Science.gov

Sample records for solar atmosphere implications

  1. Study of magnetic notions in the solar photosphere and their implications for heating the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Noyes, Robert W.

    1995-01-01

    This progress report covers the first year of NASA Grant NAGw-2545, a study of magnetic structure in the solar photosphere and chromosphere. We have made significant progress in three areas: (1) analysis of vorticity in photospheric convection, which probably affects solar atmospheric heating through the stresses it imposes on photospheric magnetic fields; (2) modelling of the horizontal motions of magnetic footpoints in the solar photosphere using an assumed relation between brightness and vertical motion as well as continuity of flow; and (3) observations and analysis of infrared CO lines formed near the solar temperature minimum, whose structure and dynamics also yield important clues to the nature of heating of the upper atmosphere. Each of these areas are summarized in this report, with copies of those papers prepared or published this year included.

  2. Implications of CHOOZ results for the decoupling of solar and atmospheric neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Bilenky, S. M.; Giunti, C.

    1998-12-01

    We have considered the results of solar and atmospheric neutrino oscillation experiments in the scheme of mixing of three neutrinos with a mass hierarchy. It is shown that (if m32-m12>10-3 eV2) the recent results of the CHOOZ experiment imply that Ue32≪1 (U is the neutrino mixing matrix), that the oscillations of solar neutrinos are described by the two-generation formalism and that the oscillations of solar and atmospheric neutrinos decouple. It is also shown that if not only Ue32≪1 but also Ue3≪1, then the oscillations of atmospheric neutrinos do not depend on matter effects and are described by the two-generation formalism. In this case, with an appropriate identification of the mixing parameters, the two-generation analyses of solar and atmospheric neutrino data provide direct information on the mixing parameters of three neutrinos. We discuss the possibility to get information on Ue32 in long-baseline neutrino oscillation experiments.

  3. Implications of solar irradiance variability upon long-term changes in the Earth's atmospheric temperatures

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III

    1992-01-01

    From 1979 through 1987, it is believed that variability in the incoming solar energy played a significant role in changing the Earth's climate. Using high-precision spacecraft radiometric measurements, the incoming total solar irradiance (total amount of solar power per unit area) and the Earth's mean, global atmospheric temperatures were found to vary in phase with each other. The observed irradiance and temperature changes appeared to be correlated with the 11-year cycle of solar magnetic activity. During the period from 1979 through 1985, both the irradiance and temperature decreased. From 1985 to 1987, they increased. The irradiance changed approximately 0.1 percent, while the temperature varied as much as 0.6 C. During the 1979-1987 period, the temperatures were forecasted to rise linearly because of the anthropogenic build-up of carbon dioxide and the hypothesized 'global warming', 'greenhouse effect', scenarios. Contrary to these scenarios, the temperatures were found to vary in a periodic manner in phase with the solar irradiance changes. The observed correlations between irradiance and temperature variabilily suggest that the mean, global temperature of the Earth may decline between 1990 and 1997 as solar magnetic activity decreases.

  4. Geology and photometric variation of solar system bodies with minor atmospheres: implications for solid exoplanets.

    PubMed

    Fujii, Yuka; Kimura, Jun; Dohm, James; Ohtake, Makiko

    2014-09-01

    A reasonable basis for future astronomical investigations of exoplanets lies in our best knowledge of the planets and satellites in the Solar System. Solar System bodies exhibit a wide variety of surface environments, even including potential habitable conditions beyond Earth, and it is essential to know how they can be characterized from outside the Solar System. In this study, we provide an overview of geological features of major Solar System solid bodies with minor atmospheres (i.e., the terrestrial Moon, Mercury, the Galilean moons, and Mars) that affect surface albedo at local to global scale, and we survey how they influence point-source photometry in the UV/visible/near IR (i.e., the reflection-dominant range). We simulate them based on recent mapping products and also compile observed light curves where available. We show a 5-50% peak-to-trough variation amplitude in one spin rotation associated with various geological processes including heterogeneous surface compositions due to igneous activities, interaction with surrounding energetic particles, and distribution of grained materials. Some indications of these processes are provided by the amplitude and wavelength dependence of variation in combinations of the time-averaged spectra. We also estimate the photometric precision needed to detect their spin rotation rates through periodogram analysis. Our survey illustrates realistic possibilities for inferring the detailed properties of solid exoplanets with future direct imaging observations. Key Words: Planetary environments-Planetary geology-Solar System-Extrasolar terrestrial planets.

  5. Geology and Photometric Variation of Solar System Bodies with Minor Atmospheres: Implications for Solid Exoplanets

    PubMed Central

    Kimura, Jun; Dohm, James; Ohtake, Makiko

    2014-01-01

    Abstract A reasonable basis for future astronomical investigations of exoplanets lies in our best knowledge of the planets and satellites in the Solar System. Solar System bodies exhibit a wide variety of surface environments, even including potential habitable conditions beyond Earth, and it is essential to know how they can be characterized from outside the Solar System. In this study, we provide an overview of geological features of major Solar System solid bodies with minor atmospheres (i.e., the terrestrial Moon, Mercury, the Galilean moons, and Mars) that affect surface albedo at local to global scale, and we survey how they influence point-source photometry in the UV/visible/near IR (i.e., the reflection-dominant range). We simulate them based on recent mapping products and also compile observed light curves where available. We show a 5–50% peak-to-trough variation amplitude in one spin rotation associated with various geological processes including heterogeneous surface compositions due to igneous activities, interaction with surrounding energetic particles, and distribution of grained materials. Some indications of these processes are provided by the amplitude and wavelength dependence of variation in combinations of the time-averaged spectra. We also estimate the photometric precision needed to detect their spin rotation rates through periodogram analysis. Our survey illustrates realistic possibilities for inferring the detailed properties of solid exoplanets with future direct imaging observations. Key Words: Planetary environments—Planetary geology—Solar System—Extrasolar terrestrial planets. Astrobiology 14, 753–768. PMID:25238324

  6. Interaction of cosmic and solar flare radiations with the Martian atmosphere and their biological implications.

    PubMed

    Yagoda, H

    1964-01-01

    Assuming a constant interplanetary flux of galactic cosmic radiation and a model planetary atmosphere, it is possible to evaluate the magnitude of secondary ionization phenomena therein from parameters measured on Earth. The Martian atmosphere is of particular interest as its total air mass, estimated between 354 and 109 g cm-2, is in the vicinity of the Pfotzer cosmic ray maximum. Assuming the absence of a magnetic field on Mars the maximum neutron production would occur at an atmospheric depth of 75 +/- 5 g cm-2. With the lower air mass limit the surface flux of neutrons reaching the Martian surface could be about 240 times greater than observed at Earth's sea level. Surface minerals containing nuclei with large capture cross sections for slow neutrons, such as Li6, B10 and U235, could thus serve as valuable indicators for the age of the Martian crust. In general, the tenuous Martian atmosphere would result in greater surface radiation dose rates, particularly during times of relativistic solar flares. If the surface air mass is as low as 109 g cm-2 then the rate of nuclear disintegrations due to galactic cosmic radiation would exceed that on Earth's sea level approximately 1000-fold. The tenuous Martian atmosphere would not be a complete shield for heavy primary nuclei and about 1 percent of the incident flux could reach the surface.

  7. Generation of Electron Suprathermal Tails in the Upper Solar Atmosphere: Implications for Coronal Heating

    NASA Technical Reports Server (NTRS)

    Vinas, Adolfo F.; Wong, Hung K.; Klimas, Alexander J.

    1999-01-01

    We present a mechanism for the generation of non-Maxwellian electron distribution function in the upper regions of the solar atmosphere in the presence of collisional damping. It is suggested that finite amplitude, low frequency, obliquely propagating electromagnetic waves can carry a substantial electric field component parallel to the mean magnetic field that can be significantly larger than the Dreicer electric field. This long wavelength electric fluctuation is capable of generating high frequency electron plasma oscillations and low frequency ion acoustic-like waves. The analysis has been performed using 1-1/2D Vlasov and PIC numerical simulations in which both electrons and ions are treated kinetically and self consistently. The simulation results indicate that high frequency electron plasma oscillations and low frequency ion acoustic-like waves are generated. The high frequency electron plasma oscillation drives electron plasma turbulence, which subsequently is damped out by the background electrons. The turbulence damping results in electron acceleration and the generation of non-Maxwellian suprathermal tails on time scales short compared to collisional damping. Bulk heating also occurs if the fluctuating parallel electric field is strong enough. This study suggests that finite amplitude, low frequency, obliquely propagating, electromagnetic waves can play a significant role in the acceleration and heating of the solar corona electrons and in the coupling of medium and small-scale phenomena.

  8. Solar atmosphere neutrino oscillations

    SciTech Connect

    Fogli, G.L.; Lisi, E.; Mirizzi, A.; Montanino, D.; Serpico, P.D.; /Fermilab

    2007-02-01

    The Sun is a source of high energy neutrinos (E > 10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations on the solar atmosphere neutrino fluxes observable at Earth. We find that peculiar matter oscillation effects in the Sun do exist, but are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged ''vacuum'' oscillations, dominated by a single mixing parameter (the angle {theta}{sub 23}).

  9. Variations in Solar Activity and Irradiance and Their Implications for Energy Input Into the Terrestrial Atmosphere

    NASA Astrophysics Data System (ADS)

    Parker, Daryl Gray

    This dissertation presents research into the question of how variations in the physical properties of resolved solar magnetic surface features combine to produce variations in the physical properties of the integrated Sun and the possible impacts of those variations on the terrestrial climate system. The core approach to the research was development of techniques to apply automated Bayesian statistical pattern recognition methods as implemented in the AutoClass software to magnetic and intensity-like solar images from the Mount Wilson Solar Observatory (MWO) 150 Foot Solar Telescope. The goals were to: (1) identify in an objective and quantifiable manner the solar surface features responsible for changes in solar irradiance, (2) enhance understanding of the evolution of these features and the resultant solar irradiance variations over the most recent solar cycles, (3) develop methods to identify the specific features responsible for variations in specific wavelengths, (4) use global observations of global solar irradiance indices to identify the spatially resolved features which contribute to them, (5) attempt to apply these results to specific topics of current interest in solar-stellar astronomy. Using these techniques, a method was developed to identify classes of features from thousands of MWO solar images based on the per pixel values of absolute magnetic field strength and an intensity measure known as a "ratio-gram" in MWO images. Using these classes along with observations from independent, usually satellite based, sources in different wavelengths, models were constructed of total solar irradiance (TSI) and solar UV indices. These models were able to reproduce with high correlations solar observations in a number of different solar wavelengths. These classes were also used to construct images mapping different wavelength emissions to the areas to the solar surface features from which they originated. These techniques proved able to reproduce with high

  10. Center-to-limb observations of the Sun with ALMA . Implications for solar atmospheric models

    NASA Astrophysics Data System (ADS)

    Alissandrakis, C. E.; Patsourakos, S.; Nindos, A.; Bastian, T. S.

    2017-09-01

    Aims: We seek to derive information on the temperature structure of the solar chromosphere and compare these results with existing models. Methods: We measured the center-to-limb variation of the brightness temperature, Tb, from ALMA full-disk images at two frequencies and inverted the solution of the transfer equation to obtain the electron temperature, Te as a function of optical depth, τ. Results: The ALMA images are very similar to AIA images at 1600 Å. The brightness temperature at the center of the disk is 6180 and 7250 K at 239 and 100 GHz, respectively, with dispersions of 100 and 170 K. Plage regions stand out clearly in the 239/100 GHz intensity ratio, while faculae and filament lanes do not. The solar disk radius, reduced to 1 AU, is 961.1 ± 2.5'' and 964.1 ± 4.5'' at 239 and 100 GHz, respectively. A slight but statistically significant limb brightening is observed at both frequencies. Conclusions: The inversion of the center-to-limb curves shows that Te varies linearly with the logarithm of optical depth for 0.34 <τ100 GHz< 12, with a slope dTe/ dlnτ = -608 K. Our results are 5% lower than predicted by the average quiet Sun model C of Fontenla et al. (1993, ApJ, 406, 319), but do not confirm previous reports that the mm-λ solar spectrum is better fitted with models of the cell interior.

  11. Solar flare model atmospheres

    NASA Technical Reports Server (NTRS)

    Hawley, Suzanne L.; Fisher, George H.

    1993-01-01

    Solar flare model atmospheres computed under the assumption of energetic equilibrium in the chromosphere are presented. The models use a static, one-dimensional plane parallel geometry and are designed within a physically self-consistent coronal loop. Assumed flare heating mechanisms include collisions from a flux of non-thermal electrons and x-ray heating of the chromosphere by the corona. The heating by energetic electrons accounts explicitly for variations of the ionized fraction with depth in the atmosphere. X-ray heating of the chromosphere by the corona incorporates a flare loop geometry by approximating distant portions of the loop with a series of point sources, while treating the loop leg closest to the chromospheric footpoint in the plane-parallel approximation. Coronal flare heating leads to increased heat conduction, chromospheric evaporation and subsequent changes in coronal pressure; these effects are included self-consistently in the models. Cooling in the chromosphere is computed in detail for the important optically thick HI, CaII and MgII transitions using the non-LTE prescription in the program MULTI. Hydrogen ionization rates from x-ray photo-ionization and collisional ionization by non-thermal electrons are included explicitly in the rate equations. The models are computed in the 'impulsive' and 'equilibrium' limits, and in a set of intermediate 'evolving' states. The impulsive atmospheres have the density distribution frozen in pre-flare configuration, while the equilibrium models assume the entire atmosphere is in hydrostatic and energetic equilibrium. The evolving atmospheres represent intermediate stages where hydrostatic equilibrium has been established in the chromosphere and corona, but the corona is not yet in energetic equilibrium with the flare heating source. Thus, for example, chromospheric evaporation is still in the process of occurring.

  12. VELOCITY-SHEAR-INDUCED MODE COUPLING IN THE SOLAR ATMOSPHERE AND SOLAR WIND: IMPLICATIONS FOR PLASMA HEATING AND MHD TURBULENCE

    SciTech Connect

    Hollweg, Joseph V.; Chandran, Benjamin D. G.; Kaghashvili, Edisher Kh. E-mail: ekaghash@aer.com

    2013-06-01

    We analytically consider how velocity shear in the corona and solar wind can cause an initial Alfven wave to drive up other propagating signals. The process is similar to the familiar coupling into other modes induced by non-WKB refraction in an inhomogeneous plasma, except here the refraction is a consequence of velocity shear. We limit our discussion to a low-beta plasma, and ignore couplings into signals resembling the slow mode. If the initial Alfven wave is propagating nearly parallel to the background magnetic field, then the induced signals are mainly a forward-going (i.e., propagating in the same sense as the original Alfven wave) fast mode, and a driven signal propagating like a forward-going Alfven wave but polarized like the fast mode; both signals are compressive and subject to damping by the Landau resonance. For an initial Alfven wave propagating obliquely with respect to the magnetic field, the induced signals are mainly forward- and backward-going fast modes, and a driven signal propagating like a forward-going Alfven wave but polarized like the fast mode; these signals are all compressive and subject to damping by the Landau resonance. A backward-going Alfven wave, thought to be important in the development of MHD turbulence, is also produced, but it is very weak. However, we suggest that for oblique propagation of the initial Alfven wave the induced fast-polarized signal propagating like a forward-going Alfven wave may interact coherently with the initial Alfven wave and distort it at a strong-turbulence-like rate.

  13. Response of Earth's Atmosphere to Increases in Solar Flux and Implications for Loss of Water from Venus

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.; Pollock, J. G.; Ackerman, T. P.

    1985-01-01

    A one dimensional radiative convective model is used to compute temperature and water vapor profiles as functions of solar flux for earthlike atmosphere. The troposphere is assumed to be fully saturated with a moist adiabatic lapse rate, and changes in cloudiness are neglected. Predicted surface temperatures increase monotonically from -1 to 111 C as the solar flux is increased from 0.81 to 1.45 times its present value. The results imply that the surface temperature of a primitive water rich Venus should have been at least 80-100 C and may have been much higher, water vapor should have been a major atmospheric constituent at all altitudes, leading to the rapid hydrodynamic escape of hydrogen. The oxygen left behind by this process was presumably consumed by reactions with reduced minerals in the crust.

  14. Response of earth's atmosphere to increases in solar flux and implications for loss of water from Venus

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.; Pollack, J. B.; Ackerman, T. P.

    1984-01-01

    A one-dimensional radiative-convective model is used to compute temperature and water vapor profiles as functions of solar flux for an earthlike atmosphere. The troposphere is assumed to be fully saturated, with a moist adiabatic lapse rate, and changes in cloudiness are neglected. Predicted surface temperatures increase monotonically from -1 to 111 C as the solar flux is increased from 0.81 to 1.45 times its present value. The results imply that the surface temperature of a primitive water-rich Venus should have been at least 80-100 C and may have been much higher. Water vapor should have been a major atmospheric constituent at all altitudes, leading to the rapid hydrodynamic escape of hydrogen. The oxygen left behind by this process was presumably consumed by reactions with reduced minerals in the crust.

  15. Atmospheric changes from solar eclipses.

    PubMed

    Aplin, K L; Scott, C J; Gray, S L

    2016-09-28

    This article reviews atmospheric changes associated with 44 solar eclipses, beginning with the first quantitative results available, from 1834 (earlier qualitative accounts also exist). Eclipse meteorology attracted relatively few publications until the total solar eclipse of 16 February 1980, with the 11 August 1999 eclipse producing the most papers. Eclipses passing over populated areas such as Europe, China and India now regularly attract scientific attention, whereas atmospheric measurements of eclipses at remote locations remain rare. Many measurements and models have been used to exploit the uniquely predictable solar forcing provided by an eclipse. In this paper, we compile the available publications and review a subset of them chosen on the basis of importance and novelty. Beyond the obvious reduction in incoming solar radiation, atmospheric cooling from eclipses can induce dynamical changes. Observations and meteorological modelling provide evidence for the generation of a local eclipse circulation that may be the origin of the 'eclipse wind'. Gravity waves set up by the eclipse can, in principle, be detected as atmospheric pressure fluctuations, though theoretical predictions are limited, and many of the data are inconclusive. Eclipse events providing important early insights into the ionization of the upper atmosphere are also briefly reviewed.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'.

  16. Oscillations of solar atmosphere neutrinos

    SciTech Connect

    Fogli, G. L.; Lisi, E.; Mirizzi, A.; Montanino, D.; Serpico, P. D.

    2006-11-01

    The Sun is a source of high-energy neutrinos (E(greater-or-similar sign)10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations (in vacuum and in matter) on solar atmosphere neutrinos, and calculate their observable fluxes at Earth, as well as their event rates in a kilometer-scale detector in water or ice. We find that peculiar three-flavor oscillation effects in matter, which can occur in the energy range probed by solar atmosphere neutrinos, are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, we find that the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged vacuum oscillations, dominated by a single mixing parameter (the angle {theta}{sub 23})

  17. Nonlinear waves in the solar atmosphere.

    PubMed

    Ruderman, Michael S

    2006-02-15

    In this paper, we give a brief review of the contemporary theory of nonlinear waves in the solar atmosphere. The choice of topics reflects personal interests of the author. Historically the theory of nonlinear waves was first applied to the solar atmosphere to explain the chromospheric and coronal heating. It was assumed that the turbulent motion in the solar convective zone excites sound waves that propagate upwards. Due to nonlinearity these waves steepen and form shocks. The wave energy dissipates in these shocks thus heating the corona. We give a brief description of propagation and damping of nonlinear sound waves in the stratified solar atmosphere, and point out that, at present, the acoustic heating remains the most popular theory of heating the lower chromosphere. Then we extend the analysis to nonlinear slow magnetosonic waves in coronal plumes and loops, and discuss its implications for interpretation of observational results. The next topic of interest is the propagation of nonlinear waves in a magnetically structured atmosphere. Here, we restrict our analysis to slow sausage waves in magnetic tubes and discuss properties of solitary waves described by the Leibovich-Roberts equation. We conclude with the discussion of nonlinear theory of slow resonant layers, and its possible application to helioseismology.

  18. Implications of the Detection of X-rays From Pluto by Chandra for Its Solar Wind - Neutral Atmosphere Interaction

    NASA Astrophysics Data System (ADS)

    Lisse, C. M.

