectrometer sounder (HIMSS), volume 1, book 2

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The following topics are presented with respect to the high resolution microwave spectrometer sounder (HIMSS) that is to be used as an instrument for NASA's Earth Observing System (EOS): (1) preliminary program plans; (2) contract end item (CEI) specification; and (3) the instrument interface description document. Under the preliminary program plans section, plans dealing with the following subject areas are discussed: spares, performance assurance, configuration management, software implementation, contamination, calibration management, and verification.

  19. Daily global maps of carbon monoxide from NASA's Atmospheric Infrared Sounder

    NASA Astrophysics Data System (ADS)

    McMillan, W. W.; Barnet, C.; Strow, L.; Chahine, M. T.; McCourt, M. L.; Warner, J. X.; Novelli, P. C.; Korontzi, S.; Maddy, E. S.; Datta, S.

    2005-06-01

    We present the first observations of tropospheric carbon monoxide (CO) by the Atmospheric Infrared Sounder (AIRS) onboard NASA's Aqua satellite. AIRS daily coverage of ~70% of the planet represents a significant evolutionary advance in satellite trace gas remote sensing. Tropospheric CO abundances are retrieved from AIRS 4.55 μm spectral region using the full AIRS retrieval algorithm run in a research mode. The presented AIRS daily global CO maps from 22-29 September 2002 show large-scale, long-range transport of CO from anthropogenic and natural sources, most notably from biomass burning. The sequence of daily maps reveal CO advection from Brazil to the South Atlantic in qualitative agreement with previous observations. Forward trajectory analysis confirms this scenario and indicates much longer range transport into the southern Indian Ocean. Preliminary comparisons to in situ aircraft profiles indicate AIRS CO retrievals are approaching the 15% accuracy target set by pre-launch simulations.

  20. Satellite Sounder Data Assimilation for Improving Alaska Region Weather Forecast

    NASA Technical Reports Server (NTRS)

    Zhu, Jiang; Stevens, E.; Zhang, X.; Zavodsky, B. T.; Heinrichs, T.; Broderson, D.

    2014-01-01

    A case study and monthly statistical analysis using sounder data assimilation to improve the Alaska regional weather forecast model are presented. Weather forecast in Alaska faces challenges as well as opportunities. Alaska has a large land with multiple types of topography and coastal area. Weather forecast models must be finely tuned in order to accurately predict weather in Alaska. Being in the high-latitudes provides Alaska greater coverage of polar orbiting satellites for integration into forecasting models than the lower 48. Forecasting marine low stratus clouds is critical to the Alaska aviation and oil industry and is the current focus of the case study. NASA AIRS/CrIS sounder profiles data are used to do data assimilation for the Alaska regional weather forecast model to improve Arctic marine stratus clouds forecast. Choosing physical options for the WRF model is discussed. Preprocess of AIRS/CrIS sounder data for data assimilation is described. Local observation data, satellite data, and global data assimilation data are used to verify and/or evaluate the forecast results by the MET tools Model Evaluation Tools (MET).

  1. GEO/SAMS - The Geostationary Synthetic Aperture Microwave Sounder

    NASA Technical Reports Server (NTRS)

    Lambrigtsen, Bjorn H.

    2008-01-01

    The National Oceanic and Atmospheric Administration (NOAA) has for many years operated two weather satellite systems, the Polar-orbiting Operational Environmental Satellite system (POES), using low-earth orbiting (LEO) satellites, and the Geostationary Operational Environmental Satellite system (GOES), using geostationary earth orbiting (GEO) satellites. (Similar systems are also operated by other nations.) The POES satellites have been equipped with both infrared (IR) and microwave (MW) atmospheric sounders, which makes it possible to determine the vertical distribution of temperature and humidity in the troposphere even under cloudy conditions. Such satellite observations have had a significant impact on weather forecasting accuracy, especially in regions where in situ observations are sparse. In contrast, the GOES satellites have only been equipped with IR sounders, since it has not been feasible to build a large enough antenna to achieve sufficient spatial resolution for a MW sounder in GEO. As a result, GOES soundings can only be obtained in cloud free areas and in the less important upper atmosphere, above the cloud tops. This has hindered the effective use of GOES data in numerical weather prediction. Full sounding capabilities with the GOES system is highly desirable because of the advantageous spatial and temporal coverage that is possible from GEO. While POES satellites provide coverage in relatively narrow swaths, and with a revisit time of 12-24 hours or more, GOES satellites can provide continuous hemispheric coverage, making it possible to monitor highly dynamic phenomena such as hurricanes.

  2. Application of Atmospheric Infrared Sounder (AIRS) Data to Climate Research

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Gregorich, David; Gaiser, Steve; Chahine, Moustafa T.

    2004-01-01

    The application of hyper spectral radiometric data to climate research requires very high absolute radiometric accuracy and stability. We use cloud-free tropical ocean data from the Atmospheric InfraRed Sounder (AIR) Calibration Data Subset (ADCS) to show that the radiometric precision and stability required climate applications has been achieved. The sea surface skin temperatures derived from the AIRS 2616cm-1 super window channel are stable relative to the RTG.SST at the better than 8 mK/year level, and the spectral calibration is stable at the 1 ppm/year level. The excellent stability and accuracy are the result of the implementation of AIRS as a grating array spectrometer, which is cooled and stabilized within 10 mK at 155 K. Analysis of daily measurements of the temperature gradient between the surface and 7 km altitude show that the AIRS Calibration Data Subset has applications which extend its original intent for calibration support to climate research. The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua satellite was launched into polar orbit in May 2002. AIRS covers the spectral region from 640 to 2700 cm-1 with 2378 independent channels and represents the first of a new generation of hyper spectral resolution sounders in support of global sounding data for weather forecasting and climate research.

  3. 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…

  4. Carbon Monoxide Distribution over Peninsular Malaysia from the Atmospheric Infrared Sounder (AIRS)

    NASA Astrophysics Data System (ADS)

    Rajab, Jaso M.; MatJafri, M. Z.; Lim, H. S.; Abdullah, K.

    2009-07-01

    The Atmospheric Infrared Sounder (AIRS) onboard NASA's Aqua satellite. It daily coverage of ˜70% of the planet represents a significant evolutionary advance in satellite traces gas remote sensing. AIRS, the part of a large international investment to upgrade the operational meteorological satellite systems, is first of the new generation of meteorological advanced sounders for operational and research use, Providing New Insights into Weather and Climate for the 21st Century. Carbon monoxide (CO) is a ubiquitous, an indoor and outdoor air pollutant, is not a significant greenhouse gas as it absorbs little infrared radiation from the Earth. However, it does have an influence on oxidization in the atmosphere through interaction with hydroxyl radicals (OH), which also react with methane, halocarbons and tropospheric ozone. It produced by the incomplete combustion of fossil fuels and biomass burning, and that it has a role as a smog. The aim of this investigation is to study the (CO) carbon monoxide distribution over Peninsular Malaysia. The land use map of the Peninsular Malaysia was conducted by using CO total column amount, obtained from AIRS data, the map & data was processed and analyzed by using Photoshop & SigmaPlot 11.0 programs and compared for timing of various (day time) (28 August 2005 & 29 August 2007) for both direct comparison and the comparison using the same a priori profile, the CO concentrations in 28/8/2005 higher. The CO maps were generated using Kriging Interpolation technique. This interpolation technique produced high correlation coefficient, R2 and low root mean square error, RMS for CO. This study provided useful information for influence change of CO concentration on varies temperature.

  5. A regional adaptive and assimilative three-dimensional ionospheric model

    NASA Astrophysics Data System (ADS)

    Sabbagh, Dario; Scotto, Carlo; Sgrigna, Vittorio

    2016-03-01

    A regional adaptive and assimilative three-dimensional (3D) ionospheric model is proposed. It is able to ingest real-time data from different ionosondes, providing the ionospheric bottomside plasma frequency fp over the Italian area. The model is constructed on the basis of empirical values for a set of ionospheric parameters Pi[base] over the considered region, some of which have an assigned variation ΔPi. The values for the ionospheric parameters actually observed at a given time at a given site will thus be Pi = Pi[base] + ΔPi. These Pi values are used as input for an electron density N(h) profiler. The latter is derived from the Advanced Ionospheric Profiler (AIP), which is software used by Autoscala as part of the process of automatic inversion of ionogram traces. The 3D model ingests ionosonde data by minimizing the root-mean-square deviation between the observed and modeled values of fp(h) profiles obtained from the associated N(h) values at the points where observations are available. The ΔPi values are obtained from this minimization procedure. The 3D model is tested using data collected at the ionospheric stations of Rome (41.8N, 12.5E) and Gibilmanna (37.9N, 14.0E), and then comparing the results against data from the ionospheric station of San Vito dei Normanni (40.6N, 18.0E). The software developed is able to produce maps of the critical frequencies foF2 and foF1, and of fp at a fixed altitude, with transverse and longitudinal cross-sections of the bottomside ionosphere in a color scale. fp(h) and associated simulated ordinary ionogram traces can easily be produced for any geographic location within the Italian region. fp values within the volume in question can also be provided.

  6. Ensemble Ionospheric Total Electron Content Forecasting during Storms

    NASA Astrophysics Data System (ADS)

    Chartier, A.; Mitchell, C. N.; Lu, G.; Anderson, J. L.; Collins, N.; Hoar, T. J.; Bust, G. S.; Matsuo, T.

    2014-12-01

    Earth's ionosphere presents a threat to human activities such as satellite positioning and timing, radio communications and surveillance. Nowcasts and forecasts of the ionosphere could help mitigate these damaging effects. Recent advances in the field of ionospheric imaging, as well as new storm-time ionospheric forecasting results are presented here. The approach combines globally distributed GPS Total Electron Content (TEC) measurements with an ensemble of coupled thermosphere-ionosphere models in order to produce short-term forecasts during a storm. One-hour forecast accuracy is much better than a climatological model run. Using this ensemble approach, it is possible to infer the neutral O/N2 ratio from TEC measurements so that subsequent TEC forecasts are improved. A review of ionospheric physics and data assimilation will also be given. The term data assimilation refers to a group of techniques designed to estimate atmospheric or oceanic states. In practice, data assimilation techniques seek to improve modeled estimates of the atmospheric state by incorporating observations. The relationship between data assimilation and forecasting is explored with reference to the physics of the thermosphere-ionosphere system. The work presented here uses the Data Assimilation Research Testbed (DART), which is an ensemble Kalman filter data assimilation framework. This is combined with a version of the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) that has been modified to accept more detailed solar and geomagnetic driver specifications. Future directions of work include the inference of Solar and geomagnetic drivers from the data assimilation process as well as coupling with lower-atmospheric models.

  7. Comparison of Natural Narrow-banded Emissions and Sounder Stimulated Resonances In The Magnetospheres of Jupiter and The Earth (ulysses and Image Spacecraft)

    NASA Astrophysics Data System (ADS)

    Osherovich, V. A.; Fainberg, J.; Benson, R. F.; MacDowall, R.

    The sounder stimulated resonances observed by Ulysses in JupiterSs Io torus re- vealed a spectrum of frequencies which has been interpreted in terms of Dn reso- nances together with electron plasma frequency fpe and Bernstein Qn resonances in order to determine the electron density and magnetic field strength (Osherovich et al. 1993; Benson et al. 1997). The presence of Dn resonances (cylindrical eigen- modes with frequencies proportional sqrtn, n = 1, 2, ...) has been predicted for the Io torus on the basis of the classification of the EarthSs Ionospheric sounder stim- ulated resonances (Osherovich 1987, 1989; Osherovich and Benson 1991; Benson and Osherovich 1992). The magnetic field strength measured by the Ulysses mag- netometer confirmed the values found from resonances to within a few percent. An alternative interpretation suggested that the Ulysses relaxation sounder did not excite Dn in JupiterSs magnetosphere( Le Sagre et al. 1998) and the topic has been subject to a recent debate (Canu 2001a; Benson et al. 2001; Canu 2001b) . We show that Dn resonances are present in both sounder stimulated spectra and in natural emissions ob- served by Ulysses during the inbound and outbound part of the trajectory inside the Io torus. The natural emissions (no sounding) have the same frequencies as their sounder stimulated counterparts. IMAGE/RPI observations, which confirm the specific rela- tion between Dn, fp and fce and for the subsidiary resonances Dn+ and Dn-, will also be presented. References: Benson, R.F. and V.A. Osherovich, Canu, J. Geophys. Res., 97, 19413, 1992. Benson, R.F. et al., Radio Sci., 32, 1127, 1997. Benson, R.F. et al., Radio Sci., 36, 1649, 2001. Canu, P., Radio Sci., 36, 171, 2001a. Canu, P., Radio Sci., 36, 1645, 2001b. Le Sagre, P. et al., J. Geophys. Res., 103, 26667, 1998. 1 Osherovich, V. A., J. Geophys. Res., 92, 316, 1987. Osherovich, V. A., J. Geophys. Res., 94, 5530, 1989. Osherovich, V. A. and R.F. Benson, ., J. Geophys. Res., 96

  8. Variability of Electron Densities in the Low-Altitude Martian Nightside Ionosphere Derived from the Intensity of Marsis AIS Surface Reflections

    NASA Astrophysics Data System (ADS)

    Nemec, F.; Morgan, D. D.; Gurnett, D. A.

    2014-12-01

    Sounding signals at frequencies higher than the ionospheric peak plasma frequency are not reflected by the ionosphere. Instead they make it to the ground where they are reflected by the planetary surface. We analyze the intensity of the surface reflections measured by the MARSIS ionospheric radar sounder on board the Mars Express spacecraft. Apart from the surface reflectivity, the intensity of the surface reflection is controlled primarily by the signal attenuation during ionospheric propagation. We focus on the nightside region, where the ionospheric densities in the main layer are too low to cause a significant attenuation and allow sampling of the surface reflection at frequencies down to 3 MHz. The attenuation is then expected to occur mainly at lower altitudes (<100 km), where electron-neutral collision frequency is a maximum. The intensity of surface reflections can thus serve as a proxy for the electron density at low altitudes not accessible by the direct MARSIS ionospheric radar sounding. We derive the intensity of surface reflections from all available MARSIS nightside ionograms, and we analyze its variability as a function of relevant controlling factors such as SZA, solar activity, magnetic field magnitude and inclination, and simultaneously observed electron density in the main ionospheric layer. The results obtained are discussed in terms of possible processes affecting the electron densities at low altitudes.

  9. 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.

  10. 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.

  11. 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].

  12. Analysis of test data film generated by the lunar sounder (S-209)

    NASA Technical Reports Server (NTRS)

    Massey, N.

    1973-01-01

    The analysis of test films pertaining to the readiness of the Apollo 17 radar equipment is discussed. Emphasis is placed on the evaluation of the lunar sounder equipment. The lunar sounder experiment was to examine the lunar surface at three different radar frequencies of 2 meters, 60 meters, and 20 meters. Test films were made on the lunar sounder system to describe the purpose of the test, to describe the experiments used for analysis, and to provide conclusions reached after analysis.

  13. Coupled Magnetotail-Ionosphere Asymmetries from Ionospheric Hall Conduction

    NASA Astrophysics Data System (ADS)

    Lotko, W.; Smith, R. H.; Zhang, B.; Ouellette, J.; Brambles, O.; Lyon, J.; Wiltberger, M. J.

    2014-12-01

    Fast convective transport in the plasma sheet is more prevalent in the premidnight (dusk) sector relative to postmidnight. Ionospheric convection exhibits related asymmetries - more flux typically circulates in the dusk cell than in the dawn cell, and the nightside convection pattern is rotated clockwise when viewed over the North Pole. We show, using global simulations of the solar wind-magnetosphere-ionosphere interaction, that the electrodynamic interaction between Earth's magnetosphere and ionosphere produces asymmetries resembling observed distributions in plasmasheet flows and ionospheric convection (Figure, center panel). The primary causal agent in the simulations is a meridional gradient in ionospheric Hall conductance which, through Cowling polarization, regulates the distributions of i) electrical currents flowing within and between the ionosphere and magnetotail and ii) the nightside reconnection rate and resulting dawn-dusk distribution of plasma sheet fast flows. The asymmetry disappears in the simulation when the Hall conductance is taken to be uniform (left panel), and it reverses when the conductance is artificially depleted at auroral latitudes (right panel). The coupling between meridional currents and electric fields in the ionosphere and axial currents and electric fields in the plasmasheet is demonstrated by a simple model for non-ideal coupling of field-aligned currents flowing between the plasma sheet and the region of enhanced ionospheric conductance straddling the nightside convection throat.

  14. Value-added Impact from Future Geostationary Hyperspectral Infrared Sounder Observations on Hurricane Forecasts

    NASA Astrophysics Data System (ADS)

    Li, J.; Schmit, T. J.; Li, Z.; Zhu, F.; Lim, A.; Atlas, R. M.; John, P.

    2015-12-01

    Future geostationary (Geo) advanced InfraRed (IR) sounders have finer spatial, spectral, and temporal resolutions compared with the existing GOES sounders, providing much improved resolving power of atmospheric thermodynamic information. When quantitatively assessing the value-added impact from such instruments over the current sounding systems onboard the Low Earth Orbit (Leo) satellites, the real question is what is the optimal impact using the current assimilation/forecast systems. More specifically, will assimilation of more observations from Geo IR sounders with the current assimilation/forecast systems yield improved forecast as expected? And if so, how to assimilate the high temporal resolution Geo sounding information and what is the impact on forecasts? Taken tropical cyclone (TC) forecasting as an example, this study tries to address these questions through a quick regional Observing System Simulation Experiments (r-OSSE) study. The synthetic observations are simulated from the sample ECMWF T1279 nature run (NR) for Hurricane Sandy (2012), including RAOB, the Leo AIRS, and Geo AIRS. Various experiments were carried out using WRF 3.6.1 and GSI 3.3 to study the impact on Sandy track forecast. And the study shows that a) it is critical to assign an appropriate observational error (observation error covariance matrix - O matrix) in order to show improved positive impacts from Geo AIRS over Leo AIRS; b) cycling of 3/6-hourly shows improved positive impacts over none cycling, but hourly cycling does not show further improvement on forecasts among all experiments, and c) with thinning (120 ~ 240 km), the impacts have the following order: hourly > 3-hourly > 6-hourly > none cycling. These experiments indicate that while more observations may improve forecasts, much more observations are difficult to show further improvement with the current assimilation/forecast system configurations. There exists a tradeoff between the number of observations to be assimilated

  15. Anomalous reflections from the ionosphere

    NASA Astrophysics Data System (ADS)

    Givishvili, G. V.; Leshchenko, L. N.

    2013-09-01

    The existence of anomalous ionospheric reflections was shown on the basis of vertical soundings at the Moskow station. They are observed at heights of 100-200 km. These anomalous reflections are not related to the main Ne( h) ionospheric profile. Morphological characteristics of such reflections are presented: the daily, seasonal, and cyclic dependences of their appearance.

  16. Observations and trends of clouds based on GOES sounder data

    NASA Astrophysics Data System (ADS)

    Schreiner, Anthony J.; Schmit, Timothy J.; Menzel, W. Paul

    2001-01-01

    A 26 month (November 1997 through December 1999) data set of Geostationary Operational Environmental Satellite (GOES) sounder-derived cloud parameters has been analyzed to discern annual and monthly trends. An important outcome of this study is the identification of diurnal trends made possible by the geostationary satellite frequent observations over specific locations. The area of coverage is 20°N to 50°N and 60°W to 160°W, which corresponds to the continental United States and the surrounding waters. The satellite cloud observations were compared to manually observed Pilot Reports (PIREPs) and were found to be, on average, 35 hPa lower. Comparing the frequency of GOES sounder observations of high cloudiness with observations from the National Oceanic and Atmospheric Administration (NOAA) series of polar orbiting weather satellites reveals a correlation coefficient of 0.79 and a bias of 3.4% for the frequency of occurrence (GOES with a mean higher height). The frequency of occurrence and distribution of clouds, cloud top pressure (CTOP), and effective cloud amount are based on a spatial resolution of ˜40 km (3×3 field of view box) and are shown for eight regions. High clouds (CTOP ≤300 hPa) are found to be more prevalent during the Northern Hemisphere summer than winter for all regions. High clouds for 1998 comprise 8.5% of all observations. Also, in 1998 clear conditions are observed ˜34% of the time. Focusing on the strength of the hourly GOES sounder data, it is found that thin high clouds are most prevalent during the summer and fall seasons, occurring most frequently in the late morning and early afternoon.

  17. Broadband infrared beam splitter for spaceborne interferometric infrared sounder.

    PubMed

    Yu, Tianyan; Liu, Dingquan; Qin, Yang

    2014-10-01

    A broadband infrared beam splitter (BS) on ZnSe substrate used for the spaceborne interferometric infrared sounder (SIIRS) is studied in the spectral range of 4.44-15 μm. Both broadband antireflection coating and broadband beam-splitter coating in this BS are designed and tested. To optimize the optical properties and the stability of the BS, suitable infrared materials were selected, and improved deposition techniques were applied. The designed structures matched experimental data well, and the properties of the BS met the application specification of SIIRS. PMID:25322240

  18. GEOSTAR - a microwave sounder for GOES-R

    NASA Technical Reports Server (NTRS)

    Lambrigtsen, Bjorn; Wilson, William; Tanner, Alan

    2005-01-01

    The National Oceanic and Atmospheric Administration (NOAA) has for many years operated two weather satellite systems, the Polar-orbiting Operational Environmental Satellite system (POES), using low-earth orbiting (LEO) satellites, and the Geostationary Operational Environmental Satellite system (GOES), using geostationary earth orbiting (GEO) satellites. Similar systems are also operated by other nations. The POES satellites have been equipped with both infrared (IR) and microwave (MW) atmospheric sounders, which together make it possible to determine the vertical distribution of temperature and humidity in the troposphere even under cloudy conditions.

  19. Multiorder etalon sounder (MOES) development and test for balloon experiment

    NASA Technical Reports Server (NTRS)

    Hays, Paul B.; Wnag, Jinxue; Wu, Jian

    1993-01-01

    The Fabry-Perot interferometer (FPI), with its high throughput and high spectral resolution has been used in the remote-sensing measurements of the earth's atmospheric composition, winds, and temperatures. The most recent satellite instruments include the Fabry-Perot interferometer flown on the Dynamics Explorer-2 (DE-2), the High Resolution Doppler Imager (HRDI), and the Cryogenic Limb Array Etalon Spectrometer (CLAES) flown on the Upper Atmosphere Research Satellite (UARS). These instruments measure the Doppler line profiles of the emission and absorption of certain atmospheric species (such as atomic oxygen) in the visible and infrared spectral region. The successful space flight of DE-FPI, HRDI, and CLAES on UARS demonstrated the extremely high spectral resolution and ruggedness of the etalon system for the remote sensing of earth and planetary atmospheres. Recently, an innovative FPI focal plane detection technique called the Circle-to-Line Interferometer Optical (CLIO) system was invented at the Space Physics Research Laboratory. The CLIO simplifies the FPI focal plane detection process by converting the circular rings or fringes into a linear pattern similar to that produced by a conventional spectrometer, while retaining the throughput advantage of the etalon interferometer. The combination of FPI and CLIO allows the development of more sensitive Fabry-Perot interferometers in the infrared for the remote sensing of the lower atmospheres of Earth and possibly other planets. The Multiorder Etalon Sounder (MOES), a combination of the rugged etalon and the CLIO, compares very favorably to other space-borne optical instruments in terms of performance versus complexity. The new instrument is expected to be rugged, compact, and very suitable for an operational temperature and moisture sounder. With this technique, the contamination of radiance measurements by emissions of other gases is also minimized. At the Space Physics Research Laboratory (SPRL), the MOES

  20. Improving Regional Forecast by Assimilating Atmospheric InfraRed Sounder (AIRS) Profiles into WRF Model

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Brad; Jedlovec, Gary J.

    2009-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and produce improved forecasts. One such source comes from the Atmospheric InfraRed Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), represents one of the most advanced space-based atmospheric sounding systems. The purpose of this paper is to describe a procedure to optimally assimilate high resolution AIRS profile data into a regional configuration of the Advanced Research WRF (ARW) version 2.2 using WRF-Var. The paper focuses on development of background error covariances for the regional domain and background type, and an optimal methodology for ingesting AIRS temperature and moisture profiles as separate overland and overwater retrievals with different error characteristics. The AIRS thermodynamic profiles are derived from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm and contain information about the quality of each temperature layer. The quality indicators were used to select the highest quality temperature and moisture data for each profile location and pressure level. The analyses were then used to conduct a month-long series of regional forecasts over the continental U.S. The long-term impacts of AIRS profiles on forecast were assessed against verifying NAM analyses and stage IV precipitation data.

  1. Solitons and ionospheric modification

    NASA Technical Reports Server (NTRS)

    Sheerin, J. P.; Nicholson, D. R.; Payne, G. L.; Hansen, P. J.; Weatherall, J. C.; Goldman, M. V.

    1982-01-01

    The possibility of Langmuir soliton formation and collapse during ionospheric modification is investigated. Parameters characterizing former facilities, existing facilities, and planned facilities are considered, using a combination of analytical and numerical techniques. At a spatial location corresponding to the exact classical reflection point of the modifier wave, the Langmuir wave evolution is found to be dominated by modulational instability followed by soliton formation and three-dimensional collapse. The earth's magnetic field is found to affect the shape of the collapsing soliton. These results provide an alternative explanation for some recent observations.

  2. The use of multibeam and split-beam echo sounders for assessing biomass and distribution of spring-spawning Atlantic cod in the Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Gurshin, Christopher William Damon

    This research focused on advancing the application of split-beam and multibeam echo sounding to remotely locate and describe spatial distribution, and to provide a relative measure of abundance of the spring-spawning Atlantic cod (Gadus morhua) in the western Gulf of Maine. Specifically, the main objectives of this research were 1) to test the feasibility of a multibeam echo sounder to detect changes in volume backscatter proportional to incrementally decreasing quantities of cod held in a submerged cage, and to compare results to a split-beam echo sounder; 2) to describe the spatio-temporal distribution and estimate biomass of spring-spawning cod in the Gulf of Maine cod spawning protection area (GOMCSPA) by repeated acoustic and trawl surveys; and 3) to determine a predictive relation between target strength and length for 38-kHz and 120-kHz split-beam echo sounders and a 300-kHz multibeam echo sounder, and characterize other factors affecting backscattering of sound. The multibeam echo sounder detected a small and large reduction in volume backscatter proportional to reductions in stocking density of caged cod, while the split-beam echo sounder only detected a large reduction in stocking density. The spatial information from the multibeam echo sounder helped interpret and explain results from the split-beam echo sounder. Repeated acoustic and trawl surveys showed cod were relatively widespread in the survey area in May, but congregated at higher densities in areas adjacent to two elevated bathymetric features. Most cod converged to a single location in June, and were at a higher concentration than observations in May. This congregation decreased in size and density in July. Survey estimates of cod biomass ranged 184-494 mt in May, 138-617 mt in June, and 39-135 mt in July, depending on the estimation method. Based on echo classification and extrapolation, cod biomass to the GOMCSPA ranged 260-466 mt in May, 196-513 mt in June, and 91-198 mt in July. The biomass

  3. Investigations of atmospheric dynamics using a CW Doppler sounder array

    NASA Technical Reports Server (NTRS)

    Rao, G. L.

    1974-01-01

    A three-dimensional CW Doppler sounding system currently under operation at the NASA-Marshall Space Flight Center, Alabama is described. The properties of the neutral atmosphere are discussed along with the theory of Doppler sounding technique. Methods of data analyses used to investigate the dynamical phenomena at the ionospheric heights are presented and suggestions for future investigations provided.

  4. The Behm Acoustic Sounder for Airplanes with Reference to Its Accuracy

    NASA Technical Reports Server (NTRS)

    Schreiber, Ernest

    1930-01-01

    Relative altimetry is of great importance for increasing the safety in aerial transportation, because it makes possible safe flying at night, by poor visibility, and when landing. Among the instruments of this type is the Behm sounder, which operates on an acoustic principle. Acoustic altimetry in general and the Behn sounder, in particular, are covered in this report.

  5. All Ionospheres are not Alike: Reports from other Planets

    NASA Technical Reports Server (NTRS)

    Nagy, Andrew F.; Cravens, Thomas E.; Waite, H. J., Jr.

    1995-01-01

    Our understanding of planetary ionospheres made some progress during the last four years. Most of this progress was due to new and/or improved theoretical models, although some new data were also obtained by direct and remote sensing observations. The very basic processes such as ionization, chemical transformations and diffusive as well as convective transports are analogous in all ionospheres; the major differences are the result of factors such as different neutral atmospheres, intrinsic magnetic field strength, distance from the Sun, etc. Improving our understanding of any of the ionospheres in our solar system helps in elucidating the controlling physical and chemical processes in all of them. New measurements are needed to provide new impetus, as well as guidance, in advancing our understanding and we look forward to such information in the years ahead.

  6. 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.

  7. Ionospherically reflected proton whistlers

    NASA Astrophysics Data System (ADS)

    Vavilov, D. I.; Shklyar, D. R.

    2014-12-01

    We present experimental observations and detailed investigation of the variety of proton whistlers that includes transequatorial and ionospherically reflected proton whistlers. The latter have previously been indicated from numerical modeling of spectrograms. The study is based on six-component ELF wave data from the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) satellite which permits to obtain not only spectrograms displaying the power spectral density but also such wave properties as the polarization, wave normal angle, wave refractive index, and normalized parallel component of the Poynting vector. The explanation of various types of proton whistlers is based on the properties of ion cyclotron wave propagation in a multicomponent magnetoplasma, with special consideration of the effect of ion hybrid resonance reflection. Analysis of experimental data is supplemented by numerical modeling of spectrograms that reproduces the main features of experimental ones. As a self-contained result, we provide conclusive experimental evidences that the region illuminated by a lightning stroke in the Earth-ionosphere waveguide may spread over a distance of 4000 km in both hemispheres.

  8. Channel alignment and radiometry in hyperspectral atmospheric infrared sounders

    NASA Technical Reports Server (NTRS)

    Elliott, Denis A.; Aumanna, H. H.; Pagano, Thomas S.; Overoye, Kenneth R.; Schindler, Rudolf A.

    2005-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyper-spectral infrared sounder which covers the 3.7 to 15,4 micron region with 2378 spectral channels. The AIRS instrument specification called for spatial co-registration of all channels to better than 2% of the field of view. Pre-launch testing confirmed that this requirement was met, since the standard deviations in the centroids was about 1% of the 13.5 km IFOV in scan and 3% in track. Detailed analysis of global AIRS data show that the typical scene gradient in 10 micron window channels is about I .3K/km rms. The way these gradients, which are predominantly caused by clouds, manifest themselves in the data depends on the details of the instrument design and the way the spectral channels are used in the data analysis, AIRS temperature and moisture retrievals use 328 of the 2378 channels from 17 independent arrays. As a result, the effect of the boresight misalignment averages to zero mean. Any increase in the effective noise is less than 0.2K. Also, there is no discernable performance degradation of products at the 45 km spatial resolution in the presence of partially cloudy scenes with up to 80% cloudiness. Single pixel radiometric differences between channels with boresight alignment differences can be appreciable and can affect scientific investigations on a single 15km footprint scale, particularly near coastlines, thunderstorms and surface emissivity inhomogeneities.

  9. Requirements for a Moderate-Resolution Infrared Imaging Sounder (MIRIS)

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Aumann, Hartmut H.; Gerber, Andrew J.; Kuai, Le; Gontijo, I.; DeLeon, Berta; Susskind, Joel; Iredell, Lena; Bajpai, Shyam

    2013-01-01

    The high cost of imaging and sounding from space warrants exploration of new methods for obtaining the required information, including changing the spectral band sets, employing new technologies and merging instruments. In some cases we must consider relaxation of the current capability. In others, we expect higher performance. In general our goal is to meet the VIIRS and CrIS requirements while providing the enhanced next generation capabilities: 1) Hyperspectral Imaging in the Vis/NIR bands, 2) High Spatial Resolution Sounding in the Infrared bands. The former will improve the accuracy of ocean color products, aerosols and water vapor, surface vegetation and geology. The latter will enable the high-impact achieved by the current suite of hyperspectral infrared sounders to be achieved by the next generation high resolution forecast models. We examine the spectral, spatial and radiometric requirements for a next generation system and technologies that can be applied from the available inventory within government and industry. A two-band grating spectrometer instrument called the Moderate-resolution Infrared Imaging Sounder (MIRIS) is conceived that, when used with the planned NASA PACE Ocean Color Instrument (OCI) will meet the vast majority of CrIS and VIIRS requirements in the all bands and provide the next generation capabilities desired. MIRIS resource requirements are modest and the Technology Readiness Level is high leading to the expectation that the cost and risk of MIRIS will be reasonable.

  10. Requirements for a Moderate-resolution Infrared Imaging Sounder (MIRIS)

    NASA Astrophysics Data System (ADS)

    Pagano, Thomas S.; Aumann, Hartmut H.; Gerber, Andrew J.; Kuai, Le; Gontijo, I.; DeLeon, Berta; Susskind, Joel; Iredell, Lena; Bajpai, Shyam

    2013-09-01

    The high cost of imaging and sounding from space warrants exploration of new methods for obtaining the required information, including changing the spectral band sets, employing new technologies and merging instruments. In some cases we must consider relaxation of the current capability. In others, we expect higher performance. In general our goal is to meet the VIIRS and CrIS requirements while providing the enhanced next generation capabilities: 1) Hyperspectral Imaging in the Vis/NIR bands, 2) High Spatial Resolution Sounding in the Infrared bands. The former will improve the accuracy of ocean color products, aerosols and water vapor, surface vegetation and geology. The latter will enable the high-impact achieved by the current suite of hyperspectral infrared sounders to be achieved by the next generation high resolution forecast models. We examine the spectral, spatial and radiometric requirements for a next generation system and technologies that can be applied from the available inventory within government and industry. A two-band grating spectrometer instrument called the Moderate-resolution Infrared Imaging Sounder (MIRIS) is conceived that, when used with the planned NASA PACE Ocean Color Instrument (OCI) will meet the vast majority of CrIS and VIIRS requirements in the all bands and provide the next generation capabilities desired. MIRIS resource requirements are modest and the Technology Readiness Level is high leading to the expectation that the cost and risk of MIRIS will be reasonable.

  11. Control of the topside Martian ionosphere by crustal magnetic fields

    NASA Astrophysics Data System (ADS)

    Andrews, D. J.; Edberg, N. J. T.; Eriksson, A. I.; Gurnett, D. A.; Morgan, D.; Němec, F.; Opgenoorth, H. J.