    2016-12-01

    Using the Chandra X-Ray Observatory, we have obtained low-resolution imaging X-ray spectrophotometry of the Pluto system in support of the New Horizons (NH) flyby. In a total of 174 ksec of on-target time, we measured 8 photons from 0.31 to 0.60 keV in a co-moving 11 x 11 pixel2 box (the 90% flux aperture for fixed background sources in the field) measuring 121,000 x 121,000 km2 (or 100 x 100 RPluto) at Pluto. The Pluto photons do not have the spectral shape of the background, are coincident with a 90% flux aperture co-moving with Pluto, and are not confused with any background source, so we consider them as sourced from the Pluto system. Allowing for background, we find a net signal of 6.8 counts and a statistical noise level of 1.2 counts, for a detection of Pluto at > 99.95%. The mean 0.31 - 0.60 keV X-ray power from Pluto is 200 +200/-100 MW, in the middle range of X-ray power levels seen for other known solar system emission sources: auroral precipitation, solar X-ray scattering, and charge exchange (CXE) between solar wind (SW) ions and atmospheric neutrals. We eliminate auroral effects as a source, as Pluto has no known magnetic field and the NH/Alice UV spectrometer detected no airglow from Pluto during the flyby. Atmospheric haze particles could produce resonant scattering of solar X-rays from Pluto, but the energy signature of the detected photons does not match the solar spectrum and estimates of Pluto's scattered X-ray emission are 2 to 3 orders of magnitude lower than seen in our observations. CXE-driven emission from hydrogenic and heliogenic SW carbon, nitrogen, and oxygen ions can produce the energy signature seen, and the 6 x 1025 neutral gas escape rate from Pluto deduced from NH data (Gladstone et al. 2016) can support the 3.0 +3.0/-1.5 x 1024 X-ray photons/s emission rate required by our observations. Using the SW proton density and speed measured by the NH/SWAP instrument in the vicinity of Pluto at the time of the photon emissions, we find a

  19. Solar Absorption in Cloudy Atmospheres

    NASA Technical Reports Server (NTRS)

    Harshvardhan; Ridgway, William; Ramaswamy, V.; Freidenreich, S. M.; Batey, Michael

    1996-01-01

    The theoretical computations used to compute spectral absorption of solar radiation are discussed. Radiative properties relevant to the cloud absorption problem are presented and placed in the context of radiative forcing. Implications for future measuring programs and the effect of horizontal inhomogeneities are discussed.

  20. Energy transport through the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Harvey, K. L.; Harvey, J. W.

    1979-01-01

    The energy transport through the solar atmosphere and the source of energy which heats the chromosphere and the solar corona are studied. Wave propagation in the solar atmosphere and in the heating of the solar atmosphere is discussed as a source and transport medium. The source of the waves is thought to be the photospheric short period oscillations. Simultaneous observations from the photosphere to the corona at the solar disk center are reported. Emphasis is on the possible association of aperiodic brightenings high in the atmosphere with specific events in the photosphere.

  1. Cross-Scale Coupling in the Solar Atmosphere

    NASA Technical Reports Server (NTRS)

    Antiochos, Spiro K.

    2011-01-01

    For understanding and eventually predicting solar activity, the fundamental question that Solar-C must answer is: How does energy transfer from the large-scales at which it is injected into the solar atmosphere to the small scales at which it is dissipated? We show that this question of cross-scale coupling is fundamental to all activity, ranging from the smallest nanoflares that are postulated to power coronal heating and solar wind acceleration, to the largest coronal mass ejections and eruptive flares. For the solar atmosphere, the most important process that actually dissipates the energy is believed to be magnetic reconnection. We present results on recent calculations of reconnection in a variety of solar contexts and focus on the coupling between kinetic and MHD scales during reconnection. We discuss the implications of our results for present data and for future observations from Solar-C.

  2. Solar Atmosphere Simulation - AGU Dec. 9, 2013

    NASA Image and Video Library

    This movie shows a numerical simulation of a small area of the solar atmosphere at ~10,000K. Numerical models bridge the gap between IRIS observations and the physical mechanisms driving solar even...

  3. The Solar Spectrum: An Atmospheric Remote Sensing Perspective

    NASA Technical Reports Server (NTRS)

    Toon, Geoff

    2013-01-01

    The solar spectrum not only contains information about the composition and structure of the sun, it also provides a bright and stable continuum source for earth remote sensing (atmosphere and surface). Many types of remote sensors use solar radiation. While high-resolution spaceborne sensors (e.g. ACE) can largely remove the effects of the solar spectrum by exo-atmospheric calibration, this isn't an option for sub-orbital sensors, such as the FTIR spectrometers used in the NDACC and TCCON networks. In this case the solar contribution must be explicitly included in the spectral analysis. In this talk the methods used to derive the solar spectrum are presented, and the underlying solar physics are discussed. Implication for remote sensing are described.

  4. The Solar Spectrum: An Atmospheric Remote Sensing Perspective

    NASA Technical Reports Server (NTRS)

    Toon, Geoff

    2013-01-01

    The solar spectrum not only contains information about the composition and structure of the sun, it also provides a bright and stable continuum source for earth remote sensing (atmosphere and surface). Many types of remote sensors use solar radiation. While high-resolution spaceborne sensors (e.g. ACE) can largely remove the effects of the solar spectrum by exo-atmospheric calibration, this isn't an option for sub-orbital sensors, such as the FTIR spectrometers used in the NDACC and TCCON networks. In this case the solar contribution must be explicitly included in the spectral analysis. In this talk the methods used to derive the solar spectrum are presented, and the underlying solar physics are discussed. Implication for remote sensing are described.

  5. Solar storm effects on the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Brain, David; Lillis, Robert; Peticolas, Laura; Luhmann, Janet G.

    Solar storms, including solar flares, solar energetic particles (SEPs), and coronal mass ejections (CMEs), may have a profound influence on planetary atmospheres left unprotected by global magnetic fields, such as Mars and Venus. Energy deposited in the upper atmosphere by photons and charged particles during storms should contribute to ionization and heating, driving chemistry and dynamics over periods of hours or days. There is observational evidence that the escape rate of planetary ions from the Venus atmosphere can increase by an order of magnitude during a storm. The planetary plasma environment may also change considerably during a storm (for example compressing during a passing CME and leading to a strongly magnetized ionosphere). We will present observations and model calculations of the influence of solar energetic particle events and CMEs on the atmosphere of Mars, focusing on three areas. First, we will present a correlation between the energy of auroral-like electron distributions observed by the Mars Global Surveyor (MGS) spacecraft and the presence of solar energetic particles. We will use an electron transport model to calculate the influence of these electron distributions on the nightside atmosphere. Second, we will present an analysis of electron pitch angle distributions recorded by MGS during solar storms, showing a substantial increase in ionization resulting from SEP impact. Third, we will present model calculations of the atmospheric energy deposition by solar energetic particles during a storm.

  6. Atmospheric Electrification in the Solar System

    NASA Astrophysics Data System (ADS)

    Aplin, Karen L.

    2006-01-01

    Atmospheric electrification is not a purely terrestrial phenomenon: all Solar System planetary atmospheres become slightly electrified by cosmic ray ionisation. There is evidence for lightning on Jupiter, Saturn, Uranus and Neptune, and it is possible on Mars, Venus and Titan. Controversy surrounds the role of atmospheric electricity in physical climate processes on Earth; here, a comparative approach is employed to review the role of electrification in the atmospheres of other planets and their moons. This paper reviews the theory, and, where available, measurements, of planetary atmospheric electricity which is taken to include ion production and ion aerosol interactions. The conditions necessary for a planetary atmospheric electric circuit similar to Earth’s, and the likelihood of meeting these conditions in other planetary atmospheres, are briefly discussed. Atmospheric electrification could be important throughout the solar system, particularly at the outer planets which receive little solar radiation, increasing the relative significance of electrical forces. Nucleation onto atmospheric ions has been predicted to affect the evolution and lifetime of haze layers on Titan, Neptune and Triton. Atmospheric electrical processes on Titan, before the arrival of the Huygens probe, are summarised. For planets closer to Earth, heating from solar radiation dominates atmospheric circulations. However, Mars may have a global circuit analogous to the terrestrial model, but based on electrical discharges from dust storms. There is an increasing need for direct measurements of planetary atmospheric electrification, in particular on Mars, to assess the risk for future unmanned and manned missions. Theoretical understanding could be increased by cross-disciplinary work to modify and update models and parameterisations initially developed for a specific atmosphere, to make them more broadly applicable to other planetary atmospheres.

  7. Nucleosynthesis in the terrestrial and solar atmospheres

    NASA Technical Reports Server (NTRS)

    Yu, C.; Zhou, R.; Zhan, S.

    1985-01-01

    Variations of Delta D, delta C-13, Delta C-14 and Delta O-18 with time were measured by a lot of experiments. Many abnormalities of isotope abundances in cosmic rays were found by balloons and satellites. It is suggested that these abnormalities are related to nuclearsynthesis in the terrestrial and solar atmospheres and are closely related to solar activities.

  8. Solar-terrestrial relationships in atmospheric electricity

    SciTech Connect

    Roble, R.G.

    1985-06-30

    There are many suggested solar-terrestrial relationships in global atmospheric electricity. Of the various relationships, the downward mapping of ionospheric and magnetospheric electric fields, associated with the solar wind/magnetosphere and the ionosphere wind dynamos, is best understood theoretically and appears to be supported by the few available data. The solar cycle variations of ionospheric potential and air-earth current appear to be related to variations in galactic cosmic rays and perhaps to their effect on the current output from thunderstorms. The solar flare and solar magnetic sector boundary variations are not well understood but may be related to Forbush decreases in cosmic ray flux and/or effects resulting from energetic particle precipitation. The available data on auroral effects on atmospheric electricity are confusing and not understood at all. There is a clear need for further research to better define the physical mechanisms responsible for all of these solar-terrestrial relationships. The observed solar-terrestrial variations and the need for current closure in the global circuit suggest that the function of the equalization layer in the ''classical picture'' of atmospheric electricity should be revised to be consistent with our current knowledge of upper-atmospheric electrical processes.

  9. Sub-photosphere to Solar Atmosphere Connection

    NASA Astrophysics Data System (ADS)

    Komm, Rudolf; De Moortel, Ineke; Fan, Yuhong; Ilonidis, Stathis; Steiner, Oskar

    2015-12-01

    Magnetic fields extend from the solar interior through the atmosphere. The formation and evolution of active regions can be studied by measuring subsurface flows with local helioseismology. The emergence of magnetic flux from the solar convection zone is associated with acoustic perturbation signatures. In near-surface layers, the average dynamics can be determined for emerging regions. MHD simulations of the emergence of a twisted flux tube show how magnetic twist and free energy are transported from the interior into the corona and the dynamic signatures associated with such transport in the photospheric and sub-photospheric layers. The subsurface twisted flux tube does not emerge into the corona as a whole in emerging active regions. Shear flows at the polarity inversion line and coherent vortical motions in the subsurface flux tubes are the major means by which twist is transported into the corona, leading to the formation of sigmoid-shaped coronal magnetic fields capable of driving solar eruptions. The transport of twist can be followed from the interior by using the kinetic helicity of subsurface flows as a proxy of magnetic helicity; this quantity holds great promise for improving the understanding of eruptive phenomena. Waves are not only vital for studying the link between the solar interior and the surface but for linking the photosphere with the corona as well. Acoustic waves that propagate from the surface into the magnetically structured, dynamic atmosphere undergo mode conversion and refraction. These effects enable atmospheric seismology to determine the topography of magnetic canopies in the solar atmosphere. Inclined magnetic fields lower the cut-off frequency so that low frequency waves can leak into the outer atmosphere. Recent high resolution, high cadence observations of waves and oscillations in the solar atmosphere, have lead to a renewed interest in the potential role of waves as a heating mechanism. In light of their potential contribution

  10. Early Earth: Atmosphere's solar shock

    NASA Astrophysics Data System (ADS)

    Ramirez, Ramses

    2016-06-01

    Frequent storms on the young Sun would have ejected energetic particles and compressed Earth's magnetosphere. Simulations suggest that the particles penetrated the atmosphere and initiated reactions that warmed the planet and fertilized life.

  11. Solar geoengineering reduces atmospheric carbon burden

    NASA Astrophysics Data System (ADS)

    Keith, David W.; Wagner, Gernot; Zabel, Claire L.

    2017-09-01

    Solar geoengineering is no substitute for cutting emissions, but could nevertheless help reduce the atmospheric carbon burden. In the extreme, if solar geoengineering were used to hold radiative forcing constant under RCP8.5, the carbon burden may be reduced by ~100 GTC, equivalent to 12-26% of twenty-first-century emissions at a cost of under US$0.5 per tCO2.

  12. Vortex Identification in the Lower Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Fedun, V.; Giagkiozis, I.; Verth, G.; Scullion, E.

    2015-12-01

    Vortices in the solar atmosphere present an ideal driving mechanism for Alfvenic waves that can efficiently carry energy in the upper layers of the chromosphere and corona. However, the identification and classification of vortical motions from observations and numerical simulations is a challenging task. In this work we leverage a number of methods conventionally employed in turbulence to identify for the fist time in the solar atmosphere vortices, in an automated fashion. We also present a statistical analysis of the properties of the identified motions and relate this with theoretical results for such magnetic structures.

  13. Solar-terrestrial coupling through atmospheric electricity

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  14. Solar-terrestrial coupling through atmospheric electricity

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  15. Ninth Workshop 'Solar Influences on the Magnetosphere, Ionosphere and Atmosphere'

    NASA Astrophysics Data System (ADS)

    Georgieva, Kayta; Kirov, Boian; Danov, Dimitar

    2017-08-01

    The 9th Workshop "Solar Influences on the Magnetosphere, Ionosphere and Atmosphere" is an international forum for scientists working in the fields of: Sun and solar activity, Solar wind-magnetosphere-ionosphere interactions, Solar influences on the lower atmosphere and climate, Solar effects in the biosphere, Instrumentation for space weather monitoring and Data processing and modelling.

  16. Venus Atmospheric Exploration by Solar Aircraft

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; LaMarre, C.; Colozza, A.

    2002-01-01

    The Venus atmosphere is a favorable environment for flying powered aircraft. The atmospheric pressure makes flight much easier than on planets such as Mars. Above the clouds, solar energy is available in abundance on Venus, and the slow rotation of Venus allows a solar airplane to be designed for flight within continuous sunlight. The atmosphere between 50 km and 75 km on Venus is one of the most dynamic and interesting regions of the planet. The challenge for a Venus aircraft will be the fierce winds and caustic atmosphere. In order to remain on the sunlit side of Venus, an exploration aircraft will have to be capable of sustained flight at or above the wind speed. An aircraft would be a powerful tool for exploration. By learning how Venus can be so similar to Earth, and yet so different, we will learn to better understand the climate and geological history of the Earth.

  17. Solar forcing of the polar atmosphere

    NASA Astrophysics Data System (ADS)

    Mayewski, Paul Andrew; Maasch, Kirk A.; Yan, Yuping; Kang, Shichang; Meyerson, Eric A.; Sneed, Sharon B.; Kaspari, Susan D.; Dixon, Daniel A.; Osterberg, Erich C.; Morgan, Vin I.; van Ommen, Tas; Curran, Mark A. J.

    We present highly resolved, annually dated, calibrated proxies for atmospheric circulation from several Antarctic ice cores (ITASE (International Trans-Antarctic Scientific Expedition), Siple Dome, Law Dome) that reveal decadal-scale associations with a South Pole ice-core 10Be proxy for solar variability over the last 600 years and annual-scale associations with solar variability since AD 1720. We show that increased (decreased) solar irradiance is associated with increased (decreased) zonal wind strength near the edge of the Antarctic polar vortex. The association is particularly strong in the Indian and Pacific Oceans and as such may contribute to understanding climate forcing that controls drought in Australia and other Southern Hemisphere climate events. We also include evidence suggestive of solar forcing of atmospheric circulation near the edge of the Arctic polar vortex based on ice-core records from Mount Logan, Yukon Territory, Canada, and both central and south Greenland as enticement for future investigations. Our identification of solar forcing of the polar atmosphere and its impact on lower latitudes offers a mechanism for better understanding modern climate variability and potentially the initiation of abrupt climate-change events that operate on decadal and faster scales.

  18. Atmospheric Solar Heating in Minor Absorption Bands

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah

    1998-01-01

    Solar radiation is the primary source of energy driving atmospheric and oceanic circulations. Concerned with the huge computing time required for computing radiative transfer in weather and climate models, solar heating in minor absorption bands has often been neglected. The individual contributions of these minor bands to the atmospheric heating is small, but collectively they are not negligible. The solar heating in minor bands includes the absorption due to water vapor in the photosynthetically active radiation (PAR) spectral region from 14284/cm to 25000/cm, the ozone absorption and Rayleigh scattering in the near infrared, as well as the O2 and CO2 absorption in a number of weak bands. Detailed high spectral- and angular-resolution calculations show that the total effect of these minor absorption is to enhance the atmospheric solar heating by approximately 10%. Depending upon the strength of the absorption and the overlapping among gaseous absorption, different approaches are applied to parameterize these minor absorption. The parameterizations are accurate and require little extra time for computing radiative fluxes. They have been efficiently implemented in the various atmospheric models at NASA/Goddard Space Flight Center, including cloud ensemble, mesoscale, and climate models.

  19. Pulse beam heating of the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Karlicky, Marian

    1990-12-01

    A response of the solar atmosphere to pulse beam heating is computed using a one-dimensional hybrid code. While the hydrodynamic part of this program is used to compute the atmospheric response, the pulse beam decelerated by electron-electron and electron-neutral hydrogen interactions in the dense layers of the solar atmosphere is represented by particles. In this new description of an electron beam, the finite transit time of accelerated electrons in the flare loops is taken into account and the hard X-ray radiation is computed directly. Four different pulse beams are considered and their effects are compared. Moreover, the return current losses of the pulse beam are discussed.

  20. The Solar Atmosphere and Space Weather

    NASA Astrophysics Data System (ADS)

    Bothmer, Volker

    First ideas about possible physical influences of the Sun on Earth other than by electromagnetic (EM) radiation were scientifically discussed more seriously after Richard Carrington's famous observation of a spectacular white-light flare in 1859 and the subsequent conclusion that this flash of EM radiation was connected with the origin of strong perturbations of the Earth's outer magnetic field, commonly referred to as geomagnetic storms, which were recorded about 24 hours after the solar flare. Tentatively significant correlations of the number of geomagnetic storms and aurorae with the varying number of sunspots seen on the visible solar disk were found in the long-term with respect to the roughly 11-year periodicity of the solar activity cycle. Although theories of sporadic solar eruptions were postulated soon after the Carrington observations, the physical mechanism of the transfer of energy from the Sun to the Earth remained unknown. Early in the 20th century Chapman and Ferraro proposed the concept of huge clouds of charged particles emitted by the Sun as the triggers of geomagnetic storms. Based on the inference of the existence of a solar magnetic field, magnetized plasma clouds were subsequently introduced. Eugene Parker derived theoretical evidence for a continuous stream of ionized particles, the solar wind, leading to continuous convection of the Sun's magnetic field into interplanetary space. The existence of the solar wind was confirmed soon after the launch of the first satellites. Since then the Sun is known to be a permanent source of particles filling interplanetary space. However, it was still thought that the Sun's outer atmosphere, the solar corona, is a static rather than a dynamic object, undergoing only long-term structural changes in phase with the Sun's activity cycle. This view completely changed after space borne telescopes provided extended series of solar images in the EUV and soft X-ray range of the EM spectrum, invisible to ground

  1. On Wave Processes in the Solar Atmosphere

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.

    1998-01-01

    This grant was awarded by NASA/MSFC to The University of Alabama in Huntsville (UAH) to investigate the physical processes responsible for heating and wind acceleration in the solar atmosphere, and to construct theoretical, self-consistent and time-dependent solar wind models based on the momentum deposition by finite amplitude and nonlinear Alfven waves. In summary, there are three main goals of the proposed research: (1) Calculate the wave energy spectra and wave energy fluxes carried by magnetic non- magnetic waves. (2) Find out which mechanism dominates in supplying the wave energy to different parts of the solar atmosphere. (3) Use the results obtained in (1) and (2) to construct theoretical, self-consistent and time- dependent models of the solar wind. We have completed the first goal by calculating the amount of non-radiative energy generated in the solar convection zone as acoustic waves and as magnetic tube waves. To calculate the amount of wave energy carried by acoustic waves, we have used the Lighthill-Stein theory for sound generation modified by Musielak, Rosner, Stein & Ulmschneider (1994). The acoustic wave energy fluxes for stars located in different regions of the Hertzsprung-Russell (H-R) diagram have also been computed. The wave energy fluxes carried by longitudinal and transverse waves along magnetic flux tubes have been calculated by using both analytical and numerical methods. Our analytical approach is based a theory developed by Musielak, Rosner & Ulmschnelder and Musielak, Rosner, Gall & Ulmschneider, which allows computing the wave energy fluxes for linear tube waves. A numerical approach has been developed by Huang, Musielak & Ulmschneider and Ulmschneider & Musielak to compute the energy fluxes for nonlinear tube waves. Both methods have been used to calculate the wave energy fluxes for stars located in different regions of the HR diagram (Musielak, Rosner & Ulmschneider 1998; Ulmschneider, Musielak & Fawzy 1998). Having obtained the

  2. Determining solar effects in Neptune's atmosphere

    PubMed Central

    Aplin, K. L.; Harrison, R. G.