    2015-04-01

    We present observations from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument onboard Mars Express of the thermal electron plasma density of the Martian ionosphere and investigate the extent to which it is influenced by the presence of Mars's remnant crustal magnetic fields. We use locally measured electron densities, derived when MARSIS is operating in active ionospheric sounding (AIS) mode, covering an altitude range from ˜300 km to ˜1200 km. We compare these measured densities to an empirical model of the dayside ionospheric plasma density in this diffusive transport-dominated regime. We show that small spatial-scale departures from the averaged values are strongly correlated with the pattern of the crustal fields. Persistently elevated densities are seen in regions of relatively stronger crustal fields across the whole altitude range. Comparing these results with measurements of the (scalar) magnetic field also obtained by MARSIS/AIS, we characterize the dayside strength of the draped magnetic fields in the same regions. Finally, we provide a revised empirical model of the plasma density in the Martian ionosphere, including parameterizations for both the crustal field-dominated and draping-dominated regimes.

  12. Scale Height variations with solar cycle in the ionosphere of Mars

    NASA Astrophysics Data System (ADS)

    Sanchez-Cano, Beatriz; Lester, Mark; Witasse, Olivier; Milan, Stephen E.; Hall, Benjamin E. S.; Cartacci, Marco; Radicella, Sandro M.; Blelly, Pierre-Louis

    2015-04-01

    The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on board the Mars Express spacecraft has been probing the topside of the ionosphere of Mars since June 2005, covering currently almost one solar cycle. A good knowledge of the behaviour of the ionospheric variability for a whole solar period is essential since the ionosphere is strongly dependent on solar activity. Using part of this dataset, covering the years 2005 - 2012, differences in the shape of the topside electron density profiles have been observed. These variations seem to be linked to changes in the ionospheric temperature due to the solar cycle variation. In particular, Mars' ionospheric response to the extreme solar minimum between end-2007 and end-2009 followed a similar pattern to the response observed in the Earth's ionosphere, despite the large differences related to internal origin of the magnetic field between both planets. Plasma parameters such as the scale height as a function of altitude, the main peak characteristics (altitude, density), the total electron content (TEC), the temperatures, and the ionospheric thermal pressures show variations related to the solar cycle. The main changes in the topside ionosphere are detected during the period of very low solar minimum, when ionospheric cooling occurs. The effect on the scale height is analysed in detail. In contrast, a clear increase of the scale height is observed during the high solar activity period due to enhanced ionospheric heating. The scale height variation during the solar cycle has been empirically modelled. The results have been compared with other datasets such as radio-occultation and retarding potential analyser data from old missions, especially in low solar activity periods (e.g. Mariner 4, Viking 1 and 2 landers), as well as with numerical modelling.

  13. Field Tests of a Gas-Filter Imaging Radiometer for Methane, CH4,: A Prototype for Geostationary Remote Infrared Pollution Sounder, GRIPS

    NASA Astrophysics Data System (ADS)

    Dickerson, R. R.; Fish, C. S.; Brent, L. C.; Burrows, J. P.; Fuentes, J. D.; Gordley, L. L.; Jacob, D. J.; Schoeberl, M. R.; Salawitch, R. J.; Ren, X.; Thompson, A. M.

    2013-12-01

    Gas filter radiometry is a powerful tool for measuring infrared active trace gases. Methane (CH4) is the second most important greenhouse gas and is more potent molecule for molecule than carbon dioxide (CO2). Unconventional natural gas recovery has the potential to show great environmental benefits relative to coal, but only if fugitive leakage is held below 3% and leak rates remain highly uncertain. We present design specifications and initial field/aircraft test results for an imaging remote sensing device to measure column content of methane. The instrument is compared to in situ altitude profiles measured with cavity ring-down. This device is an airborne prototype for the Geostationary Remote Infrared Pollution Sounder, GRIPS, a satellite instrument designed to monitor CH4, CO2, CO, N2O and AOD from geostationary orbit, with capabilities for great advances in air quality and climate research. GRIPS: The Geostationary Remote Infrared Pollution Sounder

  14. Comparison with oblique sounder data of high-latitude HF propagation predictions from RADAR C and AMBCOM computer program

    NASA Astrophysics Data System (ADS)

    Dave, Nikhil

    1988-06-01

    A study is done using two High Frequency (HF) propagation prediction programs - RADAR C and AMBCOM - to determine how well they predict median values of oblique sounder data of maximum observed frequencies (MOF) at high latitudes. The main differences between RADAR C and AMBCOM are the inclusion in the latter of high-latitude ionosphere and auroral absorption models, as well as a more sophisticated and accurate ray-tracing scheme. The data used for comparison are taken for the Winnipeg-Resolute Bay path in the year 1959 and for the Andoya-Ft. Monmouth and Andoya-College paths in 1964. The data for the Winnipeg-Resolute Bay corresponds to high sunspot number, while the others correspond to low sunspot number. Hence, this study provides information on the performance of the two programs for various high-latitude paths at both high and low sunspot number. AMBCOM was found to give generally better agreement with the above data than did RADAR C. Comparison of details of model predictions from the two computer programs for the above data-base is used to form an understanding of this improvement in prediction capability.

  15. Ionospheric climate and weather modeling

    SciTech Connect

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

    1988-03-01

    Simulations of the ionospheric model of Schunk et al. (1986) have been used for climatology and weather modeling. Steady state empirical models were used in the climatology model to provide plasma convection and particle precipitation patterns in the northern high-latitude region. The climatology model also depicts the ionospheric electron density and ion and electron temperatures for solar maximum, winter solstice, and strong geomagnetic activity conditions. The weather model describes the variations of ionospheric features during the solar cycle, seasonal changes, and geomagnetic activity. Prospects for future modeling are considered. 23 references.

  16. The Ionosphere and Ocean Altimetry

    NASA Technical Reports Server (NTRS)

    Lindqwister, Ulf J.

    1999-01-01

    The accuracy of satellite-based single-frequency radar ocean altimeters benefits from calibration of the total electron content (TEC) of the ionosphere below the satellite. Data from the global network of Global Positioning System (GPS) receivers provides timely, continuous, and globally well-distributed measurements of ionospheric electron content. We have created a daily automated process called Daily Global Ionospheric Map (Daily-GIM) whose primary purpose is to use global GPS data to provide ionospheric calibration data for the Geosat Follow-On (GFO) ocean altimeter. This process also produces an hourly time-series of global maps of the electron content of the ionosphere. This system is designed to deliver "quick-look" ionospheric calibrations within 24 hours with 90+% reliability and with a root-mean-square accuracy of 2 cm at 13.6 GHz. In addition we produce a second product within 72 hours which takes advantage of additional GPS data which were not available in time for the first process. The diagram shows an example of a comparison between TEC data from the Topographic Experiment (TOPEX) ocean altimeter and Daily-GIM. TEC are displayed in TEC units, TECU, where 5 TECU is 1 cm at 13.6 GHz. Data from a single TOPEX track is shown. Also shown is the Bent climatological model TEC for the track. Although the GFO satellite is not yet in its operational mode, we have been running Daily-GIM reliably (much better than 90%) with better than 2-cm accuracy (based on comparisons against TOPEX) for several months. When timely ephemeris files for the European Remote Sensing Satellite 2 (ERS-2) are available, daily ERS-2 altimeter ionospheric calibration files are produced. When GFO ephemeris files are made available to us, we produce GFO ionosphere calibration files. Users of these GFO ionosphere calibration files find they are a great improvement over the alternative International Reference Ionosphere 1995 (IRI-95) climatological model. In addition, the TOPEX orbit

  17. Evidence of Convective Redistribution of Carbon Monoxide in Aura Tropospheric Emission Sounder (TES) and Microwave Limb Sounder (MLS) Observations

    NASA Technical Reports Server (NTRS)

    Manyin, Michael; Douglass, Anne; Schoeberl, Mark

    2010-01-01

    Vertical convective transport is a key element of the tropospheric circulation. Convection lofts air from the boundary layer into the free troposphere, allowing surface emissions to travel much further, and altering the rate of chemical processes such as ozone production. This study uses satellite observations to focus on the convective transport of CO from the boundary layer to the mid and upper troposphere. Our hypothesis is that strong convection associated with high rain rate regions leads to a correlation between mid level and upper level CO amounts. We first test this hypothesis using the Global Modeling Initiative (GMI) chemistry and transport model. We find the correlation is robust and increases as the precipitation rate (the strength of convection) increases. We next examine three years of CO profiles from the Tropospheric Emission Sounder (TES) and Microwave Limb Sounder (MLS) instruments aboard EOS Aura. Rain rates are taken from the Tropical Rainfall Measuring Mission (TRMM) 3B-42 multi-satellite product. Again we find a correlation between mid-level and upper tropospheric CO, which increases with rain rate. Our result shows the critical importance of tropical convection in coupling vertical levels of the troposphere in the transport of trace gases. The effect is seen most clearly in strong convective regions such as the Inter-tropical Convergence Zone.

  18. Ionospheric plasma drift and structure studies at high and mid-latitudes. Volume 1. Final report, October 1990-October 1993

    SciTech Connect

    Reinisch, B.W.; Scali, J.L.; Dozois, C.; Crowley, G.

    1993-12-01

    Ground-based observations of the high latitude ionosphere with Digisonde sounders at Quaanaaq, Sondrestrom, Goose Bay, Argentina and Millstone Hill provide a description of the patch structure and the convection pattern in the polar cap. Correlation analysis of observed F-region plasma drifts with the orientation of the interplanetary magnetic field (measured by IMP8) lead to a new technique of deducing the signs of Bz and By from the measured drifts. Real time calculation of the plasma drift was successfully introduced at one of the Digisonde stations (Sondrestrom) providing the possibility of determining the IMF components in real time. Analysis of mid-latitude trough observation shows large westward velocities in the trough region. Digisonde data from Quaanaaq and DMSP F8 and F9 satellite data showed the development of the ionospheric polar hole.

  19. Radar Studies of Ionospheric Plasma Irregularities

    NASA Astrophysics Data System (ADS)

    Rao, P. B.

    2006-11-01

    High power high resolution VHF radars have proven to be powerful diagnostics to study ionospheric plasma irregularities, a space weather phenomenon of immense importance in view of its impact on space communication and navigation. The VHF radars at Jicamarca, Peru and Trivandrum, India have contributed greatly over the past four decades in arriving at the current understanding of the basic characteristics of the equatorial spread-F (ESF) and equatorial electrojet (EEJ) irregularities and the underlying plasma instability processes. Recent advances, involving high resolution radar observations of equatorial plasma irregularities, include the detection of supersonic plasma bubbles rising to heights beyond 1000 km, 150 km echoes and kilometric scale waves. The new and more recent developments in plasma irregularity studies came from the middle and upper atmosphere (MU) radar at Shigaraki, Japan and the mesosphere stratosphere troposphere (MST) radar at Gadanki, India. The new types of plasma irregularity structures observed by this mid- and low latitude VHF radars cover the well known quasi- periodic (QP) waves, tidal ion layers, kilometric scale waves and structures in the collision dominated lower E region. The paper presents an overview on the recent advances in the radar technique and the above mentioned new developments in observation and theory of the equatorial and low latitude ionospheric plasma irregularities.

  20. TEC disturbances during major Sudden Stratospheric Warmings in the mid-latitude ionosphere.

    NASA Astrophysics Data System (ADS)

    Polyakova, Anna; Voeykov, Sergey; Chernigovskaya, Marina; Perevalova, Natalia

    Using total electron content (TEC) global ionospheric maps, dual-frequency GPS receivers TEC data and MLS (Microwave Limb Sounder, EOS Aura) atmospheric temperature data the ionospheric disturbances during the strong sudden stratospheric warmings (SSWs) of 2008/2009 and 2012/2013 winters are investigated in Russia's Asia region. It is established that during the SSW maximum the midday TEC decrease and the night/morning TEC increase compared to quiet days are observed in the mid-latitude ionosphere. As a result it caused the decrease of the diurnal TEC variations amplitude of about two times in comparison with the undisturbed level. The analysis of TEC deviations from the background level during the SSWs has shown that deviations dynamics vary depending on the observation point position. Negative deviations of TEC are registered in the ionosphere above the region of maximum stratosphere heating (the region of the stratospheric circulation change) as well as above the anticyclone. On the contrary, TEC values increase compared to the quiet day's values above the stratosphere cyclone. It is shown that during maximum phase of a warming, and within several days after it the amplification of wave TEC variations intensity with periods of up to 60 min is registered in ionosphere. The indicated effects may be attributed to the vertical transfer of molecular gas from a stratospheric heating region to the thermosphere as well as to the increase in activity of planetary and gravity waves which is usually observed during strong SSWs. The study is supported by the RF President Grant of Public Support for RF Leading Scientific Schools (NSh-2942.2014.5), the RF President Grant No. MK-3771.2012.5 and RFBR Grant No. 12-05-00865_а.

  1. Performance status of the Atmospheric Infrared Sounder ten years after launch

    NASA Astrophysics Data System (ADS)

    Pagano, Thomas S.; Broberg, Steve; Aumann, Hartmut H.; Elliott, Denis; Manning, Evan; Strow, Larrabee

    2012-11-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the EOS Aqua Spacecraft, launched on May 4, 2002. AIRS has 2378 infrared channels ranging from 3.7 μm to 15.4 μm and a 13.5 km footprint at nadir. The AIRS is a "facility" instrument developed by NASA as an experimental demonstration of advanced technology for remote sensing and the benefits of high resolution infrared spectra to science investigations. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy on a global scale, as well as water vapor profiles and trace gas amounts for CO2, CO, SO2, O3 and CH4. AIRS data are used for weather forecasting, climate process studies and validating climate models. The AIRS instrument has far exceeded its required design life of 5 years, with over 10 years of operations as of September 2012. While the instrument has performed exceptionally well, with little signs of wear, the AIRS Project continues to monitor and maintain the health of AIRS, characterize its behavior and improve performance where possible. Radiometric stability has been monitored and trending shows better than 16 mK/year stability. Spectral calibration stability is better than 1 ppm/year, and a new gain table was recently uploaded to recover 100 significantly degraded or dead channels by switching to their redundant counterpart. At this time we expect the AIRS to continue to perform well for the next decade.

  2. GeoSTAR: a geostationary microwave sounder for the future

    NASA Astrophysics Data System (ADS)

    Lambrigtsen, B. H.; Brown, S. T.; Dinardo, S. J.; Gaier, T. C.; Kangaslahti, P. P.; Tanner, A. B.

    2007-09-01

    The Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) is a new Earth remote sensing instrument concept that has been under development at the Jet Propulsion Laboratory. First conceived in 1998 as a NASA New Millennium Program mission and subsequently developed in 2003-2006 as a proof-of-concept prototype under the NASA Instrument Incubator Program, it is intended to fill a serious gap in our Earth remote sensing capabilities - namely the lack of a microwave atmospheric sounder in geostationary orbit. The importance of such observations have been recognized by the National Academy of Sciences National Research Council, which recently released its report on a "Decadal Survey" of NASA Earth Science activities. One of the recommended missions for the next decade is a geostationary microwave sounder. GeoSTAR is well positioned to meet the requirements of such a mission, and because of the substantial investment NASA has already made in GeoSTAR technology development, this concept is fast approaching the necessary maturity for implementation in the next decade. NOAA is also keenly interested in GeoSTAR as a potential payload on its next series of geostationary weather satellites, the GOES-R series. GeoSTAR, with its ability to map out the three-dimensional structure of temperature, water vapor, clouds, precipitation and convective parameters on a continual basis, will significantly enhance our ability to observe hurricanes and other severe storms. In addition, with performance matching that of current and next generation of low-earth-orbiting microwave sounders, GeoSTAR will also provide observations important to the study of the hydrologic cycle, atmospheric processes and climate variability and trends. In particular, with GeoSTAR it will be possible to fully resolve the diurnal cycle. We discuss the GeoSTAR concept and basic design, the performance of the prototype, and a number of science applications that will be possible with GeoSTAR. The work reported

  3. Geo-STAR: A Geostationary Microwave Sounder for the Future

    NASA Technical Reports Server (NTRS)

    Lambrigtsen, Bjorn H.; Brown, S. T.; Dinardo, S. J.; Gaier, T. C.; Kangaslahti, P. P.; Tanner, A. B.

    2007-01-01

    The Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) is a new Earth remote sensing instrument concept that has been under development at the Jet Propulsion Laboratory. First conceived in 1998 as a NASA New Millennium Program mission and subsequently developed in 2003-2006 as a proof-of-concept prototype under the NASA Instrument Incubator Program, it is intended to fill a serious gap in our Earth remote sensing capabilities - namely the lack of a microwave atmospheric sounder in geostationary orbit. The importance of such observations have been recognized by the National Academy of Sciences National Research Council, which recently released its report on a 'Decadal Survey' of NASA Earth Science activities1. One of the recommended missions for the next decade is a geostationary microwave sounder. GeoSTAR is well positioned to meet the requirements of such a mission, and because of the substantial investment NASA has already made in GeoSTAR technology development, this concept is fast approaching the necessary maturity for implementation in the next decade. NOAA is also keenly interested in GeoSTAR as a potential payload on its next series of geostationary weather satellites, the GOES-R series. GeoSTAR, with its ability to map out the three-dimensional structure of temperature, water vapor, clouds, precipitation and convective parameters on a continual basis, will significantly enhance our ability to observe hurricanes and other severe storms. In addition, with performance matching that of current and next generation of low-earth-orbiting microwave sounders, GeoSTAR will also provide observations important to the study of the hydrologic cycle, atmospheric processes and climate variability and trends. In particular, with GeoSTAR it will be possible to fully resolve the diurnal cycle. We discuss the GeoSTAR concept and basic design, the performance of the prototype, and a number of science applications that will be possible with GeoSTAR. The work reported

  4. 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.

  5. Magnetosphere, ionosphere and atmosphere interactions

    NASA Technical Reports Server (NTRS)

    Banks, P. M.

    1979-01-01

    In the present review, the general nature of the earth's space environment is discussed with particular reference to the physical processes which link the magnetosphere, the ionosphere, and the upper atmosphere. Recent theoretical and experimental research has revealed the existence of subtle couplings which closely link the electrical and mass properties of these regions. Some of these couplings have been known for many years. Recent discoveries include such couplings as the formation of the plasmasphere through the mutual action of convective electric fields and ionospheric plasma flows. However, there is still insufficient information to define accurately the basic processes associated with space plasma dynamics when cool thermal plasma of ionospheric origin interacts with the neutral atmosphere, the energetic plasma of the ionosphere, and the solar wind. The primary objective of the discussion is to provide a general introduction to the more challenging processes as they are presently known.

  6. A new global ionospheric model

    NASA Technical Reports Server (NTRS)

    Yip, K. W.; Vonroos, O. H.

    1975-01-01

    A new global ionospheric model was successfully implemented. The daytime portion of this model provides one-way ionospheric range corrections that compare favorably with those derived from the Mariner Venus/Mercury S- and X-band dual frequency Doppler data. For elevation angles, gamma higher than 30 deg and solar zenith angle less than 80 deg, this model provides calibrations accurate to a few centimeters. The calibrations provided by the nighttime model are also very reasonable. It is interesting to note that the daytime ionospheric calibrations derived from the current calibration scheme, DIEN/TIEN, are fairly close to those given by the new global model, especially in the temporal variations and thus the Doppler effects. The comparison between the nighttime model and DIEN/TIEN was based on the one-way ionospheric range corrections for three passes near the Mariner 9 encounter with Mars in 1971. They can differ by over 30%.

  7. The International Reference Ionosphere: Model Update 2016

    NASA Astrophysics Data System (ADS)

    Bilitza, Dieter; Altadill, David; Reinisch, Bodo; Galkin, Ivan; Shubin, Valentin; Truhlik, Vladimir

    2016-04-01

    The International Reference Ionosphere (IRI) is recognized as the official standard for the ionosphere (COSPAR, URSI, ISO) and is widely used for a multitude of different applications as evidenced by the many papers in science and engineering journals that acknowledge the use of IRI (e.g., about 11% of all Radio Science papers each year). One of the shortcomings of the model has been the dependence of the F2 peak height modeling on the propagation factor M(3000)F2. With the 2016 version of IRI, two new models will be introduced for hmF2 that were developed directly based on hmF2 measurements by ionosondes [Altadill et al., 2013] and by COSMIC radio occultation [Shubin, 2015], respectively. In addition IRI-2016 will include an improved representation of the ionosphere during the very low solar activities that were reached during the last solar minimum in 2008/2009. This presentation will review these and other improvements that are being implemented with the 2016 version of the IRI model. We will also discuss recent IRI workshops and their findings and results. One of the most exciting new projects is the development of the Real-Time IRI [Galkin et al., 2012]. We will discuss the current status and plans for the future. Altadill, D., S. Magdaleno, J.M. Torta, E. Blanch (2013), Global empirical models of the density peak height and of the equivalent scale height for quiet conditions, Advances in Space Research 52, 1756-1769, doi:10.1016/j.asr.2012.11.018. Galkin, I.A., B.W. Reinisch, X. Huang, and D. Bilitza (2012), Assimilation of GIRO Data into a Real-Time IRI, Radio Science, 47, RS0L07, doi:10.1029/2011RS004952. Shubin V.N. (2015), Global median model of the F2-layer peak height based on ionospheric radio-occultation and ground-based Digisonde observations, Advances in Space Research 56, 916-928, doi:10.1016/j.asr.2015.05.029.

  8. 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.

  9. Satellite Sounder Data Assimilation for Improving Alaska Region Weather Forecast

    NASA Technical Reports Server (NTRS)

    Zhu, Jiang; Stevens, E.; Zavodsky, B. T.; Zhang, X.; Heinrichs, T.; Broderson, D.

    2014-01-01

    Data assimilation has been demonstrated very useful in improving both global and regional numerical weather prediction. Alaska has very coarser surface observation sites. On the other hand, it gets much more satellite overpass than lower 48 states. How to utilize satellite data to improve numerical prediction is one of hot topics among weather forecast community in Alaska. The Geographic Information Network of Alaska (GINA) at University of Alaska is conducting study on satellite data assimilation for WRF model. AIRS/CRIS sounder profile data are used to assimilate the initial condition for the customized regional WRF model (GINA-WRF model). Normalized standard deviation, RMSE, and correlation statistic analysis methods are applied to analyze one case of 48 hours forecasts and one month of 24-hour forecasts in order to evaluate the improvement of regional numerical model from Data assimilation. The final goal of the research is to provide improved real-time short-time forecast for Alaska regions.

  10. Determination of cloud parameters from infrared sounder data

    NASA Technical Reports Server (NTRS)

    Yeh, H.-Y. M.

    1984-01-01

    The World Climate Research Programme (WCRP) plan is concerned with the need to develop a uniform global cloud climatology as part of a broad research program on climate processes. The International Satellite Cloud Climatology Project (ISCCP) has been approved as the first project of the WCRP. The ISCCP has the basic objective to collect and analyze satellite radiance data to infer the global distribution of cloud radiative properties in order to improve the modeling of cloud effects on climate. Research is conducted to explore an algorithm for retrieving cloud properties by utilizing the available infrared sounder data from polar-orbiting satellites. A numerical method is developed for computing cloud top heights, amount, and emissivity on the basis of a parameterized infrared radiative transfer equation for cloudy atmospheres. Theoretical studies were carried out by considering a synthetic atmosphere.

  11. Mechanical Description of the Mars Climate Sounder Instrument

    NASA Technical Reports Server (NTRS)

    Jau, Bruno M.

    2008-01-01

    This paper introduces the Mars Climate Sounder (MCS) Instrument of the Mars Reconnaissance Orbiter (MRO) spacecraft. The instrument scans the Martian atmosphere almost continuously to systematically acquire weather and climate observations over time. Its primary components are an optical bench that houses dual telescopes with a total of nine channels for visible and infrared sensing, and a two axis gimbal that provides pointing capabilities. Both rotating joints consist of an integrated actuator with a hybrid planetary/harmonic transmission and a twist cap section that enables the electrical wiring to pass through the rotating joint. Micro stepping is used to reduce spacecraft disturbance torques to acceptable levels while driving the stepper motors. To ensure survivability over its four year life span, suitable mechanical components, lubrication, and an active temperature control system were incorporated. Some life test results and lessons learned are provided to serve as design guidelines for actuator parts and flex cables.

  12. The Atmospheric Infrared Sounder (AIRS) on the Earth Observing System

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Pagano, Thomas S.; Strow, Larrabee

    2001-01-01

    AIRS, the Atmospheric Infrared Sounder on the EOS-Aqua, produces global high precision spectra from 3.7 - 15.4 micron with spectral resolving power mu/delta mu = 1200 twice each day from 708 km orbital altitude. AIRS is the first hyperspectral infrared spectrometer designed to support NOAA/NCEP's operational requirements for medium range weather forecasting during its nominal 7 year lifetime. AIRS, together with the AMSU and HSB microwave radiometers, will achieve global retrieval accuracy of better then 1K rms in the lower troposphere under clear and partly cloudy condition. Based on the excellent radiometric and spectral performance demonstrated during the pre-launch testing, the assimilation of AIRS data into the forecast model is expected to result in major forecast improvements. Launch of AIRS on the EOS AQUA is scheduled for May 2001.

  13. A submillimeter sounder for the Titan Saturn System Mission (TSSM)

    NASA Astrophysics Data System (ADS)

    Lellouch, E.; Vinatier, S.; Moreno, R.; Allen, M.; Gulkis, S.; Hartogh, P.; Mehdi, I.; Maestrini, A.; Krieg, J.-M.

    2008-09-01

    A submillimeter sounder (SMS) onboard the TSSM mission and operating mostly in limb viewing is a powerful instrument to study Titan's atmosphere from ~50 to 1200 km, and especially the largely unexplored "agnostophere" from 500 to 1000 km. Unique capabilities of such an instrument include (i) measurement of temperature field up to 1200 km, using rotational lines of CH4, CO, and HCN (ii) direct, absolute and accurate wind measurements from Doppler shifts (iii) high sensitivity to trace minor compounds, particularly nitriles and rare isotope species. Altogether, SMS can provide a new characterization of the couplings between stratospheric/mesospheric chemistry and dynamics, and of their relationships with the complex thermospheric chemistry observed by Cassini. At Enceladus, SMS can provide detailed measurements of temperature, composition and gas plume dynamics.

  14. Stratospheric CH3CN from the UARS Microwave Limb Sounder

    NASA Astrophysics Data System (ADS)

    Livesey, Nathaniel J.; Waters, Joe W.; Khosravi, Rashid; Brasseur, Guy P.; Tyndall, Geoffrey S.; Read, William G.

    CH3CN in the stratosphere has been measured by the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS), providing the first global CH3CN dataset. The MLS observations are in broad agreement with past high and midlatitude observations of CH3CN, although concentrations are a little larger than previously observed. In the tropics, where CH3CN has not up to now been measured, a persistent ‘peak’ in the profiles is seen around 22 hPa, which may be evidence of a tropical stratospheric CH3CN source. Comparisons are made with the NCAR SOCRATES model, including runs having an artificial tropical stratospheric CH3CN source.

  15. Altitude Variation of the Plasmapause Signature in the Main Ionospheric Trough

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Benson, Robert F.; Webb, Phillip A.; Truhlik, Vladimir; Bilitza, Dieter

    2009-01-01

    The projection of the plasmapause magnetic-field lines to low altitudes, where the light-ion chemistry is dominated by O(+), tends to occur near the minimum electron density in the main (midlatitude) electron density trough at night. With increasing attitude in the trough, where H(+) emerges as the dominant iota on the low-latitude boundary, we have found cases where the plasmapause field lines are located on the sharp low-Latitude side of the trough as expected if this topside ionosphere H(+) distribution varies in step with the plasmapause gradient in the distant plasmasphere. These conclusions are based on near-equatorial crossings of the plasmapause (corresponding to the steep gradient in the dominant species H(+) by the Explorer-45 satellite as determined from electric-field measurements by Maynard and Cauffman in the early 1970s and ISIS-2 ionospheric topside-sounder measurements. The former data have now been converted to digital form and made available at http://nssdcftp.gsfc.nasa.gov. The latter provide samples of nearly coincident observations of ionospheric main trough crossings near the same magnetic-field lines of the Explorer 45-determined equatorial plasmapause. The ISIS-2 vertical electron density profiles are used to infer where the F-region transitions from an O(+) to a H(+) dominated plasma through the main trough boundaries.

  16. Validation of the Atmospheric Infrared Sounder (AIRS) version 5 land surface emissivity product over the Namib and Kalahari deserts

    NASA Astrophysics Data System (ADS)

    Hulley, Glynn C.; Hook, Simon J.; Manning, Evan; Lee, Sung-Yung; Fetzer, Eric

    2009-10-01

    Hyperspectral infrared sounders require accurate knowledge of the land surface emissivity (LSE) to retrieve important climate variables such as surface temperature, air temperature, and total water vapor from space. This study provides a method for validating and assessing the Atmospheric Infrared Sounder (AIRS) version 5 LSE product using high-spatial resolution data (90 m) from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) which has five bands in the thermal infrared region (8-12 μm, 1250-833 cm-1) and high-spectral resolution laboratory measurements of sand samples collected over the Namib and Kalahari deserts in southern Africa. Results indicate that the mean, absolute daytime LSE difference between AIRS and the laboratory results for six wavelengths in window regions between 3.9 and 11.4 μm (2564-877 cm-1) was 2.3% over the Namib and 0.70% over the Kalahari, while the mean difference with ASTER was 2.3% over the Namib and 2.26% over the Kalahari for four bands between 8 and 12 μm. Systematic modeling and surface dependent AIRS LSE retrieval errors such as large discrepancies between day and nighttime shortwave LSE (up to 15%), unphysical values (LSE >1), and large daytime temporal variations in the shortwave region (up to 30%) are further discussed.

  17. Cross-Track Infrared Sounder Science Data Record Pre-launch Calibration and On-Orbit Validation Plans

    NASA Astrophysics Data System (ADS)

    Hagan, D. E.; Bingham, G. E.; Predina, J.; Gu, D.; Sabet-Peyman, F.; Wang, C.; de Amici, G.; Plonski, M.; Farrow, S. V.; Hohn, J.; Esplin, M.; Zavyalov, V.; Fish, C. S.; Glumb, R.; Wells, S.; Suwinski, L.; Strong, J.; Behrens, C.; Kilcoyne, H.; Feeley, J.; Kratz, G.; Tremblay, D. A.

    2009-12-01

    The Cross-Track Infrared Sounder (CrIS) together with the Advanced Technology Microwave Sounder will provide retrievals of atmospheric moisture and temperature profiles for the National Polar-orbiting Operational Environmental Satellite System (NPOESS). The NPOESS is the next generation of low Earth orbiting weather and climate satellites managed by the tri-agency Integrated Program Office, which includes the Department of Commerce, Department of Defense and the National Aeronautics and Space Administration. The CrIS is a Fourier-transform Michelson interferometer covering the spectral range of 3.9 to 15.4 microns (650 to 2550 wavenumbers) developed by ITT under contract to Northrop Grumman Aerospace Systems. The first deployment of the CrIS (Flight Model 1) is scheduled for 2010 on the NPOESS Preparatory Project (NPP) satellite, an early instrument risk reduction component of the NPOESS mission. The analysis and data results from comprehensive TVAC testing of the CrIS FM1 sensor demonstrate a very accurate radiometric and spectral calibration system. We describe instrument performance parameters, and the end-to-end plans and analysis tools for on-orbit verification of sensor characteristics and validation of the SDR radiance products.

  18. How Strong is the Case for Geostationary Hyperspectral Sounders?

    NASA Astrophysics Data System (ADS)

    Kirk-Davidoff, D. B.; Liu, Z.; Jensen, S.; Housley, E.

    2014-12-01

    The NASA GIFTS program designed and constructed a flight-ready hyperspectral infrared sounder for geostationary orbit. Efforts are now underway to launch a constellation of similar instruments. Salient characteristics included 4 km spatial resolution at nadir and 0.6 cm-1 spectral resolution in two infrared bands. Observing system experiments have demonstrated the success of assimilated hyperspectral infrared radiances from IASI and AIRS in improving weather forecast skill. These results provide circumstantial evidence that additional observations at higher spatial and temporal resolution would likely improve forecast skill further. However, there is only limited work investigating the magnitude of this skill improvement in the literature. Here we present a systematic program to quantify the additional skill of a constellation of geostationary hyperspectral sounders through observing system simulation experiments (OSSEs) using the WRF model and the WRFDA data assimilation system. The OSSEs will focus first on high-impact events, such as the forecast for Typhoon Haiyun, but will also address quotidian synoptic forecast skill. The focus will be on short-term forecast skill (<24 hours lead time), in accord with WRF's mesoscale design, and with the view that high time frequency observations are likely to make the biggest impact on the skill of short-range forecasts. The experiments will use as their starting point the full existing observational suite, so that additionality can be addressed, but will also consider contingencies, such as the loss of particular elements of the existing system, as well as the degree to which a stand-alone system of hyperspectral sounds would be able to successfully initialize a regional forecast model. A variety of settings, tropical and extratropical, marine and continental will be considered.

  19. A New Paradigm for Ionosphere-Thermosphere-Mesosphere Physics

    NASA Astrophysics Data System (ADS)

    Fuller-Rowell, Tim

    2015-04-01

    The ionosphere-thermosphere-mesosphere system is predominantly a neutral atmosphere domain with a fairly small fraction, less than 1%, that is ionized, similar in some ways to the chromosphere. Neutral dynamics and composition therefore play an important role in influencing and controlling the ionospheric plasma density and creating structure. Neutral thermospheric dynamics is driven from both above and below. Absorption of solar extreme ultraviolet radiation drives a global circulation, and magnetosphere/ionosphere plasma convection can accelerate neutral winds in excess of 1 km/s through collisions, and raise gas temperature by hundreds of degrees Kelvin by frictional dissipation. During extreme events these solar and magnetospheric sources dominate the ITM system, and understanding the plethora of physical processes that ensue has been the focus for more than 50 years. However, the bulk of solar energy reaching Earth penetrates well into the lower atmosphere and to the surface. Even if only a small fraction of this large energy reservoir can reach above 100 km it can have a significant impact on the ITM system and its variability. The main dynamic coupling and transfer of energy from below is largely through atmospheric waves, particularly tides (waves with harmonics of the 24 hour solar day), and gravity waves from the multitude of sources in the lower atmosphere. We now appreciate that dynamical changes and warmings in the stratosphere from changes in planetary wave activity can lead to a 50% change in electron content in the ionosphere, and which can actually be forecast days in advance. Tropospheric convection over continental landmass imprints a longitude structure on the ionosphere. Convective adjustment, extreme weather, wind shear, airflow over mountains, are some of the many sources of gravity waves activity that can grow in amplitude as they propagate into the thermosphere where they modulate and tilt the ionosphere. The ITM system is dynamic and

  20. Ionospheric Profiling using GPS/MET Data

    NASA Technical Reports Server (NTRS)

    Hajj, George; Romans, Larry

    1996-01-01

    A report on ionospheric profiling using GPS and MET data is presented. A description of the GPS occultation technique, some examples of GPS/MET data products, the data processing system and a preliminary validation of ionospheric profiles is discussed.