    2016-01-01

    Long-duration observations of Neptune's brightness at two visible wavelengths provide a disk-averaged estimate of its atmospheric aerosol. Brightness variations were previously associated with the 11-year solar cycle, through solar-modulated mechanisms linked with either ultraviolet or galactic cosmic ray (GCR) effects on atmospheric particles. Here, we use a recently extended brightness data set (1972–2014), with physically realistic modelling to show, rather than alternatives, ultraviolet and GCR are likely to be modulating Neptune's atmosphere in combination. The importance of GCR is further supported by the response of Neptune's atmosphere to an intermittent 1.5- to 1.9-year periodicity, which occurred preferentially in GCR (not ultraviolet) during the mid-1980s. This periodicity was detected both at Earth, and in GCR measured by Voyager 2, then near Neptune. A similar coincident variability in Neptune's brightness suggests nucleation onto GCR ions. Both GCR and ultraviolet mechanisms may occur more rapidly than the subsequent atmospheric particle transport. PMID:27417301

  3. Wave heating of the solar atmosphere

    PubMed Central

    Arregui, Iñigo

    2015-01-01

    Magnetic waves are a relevant component in the dynamics of the solar atmosphere. Their significance has increased because of their potential as a remote diagnostic tool and their presumed contribution to plasma heating processes. We discuss our current understanding of coronal heating by magnetic waves, based on recent observational evidence and theoretical advances. The discussion starts with a selection of observational discoveries that have brought magnetic waves to the forefront of the coronal heating discussion. Then, our theoretical understanding of the nature and properties of the observed waves and the physical processes that have been proposed to explain observations are described. Particular attention is given to the sequence of processes that link observed wave characteristics with concealed energy transport, dissipation and heat conversion. We conclude with a commentary on how the combination of theory and observations should help us to understand and quantify magnetic wave heating of the solar atmosphere. PMID:25897091

  4. Planetary atmospheric physics and solar physics research

    NASA Technical Reports Server (NTRS)

    1973-01-01

    An overview is presented on current and planned research activities in the major areas of solar physics, planetary atmospheres, and space astronomy. The approach to these unsolved problems involves experimental techniques, theoretical analysis, and the use of computers to analyze the data from space experiments. The point is made that the research program is characterized by each activity interacting with the other activities in the laboratory.

  5. Influence of solar activity on Jupiter's atmosphere

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.

    2016-05-01

    The influx of solar energy to different latitudes while Jupiter's orbital motion around the Sun varies significantly. This leads to a change in the optical and physical characteristics of its atmosphere. Analysis of the data for 1850-1991 on determination of the integral magnitude Mj Jupiter in the V filter, and a comparison with the changes of the Wolf numbers W, characterizing the variations of solar activity (SA) - showed that the change of Mj in maxima of the SA - has minima for odd, and maximums - for the even of SA cycles. That is, changing of the Jupiter brightness in visible light is much evident 22.3-year magnetic cycle, and not just about the 11.1-year cycle of solar activity. Analysis of the obtained in 1960-2015 data on the relative distribution of brightness along the central meridian of Jupiter, for which we calculated the ratio of the brightness Aj of northern to the southern part of the tropical and temperate latitudinal zones, allowed to approximate the change of Aj by sinusoid with a period of 11.91±0.07 earth years. Comparison of time variation of Aj from changes in the index of SA R, and the movement of the planet in its orbit - indicates the delay of response of the visible cloud layer in the atmosphere of the Sun's exposure mode for 6 years. This value coincides with the radiative relaxation of the hydrogen-helium atmosphere

  6. Dynamics of magnetic bright points in the lower solar atmosphere

    NASA Astrophysics Data System (ADS)

    Jafarzadeh, Shahin

    2013-08-01

    In this thesis we have investigated the structure and dynamics of small-scale magnetic bright points (MBPs) in quiet, internetwork regions of the lower solar atmosphere. Such MBPs are associated with small-scale, intense (generally kG) magnetic elements. The internetwork (IN) areas cover the largest fraction of the solar surface and it has been argued that the IN may contain most of the existing unsigned magnetic flux on the surface at any given time. However, the distribution of the magnetic field's properties in the IN regions is still being debated. Thus, only recently has the presence of kG fields in the IN been confirmed of which the studied MBPs are thought to be manifestations. In addition, interaction between intense magnetic features and convective flows on the solar surface (in particular in IN areas) have been proposed to excite waves which can carry energy to the upper solar atmosphere. The properties of these waves and their contribution to the heating of the upper solar atmosphere is still unclear. Moreover, the migration of the small magnetic elements owing to the convective flows/turbulence is not known (due to, e.g., lack of high spatial and temporal resolution observations not affected by seeing). We used high spatial and temporal resolution observations, obtained by the Sunrise balloon-borne solar observatory, to address the above issues. We concentrate on the study of the smallest MBPs visible in the data; whose apparent lack of internal fine-structure facilitates their precise location and tracking in time-series of images. The analyses were performed using an algorithm we developed to identify, locate and track the MBPs as well as to determine their physical properties at any given time. These findings have implications for, e.g., our understanding of the heating mechanisms in the higher layers of the solar atmosphere, estimates of the solar magnetic flux as well as the structure of the convection flows (within a supergranule) advecting small

  7. Atmospheric Renewable Energy Research, Volume 3: Solar-Power Microgrids and Atmospheric Influences

    DTIC Science & Technology

    2016-09-01

    ARL-TR-7797 ● SEP 2016 US Army Research Laboratory Atmospheric Renewable Energy Research, Volume 3: Solar-Power Microgrids and...Research Laboratory Atmospheric Renewable Energy Research, Volume 3: Solar-Power Microgrids and Atmospheric Influences by Gail Vaucher and...AND SUBTITLE Atmospheric Renewable Energy Research, Volume 3: Solar-Power Microgrids and Atmospheric Influences 5a. CONTRACT NUMBER 5b. GRANT

  8. Atmospheric scattering corrections to solar radiometry

    NASA Technical Reports Server (NTRS)

    Box, M. A.; Deepak, A.

    1979-01-01

    Whenever a solar radiometer is used to measure direct solar radiation, some diffuse sky radiation invariably enters the detector's field of view along with the direct beam. Therefore, the atmospheric optical depth obtained by the use of Bouguer's transmission law (also called Beer-Lambert's law), that is valid only for direct radiation, needs to be corrected by taking account of the scattered radiation. This paper discusses the correction factors needed to account for the diffuse (i,e., singly and multiply scattered) radiation and the algorithms developed for retrieving aerosol size distribution from such measurements. For a radiometer with a small field of view (half-cone angle of less than 5 deg) and relatively clear skies (optical depths less than 0.4), it is shown that the total diffuse contribution represents approximately 1% of the total intensity.

  9. Cloud geometry effects on atmospheric solar absorption

    SciTech Connect

    Fu, Q.; Cribb, M.C.; Barker, H.W.; Krueger, S.K.; Grossman, A.

    2000-04-15

    A 3D broadband solar radiative transfer scheme is formulated by integrating a Monte Carlo photon transport algorithm with the Fu-Liou radiation model. It is applied to fields of tropical mesoscale convective clouds and subtropical marine boundary layer clouds that were generated by a 2D cloud-resolving model. The effects of cloud geometry on the radiative energy budget are examined by comparing the full-resolution Monte Carlo results with those from the independent column approximation (ICA) that applies the plane-parallel radiation model to each column. For the tropical convective cloud system, it is found that cloud geometry effects always enhance atmospheric solar absorption regardless of solar zenith angle. In a large horizontal domain (512 km), differences in domain-averaged atmospheric absorption between the Monte Carlo and the ICA are less than 4 W m{sup {minus}2} in the daytime. However, for a smaller domain (e.g., 75 km) containing a cluster of deep convective towers, domain-averaged absorption can be enhanced by more than 20 W m{sup {minus}2}. For a subtropical marine boundary layer cloud system during the stratus-to-cumulus transition, calculations show that the ICA works very well for domain-averaged fluxes of the stratocumulus cloud fields even for a very small domain (4.8 km). For the trade cumulus cloud field, the effects of cloud sides and horizontal transport of photons become more significant. Calculations have also been made for both cloud systems including black carbon aerosol and a water vapor continuum. It is found that cloud geometry produces no discernible effects on the absorption enhancement due to the black carbon aerosol and water vapor continuum. The current study indicates that the atmospheric absorption enhancement due to cloud-related 3D photon transport is small. This enhancement could not explain the excess absorption suggested by recent studies.

  10. Solar faculae and waves propagating in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Pulyaev, V. A.; Kobanov, N. I.; Chupin, S. A.

    2011-12-01

    Solar faculae are among the most common manifestations of solar activity and can play an important role in the energy transfer from the lower solar atmosphere into the corona. However, the mechanisms by which energy is transferred remain insufficiently studied. Our work is based on observational data obtained with the AST telescope of the Sayan solar observatory. Simultaneous observations were performed in the Hα 6563 Å and FeI 6569 Å, BaII 4554 Å and FeI 4551.6 Å, and CaII 8542 Å and FeI 8538 Å pairs of spectral lines. The studies indicated that the spectral composition of the line-of-sight (LOS) velocity oscillations in faculae is inhomogeneous and is affected by the chromospheric network's structural elements. The possible presence of short and low magnetic loops in the facula region makes it difficult to determine the unambiguous phase relations between chromospheric and photospheric oscillations. The LOS velocity oscillation signals registered at the chromospheric level both lead and lag behind the signals registered at the photospheric level. At the same time, signs of propagating waves are evidently registered in the chromosphere of individual faculae.

  11. Coronal propagation: Variations with solar longitude and latitude. [astronomical models of the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Wibberenz, G.

    1976-01-01

    Observational results on the East-West effect are summarized and discussed in the context of existing models of coronal propagation. The variation of the number of events with solar longitude is shown to be surprisingly similar for particles covering a large interval of rigidities. Also, over large longitudinal distances, time delays to the event onset and maximum intensity are independent of energy and velocity. This has important implications and will require probably a transport process which is determined by fundamental properties of solar magnetic fields, e.g. reconnection processes between open and closed field configurations. The relative role of open and closed field configurations is extensively discussed. Some evidence is presented that the acceleration of protons to higher (approximately 10 MeV) energies is related with a shock wave traveling in the solar atmosphere. The importance of measurements performed from spacecraft out-of-the-ecliptic plane is stressed.

  12. Solar and atmospheric forcing on mountain lakes.

    PubMed

    Luoto, Tomi P; Nevalainen, Liisa

    2016-10-01

    We investigated the influence of long-term external forcing on aquatic communities in Alpine lakes. Fossil microcrustacean (Cladocera) and macrobenthos (Chironomidae) community variability in four Austrian high-altitude lakes, determined as ultra-sensitive to climate change, were compared against records of air temperature, North Atlantic Oscillation (NAO) and solar forcing over the past ~400years. Summer temperature variability affected both aquatic invertebrate groups in all study sites. The influence of NAO and solar forcing on aquatic invertebrates was also significant in the lakes except in the less transparent lake known to have remained uniformly cold during the past centuries due to summertime snowmelt input. The results suggest that external forcing plays an important role in these pristine ecosystems through their impacts on limnology of the lakes. Not only does the air temperature variability influence the communities but also larger-scale external factors related to atmospheric circulation patterns and solar activity cause long-term changes in high-altitude aquatic ecosystems, through their connections to hydroclimatic conditions and light environment. These findings are important in the assessment of climate change impacts on aquatic ecosystems and in greater understanding of the consequences of external forcing on lake ontogeny. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Solar Oscillations and the Magnetic Atmosphere

    NASA Astrophysics Data System (ADS)

    Taroyan, Y.; Doyle, J. G.

    2004-06-01

    With the launch of the SOHO and TRACE satellites two new branches of solar physics have emerged: time-distance helioseismology and coronal seismology. In time-distance helioseismology the travel time of the acoustic waves between different points on the solar surface is measured to infer the local structure and properties of the subsurface layers of the Sun. The travel time changes due to the atmospheric magnetic field are evaluated theoretically. Coronal seismology utilises MHD waves in solar coronal structures as a tool to diagnose the physical parameters of the coronal plasma. Theoretical modelling of recently observed slow standing mode oscillations in stratified loops is presented. It is shown that large-amplitude resonant standing waves can be driven by small-amplitude oscillations at the chromospheric footpoints of the loops. The periods and the behaviour of these waves are different from those predicted by the classical theory of isothermal loop oscillations. The possible relationsheep between the oscillations studied in time-distance helioseismology and in coronal seismology is addressed.

  14. Atmospheric scattering corrections to solar radiometry.

    PubMed

    Box, M A; Deepak, A

    1979-06-15

    Whenever a solar radiometer is used to measure direct solar radiation, some diffuse sky radiation invariably enters the detector's field of view along with the direct beam. Therefore, the atmospheric optical depth obtained by the use of Bouguer's transmission law (also called Beer-Lambert's law), that is valid only for direct radiation, needs to be corrected by taking account of the scattered radiation. In this paper we shall discuss the correction factors needed to account for the diffuse (i.e., singly and multiply scattered) radiation and the algorithms developed for retrieving aerosol size distribution from such measurements. For a radiometer with a small field of view (half-cone angle < 5 degrees ) and relatively clear skies (optical depths < 0.4), it is shown that the total diffuse contribution represents approximately 1% of the total intensity. It is assumed here that the main contributions to the diffuse radiation within the detector's view cone are due to single scattering by molecules and aerosols and multiple scattering by molecules alone, aerosol multiple scattering contributions being treated as negligibly small. The theory and the numerical results discussed in this paper will be helpful not only in making corrections to the measured optical depth data but also in designing improved solar radiometers.

  15. VENUS Atmospheric Exploration by Solar Aircraft

    NASA Astrophysics Data System (ADS)

    Landis, G. A.; Lamarre, C.; Colozza, A.

    2002-01-01

    much easier than on planets such as Mars. Above the clouds, solar energy is available in abundance on Venus. Venus has a solar flux of 2600 W/m2, compared to Earth's 1370 W/m2. The solar intensity is 20 to 50% of the exoatmospheric intensity (depending on wavelength) at the bottom of the cloud layer at 50 km, and increases to nearly 95% of the exoatmospheric intensity at 65 km, the top of the main cloud layer, and the slow rotation of Venus allows an airplane to be designed for flight within continuous sunlight, eliminating the need for energy storage for nighttime flight. challenge for a Venus aircraft will be the fierce winds and caustic atmosphere. The wind reaches a speed of about 95m/s at the cloud top level, and in order to remain on the sunlit side of Venus, an exploration aircraft will have to be capable of sustained flight at or above the wind speed. desirable that the number of moving parts be minimized. Figure 1 shows a concept for a Venus airplane design that requires only two folds to fold the wing into an aeroshell, and no folds to deploy the tail. Because of the design constraint that the two- fold wing is to fit into a small aeroshell, the wing area is maximum at extremely low aspect ratio, and higher aspect ratios can be achieved only by reducing the wing area. To fit the circular aeroshell, the resulting design trade-off increases wing area by accepting the design compromise of an extremely short tail moment and small tail area (stabilizer area 9% of wing area). In terms of flight behavior, the aircraft is essentially a flying wing design with the addition of a small control surface. A more conventional aircraft design can be made by folding or telescoping the tail boom as well as the wing. Typical flight altitudes for analysis were 65 to 75 km above the surface. For exploration of lower altitudes, it is feasible to glide down to low altitudes for periods of several hours, accepting the fact that the airplane ground track will blow downwind, and

  16. Atmospheric planetary waves induced by solar rotation

    NASA Technical Reports Server (NTRS)

    Krivolutsky, A. A.

    1989-01-01

    It is known that there are variations in the atmospheric processes with a period close to that of the rotation of the Sun (27 days). The variations are discovered in tropospheric processes, rainfalls, geopotential and in stratosphere. The main theoretical problem is the identification of the physical process by which these heterogeneous solar and meteorological phenomena are connected. Ivanovsky and Krivolutsky proposed that the periodic heating of the ozone layer by the short wave radiation would be the reason of excitation the 27-day oscillations. It was also assumed that excitement takes place in condition of resonance with an excited mode corresponding to the conditions present in the stratospheric circulations. The possibility is discussed of the resonant excitation and presentation is made of the data analysis results which support this idea.

  17. Waves and Magnetism in the Solar Atmosphere (WAMIS)

    NASA Astrophysics Data System (ADS)

    Strachan, L.; Ko, Y.-K.; Moses, J. D.; Laming, J. M.; Auchere, F.; Casini, R.; Fineschi, S.; Gibson, S.; Knoelker, M.; Korendyke, C.; Mcintosh, S.; Romoli, M.; Rybak, J.; Socker, D.; Tomczyk, S.; Vourlidas, A.; Wu, Q.

    2015-10-01

    Magnetic fields in the solar atmosphere provide the energy for most varieties of solar activity, including high-energy electromagnetic radiation, solar energetic particles, flares, and coronal mass ejections, as well as powering the solar wind. Despite the fundamental role of magnetic fields in solar and heliospheric physics, there exist only very limited measurements of the field above the base of the corona. What is needed are direct measurements of not only the strength and orientation of the magnetic field but also the signatures of wave motions in order to better understand coronal structure, solar activity, and the role of MHD waves in heating and accelerating the solar wind. Fortunately, the remote sensing instrumentation used to make magnetic field measurements is also well suited to measure the Doppler signature of waves in the solar structures. We present here a mission concept for the Waves And Magnetism In the Solar Atmosphere (WAMIS) experiment which is proposed for a NASA long-duration balloon flight.

  18. The reaction of the atmosphere to solar disturbances

    NASA Technical Reports Server (NTRS)

    Mikhnevich, V. V.

    1979-01-01

    The effect of solar flares on the thermosphere and the troposphere is investigated. It is found that during periods of geoeffect solar disturbances, there is a connection between phenomena in the upper and lower atmospheres and that variations in atmospheric parameters correlate with changes in the geomagnetic index.

  19. Semidiurnal solar tides in the mountain atmosphere

    SciTech Connect

    Whiteman, C.D.; Bian, X.

    1994-09-01

    Harmonic analysis of Doppler radar wind profiler data west of the Rocky Mountains has identified a coherent semidiurnal wind system above the wintertime boundary layer at multiple sites in the region. The unusual characteristics of this mountain wind system (its semidiurnal frequency, amplitude, phase, and direction of rotation) suggest that is is a semidiurnal solar tide. Such tides have not been previously documented in the mountain atmosphere or in the troposphere generally but, because semidiurnal signatures are well known in surface barometric traces, and large amplitude semidiurnal tides are known in the upper atmosphere, they are not unexpected. Our future research on this semidiurnal cordilleran wind system will focus on obtaining sufficient data to resolve further the vertical structure, seasonal variation, and spatial variations of the wind system. Of particular interest is the role of the Rocky Mountains and other cordilleras in modifying the global tides. It remains to be seen whether semidiurnal cordilleran circulations will be of sufficient magnitude to be observed across major arcuate-shaped east-west-oriented mountain massifs such as the Alps. There, wind systems may develop in response to pressure gradients (Frei and Davies, 1993) that form across the Alps due to differences in the amplitudes and phases of semidiurnal and diurnal pressure oscillations on the north and south sides of the mountain barrier.

  20. Ultraviolet Spectral Comparison of "Quiescent" M-dwarf Flares with Solar and "Active" M-dwarf Flares and the Implications for an Earth-like Atmosphere

    NASA Astrophysics Data System (ADS)

    Parke Loyd, R. O.; France, Kevin; Youngblood, Allison

    2015-08-01

    All flares are not created equal. In particular, flares on low-mass stars are notable for their diversity, even between events on the same star. To better characterize these differences and the range of flare morphologies possible on low-mass stars, we analyzed a sample of such flares in detail using temporally resolved UV spectroscopy from the growing body of MUSCLES Treasury Survey data. Specifically, we used the data to analyze the response of several UV emission lines (e.g. C II, Si III, Si IV) and the UV continuum following each impulsive event. From this analysis, we present a qualitative picture of energy deposition and propagation in the stellar atmosphere during a few representative events. These data also permitted a spectral comparison with flares typical of the Sun, and we describe the most prominent differences that emerged from this comparison. Additionally, by including flares from all the observed MUSCLES stars, we create an energy-frequency plot for flares on “quiescent” M-dwarfs and compare it to that of the Sun and of well-studied “active” M-dwarfs such as AD Leo. Flares like those we detected and analyzed can strip some atmosphere from closely orbiting planets, adversely affecting the long-term habitability of planets that might have initially supported liquid surface water. To gauge the amplitude of this effect, we used the flare data to make an empirically driven estimate of how much mass each representative flare might remove from the atmosphere of an Earth-like planet.