  1. Distribution functions and statistical parameters that may be used to characterize limb sounders gravity wave climatologies in the stratosphere

    NASA Astrophysics Data System (ADS)

    Alexander, P.; Luna, D.; de la Torre, A.; Schmidt, T.

    2015-08-01

    The number of gravity wave (GW) activity climatologies in the stratosphere started to increase more than 10 years ago since the appearance of large amounts of limb and nadir satellite sounders data. There have been very few discussions regarding the adequate statistical description of GW activity in terms of a distribution function and its parameters. We put forward the question whether a general statistical functional representation adaptable to the characteristics of GW activity in diverse geographic regions and seasons exists. Here we approach this issue for two different types of limb sounders and in particular we try to find out which parameters may represent at best the climatological features. We study results for a region close to the Patagonian Andes and their prolongation in the Antarctic Peninsula, which is well-known for the generation by topography of intense stratospheric GW, specially during winter and spring. Global Positioning System (GPS) radio occultation (RO) records presently provide over 2000 profiles per day. We used 5 years of COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) mission GPS RO data, which supplied almost 150,000 retrievals for our study. Three different distribution functions have been approached to describe the GW activity climatologies: gaussian, log-normal and gamma. The latter function has not been used in previous work. It has been shown here that it is a competitive option to the log-normal distribution. In addition, its use allows not only to quantify the GW activity level of each climatology in the stratosphere, but also to find out the number of significant modes that essentially determine it. Alternative parameters to the mean like the median may be used to characterize the climatologies. The use of the median may exhibit advantages in cases where the presence of spurious large GW activity measurements are suspected in GPS RO data. The mean is equally suitable to establish GW activity

  2. The impact of atmospheric infrared sounder (AIRS) profiles on short-term weather forecasts

    NASA Astrophysics Data System (ADS)

    Zavodsky, Bradley T.; Chou, Shih-Hung; Jedlovec, Gary; Lapenta, William

    2007-04-01

    The Atmospheric Infrared Sounder (AIRS), together with the Advanced Microwave Sounding Unit (AMSU), represents one of the most advanced space-based atmospheric sounding systems. Aside from monitoring changes in Earth's climate, one of the objectives of AIRS is to provide sounding information with sufficient accuracy such that the assimilation of the new observations, especially in data sparse regions, will lead to an improvement in weather forecasts. The combined AIRS/AMSU system provides radiance measurements used as input to a sophisticated retrieval scheme which has been shown to produce temperature profiles with an accuracy of 1 K over 1 km layers and humidity profiles with accuracy of 10-15% in 2 km layers in both clear and partly cloudy conditions. The retrieval algorithm also provides estimates of the accuracy of the retrieved values at each pressure level, allowing the user to select profiles based on the required error tolerances of the application. The purpose of this paper is to describe a procedure to optimally assimilate high-resolution AIRS profile data in a regional analysis/forecast model. The paper focuses on a U.S. East-Coast cyclone from November 2005. Temperature and moisture profiles-containing information about the quality of each temperature layer-from the prototype version 5.0 Earth Observing System (EOS) science team retrieval algorithm are used in this study. The quality indicators are used to select the highest quality temperature and moisture data for each profile location and pressure level. AIRS data are assimilated into the Weather Research and Forecasting (WRF) numerical weather prediction model using the Advanced Regional Prediction System (ARPS) Data Analysis System (ADAS), to produce near-real-time regional weather forecasts over the continental U.S. The preliminary assessment of the impact of the AIRS profiles will focus on intelligent use of the quality indicators, analysis impact, and forecast verification against rawinsondes

  3. 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

  4. Development and initial assessment of a new land index for microwave humidity sounder cloud detection

    NASA Astrophysics Data System (ADS)

    Qin, Zhengkun; Zou, Xiaolei

    2016-02-01

    This paper describes a new quality control (QC) scheme for microwave humidity sounder (MHS) data assimilation. It consists of a cloud detection step and an O-B (i.e., differences of brightness temperatures between observations and model simulations) check. Over ocean, cloud detection can be carried out based on two MHS window channels and two Advanced Microwave Sounding Unit-A (AMSU-A) window channels, which can be used for obtaining cloud ice water path (IWP) and liquid water path (LWP), respectively. Over land, cloud detection of microwave data becomes much more challenging due to a much larger emission contribution from land surface than that from cloud. The current MHS cloud detection over land employs an O-B based method, which could fail to identify cloudy radiances when there is mismatch between actual clouds and model clouds. In this study, a new MHS observation based index is developed for identifying MHS cloudy radiances over land. The new land index for cloud detection exploits the large variability of brightness temperature observations among MHS channels over different clouds. It is shown that those MHS cloudy radiances that were otherwise missed by the current O-B based QC method can be successfully identified by the new land index. An O-B check can then be employed to the remaining data after cloud detection to remove additional outliers with model simulations deviated greatly from observations. It is shown that MHS channel correlations are significantly reduced by the newly proposed QC scheme.

  5. Data Assimilation and Regional Forecasts Using Atmospheric InfraRed Sounder (AIRS) Profiles

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Bradley; Jedlovec, Gary

    2009-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses, which in turn should lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles with an accuracy comparable to that of radiosondes. The purpose of this paper is to describe a procedure to optimally assimilate AIRS thermodynamic profiles--obtained from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm-into a regional configuration of the Weather Research and Forecasting (WRF) model using WRF-Var. The paper focuses on development of background error covariances for the regional domain and background field type, a methodology for ingesting AIRS profiles as separate over-land and over-water retrievals with different error characteristics, and utilization of level-by-level quality indicators to select only the highest quality data. The assessment of the impact of the AIRS profiles on WRF-Var analyses will focus on intelligent use of the quality indicators, optimized tuning of the WRF-Var, and comparison of analysis soundings to radiosondes. The analyses will be used to conduct a month-long series of regional forecasts over the continental U.S. The long-tern1 impact of AIRS profiles on forecast will be assessed against verifying radiosonde and stage IV precipitation data.

  6. Data Assimilation and Regional Forecasts using Atmospheric InfraRed Sounder (AIRS) Profiles

    NASA Technical Reports Server (NTRS)

    Zabodsky, Brad; Chou, Shih-Hung; Jedlovec, Gary J.

    2009-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses, which in turn should lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which, together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles with an accuracy comparable to that of radionsondes. The purpose of this poster is to describe a procedure to optimally assimilate AIRS thermodynamic profiles, obtained from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm, into a regional configuration of the Weather Research and Forecasting (WRF) model using WRF-Var. The poster focuses on development of background error covariances for the regional domain and background field type, a methodology for ingesting AIRS profiles as separate over-land and over-water retrievals with different error characteristics, and utilization of level-by-level quality indicators to select only the highest quality data. The assessment of the impact of the AIRS profiles on WRF-Var analyses will focus on intelligent use of the quality indicators, optimized tuning of the WRF-Var, and comparison of analysis soundings to radiosondes. The analyses are used to conduct a month-long series of regional forecasts over the continental U.S. The long-term impact of AIRS profiles on forecast will be assessed against NAM analyses and stage IV precipitation data.

  7. Airborne Deployment and Calibration of Microwave Atmospheric Sounder on 6U CubeSat

    NASA Astrophysics Data System (ADS)

    Padmanabhan, S.; Brown, S. T.; Lim, B.; Kangaslahti, P.; Russell, D.; Stachnik, R. A.

    2015-12-01

    To accurately predict how the distribution of extreme events may change in the future we need to understand the mechanisms that influence such events in our current climate. Our current observing system is not well-suited for observing extreme events globally due to the sparse sampling and in-homogeneity of ground-based in-situ observations and the infrequent revisit time of satellite observations. Observations of weather extremes, such as extreme precipitation events, temperature extremes, tropical and extra-tropical cyclones among others, with temporal resolution on the order of minutes and spatial resolution on the order of few kms (<10 kms), are required for improved forecasting of extreme weather events. We envision a suite of low-cost passive microwave sounding and imaging sensors on CubeSats that would work in concert with traditional flagship observational systems, such as those manifested on large environmental satellites (i.e. JPSS,WSF,GCOM-W), to monitor weather extremes. A 118/183 GHz sensor would enable observations of temperature and precipitation extremes over land and ocean as well as tropical and extra-tropical cyclones. This proposed project would enable low cost, compact radiometer instrumentation at 118 and 183 GHz that would fit in a 6U Cubesat with the objective of mass-producing this design to enable a suite of small satellites to image the key geophysical parameters needed to improve prediction of extreme weather events. We take advantage of past and current technology developments at JPL viz. HAMSR (High Altitude Microwave Scanning Radiometer), Advanced Component Technology (ACT'08) to enable low-mass, low-power high frequency airborne radiometers. In this paper, we will describe the design and implementation of the 118 GHz temperature sounder and 183 GHz humidity sounder on the 6U CubeSat. In addition, we will discuss the maiden airborne deployment of the instrument during the Plain Elevated Convection at Night (PECAN) experiment. The

  8. Remote Sensing of Atmospheric Climate Parameters from the Atmospheric Infrared Sounder

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Chahine, Moustafa T.; Aumann, Hartmut H.; Tian, Baijun; Lee, Sung-Yung; Olsen, Ed; Lambrigtsen, Bjorn; Fetzer, Eric; Irion, F. W.; McMillan, Wallace; Strow, Larrabee; Fu, Xiouhua; Barnet, Chris; Goldberg, Mitch; Susskind, Joel; Blaisdell, John

    2006-01-01

    This paper presents the standard and research products from Atmospheric Infrared Sounder (AIRS) and their current accuracies as demonstrated through validation efforts. It also summarizes ongoing research using AIRS data for weather prediction and improving climate models.

  9. Progress in developing GeoSTAR - Microwave Sounder for GOES-R

    NASA Technical Reports Server (NTRS)

    Lambrigtsen, Bjorn H.; Brown, S. T.; Dinardo, S. J.; Kangaslahti, P. P.; Tanner, A. B.; Wilson, W. J.

    2005-01-01

    The Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR)is a new concept for a microwave sounder, intended to be deployed at the Jet Propulsion Laboratory under NASA Instrument Incubator Program sponsorship, and is currently undergoing tests and performance characterization.

  10. 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.

  11. Joule Heating as a Signature of Magnetosphere-Ionosphere-Thermosphere Coupling

    NASA Astrophysics Data System (ADS)

    Ceren Kalafatoglu Eyiguler, Emine; Kaymaz, Zerefsan

    2016-07-01

    Since its first proposal by Birkeland in the early 1900s, the link between magnetosphere and ionosphere (M-I) has been immensely studied but there are still great variety of unsolved problems ranging from how to correctly balance the field aligned current (FAC) closure in the ionosphere to the resulting interactions between ions and neutrals in the ionosphere, and how the ionospheric conductivity and neutral wind control the M-I feedback to the mapping of the ionospheric regions to the magnetotail. It is now well known that during magnetically disturbed periods, the energy deposited to the magnetosphere by the solar wind is partitioned mainly between three domains: the ring current, ionosphere (via auroral particle precipitation and Joule heating) and the plasmoid release in the magnetotail. It is previously found that large part of this transferred energy is in the form of Joule heating which is the increase in ion-neutral collisions due to the increased energy input. However, Joule heating is also affected by the enhanced neutral wind motion during geomagnetic storms and substorms. Thus, it is one of the key manifestations of the M-I-T coupling. In this talk, we first give a through review of the present studies and recent advancements in the M-I-T research area then show the link between the magnetosphere and ionosphere by investigating the activity-time Joule heating variations as well as paying special attention to the neutral wind effects on Joule heating.

  12. A study of the Ionospheric electron density profile with FORMOSAT-3/COSMIC observation data

    NASA Astrophysics Data System (ADS)

    Chou, Min-Yang; Tsai, Ho-Fang; Lin, Chi-Yen; Lee, I.-Te; Lin, Charles; Liu, Jann-Yenq

    2015-04-01

    The GPS Occultation Experiment payload onboard FORMOSAT-3/COSMIC microsatellite constellation is capable of scanning the ionospheric structure by the radio occultation (RO) technique to retrieve precise electron density profiles since 2006. Due to the success of FORMOSAT-3/COSMIC, the follow-on mission, FORMOSAT-7/COSMIC-2, is to launch 12 microsatellites in 2016 and 2018, respectively, with the Global Navigation Satellite Systems (GNSS) RO instrument onboard for tracking GPS, Galileo and/or GLONASS satellite signals and to provide more than 8,000 RO soundings per day globally. An overview of the validation of the FORMOSAT-3/COSMIC ionospheric profiling is given by means of the traditional Abel transform through bending angle and total electron content (TEC), while the ionospheric data assimilation is also applied, based on the Gauss-Markov Kalman filter with the International Reference Ionosphere model (IRI-2007) and global ionosphere map (GIM) as background model, to assimilate TEC observations from FORMOSAT-3/COSMIC. The results shows comparison of electron density profiles from Abel inversion and data assimilation. Furthermore, an observing system simulation experiment is also applied to determine the impact of FORMOSAT-7/COSMIC-2 on ionospheric weather monitoring, which reveals an opportunity on advanced study of small spatial and temporal variations in the ionosphere.

  13. Evidence of scale height variations in the Martian ionosphere over the solar cycle

    NASA Astrophysics Data System (ADS)

    Sánchez-Cano, B.; Lester, M.; Witasse, O.; Milan, S. E.; Hall, B. E. S.; Blelly, P.-L.; Radicella, S. M.; Morgan, D. D.

    2015-12-01

    Solar cycle variations in solar radiation create density changes in any planetary ionosphere, which are well established in the Earth's case. At Mars, however, the ionospheric response to such changes is not well understood. We show the solar cycle impact on the topside ionosphere of Mars, using data from the Mars Advance Radar for Subsurface and Ionospheric Sounding (MARSIS) on board Mars Express. Topside ionospheric variability during the solar cycle is analyzed through neutral scale height behavior. For moderate and high solar activity phases, the topside electron density profile is reproduced with an altitude-variable scale height. However, for the period of extremely low solar activity in 2008 and 2009, the topside was smaller in density than in the other phases of the solar cycle, and there is evidence that it could be reproduced with either a constant scale height or a height-variable scale height with lower electron density. Moreover, the ionosphere during this time did not show any apparent dependence on the EUV flux. This singular behavior during low solar activity may respond to the presence of an induced magnetic field which can penetrate to lower ionospheric altitudes than in other phases of the solar cycle due to the reduced thermal pressure. Numerical simulations of possible scenarios for two different solar cycle phases indicate that this hypothesis is consistent with the observations.

  14. Assimilative modeling of ionospheric dynamics for nowcasting of HF propagation channels in the presence of TIDs

    NASA Astrophysics Data System (ADS)

    Nickisch, L. J.; Fridman, Sergey; Hausman, Mark; Kraut, Shawn; Zunich, George

    2016-03-01

    The ionospheric data assimilation algorithm called GPS Ionospheric Inversion (GPSII; pronounced "gypsy") has been extended and employed to model the dynamic ionosphere, including medium-scale traveling ionospheric disturbances (MS-TIDs). MS-TIDs are characterized by periods of 10-30 min. GPSII can assimilate many forms of ionospheric-related data, including ionogram data and GPS L1/L2 beacon data. For this present effort, GPSII was extended to assimilate propagation time delay, integrated Doppler shift, and angle-of-arrival (AoA) measurements of HF transmissions from known reference points (KRPs). GPSII applies a regularization technique that constrains the solver to find the smoothest 3-D ionosphere model that still reproduces the input data to within their respective errors of measurement. A companion paper documents the development of the assimilation capability for KRPs. In this paper we show test results of the model's performance in reproducing measured AoA variations in the presence of medium-scale traveling ionospheric disturbances (MS-TIDs) using near vertical incidence skywave data collected at White Sands Missile Range by the Intelligence Advanced Research Projects Activity HFGeo Program Government team. We find that using three KRPs within approximately 50 km of reference/check/nonassimilated transmitters, we can reproduce the measured AoAs of the nonassimilated transmitters to within 1.9° with 90% confidence even in the presence of highly dynamic MS-TIDs.

  15. Hyperspectral Microwave Atmospheric Sounder (HyMAS) Architecture and Design Accommodations

    NASA Technical Reports Server (NTRS)

    Hilliard, Lawrence; Racette, Paul; Blackwell, William; Galbraith, Christopher; Thompson, Erik

    2013-01-01

    The Hyperspectral Microwave Atmospheric Sounder (HyMAS) is being developed at Lincoln Laboratories and accommodated by the Goddard Space Flight Center for a flight opportunity on a NASA research aircraft. The term "hyperspectral microwave" is used to indicate an all-weather sounding that performs equivalent to hyperspectral infrared sounders in clear air with vertical resolution of approximately 1 km. Deploying the HyMAS equipped scanhead with the existing Conical Scanning Microwave Imaging Radiometer (CoSMIR) shortens the path to a flight demonstration. Hyperspectral microwave is achieved through the use of independent RF antennas that sample the volume of the Earth s atmosphere through various levels of frequencies, thereby producing a set of dense, spaced vertical weighting functions. The simulations proposed for HyMAS 118/183-GHz system should yield surface precipitation rate and water path retrievals for small hail, soft hail, or snow pellets, snow, rainwater, etc. with accuracies comparable to those of the Advanced Technology Microwave Sounder. Further improvements in retrieval methodology (for example, polarization exploitation) are expected. The CoSMIR instrument is a packaging concept re-used on HyMAS to ease the integration features of the scanhead. The HyMAS scanhead will include an ultra-compact Intermediate Frequency Processor (IFP) module that is mounted inside the door to improve thermal management. The IFP is fabricated with materials made of Low-Temperature Co-fired Ceramic (LTCC) technology integrated with detectors, amplifiers, A/D conversion and data aggregation. The IFP will put out 52 channels of 16 bit data comprised of 4-9 channel data streams for temperature profiles and 2-8 channel streams for water vapor. With the limited volume of the existing CoSMIR scanhead and new HyMAS front end components, the HyMAS team at Goddard began preliminary layout work inside the new drum. Importing and re-using models of the shell, the scan head computer

  16. Hyperspectral Microwave Atmospheric Sounder (HyMAS) architecture and design accommodations

    NASA Astrophysics Data System (ADS)

    Hilliard, L.; Racette, P.; Blackwell, W.; Galbraith, C.; Thompson, E.

    The Hyperspectral Microwave Atmospheric Sounder (HyMAS) is being developed at Lincoln Laboratories and accommodated by the Goddard Space Flight Center for a flight opportunity on a NASA research aircraft. The term “ hyperspectral microwave” is used to indicate an all-weather sounding that performs equivalent to hyperspectral infrared sounders in clear air with vertical resolution of approximately 1 km. Deploying the HyMAS equipped scanhead with the existing Conical Scanning Microwave Imaging Radiometer (CoSMIR) shortens the path to a flight demonstration. Hyperspectral microwave is achieved through the use of independent RF antennas that sample the volume of the Earth's atmosphere through various levels of frequencies, thereby producing a set of dense, spaced vertical weighting functions. The simulations proposed for HyMAS 118/183-GHz system should yield surface precipitation rate and water path retrievals for small hail, soft hail, or snow pellets, snow, rainwater, etc. with accuracies comparable to those of the Advanced Technology Microwave Sounder. Further improvements in retrieval methodology (for example, polarization exploitation) are expected. The CoSMIR instrument is a packaging concept re-used on HyMAS to ease the integration features of the scanhead. The HyMAS scanhead will include an ultra-compact Intermediate Frequency Processor (IFP) module that is mounted inside the door to improve thermal management. The IFP is fabricated with materials made of Low-Temperature Co-fired Ceramic (LTCC) technology integrated with detectors, amplifiers, A/D conversion and data aggregation. The IFP will put out 52 channels of 16 bit data comprised of 4 - 9 channel data streams for temperature profiles and 2-8 channel streams for water vapor. With the limited volume of the existing CoSMIR scanhead and new HyMAS front end components, the HyMAS team at Goddard began preliminary layout work inside the new drum. Importing and re-using models of the shell, the s- an head

  17. 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.

  18. Ionospheric refraction correction in radio astronomy

    NASA Astrophysics Data System (ADS)

    Chai, Yan; Han, Wen-Jun

    1986-10-01

    Using Snell's law in polar coordinates, the ionospheric refraction effects on the declination and right ascension determination are discussed in this paper. A ray tracing method is also given. With the ionospheric data observed in Beijing, the correction of ionospheric refraction is estimated and some useful conclusions are drawn.

  19. Ionospheric ion temperature forecasting in multiples of 27 days

    NASA Astrophysics Data System (ADS)

    Sojka, Jan J.; Schunk, Robert W.; Nicolls, Michael J.

    2014-03-01

    The ionospheric variability found at auroral locations is usually assumed to be unpredictable. The magnetosphere, which drives this ionospheric variability via storms and substorms, is at best only qualitatively describable. In this study we demonstrate that over a 3 year period, ionospheric variability observed from Poker Flat, Alaska, has, in fact, a high degree of long-term predictability. The observations used in this study are (a) the solar wind high speed stream velocity measured by the NASA Advanced Composition Explorer satellite, used to define the corotating interaction region (CIR), and (b) the ion temperature at 300 km altitude measured by the National Science Foundation Poker Flat Incoherent Scatter Radar over Poker Flat, Alaska. After determining a seasonal and diurnal climatology for the ion temperature, we show that the residual ion temperature heating events occur synchronously with CIR-geospace interactions. Furthermore, we demonstrate examples of ion temperature forecasting at 27, 54, and 81 days. A rudimentary operational forecasting scenario is described for forecasting recurrence 27 days ahead for the CIR-generated geomagnetic storms. These forecasts apply specifically to satellite tracking operations (thermospheric drag) and emergency HF-radio communications (ionospheric modifications) in the polar regions. The forecast is based on present-day solar and solar wind observations that can be used to uniquely identify the coronal hole and its CIR. From this CIR epoch, a 27 day forecast is then made.

  20. Validation of the Radiometric Stability of the Atmospheric Infrared Sounder

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.; Elliott, D.; Strow, L. L.

    2012-01-01

    It has been widely accepted that an infrared sounder in low polar orbit is capable of producing climate quality data, if the spectral brightness temperatures have instrumental trends of less than 10 mK/yr. Achieving measurement stability at this level is not only very demanding of the design of the instrument, it is also pushes the state of art of measuring on orbit what stability is actually achieved. We discuss this using Atmospheric Infrared Sounder (AIRS) L1B data collected between 2002 and 2011. We compare the L1B brightness temperature observed in cloud filtered night tropical ocean spectra (obs) to the brightness temperature calculated based on the known surface emissivity, temperature and water vapor profiles from the ECMWF ReAnalysis (ERA) and the growth rates of CO2, N2O and Ozone. The trend in (obs-calc) is a powerful tool for the evaluation of the stability of the 2378 AIRS channels. We divided the channels into seven classes: All channels which sound in the stratosphere (at pressure levels below 150 hPa), 14 micron CO2 sounding, 4 micron CO2 P-branch sounding, 4 micron CO2 R-branch sounding, water vapor sounding, shortwave surface sounding and longwave surface sounding. The peak in the weighting function at 1050 hPa separates sounding and surface channels. The boundary between shortwave and longwave is 5 microns. Except for the stratosphere sounding channels, the remaining six groups have (obs-calc) trends of less than 20 mK/yr. The longwave surface channels have trends of 2 mK/yr, significantly less than the 8 mK/yr trend seem in the shortwave window channels. Based on the design of the instrument, trends within a group of channels should be the same. While the longwave and shortwave trends are less than the canonical 10 mK/yr, the larger trend in the shortwave channels could be an artifact of using the pre-launch determined calibration coefficients. This is currently under evaluation. The trend in (obs-calc) for the non-surface sounding channels, in

  1. Validation of the radiometric stability of the Atmospheric Infrared Sounder

    NASA Astrophysics Data System (ADS)

    Aumann, H. H.; Elliott, D.; Strow, L. L.

    2012-09-01

    It has been widely accepted that an infrared sounder in low polar orbit is capable of producing climate quality data, if the spectral brightness temperatures have instrumental trends of less than 10 mK/yr. Achieving measurement stability at this level is not only very demanding of the design of the instrument, it is also pushes the state of art of measuring on orbit what stability is actually achieved. We discuss this using Atmospheric Infrared Sounder (AIRS) L1B data collected between 2002 and 2011. We compare the L1B brightness temperature observed in cloud filtered night tropical ocean spectra (obs) to the brightness temperature calculated based on the known surface emissivity, temperature and water vapor profiles from the ECMWF ReAnalysis (ERA) and the growth rates of CO2 , N2O and Ozone. The trend in (obscalc) is a powerful tool for the evaluation of the stability of the 2378 AIRS channels. We divided the channels into seven classes: All channels which sound in the stratosphere (at pressure levels below 150 hPa), 14 um CO2 sounding, 4 um CO2 P-branch sounding, 4um CO2 R-branch sounding, water vapor sounding, shortwave surface sounding and longwave surface sounding. The peak in the weighting function at 1050 hPa separates sounding and surface channels. The boundary between shortwave and longwave is 5 μm. Except for the stratosphere sounding channels, the remaining six groups have (obs-calc) trends of less than 20 mK/yr. The longwave surface channels have trends of 2 mK/yr, significantly less than the 8 mK/yr trend seem in the shortwave window channels. Based on the design of the instrument, trends within a group of channels should be the same. While the longwave and shortwave trends are less than the canonical 10 mK/yr, the larger trend in the shortwave channels could be an artifact of using the pre-launch determined calibration coefficients. This is currently under evaluation. The trend in (obs-calc) for the non-surface sounding channels, in particular for

  2. IBuoy: Expendable Echo Sounder Buoy with Satellite Data Telemetry

    NASA Astrophysics Data System (ADS)

    Greenspan, D. G.; Porter, D. L.; Chayes, D. N.

    2012-12-01

    The IBuoy is a small expendable buoy platform with satellite data telemetry that can be deployed for different measurements, such as a wave spectrum (Porter and Keller, 2012). The IBuoy in its wave measuring version allows a user to deploy a small float, (25 cm high, 30 cm in diameter, 2.8 kg), which measures the instrument's motion for 20 minutes, processes the data for 5 minutes, and telemeters the processed data via Iridium modem to the user. In the spring of 2012 this system was modified by replacing the internal motion sensor with a connection to the Lamont-Doherty Earth Observatory's (LDEO) prototype Seafloor Sounding in Polar and Remote (SSPARR) echo sounder (Anderson et. al, 2005). From May 3 through May 19, 2012, this prototype was deployed nine times during the NSF-funded Switchyard field program at thin hole rosette sites (Smethie et. al, 2011). At three sites it was deployed in the beacon-mode, and at six other sites in the SSPARR mode with one of the sites being within ~400 km of the North Pole. In beacon-mode the IBuoy reports positions over time allowing accurate estimates of true ice motion. When it is in the beacon- and depth-mode, an acoustic transducer is deployed through a 12 inch hole in the ice and connected to the SSPARR sounder with the IBuoy on the ice surface. In this configuration it measures the water depth from the submerged transducer to the ocean floor below. Now that the concept has successfully been tested, the goal is to deploy similar IBuoy/SSPARRs at a number of sites for a season and collect positional data and depth soundings as the ice moves. The IBuoy concept provides a highly capable inexpensive platform that can be configured for a variety of measurements. References: Porter, D. L. and K. H. Keller, "IBuoy: Expendable Short Time Duration Wave Buoy with Satellite Data Telemetry," OCEANS '12, Hampton Roads, VA, 14-19 October, 2012. Smethie, W.M. Jr., D. Chayes, R. Perry, and P. Schlosser. 2011. A lightweight vertical rosette

  3. Ionospheres of the terrestrial planets

    NASA Astrophysics Data System (ADS)

    Schunk, R. W.; Nagy, A. F.

    1980-11-01

    The theory and observations relating to the ionospheres of the terrestrial planets Venus, the earth, and Mars are reviewed. Emphasis is placed on comparing the basic differences and similarities between the planetary ionospheres. The review covers the plasma and electric-magnetic field environments that surround the planets, the theory leading to the creation and transport of ionization in the ionospheres, the relevant observations, and the most recent model calculations. The theory section includes a discussion of ambipolar diffusion in a partially ionized plasma, diffusion in a fully ionized plasma, supersonic plasma flow, photochemistry, and heating and cooling processes. The sections on observations and model calculations cover the neutral atmosphere composition, the ion composition, the electron density, and the electron, ion, and neutral temperatures.

  4. Ionospheres of the terrestrial planets

    NASA Technical Reports Server (NTRS)

    Schunk, R. W.; Nagy, A. F.

    1980-01-01

    The theory and observations relating to the ionospheres of the terrestrial planets Venus, the earth, and Mars are reviewed. Emphasis is placed on comparing the basic differences and similarities between the planetary ionospheres. The review covers the plasma and electric-magnetic field environments that surround the planets, the theory leading to the creation and transport of ionization in the ionospheres, the relevant observations, and the most recent model calculations. The theory section includes a discussion of ambipolar diffusion in a partially ionized plasma, diffusion in a fully ionized plasma, supersonic plasma flow, photochemistry, and heating and cooling processes. The sections on observations and model calculations cover the neutral atmosphere composition, the ion composition, the electron density, and the electron, ion, and neutral temperatures.

  5. Chemical releases in the ionosphere

    NASA Technical Reports Server (NTRS)

    Davis, T. N.

    1979-01-01

    The study of the interaction between the atmosphere, ionosphere and magnetosphere is identified as a major task worthy of pursuit. The present review demonstrates the major contributions to this complex problem already made by active experiments involving the injection of chemicals and energetic electron beams into the atmosphere, ionosphere and magnetosphere. Through the use of chemical releases, it has been possible to investigate a number of quantities including high-altitude winds and electric fields, the detailed configurations of the geomagnetic field within the ionosphere and the magnetosphere, as well as the propagation of energetic particle beams and their interaction with natural neutral and ionized constituents of the high atmosphere. So far, virtually all of this effort has been accomplished using rockets. In the future, it is obvious that satellite platforms will play a greater role, both in making injections and in observing their effects.

  6. Global measurements of wind fields using the Laser Atmospheric Wind Sounder (LAWS) on the Earth Observing System (EOS)

    NASA Technical Reports Server (NTRS)

    Fitzjarrald, Daniel E.

    1988-01-01

    The technology for measuring global wind fields in space by the Laser Atmospheric Wind Sounder (LAWS) to be flown on the Earth Observing System (EOS) is discussed. Studies initiated by NASA to determine the feasibility of using Doppler lidar from a platform in space to measure the wind globally have shown the general feasibility of the technique and have identified the technological problems that need to be resolved. Among the lidar systems being evaluated, CO2 coherent detection lidar is given special consideration. A comprehensive research program, the Global Backscatter Experiment, has been established to study global distribution of naturally occurring atmospheric aerosols that provide signal return at the wavelengths used by the techniques under consideration. Wind profiles from space will provide essential information for advancing the skill of numerical weather prediction, furthering the present knowledge of the large-scale atmospheric circulation and climate dynamics, and of global biogeochemical and hydrologic cycles.

  7. 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.

  8. 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”.

  9. Wave activity in the Thermosphere-Ionosphere system as determined from Dynasonde data

    NASA Astrophysics Data System (ADS)

    Negrea, C.; Zabotin, N. A.; Bullett, T. W.; Godin, O. A.

    2013-12-01

    Unique capabilities of the Dynasonde technique of ionospheric radio sounding allow measuring echo ranges and angles of arrival with high precision. The inversion algorithm NeXtYZ, which is a part of the Dynasonde data analysis package, uses this information to restore parameters of a three-dimensional plasma density distribution over the sounder location, including its vertical cross-section (vertical profile) and tilts of constant electron density surfaces as functions of the true altitude. Using results obtained during several campaigns performed at Wallops Island, VA and San Juan, Puerto Rico, we demonstrate how results of this analysis can be used to study temporal spectral characteristics of the wave disturbances at a wide range of thermospheric altitudes. Our method allows for wave activity to be studied at all altitudes where the plasma frequency exceeds the minimum frequency used by the sounder, typically 1.8 MHz, and below the peak 'foF2' frequency. This allows us to survey altitude ranges much higher than those available to most instruments used for gravity wave research. The wave amplitudes and horizontal wavenumbers are determined directly from the data, along with signatures of tidal effects on the ionospheric plasma. No 'by eye' methods are required, all determined quantities are instantaneous and local and the result of automated procedures. The use of autonomous software procedures and the ability of dynasonde stations to operate continuously allow us to process vast amounts of data and obtain results that are truly representative for the local wave activity. High amplitude, low frequency activity is diagnosed using high resolution spectra computed over extended time periods. Also, the time evolution of high-frequency (up to 4 mHz) components is studied using a short (~2 hours) sliding window spectral calculation technique. The procedure has a relatively high sensitivity level and an estimate of it is provided. The observed activity differs

  10. The lower ionosphere of Mars

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Poppoff, I. G.

    1975-01-01

    Recently reported (Savich et al. 1975) results of dual frequency (0.94 and 3.75 GHz) radio occultation experiments indicated the existence of a nocturnal ionospheric layer between the Martian surface and 80 km altitude. It is suggested that the observed ionosphere is due to ionization by galactic cosmic rays. The observed nocturnal electron density profile is compared with that of the negative ion model assumed by Whitten et al. (1971). The profiles are similar below 50 km if the negative ion concentration is reduced by a factor of 10.

  11. Overview of midlatitude ionospheric storms

    NASA Astrophysics Data System (ADS)

    Kintner, Paul; Coster, Anthea; Fuller-Rowell, Tim; Mannucci, Anthony J.

    Solar flares and coronal mass ejections erupting from the roiling Sun can smash into the Earth's magnetosphere causing geomagnetic storms that penetrate deep into the atmosphere, which can short out satellites, upset radio communications, disrupt navigation, and even damage terrestrial electrical power grids. Though effects on other regions of the atmosphere have been analyzed, the mechanism by which geomagnetic storms influence the ionosphere's middle latitudes remains poorly understood.This brief report provides an overview of current knowledge in midlatitude ionospheric dynamics and disturbances, from the historic record to recent discoveries presented at a January AGU Chapman Conference.

  12. HF Radio Wave Production of Artificial Ionospheres

    NASA Astrophysics Data System (ADS)

    Carlson, Herbert

    In 1993 it was predicted that artificial ionospheres would be produced by high power HF radio waves, once HF transmitters approached a GWatt ERP. When that threshold was very recently achieved, such production was indeed detected and published at two high latitude high power HF facilities. Here we review: the first-principles logic behind that prediction, which aspects of such production are critically dependent on magnetic latitude, and which aspects of such production depend only on physical parameters independent of latitude. These distinctions follow directly from decomposition of the problem of ionization production into its components of: radio-wave propagation, wave-particle interactions, electron transport, and quantitative elastic/inelastic cross-sections. We outline this analysis to show that, within the context of early observations, the production of ionization is inevitable, and only a question of competing instability thresholds, and scale of ionization production. This illustrates complimentary aeronomy and plasma physics to advance understanding of both.

  13. Thermal Inertia Mapping Using Mars Climate Sounder Measurements.

    NASA Astrophysics Data System (ADS)

    Piqueux, S.; Kleinboehl, A.; Golombek, M. P.

    2014-12-01

    Previous work has shown inter-seasonal variations of the apparent thermal inertia at virtually all Martian latitudes. Because thermal inertia is mainly controlled by low variability parameters (e.g., grain sizes, degree of induration, rock abundance), these variations are usually interpreted in terms of subsurface layering and atmospheric contributions. Using atmospherically corrected surface temperatures at 32 μm wavelength (channel B1) from the Mars Climate Sounder (MCS) onboard Mars Reconnaissance Orbiter, we analyze the inter-seasonal variations of the apparent thermal inertia. We show that most of the previously observed inertia variations are eliminated, indicating that a simple homogeneous regolith structure is sufficient to explain most of the measurements. Also, as expected, a fraction of the observed variations remain, especially at high latitudes. This is consistent with subsurface layering involving water ice below dry regolith inferred from other measurement techniques and modeling. This work strengthens our ability to identify and characterize surface/subsurface material thermal inertias, layering and physical heterogeneities in the Martian surface layer, and will help eliminate seasonal striping on high-resolution inertia maps. In addition to a global scale analysis, we will discuss observations in western Elysium Planitia where the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander is planned to land in September 2016. We will provide predictions of the surface layer thermophysical properties, which are required for safe landing and successful scientific operations on the ground.

  14. Sensitivity Analysis for Atmospheric Infrared Sounder (AIRS) CO2 Retrieval

    NASA Technical Reports Server (NTRS)

    Gat, Ilana

    2012-01-01

    The Atmospheric Infrared Sounder (AIRS) is a thermal infrared sensor able to retrieve the daily atmospheric state globally for clear as well as partially cloudy field-of-views. The AIRS spectrometer has 2378 channels sensing from 15.4 micrometers to 3.7 micrometers, of which a small subset in the 15 micrometers region has been selected, to date, for CO2 retrieval. To improve upon the current retrieval method, we extended the retrieval calculations to include a prior estimate component and developed a channel ranking system to optimize the channels and number of channels used. The channel ranking system uses a mathematical formalism to rapidly process and assess the retrieval potential of large numbers of channels. Implementing this system, we identifed a larger optimized subset of AIRS channels that can decrease retrieval errors and minimize the overall sensitivity to other iridescent contributors, such as water vapor, ozone, and atmospheric temperature. This methodology selects channels globally by accounting for the latitudinal, longitudinal, and seasonal dependencies of the subset. The new methodology increases accuracy in AIRS CO2 as well as other retrievals and enables the extension of retrieved CO2 vertical profiles to altitudes ranging from the lower troposphere to upper stratosphere. The extended retrieval method for CO2 vertical profile estimation using a maximum-likelihood estimation method. We use model data to demonstrate the beneficial impact of the extended retrieval method using the new channel ranking system on CO2 retrieval.

  15. Microwave Limb Sounder/El Nino Watch - December, 1997

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This image shows differences in atmospheric water vapor relative to a normal (average) year in the Earth's upper troposphere about 10 kilometers (6 miles) above the surface. The measurements were taken by the Microwave Limb Sounder (MLS) instrument aboard NASA's Upper Atmosphere Research Satellite (UARS). These data, collected in late December 1997, show higher than normal levels of water vapor (red) over the central and eastern Pacific which indicates the presence of an El Nino condition. At the same time, the western Pacific (blue) is much drier than normal. The unusually moist air above the central and eastern Pacific is a consequence of the much warmer-than-normal ocean waters which occur during El Nino. Warmer water evaporates at a higher rate and the resulting warm moist air rises and forms tall cloud towers. In the tropics, the warm water and the resulting tall cloud towers typically produce large amounts of rain. These data show significant increases in the amount of atmospheric moisture off the coast of Peru and Ecuador since measurements were made in November 1997. The maximum water temperature in the eastern tropical Pacific, as measured by the National Oceanic and Atmospheric Administration (NOAA), is still higher than normal and these high ocean temperatures are likely responsible for an increase in evaporation and the subsequent rise in humidity.

  16. Coherent launch-site atmospheric wind sounder: theory and experiment.

    PubMed

    Hawley, J G; Targ, R; Henderson, S W; Hale, C P; Kavaya, M J; Moerder, D

    1993-08-20

    The coherent launch-site atmospheric wind sounder (CLAWS) is a lidar atmospheric wind sensor designed to measure the winds above space launch facilities to an altitude of 20 km. In our development studies, lidar sensor requirements are defined, a system to meet those requirements is defined and built, and the concept is evaluated, with recommendations for the most feasible and cost-effective lidar system for use as an input to a guidance and control system for missile or spacecraft launches. The ability of CLAWS to meet NASA goals for increased safety and launch/mission flexibility is evaluated in a field test program at Kennedy Space Center (KSC) in which we investigate maximum detection range, refractive turbulence, and aerosol backscattering efficiency. The Nd:YAG coherent lidar operating at 1.06 µm with 1-J energy per pulse is able to make real-time measurements of the three-dimensional wind field at KSC to an altitude of 26 km, in good agreement with our performance simulations. It also shows the height and thickness of the volcanic layer caused by the volcanic eruption of Mount Pinatubo in the Philippines. PMID:20830118

  17. Cloud retrieval using infrared sounder data - Error analysis

    NASA Technical Reports Server (NTRS)

    Wielicki, B. A.; Coakley, J. A., Jr.

    1981-01-01

    An error analysis is presented for cloud-top pressure and cloud-amount retrieval using infrared sounder data. Rms and bias errors are determined for instrument noise (typical of the HIRS-2 instrument on Tiros-N) and for uncertainties in the temperature profiles and water vapor profiles used to estimate clear-sky radiances. Errors are determined for a range of test cloud amounts (0.1-1.0) and cloud-top pressures (920-100 mb). Rms errors vary by an order of magnitude depending on the cloud height and cloud amount within the satellite's field of view. Large bias errors are found for low-altitude clouds. These bias errors are shown to result from physical constraints placed on retrieved cloud properties, i.e., cloud amounts between 0.0 and 1.0 and cloud-top pressures between the ground and tropopause levels. Middle-level and high-level clouds (above 3-4 km) are retrieved with low bias and rms errors.

  18. Validation of UARS Microwave Limb Sounder ClO Measurements

    NASA Technical Reports Server (NTRS)

    Waters, J. W.; Read, W. G.; Froidevaux, L.; Lungu, T. A.; Perun, V. S.; Stachnik, R. A.; Jarnot, R. F.; Cofield, R. E.; Fishbein, E. F.; Flower, D. A.; Burke, J. R.; Hardy, J. C.; Nakamura, L. L.; Ridenoure, B. P.; Shippony, Z.; Thurstans, R. P.; Thurstans, R. P.; Avallone, L. M.; Toohey, D. W.; deZafra, R. L.; Shindell, D. T.

    1996-01-01

    Validation of stratospheric ClO measurements by the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is described. Credibility of the measurements is established by (1) the consistency of the measured ClO spectral emission line with the retrieved ClO profiles and (2) comparisons of ClO from MLS with that from correlative measurements by balloon-based, ground-based, and aircraft-based instruments. Values of "noise" (random), "scaling" (multiplicative), and "bias" (additive) uncertainties are determined for the Version 3 data, in the first version public release of the known artifacts in these data are identified. Comparisons with correlative measurements indicate agreement to within the combined uncertainties expected for MLS and the other measurements being compared. It is concluded that MLS Version 3 ClO data, with proper consideration of the uncertainties and "quality" parameters produced with these data, can be used for scientific analyses at retrieval surfaces between 46 and 1 hPa (approximately 20-50 km in height). Future work is planned to correct known problems in the data and improve their quality.

  19. The Upper Atmosphere Research Satellite microwave limb sounder instrument

    NASA Technical Reports Server (NTRS)

    Barath, F. T.; Chavez, M. C.; Cofield, R. E.; Flower, D. A.; Frerking, M. A.; Gram, M. B.; Harris, W. M.; Holden, J. R.; Jarnot, R. F.; Kloezeman, W. G.

    1993-01-01

    The microwave limb sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is the first satellite experiment using limb sounding techniques at microwave frequencies. Primary measurement objectives are stratospheric ClO, O3, H2O, temperature, and pressure. Measurements are of thermal emission: all are performed simultaneously and continuously and are not degraded by ice clouds or volcanic aerosols. The instrument has a 1.6-m mechanically scanning antenna system and contains heterodyne radiometers in spectral bands centred near 63, 183, and 205 GHz. The radiometers operate at ambient temperature and use Schottky-diode mixers with local oscillators derived from phase-locked Gunn oscillators. Frequency tripling by varactor multipliers generates the 183- and 205-GHz local oscillators, and quasi-optical techniques inject these into the mixers. Six 15-channel filter banks spectrally resolve stratospheric thermal emission lines and produce an output spectrum every 2 s. Thermal stability is sufficient for 'total power' measurements which do not require fast chopping. Radiometric calibration, consisting of measurements of cold space and an internal target, is performed every 65-s limb scan. Instrument in-orbit performance has been excellent, and all objectives are being met.

  20. The TIROS-N high resolution infrared radiation sounder

    NASA Technical Reports Server (NTRS)

    Koenig, E. W.

    1979-01-01

    The high-resolution infrared radiation sounder (HIRS/2) was developed and flown on the Television and Infrared Observation Satellite, N Series (TIROS-N) as one means of obtaining atmospheric vertical profile information. The HIRS/2 receives visible and infrared spectrum radiation through a single telescope and selects 20 narrow spectral channels by means of a rotating filter wheel. A passive radiant cooler provides an operating temperature of 106.7K for the HgCdTe and InSb detectors while the visible detector operates at instrument frame temperature. Low noise amplifiers and digital processing provide 13 bit data for spacecraft data multiplexing and transmission. The qualities of system performance that determine sounding capability are the dynamic range of data collection, the noise equivalent radiance of the system, the registration of the air columns sampled in each channel, and the ability to upgrade the calibration of the instrument to maintain the performance standard throughout life. The basic performance of the instrument in test is described. Early orbital information from the TIROS-N launched on October 13, 1978 are given and some observations on system quality are made.

  1. Scanning Mechanism of the FY-3 Microwave Humidity Sounder

    NASA Technical Reports Server (NTRS)

    Schmid, Manfred; Jing, Li; Hehr, Christian

    2010-01-01

    Astrium GmbH Germany, developed the scanning equipment for the instrument package of the MicroWave Humidity Sounder (MWHS) flying on the FY-3 meteorological satellite (FY means Feng Yun, Wind and Cloud) in a sun-synchronized orbit of 850-km altitude and at an inclination of 98.8 . The scanning mechanism rotates at variable velocity comprising several acceleration / deceleration phases during each revolution. The Scanning Mechanism contains two output shafts, each rotating a parabolic offset Antenna Reflector. The mechanism is operated in closed loop by means of redundant control electronics. MWHS is a sounding radiometer for measurement of global atmospheric water vapour profiles. An Engineering Qualification Model was developed and qualified and a first Flight Model was launched early 2008. The system is now working for more than two years successful in orbit. A second Flight Model of the Antenna Scanning Mechanism and of its associated control electronics was built and delivered to the customer for application on the follow-on spacecraft that will be launched by the end of 2010.

  2. The Mars Climate Sounder In-Flight Positioning Anomaly

    NASA Technical Reports Server (NTRS)

    Jau, Bruno M.; Kass, David

    2008-01-01

    The paper discusses the Mars Climate Sounder (MCS) instrument s in-flight positioning errors and presents background material about it. A short overview of the instrument s science objectives and data acquisition techniques is provided. The brief mechanical description familiarizes the reader with the MCS instrument. Several key items of the flight qualification program, which had a rigorous joint drive test program but some limitations in overall system testing, are discussed. Implications this might have had for the flight anomaly, which began after several months of flawless space operation, are mentioned. The detection, interpretation, and instrument response to the errors is discussed. The anomaly prompted engineering reviews, renewed ground, and some in-flight testing. A summary of these events, including a timeline, is included. Several items of concern were uncovered during the anomaly investigation, the root cause, however, was never found. The instrument is now used with two operational constraints that work around the anomaly. It continues science gathering at an only slightly diminished pace that will yield approximately 90% of the originally intended science.

  3. Investigation of ionospheric effects on SAR Interferometry (InSAR): A case study of Hong Kong

    NASA Astrophysics Data System (ADS)

    Zhu, Wu; Ding, Xiao-Li; Jung, Hyung-Sup; Zhang, Qin; Zhang, Bo-Chen; Qu, Wei

    2016-08-01

    Synthetic Aperture Radar Interferometry (InSAR) has demonstrated its potential for high-density spatial mapping of ground displacement associated with earthquakes, volcanoes, and other geologic processes. However, this technique may be affected by the ionosphere, which can result in the distortions of Synthetic Aperture Radar (SAR) images, phases, and polarization. Moreover, ionospheric effect has become and is becoming further significant with the increasing interest in low-frequency SAR systems, limiting the further development of InSAR technique. Although some research has been carried out, thorough analysis of ionospheric influence on true SAR imagery is still limited. Based on this background, this study performs a thorough investigation of ionospheric effect on InSAR through processing L-band ALOS-1/PALSAR-1 images and dual-frequency Global Positioning System (GPS) data over Hong Kong, where the phenomenon of ionospheric irregularities often occurs. The result shows that the small-scale ionospheric irregularities can cause the azimuth pixel shifts and phase advance errors on interferograms. Meanwhile, it is found that these two effects result in the stripe-shaped features in InSAR images. The direction of the stripe-shaped effects keep approximately constant in space for our InSAR dataset. Moreover, the GPS-derived rate of total electron content change index (ROTI), an index to reflect the level of ionospheric disturbances, may be a useful indicator for predicting the ionospheric effect for SAR images. This finding can help us evaluate the quality of SAR images when considering the ionospheric effect.

  4. Impact of Atmospheric Infrared Sounder (AIRS) Thermodynamic Profiles on Regional Weather Forecasting

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Bradley T.; Jedlovee, Gary J.

    2010-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles with accuracy comparable to that of radiosondes. The purpose of this paper is to describe a procedure to assimilate AIRS thermodynamic profile data into a regional configuration of the Advanced Research Weather Research and Forecasting (WRF-ARW) model using its three-dimension variational (3DVAR) analysis component (WRF-Var). Quality indicators are used to select only the highest quality temperature and moisture profiles for assimilation in both clear and partly cloudy regions. Separate error characteristics for land and water profiles are also used in the assimilation process. Assimilation results indicate that AIRS profiles produce an analysis closer to in situ observations than the background field. Forecasts from a 37-day case study period in the winter of 2007 show that AIRS profile data can lead to improvements in 6-h cumulative precipitation forecasts due to instability added in the forecast soundings by the AIRS profiles. Additionally, in a convective heavy rainfall event from February 2007, assimilation of AIRS profiles produces a more unstable boundary layer resulting in enhanced updrafts in the model. These updrafts produce a squall line and precipitation totals that more closely reflect ground-based observations than a no AIRS control forecast. The location of available high-quality AIRS profiles ahead of approaching storm systems is found to be of paramount importance to the amount of impact the observations will have on the resulting forecasts.

  5. The Impact of Atmospheric InfraRed Sounder (AIRS) Profiles on Short-term Weather Forecasts

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Brad; Jedlovec, Gary J.; Lapenta, William

    2007-01-01

    The Atmospheric Infrared Sounder (AIRS), together with the Advanced Microwave Sounding Unit (AMSU), represents one of the most advanced spacebased atmospheric sounding systems. The combined AlRS/AMSU system provides radiance measurements used to retrieve temperature profiles with an accuracy of 1 K over 1 km layers under both clear and partly cloudy conditions, while the accuracy of the derived humidity profiles is 15% in 2 km layers. Critical to the successful use of AIRS profiles for weather and climate studies is the use of profile quality indicators and error estimates provided with each profile Aside form monitoring changes in Earth's climate, one of the objectives of AIRS is to provide sounding information of sufficient accuracy such that the assimilation of the new observations, especially in data sparse region, will lead to an improvement in weather forecasts. The purpose of this paper is to describe a procedure to optimally assimilate highresolution AIRS profile data in a regional analysis/forecast model. The paper will focus on the impact of AIRS profiles on a rapidly developing east coast storm and will also discuss preliminary results for a 30-day forecast period, simulating a quasi-operation environment. Temperature and moisture profiles were obtained from the prototype version 5.0 EOS science team retrieval algorithm which includes explicit error information for each profile. The error profile information was used to select the highest quality temperature and moisture data for every profile location and pressure level for assimilation into the ARPS Data Analysis System (ADAS). The AIRS-enhanced analyses were used as initial fields for the Weather Research and Forecast (WRF) system used by the SPORT project for regional weather forecast studies. The ADASWRF system will be run on CONUS domain with an emphasis on the east coast. The preliminary assessment of the impact of the AIRS profiles will focus on quality control issues associated with AIRS

  6. Impact of Atmospheric Infrared Sounder (AIRS) Thermodynamic Profiles on Regional Precipitation Forecasting

    NASA Technical Reports Server (NTRS)

    Chou, S.-H.; Zavodsky, B. T.; Jedloved, G. J.

    2010-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles in clear and cloudy regions with accuracy which approaches that of radiosondes. The purpose of this paper is to describe an approach to assimilate AIRS thermodynamic profile data into a regional configuration of the Advanced Research WRF (ARW) model using WRF-Var. Quality indicators are used to select only the highest quality temperature and moisture profiles for assimilation in clear and partly cloudy regions, and uncontaminated portions of retrievals above clouds in overcast regions. Separate error characteristics for land and water profiles are also used in the assimilation process. Assimilation results indicate that AIRS profiles produce an analysis closer to in situ observations than the background field. Forecasts from a 37-day case study period in the winter of 2007 show that AIRS profile data can lead to improvements in 6-h cumulative precipitation forecasts resulting from improved thermodynamic fields. Additionally, in a convective heavy rainfall event from February 2007, assimilation of AIRS profiles produces a more unstable boundary layer resulting in enhanced updrafts in the model. These updrafts produce a squall line and precipitation totals that more closely reflect ground-based observations than a no AIRS control forecast. The location of available high-quality AIRS profiles ahead of approaching storm systems is found to be of paramount importance to the amount of impact the observations will have on the resulting forecasts.

  7. Holes in the nightside ionosphere of Venus

    NASA Technical Reports Server (NTRS)

    Brace, L. H.; Theis, R. F.; Mayr, H. G.; Curtis, S. A.; Luhmann, J. G.

    1982-01-01

    Measurements of electron density and temperature by the Pioneer Venus orbiter electron temperature probe have been employed to examine the characteristics and morphology of ionospheric holes in the antisolar ionosphere of Venus. The holes apparently exist as north-south pairs which penetrate the ionosphere vertically down to altitudes as low as 160 km. Magnetic field measurements show that the holes are permeated by strong radial fields whose pressure is sufficient to balance the plasma pressure of the surrounding ionosphere. The electron temperature in the holes is substantially cooler than the surrounding ionosphere, except in the lowest density regions of the holes where the temperatures greatly exceed the ionosphere temperature. The low temperatures and the low densities of the holes are consistent with the strong radial magnetic fields which inhibit horizontal transport of plasma and thermal energy from the surrounding ionosphere. Plasma depletion processes associated with magnetotail electric fields may be important in the formation of the holes.

  8. Modeling impact of FORMOSAT-7/COSMIC-2 mission on ionospheric space weather monitoring

    NASA Astrophysics Data System (ADS)

    Lee, I. T.; Tsai, H. F.; Liu, J. Y.; Lin, C. H.; Matsuo, T.; Chang, L. C.

    2013-10-01

    the past decade, the paucity of ionospheric observations has made it almost impossible to reconstruct the three-dimensional structures of global ionospheric electron density. The Formosa Satellite-3/Constellation Observing System for Meteorology, Ionosphere and Climate (FORMOSAT-3/COSMIC, F3/C) constellation has provided ionospheric electron density profiles with high vertical resolution through radio occultation measurements. Slated for deployment starting in 2016, the FORMOSAT-7/COSMIC-2 (F7/C2) constellation will further provide more than 4 times the number of the F3/C occultation soundings. An observing system simulation experiment is conducted to determine the impact of F7/C2 on ionospheric weather monitoring. The results first show that the F7/C2 observations can reconstruct 3-D ionospheric structure with a data accumulation period of 1 h, which can advance studies of small spatial/temporal scale variation/signatures in the ionosphere. Comparing to assimilation results of F3/C, the assimilation system significantly reduces the error arising in the models and observations after assimilating synthetic observations of F7/C2. During this observing system simulation experiment period, the averaged root-mean-square error percentage for the results of F7/C2 is about 4.4%, lower than that of F3/C 7.3%. Furthermore, even with an assimilation window of less than 60 min, the F7/C2 RMS errors still yield reliable values compared to the F3/C results. This paper represents a major advance in ionospheric weather monitoring for the future mission.

  9. Calibrating for Ionospheric Phase Delays

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.

    1985-01-01

    Technique determines ionospheric phase delay on real-time universally applicable basis in terms of electrons per meter squared by coherently modulating two L-band carrier frequencies received from two Global Positioning System satelites. Two pseudorandom number sequences cross-correlated to derive delay time.

  10. 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.

  11. 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.

  12. IONOTOMO: A new approach for ionospheric tomography using OTH radar

    NASA Astrophysics Data System (ADS)

    Roy, Corinna; Occhipinti, Giovanni; Boschi, Lapo; Moliné, Jean-Philippe

    2013-04-01

    Most of the recent methods in ionospheric tomography are based on the inversion of the Total Electron Content (TEC) measured by ground-based GPS receivers [e.g., Garcia et al. 2008]. As a consequence of the high frequency of the GPS, the electron density structure is principally well reconstructed at the F2 region, where the ionosphere reaches the maximum of ionization, neglecting the lower ionosphere. Here, we develop a new 3D ionospheric tomography method based on the full analysis of over-the-horizon (OTH) radar data. Previous studies in ionospheric tomography by OTH radar (Fridman and Fridman, 1994; Ruelle and Landeau, 1994; Landeau et al., 1997; Fridman, 1998) are all based on the inversion of the leading edge echo curve, consequently an important amount of valuable information present in the data is necessarily neglected. To overcome this limit, we set up a new method, based on the ray-tracing tool TDR [Occhipinti, 2006], to invert the propagation time of electromagnetic waves emitted by monostatic OTH radars. The major advance of our methodology is taking into account, numerically and jointly, not only the speed variation of EM wave induced by the electron density variation (solved analytically with a linear inversion) but also the perturbation in the raypath (nonlinear numerical method). As the present problem is an ill posed problem we calculate the matrix inversion numerically, using a regularisation method (Tikhonov, 1963). We determine the best regularisation parameter using the Lcurve method (Hansen, 2000). We present here the originality and the advantage of our method with a full set of synthetic benchmark highlighting the sensitivity of our tomography to the plasma heterogeneities. Some preliminary test on real data will be presented with a full coverage over Europe. Indeed, the ionospheric tomography by OTH radar, jointly with GPS, could open new exciting perspective in the plasma density estimation with a good resolution to the entire ionosphere

  13. Multiparametric study of polar ionosphere on both hemispheres

    NASA Astrophysics Data System (ADS)

    D'Angelo, Giulia; Alfonsi, Lucilla; Spogli, Luca; Cesaroni, Claudio; Sgrigna, Vittorio

    2016-04-01

    The polar ionosphere is a complex system in which several actors concur to establish the observed medium. Indeed the coupling between the interplanetary magnetic field and the earth magnetic field determines a high degree of complexity of the polar ionosphere, which is directly exposed to the variations of the solar wind. This configuration results in a strong sensitivity of the polar ionosphere to the perturbation phenomena caused by solar events which may result in a wide variety of spatial and temporal dimensions of the plasma electron density irregularities. Polar ionospheric irregularities may seriously jeopardize performance and reliability level of the navigation and positioning technological systems, such as GPS or the nascent Galileo. Therefore, knowledge of the physical state of the upper atmosphere ionized layers becomes essential to predict and mitigate events that may affect the use of modern technology, causing economic damage and, in severe cases, even jeopardizing the safety of human beings. In this context, a careful and thorough investigation that covers a wide range of geospatial different disturbances, observed in circumterrestrial space and on the ground, can provide the necessary basis for a real advance of the current knowledge. In this frame, the aim of this work is to contribute to the study of the effects of perturbation induced by the Sun on the polar ionosphere of both the hemispheres, through the analysis and interpretation of the measures available before, during and after the occurrence of an event of disturbance. We propose a multiparametric approach, that combines the information derived from measurements acquired by ground-based and space-based stations, to have a broad spectrum of information necessary to characterize the ionospheric disturbances on different time scales (from milliseconds to days) and spatial scales (from millimetres to hundreds meters/kilometres). The period chosen for this study is the entire month of March

  14. Ionospheric corrections to precise time transfer using GPS

    NASA Technical Reports Server (NTRS)

    Snow, Robert W.; Osborne, Allen W., III; Klobuchar, John A.; Doherty, Patricia H.

    1994-01-01

    The free electrons in the earth's ionosphere can retard the time of reception of GPS signals received at a ground station, compared to their time in free space, by many tens of nanoseconds, thus limiting the accuracy of time transfer by GPS. The amount of the ionospheric time delay is proportional to the total number of electrons encountered by the wave on its path from each GPS satellite to a receiver. This integrated number of electrons is called Total Electron Content, or TEC. Dual frequency GPS receivers designed by Allen Osborne Associates, Inc. (AOA) directly measure both the ionospheric differential group delay and the differential carrier phase advance for the two GPS frequencies and derive from this the TEC between the receiver and each GPS satellite in track. The group delay information is mainly used to provide an absolute calibration to the relative differential carrier phase, which is an extremely precise measure of relative TEC. The AOA Mini-Rogue ICS-4Z and the AOA TurboRogue ICS-4000Z receivers normally operate using the GPS P code, when available, and switch to cross-correlation signal processing when the GPS satellites are in the Anti-Spoofing (A-S) mode and the P code is encrypted. An AOA ICS-Z receiver has been operated continuously for over a year at Hanscom AFB, MA to determine the statistics of the variability of the TEC parameter using signals from up to four different directions simultaneously. The 4-channel ICS-4Z and the 8-channel ICS-4000Z, have proven capabilities to make precise, well calibrated, measurements of the ionosphere in several directions simultaneously. In addition to providing ionospheric corrections for precise time transfer via satellite, this dual frequency design allows full code and automatic codeless operation of both the differential group delay and differential carrier phase for numerous ionospheric experiments being conducted. Statistical results of the data collected from the ICS-4Z during the initial year of

  15. 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.

  16. The ionospheric outflow feedback loop

    NASA Astrophysics Data System (ADS)

    Moore, T. E.; Fok, M.-C.; Garcia-Sage, K.

    2014-08-01

    Following a long period of observation and investigation beginning in the early 1970s, it has been firmly established that Earth's magnetosphere is defined as much by the geogenic plasma within it as by the geomagnetic field. This plasma is not confined to the ionosphere proper, defined as the region within a few density scale heights of the F-region plasma density peak. Rather, it fills the flux tubes on which it is created, and circulates throughout the magnetosphere in a pattern driven by solar wind plasma that becomes magnetically connected to the ionosphere by reconnection through the dayside magnetopause. Under certain solar wind conditions, plasma and field energy is stored in the magnetotail rather than being smoothly recirculated back to the dayside. Its release into the downstream solar wind is produced by magnetotail disconnection of stored plasma and fields both continuously and in the form of discrete plasmoids, with associated generation of energetic Earthward-moving bursty bulk flows and injection fronts. A new generation of global circulation models is showing us that outflowing ionospheric plasmas, especially O+, load the system in a different way than the resistive F-region load of currents dissipating energy in the plasma and atmospheric neutral gas. The extended ionospheric load is reactive to the primary dissipation, forming a time-delayed feedback loop within the system. That sets up or intensifies bursty transient behaviors that would be weaker or absent if the ionosphere did not “strike back” when stimulated. Understanding this response appears to be a necessary, if not sufficient, condition for us to gain accurate predictive capability for space weather. However, full predictive understanding of outflow and incorporation into global simulations requires a clear observational and theoretical identification of the causal mechanisms of the outflows. This remains elusive and requires a dedicated mission effort.

  17. Studies based on global subsurface radar sounding of the Moon by SELENE (Kaguya) Lunar Radar Sounder (LRS): A summary

    NASA Astrophysics Data System (ADS)

    Kumamoto, A.; Yamaguchi, Y.; Yamaji, A.; Kobayashi, T.; Oshigami, S.; Ishiyama, K.; Nakamura, N.; Goto, Y.

    2015-12-01

    The Lunar Radar Sounder (LRS) onboard the SELENE (Kaguya) spacecraft has successfully performed radar sounder observations of the lunar subsurface structures and passive observations of natural radio and plasma waves from the lunar orbit. After the transfer of the spacecraft into the final lunar orbit and antenna deployment, the operation of LRS started on October 29, 2007. Through the operation until June 10, 2009, 130 million pulses worth of radar sounder data have been obtained [Ono et al., 2010]. Based on the datasets of the first lunar global subsurface radar sounding, Ono et al. [2009] revealed that there are distinct reflectors at a depth of several hundred meters in the nearside maria, which are inferred to be buried regolith layers covered by a basalt layer with a thickness of several hundred meters. Based on the further survey, Pommerol et al. [2010] pointed out the negative correlation of clear subsurface echoes with the maps of ilmenite, and suggested that dense ilmenite attenuates the radar pulse in the basaltic mare lava, and cause the absence of the clear subsurface echoes. That also suggests there are undetected subsurface reflectors especially below the young lava flow units with high ilmenite abundance. Kobayashi et al. [2012] applied synthetic aperture radar (SAR) processing to SELENE LRS data in order to obtain distinct radargram. Taking advantage of analyzing waveform data sent via high data rate telemetry from the Moon, we can perform advanced data analyses on the ground. We started providing the both SAR processed and waveform datasets via SELENE Data Archive (http://l2db.selene.darts.isas.jaxa.jp/index.html.en) since 2015. Oshigami et al. [2014] estimated volumes of basalt units in the ages of 2.7 Ga to 3.8 Ga in the nearside maria. The volume was derived from the depth of subsurface reflectors measured by LRS. The volumes of the geologic units were 103 to 104 km3. The average eruption rates were 10-5 to 10-3 km3 yr-1. The estimated volumes

  18. Small particle cirrus observed by the Atmospheric Infrared Sounder

    NASA Astrophysics Data System (ADS)

    Kahn, B. H.; Eldering, A.; Fishbein, E. F.

    2003-04-01

    The high-resolution spectra of the Atmospheric Infrared Sounder (AIRS) have provided an opportunity to globally observe small particle-dominated cirrus clouds. The shape of the radiance spectra in the atmospheric windows is uniquely influenced by small ice crystals with an effective radius (reff) of a few 10s of microns and smaller. In some rare instances, minima in the AIRS brightness temperature (BT) spectra between 800 to 850 cm-1 are seen, consistent with the existence of ice particles with an reff smaller than 3 microns. Much more frequent occurences of small ice particle clouds with reff larger than 3 microns are observed through the large 998 to 811 cm-1 BT differences without minima. The small particle events are occasionally found in orographic cirrus clouds, in and around cumulonimbus towers, and in cirrus bands far removed from convection and orography. Several cases spanning the variety of small particle-dominated cirrus events will be presented. AIRS, located on the EOS-Aqua platform, is a high-resolution grating spectrometer that scans at angles 49.5 degrees on either side of nadir view, at both visible and infrared wavelengths. The surface footprint is 13.5 km at the nadir view, and coverage in the infrared is in three bandpasses (649-1136, 1265-1629, and 2169-2674 cm-1). Comparisons of observed spectra are made with simulated spectra generated by a plane-parallel scattering radiative transfer model using ice particle shapes and sizes calculated by the T-matrix method. These comparisons yield information on small particle cirrus cloud reff and optical depth. Aumann, H.H., and R.J. Pagano, Atmospheric Infrared Sounder on the Earth Observing System. Opt. Eng. 33, 776-784, 1994. Mishchenko, M.I., and L.D. Travis, Capabilities and limitations of a current Fortran implementation of the T-matrix method for randomly oriented, rotationally symmetric scatterers. J. Quant. Spectrosc. Radiat. Transfer, 60, 309-324, 1998. Moncet, J.L., and S.A. Clough

  19. Observation of ionospheric disturbances following a 5-kt chemical explosion. II - Prolonged anomalies and stratifications in the lower thermosphere after shock passage

    NASA Astrophysics Data System (ADS)

    Blanc, Elisabeth; Jacobson, Abram R.

    1989-12-01

    Unusual stratifications and prolonged spectral deformations of radio echoes after the passage through the E region of the shock wave produced by a 5-kt chemical explosion have been observed. The observations were obtained by vertical HF pulsed ionospheric sounding. At the total reflection level of the sounding waves, at a horizontal distance of 30 km from the explosion, the passage of the shock wave generated a complex structure suggesting a significant deformation of the reflecting surface. Irregularities have also been observed in the E region for over 30 min after the shock passage by a network of continuous wave HF ionospheric sounders located 250 km west of the source. The origin of these structures is discussed.