  1. Implications of solar wind measurements for solar models and composition

    NASA Astrophysics Data System (ADS)

    Serenelli, Aldo; Scott, Pat; Villante, Francesco L.; Vincent, Aaron C.; Asplund, Martin; Basu, Sarbani; Grevesse, Nicolas; Peña-Garay, Carlos

    2016-11-01

    We critically examine recent claims of a high solar metallicity by von Steiger & Zurbuchen (2016, vSZ16) based on in situ measurements of the solar wind, rather than the standard spectroscopically inferred abundances (Asplund et al. 2009, hereafter AGSS09). We test the claim by Vagnozzi et al. (2016) that a composition based on the solar wind enables one to construct a standard solar model in agreement with helioseismological observations and thus solve the decades-old solar modelling problem. We show that, although some helioseismological observables are improved compared to models computed with spectroscopic abundances, most are in fact worse. The high abundance of refractory elements leads to an overproduction of neutrinos, with a predicted 8B flux that is nearly twice its observed value, and 7Be and CNO fluxes that are experimentally ruled out at high confidence. A combined likelihood analysis shows that models using the vSZ16 abundances are worse than AGSS09 despite a higher metallicity. We also present astrophysical and spectroscopic arguments showing the vSZ16 composition to be an implausible representation of the solar interior, identifying the first ionization potential effect in the outer solar atmosphere and wind as the likely culprit.

  2. Magnetic reconnection in incompressible fluids. [of solar atmosphere and interior

    NASA Technical Reports Server (NTRS)

    Deluca, Edward E.; Craig, Ian J.

    1992-01-01

    The paper investigates the dynamical relaxation of a disturbed X-type magnetic neutral point in a periodic geometry, with an ignorable coordinate, for an incompressible fluid. It is found that the properties of the current sheet cannot be understood in terms of steady state reconnection theory or more recent linear dynamical solutions. Accordingly, a new scaling law for magnetic reconnection is presented, consistent with fast energy dissipation (i.e., the dissipation rate at current maximum is approximately independent of magnetic diffusivity (eta)). The flux annihilation rate, however, scales at eta exp 1/4, faster than the Sweet-Parker rate of sq rt eta but asymptotically much slower than the dissipation rate. These results suggest a flux pile-up regime in which the bulk of the free magnetic energy is released as heat rather than as kinetic energy of mass motion. The implications of our results for reconnection in the solar atmosphere and interior are discussed.

  3. Little or no solar wind enters Venus' atmosphere at solar minimum.

    PubMed

    Zhang, T L; Delva, M; Baumjohann, W; Auster, H-U; Carr, C; Russell, C T; Barabash, S; Balikhin, M; Kudela, K; Berghofer, G; Biernat, H K; Lammer, H; Lichtenegger, H; Magnes, W; Nakamura, R; Schwingenschuh, K; Volwerk, M; Vörös, Z; Zambelli, W; Fornacon, K-H; Glassmeier, K-H; Richter, I; Balogh, A; Schwarzl, H; Pope, S A; Shi, J K; Wang, C; Motschmann, U; Lebreton, J-P

    2007-11-29

    Venus has no significant internal magnetic field, which allows the solar wind to interact directly with its atmosphere. A field is induced in this interaction, which partially shields the atmosphere, but we have no knowledge of how effective that shield is at solar minimum. (Our current knowledge of the solar wind interaction with Venus is derived from measurements at solar maximum.) The bow shock is close to the planet, meaning that it is possible that some solar wind could be absorbed by the atmosphere and contribute to the evolution of the atmosphere. Here we report magnetic field measurements from the Venus Express spacecraft in the plasma environment surrounding Venus. The bow shock under low solar activity conditions seems to be in the position that would be expected from a complete deflection by a magnetized ionosphere. Therefore little solar wind enters the Venus ionosphere even at solar minimum.

  4. Solar Wind Ablation of Terrestrial Planet Atmospheres

    NASA Technical Reports Server (NTRS)

    Moore, Thomas Earle; Fok, Mei-Ching H.; Delcourt, Dominique C.

    2009-01-01

    Internal plasma sources usually arise in planetary magnetospheres as a product of stellar ablation processes. With the ignition of a new star and the onset of its ultraviolet and stellar wind emissions, much of the volatiles in the stellar system undergo a phase transition from gas to plasma. Condensation and accretion into a disk is replaced by radiation and stellar wind ablation of volatile materials from the system- Planets or smaller bodies that harbor intrinsic magnetic fields develop an apparent shield against direct stellar wind impact, but UV radiation still ionizes their gas phases, and the resulting internal plasmas serve to conduct currents to and from the central body along reconnected magnetic field linkages. Photoionization and thermalization of electrons warms the ionospheric topside, enhancing Jeans' escape of super-thermal particles, with ambipolar diffusion and acceleration. Moreover, observations and simulations of auroral processes at Earth indicate that solar wind energy dissipation is concentrated by the geomagnetic field by a factor of 10-100, enhancing heavy species plasma and gas escape from gravity, and providing more current carrying capacity. Thus internal plasmas enable coupling with the plasma, neutral gas and by extension, the entire body. The stellar wind is locally loaded and slowed to develop the required power. The internal source plasma is accelerated and heated, inflating the magnetosphere as it seeks escape, and is ultimately blown away in the stellar wind. Bodies with little sensible atmosphere may still produce an exosphere of sputtered matter when exposed to direct solar wind impact. Bodies with a magnetosphere and internal sources of plasma interact more strongly with the stellar wind owing to the magnetic linkage between the two created by reconnection.

  5. Numerical study of MHD wave propagation in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Sieyra, M. V.; Schneiter, E. M.; Costa, A.; Esquivel, A.

    2017-07-01

    We present a 2D MHD simulation of wave propagation across the solar atmosphere considering the photosphere-chromosphere temperature and density stratification. The system is forced by typical p-mode perturbations. We reproduce observational results from SDO AIA.

  6. Solar control of the upper atmosphere of Triton

    NASA Technical Reports Server (NTRS)

    Lyons, James R.; Yung, Yuk L.; Allen, Mark

    1992-01-01

    If the upper atmosphere and ionosphere of Triton are controlled by precipitation of electrons from Neptune's magnetosphere as previously proposed, Triton could have the only ionosphere in the solar system not controlled by solar radiation. However, a new model of Triton's atmosphere, in which only solar radiation is present, predicts a large column of carbon atoms. With an assumed, but reasonable, rate of charge transfer between N2(+) and C, a peak C(+) abundance results that is close to the peak electron densities measured by Voyager in Triton's ionosphere. These results suggest that Triton's upper atmospheric chemistry may thus be solar-controlled. Measurement of key reaction rate constants, currently unknown or highly uncertain at Triton's low temperatures, would help to clarify the chemical and physical processes occurring in Triton's atmosphere.

  7. The Heating of the Solar Atmosphere: from the Bottom Up?

    NASA Technical Reports Server (NTRS)

    Winebarger, Amy

    2014-01-01

    The heating of the solar atmosphere remains a mystery. Over the past several decades, scientists have examined the observational properties of structures in the solar atmosphere, notably their temperature, density, lifetime, and geometry, to determine the location, frequency, and duration of heating. In this talk, I will review these observational results, focusing on the wealth of information stored in the light curve of structures in different spectral lines or channels available in the Solar Dynamic Observatory's Atmospheric Imaging Assembly, Hinode's X-ray Telescope and Extreme-ultraviolet Imaging Spectrometer, and the Interface Region Imaging Spectrograph. I will discuss some recent results from combined data sets that support the heating of the solar atmosphere may be dominated by low, near-constant heating events.

  8. Atmosphere, Ocean, Land, and Solar Irradiance Data Sets

    NASA Technical Reports Server (NTRS)

    Johnson, James; Ahmad, Suraiya

    2003-01-01

    The report present the atmosphere, ocean color, land and solar irradiation data sets. The data presented: total ozone, aerosol, cloud optical and physical parameters, temperature and humidity profiles, radiances, rain fall, drop size distribution.

  9. Basic Modeling of the Solar Atmosphere and Spectrum

    NASA Technical Reports Server (NTRS)

    Avrett, Eugene H.; Wagner, William J. (Technical Monitor)

    2000-01-01

    During the last three years we have continued the development of extensive computer programs for constructing realistic models of the solar atmosphere and for calculating detailed spectra to use in the interpretation of solar observations. This research involves two major interrelated efforts: work by Avrett and Loeser on the Pandora computer program for optically thick non-LTE modeling of the solar atmosphere including a wide range of physical processes, and work by Kurucz on the detailed high-resolution synthesis of the solar spectrum using data for over 58 million atomic and molecular lines. Our objective is to construct atmospheric models from which the calculated spectra agree as well as possible with high-and low-resolution observations over a wide wavelength range. Such modeling leads to an improved understanding of the physical processes responsible for the structure and behavior of the atmosphere.

  10. The atmospheric implications of radiation belt remediation

    NASA Astrophysics Data System (ADS)

    Rodger, C. J.; Clilverd, M. A.; Ulich, Th.; Verronen, P. T.; Turunen, E.; Thomson, N. R.

    2006-08-01

    High altitude nuclear explosions (HANEs) and geomagnetic storms can produce large scale injections of relativistic particles into the inner radiation belts. It is recognised that these large increases in >1 MeV trapped electron fluxes can shorten the operational lifetime of low Earth orbiting satellites, threatening a large, valuable population. Therefore, studies are being undertaken to bring about practical human control of the radiation belts, termed "Radiation Belt Remediation" (RBR). Here we consider the upper atmospheric consequences of an RBR system operating over either 1 or 10 days. The RBR-forced neutral chemistry changes, leading to NOx enhancements and Ox depletions, are significant during the timescale of the precipitation but are generally not long-lasting. The magnitudes, time-scales, and altitudes of these changes are no more significant than those observed during large solar proton events. In contrast, RBR-operation will lead to unusually intense HF blackouts for about the first half of the operation time, producing large scale disruptions to radio communication and navigation systems. While the neutral atmosphere changes are not particularly important, HF disruptions could be an important area for policy makers to consider, particularly for the remediation of natural injections.

  11. Possible relationships between solar activity and atmospheric constituents

    NASA Technical Reports Server (NTRS)

    Roosen, R. G.; Angione, R. J.

    1974-01-01

    The large body of data on solar variations and atmospheric constituents collected between 1902 and 1953 by the Astrophysical Observatory of the Smithsonian Institution (APO) is examined. Short term variations in amounts of atmospheric aerosols and water vapor due to seasonal changes, volcanic activity, air pollution, and frontal activity are discussed. Preliminary evidence indicates that increased solar activity is at times associated with a decrease in attenuation due to airborne particulates.

  12. Possible relationships between solar activity and atmospheric constituents

    NASA Technical Reports Server (NTRS)

    Roosen, R. G.; Angione, R. J.

    1975-01-01

    The large body of data on solar variations and atmospheric constituents collected between 1902 and 1953 by the Astrophysical Observatory of the Smithsonian Institution (APO) was examined. Short-term variations in amounts of atmospheric aerosols and water vapor due to seasonal changes, volcanic activity, air pollution, and frontal activity are discussed. Preliminary evidence indicates that increased solar activity is at times associated with a decrease in attenuation due to airborne particulates.

  13. Magnetic helicity distribution in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Yang, Shangbin; Büchner, Jörg; Zhang, Hongqi

    We have developed a method to derive the relative magnetic helicity in the solar corona based on the magnetic helicity flux at the solar photosphere. We apply the method to the two newly emerging active regions (ARs) with simple and complex magnetic structures respectively. It is found that the helicity change rate in the solar corona is consistent with the helicity flux at the solar photosphere. However, the accumulated magnetic helicity in the solar corona for the simple one reverse sign as time changed. For the complex one, there is a continuous magnetic helicity accumulated just before the occurrence of solar storm, which may reflect the formation of the magnetic flux rope. It is also found that 90% of magnetic helicity is accumulated in less than 1.1 solar radius both for the two ARs After discussing the different sources of magnetic helicity, we suggested that the long term of differential rotations could play an important role to the accumulation of magnetic helicity in the solar corona and the interplanetary space, together with strong magnetic flux emergency at the solar photosphere.

  14. Solar activity influences on atmospheric electricity and on some structures in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Reiter, Reinhold

    1989-01-01

    Only processes in the troposphere and the lower stratosphere are reviewed. General aspects of global atmospheric electricity are summarized in Chapter 3 of NCR (1986); Volland (1984) has outlined the overall problems of atmospheric electrodynamics; and Roble and Hays (1982) published a summary of solar effects on the global circuit. The solar variability and its atmospheric effects (overview by Donelly et al, 1987) and the solar-planetary relationships (survey by James et al. 1983) are so extremely complex that only particular results and selected papers of direct relevance or historical importance are compiled herein.

  15. Solar wind, radiation belt electrons and atmospheric vorticity

    NASA Astrophysics Data System (ADS)

    Mironova, Irina; Tinsley, Brian; Zhou, Limin

    The association of atmospheric vorticity changes with solar wind sector structure explored by John Wilcox and Walter Orr Roberts in the 1970s is examined in terms of the sector related minima in solar wind speed, and associated minima in relativistic electron precipitation from the outer radiation belt. Stronger correlations of atmospheric vorticity with the relativistic electron flux are found than with either solar wind speed or the passage of magnetic sector boundaries over the Earth. This is consistent with changes in the ionosphere-earth current density affecting cloud microphysics, with the ionization from the Bremsstrahlung X-rays from the relativistic electron precipitation increasing the conductivity of the stratosphere.

  16. Physical mechanisms of solar activity effects in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Ebel, A.

    1989-01-01

    A great variety of physical mechanisms of possibly solar induced variations in the middle atmosphere has been discussed in the literature during the last decades. The views which have been put forward are often controversial in their physical consequences. The reason may be the complexity and non-linearity of the atmospheric response to comparatively weak forcing resulting from solar activity. Therefore this review focuses on aspects which seem to indicate nonlinear processes in the development of solar induced variations. Results from observations and numerical simulations are discussed.

  17. Solar-wind tritium limit and nuclear processes in the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Fireman, E. L.; Damico, J.; Defelice, J.

    1975-01-01

    Tritium in Surveyor 3 material is measured, and the resulting H-3/H-1 ratio for the solar wind is applied in a solar flare-solar wind relation to investigate the mixing requirements for the solar atmosphere. The flare-wind relation is derived. None of the tritium can be attributed to solar-wind implantation. The upper limit for the H-3/He ratio in the solar wind is 4 times 10 to the minus tenth power and corresponds to a H-3/H-1 limit of 2 times 10 to the minus eleventh power. This limit imposes a requirement on the mixing rate in the solar atmosphere if the H-3 production rate in solar-surface nuclear reactions is greater than 160/sq cm per sec.

  18. Solar Variability, Lunar Spectroscopy and Earth's Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Judge, Philip G.

    Solar EUV radiation and its variability is of central importance to the earths upper atmosphere. Variability of the earths upper atmosphere is a major concern to NASAs satellite missions. This LARGE PROJECT (2 year) proposal asks for continued measurments of solar EUV variability using EUVE to observe solar light scattered from the moon. Existing EUVE data prove that we can enhance ourunderstanding of the physics of the upper atmosphere at a time when solar EUV measurements are scarce. Our aims include: (i) to understand the phase and polarization dependence of solar light scattered from the moon, (ii) to quantify variations in solar EUV irradiance, (iii) to calibrate these data with a rocket--launched EUV payload, and (iv) to use these data with simultaneous UV measurements from UARS as inputs to upper atmospheric models. Very short exposures (<30 min) are required. We request TYPE 2 observations twice a lunar month, and a variety of TYPE 1 observations to permit us to take the necessary steps towards converting lunar intensity data to absolute solar irradiances.

  19. Life of the Earth in the solar atmosphere (multimedia manual)

    NASA Astrophysics Data System (ADS)

    Kononovich, E. V.; Smirnova, O. B.; Matveychuk, T. V.; Jakunina, G. V.; Krasotkin, S. A.

    2006-08-01

    The purpose of this manual is to illustrate the major physical processes occurring in the Sun - Earth system and ecology of the planet life. The material includes three individual parts: "The Earth", "The Sun" and "The solar-terrestrial connections". Sections do not require cross-references since each of them is self-complete. Inside the sections the material is located in sequences based on the principle: from simple to complex. The material is designed for students of the senior classes of high school and junior university level interested by the problem. The section "The Earth" is devoted to the description of the basic characteristics of the planet: internal structure, magnetic field, lithosphere and an atmosphere together with various occurring in them tectonic, hydro- and atmospheric processes. The top layers of an atmosphere, an ionosphere, a zone of polar lights, radiating belts, magnetosphere are also considered. The section "The Sun" includes the following subsections: the Sun as a star, internal structure of the Sun, Solar atmosphere, solar activity, cyclicity of the solar activity, helioseismology. In the section "The solar-terrestrial connections" the previous material is used to present the influence of the active solar processes on the most various aspects of a terrestrial life: ecological, biological, mental, social, economic and so forth. The problem of forecasting of the solar activity as the key parameter determining a condition of the so-called space weather is considered.

  20. Mass dragged from Mars's atmosphere by the solar wind

    NASA Astrophysics Data System (ADS)

    Durand-Manterola, H. J.

    2003-12-01

    In the past Mars had a denser atmosphere, but it lacks a magnetic field to protect the ionosphere and exosphere from the solar wind. A model describing the loss of atmosphere by the erosion of the solar wind in geologic time is presented. Recent results shows that the Martian dynamo existed in Early and Middle Noachian. Then solar wind erosion would have started at the end of Middle Noachian or the beginning of Late Noachian. With this assumption the amount of volatiles dragged by the solar wind, if the chronology developed by Neukum and Wise is correct, is in the range of 0.472 to 1.89 Terrestrial Atmospheric Masses (TAM). If the chronology developed by Hartmann et al. is correct, the loss remains in the range of 0.0624 to 0.25 TAM.

  1. Solar Atmospheric Magnetic Energy Coupling: Radiative Redistribution Efficiency

    NASA Astrophysics Data System (ADS)

    Orange, N. Brice; Gendre, Bruce; Morris, David C.; Chesny, David

    2016-07-01

    Essential to many outstanding solar and stellar physics problems is elucidating the dynamic magnetic to radiative energy coupling of their atmospheres. Using three years of Solar Dynamics Observatory's Atmospheric Imaging Assembly and Heliosemic Magnetic Imager data of gross atmospheric feature classes, an investigation of magnetic and radiative energy redistribution is detailed. Self-consistent radiative to temperature distributions, that include magnetic weighting, of each feature class is revealed via utilizing the upper limit of thermodynamic atmospheric conditions provided by Active Region Cores (ARCs). Distinctly interesting is that our radiative energy distributions, though indicative to a linearly coupling with temperature, highlight the manifestation of diffuse ``unorganized" emission at upper transition region -- lower coronal regimes. Results we emphasize as correlating remarkably with emerging evidence for similar dependencies of magnetic energy redistribution efficiency with temperature, i.e., linearly with an embedded diffuse emitting region. We present evidence that our magnetic and radiative energy coupling descriptions are consistent with established universal scaling laws for large solar atmospheric temperature gradients and descriptions to the unresolved emission, as well as their insight to a potential origin of large variability in their previous reports. Finally, our work casts new light on the utility of narrowband observations as ad hoc tools for detailing solar atmospheric thermodynamic profiles, thus, presenting significant provisions to the field of solar and stellar physics, i.e., nature of coronae heating.

  2. Solar Radiation Estimated Through Mesoscale Atmospheric Modeling over Northeast Brazil

    NASA Astrophysics Data System (ADS)

    de Menezes Neto, Otacilio Leandro; Costa, Alexandre Araújo; Ramalho, Fernando Pinto; de Maria, Paulo Henrique Santiago

    2009-03-01

    The use of renewable energy sources, like solar, wind and biomass is rapidly increasing in recent years, with solar radiation as a particularly abundant energy source over Northeast Brazil. A proper quantitative knowledge of the incoming solar radiation is of great importance for energy planning in Brazil, serving as basis for developing future projects of photovoltaic power plants and solar energy exploitation. This work presents a methodology for mapping the incoming solar radiation at ground level for Northeast Brazil, using a mesoscale atmospheric model (Regional Atmospheric Modeling System—RAMS), calibrated and validated using data from the network of automatic surface stations from the State Foundation for Meteorology and Water Resources from Ceará (Fundação Cearense de Meteorologia e Recursos Hídricos- FUNCEME). The results showed that the model exhibits systematic errors, overestimating surface radiation, but that, after the proper statistical corrections, using a relationship between the model-predicted cloud fraction, the ground-level observed solar radiation and the incoming solar radiation estimated at the top of the atmosphere, a correlation of 0.92 with a confidence interval of 13.5 W/m2 is found for monthly data. Using this methodology, we found an estimate for annual average incoming solar radiation over Ceará of 215 W/m2 (maximum in October: 260 W/m2).