  20. Validation of Aura Microwave Limb Sounder HCl Measurements

    NASA Technical Reports Server (NTRS)

    Froidevaux, L.; Jiang, Y. B.; Lambert, A.; Livesey, N. J.; Read, W. G.; Waters, J. W.; Fuller, R. A.; Marcy, T. P.; Popp, P. J.; Gao, R. S.; Fahey, D. W.; Jucks, K. W.; Stachnik, R. A.; Toon, G. C.; Christensen, L. E.; Webster, C. R.; Bernath, P. F.; Boone, C. D.; Walker, K. A.; Pumphrey, H. C.; Harwood, R. S.; Manney, G. L.; Schwartz, M. J.; Daffer, W. H.; Drouin, B. J.

    2008-01-01

    The Earth Observing System (EOS) Microwave Limb Sounder (MLS) aboard the Aura satellite has provided daily global HCl profiles since August 2004. We provide a characterization of the resolution, random and systematic uncertainties, and known issues for the version 2.2 MLS HCl data. The MLS sampling allows for comparisons with many (1500 to more than 3000) closely matched profiles from the Halogen Occultation Experiment (HALOE) and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). These data sets provide HCl latitudinal distributions that are, overall, very similar to those from (coincident) MLS profiles, although there are some discrepancies in the upper stratosphere between the MLS and HALOE gradients. As found in previous work, MLS and ACE HCl profiles agree very well (within approximately 5%, on average), but the MLS HCl abundances are generally larger (by 10-20%) than HALOE HCl. The bias versus HALOE is unlikely to arise mostly from MLS, as a similar systematic bias (of order 15%) is not observed between average MLS and balloon-borne measurements of HCl, obtained over Fort Sumner, New Mexico, in 2004 and 2005. At the largest pressure (147 hPa) for MLS HCl, a high bias (approximately 0.2 ppbv) is apparent in analyses of low to midlatitude data versus in situ aircraft chemical ionization mass spectrometry (CIMS) HCl measurements from the Aura Validation Experiment (AVE) campaigns in 2004, 2005, and 2006; this bias is also observed in comparisons of MLS and aircraftHCl/O3 correlations. Good agreement between MLS and CIMS HCl is obtained at 100 to 68 hPa. The recommended pressure range for MLS HCl is from 100 to 0.15 hPa.

  1. Global dust infrared aerosol properties retrieved using hyperspectral sounders

    NASA Astrophysics Data System (ADS)

    Capelle, Virginie; Chédin, alain; Pondrom, Marc; Pierangelo, Clémence; Armante, Raymond; Crevoisier, Cyril; Crépeau, Laurent; Scott, Noëlle

    2015-04-01

    Observations from infrared hyperspectral sounders, here IASI and AIRS, are interpreted in terms of dust aerosol properties (AOD and mean altitude). The method is based on a "Look-Up-Table" (LUT) approach, where all radiative transfer computation is performed once for all and "off-line", for a large selection of atmospheric situations, of observing conditions, of surface characteristics (in particular the surface emissivity and temperature), and different aerosol refractive index models. The inversion scheme follows two main steps: first, determination of the observed atmospheric thermodynamic situation, second, simultaneous retrieval of the 10µm coarse-mode AOD and of the mean altitude. The method is here applied over sea and over land, at daily scale daytime and nighttime, and at the satellite pixel resolution (12 km at nadir). The geographical study area studied includes the northern tropics from west Atlantic to the Arabian peninsula and Indian ocean, and the Mediterranean basin, all of them characterized by strong, regular dust events. A special focus is given to the hourly variation of aerosol properties within a day. In this context, both IASI overpasses are processed, providing two measurements at 9:30AM and 9:30PM (equator local time) each day. First results obtained from AIRS observations, made at 1:30 AM and PM, open the way to the analysis of the aerosol diurnal cycle. For the AOD, comparisons are made with AERONET ground-based data , when available, in order to 1) evaluate our results, and 2) show the importance of a better knowledge of the aerosol diurnal cycle, especially close to the sources. Mean aerosol layer altitude obtained from IASI is compared at local scale with the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP/CALIPSO) aerosol altitude.

  2. The UARS and EOS Microwave Limb Sounder (MLS) Experiments.

    NASA Astrophysics Data System (ADS)

    Waters, J. W.; Read, W. G.; Froidevaux, L.; Jarnot, R. F.; Cofield, R. E.; Flower, D. A.; Lau, G. K.; Pickett, H. M.; Santee, M. L.; Wu, D. L.; Boyles, M. A.; Burke, J. R.; Lay, R. R.; Loo, M. S.; Livesey, N. J.; Lungu, T. A.; Manney, G. L.; Nakamura, L. L.;  Perun, V. S.;  Ridenoure, B. P.;  Shippony, Z.;  Siegel, P. H.;  Thurstans, R. P.;  Harwood, R. S.;  Pumphrey, H. C.;  Filipiak, M. J.

    1999-01-01

    The Microwave Limb Sounder (MLS) experiments obtain measurements of atmospheric composition, temperature, and pressure by observations of millimeter- and submillimeter-wavelength thermal emission as the instrument field of view is scanned through the atmospheric limb. Features of the measurement technique include the ability to measure many atmospheric gases as well as temperature and pressure, to obtain measurements even in the presence of dense aerosol and cirrus, and to provide near-global coverage on a daily basis at all times of day and night from an orbiting platform. The composition measurements are relatively insensitive to uncertainties in atmospheric temperature. An accurate spectroscopic database is available, and the instrument calibration is also very accurate and stable. The first MLS experiment in space, launched on the (NASA) Upper Atmosphere Research Satellite (UARS) in September 1991, was designed primarily to measure stratospheric profiles of ClO, O3, H2O, and atmospheric pressure as a vertical reference. Global measurement of ClO, the predominant radical in chlorine destruction of ozone, was an especially important objective of UARS MLS. All objectives of UARS MLS have been accomplished and additional geophysical products beyond those for which the experiment was designed have been obtained, including measurement of upper-tropospheric water vapor, which is important for climate change studies. A follow-on MLS experiment is being developed for NASA's Earth Observing System (EOS) and is scheduled to be launched on the EOS CHEMISTRY platform in late 2002. EOS MLS is designed for many stratospheric measurements, including HOx radicals, which could not be measured by UARS because adequate technology was not available, and better and more extensive upper-tropospheric and lower-stratospheric measurements.

  3. Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 2

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This report summarizes and documents the results of the 12-month phase 1 work effort. The objective of phase 1 was to establish the conceptional definition of the laser atmospheric wind sounder (LAWS) sensor system, including accommodations analyses to ensure compatibility with the Space Station Freedom (SSF) and the Earth Observing System (EOS) Polar Orbiting Platform (POP). Various concepts were investigated with trade studies performed to select the configuration to be carried forward to the phase 2 Preliminary Design Definition. A summary of the LAWS system and subsystem trade studies that were performed leading to the baseline design configuration is presented in the appendix. The overall objective of the LAWS Project is to define, design, and implement an operational space based facility, LAWS, for accurate measurement of Earth wind profiles. Phase 1 addressed three major areas: (1) requirements definition; (2) instrument concepts and configurations; and (3) performance analysis. For the LAWS instrument concepts and configurations, the issues which press the technological state of the art are reliable detector lifetime and laser performance and lifetime. Lag angle compensation, pointing accuracy, satellite navigation, and telescope design are significant technical issues, but they are considered to be currently state of the art. The primary issues for performance analysis concern interaction with the atmosphere in terms of backscatter and attenuation, wind variance, and cloud blockage. The phase 1 tasks were formulated to address these significant technical issues and demonstrate the technical feasibility of the LAWS concept. Primary emphasis was placed on analysis/trade and identification of candidate concepts. Promising configurations were evaluated for performance, sensitivities, risks, and budgetary costs. Lockheed's baseline LAWS configuration is presented.

  4. Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 2

    NASA Astrophysics Data System (ADS)

    1990-04-01

    This report summarizes and documents the results of the 12-month phase 1 work effort. The objective of phase 1 was to establish the conceptional definition of the laser atmospheric wind sounder (LAWS) sensor system, including accommodations analyses to ensure compatibility with the Space Station Freedom (SSF) and the Earth Observing System (EOS) Polar Orbiting Platform (POP). Various concepts were investigated with trade studies performed to select the configuration to be carried forward to the phase 2 Preliminary Design Definition. A summary of the LAWS system and subsystem trade studies that were performed leading to the baseline design configuration is presented in the appendix. The overall objective of the LAWS Project is to define, design, and implement an operational space based facility, LAWS, for accurate measurement of Earth wind profiles. Phase 1 addressed three major areas: (1) requirements definition; (2) instrument concepts and configurations; and (3) performance analysis. For the LAWS instrument concepts and configurations, the issues which press the technological state of the art are reliable detector lifetime and laser performance and lifetime. Lag angle compensation, pointing accuracy, satellite navigation, and telescope design are significant technical issues, but they are considered to be currently state of the art. The primary issues for performance analysis concern interaction with the atmosphere in terms of backscatter and attenuation, wind variance, and cloud blockage. The phase 1 tasks were formulated to address these significant technical issues and demonstrate the technical feasibility of the LAWS concept. Primary emphasis was placed on analysis/trade and identification of candidate concepts. Promising configurations were evaluated for performance, sensitivities, risks, and budgetary costs. Lockheed's baseline LAWS configuration is presented.

  5. Validation of UARS Microwave Limb Sounder Ozone Measurements

    NASA Technical Reports Server (NTRS)

    Froidevaux, L.; Read, W. G.; Lungu, T. A.; Cofield, R. E.; Fishbein, E. F.; Flower, D. A.; Jarnot, R. F.; Ridenoure, B. P.; Shippony, Z.; Waters, J. W.; Margitan, J. J.; McDermid, I. S.; Stachnik, R. A.; Peckham, G. E.; Braathen, G.; Deshler, T.; Fishman, J.; Hofmann, D. J.; Oltmans, S. J.

    1996-01-01

    This paper describes the validation of ozone data from the Upper Atmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS). The MLS ozone retrievals are obtained from the calibrated microwave radiances (emission spectra) in two separate bands, at frequencies near 205 and 183 GHz. Analyses described here focus on the MLS Version 3 data (the first set of files made publicly available). We describe results of simulations performed to assess the quality of the retrieval algorithms, in terms of both mixing ratio and radiance closure. From actual MLS observations, the 205-GHz ozone retrievals give better closure (smaller radiance residuals) than that from the 183-GHz measurements and should be considered more accurate from the calibration aspects. However, the 183-GHz data are less noise limited in the mesosphere and can provide the most useful scientific results in that region. We compare the retrieved 205-GHz ozone profiles in the middle-to lower stratosphere to ozonesonde measurements at a wide range of latitudes and seasons. Ground-based lidar data from Table Mountain, California, provide a good reference for comparisons at higher altitudes. Based on these analyses, comparisons with balloon-borne measurements and others, as well as a detailed budget of estimated uncertainties, MLS results appear to be generally of high quality, with some biases worth mentioning. Results for the lowermost stratosphere (approx. 50 to 100 bPa) are still in need of improvement. A set of estimated precision and accuracy values is derived for the MLS ozone data sets. We also comment on recent updates in the retrieval algorithms and their impact on ozone values.

  6. Mare volcanism: Reinterpretation based on Kaguya Lunar Radar Sounder data

    NASA Astrophysics Data System (ADS)

    Oshigami, Shoko; Watanabe, Shiho; Yamaguchi, Yasushi; Yamaji, Atsushi; Kobayashi, Takao; Kumamoto, Atsushi; Ishiyama, Ken; Ono, Takayuki

    2014-05-01

    The Lunar Radar Sounder (LRS) onboard Kaguya (SELENE) detected widespread horizontal reflectors under some nearside maria. Previous studies estimated that the depths of the subsurface reflectors were up to several hundreds of meters and suggested that the reflectors were interfaces between mare basalt units. The comparison between the reflectors detected in the LRS data and surface age maps indicating the formation age of each basalt unit allows us to discuss the lower limit volume of each basalt unit and its space and time variation. We estimated volumes of basalt units in the ages of 2.7 Ga to 3.8 Ga in the nearside maria including Mare Crisium, Mare Humorum, Mare Imbrium, Mare Nectaris, Mare Serenitatis, Mare Smythii, and Oceanus Procellarum. The lower limit volumes of the geologic units estimated in this study were on the order of 103 to 104 km3. This volume range is consistent with the total amount of erupted lava flows derived from numerical simulations of thermal erosion models of lunar sinuous rille formation and is also comparable to the average flow volumes of continental flood basalt units formed after the Paleozoic and calculated flow volumes of Archean komatiite flows on the Earth. The lower limits of average eruption rates estimated from the unit volumes were on the order of 10-5 to 10-3 km3/yr. The estimated volumes of the geologic mare units and average eruption rate showed clear positive correlations with their ages within the same mare basin, while they vary among different maria compared within the same age range.

  7. ULF Waves and Transients in the Topside Ionosphere

    NASA Astrophysics Data System (ADS)

    Pilipenko, V. A.; Heilig, B.

    2016-02-01

    Low earth orbit satellites with precise high-rate sensors onboard have advanced the prospect of examining the different kinds of ultra-low-frequency (ULF) waves in the topside ionosphere. This chapter reviews more recent observations on the behavior of these wave categories. It examines such evidence from these observations that may help settle some of the unsolved problems of ULF wave physics. To model the interaction with the ionosphere of low-frequency waves with periods T > 20 s, the thin layer approximation can be used. Standard magnetotelluric sounding of the crust conductivity profile is used as a determination of ground impedance from the data of synchronous magnetic and telluric electric field observations on the ground, whereas ULF magnetospheric waves are used as sounding electromagnetic signals. The largest spectral density of the atmospheric electrical discharge is concentrated in the VLF band, though comparable spectral power is contained in the lower ELF-ULF bands.

  8. How Well Can Infrared Sounders Observe the Atmosphere and Surface Through Clouds?

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Larar, Allen M.; Liu, Xu; Smith, William L.; Strow, L. Larrabee; Yang, Ping

    2010-01-01

    Infrared sounders, such as the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared sounder (CrIS), have a cloud-impenetrable disadvantage in observing the atmosphere and surface under opaque cloudy conditions. However, recent studies indicate that hyperspectral, infrared sounders have the ability to detect cloud effective-optical and microphysical properties and to penetrate optically thin clouds in observing the atmosphere and surface to a certain degree. We have developed a retrieval scheme dealing with atmospheric conditions with cloud presence. This scheme can be used to analyze the retrieval accuracy of atmospheric and surface parameters under clear and cloudy conditions. In this paper, we present the surface emissivity results derived from IASI global measurements under both clear and cloudy conditions. The accuracy of surface emissivity derived under cloudy conditions is statistically estimated in comparison with those derived under clear sky conditions. The retrieval error caused by the clouds is shown as a function of cloud optical depth, which helps us to understand how well infrared sounders can observe the atmosphere and surface through clouds.

  9. Field-aligned electron density irregularities near 500 km Equator to polar cap topside sounder observations

    NASA Technical Reports Server (NTRS)

    Benson, R. F.

    1985-01-01

    In addition to spread F, evidence for field-aligned electron density irregularities is commonly observed on Alouette 2 topside sounder ionograms recorded near perigee (500 km). This evidence is provided by distinctive signal returns from sounder-generated Z mode waves. At low latitudes these waves become guided in wave ducts caused by field-aligned electron density irregularities and give rise to strong long-duration echoes. At high latitudes, extending well into the polar cap, these Z mode waves (and stimulated electrostatic waves at the plasma frequency) produce a series of vertical bars on the ionogram display as the satellite traverses discrete field-aligned density structures. The radio frequency (RF) noise environment to be expected in the 400 to 500 km altitude region from low to high latitudes was examined by analyzing perigee Alouette 2 topside sounder data. All observed noise bands were scaled on nearly 200 topside sounder ionograms recorded near perigee at low, mid, and high latitude telemetry stations. The minimum and maximum frequencies of each noise band were entered into a data base or computer analysis. The signals of primary interest in the perigee study were found to be sounder-generated.

  10. Satellite-based Hyperspectral Sounder Retrievals in Real-time Weather Applications

    NASA Astrophysics Data System (ADS)

    Weisz, E.; Smith, N.; Smith, W. L.

    2015-12-01

    Real-time weather monitoring and forecasting abilities have significantly improved by the new generation of weather satellites, which provide routine access to observations and atmospheric data. In addition of providing visual images, satellite-based instrumentation also provide spectral radiance data that allow the computation of atmospheric temperature, moisture and trace gas profiles and other geophysical variables including cloud parameters. Hyperspectral sounders, AIRS (Atmospheric Infrared Sounder), IASI (Infrared Atmospheric Sounding Interferometer) and CrIS (Cross-track Infrared Sounder) on low-Earth orbiting satellites, provide atmospheric profiles on a global scale with the spatial and temporal resolution needed to complement traditional profile data sources such as that obtained by radiosondes. The goal of this paper is to describe the information that hyperspectral sounders are capable of adding to weather monitoring and short-term forecasting systems. Retrievals derived from all four operational sounders are used in time-series to describe the pre-convective environment (including moisture advection and stability tendencies) antecedent to the initiation of severe weather. Temporal and spatial consistency and continuity is achieved among different instruments on different platforms through the use of a single atmospheric profile retrieval algorithm. Our results demonstrate the utility of using hyperspectral sounding products from multiple satellites for the real-time weather monitoring/prediction operation.

  11. A Network of Direct Broadcast Antenna Systems to Provide Real-Time Infrared and Microwave Sounder Data for Numerical Weather Prediction

    NASA Astrophysics Data System (ADS)

    Gumley, L.

    2013-12-01

    The Space Science and Engineering Center at the University of Wisconsin-Madison is creating a network of direct broadcast satellite data reception stations to acquire and process infrared and microwave sounder data in real-time from polar orbiting meteorological satellites and deliver the resulting products to NOAA with low latency for assimilation in NCEP numerical weather prediction models. The network will include 4 antenna sites that will be operated directly by SSEC, including Madison WI, Honolulu HI, Miami FL, and Mayaguez PR. The network will also include partner antenna sites not directly controlled by SSEC, including Corvallis OR, Monterey CA, Suitland MD, Fairbanks AK, and Guam. All of the antenna sites will have a combined X/L-band reception system capable of receiving data via direct broadcast from polar orbiting satellites including Suomi NPP and JPSS-1, Metop-A/B, POES,Terra, and Aqua. Each site will collect raw data from these satellites locally, process it to Level 1 (SDR) and Level 2 (EDR) products, and transmit the products back to SSEC for delivery to NOAA/NCEP. The primary purpose of the antenna systems is to provide real-time infrared and microwave sounder data from Metop and Suomi-NPP to NOAA to support data assimilation for NOAA/NCEP operational numerical weather prediction models. At present, NOAA/NCEP use of advanced infrared (CrIS, IASI, AIRS) and microwave (ATMS, AMSU) sounder data over North America in NWP data assimilation is limited because of the latency of the products in relation to the cutoff times for assimilation runs. This network will deliver infrared and microwave sounder data to NCEP with the lowest latency possible, via the reception and processing of data received via direct broadcast. CIMSS/SSEC is managing the procurement and installation of the antenna systems at the two new sites, and will operate the stations remotely. NOAA will establish the reception priorities (Metop and SNPP will be at the highest priority) and

  12. Atmospheric density remote sensing of mesosphere and thermosphere to be used for spacecraft design by adopting VHF radar and HF Doppler sounder at low latitude West Pacific site during winter

    NASA Astrophysics Data System (ADS)

    Hung, R. J.; Lee, C. C.; Chen, A. J.

    The VHF radar and HF Doppler sounder located at the subtropical and low latitude observing site of Taiwan has been used to make a simultaneous observation for atmospheric parameters from the troposphere, to the middle atmosphere, and then to the thermosphere during the time period of the weak convective motions of cold front in winter time. For observations at mesospheric heights, time dependent wind velocities with three-dimensional profiles are detected in the backscattered power, radial velocities and Doppler spectral width. For observations at thermospheric heights, time-dependent phase path change of high frequency radio wave reflected from ionospheric heights is used to measure Doppler frequency variation of gravity wave parameters. The density perturbations caused by the propagation of the gravity waves due to the weak convective motions in winter time were calculated from the VHF radar and HF Doppler sounder observations simultaneously. These short-term middle atmospheric and thermospheric density changes are a key element needed for space vehicle design purposes. Projects such as the Space Shuttle, Shuttle II, Tethered Satellite, Hubble Space Telescope, Aerobraking Orbital Transfer Vehicle, and Aeroassisted Flight Experiment will benefit from such studies.

  13. The Radiative Consistency of Atmospheric Infrared Sounder and Moderate Resolution Imaging Spectroradiometer Cloud Retrievals

    NASA Technical Reports Server (NTRS)

    Kahn, Brian H.; Fishbein, Evan; Nasiri, Shaima L.; Eldering, Annmarie; Fetzer, Eric J.; Garay, Michael J.; Lee, Sung-Yung

    2007-01-01

    The consistency of cloud top temperature (Tc) and effective cloud fraction (f) retrieved by the Atmospheric Infrared Sounder (AIRS)/Advanced Microwave Sounding Unit (AMSU) observation suite and the Moderate Resolution Imaging Spectroradiometer (MODIS) on the EOS-Aqua platform are investigated. Collocated AIRS and MODIS TC and f are compared via an 'effective scene brightness temperature' (Tb,e). Tb,e is calculated with partial field of view (FOV) contributions from TC and surface temperature (TS), weighted by f and 1-f, respectively. AIRS reports up to two cloud layers while MODIS reports up to one. However, MODIS reports TC, TS, and f at a higher spatial resolution than AIRS. As a result, pixel-scale comparisons of TC and f are difficult to interpret, demonstrating the need for alternatives such as Tb,e. AIRS-MODIS Tb,e differences ((Delta)Tb,e) for identical observing scenes are useful as a diagnostic for cloud quantity comparisons. The smallest values of DTb,e are for high and opaque clouds, with increasing scatter in (Delta)Tb,e for clouds of smaller opacity and lower altitude. A persistent positive bias in DTb,e is observed in warmer and low-latitude scenes, characterized by a mixture of MODIS CO2 slicing and 11-mm window retrievals. These scenes contain heterogeneous cloud cover, including mixtures of multilayered cloudiness and misplaced MODIS cloud top pressure. The spatial patterns of (Delta)Tb,e are systematic and do not correlate well with collocated AIRS-MODIS radiance differences, which are more random in nature and smaller in magnitude than (Delta)Tb,e. This suggests that the observed inconsistencies in AIRS and MODIS cloud fields are dominated by retrieval algorithm differences, instead of differences in the observed radiances. The results presented here have implications for the validation of cloudy satellite retrieval algorithms, and use of cloud products in quantitative analyses.

  14. Ionospheric corrections for GPS time transfer

    NASA Astrophysics Data System (ADS)

    Rose, Julian A. R.; Watson, Robert J.; Allain, Damien J.; Mitchell, Cathryn N.

    2014-03-01

    A real-time ionospheric mapping system is tested to investigate its ability to compensate for the ionospheric delay in single-frequency Global Positioning System (GPS) time transfer over Europe. This technique is compared with two other single-frequency systems: one that does not incorporate any ionospheric correction and one that uses the broadcast Klobuchar model. A dual-frequency technique is also shown as a benchmark. A period in March 2003, during a solar maximum, has been used to display results when the ionospheric delays are large and variable. Data from two European GPS monitoring centers were used to test the time-transfer methods. For averaging times between several minutes and a few hours, the instabilities in the time transfers were dominated by ionospheric effects. The instabilities at longer averaging times were found to be due to clock noise and hardware instabilities. Improvements in time-transfer instabilities are shown by using the ionospheric tomography system.

  15. 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

  16. Evidence and effects of the sunrise enhancement of the equatorial vertical plasma drift in the F region ionosphere

    NASA Astrophysics Data System (ADS)

    Zhang, Ruilong; Liu, Libo; Le, Huijun; Chen, Yiding

    2016-05-01

    Recent studies based on the satellite observations demonstrated that the equatorial vertical plasma drift can also enhance near sunrise in a way similar to the prereversal enhancement. However, it is not clear whether the signature of this sunrise enhancement appears in observations with other sounding techniques. In this work, we explore the Jicamarca (12°S, 283.2°E) incoherent scatter radar measurements to present the evidence of sunrise enhancement in vertical plasma drift on 12 May and 10 June 2004, which are under magnetically quiet and solar minimum conditions. The effects of the sunrise enhancement on the ionosphere are, for the first time, investigated by analyzing the ionograms recorded by the Digisonde Portable Sounder at Jicamarca and conducting the Theoretical Ionospheric Model of the Earth in Institute of Geology and Geophysics, Chinese Academy of Sciences. The observations showed that, during the sunrise enhancement, the F2 layer peak height is lifted remarkably, and the F2 layer peak density and bottomside electron density tend to decrease compared to the days without sunrise enhancements. The simulations indicated that the sunrise enhancement drift can lift the equatorial ionosphere to higher heights and distort the equatorial electron density profiles. What is more, the simulations display an F3 layer in the equatorial F region during the sunrise enhancement, and a new F2 layer develops at lower altitudes under the jointed control of the usual photochemical and dynamical processes.

  17. Analysis of direction-of-arrival aliasing for MF/HF Doppler-sorted interferometry measurements of ionospheric drift

    NASA Astrophysics Data System (ADS)

    Parkinson, M. L.; Dyson, P. L.; Smith, P. R.

    1997-05-01

    The determination of accurate direction of arrival (DOA) of echoes is paramount when performing Doppler-sorted interferometry (DSI) at MF/HF to measure the drift of ionospheric plasma. Important factors affecting the accuracy include inadequate signal-to-noise ratio (SNR) and coherency of ionospheric echoes. As the SNR deteriorates, there is an increase in the errors in the phases measured at the individual antennas of an array, and this leads to ambiguities in DOA equivalent to directional aliasing. In this paper we model this effect, the effects of Doppler-frequency aliasing, and the finite resolution of Doppler spectra. We thereby show the importance for vertical incident sounders of rejecting echoes with large off-vertical angles, and the choice of appropriate signal-processing parameters for the accurate estimation of ionospheric motions. As an example, we consider the situation for vertical incident ionosondes and show that a low SNR can produce spurious echoes at relatively large zenith angles, which can, however, be avoided or minimized by the suitable choice of operating parameters.

  18. New method for deriving the topside ionospheric Vary-Chap scale height

    NASA Astrophysics Data System (ADS)

    Wang, Sicheng; Huang, Sixun; Fang, Hanxian

    2015-09-01

    An α-Chapman function with a continuously varying scale height H(h) can be used to describe the topside ionosphere electron density profile that seamlessly connects the ionosphere with the plasmasphere. Huang and Reinisch have derived the analytic expression of the scale height from the Vary-Chap function, which can be applied to the topside F2 region. However, the H(h) is still difficult to obtain because H(h) is a function of the unknown value H(h) at hmF2. In this paper, the maximum entropy method is introduced to solve this ill-posed problem, and the Vary-Chap scale height for each electron density profile is derived. Then the average percentage errors that defined as the differences between the measured electron density profiles and the Vary-Chap profiles obtained from the Vary-Chap scale heights are calculated with the Alouette/ISIS satellites topside sounder database. The results reveal that the average percentage errors are generally less than 5% and the Vary-Chap profiles can well represent the topside electron density profiles. What is more, the local time, seasonal, solar cycle, and latitudinal variations of the Vary-Chap scale height are preliminarily analyzed.

  19. 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.

  20. Assimilation of Atmospheric InfraRed Sounder (AIRS) Profiles using WRF-Var

    NASA Technical Reports Server (NTRS)

    Zavodsky, Brad; Jedlovec, Gary J.; Lapenta, William

    2008-01-01

    The Weather Research and Forecasting (WRF) model contains a three-dimensional variational (3DVAR) assimilation system (WRF-Var), which allows a user to join data from multiple sources into one coherent analysis. WRF-Var combines observations with a background field traditionally generated using a previous model forecast through minimization of a cost function. In data sparse regions, remotely-sensed observations may be able to improve analyses and produce improved forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), represents one of the most advanced space-based atmospheric sounding systems. The combined AIRS/AMSU system provides radiance measurements used as input to a sophisticated retrieval scheme which has been shown to produce temperature profiles with an accuracy of 1 K over 1 km layers and humidity profiles with accuracy of 15% in 2 km layers in both clear and partly cloudy conditions. The retrieval algorithm also provides estimates of the accuracy of the retrieved values at each pressure level, allowing the user to select profiles based on the required error tolerances of the application. The purpose of this paper is to describe a procedure to optimally assimilate high-resolution AIRS profile data into a regional configuration of the Advanced Research WRF (ARW) version 2.2 using WRF-Var. The paper focuses on development of background error covariances for the regional domain and background field type using gen_be and an optimal methodology for ingesting AIRS temperature and moisture profiles as separate overland and overwater retrievals with different error characteristics in the WRF-Var. The AIRS thermodynamic profiles are obtained from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm and contain information about the quality of each temperature layer. The quality indicators are used to select the highest quality temperature and moisture

  1. Far ultraviolet nighttime ionospheric photometer

    NASA Astrophysics Data System (ADS)

    Fu, Liping; Peng, Ruyi; Shi, Entao; Peng, Jilong; Wang, Tianfang; Jiang, Fang; Jia, Nan; Li, Xiaoyin; Wang, Yongmei

    2015-01-01

    Far Ultraviolet Nighttime Ionopsheric Photometer (FNIP) is a newly-designed instrument for low earth orbit missions, observing the earth night airglow nadir at OI 135.6 nm emission produced by ionospheric O++e recombination and receiving the horizontal information on nighttime ionosphere with a spatial resolution of about 1.6∘×3.8∘. This simple, highly robust instrument excludes OI 130.4 nm emission and Herzberg oxygen bands with lower power and approximately achieves a sensitivity of about 400 counts/s/Rayleigh at 135.6 nm with stray light less than 2 %. Some tests of the instrument have been conducted and the results will be discussed in the end.

  2. Radio tomography of the ionosphere

    SciTech Connect

    Kunitsyn, V.E.; Tereshchenko, E.D. RAN, Poliarnyi Geofizicheskii Inst., Murmansk )

    1992-10-01

    This paper provides on overview of tomographic approaches to ionospheric remote sensing in the radio-wave range. The ionosphere has a very complicated structure. Thus, it is reasonable to divide tomographic methods into deterministic and statistical ones. The deterministic tomography problems can be subdivided into ray radio tomography and diffraction radio tomography. The statistical radio tomography approach is used when it is necessary to reconstruct the statistical structure of a great number of inhomogeneities, on the basis of measurements of field statistics (instead of one realization of the reconstruction of an inhomogeneity). The methods of solving radio-tomography problems, and their connection with inverse-scattering problems, are considered. The results of some first experiments are described, which show the possibilities of the radio tomography approaches. In conclusion, we discuss perspectives, directions of the development of radio tomography, and problems which appear. 30 refs.

  3. Investigation of traveling ionospheric disturbances

    NASA Technical Reports Server (NTRS)

    Grossi, M.; Estes, R. D.

    1981-01-01

    Maximum entropy power spectra of the ionospheric electron density were constructed to enable PINY to compare them with the power independently obtained by PINY with in situ measurements of ionospheric electron density and neutral species performed with instrumentation carried by the Atmospheric Explorer (AE) satellite. This comparison corroborated evidence on the geophysical reality of the alleged electron density irregularities detected by the ASTP dual frequency Doppler link. Roughly half of the localized wave structures which are confined to dimensions of 1800 km or less (as seen by an orbiting Doppler baseline) were found to be associated with the larger crest of the geomagnetic anomaly in the Southern (winter) Hemisphere in the morning. The observed nighttime structures are also associated with local peaks in the electron density.

  4. 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.

  5. 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

  6. 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.).

  7. Sudden ionospheric disturbances in solar cycle 24

    NASA Astrophysics Data System (ADS)

    Bothmer, Volker; Bernert, Barbara

    2014-05-01

    Sudden ionospheric disturbances in solar cycle 24 Within the framework of the UN International Space Weather Initiative, and building upon the achievements of the International Heliophysical Year, the German project SIMONE (Sun Ionosphere MOnitoring NEtwork) operates several SID monitors provided by the University of Stanford. Here we present an overview of sudden ionospheric disturbances recorded since 2006 at the high school Gymnasium Walsrode until to date. The continous measurements allow a detailed comparison of locally measured SIDs with the general trend of solar activity during the current solar maximum. We further show that the measurements reveal specific information on the variable response of the dayside ionosphere to solar flares.

  8. 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.

  9. 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

  10. Solar Rotational Effects on the Mars Ionosphere

    NASA Astrophysics Data System (ADS)

    Talaat, E. R.; Paxton, L.; Zhu, X.; Yee, J.; Smith, D. C.

    2006-05-01

    In this paper, using opportune periods during the five years of MGS radio occultation observations of the Martian ionosphere, we examine the short-term variability in the ionospheric profile peak densities and peak heights. During solar maximum, strong solar rotational signatures were observed. On Mars, the morphology of the ionosphere is thought to be controlled by photochemical processes (coupled with the neutral atmosphere). In this paper, we will present the observed magnitude of the variabilities the phasing with solar forcing, and quantify the source mechanisms with a 1-D ionospheric model.

  11. Plasma temperatures in Saturn's ionosphere

    NASA Astrophysics Data System (ADS)

    Moore, Luke; Galand, Marina; Mueller-Wodarg, Ingo; Yelle, Roger; Mendillo, Michael

    2008-10-01

    We have calculated self-consistent electron and ion temperatures in Saturn's ionosphere using a series of coupled fluid and kinetic models developed to help interpret Cassini observations and to examine the energy budget of Saturn's upper atmosphere. Electron temperatures in the midlatitude topside ionosphere during solar maximum are calculated to range between 500 and 560 K during the Saturn day, approximately 80-140 K above the neutral temperature. Ion temperatures, calculated for only the major ions H+ and H3+, are nearly equal to the neutral temperature at altitudes near and below the height of peak electron density, while they can reach 500 K during the day at the topside. Plasma scale heights of the dusk electron density profile from radio occultation measurements of the Voyager 2 flyby of Saturn have been used to estimate plasma temperature as a comparison. Such an estimate agrees well with the temperatures calculated here, although there is a topside enhancement in electron density that remains unexplained by ionospheric calculations that include photochemistry and plasma diffusion. Finally, parameterizations of the heating rate from photoelectrons and secondary electrons to thermal, ambient electrons have been developed. They may apply for other conditions at Saturn and possibly at other giant planets and exoplanets as well.

  12. TRIO (Triplet Ionospheric Observatory) Mission

    NASA Astrophysics Data System (ADS)

    Lee, D.; Seon, J.; Jin, H.; Kim, K.; Lee, J.; Jang, M.; Pak, S.; Kim, K.; Lin, R. P.; Parks, G. K.; Halekas, J. S.; Larson, D. E.; Eastwood, J. P.; Roelof, E. C.; Horbury, T. S.

    2009-12-01

    Triplets of identical cubesats will be built to carry out the following scientific objectives: i) multi-observations of ionospheric ENA (Energetic Neutral Atom) imaging, ii) ionospheric signature of suprathermal electrons and ions associated with auroral acceleration as well as electron microbursts, and iii) complementary measurements of magnetic fields for particle data. Each satellite, a cubesat for ion, neutral, electron, and magnetic fields (CINEMA), is equipped with a suprathermal electron, ion, neutral (STEIN) instrument and a 3-axis magnetometer of magnetoresistive sensors. TRIO is developed by three institutes: i) two CINEMA by Kyung Hee University (KHU) under the WCU program, ii) one CINEMA by UC Berkeley under the NSF support, and iii) three magnetometers by Imperial College, respectively. Multi-spacecraft observations in the STEIN instruments will provide i) stereo ENA imaging with a wide angle in local times, which are sensitive to the evolution of ring current phase space distributions, ii) suprathermal electron measurements with narrow spacings, which reveal the differential signature of accelerated electrons driven by Alfven waves and/or double layer formation in the ionosphere between the acceleration region and the aurora, and iii) suprathermal ion precipitation when the storm-time ring current appears. In addition, multi-spacecraft magnetic field measurements in low earth orbits will allow the tracking of the phase fronts of ULF waves, FTEs, and quasi-periodic reconnection events between ground-based magnetometer data and upstream satellite data.

  13. 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.

  14. An empirical probability density distribution of planetary ionosphere storms with geomagnetic precursors

    NASA Astrophysics Data System (ADS)

    Gulyaeva, Tamara; Stanislawska, Iwona; Arikan, Feza; Arikan, Orhan

    The probability of occurrence of the positive and negative planetary ionosphere storms is evaluated using the W index maps produced from Global Ionospheric Maps of Total Electron Content, GIM-TEC, provided by Jet Propulsion Laboratory, and transformed from geographic coordinates to magnetic coordinates frame. The auroral electrojet AE index and the equatorial disturbance storm time Dst index are investigated as precursors of the global ionosphere storm. The superposed epoch analysis is performed for 77 intense storms (Dst≤-100 nT) and 227 moderate storms (-100ionosphere storm, versus AE index and Dst index. It is found that AE index better suits to serve as a precursor of the ionosphere storm than Dst index with onset of the average auroral AE storm occurring 6 h before the equatorial Dst storm onset for intense storms and 3 h in advance of moderate Dst storm. The similar space zones advancement of the ionosphere storm is observed with W index (pW+ and pW-) depicting maximum localized in the polar magnetic zone and minimum at magnetic equator. An empirical relation for pW+ and pW- with AE storm precursor is derived which enables the probability of occurrence of the ionosphere storm to be predicted with leading time of 1-2 h for the positive ionosphere storm and 9-10 h for the negative ionosphere storm. The ionosphere storm probability model is validated using data for 2 intense and 20

  15. 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.

  16. Medium-scale traveling ionospheric disturbances by three-dimensional ionospheric GPS tomography

    NASA Astrophysics Data System (ADS)

    Chen, C. H.; Saito, A.; Lin, C. H.; Yamamoto, M.; Suzuki, S.; Seemala, G. K.

    2016-02-01

    In this study, we develop a three-dimensional ionospheric tomography with the ground-based global position system (GPS) total electron content observations. Because of the geometric limitation of GPS observation path, it is difficult to solve the ill-posed inverse problem for the ionospheric electron density. Different from methods given by pervious studies, we consider an algorithm combining the least-square method with a constraint condition, in which the gradient of electron density tends to be smooth in the horizontal direction and steep in the vicinity of the ionospheric F2 peak. This algorithm is designed to be independent of any ionospheric or plasmaspheric electron density models as the initial condition. An observation system simulation experiment method is applied to evaluate the performance of the GPS ionospheric tomography in detecting ionospheric electron density perturbation at the scale size of around 200 km in wavelength, such as the medium-scale traveling ionospheric disturbances.

  17. Investigations of magnetosphere-ionosphere coupling relevant to operational systems. Final scientific report, 1984-1987

    SciTech Connect

    Meng, C.I.; Newell, P.T.

    1988-02-01

    Important advances were made in understanding the dynamics of the magnetosphere and its coupling to the ionosphere. Significant progress was made in the areas of polar cusp precipitation and dynamics; dayside auroral morphology and auroral boundary dynamics; polar rain; the quiescent polar cap; the physics of impulsive injection phenomena; and problems of global magnetospheric plasma transport.

  18. Federal Funding and Knowledge Growth in Ionospheric Physics, 1945-81.

    ERIC Educational Resources Information Center

    Gillmor, C. Stewart

    1986-01-01

    Presents a historical overview of developments in ionospheric physics and examines relationships between federal funding and knowledge growth in this field. Summarizes the views of ionsphere researchers on funding, the role of funding program managers, and the nature of funding agencies. Reviews advancements related to entrepreneurs and resources…

  19. Regional Precipitation Forecast with Atmospheric InfraRed Sounder (AIRS) Profile Assimilation

    NASA Technical Reports Server (NTRS)

    Chou, S.-H.; Zavodsky, B. T.; Jedloved, G. J.

    2010-01-01

    Advanced technology in hyperspectral sensors such as the Atmospheric InfraRed Sounder (AIRS; Aumann et al. 2003) on NASA's polar orbiting Aqua satellite retrieve higher vertical resolution thermodynamic profiles than their predecessors due to increased spectral resolution. Although these capabilities do not replace the robust vertical resolution provided by radiosondes, they can serve as a complement to radiosondes in both space and time. These retrieved soundings can have a significant impact on weather forecasts if properly assimilated into prediction models. Several recent studies have evaluated the performance of specific operational weather forecast models when AIRS data are included in the assimilation process. LeMarshall et al. (2006) concluded that AIRS radiances significantly improved 500 hPa anomaly correlations in medium-range forecasts of the Global Forecast System (GFS) model. McCarty et al. (2009) demonstrated similar forecast improvement in 0-48 hour forecasts in an offline version of the operational North American Mesoscale (NAM) model when AIRS radiances were assimilated at the regional scale. Reale et al. (2008) showed improvements to Northern Hemisphere 500 hPa height anomaly correlations in NASA's Goddard Earth Observing System Model, Version 5 (GEOS-5) global system with the inclusion of partly cloudy AIRS temperature profiles. Singh et al. (2008) assimilated AIRS temperature and moisture profiles into a regional modeling system for a study of a heavy rainfall event during the summer monsoon season in Mumbai, India. This paper describes an approach to assimilate AIRS temperature and moisture profiles into a regional configuration of the Advanced Research Weather Research and Forecasting (WRF-ARW) model using its three-dimensional variational (3DVAR) assimilation system (WRF-Var; Barker et al. 2004). Section 2 describes the AIRS instrument and how the quality indicators are used to intelligently select the highest-quality data for assimilation

  20. Effects of a strong ICME on the Martian ionosphere as detected by Mars Express and Mars Odyssey

    NASA Astrophysics Data System (ADS)

    Morgan, D. D.; Diéval, C.; Gurnett, D. A.; Duru, F.; Dubinin, E. M.; Fränz, M.; Andrews, D. J.; Opgenoorth, H. J.; Uluşen, D.; Mitrofanov, I.; Plaut, J. J.

    2014-07-01

    We present evidence of a substantial ionospheric response to a strong interplanetary coronal mass ejection (ICME) detected by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on board the Mars Express (MEX) spacecraft. A powerful ICME impacted the Martian ionosphere beginning on 5 June 2011, peaking on 6 June, and trailing off over about a week. This event caused a strong response in the charged particle detector of the High-Energy Neutron Detector (HEND) on board the Odyssey spacecraft. The ion mass spectrometer of the Analyzer of Space Plasmas and Energetic Atoms instrument on MEX detected an increase in background counts, simultaneous with the increase seen by HEND, due to the flux of solar energetic particles (SEPs) associated with the ICME. Local densities and magnetic field strengths measured by MARSIS and enhancements of 100 eV electrons denote the passing of an intense space weather event. Local density and magnetosheath electron measurements and remote soundings show compression of ionospheric plasma to lower altitudes due to increased solar wind dynamic pressure. MARSIS topside sounding of the ionosphere indicates that it is extended well beyond the terminator, to about 116° solar zenith angle, in a highly disturbed state. This extension may be due to increased ionization due to SEPs and magnetosheath electrons or to plasma transport across the terminator. The surface reflection from both ionospheric sounding and subsurface modes of the MARSIS radar was attenuated, indicating increased electron content in the Mars ionosphere at low altitudes, where the atmosphere is dense.

  1. Solitons versus parametric instabilities during ionospheric heating

    NASA Technical Reports Server (NTRS)

    Nicholson, D. R.; Payne, G. L.; Downie, R. M.; Sheerin, J. P.

    1984-01-01

    Various effects associated with ionospheric heating are investigated by numerically solving the modified Zakharov (1972) equations. It is shown that, for typical ionospheric parameters, the modulational instability is more important than the parametric decay instability in the spatial region of strongest heater electric field. It is concluded that the modulational instability leads to the formation of solitons, as originally predicted by Petviashvili (1976).

  2. 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.

  3. Ionospheric disturbances produced by powerful explosives

    NASA Astrophysics Data System (ADS)

    Nagorskii, P. M.; Tarashchuk, Yu. E.

    1992-09-01

    Results of a study of wave-like ionospheric disturbances initiated by powerful explosives are presented and analyzed. Three types of wave processes with differing physical natures which propagate in the upper atmosphere and ionosphere to distances of thousands of kilometers are distinguished. The effect of shock-acoustic waves on indirect short wave radio propagation is considered.

  4. Trade-off studies of a hyperspectral infrared sounder on a geostationary satellite.

    PubMed

    Wang, Fang; Li, Jun; Schmit, Timothy J; Ackerman, Steven A

    2007-01-10

    Trade-off studies on spectral coverage, signal-to-noise ratio (SNR), and spectral resolution for a hyperspectral infrared (IR) sounder on a geostationary satellite are summarized. The data density method is applied for the vertical resolution analysis, and the rms error between true and retrieved profiles is used to represent the retrieval accuracy. The effects of spectral coverage, SNR, and spectral resolution on vertical resolution and retrieval accuracy are investigated. The advantages of IR and microwave sounder synergy are also demonstrated. When focusing on instrument performance and data processing, the results from this study show that the preferred spectral coverage combines long-wave infrared (LWIR) with the shorter middle-wave IR (SMidW). Using the appropriate spectral coverage, a hyperspectral IR sounder with appropriate SNR can achieve the required science performance (1 km vertical resolution, 1 K temperature, and 10% relative humidity retrieval accuracy). The synergy of microwave and IR sounders can improve the vertical resolution and retrieval accuracy compared to either instrument alone. PMID:17268565

  5. Evolution of Satellite Imagers and Sounders for Low Earth Orbit and Technology Directions at NASA

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; McClain, Charles R.

    2010-01-01

    Imagers and Sounders for Low Earth Orbit (LEO) provide fundamental global daily observations of the Earth System for scientists, researchers, and operational weather agencies. The imager provides the nominal 1-2 km spatial resolution images with global coverage in multiple spectral bands for a wide range of uses including ocean color, vegetation indices, aerosol, snow and cloud properties, and sea surface temperature. The sounder provides vertical profiles of atmospheric temperature, water vapor cloud properties, and trace gases including ozone, carbon monoxide, methane and carbon dioxide. Performance capabilities of these systems has evolved with the optical and sensing technologies of the decade. Individual detectors were incorporated on some of the first imagers and sounders that evolved to linear array technology in the '80's. Signal-to-noise constraints limited these systems to either broad spectral resolution as in the case of the imager, or low spatial resolution as in the case of the sounder. Today's area 2-dimensional large format array technology enables high spatial and high spectral resolution to be incorporated into a single instrument. This places new constraints on the design of these systems and enables new capabilities for scientists to examine the complex processes governing the Earth System.

  6. Determination of film processing specifications for the Apollo 17 S-209 lunar sounder experiment

    NASA Technical Reports Server (NTRS)

    Weinstein, M. S.

    1972-01-01

    The lunar sounder is described as a radar system operating at carrier frequencies of 5, 15, and 150 MHz. The radar echoes are recorded onto Kodak type S0-394 film through the use of an optical recorder utilizing a cathode ray tube as the exposing device. A processing configuration is determined with regard to linearity, dynamic range, and noise.

  7. High-powered Radar Sounders for the Investigation of Jupiter's Icy Moons

    NASA Technical Reports Server (NTRS)

    Safaeinili, A.; Rodriguez, E.; Edelstein, Wendy

    2003-01-01

    This talk will address the main drivers in the design of a radar sounder for the JIMO mission and provide a potential solution that will optimize the chances of success in the detection of ice/water interface and sub-surface stratigraphy.

  8. Shallow scattering layer in the subarctic pacific ocean: detection by high-frequency echo sounder.

    PubMed

    Barraclough, W E; Lebrasseur, R J; Kennedy, O D

    1969-10-31

    Shallow scattering layers consisting mainly of Calanus cristatus were detected on a trans-Pacific crossing to depths of 60 meters with a high-frequency echo sounder. Biomass estimates of these layers indicate concentrations of zoo-plankton that are greater and more extensive than previously reported in the open ocean. PMID:17778203

  9. Estimation of dielectric constant of lunar material by HF sounder observation

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Ono, T.

    Space borne radio sounding observation has been one of indispensable items in planetary missions An HF sounder Lunar Radar Sounder LRS will be onboard SELENE a lunar exploration program of Japan in 2007 Its primary objective is subsurface geologic structure of the Moon Especially mare regions are of strong interest of investigators because of its relatively smooth surface it is thought that smooth surface allows us to see subsurface feature with less difficulty However even if a clear subsurface image is obtained the data does not provide us with quantitative information unless the dielectric constant of the lunar subsurface material We propose a technique to estimate the dielectric constant of lunar material that utilizes HF sounder data of closely located multiple orbits The technique is applied to SAR images that are produced from HF sounder data and stands on the fact that the apparent position of subsurface object varies as a function of the dielectric constant of subsurface material Assuming a uniform subsurface material the displacement of images of a subsurface target should be consistent with that of observation orbits if the correct dielectric constant of the subsurface material is assumed A numerical model on geometrical optics estimates that the proposed technique requires a synthetic aperture larger than about 50km provided that the orbit altitude is 100km subsurface target depth is a few km and that the observation frequency is 5MHz with 2MHz bandwidth Some laboratory experiments were conducted to demonstrate validity of the

  10. High Resolution Infrared Radiation Sounder (HIRS) for the Nimbus F Spacecraft

    NASA Technical Reports Server (NTRS)

    Koenig, E. W.

    1975-01-01

    Flown on Nimbus F in June 1975, the high resolution infrared radiation sounder (HIRS) scans with a geographical resolution of 23KM and samples radiance in seventeen selected spectral channels from visible (.7 micron) to far IR (15 micron). Vertical temperature profiles and atmospheric moisture content can be inferred from the output. System operation and test results are described.

  11. Driving mechanism of the nightside ionospheric convection

    NASA Astrophysics Data System (ADS)

    Kikuchi, T.

    2001-12-01

    Magnetometer and SuperDARN observations provided evidence of the instantaneous reaction of ionospheric convection on the dayside and nightside. The AMIE analyses revealed that the potential pattern did not move but remained nearly at fixed locations. SuperDARN observations demonstrated that the plasma motion in the nightside ionosphere was intensified immediately after the motion of dayside ionospheric plasma was intensified within a resolution of the measurement (2 min). The convection in the night-side polar ionosphere would cause the plasma convection in the near-earth magnetotail. In the companion paper (Hashimoto and Kikuchi, this meeting) we demonstrate that the growth phase signature at the geosynchronous orbit and the ground magnetic signatures of the partial ring currents developed several minutes after the magnetic reconnection at the dayside magnetopause. These results suggest that the electric field responsible for the convection in the near-Earth magnetotail propagated from the night-side polar ionosphere after having propagated from the magnetosphere to the polar ionosphere on the dayside. In order to explain the quick response of the nightside ionospheric convection, we examine possible propagation modes that could transmit the convection electric field from the dayside outer magnetosphere to the nightside ionosphere. The magnetospheric convection may be generated either by accumulation of the FTEs or by the dynamo action in the cusp and the HLBL. In either case, the electric field propagates from the dayside magnetosphere to the nightside ionosphere within a few minutes. One possible propagation mode would be the magnetosonic wave propagating across the geomagnetic field and the other is the shear Alfvén mode propagating parallel to the geomagnetic field. The magnetosonic waves would be totally reflected at the ionosphere and the resultant electric field would be vanished almost completely. On the other hand, the convective motion of the plasma can

  12. 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.

  13. Methods of alleviation of ionospheric scintillation effects on digital communications

    NASA Technical Reports Server (NTRS)

    Massey, J. L.

    1974-01-01

    The degradation of the performance of digital communication systems because of ionospheric scintillation effects can be reduced either by diversity techniques or by coding. The effectiveness of traditional space-diversity, frequency-diversity and time-diversity techniques is reviewed and design considerations isolated. Time-diversity signaling is then treated as an extremely simple form of coding. More advanced coding methods, such as diffuse threshold decoding and burst-trapping decoding, which appear attractive in combatting scintillation effects are discussed and design considerations noted. Finally, adaptive coding techniques appropriate when the general state of the channel is known are discussed.

  14. Vertical and oblique ionospheric soundings over a very long multihop HF radio link from polar to midlatitudes: Results and relationships

    NASA Astrophysics Data System (ADS)

    Vilella, C.; Miralles, D.; Altadill, D.; Acosta, F.; Solé, J. G.; Torta, J. M.; Pijoan, J. L.

    2009-04-01

    A vertical incidence sounder (VIS) was installed at the Spanish Antarctic Base (62.7°S, 299.6°E) during the Antarctic summer survey 2004-2005. In addition, an oblique sounding (OS) system for HF communications between Antarctica and Spain (12,700 km) has been operated during the Antarctic summers since December 2003. OS results are compared to Rec533 model and to VIS data obtained from stations located along the radio path, including VIS stations at the emitter and receiver sites. The results presented in this paper show the potential of this infrastructure for ionospheric monitoring and research purposes at and from polar regions. The results also show that relevant information (e.g., maximum received frequency) of very long range radio links can be obtained from appropriate VIS stations along the path.

  15. 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.

  16. 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.

  17. 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

  18. Determination of travelling ionospheric disturbances

    NASA Technical Reports Server (NTRS)

    Degenhardt, W.; Hartmann, G. H.; Davies, K.

    1978-01-01

    A total of 35 days of Faraday rotation data was obtained from the ATS-6 radio beacon experiment operating with the closely spaced network of Elbert, Table Mountain, and Fort Morgan. The 140-MHz Faraday bandpass data are uncorrelated in the transmission range from 8 to 45 minutes. There are distinct, well correlated, and time-displaced maxima and minima that allow the calculation of the speed and direction of horizontal motions of plane fronts of disturbances in the ionosphere. For some selected events, velocities between 88 and 278 m/sec were obtained.

  19. 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

  20. Guided radio-wave propagation in the equatorial ionosphere according to the topside sounding onboard Interkosmos-19

    NASA Astrophysics Data System (ADS)

    Karpachev, A. T.; Zhbankov, G. A.; Kuleshova, V. P.; Telegin, V. A.

    2014-12-01

    In addition to normal vertical-incident ionogram traces, strongly remote (up to 2000 km) traces of HF-radio-signal reflections observed on topside-sounder ionograms of the Interkosmos-19 satellite obtained in the equatorial ionosphere are presented. Such traces are connected with waveguides (ducts). These waveguides are field-aligned irregularities of the ionospheric plasma with electron density depletions of a few percent and cross-field dimension of a few to several kilometers. Ray tracing confirms this supposition and allows an estimate of typical waveguide parameters: diameter ≤10-15 km and amplitude |ΔN/N|≥10%, where N is the electron density. The waveguide traces usually start at the cutoff frequencies of the main traces. However, sometimes they begin at much lower frequencies which indicates the satellite was transitioning through an equatorial plasma bubble during the recording of the ionogram. The X-mode of ducted echoes is more distinct then the O-mode. Only one ducted trace is usually observed on the Interkosmos-19 ionograms; a second conjugate trace is rarely recorded. The same is true for combination modes which is a combination of an oblique-incidence and guided propagation. Waveguides are observed at all heights of Interkosmos-19 (500-1000 km) inside the equatorial anomaly region (from -40° to +40° Dip). Waveguides are usually associated with other irregularities of various sizes in the equatorial ionosphere, some of which cause additional traces and spread F on the topside-sounding ionograms. Ducted-echo characteristics observed with Interkosmos-19 are different from those observed earlier with the Alouette and ISIS satellites. This difference is discussed. It is shown that the ionospheric plasma irregularities responsible for the waveguides are observed much more often during nighttime than during daytime.

  1. 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.

  2. Forecasting foF2 and MUF(3000)F2 ionospheric characteristics - A challenging space weather frontier

    NASA Astrophysics Data System (ADS)

    Cander, Ljiljana R.

    2015-11-01

    There is a strong space weather need to forecast the daily and hourly variations in ionospheric characteristics that occur within the ionosphere-thermosphere (I-T) system. A number of different models and techniques has been developed for that purpose. Many of these models and techniques can provide a reasonable agreement with the observational data, at least during geomagnetically quiet times. Forecasting ionospheric characteristics during disturbed periods that accompany space weather events is yet more difficult. Examples of two types of relatively simple solutions the space weather community can use in its attempt at short-term (1-h to 24-h in advance) and long-term (few days) ionosphere-thermosphere (I-T) forecasting are given in terms of two important ionosonde characteristics foF2 and MUF(3000)F2.

  3. 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.

  4. F-region ionospheric perturbations in the low-latitude ionosphere during the geomagnetic storm of 25-27 August 1987

    NASA Astrophysics Data System (ADS)

    Pavlov, A.; Fukao, S.; Kawamura, S.

    2004-10-01

    We have presented a comparison between the modeled NmF2 and hmF2, and NmF2 and hmF2 which were observed at the equatorial anomaly crest and close to the geomagnetic equator simultaneously by the Akita, Kokubunji, Yamagawa, Okinawa, Manila, Vanimo, and Darwin ionospheric sounders and by the middle and upper atmosphere (MU) radar (34.85° N, 136.10° E) during the 25-27 August 1987 geomagnetically storm-time period at low solar activity near 201°, geomagnetic longitude. A comparison between the electron and ion temperatures measured by the MU radar and those produced by the model of the ionosphere and plasmasphere is presented. The corrections of the storm-time zonal electric field, EΛ, from 16:30 UT to 21:00 UT on 25 August bring the modeled and measured hmF2 into reasonable agreement. In both hemispheres, the meridional neutral wind, W, taken from the HWW90 wind model and the NRLMSISE-00 neutral temperature, Tn, and densities are corrected so that the model results agree with the ionospheric sounders and MU radar observations. The geomagnetic latitude variations in NmF2 on 26 August differ significantly from those on 25 and 27 August. The equatorial plasma fountain undergoes significant inhibition on 26 August. This suppression of the equatorial anomaly on 26 August is not due to a reduction in the meridional component of the plasma drift perpendicular to the geomagnetic field direction, but is due to the action of storm-time changes in neutral winds and densities on the plasma fountain process. The asymmetry in W determines most of the north-south asymmetry in hmF2 and NmF2 on 25 and 27 August between about 01:00-01:30 UT and about 14:00 UT when the equatorial anomaly exists in the ionosphere, while asymmetries in W, Tn, and neutral densities relative to the geomagnetic equator are responsible for the north-south asymmetry in NmF2 and hmF2 on 26 August. A theory of the primary mechanisms causing the morning and evening peaks in the electron temperature, Te, is

  5. 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

  6. Investigating Solar Wind-Magnetosphere-Ionosphere Coupling with SuperDARN and AMPERE

    NASA Astrophysics Data System (ADS)

    Milan, S. E.; Coxon, J.; Imber, S. M.; Clausen, L.; Korth, H.; Anderson, B. J.

    2013-12-01

    The dynamics of the Earth's plasma environment are driven by coupling between the solar wind, with its embedded interplanetary magnetic field, and the magnetosphere through magnetic reconnection occurring at the magnetopause. Terrestrial magnetic field lines which are connected to interplanetary space in this way are subsequently released by magnetic reconnection occurring in the magnetotail. These two processes lead to increases and decreases in the proportion of the terrestrial flux that is open, as observed in changes in the latitude of the auroral zones. A circulation of plasma and magnetic flux is effected, the Dungey cycle, with a sympathetic plasma convection signature in the ionosphere. In this talk we review recent advances of our understanding of the coupling process, provided by measurements of ionospheric convection with the Super Dual Auroral Radar Network (SuperDARN) and the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) which measures the coupling currents that transfer stress from the magnetosphere into the ionosphere.

  7. Challenges for Future UV Imaging of the Earth's Ionosphere and High Latitude Regions

    NASA Technical Reports Server (NTRS)

    Spann, James

    2006-01-01

    Large scale imaging of Geospace has played a significant role in the recent advances in the comprehension of the coupled Solar-Terrestrial System. The Earth's ionospheric far ultraviolet emissions provide a rich tapestry of observations that play a key role in sorting out the dominant mechanisms and phenomena associated with the coupling of the ionosphere and magnetosphere (MI). The MI coupling is an integral part of the Solar-Terrestrial and as such, future observations in this region should focus on understanding the coupling and the impact of solar variability. This talk will focus on the outstanding problems associated with the coupled Solar-Terrestrial system that can be best addressed using far ultraviolet imaging of the Earthls ionosphere. Challenges of global scale imaging and high-resolution imaging will be discussed and how these are driven by unresolved compelling science questions of magnetospheric configuration, and auroral dynamics.

  8. A system definition study for the Advanced Meteorological Temperature Sounder (AMTS)

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The functional requirements of Exhibit A (11) were used as the baseline for the conceptual design of a fixed grating out of plane multidetector spectrometer for the Space Shuttle application. Because the grating instrument would be large and the 28 element detector array would be difficult to cool radiatively from a free flying spacecraft and because increasing the spectral resolution of the grating instrument would be difficult in an instrument of reasonable size, a parallel study of a Nichelson interferometer spectrometer was undertaken. This type of instrument offers compact size, fewer detectors to cool, and the possibility of increased spectral resolution. The design and performance parameters of both the grating and interferometer approaches are described. The tradeoffs involved in comparing the two systems for sounding applications are discussed.

  9. Comparison of the IPS HF Skywave Propagation Model With Ionospheric Sounding Data

    NASA Astrophysics Data System (ADS)

    Neudegg, D.; Layoun, M.; Patterson, G.; Caruana, J.

    2005-12-01

    The availability of radio sounding data through the ionosphere, particularly oblique paths with spaced transmitter and receiver, has allowed testing of the IPS propagation model. The model is at the core of Space Weather prediction systems in the Regional Warning Center (RWC), the Advanced Stand Alone Prediction Service (ASAPS) software used worldwide and the high-frequency (HF) system planning facility used in a consultancy role to determine the coverage and availability of skywave communications for over the horizon (OTH) communication or surveillance networks. The ionospheric sounding using the IPSNET array, particularly an oblique Trans-Tasman path between New Zealand and the east coast of Australia, indicates the usable HF frequency range supported for propagation by the ionosphere. The maximum first-hop oblique frequency may be compared with that produced from real time vertical radio sounding and converted to an oblique equivalent via the propagation model. The relation between the observed and modeled data is examined as a function of Space Weather proxies of ionospheric and solar activity (e.g. the T index), local time and the ionospheric gradient between the transmitter and receiver.

  10. Nighttime Cirrus Detection using Atmospheric Infrared Sounder Window Channels and Total Column Water Vapor

    NASA Technical Reports Server (NTRS)

    Kahn, Brian H.; Liou, Kuo Nan; Lee, Sung-Yung; Fishbein, Evan F.; DeSouza-Machado, Sergio; Eldering, Annmarie; Fetzer, Eric J.; Hannon, Scott E.; Strow, L. Larrabee

    2005-01-01

    A method of cirrus detection at nighttime is presented that utilizes 3.8 and 10.4 (micro)m infrared (IR) window brightness temperature differences (dBT) and total column precipitable water (PW) measurements. This technique is applied to the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit A (AMSU-A) instrument suite on board EOS-Aqua, where dBT is determined from sets of carefully selected AIRS window channels, while PW is derived from the synergistic AIRS and AMSU-A water vapor retrievals. Simulated and observed dBT for a particular value of PW are not constant; several physical factors impact dBT, including the variability in temperature and relative humidity profiles, surface emissivity, instrument noise, and skin/ near-surface air temperature differences. We simulate clear-sky dBT over a realistic range of PWs using 8350 radiosondes that have varying temperature and relative humidity profiles. Thresholds between cloudy and uncertain sky conditions are derived once the scatter in the clear-sky dBT is determined. Simulations of optically thin cirrus indicate that this technique is most sensitive to cirrus optical depth in the 10 (micro)m window of 0.1-0.15 or greater over the tropical and subtropical oceans, where surface emissivity and skin/near-surface air temperature impacts on the IR radiances are minimal. The method at present is generally valid over oceanic regions only, specifically, the tropics and subtropics. The detection of thin cirrus, and other cloud types, is validated using observations at the Atmospheric Radiation Measurement (ARM) program site located at Manus Island in the tropical western Pacific for 89 coincident EOS-Aqua overpasses. Even though the emphasis of this work is on the detection of thin cirrus at nighttime, this technique is sensitive to a broad cloud morphology. The cloud detection technique agrees with ARM-detected clouds 82-84% of the time, which include thin cirrus, as well as other cloud types. Most of

  11. Characterization and validation of methane products from the Atmospheric Infrared Sounder (AIRS)

    NASA Astrophysics Data System (ADS)

    Xiong, Xiaozhen; Barnet, Chris; Maddy, Eric; Sweeney, Colm; Liu, Xingpin; Zhou, Lihang; Goldberg, Mitch

    2008-09-01

    This paper presents the characterization and validation of retrievals of atmospheric methane (CH4) vertical profiles by the Atmospheric Infrared Sounder (AIRS) on the EOS/Aqua platform. AIRS channels near 7.6 μm are used for CH4 retrieval, and they are most sensitive to the middle to upper troposphere, i.e., about 200-300 hPa in the tropics and 400-500 hPa in the polar region. The atmospheric temperature-humidity profiles, surface skin temperature, and emissivity required to derive CH4 are obtained from retrievals using separate AIRS channels and the Advanced Microwave Sounding Unit (AMSU). Comparison of AIRS retrieved profiles with some in situ aircraft CH4 profiles implied that the forward model used in the AIRS retrieval system V4.0 required a 2% increase in methane absorption coefficients for strong absorption channels, and this bias adjustment was implemented in the AIRS retrieval system V5.0. As a new operational product in V5.0, AIRS CH4 were validated using in situ aircraft observations at 22 sites of the NOAA Earth System Research Laboratory, Global Monitoring Division (NOAA/ESRL/GMD), ranging from the Arctic to the tropical South Pacific Ocean, but their altitudes are usually above 300 hPa. The results show the bias of the retrieved CH4 profiles for this version is -1.4˜0.1% and its RMS difference is about 0.5-1.6%, depending on altitude. These validation comparisons provide critical assessment of the retrieval algorithm and will continue using more in situ observations together with future improvement to the retrieval algorithm. AIRS CH4 products include not only the CH4 profile but also the information content. As examples, the products of AIRS CH4 in August 2004 and the difference of CH4 in May and September 2004 are shown. From these results a few features are evident: (1) a large AIRS CH4 plume southwest of the Tibetan plateau that may be associated with deep convection during the Asian summer monsoon; (2) high mixing ratios of AIRS CH4 in

  12. Global Assimilation of Ionospheric Measurements (GAIM)

    NASA Astrophysics Data System (ADS)

    Schunk, Robert W.; Scherliess, Ludger; Sojka, Jan J.; Thompson, Donald C.; Anderson, David N.; Codrescu, Mihail; Minter, Cliff; Fuller-Rowell, Timothy J.; Heelis, Roderick A.; Hairston, Marc; Howe, Bruce M.

    2004-02-01

    The ionosphere is a highly dynamic medium that exhibits weather disturbances at all latitudes, longitudes, and altitudes, and these disturbances can have detrimental effects on both military and civilian systems. In an effort to mitigate the adverse effects, we are developing a physics-based data assimilation model of the ionosphere and neutral atmosphere called the Global Assimilation of Ionospheric Measurements (GAIM). GAIM will use a physics-based ionosphere-plasmasphere model and a Kalman filter as a basis for assimilating a diverse set of real-time (or near real-time) measurements. Some of the data to be assimilated include in situ density measurements from satellites, ionosonde electron density profiles, occultation data, ground-based GPS total electron contents (TECs), two-dimensional ionospheric density distributions from tomography chains, and line-of-sight UV emissions from selected satellites. When completed, GAIM will provide specifications and forecasts on a spatial grid that can be global, regional, or local. The primary output of GAIM will be a continuous reconstruction of the three-dimensional electron density distribution from 90 km to geosynchronous altitude (35,000 km). GAIM also outputs auxiliary parameters, including NmF2, hmF2, NmE, hmE, and slant and vertical TEC. Furthermore, GAIM provides global distributions for the ionospheric drivers (neutral winds and densities, magnetospheric and equatorial electric fields, and electron precipitation patterns). In its specification mode, GAIM yields quantitative estimates for the accuracy of the reconstructed ionospheric densities.