  3. Role of solar influences on geomagnetosphere and upper atmosphere

    NASA Astrophysics Data System (ADS)

    Kumar Tripathi, Arvind

    The Earth's magnetosphere and upper atmosphere can be greatly perturbed by variations in the solar luminosity caused by disturbances on the solar surface. The state of near-Earth space environment is governed by the Sun and is very dynamic on all spatial and temporal scale. The geomagnetic field which protects the Earth from solar wind and cosmic rays is also essential to the evolution of life; its variations can have either direct or indirect effect on human physiology and health state even if the magnitude of the disturbance is small. Geomagnetic disturbances are seen at the surface of the Earth as perturbations in the components of the geomagnetic field, caused by electric currents flowing in the magnetosphere and upper atmosphere. Ionospheric and thermospheric storms also result from the redistribution of particles and fields. Global thermospheric storm winds and composition changes are driven by energy injection at high latitudes. These storm effects may penetrate downwards to the lower thermosphere and may even perturb the mesosphere. Many of the ionospheric changes at mid-latitude can be understood as a response to thermospheric perturbations. The transient bursts of solar energetic particles, often associated with large solar transients, have been observed to have effects on the Earth's middle and lower atmosphere, including the large-scale destruction of polar stratospheric and tropospheric ozone. In the present, we have discussed effect of solar influences on earth's magnetosphere and upper atmosphere that are useful to space weather and global warming, on the basis of various latest studies.

  4. Solar wind interaction with Venus and impact on its atmosphere

    NASA Astrophysics Data System (ADS)

    Barabash, S.; Futaana, Y.; Wieser, G. S.; Luhmann, J.

    2014-04-01

    We present a review of the solar wind interaction with Venus and how the interaction affects the Venusian atmosphere. The Venus Express observations for more than 8 years (2005-present) and quantitatively new simulation codes substantially advanced physical understanding of the plasma processes in the near-Venus space since the Pioneer Venus Orbiter (PVO) mission (1978-1992). The near-Venus space can be divided into several plasma domains: the magnetotail with the plasmasheet, induced magnetosphere, and magnetosheath. The bow shock separates the undisturbed solar wind from the Venus-affected environment. We review the shapes and positions of the boundaries enveloping the main domains and discuss how they are formed by the current systems and pressure balance. In particular, we discuss the morphology and dynamics of the near-Venus magnetotail that was not accessible by PVO. Using the unique Venus Express measurements we discuss the ion acceleration processes and their links to the ionosphere. The focus is given to the Venus' atmosphere erosion associated with the solar wind interaction, both through the energy (ion acceleration) and momentum (atmospheric sputtering) transfer. We review the measurements of the escape rates, their variability with the upstream solar wind conditions and the solar cycle. We emphasize the measurements duirng extreme solar wind conditions as an analogue with nominal conditions for the young Sun. The modeling efforts in this area are also reviewed as they provide a quantitatively approach to understand the impact of the solar wind interaction on the atmospheric evolution. Finally, we compare Venus with other planets of the terrestrial planet group, the Earth and Mars. The Earth, a twin planet of the similar size, is magnetized. Mars, an unmagnetized planet like Venus, possesses by far weaker gravitation to hold its atmospheric gasses. This comparative magnetosphere approach based on the natural solar system laboratory of experiments gives

  5. Report of the Solar and Atmospheric Neutrino Working Group

    SciTech Connect

    Back, H.; Bahcall, J.N.; Bernabeu, J.; Boulay, M.G.; Bowles, T.; Calaprice, F.; Champagne, A.; Freedman, S.; Gai, M.; Galbiati, C.; Gallagher, H.; Gonzalez-Garcia, C.; Hahn, R.L.; Heeger, K.M.; Hime, A.; Jung, C.K.; Klein, J.R.; Koike, M.; Lanou, R.; Learned, J.G.; Lesko, K.T.; Losecco, J.; Maltoni, M.; Mann, A.; McKinsey, D.; Palomares-Ruiz, S.; Pena-Garay, C.; Petcov, S.T.; Piepke, A.; Pitt, M.; Raghavan, R.; Robertson, R.G.H.; Scholberg, K.; Sobel, H.W.; Takeuchi, T.; Vogelaar, R.; Wolfenstein, L.

    2004-10-22

    The highest priority of the Solar and Atmospheric Neutrino Experiment Working Group is the development of a real-time, precision experiment that measures the pp solar neutrino flux. A measurement of the pp solar neutrino flux, in comparison with the existing precision measurements of the high energy {sup 8}B neutrino flux, will demonstrate the transition between vacuum and matter-dominated oscillations, thereby quantitatively testing a fundamental prediction of the standard scenario of neutrino flavor transformation. The initial solar neutrino beam is pure {nu}{sub e}, which also permits sensitive tests for sterile neutrinos. The pp experiment will also permit a significantly improved determination of {theta}{sub 12} and, together with other solar neutrino measurements, either a measurement of {theta}{sub 13} or a constraint a factor of two lower than existing bounds. In combination with the essential pre-requisite experiments that will measure the {sup 7}Be solar neutrino flux with a precision of 5%, a measurement of the pp solar neutrino flux will constitute a sensitive test for non-standard energy generation mechanisms within the Sun. The Standard Solar Model predicts that the pp and {sup 7}Be neutrinos together constitute more than 98% of the solar neutrino flux. The comparison of the solar luminosity measured via neutrinos to that measured via photons will test for any unknown energy generation mechanisms within the nearest star. A precise measurement of the pp neutrino flux (predicted to be 92% of the total flux) will also test stringently the theory of stellar evolution since the Standard Solar Model predicts the pp flux with a theoretical uncertainty of 1%. We also find that an atmospheric neutrino experiment capable of resolving the mass hierarchy is a high priority. Atmospheric neutrino experiments may be the only alternative to very long baseline accelerator experiments as a way of resolving this fundamental question. Such an experiment could be a very

  6. Variability of solar/stellar activity and magnetic field and its influence on planetary atmosphere evolution

    NASA Astrophysics Data System (ADS)

    Lammer, Helmut; Güdel, Manuel; Kulikov, Yuri; Ribas, Ignasi; Zaqarashvili, Teimuraz V.; Khodachenko, Maxim L.; Kislyakova, Kristina G.; Gröller, Hannes; Odert, Petra; Leitzinger, Martin; Fichtinger, Bibiana; Krauss, Sandro; Hausleitner, Walter; Holmström, Mats; Sanz-Forcada, Jorge; Lichtenegger, Herbert I. M.; Hanslmeier, Arnold; Shematovich, Valery I.; Bisikalo, Dmitry; Rauer, Heike; Fridlund, Malcolm

    2012-02-01

    It is shown that the evolution of planetary atmospheres can only be understood if one recognizes the fact that the radiation and particle environment of the Sun or a planet's host star were not always on the same level as at present. New insights and the latest observations and research regarding the evolution of the solar radiation, plasma environment and solar/stellar magnetic field derived from the observations of solar proxies with different ages will be given. We show that the extreme radiation and plasma environments of the young Sun/stars have important implications for the evolution of planetary atmospheres and may be responsible for the fact that planets with low gravity like early Mars most likely never build up a dense atmosphere during the first few 100 Myr after their origin. Finally we present an innovative new idea on how hydrogen clouds and energetic neutral atom (ENA) observations around transiting Earth-like exoplanets by space observatories such as the WSO-UV, can be used for validating the addressed atmospheric evolution studies. Such observations would enhance our understanding on the impact on the activity of the young Sun on the early atmospheres of Venus, Earth, Mars and other Solar System bodies as well as exoplanets.

  7. A new instrument for sounding the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Cacciani, A.; Jefferies, S. M.; Finsterle, W.; Rapex, P.; Knox, A.; Giebink, C.; di Martino, V.

    2003-02-01

    A new instrument based on Magneto-Optical Filters (MOFs) (Cacciani et al., 1994) will be used to simultaneously map the line-of-sight velocity at two heights in the solar atmosphere. Simultaneous Doppler images of 5 arc-seconds resolution will be taken in the K I (7699 Å) and Na I D2 (5890 Å) lines, which are separated by a few hundred kilometers in the solar atmosphere (Grossman-Doerth, 1994). By cross correlating the signals of the K and Na channels we will be able to determine the travel time and thus the propagation speed of sound waves in the solar atmosphere. The experiment will be run at the South Pole during austral summer of 2002/2003.

  8. Solar-wind interactions - Nature and composition of lunar atmosphere

    NASA Technical Reports Server (NTRS)

    Mukherjee, N. R.

    1975-01-01

    The nature and composition of the lunar atmosphere are examined on the basis of solar-wind interactions, and the nature of the species in the trapped-gas layer is discussed using results of theoretical and experimental investigations. It is shown that the moon has a highly tenuous atmosphere consisting of various species derived from five sources: solar-wind interaction products, cosmic-ray interaction products, effects of meteoritic impacts, planetary degassing, and radioactive-decay products. Atmospheric concentrations are determined for those species derived from solar-wind protons, alpha particles, and oxygen ions. Carbon chemistry is briefly discussed, and difficulties encountered in attempts to determine quantitatively the concentrations of molecular oxygen, atomic oxygen, carbon monoxide, carbon dioxide, and methane are noted. The calculated concentrations are shown to be in good agreement with observations by the Apollo 17 lunar-surface mass spectrometer and orbital UV spectrometer.

  9. Ions in the Terrestrial Atmosphere and Other Solar System Atmospheres

    NASA Astrophysics Data System (ADS)

    Harrison, R. Giles; Tammet, Hannes

    2008-06-01

    Charged molecular clusters, traditionally called small ions, carry electric currents in atmospheres. Charged airborne particles, or aerosol ions, play an important role in generation and evolution of atmospheric aerosols. Growth of ions depends on the trace gas content, which is highly variable in the time and space. Even at sub-ppb concentrations, electrically active organic compounds ( e.g. pyridine derivatives) can affect the ion composition and size. The size and mobility are closely related, although the form of the relationship varies depending on the critical diameter, which, at 273 K, is about 1.6 nm. For ions smaller than this the separation of quantum levels exceeds the average thermal energy, allowing use of a molecular aggregate model for the size-mobility relation. For larger ions the size-mobility relation approaches the Stokes-Cunningham-Millikan law. The lifetime of a cluster ion in the terrestrial lower atmosphere is about one minute, determined by the balance between ion production rate, ion-ion recombination, and ion-aerosol attachment.

  10. Ions in the Terrestrial Atmosphere and Other Solar System Atmospheres

    NASA Astrophysics Data System (ADS)

    Harrison, R. Giles; Tammet, Hannes

    Charged molecular clusters, traditionally called small ions, carry electric currents in atmospheres. Charged airborne particles, or aerosol ions, play an important role in generation and evolution of atmospheric aerosols. Growth of ions depends on the trace gas content, which is highly variable in the time and space. Even at sub-ppb concentrations, electrically active organic compounds (e.g. pyridine derivatives) can affect the ion composition and size. The size and mobility are closely related, although the form of the relationship varies depending on the critical diameter, which, at 273 K, is about 1.6 nm. For ions smaller than this the separation of quantum levels exceeds the average thermal energy, allowing use of a molecular aggregate model for the size-mobility relation. For larger ions the size-mobility relation approaches the Stokes-Cunningham-Millikan law. The lifetime of a cluster ion in the terrestrial lower atmosphere is about one minute, determined by the balance between ion production rate, ion-ion recombination, and ion-aerosol attachment.

  11. Diagnosing transient plasma status: from solar atmosphere to tokamak divertor

    NASA Astrophysics Data System (ADS)

    Giunta, A. S.; Henderson, S.; O'Mullane, M.; Harrison, J.; Doyle, J. G.; Summers, H. P.

    2016-09-01

    This work strongly exploits the interdisciplinary links between astrophysical (such as the solar upper atmosphere) and laboratory plasmas (such as tokamak devices) by sharing the development of a common modelling for time-dependent ionisation. This is applied to the interpretation of solar flare data observed by the UVSP (Ultraviolet Spectrometer and Polarimeter), on-board the Solar Maximum Mission and the IRIS (Interface Region Imaging Spectrograph), and also to data from B2-SOLPS (Scrape Off Layer Plasma Simulations) for MAST (Mega Ampère Spherical Tokamak) Super-X divertor upgrade. The derived atomic data, calculated in the framework of the ADAS (Atomic Data and Analysis Structure) project, allow equivalent prediction in non-stationary transport regimes and transients of both the solar atmosphere and tokamak divertors, except that the tokamak evolution is about one thousand times faster.

  12. SOHO: An observatory to study the solar interior and the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Domingo, V.; Poland, A. I.

    1988-01-01

    The Solar and Heliospheric Observatory (SOHO) is described. The two main objectives of SOHO are to improve understanding of solar coronal phenomena and to study solar structure and interior dynamics from its core to the photosphere. The primary goals of the coronal and solar wind studies are to understand the coronal heating mechanism and its expansion into the solar wind. These goals will be achieved both by remote sensing of the solar atmosphere with high resolution spectrometers and telescopes and by in situ measurement of the composition and energy of the resulting solar wind and the energetic particles that propagate through it. The structure and interior dynamics are to be studied by helioseismological methods and the measurement of solar irradiance variations. The SOHO spacecraft will be three-axis stabilized and located in a halo orbit around the L1 Lagrangian point (approximately 1 percent of the distance from the Earth to the Sun). It is currently scheduled for launch in July 1995.

  13. The radiation in the atmosphere during major solar particle events

    NASA Astrophysics Data System (ADS)

    Clucas, S.; Dyer, C.; Lei, F.

    Major solar particle events can give rise to greatly enhanced radiation throughout the entire atmosphere including at aircraft altitudes. These particle events are very hard to predict and their effect on aircraft is difficult to calculate. A comprehensive model of the energetic radiation in the atmosphere has been developed based on a response matrix of the atmosphere to energetic particle incidence. This model has previously been used to determine the spectral form of several ground level neutron events including February 56 and September/October 1989. Significant validation of the model has been possible using CREAM data flying onboard Concorde during the September/October 1989 events. Further work has been carried out for this solar maximum, including estimates of the solar particle spectra during the July 2000, April 2001, and October 2003 events and comparisons of predicated atmospheric measurements with limited flight data. Further CREAM data has being obtained onboard commercial airlines and high altitude business jets during quiet time periods. In addition, the atmospheric radiation model, along with solar particle spectra, have been used to calculate the neutron flux and dose rates along several commercial aircraft flight paths including London - LA. The influence of suppression on cut-off rigidity by geomagnetic storms is examined and shows that the received flight dose during disturbed periods can be significantly enhanced compared with quiet periods.

  14. The radiation in the atmosphere during major solar particle events

    NASA Astrophysics Data System (ADS)

    Clucas, Simon N.; Dyer, Clive S.; Lei, Fan

    Major solar particle events can give rise to greatly enhanced radiation throughout the entire atmosphere including at aircraft altitudes. These particle events are very hard to predict and their effect on aircraft is difficult to calculate. A comprehensive model of the energetic radiation in the atmosphere has been developed based on a response matrix of the atmosphere to energetic particle incidence. This model has previously been used to determine the spectral form of several ground level neutron events including February 1956 and September/October 1989. Significant validation of the model has been possible using CREAM data flying onboard Concorde during the September/October 1989 events. Further work has been carried out for the current solar maximum, including estimates of the solar particle spectra during the July 2000, April 2001, and October 2003 events and comparisons of predicted atmospheric measurements with limited flight data. Further CREAM data have been obtained onboard commercial airlines and high altitude business jets during quiet time periods. In addition, the atmospheric radiation model, along with solar particle spectra, have been used to calculate the neutron flux and dose rates along several commercial aircraft flight paths including London to Los Angeles. The influence of rigidity cut-off suppression by geomagnetic storms is examined and shows that the received flight dose during disturbed periods can be significantly enhanced compared with quiet periods.

  15. Magnetic field line braiding in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Candelaresi, S.; Pontin, D. I.; Hornig, G.

    2017-10-01

    Using a magnetic carpet as model for the near surface solar magnetic field we study its effects on the propagation of energy injectected by photospheric footpoint motions. Such a magnetic carpet structure is topologically highly non-trivial and with its magnetic nulls exhibits qualitatively different behavior than simpler magnetic fields. We show that the presence of magnetic fields connecting back to the photosphere inhibits the propagation of energy into higher layers of the solar atmosphere, like the solar corona. By applying certain types of footpoint motions the magnetic field topology is is greatly reduced through magnetic field reconnection which facilitates the propagation of energy and disturbances from the photosphere.

  16. Solar atmospheric neutrinos and the sensitivity floor for solar dark matter annihilation searches

    NASA Astrophysics Data System (ADS)

    Argüelles, C. A.; de Wasseige, G.; Fedynitch, A.; Jones, B. J. P.

    2017-07-01

    Cosmic rays interacting in the solar atmosphere produce showers that result in a flux of high-energy neutrinos from the Sun. These form an irreducible background to indirect solar WIMP self-annihilation searches, which look for heavy dark matter particles annihilating into final states containing neutrinos in the Solar core. This background will eventually create a sensitivity floor for indirect WIMP self-annihilation searches analogous to that imposed by low-energy solar neutrino interactions for direct dark matter detection experiments. We present a new calculation of the flux of solar atmospheric neutrinos with a detailed treatment of systematic uncertainties inherent in solar atmospheric shower evolution, and we use this to derive the sensitivity floor for indirect solar WIMP annihilation analyses. We find that the floor lies less than one order of magnitude beyond the present experimental limits on spin-dependent WIMP-proton cross sections for some mass points, and that the high-energy solar atmospheric neutrino flux may be observable with running and future neutrino telescopes.

  17. Penetration of solar irradiances through the atmosphere and plant canopies.

    NASA Technical Reports Server (NTRS)

    Weinman, J. A.; Guetter, P. J.

    1972-01-01

    The equation of radiative transfer is applied to an analysis of solar irradiances penetrating into a plant canopy covered by a turbid atmosphere. The method of discrete coordinates is applied to vertically inhomogeneous atmospheres and plant canopies. It is shown that four-point quadrature yields results with an accuracy that is consistent with irradiance measurements. It is believed that the presented computational scheme may have considerable agricultural applications.

  18. Solar wind influences on atmospheric electricity variables in polar regions

    NASA Astrophysics Data System (ADS)

    Michnowski, Stanisław

    The measurement techniques applied in magnetospheric and ionospheric research enable detection of strong, intrinsic effects of solar wind on ionospheric electrical potential distribution and conductivity of the atmosphere. These manifestations of the solar wind interaction with the magnetosphere and ionosphere are especially evident at high latitudes. The possibility of observing there the response of the atmospheric electricity variables to solar wind has been questioned for a long time despite the fact that the atmospheric electric field and current variations at the ground are physically linked with electric potential of the ionosphere and conductivity of the lower atmosphere. The serious doubts were mainly due to the generally accepted opinion that the highly conducting ionosphere is an almost ideal equipotential electric screen that separates the weakly conductive lower atmosphere of the influence from space. This assumption could not be further upheld in view of the new findings. They have been provided for some time by ground-based atmospheric electric field and current measurements (AEMs) with simultaneous upper atmosphere observations and by corresponding balloon measurements. Recent ground-based AEMs in polar regions, i.e., in the near-subauroral, auroral, and polar cap high-latitude regions, have detected considerable influence of solar wind on the lower-atmosphere electric variables. However, the use of atmospheric electric observations in studying solar-terrestrial relations is still limited. The main reason is difficulty in separating various local meteorological effects, anthropogenic effects, and the effects of the global electric current circuit which affect simultaneously the measured quantities. Transmission of the electric signals through the lower atmosphere can also introduce troublesome disturbances. The paper outlines these problems and hints how the difficulties involved might be partly overcome in a feasible way. The needs and possible

  19. Constraining neutrino oscillation parameters with current solar and atmospheric data

    NASA Astrophysics Data System (ADS)

    Maltoni, M.; Schwetz, T.; Tórtola, M. A.; Valle, J. W.

    2003-01-01

    We analyze the impact of recent solar and atmospheric data on the determination of the neutrino oscillation parameters, taking into account that both the solar νe and the atmospheric νμ may convert to a mixture of active and sterile neutrinos. We use the most recent global solar neutrino data, including the 1496-day Super-K neutrino data sample, and we investigate in detail the impact of the recent Sudbury Neutrino Observatory (SNO) neutral current, spectral, and day/night data by performing also an analysis using only the charged current rate from SNO. We confirm the clear preference of the pure active large mixing angle solution of the solar neutrino problem and obtain that the LOW solution, vacuum oscillation, small mixing angle, and just-so2 solutions are disfavored with a Δχ2=9, 9, 23, 31, respectively. Furthermore, we find that the global solar data constrains the admixture of a sterile neutrino to be less than 44% at 99% C.L. A pure sterile solution is ruled out with respect to the active one at 99.997% C.L. By performing an improved fit of the atmospheric data, we also update the corresponding regions of oscillation parameters. We find that the recent atmospheric Super-K (1489-day) and MACRO data have a strong impact on constraining a sterile component in atmospheric oscillations: if the νμ is restricted to the atmospheric mass states only a sterile admixture of 16% is allowed at 99% C.L., while a bound of 35% is obtained in the unconstrained case. Pure sterile oscillations are disfavored with a Δχ2=34.6 compared to the pure active case.