  13. Mid-latitude Ionospheric HF Channel Reciprocity: Evidence from the Ionospheric Oblique Incidence Sounding Experiments

    NASA Astrophysics Data System (ADS)

    Zhou, Chen; Zhao, Zhengyu; Zhang, Yuannong

    The mid-latitude ionospheric HF channel reciprocity is studied in this paper through theoret-ical considerations and ionospheric oblique incidence sounding experiments. The reciprocity of ionospheric HF channel experiments were carried out by using two identical Wuhan Iono-spheric Oblique Incidence Sounding Systems (WIOISS) located in Wuhan (30° 32N, 114° 21E) and Wanning (18° 58N, 110° 31E) respectively. The comparisons of group distance and Doppler shift between Wuhan-Wanning and Wanning-Wuhan HF ionospheric propagation paths show that the reciprocity of ionospheric HF channel is satisfied to some extent. The group dis-tances of two paths are calculated by a 3-D ray tracing simulation as well. The theoretical and experimental results could be widely used for HF communication systems and sky wave over-the-horizon radar.

  14. Midlatitude ionospheric HF channel reciprocity: Evidence from the ionospheric oblique incidence sounding experiments

    NASA Astrophysics Data System (ADS)

    Zhou, Chen; Zhao, Zhengyu; Deng, Feng; Ni, Binbin; Chen, Gang

    2010-12-01

    Ionospheric HF channel reciprocity is investigated at middle latitudes on the basis of ionospheric oblique incidence sounding experiments. Two identical Wuhan Ionospheric Oblique Incidence Sounding Systems (WIOISS), located at Wuhan (30°32'N, 114°21'E) and Wanning (18°58'N, 110°31'E), are used to carry out the campaign. Comparisons of group distance and Doppler shift between Wuhan-Wanning and Wanning-Wuhan HF ionospheric propagation paths indicate that the reciprocity of the ionospheric HF channel is satisfied at midlatitude region. A 3-D ray tracing simulation is also implemented to evaluate the group distances of the two paths. Midlatitude ionospheric HF channel reciprocity, as verified both experimentally and theoretically in the present study, can be useful for HF communication systems and sky wave over-the-horizon radars.

  15. Ionospheric top side model ingesting observed STEC into an empirical ionospheric model

    NASA Astrophysics Data System (ADS)

    Gularte Scarone, A. E.; Brunini, C.; Meza, A. M.

    Several empirical models are currently used to describe the electron density distribution in the ionosphere The driving parameters used for the majority of these models are the electron density NmF2 and the height hmF2 of the peak Dual frequency ground GPS satellite observations provide estimates of the slant total electron content STEC that is the integral of the electron density along the ray-path of the signal In this contribution we present a method to improve the ionospheric top side model ingesting the observed STEC into an empirical ionospheric model and updating the climatological parameters to a better representation of the meteorological conditions of the ionosphere The analysis is done in periods with different levels of ionospheric activity during solstices or equinoxes and La Plata Ionospheric Model LPIM is used for computing 4-D free electron distribution

  16. Ionosphere monitoring using NOAA's CORS network

    NASA Astrophysics Data System (ADS)

    Smith, D.

    NOAA's National Geodetic Survey is currently engaged in research to use the CORS (Continuously Operating GPS Reference Stations) network to model the ionosphere over the conterminous United States and surrounding areas. The CORS network consists of over 700 stations that continuously collect data from all GPS satellite vehicles in view; these data are available free of charge for (predominantly) positioning applications. However, the nature of the network makes it an excellent tool for continuously monitoring the nature of the ionosphere over and near the conterminous United States. From the standpoint of geodesy, the ionosphere effect is generally considered a nuisance parameter: that should be modeled and removed so that the ambiguity in dual frequency GPS carrier-phase signals may be resolved and accurate positions determined. As such, the initial direction of this research is toward modeling the ionosphere for geodetic use, using a single-layer "shell model". The results presented here show the first steps toward accurately modeling the ionosphere through the CORS network, in terms of absolute (non-differential) Total Electron Content Units (TECUs) through an innovative cross-over adjustment of "tracks". Each track is made by the intersection of a satellite/receiver vector with the ionosphere shell as the satellite moves overhead. Results of the initial research in applying the modeled ionosphere toward ambiguity resolution will be discussed. Limitations of using the one-dimensional shell will also be presented. Future plans for creating a time-stream of the ionosphere, increasing the complexity beyond the shell model, and applications toward nowcast and forecast of the ionosphere, will also be discussed.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Artificial periodic irregularities in the auroral ionosphere

    NASA Astrophysics Data System (ADS)

    Rietveld, M. T.; Turunen, E.; Matveinen, H.; Goncharov, N. P.; Pollari, P.

    1996-12-01

    Artificial periodic irregularities (API) are produced in the ionospheric plasma by a powerful standing electromagnetic wave reflected off the F region. The resulting electron-density irregularities can scatter other high-frequency waves if the Bragg scattering condition is met. Such measurements have been performed at mid-latitudes for two decades and have been developed into a useful ionospheric diagnostic technique. We report here the first measurements from a high-latitude station, using the EISCAT heating facility near Tromsø, Norway. Both F-region and lower-altitude ionospheric echoes have been obtained, but the bulk of the data has been in the E and D regions with echoes extending down to 52-km altitude. Examples of API are shown, mainly from the D region, together with simultaneous VHF incoherent-scatter-radar (ISR) data. Vertical velocities derived from the rate of phase change during the irregularity decay are shown and compared with velocities derived from the ISR. Some of the API-derived velocities in the 75-115-km height range appear consistent with vertical neutral winds as shown by their magnitudes and by evidence of gravity waves, while other data in the 50-70-km range show an unrealistically large bias. For a comparison with ISR data it has proved difficult to get good quality data sets overlapping in height and time. The initial comparisons show some agreement, but discrepancies of several metres per second do not yet allow us to conclude that the two techniques are measuring the same quantity. The irregularity decay time-constants between about 53 and 70 km are compared with the results of an advanced ion-chemistry model, and height profiles of recorded signal power are compared with model estimates in the same altitude range. The calculated amplitude shows good agreement with the data in that the maximum occurs at about the same height as that of the measured amplitude. The calculated time-constant agrees very well with the data below 60 km but

  2. Low Latitude Ionosphere Measurements by the Global-scale Observations of the Limb and Disk (GOLD) Mission

    NASA Astrophysics Data System (ADS)

    Eastes, R. W.; Anderson, D. N.; McClintock, W. E.; Aksnes, A.; Andersson, L.; Burns, A. G.; Budzien, S. A.; Codrescu, M. V.; Daniell, R. E.; Dymond, K. F.; England, S. L.; Eparvier, F. J.; Harvey, J. E.; Immel, T. J.; Krywonos, A.; Lankton, M. R.; Lumpe, J. D.; Richmond, A. D.; Rusch, D. W.; Siegmund, O. H.; Solomon, S. C.; Strickland, D. J.; Woods, T. N.

    2008-12-01

    The GOLD Mission of Opportunity will provide answers to key elements of an overarching question for Heliophysics science: what is the global-scale response of the thermosphere and ionosphere to forcing in the integrated Sun-Earth system? GOLD will perform remote-sensing measurements of the Earth's thermosphere and ionosphere, using an ultraviolet imager on board a commercial, geosynchronous satellite. The resulting measurements of the electron densities in the nighttime ionosphere as well as the neutral composition and temperature in the thermosphere, when combined with current modeling capabilities, will advance our understanding of Thermosphere-Ionosphere (T-I) forcing. GOLD will provide the first global- scale "snapshot" of temperature that can be compared with the coincident "snapshot" of composition changes to understand how these two major parameters simultaneously react to the various forcing mechanisms. GOLD will continue observing the same longitudes from the daytime into the night allowing the relationship between presunset conditions in the T-I system and the longitudinal dependence of variations in the ionosphere to be separated. One question that GOLD will address is: do vertical ion drifts, as manifested in the structure of the equatorial anomaly, affect the occurrence of ionospheric irregularities? Solar and geomagnetic forcing produces variations in the structure of the equatorial ionosphere at night (equatorial anomaly) and the occurrence of irregularities within the ionosphere. These ionospheric density variations, with scale sizes ranging from hundreds to tens of km, have profound effects on systems using radio frequencies. Irregularities at low latitudes are produced in the post-sunset ionosphere by the Rayleigh-Taylor (R-T) instability. The growth of these R-T instabilities into large-scale plasma bubbles has an optical signature and is the greatest source of ionospheric irregularities at low latitudes. Simulations of GOLD observations indicate

  3. Measurement of middle and upper atmospheric horizontal winds with a submillimeter/THz limb sounder: results from JEM/SMILES and simulation study for SMILES-2

    NASA Astrophysics Data System (ADS)

    Baron, Philippe; Manago, Naohiro; Ozeki, Hiroyuki; Yoshihisa, Irimajiri; Donal, Murtagh; Yoshinori, Uzawa; Satoshi, Ochiai; Masato, Shiotani; Makoto, Suzuki

    2016-04-01

    In a near future, ESA will launch the Atmospheric Dynamics Mission (ADM) equipped with a lidar for measuring tropospheric and lower stratospheric winds. NASA will continue a long-term series of upper atmospheric wind measurements (altitudes >80 km) with the new Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) on the Ionospheric Connection Explorer (ICON) satellite. No mission is planned to observe winds in the middle atmosphere (30-80 km), though they are recognized as essential parameters for understanding atmospheric dynamics and the vertical coupling between atmospheric regions. They are also promising data for improving long-term weather forecast and climate modelling. It has been demonstrated with the Superconducting Submillimeter Wave Limb Emission Sounder (SMILES, Oct 2009 - Apr 2010) that a 4-K cooled microwave radiometer can provide data to fill the altitude gap in the wind measurements. Its possible successor named SMILES-2, is being designed in Japan for the study of the middle and upper atmospheric chemistry and dynamics (O3, H2O, T, atomic O, OH, HO2, ClO, BrO, ...). If realized, the instrument will measure sub-millimeter and THz molecular spectral lines (616-150 μm) with high sensitivity and frequency resolution. The SMILES-2 characteristics are very well suited for horizontal wind observations between 20 km to more than 160 km. The best performances are found between 35-90 km where the retrieval precision is better than 3 m/s for a vertical resolution of 2-3 km [1]. In this presentation, we summarize the results obtained from SMILES and assess the measurement performances of SMILES-2 to measure horizontal winds. [1] P. Baron, N. Manago, H. Ozeki, Y. Irimajiri, D. Murtagh, Y. Uzawa, S. Ochiai, M. Shiotani, M. Suzuki: "Measurement of stratospheric and mesospheric winds with a SubMillimeter wave limb sounder: Results from JEM/SMILES and simulation study for SMILES-2"; Proc. of SPIE Remote sensing, 96390N-96390N-20

  4. 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.

  5. Global and Regional Seasonal Variability of Mid-Tropospheric CO2 as Measured by the Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Olsen, Edward T.; Nguyen, Hai

    2012-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the Earth Observing System (EOS) Aqua Spacecraft, launched on May 4, 2002 into a near polar sun-synchronous orbit. AIRS has 2378 infrared channels ranging from 3.7 ?m to 15.4 ?m and a 13.5 km footprint at nadir. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy on a global scale, as well as water vapor profiles and trace gas amounts for CO2, CO, SO2, O3 and CH4. AIRS CO2 climatologies have been shown to be useful for identifying anomalies associated with geophysical events such as El Nino-Southern Oscillation or Madden-Julian oscillation. In this study, monthly representations of mid-tropospheric CO2 are constructed from 10 years of AIRS Version 5 monthly Level 3 data. We compare the AIRS mid-tropospheric CO2 representations to ground-based measurements from the Scripps and National Oceanic and Atmospheric Administration Climate Modeling and Diagnostics Laboratory (NOAA CMDL) ground networks to better understand the phase lag of the CO2 seasonal cycle between the surface and middle troposphere. Results show only a small phase lag in the tropics that grows to approximately two months in the northern latitudes.

  6. Application of Spaceborne Infrared Atmospheric Sounder for Geosynchronous Earth Orbit (SIRAS-G) technology to future Earth science missions

    NASA Astrophysics Data System (ADS)

    Kampe, Thomas U.

    2008-04-01

    The Spaceborne Infrared Sounder for Geosynchronous Earth Orbit (SIRAS-G) was developed by Ball Aerospace & Technologies Corp (BATC) under NASA's 2002 Instrument Incubator Program. SIRAS-G was a technology development program focused on next-generation IR imaging spectrometers for sounding of the atmosphere. SIRAS-G demonstrated that the dispersive grating spectrometer is a suitable instrument architecture for this application. In addition to providing atmospheric temperature and water vapor profiles, SIRAS-G can provide trace gases concentrations, land and ocean surface temperatures and the IR mineral dust aerosol signature from satellite. The 3-year SIRAS-G IIP development effort included the successful cryogenic testing of the SIRAS-G laboratory demonstration spectrometer operating in the 2083 to 2994 cm -1 frequency range. The performance of the demonstration instrument has been quantified including measurement of keystone distortion, spectral smile, MTF, and the spectral response function (SRF). Development efforts associated with this advanced infrared spectrometer technology provides the basis for instrumentation to support future Earth science missions.

  7. Validation of the Atmospheric Infrared Sounder Water Vapor Retrievals Using Global Positioning System: Case Study in South Korea

    NASA Astrophysics Data System (ADS)

    Won, Jihye; Park, Kwan-Dong; Kim, Dusik; Ha, Jihyun

    2011-12-01

    The atmospheric infrared sounder (AIRS) sensor loaded on the Aqua satellite observes the global vertical structure of atmosphere and enables verification of the water vapor distribution over the entire area of South Korea. In this study, we performed a comparative analysis of the accuracy of the total precipitable water (TPW) provided as the AIRS level 2 standard retrieval product by Jet Propulsion Laboratory (JPL) over the South Korean area using the global positioning system (GPS) TPW data. The analysis TPW for the period of one year in 2008 showed that the accuracy of the data produced by the combination of the Advanced Microwave Sounding Unit sensor with the AIRS sensor to correct the effect of clouds (AIRS-X) was higher than that of the AIRS IR-only data (AIRS-I). The annual means of the root mean square error with reference to the GPS data were 5.2 kg/m2 and 4.3 kg/m2 for AIRS-I and AIRS-X, respectively. The accuracy of AIRS-X was higher in summer than in winter while measurement values of AIRS-I and AIRS-X were lower than those of GPS TPW to some extent.

  8. Temperature and Dust Profiles During the Martian Global Dust Storm in 2007 from Mars Climate Sounder Measurements

    NASA Astrophysics Data System (ADS)

    Kleinboehl, A.; Kass, D. M.; Schofield, J. T.; McCleese, D. J.

    2014-07-01

    In 2007 the Mars Climate Sounder observed a global dust storm on Mars. We will present results that show the development of the dust storm over time and the vertical structure of atmospheric temperature and dust.

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

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  10. 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.

  11. Artificial defocusing lens in ionosphere

    NASA Astrophysics Data System (ADS)

    Boyko, G. N.; Vaskov, V. V.; Golyan, S. F.; Gurevich, A. V.; Dimant, Y. S.; Zyuzkin, V. A.; Kim, V. Y.; Komrakov, G. P.; Lobacheviskiy, L. A.; Migulin, V. V.

    1984-10-01

    Strong defocusing of perturbing radio waves is detected, indicating the creation of an effective defocusing lens in the ionosphere. Modess in which there is not anomalous absorption are employed in order to isolate the defocusing effects unambiguously. The experimental setup incorporates a 300 MW SURG heating system with a narrow radiation pattern. The concentration perturbations are diagnosed in the vertical sounding mode at 8 frequencies by means of a Doppler system. The experimental results were obtained during May and July 1983 under daytime conditions. The amplitude and Doppler frequency shift behavior of the probe wave is analyzed, and the defocusing coefficient is computed as a function of the frequency of the probe wave and power of the heating wave. The artificial lens detected results in significant attenuation of radio waves passing through it.

  12. Auroral pulsations from ionospheric winds

    SciTech Connect

    Nakada, M.P. )

    1989-11-01

    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 Pederson 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.

  13. Ionospheric effects of supernova explosions

    NASA Astrophysics Data System (ADS)

    Edwards, P. J.

    Possible ionospheric effects of supernova explosions are considered, with special attention given to those of SN 1987a. Results are presented on the calculations of anticipated X-ray/UV flare parameters, including the shock temperature, the minimum flare duration, the average photon energy, and the shock-front travel time for a range of stellar radii bracketing SK 202-69, which was identified by White Malin (1987) as the progenitor star for SN 1987a. It is shown that the characteristics of the X-ray/UV flare are strongly influenced by the radius of the shock wave breakout, so that the flare from SN 1987a can be anticipated to have characteristics intermediate between those attributed to compact stars and stars with extended envelopes.

  14. 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.

  15. Investigation of ionospheric gradients for GAGAN application

    NASA Astrophysics Data System (ADS)

    Chandra, K. Ravi; Srinivas, V. Satya; Sarma, A. D.

    2009-05-01

    To cater to the needs of aviation applications, GPS Aided GEO Augmented Navigation (GAGAN) system is being implemented over the Indian region. The most prominent parameter affecting the navigation accuracy of GAGAN is ionospheric delay which is a function of TEC. In the equatorial and low latitude regions such as India, TEC is often quite high with large spatial gradients. Carrier phase data from the GAGAN network of Indian TEC Stations is used for estimating ionospheric gradients in multiple viewing directions. Rate of TEC (ROT) and Rate of TEC Index (ROTI) are calculated to identify the ionospheric gradients. Among the satellite signals arriving in multiple directions, the signals which suffer from severe ionospheric gradients are identified and avoided for improving GAGAN positional accuracy. The outcome of this paper will be helpful for improving GAGAN system performance.

  16. 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.

  17. Global ionospheric weather. Scientific report No. 2

    SciTech Connect

    Decker, D.T.; Doherty, P.H.

    1995-02-28

    Work on global F region modeling has consisted of participation in the Phillips Laboratory Low Latitude Ionospheric Tomography Campaign, testing of the Global Theoretical Ionospheric Model (GTIM), and testing of the Parameterized Ionospheric Model (PIM). Analysis of TEC data and comparisons with other ionospheric models have been successfully conducted and are ongoing. Analysis of GPS observations are also ongoing. Studies have been made concerning limitations in determining TEC from dual frequency GPS measurements as well as the statistics of time rate of change of TEC. Software has been developed to process RINEX formatted GPS data into TEC. Work comparing the aulthors electron proton H atom model to both observations and other models has been very successful. The authors have also successfully modeled the creation of boundary blobs using time varying convection to first create patches in the polar cap and then to transport and distort them into boundary blobs in the auroral region.

  18. Thermospheric storms and related ionospheric effects

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Spencer, N. W.

    1976-01-01

    A comparative study of thermospheric storms for equinox and winter conditions is presented based on neutral-composition measurements from the Aeros-A neutral-atmosphere temperature experiment. The main features of the two storms as inferred from changes in N2, Ar, He, and O are described, and their implications for current theories of thermospheric storms are discussed. On the basis of the study of the F-region critical frequency measured from a chain of ground-based ionospheric stations during the two storm periods, the general characteristics of the ionospheric storms and the traveling ionospheric disturbances are described. It is suggested that the positive and negative phases of ionospheric storms are different manifestations of thermospheric storms.

  19. 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.

  20. 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

  1. Technology Development for a Hyperspectral Microwave Atmospheric Sounder (HyMAS)

    NASA Technical Reports Server (NTRS)

    Blackwell, W.; Galbraith, C.; Hilliard, L.; Racette, P.; Thompson, E.

    2014-01-01

    The Hyperspectral Microwave Atmospheric Sounder (HyMAS) is being developed at Lincoln Laboratories and accommodated by the Goddard Space Flight Center for a flight opportunity on a NASA research aircraft. The term hyperspectral microwave is used to indicate an all-weather sounding instrument that performs equivalent to hyperspectral infrared sounders in clear air with vertical resolution of approximately 1 km. Deploying the HyMAS equipped scanhead with the existing Conical Scanning Microwave Imaging Radiometer (CoSMIR) shortens the path to a flight demonstration. Hyperspectral microwave is achieved through the use of independent RF antennas that sample the volume of the Earths atmosphere through various levels of frequencies, thereby producing a set of dense, spaced vertical weighting functions.

  2. Underwater Acoustic Transponders Tracking While Mapping With A Multibeam Echo-Sounder

    NASA Astrophysics Data System (ADS)

    de Moustier, C. P.; Franzheim, A.; Testa, W.; Burns, J. M.; Foy, R.

    2010-12-01

    A 160 kHz multibeam echo-sounder was used to interrogate and receive the replies from custom-built miniature underwater acoustic transponders attached to the carapace of king crabs in Womens Bay, Alaska. This new application of multibeam echo-sounders combines acoustic tracking and mapping, thus providing environmental context to the tracking information. Each transponder replies with its own coded sequence that stands out from other echoes received by the sonar. Range and bearing of the replies from multiple transponders can be obtained in a single sonar ping. The king crab experiment was done in 25-35 m of water depth, and the system was successfully tested without animals at 190 m depth. Work supported by NOAA's Undersea Research Program Grant G4768, with field work support from NOAA-NMFS/AFSC/RACE and Electronic Navigation Ltd.

  3. GeoSTAR - A Synthetic Aperture Microwave Sounder for Geostationary Missions

    NASA Technical Reports Server (NTRS)

    Lambrigtsen, Bjorn; Wilson, William; Tanner, Alan; Kangaslahti, Pekka

    2004-01-01

    The Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) is a new microwave atmospheric sounder under development. It will bring capabilities similar to those now available on low-earth orbiting environmental satellites to geostationary orbit - where such capabilities have not been available. GeoSTAR will synthesize the multimeter aperture needed to achieve the required spatial resolution, which will overcome the obstacle that has prevented a GEO microwave sounder from being implemented until now. The synthetic aperture approach has until recently not been feasible, due to the high power needed to operate the on-board high-speed massively parallel processing system required for 2D-synthesis, as well as a number of system and calibration obstacles. The development effort under way at JPL, with important contributions from the Goddard Space Flight Center and the University of Michigan, is intended to demonstrate the measurement concept and retire much of the technology risk.

  4. The Stratospheric Wind Ingrared Limb Sounder: Investigation of atmospheric dynamics and transport from Eos

    NASA Technical Reports Server (NTRS)

    Mccleese, D. J.

    1992-01-01

    The Stratospheric Wind Infrared Limb Sounder (SWIRLS) is one of the instruments in the atmospheric sounder package to be flown by NASA on the Earth Observing System (EOS) B platform in the late 1990's. SWIRLS is designed to measure the horizontal vector wind field, atmospheric temperature, and the abundances and distributions of ozone and nitrous oxide in the middle atmosphere. These measurements will constitute a dynamical climatology of the stratosphere covering time scales ranging from diurnal to interannual. In addition, the SWIRLS investigation will quantify the physical mechanisms responsible for the structure and variations of stratospheric circulation and temperature fields, including the transport of species, particularly ozone, heat and momentum. Existing data sets lack the combination of accuracy, global and temporal coverage, spatial resoultion and simultaneity required to distinguish unambiguosly between the roles of dynamical and chemical processes in determining the current distribution of ozone and its evolution in the future. The measurement objectives, measurement approach, and instrumentation of SWIRLS is described.

  5. A Model of Callisto's Ionosphere

    NASA Astrophysics Data System (ADS)

    Hartkorn, O. A.; Saur, J.; Bloecker, A.; Strobel, D. F.; Simon, S.

    2014-12-01

    We develop a model of the ionosphere of Jupiter's moon Callisto, where we assume a stationary balance between sources and sinks of electrons and electron energy. Hence, effects of electron transport and electron energy transport are neglected. At Callisto, the production of electrons and electron energy is basically driven by photoionization, which is implemented using the EUVAC model for solar activity. Dissociative recombination is the main electron loss process, whereas electron energy loss is further driven by dissociation, electron impact ionization as well as vibrational and rotational excitations of neutral atmospheric particles. All these effects are incorporated within our model by considering the associated cross sections. The neutral atmosphere is assumed to be stationary and consists of molecular oxygen with a column density of 3 to 4 x 1020 m-2 (e.g. Kliore et al. (2002), Liang et al. (2005)). Our results can be compared to radio occultation observations of four Galileo spacecraft flybys reported by Kliore et al. (2002), which shows that this simple model can explain the general pattern of the observational data. Indeed, our results indicate that the detection of enhanced electron densities is very sensitive to the exact position of the tangential point of the radio occultation method. Our model shows that photoionization produces a strong asymmetry of the electron density distribution between day and night-side of the moon. Further, model results for the electron energy allow for an estimation of the day glow of Callisto's atmosphere. This can be compared to HST observations (Strobel et al. (2002)) in order to evaluate the density of the neutral oxygen atmosphere. Future studies imply the modeling of the modification of the ionospheric structure through interaction with upstreaming jovian magnetospheric plasma.

  6. 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

  7. An Ionospheric Metric Study Using Operational Models

    NASA Astrophysics Data System (ADS)

    Sojka, J. J.; Schunk, R. W.; Thompson, D. C.; Scherliess, L.; Harris, T. J.

    2006-12-01

    One of the outstanding challenges in upgrading ionospheric operational models is quantifying their improvement. This challenge is not necessarily an absolute accuracy one, but rather answering the question, "Is the newest operational model an improvement over its predecessor under operational scenarios?" There are few documented cases where ionospheric models are compared either with each other or against "ground truth". For example a CEDAR workshop team, PRIMO, spent almost a decade carrying out a models comparison with ionosonde and incoherent scatter radar measurements from the Millstone Hill, Massachusetts location [Anderson et al.,1998]. The result of this study was that all models were different and specific conditions could be found when each was the "best" model. Similarly, a National Space Weather Metrics ionospheric challenge was held and results were presented at a National Space Weather meeting. The results were again found to be open to interpretation, and issues with the value of the specific metrics were raised (Fuller-Rowell, private communication, 2003). Hence, unlike the tropospheric weather community, who have established metrics and exercised them on new models over many decades to quantify improvement, the ionospheric community has not yet settled on a metric of both scientific and operational value. We report on a study in which metrics were used to compare various forms of the International Reference Ionosphere (IRI), the Ionospheric Forecast Model (IFM), and the Utah State University Global Assimilation of Ionospheric Measurements Model (USU-GAIM) models. The ground truth for this study was a group of 11 ionosonde data sets taken between 20 March and 19 April 2004. The metric parameter was the ionosphere's critical frequency. The metric was referenced to the IRI. Hence, the study addressed the specific question what improvement does IFM and USU-GAIM have over IRI. Both strengths (improvements) and weaknesses of these models are discussed

  8. 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.

  9. Level 1B products from the Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Aumann, H. H.; Overoye, Ken

    2003-01-01

    The Atmospheric Infrared Sounder (AIRS) was launched May 4, 2002 on the EOS Aqua Spacecraft. A discussion is given of the objectives of the AIRS experiment, including requirements on the data products. We summarize the instrument characteristics, including sensitivity, noise, and spectral response, and preflight calibration results leading to the estimate of the calibration accuracy. The Level 1B calibration algorithm is presented as well as the results of in-flight stability and sensitivity measurements.

  10. Demonstrating the Operational Value of Atmospheric Infrared Sounder (AIRS) Profiles in the Pre-Convective Environment

    NASA Technical Reports Server (NTRS)

    Kozlowski, Danielle; Zavodsky, Bradley; Stano, Geoffrey; Jedlovec, Gary

    2011-01-01

    The Short-term Prediction Research and Transition (SPoRT) is a project to transition those NASA observations and research capabilities to the weather forecasting community to improve the short-term regional forecasts. This poster reviews the work to demonstrate the value to these forecasts of profiles from the Atmospheric Infrared Sounder (AIRS) instrument on board the Aqua satellite with particular assistance in predicting thunderstorm forecasts by the profiles of the pre-convective environment.

  11. Solar Cycle Variations in the Polar Ionosphere

    NASA Astrophysics Data System (ADS)

    Burrell, A. G.; Yeoman, T. K.; Milan, S. E.; Lester, M.

    2014-12-01

    The polar ionosphere is a dynamic region that readily responds to changes in solar irradiance, solar wind, the magnetosphere, and the neutral atmosphere. The most recent solar minimum brought to light gaps in the current understanding of the relationship between ionospheric structure and solar irradiance. The Super Dual Auroral Radar Network (SuperDARN) offers an invaluable dataset for studying long-term ionospheric variability, as it has been continuously providing extensive coverage of the northern and southern polar ionosphere since 1995 (the solar minimum preceding the 23rd solar cycle). An under-utilized portion of the SuperDARN dataset is the ground-backscatter: the backscatter that returns from a reflection point on the ground along an open (or irregularity-free) propagation path. The ground-backscatter provides a measure the ionospheric density at the peak of the radar signal's path. These measurements are used to the examine the changes in the bottomside, polar ionosphere over the 23rd and 24th solar cycles.

  12. 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.

  13. LIFDAR: A Diagnostic Tool for the Ionosphere

    NASA Astrophysics Data System (ADS)

    Kia, O. E.; Rodgers, C. T.; Batholomew, J. L.

    2011-12-01

    ITT Corporation proposes a novel system to measure and monitor the ion species within the Earth's ionosphere called Laser Induced Fluorescence Detection and Ranging (LIFDAR). Unlike current ionosphere measurements that detect electrons and magnetic field, LIFDAR remotely measures the major contributing ion species to the electron plasma. The LIFDAR dataset has the added capability to demonstrate stratification and classification of the layers of the ionosphere to ultimately give a true tomographic view. We propose a proof of concept study using existing atmospheric LIDAR sensors combined with a mountaintop observatory for a single ion species that is prevalent in all layers of the atmosphere. We envision the LIFDAR concept will enable verification, validation, and exploration of the physics of the magneto-hydrodynamic models used in ionosphere forecasting community. The LIFDAR dataset will provide the necessary ion and electron density data for the system wide data gap. To begin a proof of concept, we present the science justification of the LIFDAR system based on the model photon budget. This analysis is based on the fluorescence of ionized oxygen within the ionosphere versus altitude. We use existing model abundance data of the ionosphere during normal and perturbed states. We propagate the photon uncertainties from the laser source through the atmosphere to the plasma and back to the collecting optics and detector. We calculate the expected photon budget to determine signal to noise estimates based on the targeted altitude and detection efficiency. Finally, we use these results to derive a LIFDAR observation strategy compatible with operational parameters.

  14. Ultraspectral sounder data compression using error-detecting reversible variable-length coding

    NASA Astrophysics Data System (ADS)

    Huang, Bormin; Ahuja, Alok; Huang, Hung-Lung; Schmit, Timothy J.; Heymann, Roger W.

    2005-08-01

    Nonreversible variable-length codes (e.g. Huffman coding, Golomb-Rice coding, and arithmetic coding) have been used in source coding to achieve efficient compression. However, a single bit error during noisy transmission can cause many codewords to be misinterpreted by the decoder. In recent years, increasing attention has been given to the design of reversible variable-length codes (RVLCs) for better data transmission in error-prone environments. RVLCs allow instantaneous decoding in both directions, which affords better detection of bit errors due to synchronization losses over a noisy channel. RVLCs have been adopted in emerging video coding standards--H.263+ and MPEG-4--to enhance their error-resilience capabilities. Given the large volume of three-dimensional data that will be generated by future space-borne ultraspectral sounders (e.g. IASI, CrIS, and HES), the use of error-robust data compression techniques will be beneficial to satellite data transmission. In this paper, we investigate a reversible variable-length code for ultraspectral sounder data compression, and present its numerical experiments on error propagation for the ultraspectral sounder data. The results show that the RVLC performs significantly better error containment than JPEG2000 Part 2.

  15. Inter-Comparison of GOES-8 Imager and Sounder Skin Temperature Retrievals

    NASA Technical Reports Server (NTRS)

    Haines, Stephanie L.; Suggs, Ronnie J.; Jedlovec, Gary J.; Arnold, James E. (Technical Monitor)

    2001-01-01

    Skin temperature (ST) retrievals derived from geostationary satellite observations have both high temporal and spatial resolutions and are therefore useful for applications such as assimilation into mesoscale forecast models, nowcasting, and diagnostic studies. Our retrieval method uses a Physical Split Window technique requiring at least two channels within the longwave infrared window. On current GOES satellites, including GOES-11, there are two Imager channels within the required spectral interval. However, beginning with the GOES-M satellite the 12-um channel will be removed, leaving only one longwave channel. The Sounder instrument will continue to have three channels within the longwave window, and therefore ST retrievals will be derived from Sounder measurements. This research compares retrievals from the two instruments and evaluates the effects of the spatial resolution and sensor calibration differences on the retrievals. Both Imager and Sounder retrievals are compared to ground-truth data to evaluate the overall accuracy of the technique. An analysis of GOES-8 and GOES-11 intercomparisons is also presented.

  16. Wide Field Collimator 2 (WFC2) for GOES Imager and Sounder

    NASA Technical Reports Server (NTRS)

    Etemad, Shahriar; Bremer, James C.; Zukowski, Barbara J.; Pasquale, Bert A.; zukowski, Tmitri J.; Prince, Robert E.; O'Neill, Patrick A.; Ross, Robert W.

    2004-01-01

    Two of the GOES instruments, the Imager and the Sounder, perform scans of the Earth to provide a full disc picture of the Earth. To verify the entire scan process, an image of a target that covers an 18 deg. circular field-of-view is collimated and projected into the field of regard of each instrument. The Wide Field Collimator 2 (WFC2) has many advantages over its predecessor, WFC1, including lower thermal dissipation higher fir field MTF, smaller package, and a more intuitive (faster) focusing process. The illumination source is an LED array that emits in a narrow spectral band centered at 689 nm, within the visible spectral bands of the Imager and Sounder. The illumination level can be continuously adjusted electronically. Lower thermal dissipation eliminates the need for forced convection cooling and minimizes time to reach thermal stability. The lens system has been optimized for the illumination source spectral output and athernalized to remain in focus during bulk temperature changes within the laboratory environment. The MTF of the lens is higher than that of the WFC1 at the edge of FOV. The target is focused in three orthogonal motions, controlled by an ergonomic system that saves substantial time and produces a sharper focus. Key words: Collimator, GOES, Imager, Sounder, Projector

  17. A new multibeam echo sounder/sonar for fishery research applications

    NASA Astrophysics Data System (ADS)

    Andersen, Lars Nonboe; Berg, Sverre; Stenersen, Erik; Gammelsaeter, Ole Bernt; Lunde, Even Borte

    2003-10-01

    Fisheries scientists have for many years been requesting a calibrated multibeam echo sounder/sonar specially designed for fishery research applications. Simrad AS has, in cooperation with IFREMER, France, agreed on specifications for a multibeam echo sounder and with IMR, Norway for a multibeam sonar, and contracts were signed for development of such systems in January 2003. The systems have 800 transmitting and receiving channels with similar hardware, but different software, and are characterized by narrow beams, low-sidelobe levels, and operate in the frequency range 70-120 kHz. The echo sounder is designed for high operating flexibility, with 1 to 47 beams of approximately 2°, covering a maximum sector of 60°. In addition, normal split beam mode on 70 and 120 kHz with 7° beams for comparison with standard system is available. The sonar will be mounted on a drop keel, looking horizontally, covering a horizontal sector of +/-30°, and a vertical sector of 45°. Total number of beams is 500, 25 beams horizontally with a resolution of ~3°, and 20 beams vertically with a resolution of ~4°. Both systems are designed for accurate fish-stock assessment and fish-behavior studies.