  20. A numerical calculation of outward propagation of solar disturbances. [solar atmospheric model with shock wave propagation

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    1974-01-01

    The responses of the solar atmosphere due to an outward propagation shock are examined by employing the Lax-Wendroff method to solve the set of nonlinear partial differential equations in the model of the solar atmosphere. It is found that this theoretical model can be used to explain the solar phenomena of surge and spray. A criterion to discriminate the surge and spray is established and detailed information concerning the density, velocity, and temperature distribution with respect to the height and time is presented. The complete computer program is also included.

  1. Solar EUV Spectrophotometer for Atmosphere Explorer Satellites.

    DTIC Science & Technology

    1976-08-31

    spectral scans are made for each of the 21 monochro- mators. Results are examined for alignment , vigne tt in g , sca ttered light levels , and signal...drawings. “ Sol ar EUV Spectrophotometer for Atmosphere Explorer: Equipment Information Report” , Data Item A005 , Con trac t Fl9628-72-C- Oll S , prepared by BBRC for AFCRL , Apr i l , 1 9 7 6 . 4-1 I

  2. Excitation of electron Langmuir frequency harmonics in the solar atmosphere

    SciTech Connect

    Fomichev, V. V.; Fainshtein, S. M.; Chernov, G. P.

    2013-05-15

    An alternative mechanism for the excitation of electron Langmuir frequency harmonics as a result of the development of explosive instability in a weakly relativistic beam-plasma system in the solar atmosphere is proposed. The efficiency of the new mechanism as compared to the previously discussed ones is analyzed.

  3. Waves and Oscillations in the Solar Atmosphere (IAU S247)

    NASA Astrophysics Data System (ADS)

    Erdélyi, Robert; Mendoza-Briceno, César A.

    2008-06-01

    Preface; Organizing committee; Conference participants; Address by the Scientific Organizing Committee R. Erdélyi; Progress in coronal seismology B. Roberts; Session 1. Waves and oscillations in solar and stellar interior Robert Erdélyi; Session 2. Coupling of global solar and stellar motions into the lower atmosphere Bernard Roberts; Session 3. Seismology of the lower solar atmosphere and stellar chromospheres Siraj S. Hasan; Session 4. Seismology of open versus closed magnetic structures Marcel Goossens; Session 5. Prominence seismology Jose Luis Ballester; Session 6. Dynamical processes and coupling in the magnetic atmosphere of Sun and stars Miguel Ibañez; Session 7. Wave-particle interactions in magnetized plasmas Cesar A. Mendoza-Briceño; Session 8. Solar and stellar global coronal seismology Viggo Hansteen; Session 9. Fundamental physical processes in coronae: waves, turbulence, reconnection Saku Tsuneta; Session 10. Waves and instabilities in atmospheric plasmas Arnold O. Benz; Summary of meeting Cesar A. Mendoza-Briceño; Concluding remarks A. O. Benz; Late papers; Author index.

  4. Asymmetric Magnetic Reconnection in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Murphy, N. A.; Miralles, M. P.; Ranquist, D. A.; Pope, C. L.; Raymond, J. C.; Lukin, V. S.; McKillop, S.; Shen, C.; Winter, H. D.; Reeves, K. K.; Lin, J.

    2013-12-01

    Models of solar flares and coronal mass ejections typically predict the development of an elongated current sheet in the wake behind the rising flux rope. In reality, reconnection in these current sheets will be asymmetric along the inflow, outflow, and out-of-plane directions. We perform resistive MHD simulations to investigate the consequences of asymmetry during solar reconnection. We predict several observational signatures of asymmetric reconnection, including flare loops with a skewed candle flame shape, slow drifting of the current sheet into the strong field upstream region, asymmetric footpoint speeds and hard X-ray emission, and rolling motions within the erupting flux rope. There is net plasma flow across the magnetic field null along both the inflow and outflow directions. We compare simulations to SDO/AIA, Hinode/XRT, and STEREO observations of flare loop shapes, current sheet drifting, and rolling motions during prominence eruptions. Simulations of the plasmoid instability with different upstream magnetic fields show that the reconnection rate remains enhanced even during the asymmetric case. The islands preferentially grow into the weak field upstream region. The islands develop net vorticity because the outflow jets impact them obliquely rather than directly. Asymmetric reconnection in the chromosphere occurs when emerging flux interacts with pre-existing overlying flux. We present initial results on asymmetric reconnection in partially ionized chromospheric plasmas. Finally, we discuss how comparisons to observations are necessary to understand the role of three-dimensional effects.

  5. Asymmetric Magnetic Reconnection in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Murphy, N. A.; Miralles, M. P.; Ranquist, D. A.; Pope, C. L.; Raymond, J. C.; Lukin, V. S.; McKillop, S. C.; Shen, C.; Winter, H. D.; Reeves, K. K.; Lin, J.

    2013-12-01

    Models of solar flares and coronal mass ejections typically predict the development of an elongated current sheet in the wake behind the rising flux rope. In reality, reconnection in these current sheets will be asymmetric along the inflow, outflow, and out-of-plane directions. We perform resistive MHD simulations to investigate the consequences of asymmetry during solar reconnection. We predict several observational signatures of asymmetric reconnection, including flare loops with a skewed candle flame shape, slow drifting of the current sheet into the strong field upstream region, asymmetric footpoint speeds and hard X-ray emission, and rolling motions within the erupting flux rope. There is net plasma flow across the magnetic field null along both the inflow and outflow directions. We compare simulations to SDO/AIA, Hinode/XRT, and STEREO observations of flare loop shapes, current sheet drifting, and rolling motions during prominence eruptions. Simulations of the plasm! oid instability with different upstream magnetic fields show that the reconnection rate remains enhanced even during the asymmetric case. The islands preferentially grow into the weak field upstream region. The islands develop net vorticity because the outflow jets impact them obliquely rather than directly. Asymmetric reconnection in the chromosphere occurs when emerging flux interacts with pre-existing overlying flux. We present initial results on asymmetric reconnection in partially ionized chromospheric plasmas. Finally, we discuss how comparisons to observations are necessary to understand the role of three-dimensional effects.

  6. Observational evidence for Alfven waves in the solar atmosphere (Invited)

    NASA Astrophysics Data System (ADS)

    De Pontieu, B.

    2013-12-01

    Alfven waves have long been suspected of playing an important role in both heating the corona and accelerating the solar wind. Recently, more and more observational evidence for the presence of such waves has been reported in both the corona and the lower solar atmosphere. I will review observations of the properties and presence of Alfven waves from CoMP, Hinode, AIA and ground-based telescopes in both coronal lines and the lower solar atmosphere. I will discuss our current understanding of the importance of these waves for the energy balance of the corona. I will also present initial results of the Interface Region Imaging Spectrograph (IRIS) which was launched in June 2013 and obtains images and spectra in both the far and near ultraviolet.

  7. Accelerator, reactor, solar, and atmospheric neutrino oscillations: Beyond three generations

    SciTech Connect

    Goswami, S.

    1997-03-01

    We perform a phenomenological analysis of neutrino oscillations introducing an additional sterile neutrino. In such a scenario, more than one spectrum is possible that can accommodate three hierarchically different mass-squared differences as required by the present experiments. We considered two different spectra. Choosing the {Delta}m{sup 2}s in the ranges suitable for the LSND, atmospheric, and solar neutrino oscillations, limits on the mixing angles are derived, consistent with the most restrictive accelerator and reactor data as well as the atmospheric and solar neutrino results. We show that the present data disfavor one of these mass spectra leaving us with a very stringent choice of mass and mixing angle. The potential of the future heavy water solar neutrino experiment SNO to distinguish between the four-neutrino mixing and two-neutrino mixing cases is explored. {copyright} {ital 1997} {ital The American Physical Society}

  8. The atmospheric radiation response to solar-particle-events.

    PubMed

    O'Brien, K; Sauer, H H

    2003-01-01

    High-energy solar particles, produced in association with solar flares and coronal mass ejections, occasionally bombard the earth's atmosphere. resulting in radiation intensities additional to the background cosmic radiation. Access of these particles to the earth's vicinity during times of geomagnetic disturbances are not adequately described by using static geomagnetic field models. These solar fluxes are also often distributed non uniformly in space, so that fluxes measured by satellites obtained at great distances from the earth and which sample large volumes of space around the earth cannot be used to predict fluxes locally at the earth's surface. We present here a method which uses the ground-level neutron monitor counting rates as adjoint sources of the flux in the atmosphere immediately above them to obtain solar-particle effective dose rates as a function of position over the earth's surface. We have applied this approach to the large September 29-30, 1989 ground-level event (designated GLE 42) to obtain the magnitude and distribution of the solar-particle effective dose rate from an atypically large event. The results of these calculations clearly show the effect of the softer particle spectra associated with solar particle events, as compared with galactic cosmic rays, results in a greater sensitivity to the geomagnetic field, and, unlike cosmic rays, the near-absence of a "knee" near 60 degrees geomagnetic latitude.

  9. Multi-height spectroscopy for probing the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Wiśniewska, A.; Roth, M.; Staiger, J.

    We present preliminary results from multi-height observations, taken with the HELLRIDE (HELioseismic Large Region Interferometric DEvice) instrument at the VTT (Vacuum Tower Telescope) in Izaña, Tenerife. The goal of this work is to study solar oscillations at different atmospheric heights. The data was obtained in May 2014 for 10 different wavelengths with high spatial, spectral and temporal resolution. In this paper we discuss the results from quiet sun measurements. The region was selected in such a way to be near to the disk center. Using spectral and cross-spectral analysis methods we derive phase differences of waves propagating between the atmospheric layers. The formation heights of the photospheric spectral lines were calculated by τ^c_{5000} = 1 in agreement with an LTE approximation and chromospheric lines with an NLTE method, respectively. We find that the acoustic cut-off frequency is a function of height in the solar atmosphere.

  10. Nearly sonic and transsonic convective motions in the solar atmosphere related to the solar wind origin

    NASA Technical Reports Server (NTRS)

    Veselovsky, I. S.

    1995-01-01

    MHD equations are considered for the solar atmosphere. 15 different simplest MHD regimes are indicated for the momentum transport equation depending on the mutual binary interplay between 6 possible and locally dominant terms: non-stationarity and inhomogeneity of the flow, gas pressure, magnetic tensions, viscous and gravity forces. These regimes are delimited by five physically independent dimensionless parameters, for example, Strouhal, sonic Mach, alfvenic Mach, Reynolds and Froude numbers or their combinations. Another partially overlapping classification of the simplest regimes may be introduced based on the energy conservation equation. There are also 15 independent binary combinations between nonstationary and inhomogeneous convective terms, dissipative energy sinks and sources (viscous, heat-conductive, Joule and radiative ones) in the energy equation. More complicated regimes are considered with multiple dominated terms. All these MHD regimes play their important role somewhere in the solar atmosphere complicated by the tensor transport coefficients in the magnetically dominated regions of the upper atmosphere. Nearly sonic and transsonic nonstationary convective motions with ascending and descending flows are observed in the solar chromosphere. the transition region and the lower pans of the solar corona together with related horizontal velocity components. This convection represents a kind of the 'cocoonery' manufacturing nonstationary vortices generated here and partially connected to the photosphere and to the solar wind. The solar wind originates from this powerful transsonic muddle in the solar atmosphere as a tiny fraction of the streamlines which are temporarily getting detached from the 'cocoons; and going to the infinity. The topologically complicated instantaneous 'runaway surface' around the Sun, i.e., the surface which separates outgoing to the infinity streams from other finite flows in the solar atmosphere was not described in the

  11. Is magnetic topology important for heating the solar atmosphere?

    PubMed

    Parnell, Clare E; Stevenson, Julie E H; Threlfall, James; Edwards, Sarah J

    2015-05-28

    Magnetic fields permeate the entire solar atmosphere weaving an extremely complex pattern on both local and global scales. In order to understand the nature of this tangled web of magnetic fields, its magnetic skeleton, which forms the boundaries between topologically distinct flux domains, may be determined. The magnetic skeleton consists of null points, separatrix surfaces, spines and separators. The skeleton is often used to clearly visualize key elements of the magnetic configuration, but parts of the skeleton are also locations where currents and waves may collect and dissipate. In this review, the nature of the magnetic skeleton on both global and local scales, over solar cycle time scales, is explained. The behaviour of wave pulses in the vicinity of both nulls and separators is discussed and so too is the formation of current layers and reconnection at the same features. Each of these processes leads to heating of the solar atmosphere, but collectively do they provide enough heat, spread over a wide enough area, to explain the energy losses throughout the solar atmosphere? Here, we consider this question for the three different solar regions: active regions, open-field regions and the quiet Sun. We find that the heating of active regions and open-field regions is highly unlikely to be due to reconnection or wave dissipation at topological features, but it is possible that these may play a role in the heating of the quiet Sun. In active regions, the absence of a complex topology may play an important role in allowing large energies to build up and then, subsequently, be explosively released in the form of a solar flare. Additionally, knowledge of the intricate boundaries of open-field regions (which the magnetic skeleton provides) could be very important in determining the main acceleration mechanism(s) of the solar wind. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  12. UV Spectra, Bombs, and the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Judge, Philip G.

    2015-08-01

    A recent analysis of UV data from the Interface Region Imaging Spectrograph (IRIS) reports plasma “bombs” with temperatures near 8 × 104 K within the solar photosphere. This is a curious result, first because most bomb plasma pressures p (the largest reported case exceeds 103 dyn cm-2) fall well below photospheric pressures (\\gt 7× {10}3), and second, UV radiation cannot easily escape from the photosphere. In the present paper the IRIS data is independently analyzed. I find that the bombs arise from plasma originally at pressures between ≤ 80 and 800 dyne cm-2 before explosion, i.e., between ≥ 850 and 550 km above {τ }500=1. This places the phenomenon’s origin in the low-mid chromosphere or above. I suggest that bomb spectra are more compatible with Alfvénic turbulence than with bi-directional reconnection jets.

  13. 3D model atmospheres and the solar photospheric oxygen abundance

    NASA Astrophysics Data System (ADS)

    Caffau, E.; Ludwig, H.-G.

    2008-10-01

    In recent years the photospheric solar oxygen abundance experienced a significant downward revision. However, a low photospheric abundance is incompatible with the value in the solar interior inferred from helioseismology. For contributing to the dispute whether the solar oxygen abundance is “high” or “low”, we re-derived its photospheric abundance independently of previous analyses. We applied 3D (CO5BOLD) as well as 1D model atmospheres. We considered standard disc-centre and disc-integrated spectral atlases, as well as newly acquired solar intensity spectra at different heliocentric angles. We determined the oxygen abundances from equivalent width and/or line profile fitting of a number of atomic lines. As preliminary result, we find an oxygen abundance in the range 8.73 8.79, encompassing the value obtained by Holweger (2001), and somewhat higher than the value obtained by Asplund et al. (2005).

  14. An investigation of aerosol optical properties: Atmospheric implications and influences

    NASA Astrophysics Data System (ADS)

    Penaloza-Murillo, Marcos A.

    An experimental, observational, and theoretical investigation of aerosol optical properties has been made in this work to study their implications and influences on the atmosphere. In the laboratory the scientific and instrumental methodology consisted of three parts, namely, aerosol generation, optical and mass concentration measurements, and computational calculations. In particular the optical properties of ammonium sulfate and caffeine aerosol were derived from measurements made with a transmissometer cell-reciprocal- integrating nephelometer (TCRIN), equipped with a laser beam at 632.8 nm, and by applying a Mie theory computer code The aerosol generators, optical equipment and calibration procedures were reviewed. The aerosol shape and size distribution were studied by means of scanning electron microscopy and the Gumprecht- Sliepcevich/Lipofsky-Green extinction-sedimentation method. In particular the spherical and cylindrical shape were considered. During this investigation, an alternative method for obtaining the optical properties of monodisperse spherical non-absorbing aerosol using a cell-transmissometer, which is based on a linearisation of the Lambert-Beer law, was found. In addition, adapting the TCRIN to electrooptical aerosol studies, the optical properties of a circular-cylindrical aerosol of caffeine were undertaken under the condition of random orientation in relation with the laser beam, and perpendicular orientation to it. A theoretical study was conducted to assess the sensitivity of aerosol to a change of shape under different polarisation modes. The aerosol optical properties, obtained previously in the laboratory, were then used to simulate the direct radiative forcing. The calculations and results were obtained by applying a one- dimensional energy-balance box model. The influence of atmospheric aerosol on the sky brightness due to a total solar eclipse was studied using the photometric and meteorological observations made during the

  15. Trial Production and Evaluation of Solar Cells Optimized for Solar Spectrum in Mars Atmosphere

    NASA Astrophysics Data System (ADS)

    Toyota, Hiroyuki; Shimada, Takanobu; Takahashi, Yu; Oyama, Akira; Washio, Hidetoshi

    2014-08-01

    We describe the production and evaluation of a prototype of an inverted metamorphic triple-junction (IMM3J) solar cell optimized for the solar spectrum on the surface of Mars. High-efficiency, flexible, lightweight solar panels containing IMM3J solar cells are promising power sources for Mars surface explorers such as rovers, landers, and airplanes. The intensity of sunlight at the Martian surface substantially decreases at wavelengths shorter than 700 nm because of absorption and scattering by the atmosphere. This decreases the output current of the InGaP top cells in state-of-the-art IMM3J solar cells, and thus decreases the overall output current. Therefore, solar cells for Mars surface explorers need to be optimized for the solar spectrum at the Martian surface. We modified IMM3J solar cells in two ways to increase the output power. We increased the thickness of the InGaP top cell to increase the light absorption, which increased the output current of the entire cell. We also increased the band gap energy of the InGaAs bottom cell by trimming the surplus current, in order to increase the output voltage. In the simulated Martian solar spectrum, the performance of the prototype solar cells was higher than that of IMM3J solar cells designed for the AM0 spectrum.

  16. Empirical Determination of Solar Proton Access to the Polar Atmosphere

    NASA Astrophysics Data System (ADS)

    Neal, Jason; Rodger, Craig; Green, Janet; Whittaker, Ian

    2014-05-01

    Violent expulsions on the Sun's surface release high energy solar protons that ultimately affect ionization levels and the local chemical composition in the upper atmosphere as well as High Frequency (HF) communication used by aircraft. The geomagnetic field screens the low altitude equatorial region, but these protons can access the atmosphere over the poles. The latitudes over which the solar protons can reach vary with geomagnetic indices such as Kp and Dst. In this study we use observations from Low Earth Orbit to determine the atmospheric access of solar protons and hence the flights paths most likely to be affected. Observations taken by up to six polar orbiting satellites during 15 solar proton events are analyzed. From this we determine 16,850 proton rigidity cutoff estimates across 3 energy channels. Empirical fits are undertaken to estimate the most likely behavior of the cutoff dependence with geomagnetic activity. We provide simple equations by which the geomagnetic latitude (spatial extent) at which the protons impact the atmosphere can be determined from a given Kp or Dst value. The variation found in the cutoff with Kp is similar to that used in existing operational models, although the changing Kp value is found to lead the variation in the cutoffs by ~3 hours .We also suggest a ~1-2° equatorward shift in latitude would provide greater accuracy. This solar proton access can be used as an input into coupled chemistry climate models and give the likely polar regions to be effected by Polar Cap Absorption (PCA) which causes HF radio 'blackout zones'. We find that a Kp predictive model can provide additional warning to the variation in proton cutoffs. Hence a prediction of the cutoff latitudes can be made ~3 hours to as much as 7 hours into the future, meeting suggested minimum planning times required by the aviation industry.

  17. Airborne interferometer for atmospheric emission and solar absorption.

    PubMed

    Keith, D W; Dykema, J A; Hu, H; Lapson, L; Anderson, J G

    2001-10-20

    The interferometer for emission and solar absorption (INTESA) is an infrared spectrometer designed to study radiative transfer in the troposphere and lower stratosphere from a NASA ER-2 aircraft. The Fourier-transform spectrometer (FTS) operates from 0.7 to 50 mum with a resolution of 0.7 cm(-1). The FTS observes atmospheric thermal emission from multiple angles above and below the aircraft. A heliostat permits measurement of solar absorption spectra. INTESA's calibration system includes three blackbodies to permit in-flight assessment of radiometric error. Results suggest that the in-flight radiometric accuracy is ~0.5 K in the mid-infrared.

  18. Effect of the shrinking dipole on solar-terrestrial energy input to the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    McPherron, R. L.

    2011-12-01

    The global average temperature of the Earth is rising rapidly. This rise is primarily attributed to the release of greenhouse gases as a result of human activity. However, it has been argued that changes in radiation from the Sun might play a role. Most energy input to the Earth is light in the visible spectrum. Our best measurements suggest this power input has been constant for the last 40 years (the space age) apart from a small 11-year variation due to the solar cycle of sunspot activity. Another possible energy input from the Sun is the solar wind. The supersonic solar wind carries the magnetic field of the Sun into the solar system. As it passes the Earth it can connect to the Earth's magnetic field whenever it is antiparallel t the Earth's field. This connection allows mass, momentum, and energy from the solar wind to enter the magnetosphere producing geomagnetic activity. Ultimately much of this energy is deposited at high latitudes in the form of particle precipitation (aurora) and heating by electrical currents. Although the energy input by this process is miniscule compared to that from visible radiation it might alter the absorption of visible radiation. Two other processes affected by the solar cycle are atmospheric entry of galactic cosmic rays (GCR) and solar energetic protons (SEP). A weak solar magnetic field at sunspot minimum facilitates GCR entry which has been implicated in creation of clouds. Large coronal mass ejections and solar flares create SEP at solar maximum. All of these alternative energy inputs and their effects depend on the strength of the Earth's magnetic field. Currently the Earth's field is decreasing rapidly and conceivably might reverse polarity in 1000 years. In this paper we describe the changes in the Earth's magnetic field and how this might affect GCR, SEP, electrical heating, aurora, and radio propagation. Whether these effects are important in global climate change can only be determined by detailed physical models.

  19. Observational Investigation of Solar Interior and Atmosphere

    NASA Technical Reports Server (NTRS)

    Kuhn, Jeffrey R.

    2003-01-01

    The Imaging Vector Magnetograph (IVM) has been modified to make it easier to observe at more than one spectral line. The cell holding the blocking filter has been replaced by a four-position filter wheel, so that changing to a different line is a matter of a few minutes rather than the several hours it used to take to disassemble the cell and install a new filter. Three new filters have been obtained, for Na 1589.6 nm, Fe 1630.25 nm, and H 1656.3 nm. The new filters have better bandpass profiles than the ones they replaced: somewhat wider, with flatter tops and steeper wings. This results in a reduction of parasitic light coming from adjacent Fabry-Perot orders, from seven percent to about two percent, and flattens the apparent continuum. The Mees CCD Imaging Spectrograph (MCCD) was upgraded under this grant, with a new control computer and data system. The camera was replaced with a faster, larger-format frame-transfer camera. Final integration of the upgrades is not yet complete, but tests indicate that the system cadence will be improved by a factor of five to ten, while increasing the spatial coverage by a factor of two (depending on observation options). Synoptic observations with the IVM and MCCD continue to be conducted daily, to the extent permitted by the fact that we have a single observer responsible for the observations. The older Haleakala Stokes Polarimeter is also used to make a daily vector magnetogram, normally of the region selected by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) duty scientists. This instrument, however, is showing its age to the extent that its maintenance is becoming something of a challenge. We also run a white light full-disk imager and a video H alpha prominence camera, continuously during times of observations. Of particular interest, we obtained rapid-cadence observations of the 2003 July 15 white light flare with both the IVM and MCCD. The vector magnetograms show no obvious difference between the

  20. Observational Investigation of Solar Interior and Atmosphere

    NASA Technical Reports Server (NTRS)

    Kuhn, Jeffrey R.

    2003-01-01

    The Imaging Vector Magnetograph (IVM) has been modified to make it easier to observe at more than one spectral line. The cell holding the blocking filter has been replaced by a four-position filter wheel, so that changing to a different line is a matter of a few minutes rather than the several hours it used to take to disassemble the cell and install a new filter. Three new filters have been obtained, for Na 1589.6 nm, Fe 1630.25 nm, and H 1656.3 nm. The new filters have better bandpass profiles than the ones they replaced: somewhat wider, with flatter tops and steeper wings. This results in a reduction of parasitic light coming from adjacent Fabry-Perot orders, from seven percent to about two percent, and flattens the apparent continuum. The Mees CCD Imaging Spectrograph (MCCD) was upgraded under this grant, with a new control computer and data system. The camera was replaced with a faster, larger-format frame-transfer camera. Final integration of the upgrades is not yet complete, but tests indicate that the system cadence will be improved by a factor of five to ten, while increasing the spatial coverage by a factor of two (depending on observation options). Synoptic observations with the IVM and MCCD continue to be conducted daily, to the extent permitted by the fact that we have a single observer responsible for the observations. The older Haleakala Stokes Polarimeter is also used to make a daily vector magnetogram, normally of the region selected by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) duty scientists. This instrument, however, is showing its age to the extent that its maintenance is becoming something of a challenge. We also run a white light full-disk imager and a video H alpha prominence camera, continuously during times of observations. Of particular interest, we obtained rapid-cadence observations of the 2003 July 15 white light flare with both the IVM and MCCD. The vector magnetograms show no obvious difference between the

  1. Detection of atmospheric Cherenkov radiation using solar heliostat mirrors

    NASA Astrophysics Data System (ADS)

    Ong, R. A.; Bhattacharya, D.; Covault, C. E.; Dixon, D. D.; Gregorich, D. T.; Hanna, D. S.; Oser, S.; Québert, J.; Smith, D. A.; Tümer, O. T.; Zych, A. D.

    1996-10-01

    There is considerable interest world-wide in developing large area atmospheric Cherenkov detectors for ground-based gamma-ray astronomy. This interest stems, in large part, from the fact that the gamma-ray energy region between 20 and 250 GeV is unexplored by any experiment. Atmospheric Cherenkov detectors offer a possible way to explore this region, but large photon collection areas are needed to achieve low energy thresholds. We are developing an experiment using the heliostat mirrors of a solar power plant as the primary collecting element. As part of this development, we built a detector using four heliostat mirrors, a secondary Fresnel lens, and a fast photon detection system. In November 1994, we used this detector to record atmospheric Cherenkov radiation produced by cosmic ray particles showering in the atmosphere. The detected rate of cosmic ray events was consistent with an energy threshold near 1 TeV. The data presented here represent the first detection of atmospheric Cherenkov radiation using solar heliostats viewed from a central tower.

  2. Particle acceleration and transport in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Kontar, Eduard

    2016-07-01

    During periods of sporadic flare activity, the Sun releases energy stored in the magnetic field into the plasma of the solar atmosphere. This is an extremely efficient process, with a large fraction of the magnetic energy going into plasma particles. The solar flares are accompanied by prompt electromagnetic emission virtually over the entire electromagnetic spectrum from gamma-rays down to radio frequencies. The Sun, through its activity, also plays a driving role in the Sun-Earth system that substantially influences geophysical space. Solar flare energetic particles from the Sun are detected in interplanetary space by in-situ measurements making them a vital component of the single Sun-Earth system. Although a qualitative picture is generally agreed upon, many processes solar flare processes are poorly understood. Specifically, the processes of acceleration and propagation of energetic particles interacting on various physical scales remain major challenges in solar physics and basic plasma physics. In the talk, I will review the current understanding of solar flare energetic particles focusing on recent observational progress, which became possible due to the numerous spacecraft and ground-based observations.

  3. Models of the Solar Atmospheric Response to Flare Heating

    NASA Technical Reports Server (NTRS)

    Allred, Joel

    2011-01-01

    I will present models of the solar atmospheric response to flare heating. The models solve the equations of non-LTE radiation hydrodynamics with an electron beam added as a flare energy source term. Radiative transfer is solved in detail for many important optically thick hydrogen and helium transitions and numerous optically thin EUV lines making the models ideally suited to study the emission that is produced during flares. I will pay special attention to understanding key EUV lines as well the mechanism for white light production. I will also present preliminary results of how the model solar atmosphere responds to Fletcher & Hudson type flare heating. I will compare this with the results from flare simulations using the standard thick target model.

  4. Atmospheric boundary layer processes during a total solar eclipse

    SciTech Connect

    SethuRaman, S.; Prabhu, A.; Narahari Rao, K.; Narasimha, R.

    1980-01-01

    The total solar eclipse that occurred over the southern part of India on February 16, 1980, gave a unique opportunity to study the earth's atmospheric boundary layer. The meteorological experiments during the 1980 solar eclipse were conducted at Raichur, India (16/sup 0/12'N, 77/sup 0/21'E) located in the state of Karnataka, approximately 400-m above sea level. The main objective was to determine the changes in the earth's atmosphere during and immediately after the eclipse. The goal was to study the changes in the momentum and heat fluxes in the boundary layer due to the eclipse. Measurements were made for 2 days prior to and 1 day after the day of the eclipse to determine background characteristics of the boundary layer which might be site-dependent.

  5. New Model Atmospheres: Testing the Solar Spectrum in the UV

    NASA Astrophysics Data System (ADS)

    Rodríguez-Merino, L. H.; Cardona, O.; Bertone, E.; Chávez, M.; Buzzoni, A.

    2009-03-01

    We present preliminary results on the calculation of synthetic spectra obtained with the stellar model atmospheres developed by Cardona, Crivellari, and Simonneau. These new models have been used as input within the Synthe series of codes developed by Kurucz. As a first step we have tested if Synthe is able to handle these models which go down to log{τ_{Ross}}= -13. We have successfully calculated a synthetic solar spectrum in the wavelength region 2000-4500 Å at high resolution (R=522 000). Within this initial test we have found that layers at optical depths with log{τ_{Ross}} < -7 significantly affect the mid-UV properties of a synthetic spectrum computed from a solar model. We anticipate that these new extended models will be a valuable tool for the analysis of UV stellar light arising from the outermost layers of the atmospheres.

  6. Solar cycle effect on atmospheric carbon dioxide levels. Final report

    SciTech Connect

    Kirk, B.L.; Rust, B.W.

    1983-01-01

    The authors present a causal time-series model for the Mauna Loa atmospheric CO2 record which supersedes a mathematical model consisting of four effects represented by exponential and sine functions. One effect is a 142-month oscillation which trails the sunspot numbers by exactly a quarter-cycle. This suggests that solar activity affects the rate of change in the atmospheric CO2 abundance. The new model replaces the mathematical functions with four measured time series representing proposed physical causes and reduces the number of adjustable parameters from 13 to 5 with no significant deterioration in the fit. The authors present evidence that solar activity affects the CO2 abundance through variations in ocean temperature or circulation.

  7. Solar geoengineering, atmospheric water vapor transport, and land plants

    NASA Astrophysics Data System (ADS)

    Caldeira, Ken; Cao, Long

    2015-04-01

    This work, using the GeoMIP database supplemented by additional simulations, discusses how solar geoengineering, as projected by the climate models, affects temperature and the hydrological cycle, and how this in turn is related to projected changes in net primary productivity (NPP). Solar geoengineering simulations typically exhibit reduced precipitation. Solar geoengineering reduces precipitation because solar geoengineering reduces evaporation. Evaporation precedes precipitation, and, globally, evaporation equals precipitation. CO2 tends to reduce evaporation through two main mechanisms: (1) CO2 tends to stabilize the atmosphere especially over the ocean, leading to a moister atmospheric boundary layer over the ocean. This moistening of the boundary layer suppresses evaporation. (2) CO2 tends to diminish evapotranspiration, at least in most land-surface models, because higher atmospheric CO2 concentrations allow leaves to close their stomata and avoid water loss. In most high-CO2 simulations, these effects of CO2 which tend to suppress evaporation are masked by the tendency of CO2-warming effect to increase evaporation. In a geoengineering simulation, with the warming effect of CO2 largely offset by the solar geoengineering, the evaporation suppressing characteristics of CO2 are no longer masked and are clearly exhibited. Decreased precipitation in solar geoengineering simulations is a bit like ocean acidification - an effect of high CO2 concentrations that is not offset by solar geoengineering. Locally, precipitation ultimately either evaporates (much of that through the leaves of plants) or runs off through groundwater to streams and rivers. On long time scales, runoff equals precipitation minus evaporation, and thus, water runoff generated at a location is equal to the net atmospheric transport of water to that location. Runoff typically occurs where there is substantial soil moisture, at least seasonally. Locations where there is enough water to maintain

  8. Equilibrium model of thin magnetic flux tubes. [solar atmosphere

    NASA Technical Reports Server (NTRS)

    Bodo, G.; Ferrari, A.; Massaglia, S.; Kalkofen, W.; Rosner, R.

    1984-01-01

    The existence of a physically realizable domain in which approximations that lead to a self consistent solution for flux tube stratification in the solar atmosphere, without ad hoc hypotheses, is proved. The transfer equation is solved assuming that no energy transport other than radiative is present. Convective motions inside the tube are assumed to be suppressed by magnetic forces. Only one parameter, the plasma beta at tau = 0, must be specified, and this can be estimated from observations of spatially resolved flux tubes.

  9. The evolution of solar ultraviolet luminosity. [influence on planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Zahnle, K. J.; Walker, J. C. G.

    1982-01-01

    Astronomical observations of stars analogous to the sun are used to construct a tentative account of the evolution of solar UV luminosity. Evidence exists that the young sun was a much more powerful source of energetic particles and radiation than it is today, and while on the main sequence, solar activity has declined as an inverse power law of age as a consequence of angular momentum loss to the solar wind. Observations of pre-main sequence stars indicate that before the sun reached the main sequence, it may have emitted as much as ten thousand times the amount of ultraviolet radiation that it does today. The impact of the results on knowledge of photochemistry and escape of constituents of primordial planetary atmospheres is discussed.

  10. Observations and Modeling of Plasma Waves in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Liu, W.; Ofman, L.; Downs, C.

    2016-12-01

    The solar atmosphere, especially the extended corona, provides rich observations of magnetohydrodynamic (MHD) waves and plasma waves in general. Such waves can be used as seismological tools to probe the physical conditions of the medium in which they travel, such as the coronal magnetic field and plasma parameters. Recent high-resolution imaging and spectroscopic observations in extreme ultraviolet (EUV) by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) and in UV by the Interface Region Imaging Spectrograph (IRIS) have opened a new chapter in understanding these waves and in utilizing them for coronal seismology. We will review such new observations of two intimately related phenomena - global EUV waves (so-called "EIT waves") associated with coronal mass ejections (CMEs) and quasi-periodic, fast-mode magnetosonic wave trains associated with flares. We will focus on the generation and propagation of global EUV waves and their interaction with coronal structures, as well as the correlation of AIA-detected fast-mode wave trains with flare pulsations seen from radio to hard X-ray wavelengths. We will also present recent MHD modeling efforts in reproducing these waves using realistic, observationally-driven simulations. We will discuss the roles of such waves in energy transport within the solar atmosphere and in their associated CME/flare eruptions.

  11. Atmospheric cosmic rays and solar energetic particles at aircraft altitudes.

    PubMed

    O'Brien, K; Friedberg, W; Sauer, H H; Smart, D F

    1996-01-01

    Galactic cosmic rays, which are thought to be produced and accelerated by a variety of mechanisms in the Milky Way galaxy, interact with the solar wind, the earth's magnetic field, and its atmosphere to produce hadron, lepton, and photon fields at aircraft altitudes that are quite unlike anything produced in the laboratory. The energy spectra of these secondary particles extend from the lowest possible energy to energies over an EeV. In addition to cosmic rays, energetic particles, generated on the sun by solar flares or coronal mass ejections, bombard the earth from time to time. These particles, while less energetic than cosmic rays, also produce radiation fields at aircraft altitudes which have qualitatively the same properties as cosmic rays. The authors have calculated atmospheric cosmic-ray angular fluxes, spectra, scalar fluxes, and ionization, and compared them with experimental data. Agreement with these data is seen to be good. These data have been used to calculate equivalent doses in a simplified human phantom at aircraft altitudes and the estimated health risks to aircraft crews. The authors have also calculated the radiation doses from several large solar energetic particle events (known as GLEs, or Ground Level Events), which took place in 1989, including the very large event known as GLE 42, which took place on September 29th and 30th of that year. The spectra incident on the atmosphere were determined assuming diffusive shock theory. Unfortunately, there are essentially no experimental data with which to compare these calculations.

  12. Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares (Invited Review)

    NASA Astrophysics Data System (ADS)

    Milligan, Ryan O.

    2015-12-01

    The extreme ultra-violet (EUV) portion of the solar spectrum contains a wealth of diagnostic tools for probing the lower solar atmosphere in response to an injection of energy, particularly during the impulsive phase of solar flares. These include temperature- and density-sensitive line ratios, Doppler-shifted emission lines, nonthermal broadening, abundance measurements, differential emission measure profiles, continuum temperatures and energetics, among others. In this article I review some of the recent advances that have been made using these techniques to infer physical properties of heated plasma at footpoint and ribbon locations during the initial stages of solar flares. I primarily focus on studies that have utilised spectroscopic EUV data from Hinode/EUV Imaging Spectrometer (EIS) and Solar Dynamics Observatory/EUV Variability Experiment (SDO/EVE), and I also provide some historical background and a summary of future spectroscopic instrumentation.

  13. Statistical equilibrium of copper in the solar atmosphere

    SciTech Connect

    Shi, J. R.; Mashonkina, L.; Zhao, G.; Gehren, T.; Zeng, J. L.

    2014-02-20

    Non-local thermodynamic equilibrium (NLTE) line formation for neutral copper in the one-dimensional solar atmospheres is presented for the atomic model, including 96 terms of Cu I and the ground state of Cu II. The accurate oscillator strengths for all the line transitions in model atom and photoionization cross sections were calculated using the R-matrix method in the Russell-Saunders coupling scheme. The main NLTE mechanism for Cu I is the ultraviolet overionization. We find that NLTE leads to systematically depleted total absorption in the Cu I lines and, accordingly, positive abundance corrections. Inelastic collisions with neutral hydrogen atoms produce minor effects on the statistical equilibrium of Cu I in the solar atmosphere. For the solar Cu I lines, the departures from LTE are found to be small, the mean NLTE abundance correction of ∼0.01 dex. It was found that the six low-excitation lines, with excitation energy of the lower level E {sub exc} ≤ 1.64 eV, give a 0.14 dex lower mean solar abundance compared to that from the six E {sub exc} > 3.7 eV lines, when applying experimental gf-values of Kock and Richter. Without the two strong resonance transitions, the solar mean NLTE abundance from 10 lines of Cu I is log ε{sub ☉}(Cu) = 4.19 ± 0.10, which is consistent within the error bars with the meteoritic value 4.25 ± 0.05 of Lodders et al. The discrepancy between E {sub exc} = 1.39-1.64 eV and E {sub exc} > 3.7 eV lines can be removed when the calculated gf-values are adopted and a mean solar abundance of log ε{sub ☉}(Cu) = 4.24 ± 0.08 is derived.

  14. Solar forcing, implications for the Terrestrial planets - Earth, Venus and Mars

    NASA Astrophysics Data System (ADS)

    Lundin, R.

    2009-09-01

    Solar forcing by x-ray, FUV, EUV and the solar wind, have major implications for planets orbiting near the Sun. After solar system formation to present times, the accumulated radiation and solar wind has substantially modified the volatile inventory of the Terrestrial planets. The effect is most pronounced for Mercury and Venus, but significant also for Mars. Earth is an exception. Why so, is a pending question with no obvious answer, and does this have a bearing on today's climate change? Solar forcing is known to lead to mass loss of atmospheric constituents, such as hydrogen and oxygen. From satellite instruments orbiting Earth, Mars and Venus we have gained substantial knowledge of such mass losses. The mass loss from the Earth primarily originates from water. More recent results suggest that the same applies for Mars and Venus, despite water being a minor constituent in the atmosphere of these planets. Water therefore appears to be an important marker, bearing the signature of the past planetary evolution. Conversely, carbon dioxide, the major molecule in the atmosphere of Mars and Venus, seems more resistant to solar forcing. Since carbon dioxide plays a major role in today's discussion on Earth's climate change, the atmospheric evolution of Mars and Venus must be considered an interesting reference to climate change. This is particularly relevant considering the complexity of solar forcing of the Terrestrial planets. In this talk aspects of how solar forcing affects Earth, Venus and Mars will be discussed. Particular emphasis is put on the impact of solar variability on the mass loss and the electromagnetic coupling between the Sun and the planets.

  15. The ancient oxygen exosphere of Mars - Implications for atmosphere evolution

    NASA Astrophysics Data System (ADS)

    Zhang, M. H. G.; Luhmann, J. G.; Bougher, S. W.; Nagy, A. F.

    1993-06-01

    The paper considers absorption of oxygen (atoms and ions) by the surface as a mechanism for the early Martian atmosphere escape, due to the effect of high EUV flux of the ancient sun. Hot oxygen exosphere densities in ancient atmosphere and ionosphere are calculated for different EUV fluxes and the escape fluxes associated with these exposures. Using these densities, the ion production rate above the ionopause is calculated for different epochs including photoionization, charge exchange, and solar wind electron impact. It is found that, when the inferred high solar EUV fluxes of the past are taken into account, oxygen equivalent to that in several tens of meters of water, planet-wide, should have escaped Martian atmosphere to space over the last 3 Gyr.