  18. Calibration status of the Atmospheric Infrared Sounder after eleven years in operation

    NASA Astrophysics Data System (ADS)

    Elliott, Denis A.; Weiler, Margie; Manning, Evan M.; Pagano, Thomas S.; Broberg, Steven E.; Aumann, Hartmut H.

    2013-09-01

    The Atmospheric Infrared Sounder (AIRS) is a grating array infrared hyperspectral sounder with 2378 channels from 3.75 to 15.4 microns with spectral resolution 1200 to 1400 depending on the channel. AIRS was designed as an aid to weather prediction and for atmospheric process studies. It produces profiles of atmospheric temperature and water vapor. Because of its spectral coverage and spectral resolution it is sensitive to a number of trace atmospheric constituents including CO2, CO, SO2, O3, and CH4. The AIRS sensitivity, stability, and long life have led to its use in climate process studies and climate model validation, both of which place far more stringent requirements on calibration than weather forecasting does. This paper describes results from several special calibration sequences, originally developed for prelaunch testing, that have been used to monitor the AIRS calibration accuracy and instrument health on-orbit, including the scan mirror, space view response, and channel health. It also describes reanalyses of pre-launch calibration data used to determine calibration parameters. Finally, it shows comparisons of AIRS radiometry with two other hyperspectral infrared sounders presently in space—IASI and CrIS.

  19. Atmospheric River Observations with the HAMSR Aircraft Microwave Sounder

    NASA Astrophysics Data System (ADS)

    Lambrigtsen, B.; Brown, S. T.; Schreier, M. M.; Dang, H. V. T.; Behrangi, A.

    2015-12-01

    The High Altitude MMIC Sounding Radiometer (HAMSR) was developed at the Jet Propulsion Laboratory in 2001 to serve as an aircraft based hurricane observatory. It initially flew on the high altitude ER-2 and later on the DC-8. More recently it was modified to fly on the Global Hawk UAV. It uses the most advanced technology and is among the most sensitive instruments of its kind. In addition to a number of NASA hurricane field campaigns - mostly in the North Atlantic, HAMSR has participated in two atmospheric river campaigns off the California coast, one in 2011 (WISPAR) and one in 2015 (CalWater2). We will discuss observations from the 2015 campaign, with particular focus on a flight over an atmsospheric river making landfall in central California in early February, as well as compare with highlights from the 2011 flights. Copyright 2015 California Institute of Technology. Government sponsorship acknowledged.

  20. Comparison of the USU ionospheric model with the UCL-Sheffield coupled thermospheric-ionospheric model

    NASA Technical Reports Server (NTRS)

    Sojka, J. J.; Schunk, R. W.; Rees, D.; Fuller-Rowell, T. J.; Moffett, R. J.; Quegan, S.

    1992-01-01

    Several physical models of the high-latitude ionosphere have been developed that describe the time-dependent evolution of the E- and F-region plasma density. The models require a variety of inputs, including solar EUV fluxes, magnetospheric convection, auroral precipitation, and neutral atmosphere. Of specific relevance to this study is how the neutral atmosphere is incorporated into the ionospheric models. For the USU ionospheric model, the neutral atmosphere is the MSIS 1986 empirical model, while for the UCL-Sheffield coupled thermospheric-ionospheric model the neutral atmosphere is computed simultaneously with the ionosphere. Both models were run for similar solar and magnetospheric conditions (solar maximum, moderate geomagnetic activity, and winter solstice). Solar maximum conditions ensured a strong coupling between the ionosphere and thermosphere, which provided the possibility of a large ionospheric difference between the two physical models. This was further enhanced by choosing winter conditions so that the densities were not dominated by sunlight. The comparison of the two models indicated that both models predict the same morphological features with similar ionospheric densities, generally within about 30 percent.

  1. Solar cycle variations in the ionosphere of Mars as seen by multiple Mars Express data sets

    NASA Astrophysics Data System (ADS)

    Sánchez-Cano, B.; Lester, M.; Witasse, O.; Milan, S. E.; Hall, B. E. S.; Cartacci, M.; Peter, K.; Morgan, D. D.; Blelly, P.-L.; Radicella, S.; Cicchetti, A.; Noschese, R.; Orosei, R.; Pätzold, M.

    2016-03-01

    The response of the Martian ionosphere to solar activity is analyzed by taking into account variations in a range of parameters during four phases of the solar cycle throughout 2005-2012. Multiple Mars Express data sets have been used (such as Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) in Active Ionospheric Sounding, MARSIS subsurface, and MaRS Radio Science), which currently cover more than 10 years of solar activity. The topside of the main ionospheric layer behavior is empirically modeled through the neutral scale height parameter, which describes the density distribution in altitude, and can be used as a dynamic monitor of the solar wind-Martian plasma interaction, as well as of the medium's temperature. The main peak, the total electron content, and the relationship between the solar wind dynamic pressure and the maximum thermal pressure of the ionosphere with the solar cycle are assessed. We conclude that the neutral scale height was different in each phase of the solar cycle, having a large variation with solar zenith angle during the moderate-ascending and high phases, while there is almost no variation during the moderate-descending and low phases. Between end-2007 and end-2009, an almost permanent absence of secondary layer resulted because of the low level of solar X-rays. Also, the ionosphere was more likely to be found in a more continuously magnetized state. The induced magnetic field from the solar wind, even if weak, could be strong enough to penetrate more than at other solar cycle phases.

  2. Electric Field Double Probe Measurements for Ionospheric Space Plasma Experiments

    NASA Technical Reports Server (NTRS)

    Pfaff, R.

    1999-01-01

    Double probes represent a well-proven technique for gathering high quality DC and AC electric field measurements in a variety of space plasma regimes including the magnetosphere, ionosphere, and mesosphere. Such experiments have been successfully flown on a variety of spacecraft including sounding rockets and satellites. Typical instrument designs involve a series of trades, depending on the science objectives, type of platform (e.g., spinning or 3-axis stabilized), expected plasma regime where the measurements will be made, available telemetry, budget, etc. In general, ionospheric DC electric field instruments that achieve accuracies of 0.1 mV/m or better, place spherical sensors at large distances (10m or more) from the spacecraft body in order to extend well beyond the spacecraft wake and sheath and to achieve large signal-to-noise ratios for DC and long wavelength measurements. Additional sets of sensors inboard of the primary, outermost sensors provide useful additional information, both for diagnostics of the plasma contact potentials, which particularly enhance the DC electric field measurements on non-spinning spacecraft, and for wavelength and phase velocity measurements that use the spaced receiver or "interferometer" technique. Accurate attitude knowledge enables B times V contributions to be subtracted from the measured potentials, and permits the measured components to be rotated into meaningful geophysical reference frames. We review the measurement technique for both DC and wave electric field measurements in the ionosphere discussing recent advances involving high resolution burst memories, multiple baseline double probes, new sensor surface materials, biasing techniques, and other considerations.

  3. 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

  4. Heat balance of the ionosphere - Implications for the International Reference Ionosphere

    NASA Technical Reports Server (NTRS)

    Bilitza, D.

    1985-01-01

    Theoretical considerations can be helpful tools in modeling ionospheric parameters in regions and for times where not enough experimental data are available. This study asks whether results of heat balance calculations should be introduced to supplement the data base for the International Reference Ionosphere. The present status of the theoretical understanding is discussed and the influence of the following unresolved or neglected times are examined: (1) electron heating rate, (2) electron cooling by fine structure excitation of atomic oxygen, and (3) height-dependent Coulomb Logarithm. The ambiguity introduced by these terms leads to up to 30 percent uncertainty in the electron temperature of the lower ionosphere. The electron temperature in the upper ionosphere is largely determined by heat conduction from above and depends critically on the conditions assumed at the boundary between ionosphere and plasmasphere.

  5. Statistical Characteristics of MF/HF Auroral Radio Emissions Emanating from the Topside Ionosphere

    NASA Astrophysics Data System (ADS)

    Sato, Y.; Kumamoto, A.; Katoh, Y.; Shinbori, A.

    2014-12-01

    The terrestrial auroral ionosphere is a natural emitter of electromagnetic waves in the MF/HF ranges (up to 6 MHz) as well as well-known intense auroral kilometric radiation (AKR) and auroral hiss in the VLF/LF ranges. We report on the statistical properties of Terrestrial Hectometric Radiation (THR), MF/HF auroral radio emissions emanating from the topside ionosphere, using a long-term data set obtained from the Plasma Waves and Sounder (PWS) experiment mounted on the Akebono satellite during 2 solar cycles. THR typically occurs in either or both of two frequency bands near 1.5-2.0 MHz and 3.0-4.0 MHz, whose polarization features correspond to the L-O and R-X mode. Statistical studies using the Akebono/PWS data reveal clear bimodality in the frequency distribution of THR with two broad peaks near 1.6 MHz and 3.6 MHz and the spatial distribution of occurrence rate of THR-L (lower than 2.5 MHz) and THR-H (higher than 2.5 MHz). In the morning to postnoon sectors (3h-15h MLT), the spatial distribution of both types of THR is confined to magnetic latitudes higher than 70 deg, while during nighttime (15h-3h MLT) it spreads to lower magnetic latitudes (~ 30 deg) at higher altitudes. The explanation of this distribution is that THR is generated in the night-side auroral latitudes near 1000-km altitude and propagation effect makes an emission cone. Occurrence rate of THR-L is higher than that of THR-H. The long-term Akebono/PWS data also show clear solar activity dependence and seasonal variations of THR appearance; THR occurrence rate drops from a few percent during solar maxima to 0.1 percent or less during solar minima and is the highest in summer and the lowest in winter.

  6. Ionospheric irregularity influences on GPS time delay

    NASA Astrophysics Data System (ADS)

    Mansoori, Azad Ahmad; Gwal, Ashok Kumar; Khan, Parvaiz A.; Bhawre, Purushottam

    All the trans-ionospheric signals interact with the ionosphere during their passage through ionosphere, hence are strongly influenced by the ionosphere. One of most important ionospheric effects on the trans-ionospheric signals is the delay both in range and time. Under this investigation we have studied the variability of ionospheric range delay in GPS signals. To accomplish this study we have used the GPS measurements at a low latitude station, IISC Bangalore (13.02N, 77.57E) during January 2012 to December 2012. We studied the diurnal monthly as well as seasonal variability of the range delay. We also selected five intense geomagnetic storms that occurred during 2012 and investigated the variability of delay during the disturbed conditions. From our study we found the diurnal variability of the range delay is similar to the diurnal pattern observed for TEC. The delay is maximum during the month of October while lowest delay is found to occur in the month of December. During summer season the range delay in GPS signals in less while the largest delay occurs during the equinox season. The variability of delay during the geomagnetic storms of 09 Mar. 2012, 24 Apr. 2012, 15 Jul. 2012, 01 Oct. 2012 and 14 Nov. 2012 were also studied. All these geomagnetic storms belonged to intense category. We found that the value of delay is strongly increased during the course of geomagnetic storms. We took the peak value of delay as well as calculated the enhancement in the delay during these geomagnetic storms and then investigated their correlation with the storm intensity index Dst. Both the delays follow a very good correlation with Dst index.

  7. 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.

  8. 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.

  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. The global ionosphere thermosphere model

    NASA Astrophysics Data System (ADS)

    Ridley, A. J.; Deng, Y.; Tóth, G.

    2006-05-01

    The recently created global ionosphere thermosphere model (GITM) is presented. GITM uses a three-dimensional spherical grid that can be stretched in both latitude and altitude, while having a fixed resolution in longitude. GITM is nontraditional in that it does not use a pressure-based coordinate system. Instead it uses an altitude-based grid and does not assume a hydrostatic solution. This allows the model to more realistically capture physics in the high-latitude region, where auroral heating is prevalent. The code can be run in a one-dimensional (1-D) or three-dimensional (3-D) mode. In 3-D mode, the modeling region is broken into blocks of equal size for parallelization. In 1-D mode, a single latitude and longitude is modeled by neglecting any horizontal transport or gradients, except in the ionospheric potential. GITM includes a modern advection solver and realistic source terms for the continuity, momentum, and energy equations. Each neutral species has a separate vertical velocity, with coupling of the velocities through a frictional term. The ion momentum equation is solved for assuming steady-state, taking into account the pressure, gravity, neutral winds, and external electric fields. GITM is an extremely flexible code—allowing different models of high-latitude electric fields, auroral particle precipitation, solar EUV inputs, and particle energy deposition to be used. The magnetic field can be represented by an ideal dipole magnetic field or a realistic APEX magnetic field. Many of the source terms can be controlled (switched on and off, or values set) by an easily readable input file. The initial state can be set in three different ways: (1) using an ideal atmosphere, where the user inputs the densities and temperature at the bottom of the atmosphere; (2) using MSIS and IRI; and (3) restarting from a previous run. A 3-D equinox run and a 3-D northern summer solstice run are presented. These simulations are compared with MSIS and IRI to show that the

  11. Mars ionosphere total electron content analysis from MARSIS subsurface data

    NASA Astrophysics Data System (ADS)

    Cartacci, M.; Amata, E.; Cicchetti, A.; Noschese, R.; Giuppi, S.; Langlais, B.; Frigeri, A.; Orosei, R.; Picardi, G.

    2013-03-01

    We describe a method to estimate the total electron content (TEC) of the Mars ionosphere from the output parameters of an algorithm, called the Contrast Method (Picardi, G., Sorge, S. [2000]. Proc. SPIE. Eighth International Conference on Ground Penetrating Radar, vol. 4084, pp. 624-629; Ilyushin, Ya.A., Kunitsyn, V.E. [2004]. J. Commun. Technol. Electron. 49, 154-165), which allows to correct the phase distortion of the echoes recorded by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) (Picardi, G. et al. [2005]. Science 310, 1925-1928) in its subsurface mode. Based on the TEC values evaluated during 6 years of MARSIS activity, corresponding to about 4600 orbits, in this paper we present a global map of the night side TEC variations, which correlates well with the magnetic field model derived from Mars Global Surveyor (MGS) Magnetometer/Electron Reflectometer (MAG/ER) data. In particular, we demonstrate that regions of enhanced TEC preferentially correspond to areas where crustal magnetic field lines are quasi perpendicular to the martian surface; moreover, we demonstrate that, in regions where the magnetic field is predominantly nearly vertical, enhanced TEC values correlate with higher field intensities, while in regions where the magnetic field is predominantly nearly horizontal, such correlation is not observed. As already suggested in the past by other authors, we suggest that increased TEC values may be related to the precipitation of electrons from the martian magnetospheric tail along vertical crustal magnetic field lines.

  12. Modeling the global positioning system signal propagation through the ionosphere

    NASA Technical Reports Server (NTRS)

    Bassiri, S.; Hajj, G. A.

    1992-01-01

    Based on realistic modeling of the electron density of the ionosphere and using a dipole moment approximation for the Earth's magnetic field, one is able to estimate the effect of the ionosphere on the Global Positioning System (GPS) signal for a ground user. The lowest order effect, which is on the order of 0.1-100 m of group delay, is subtracted out by forming a linear combination of the dual frequencies of the GPS signal. One is left with second- and third-order effects that are estimated typically to be approximately 0-2 cm and approximately 0-2 mm at zenith, respectively, depending on the geographical location, the time of day, the time of year, the solar cycle, and the relative geometry of the magnetic field and the line of sight. Given the total electron content along a line of sight, the authors derive an approximation to the second-order term which is accurate to approximately 90 percent within the magnetic dipole moment model; this approximation can be used to reduce the second-order term to the millimeter level, thus potentially improving precise positioning in space and on the ground. The induced group delay, or phase advance, due to second- and third-order effects is examined for two ground receivers located at equatorial and mid-latitude regions tracking several GPS satellites.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. The combined study of the middle atmosphere meteorological parameters and lower ionosphere dynamics over Europe by means of remote VLF-LF measurements

    NASA Astrophysics Data System (ADS)

    Zetzer, J. I.; Lyakhov, A.; Yakymenko, K.

    2012-12-01

    The results of comprehensive analysis of long-term records of VLF-LF European transmitters by means of Mikhnevo geophysical observatory (Institute of Geospheres Dynamics), SID station A118 (France) and a number of AWESOM receivers are presented. In the previous study (A.A.Egoshin et al., Izvestiya, Physics of the Solid Earth, 2012, Vol. 48, No. 3, pp. 275-286) the results obtained under the minimum solar activity were presented that have shown the link between the lower ionosphere parameters and meteorological fields of the middle atmosphere. The current study expands the evidence to the increased solar activity level as well as the number of receivers, thus allowing more dense coverage of the Europe by the radio paths. Middle atmosphere data under study were provided by the EOS Aura Microwave Limb Sounder. These asynoptic data, in turn, were processed by the space-time spectral analysis on various pressure levels for various window lengths. The results are presented for the spatial structure of wave-like perturbations in the VLF-LF signal strength, which result from the lower ionosphere disturbances on various radio paths. Special short-windowed space-time study was evaluated for the periods of anomalous temporal behavior of the VLF-LF signals and the results of the altitude-latitude mode structures of the geopotential height, neutral temperature, water and ozone constituents are presented. It is shown that the spatial properties of the lower ionosphere can vary significantly at relatively small scale. Moreover, the altitude-latitude mode structures do not coincide in space as well as in time, thus, complicating the lower ionosphere response to the meteorological variations of the middle atmosphere. The analysis of all assembled data proves two main points. At first, it is possible to evaluate synoptic long-term monitoring of the middle atmosphere via the lower ionosphere perturbations as seen by VLF-LF receivers. At second, the theoretical models of the lower

  19. 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.

  20. Fast ionospheric feedback instability and substorm onset

    NASA Technical Reports Server (NTRS)

    Lysak, Robert L.; Grieger, John; Song, Yan

    1992-01-01

    A study suggesting that the Alfven resonator can play an important role in modifying the ionosphere on the time and space scales required to play a significant role in substorm formation is presented. Although the effect of magnetosphere-ionosphere coupling on the onset of substorms has been studied, the effects due to gradients of the Alfven speed along auroral field line were neglected. The large increase of the Alfven speed with altitude above the ionosphere creates an effective resonant cavity, which can lead to fluctuations in the electric and magnetic fields as well as in particle fluxes in the range 0.1 to 1 Hz. Such fluctuations can be observed from the ground as PiB pulsations associated with substorm onset. These fluctuations can be excited by a fast feedback instability, which can grow on time scales much less than the Alfven travel time between the ionosphere and the plasma sheet. The instability enhances the value of both the Pedersen and Hall conductivity, and may play a role in preparing the ionosphere for substorm onset.

  1. Comparison of global and regional ionospheric models

    NASA Astrophysics Data System (ADS)

    Ranner, H.-P.; Krauss, S.; Stangl, G.

    2012-04-01

    Modelling of the Earth's ionosphere means the description of the variability of the vertical TEC (Total Electron Content) in dependence of geographic latitude and longitude, height, diurnal and seasonal variation as well as solar activity. Within the project GIOMO (next Generation near real-time IOnospheric MOdels) the objectives are the identification and consolidation of improved ionospheric modelling technologies. The global models Klobuchar (GPS) and NeQuick (currently in use by EGNOS, in future used by Galileo) are compared to the IGS (International GNSS Service) Final GIM (Global Ionospheric Map). Additionally a RIM (Regional Ionospheric Map) for Europe provided by CODE (Center for Orbit Determination in Europe) is investigated. Furthermore the OLG (Observatorium Lustbühel Graz) regional models are calculated for two test beds with different latitudes and extensions (Western Austria and the Aegean region). There are three different approaches, two RIMs are based on spherical harmonics calculated either from code or phase measurements and one RIM is based on a Taylor series expansion around a central point estimated from zero-difference observations. The benefits of regional models are the local flexibility using a dense network of GNSS stations. Near real-time parameters are provided within ten minutes after every clock hour. All models have been compared according to their general behavior, the ability to react upon extreme solar events and the robustness of estimation. A ranking of the different models showed a preference for the RIMs while the global models should be used within a fall-back strategy.

  2. Characteristics of High Latitude Ionosphere Scintillations

    NASA Astrophysics Data System (ADS)

    Morton, Y.

    2012-12-01

    As we enter a new solar maximum period, global navigation satellite systems (GNSS) receivers, especially the ones operating in high latitude and equatorial regions, are facing an increasing threat from ionosphere scintillations. The increased solar activities, however, also offer a great opportunity to collect scintillation data to characterize scintillation signal parameters and ionosphere irregularities. While there are numerous GPS receivers deployed around the globe to monitor ionosphere scintillations, most of them are commercial receivers whose signal processing mechanisms are not designed to operate under ionosphere scintillation. As a result, they may distort scintillation signal parameters or lose lock of satellite signals under strong scintillations. Since 2008, we have established and continuously improved a unique GNSS receiver array at HAARP, Alaska. The array contains high ends commercial receivers and custom RF front ends which can be automatically triggered to collect high quality GPS and GLONASS satellite signals during controlled heating experiments and natural scintillation events. Custom designed receiver signal tracking algorithms aim to preserve true scintillation signatures are used to process the raw RF samples. Signal strength, carrier phase, and relative TEC measurements generated by the receiver array since its inception have been analyzed to characterize high latitude scintillation phenomena. Daily, seasonal, and solar events dependency of scintillation occurrence, spectral contents of scintillation activities, and plasma drifts derived from these measurements will be presented. These interesting results demonstrate the feasibility and effectiveness of our experimental data collection system in providing insightful details of ionosphere responses to active perturbations and natural disturbances.

  3. Ionospheric TEC observations from TOPEX satellite

    SciTech Connect

    Vladimer, J.A.; Ewell, V.R.; Lee, M.C.; Doherty, P.H.; Decker, D.T.; Anderson, D.N.; Klobuchar, J.A.

    1996-12-31

    Variability of Total Electron Content (TEC) in the equatorial anomaly region of the ionosphere can be studied extensively using the results of measurements taken by the NASA/CNES satellite, TOPEX/Poseidon. The NASA radar altimeter (NRA) is the first space-borne dual-frequency altimeter capable of accurately measuring vertical ionospheric TEC below 1,340 km. TOPEX TEC observations have already been used to support results from an ionospheric measurement campaign that was conducted in equatorial anomaly regions of South America by Phillips Laboratory in Spring, 1994. The best agreement in TEC values is seen during intervals of longitudinal proximity of the satellites` paths. The TOPEX over-ocean data can be used as a supplement to land based measurements in applications to ionospheric research at low and middle latitudes. This study focuses on comparisons between TOPEX vertical TEC data and GPS equivalent vertical TEC measurements taken near the East and West coastal regions of South America. Also the Phillips Laboratory Global Parameterized Ionospheric Model (PIM) is utilized in an effort to estimate slant to vertical conversion errors.

  4. 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.

  5. Geophysicochemical model of an ionospheric auroral gyroscope

    NASA Astrophysics Data System (ADS)

    Serban, Andreea I.; Geicu, Ovidiu I.; Serban, Florea

    2016-01-01

    This study presents a geophysicochemical model of an ionospheric auroral gyroscope. The gyroscopic effect occurs due to the electromagnetic interaction in Earth's polar regions between two types of vertical cavity auroras: the herpolhodic cone (proton cavity aurora), operating in the cusp polar region, and two polhodic cones (an electronic cone and a protonic cone), operating in the aurora region. The ratio between the angular speeds of the herpolhodic and polhodic cones is established by the angle between Earth's rotational axis and the geomagnetic dipole axis. We have developed a theory of the ionospheric auroral gyroscope as a kinematic part of the terrestrial magnetosphere and ionosphere that enables a unified explanation of important macroscopic phenomena that occur at this level. Accordingly, we have explained the oval shape of the polar auroras, Schumann resonances, geomagnetic micropulsation excitation, and the structuring of Earth's areas of radiation. The terrestrial gravitomagnetic field and dark matter are implicated in the initiation and behavior of the auroral ionospheric gyroscope, both of which provide stability and accuracy. Viewed in a wider context, the ionospheric auroral gyroscope theory could offer a way to experimentally investigate dark matter on Earth. Furthermore, it may have a potential value as a predictive tool, providing information about the large earthquakes and Earth's phenomena.

  6. Empirical model of topside polar ionosphere

    NASA Astrophysics Data System (ADS)

    Watanabe, S.; Abe, T.; Sagawa, E.; Yau, A. W.

    A new model of topside polar ionosphere was made on the bases of data obtained by Suprathermal Ion Mass Spectrometer (SMS) installed in Akebono satellite. The SMS measures ion energy distributions in the energy range from 0 to 25 eV and in the mass range from 1 to 64 m/q. The satellite still continues to observe the topside polar ionosphere in the periods more than one solar cycle from 1989. Model functions in the 5 dimensional space were fitted to the data, such as plasma parameters of density, velocity and temperature, with a least square method. The model of topside polar ionosphere provides ion densities, ion velocities and ion temperatures of H+, He+ and O+ as functions of magnetic latitude, magnetic local time, altitude, F10.7 solar flux intensity and geomagnetic activity. The model results show clearly the solar activity dependence of ion density and that of ion escape flux from topside polar ionosphere to the magnetosphere. Both the density and the escape flux increase during the solar maximum. The flux from topside polar ionospheres exceeds more than 10 tons/day. We suggest that the ion escape is one of the source mechanisms of magnetospheric plasma and affects the evolution of the earth's atmosphere.

  7. An Antarctica-to-Spain HF ionospheric radio link: Sounding results

    NASA Astrophysics Data System (ADS)

    Vilella, C.; Miralles, D.; Pijoan, J. L.

    2008-08-01

    Our research group in Electromagnetism and Communications is involved in a project dealing with the channel characterization of an ionospheric radio link from the Spanish Antarctic Base (62.6°S, 60.4°W) to the Observatori de l'Ebre (40.8°N, 0.5°E) in Spain. Since the link was established for the first time on December 2003, the sounder and measurement techniques have been improved on the basis of the preliminary results. In this paper, the final results of the project corresponding to the 2006/2007 sounding survey are presented. First the hardware and measurement techniques used to probe the channel are described. Then the results in terms of channel availability (and its daily, hourly, and frequency variation), multipath and Doppler spreads, and signal-to-noise ratio are discussed. These results are being used to design the physical layer of a low data rate transmission system intended to send the information acquired by a geomagnetic sensor in the Antarctica.

  8. Bistatic phase sounding in the ionosphere above the Minor Scale explosion

    NASA Astrophysics Data System (ADS)

    Fitzgerald, J.

    1986-02-01

    A 4.8-kT chemical explosion named Minor Scale was detonated at the White Sands Missile Range on June 26, 1985. Following the detonation, three bistatic HF phase sounders observed disturbances in the ionosphere directly over the explosion. The path from transmitters to receivers, which were 283 km apart, had a midpoint 7 km northeast of ground zero. We describe the experiment and present time histories of the power spectra of the three transmission. Between 300 and 360 s after the explosion, all three links showed changes in spectra. The lowest frequency shifted by -1 Hz, indicating the passage of the acoustic wave from the explosion through the total reflection height in the E-layer at about 95 km. We model the Doppler shift and absorption change to be expected for this disturbance assuming the acoustic wave had an N-wave profile with a maximum amplitude of 15%. The spectra of the lowest frequency also show temporary peaks at negative Doppler that indicate partial reflection modes from upper and lower edges of the N-wave. We calculate the Doppler shift and reflection coefficients for these partial reflection modes. During the same time period, the spectra of the two higher frequency transmissions also showed temporary peaks at negative Doppler that rapidly changed their frequency offset.

  9. The morphology and physical interpretations of the longitudinal variations in the ionospheric plasma density at low-, mid- and high-latitudes

    NASA Astrophysics Data System (ADS)

    Klimenko, Maxim; Klimenko, Vladimir; Cherniak, Iurii; Zakharenkova, Irina; Ratovsky, Konstantin; Karpachev, Alexander

    As it is well known the longitudinal variations in the ionospheric electron density at equatorial, low-, mid- and high-latitudes have a number of similarities and differences. The data obtained from topside ionospheric sounding, GPS-LEO radio occultation method, worldwide network of ground-based ionosondes and GPS receivers were previously used for investigations of the various kinds of manifestations of the longitudinal ionospheric variability. We discuss and present the brief review of the recent advances and outstanding problems in this important scientific issue. We paid a special attention into our understanding of local time, seasonal, geomagnetic and solar activity dependence of the longitudinal variations in the ionospheric F region parameters. Another main objective of our report is to describe the theoretical understanding and recent model finding of the main formation mechanisms of ionospheric longitudinal variations using the Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP). We compared the GSM TIP model results with IRI empirical model, and different observation data (Intercosmos-19 satellite, DPS-4 ionosondes, GPS TEC and COSMIC ionospheric electron content). This work was supported by RFBR Grants №14-05-00788, №14-05-00578, and Program 22 RAS.

  10. A Comparative Study of the Ionospheric TEC Measurements Using Global Ionospheric Maps of GPS, TOPEX Radar and the Bent Model

    NASA Technical Reports Server (NTRS)

    Ho, C.; Wilson, B.; Mannucci, A.; Lindqwister, U.; Yuan, D.

    1997-01-01

    Global ionospheric mapping (GIM) is a new, emerging technique for determining global ionospheric TEC (total electron content) based on measurements from a worldwide network of Global Positioning System (GPS) receivers.

  11. Ionospheric and plasmaspheric electron contents inferred from radio occultations and global ionospheric maps

    NASA Astrophysics Data System (ADS)

    González-Casado, G.; Juan, J. M.; Sanz, J.; Rovira-Garcia, A.; Aragon-Angel, A.

    2015-07-01

    We introduce a methodology to extract the separate contributions of the ionosphere and the plasmasphere to the vertical total electron content, without relying on a fixed altitude to perform that separation. The method combines two previously developed and tested techniques, namely, the retrieval of electron density profiles from radio occultations using an improved Abel inversion technique and a two-component model for the topside ionosphere plus protonosphere. Taking measurements of the total electron content from global ionospheric maps and radio occultations from the Constellation Observing System for Meteorology, Ionosphere, and Climate/FORMOSAT-3 constellation, the ionospheric and plasmaspheric electron contents are calculated for a sample of observations covering 2007, a period of low solar and geomagnetic activity. The results obtained are shown to be consistent with previous studies for the last solar minimum period and with model calculations, confirming the reversal of the winter anomaly, the hemispheric asymmetry of the semiannual anomaly, and the existence in the plasmasphere of an annual anomaly in the South American sector of longitudes. The analysis of the respective fractional contributions from the ionosphere and the plasmasphere to the total electron content shows quantitatively that during the night the plasmasphere makes the largest contribution, peaking just before sunrise and during winter. On the other hand, the fractional contribution from the ionosphere reaches a maximum value around noon, which is nearly independent of season and geomagnetic latitude.

  12. Global scale, physical models of the F region ionosphere

    NASA Technical Reports Server (NTRS)

    Sojka, J. J.

    1989-01-01

    Consideration is given to the development and verification of global computer models of the F-region which simulate the interactions between physical processes in the ionosphere. The limitations of the physical models are discussed, focusing on the inputs to the ionospheric system such as magnetospheric electric field and auroral precipitation. The possibility of coupling ionospheric models with thermospheric and magnetospheric models is examined.

  13. Online, automatic, ionospheric maps: IRI-PLAS-MAP

    NASA Astrophysics Data System (ADS)

    Arikan, F.; Sezen, U.; Gulyaeva, T. L.; Cilibas, O.

    2015-04-01

    Global and regional behavior of the ionosphere is an important component of space weather. The peak height and critical frequency of ionospheric layer for the maximum ionization, namely, hmF2 and foF2, and the total number of electrons on a ray path, Total Electron Content (TEC), are the most investigated and monitored values of ionosphere in capturing and observing ionospheric variability. Typically ionospheric models such as International Reference Ionosphere (IRI) can provide electron density profile, critical parameters of ionospheric layers and Ionospheric electron content for a given location, date and time. Yet, IRI model is limited by only foF2 STORM option in reflecting the dynamics of ionospheric/plasmaspheric/geomagnetic storms. Global Ionospheric Maps (GIM) are provided by IGS analysis centers for global TEC distribution estimated from ground-based GPS stations that can capture the actual dynamics of ionosphere and plasmasphere, but this service is not available for other ionospheric observables. In this study, a unique and original space weather service is introduced as IRI-PLAS-MAP from http://www.ionolab.org

  14. 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).

  15. 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.

  16. 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.

  17. Field-aligned electron density irregularities near 500 km. Equator to polar cap topside sounder Z mode observations

    NASA Technical Reports Server (NTRS)

    Benson, R. F.

    1984-01-01

    In addition to spread F, evidence for field-aligned electron density irregularities is commonly observed on Alouette 2 topside sounder ionograms recorded near perigee (500 km). This evidence is provided by distinctive signal returns from sounder-generated Z mode waves. At low latitudes these waves become guided in wave ducts caused by field-aligned electron density irregularities and give rise to strong long-duration echoes. At high latitudes, extending well into the polar cap, these Z mode waves (and stimulated electrostatic waves at the plasma frequency) produce a series of vertical bars on the ionogram display as the satellite traverses discrete field-aligned density structures. The radio frequency (RF) noise environment to be expected in the 400 to 500 km altitude region from low to high latitudes was examined by analyzing perigee Alouette 2 topside sounder data. All observed noise bands were scaled on nearly 200 topside sounder ionograms recorded near perigee at low, mid, and high latitude telemetry stations. The minimum and maximum frequencies of each noise band were entered into a data base or compuer analysis. The signals of primary interest in the perigee study were found to be sounder-generated.

  18. Impacts of Space Weather Effects on the Ionospheric Vertical Total Electron Content

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Space weather effects on the terrestrial ionospheric vertical total electron content (VTEC) are caused by solar EUV- and X-Ray emissions, solar wind streams and coronal mass ejections (CMEs), amongst other processes. They can lead to major disturbances of telecommunication and navigation systems.