  16. Global Forces in Eruptive Solar Flares: The Lorentz Force Acting on the Solar Atmosphere and the Solar Interior

    NASA Astrophysics Data System (ADS)

    Fisher, George H.; Bercik, D. J.; Welsch, B. T.; Hudson, H. S.

    2012-05-01

    We compute the change in the Lorentz force integrated over the outer solar atmosphere implied by observed changes in vector magnetograms that occur during large, eruptive solar flares. This force perturbation should be balanced by an equal and opposite force perturbation acting on the solar photosphere and solar interior. The resulting expression for the estimated force change in the solar interior generalizes the earlier expression presented by Hudson, Fisher, and Welsch, providing horizontal as well as vertical force components, and provides a more accurate result for the vertical component of the perturbed force. We show that magnetic eruptions should result in the magnetic field at the photosphere becoming more horizontal, and hence should result in a downward (toward the solar interior) force change acting on the photosphere and solar interior, as recently argued from an analysis of magnetogram data by Wang and Liu. We suggest the existence of an observational relationship between the force change computed from changes in the vector magnetograms, the outward momentum carried by the ejecta from the flare, and the properties of the helioseismic disturbance driven by the downward force change. We use the impulse driven by the Lorentz-force change in the outer solar atmosphere to derive an upper limit to the mass of erupting plasma that can escape from the Sun. Finally, we compare the expected Lorentz-force change at the photosphere with simple estimates from flare-driven gasdynamic disturbances and from an estimate of the perturbed pressure from radiative backwarming of the photosphere in flaring conditions.

  17. The statistical properties of vortex flows in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Wedemeyer, Sven; Kato, Yoshiaki; Steiner, Oskar

    2015-08-01

    Rotating magnetic field structures associated with vortex flows on the Sun, also known as “magnetic tornadoes”, may serve as waveguides for MHD waves and transport mass and energy upwards through the atmosphere. Magnetic tornadoes may therefore potentially contribute to the heating of the upper atmospheric layers in quiet Sun regions.Magnetic tornadoes are observed over a large range of spatial and temporal scales in different layers in quiet Sun regions. However, their statistical properties such as size, lifetime, and rotation speed are not well understood yet because observations of these small-scale events are technically challenging and limited by the spatial and temporal resolution of current instruments. Better statistics based on a combination of high-resolution observations and state-of-the-art numerical simulations is the key to a reliable estimate of the energy input in the lower layers and of the energy deposition in the upper layers. For this purpose, we have developed a fast and reliable tool for the determination and visualization of the flow field in (observed) image sequences. This technique, which combines local correlation tracking (LCT) and line integral convolution (LIC), facilitates the detection and study of dynamic events on small scales, such as propagating waves. Here, we present statistical properties of vortex flows in different layers of the solar atmosphere and try to give realistic estimates of the energy flux which is potentially available for heating of the upper solar atmosphere

  18. Lifting Entry & Atmospheric Flight (LEAF) Applications at Solar System Bodies.

    NASA Astrophysics Data System (ADS)

    Lee, G.; Sen, B.; Polidan, R. S.

    2015-12-01

    Introduction: Northrop Grumman and L'Garde have continued the development of a hypersonic entry, maneuverable platform capable of performing long-duration (months to a year) in situ and remote measurements at any solar system body that possesses an atmosphere. The Lifting Entry & Atmospheric Flight (LEAF) family of vehicles achieve this capability by using a semi-buoyant, ultra-low ballistic coefficient vehicle whose lifting entry allows it to enter the atmosphere without an aeroshell. In this presentation, we discuss the application of the LEAF system at various solar system bodies: Venus, Titan, Mars, and Earth. We present the key differences in platform design as well as operational differences required by the various target environments. The Venus implementation includes propulsive capability to reach higher altitudes during the day and achieves full buoyancy in the "habitable layers" of Venus' atmosphere at night. Titan also offers an attractive operating environment, allowing LEAF designs that can target low, medium, or high altitude operations, also with propulsive capabilities to roam within each altitude regime. The Mars version is a glider that descends gradually, allowing targeted delivery of payloads to the surface. Finally, an Earth version could remain in orbit in a stowed state until activated, allowing rapid response type deployments to any region of the globe.

  19. Searching for Motion within the Solar Atmosphere (Abstract)

    NASA Astrophysics Data System (ADS)

    Oatney, S. N.

    2015-12-01

    (Abstract only) The mystery of heat transfer within the solar atmosphere has long been a subject of study and debate. Not unlike large solar observatories that are funded by public monies, amateur solar observers also have a keen interest in this subject and are able to creatively employ tools at hand such as a two slit interferometer used to create interference lines in an attempt to measure motion. (Interference patterns: https://en.wikipedia.org/wiki/Double-slit_experiment) With a 6-inch equatorially pier mounted refractor focused just above the visible disk of the sun, images taken with a Meade Lunar Planetary Imager video LPI CMOS camera at ~30 Hz sample rates and stored as FITS files. A variety of photometry, unrated color, and full aperture solar filters are combined with and without a two slit interferometer placed at the focus of the telescope. These images, explored through the NASA FITS viewer (https://heasarc.gsfc.nasa.gov/docs/software/ftools/fv/) were applied to show logarithmic color contours. Selected fv images were placed consecutively in a movie format that shows some cyclical motion around and between the contours, mostly of the solar corona.

  20. Atmospheric environmental implications of propulsion systems

    SciTech Connect

    Mcdonald, A.J.; Bennett, R.R.

    1995-03-01

    Three independent studies have been conducted for assessing the impact of rocket launches on the earth`s environment. These studies have addressed issues of acid rain in the troposphere, ozone depletion in the stratosphere, toxicity of chemical rocket exhaust products, and the potential impact on global warming from carbon dioxide emissions from rocket launches. Local, regional, and global impact assessments were examined and compared with both natural sources and anthropogenic sources of known atmospheric pollutants with the following conclusions: (1) Neither solid nor liquid rocket launches have a significant impact on the earth`s global environment, and there is no real significant difference between the two. (2) Regional and local atmospheric impacts are more significant than global impacts, but quickly return to normal background conditions within a few hours after launch. And (3) vastly increased space launch activities equivalent to 50 U.S. Space Shuttles or 50 Russian Energia launches per year would not significantly impact these conclusions. However, these assessments, for the most part, are based upon homogeneous gas phase chemistry analysis; heterogeneous chemistry from exhaust particulates, such as aluminum oxide, ice contrails, soot, etc., and the influence of plume temperature and afterburning of fuel-rich exhaust products, need to be further addressed. It was the consensus of these studies that computer modeling of interactive plume chemistry with the atmosphere needs to be improved and computer models need to be verified with experimental data. Rocket exhaust plume chemistry can be modified with propellant reformulation and changes in operating conditions, but, based upon the current state of knowledge, it does not appear that significant environmental improvements from propellant formulation changes can be made or are warranted.

  1. Using the SDO Atmospheric Imaging Assembly to Study Solar Activity

    NASA Astrophysics Data System (ADS)

    Lemen, James

    2014-01-01

    The Atmospheric Imaging Assembly (AIA) is one of the instruments on board NASA’s flagship Solar Dynamics Observatory (SDO) mission that was launched in February 2010. AIA achieves 1.5 arcsec spatial resolution of the entire solar corona with 12-second temporal resolution in seven extreme ultraviolet (EUV) band passes centered on specific lines: Fe XVIII (94 Å), Fe VIII, XXI (131 Å), Fe IX (171 Å), Fe XII, XXIV (193 Å), Fe XIV (211 Å), He II (304 Å) and Fe XVI (335 Å) one band pass observes C IV (near 1600 Å). In the past 3 years AIA has produced over 77M images and 1,200 Tbytes of data that have challenged and clarified our understanding of the solar corona, specifically how the solar magnetic field drives coronal evolution on various scales. Multi-temperature, low-noise, full-Sun observations have captured solar eruptions and flares, coronal field oscillations (in loops and filaments), fast-mode waves (up to 2,000 km/s), plasma instabilities, and a rare view of comet interactions with the corona. Comparison with data from other instruments, such as SDO EUV Variability Experiment (EVE), and with numerical models, provides the ability to develop a comprehensive understanding of solar activity and evolution. And the comparison of the information-rich spatial content of the AIA observations with EVE spectra is instructive for similar studies of stellar targets. The NASA heliophysics open-data policy enables wide-scale participation by the international community. As the time base of AIA observations and magnetic data obtained from the companion SDO Helioseismic and Magnetic Imager (HMI) increases to a good fraction of the solar dynamo cycle time scale, we anticipate that the value of the SDO data will be similarly magnified. We present highlights that have been gleaned from this already exceptional mission. http://sdowww.lmsal.com

  2. Reconnection in the lower solar atmosphere and coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Wang, Jingxiu

    2006-01-01

    In 1985, a phenomenon in the solar photosphere, called magnetic flux cancellation, was first described in detail by Livi et al. (1985) [The cancellation of magnetic flux. I On the quiet sun, Aust. J. Phys. 38, 855 873, 1985] and Martin et al. (1985) [The cancellation of magnetic flux. II In a decaying active region, Aust. J. Phys. 38, 929 959, 1985]. Since then, it has been revealed that flux cancellation is intrinsically correlated to most, if not all, types of solar activity, such as flare, filament formation and eruption, and ubiquitous small-scale activity, e.g., X-ray bright point, explosive event, mini-filament eruption and so on. Only recently, it was discovered that flux cancellation appeared to be a key part of magnetic evolution leading to the initiation of coronal mass ejections (CMEs) [Zhang et al., Magnetic flux cancellation associated withthe major solar event on 2000 July 14. Astrophys. J. 548, L99 102, 2001; Zhang et al., 2001b. Filament-associated halo coronal mass ejection, Chin. J. Astron. Astrophys., 1, 85 98, 2001; Zhang and Wang, Filament eruptions and halo coronal mass ejections, Astrophys. J. 554, 474 487, 2001]. On the other hand, the nature of flux cancellation has been a topic of persistent interest and debate. We review the observational properties of magnetic flux cancellation and the relevant theoretical studies, describe the vector magnetic field changes in flux cancellation in CME-associated active regions (ARs), and demonstrate that the well-observed flux cancellations fit nicely the scenario of magnetic reconnection in the lower solar atmosphere. It is suggested that magnetic reconnection in the lower solar atmosphere is a ubiquitous process on the Sun. It is a key element in the magnetic evolution of CMEs.

  3. Solar activity impact on the Earth's upper atmosphere

    NASA Astrophysics Data System (ADS)

    Kutiev, Ivan; Tsagouri, Ioanna; Perrone, Loredana; Pancheva, Dora; Mukhtarov, Plamen; Mikhailov, Andrei; Lastovicka, Jan; Jakowski, Norbert; Buresova, Dalia; Blanch, Estefania; Andonov, Borislav; Altadill, David; Magdaleno, Sergio; Parisi, Mario; Miquel Torta, Joan

    2013-02-01

    The paper describes results of the studies devoted to the solar activity impact on the Earth's upper atmosphere and ionosphere, conducted within the frame of COST ES0803 Action. Aim: The aim of the paper is to represent results coming from different research groups in a unified form, aligning their specific topics into the general context of the subject. Methods: The methods used in the paper are based on data-driven analysis. Specific databases are used for spectrum analysis, empirical modeling, electron density profile reconstruction, and forecasting techniques. Results: Results are grouped in three sections: Medium- and long-term ionospheric response to the changes in solar and geomagnetic activity, storm-time ionospheric response to the solar and geomagnetic forcing, and modeling and forecasting techniques. Section 1 contains five subsections with results on 27-day response of low-latitude ionosphere to solar extreme-ultraviolet (EUV) radiation, response to the recurrent geomagnetic storms, long-term trends in the upper atmosphere, latitudinal dependence of total electron content on EUV changes, and statistical analysis of ionospheric behavior during prolonged period of solar activity. Section 2 contains a study of ionospheric variations induced by recurrent CIR-driven storm, a case-study of polar cap absorption due to an intense CME, and a statistical study of geographic distribution of so-called E-layer dominated ionosphere. Section 3 comprises empirical models for describing and forecasting TEC, the F-layer critical frequency foF2, and the height of maximum plasma density. A study evaluates the usefulness of effective sunspot number in specifying the ionosphere state. An original method is presented, which retrieves the basic thermospheric parameters from ionospheric sounding data.

  4. The Influence of Large Solar Proton Events on the Atmosphere

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.

    2012-01-01

    Solar proton events (SPEs) can cause changes in constituents in the Earth s polar middle atmosphere. A number of large SPEs have occurred over the past 50 years and tend to happen most frequently near solar maximum. The highly energetic protons cause ionizations, excitations, dissociations, and dissociative ionizations of the background constituents. Complicated ion chemistry leads to HOx (H, OH, HO2) production and dissociation of N2 leads to NOy (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2) production. Both the HOx and NOy increases can result in changes to ozone in the stratosphere and mesosphere. The HOx increases lead to short-lived (days) ozone decreases in the mesosphere and upper stratosphere. The NOy increases lead to long-lived (several months) stratospheric ozone changes because of the long lifetime of NOy constituents in this region. UARS HALogen Occultation Experiment (HALOE) instrument observations showed SPE-caused polar stratospheric NOx (NO+NO2) increases over 10 ppbv in September 2000 due to the very large SPE of July 2000, which are reasonably well simulated with the Whole Atmosphere Community Climate Model (WACCM). WACCM-computed SPE-caused polar stratospheric ozone decreases >10% continued for up to 5 months past the largest events in the past 50 years, however, SPE-caused total ozone changes were not found to be statistically significant. Small polar middle atmospheric temperature changes of <4 K have also been predicted to occur as a result of the larger SPEs. The polar atmospheric effects of large SPEs during solar cycle 23 and 24 will be emphasized in this presentation.

  5. Atmospheric environmental implications of propulsion systems

    NASA Technical Reports Server (NTRS)

    Mcdonald, Allan J.; Bennett, Robert R.

    1995-01-01

    Three independent studies have been conducted for assessing the impact of rocket launches on the earth's environment. These studies have addressed issues of acid rain in the troposphere, ozone depletion in the stratosphere, toxicity of chemical rocket exhaust products, and the potential impact on global warming from carbon dioxide emissions from rocket launches. Local, regional, and global impact assessments were examined and compared with both natural sources and anthropogenic sources of known atmospheric pollutants with the following conclusions: (1) Neither solid nor liquid rocket launches have a significant impact on the earth's global environment, and there is no real significant difference between the two. (2) Regional and local atmospheric impacts are more significant than global impacts, but quickly return to normal background conditions within a few hours after launch. And (3) vastly increased space launch activities equivalent to 50 U.S. Space Shuttles or 50 Russian Energia launches per year would not significantly impact these conclusions. However, these assessments, for the most part, are based upon homogeneous gas phase chemistry analysis; heterogeneous chemistry from exhaust particulates, such as aluminum oxide, ice contrails, soot, etc., and the influence of plume temperature and afterburning of fuel-rich exhaust products, need to be further addressed. It was the consensus of these studies that computer modeling of interactive plume chemistry with the atmosphere needs to be improved and computer models need to be verified with experimental data. Rocket exhaust plume chemistry can be modified with propellant reformulation and changes in operating conditions, but, based upon the current state of knowledge, it does not appear that significant environmental improvements from propellant formulation changes can be made or are warranted. Flight safety, reliability, and cost improvements are paramount for any new rocket system, and these important aspects

  6. Sensitivity of the atmospheric lapse rate to solar cloud absorption in a radiative-convective model

    NASA Astrophysics Data System (ADS)

    Erlick, Carynelisa; Ramaswamy, V.

    2003-08-01

    Previous radiative-convective model studies of the radiative forcing due to absorbing aerosols such as soot and dust have revealed a strong dependence on the vertical distribution of the absorbers. In this study, we extend this concept to absorption in cloud layers, using a one-dimensional radiative-convective model employing high, middle, and low cloud representations to investigate the response of the surface temperature and atmospheric lapse rate to increases in visible cloud absorption. The visible single-scattering albedo (ssa) of the clouds is prescribed, ranging from 1.0 to 0.6, where 0.99 is the minimum that would be expected from the presence of absorbing aerosols within the cloud drops on the basis of recent Monterey Area Ship Track (MAST) Experiment case studies. Simulations are performed with respect to both a constant cloud optical depth and an increasing cloud optical depth and as a function of cloud height. We find that increases in solar cloud absorption tend to warm the troposphere and surface and stabilize the atmosphere, while increases in cloud optical depth cool the troposphere and surface and slightly stabilize the atmosphere between the low cloud top and surface because of the increase in surface cooling. In the absence of considerations involving microphysical or cloud-climate feedbacks, we find that two conditions are required to yield an inversion from a solar cloud absorption perturbation: (1) The solar absorption perturbation must be included throughout the tropospheric clouds column, distributing the solar heating to higher altitudes, and (2) the ssa of the clouds must be ≤0.6, which is an unrealistically low value. The implication is that there is very little possibility of significant stabilization of the global mean atmosphere due to perturbation of cloud properties given current ssa values.

  7. Which Solar and Geomagnetic Drivers Control Earth's Upper Atmosphere Thermostat?

    NASA Astrophysics Data System (ADS)

    Knipp, D.; Mlynczak, M. G.; McGranaghan, R. M.; Kilcommons, L. M.

    2015-12-01

    Nitric Oxide (NO) is a trace component of Earth's upper atmosphere that allows Earth's thermosphere to cool in response to energy input from solar extreme ultraviolet (EUV) photons and geomagnetic activity. When created and excited, NO molecules provide a natural thermostat via infrared radiative emissions [Kockarts, 1980]. A record of this cooling over the last 13 years has been provided by Mlynczak et al. [2014]. Nitric Oxide emissions in concert with EUV photons, auroral particles, and neutral thermosphere circulation determine if geomagnetic storms will deliver a sudden powerful upheaval of Earth's upper atmosphere or a damped event. In this talk I will review recent findings about the forecastability of solar and magnetospheric control of this important thermospheric trace constituent. In particular, I will discuss the role of pseudo-streamers and helmet streamers in the solar wind, and the possible role of magnetic cloud orientation, in determining the extent of thermospheric NO storm response. Anticipating the thermospheric NO response to geomagnetic storms is a next step in improving satellite drag forecasting.

  8. Atmospheric extinction in simulation tools for solar tower plants

    NASA Astrophysics Data System (ADS)

    Hanrieder, Natalie; Wilbert, Stefan; Schroedter-Homscheidt, Marion; Schnell, Franziska; Guevara, Diana Mancera; Buck, Reiner; Giuliano, Stefano; Pitz-Paal, Robert

    2017-06-01

    Atmospheric extinction causes significant radiation losses between the heliostat field and the receiver in a solar tower plants. These losses vary with site and time. State of the art is that in ray-tracing and plant optimization tools, atmospheric extinction is included by choosing between few constant standard atmospheric conditions. Even though some tools allow the consideration of site and time dependent extinction data, such data sets are nearly never available. This paper summarizes and compares the most common model equations implemented in several ray-tracing tools. There are already several methods developed and published to measure extinction on-site. An overview of the existing methods is also given here. Ray-tracing simulations of one exemplary tower plant at the Plataforma Solar de Almería (PSA) are presented to estimate the plant yield deviations between simulations using standard model equations instead of extinction time series. For PSA, the effect of atmospheric extinction accounts for losses between 1.6 and 7 %. This range is caused by considering overload dumping or not. Applying standard clear or hazy model equations instead of extinction time series lead to an underestimation of the annual plant yield at PSA. The discussion of the effect of extinction in tower plants has to include overload dumping. Situations in which overload dumping occurs are mostly connected to high radiation levels and low atmospheric extinction. Therefore it can be recommended that project developers should consider site and time dependent extinction data especially on hazy sites. A reduced uncertainty of the plant yield prediction can significantly reduce costs due to smaller risk margins for financing and EPCs. The generation of extinction data for several locations in form of representative yearly time series or geographical maps should be further elaborated.

  9. Ozone changes under solar geoengineering: implications for UV exposure and air quality

    NASA Astrophysics Data System (ADS)

    Nowack, P. J.; Abraham, N. L.; Braesicke, P.; Pyle, J. A.

    2015-11-01

    Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term Solar Radiation Management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks such as ozone changes under this scenario. Including the composition changes, we find large reductions in surface UV-B irradiance, with implications for vitamin D production, and increases in surface ozone concentrations, both of which could be important for human health. We highlight that both tropospheric and stratospheric ozone changes should be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

  10. Solar Wind Interaction with the Martian Upper Atmosphere at Early Mars/Extreme Solar Conditions

    NASA Astrophysics Data System (ADS)

    Dong, C.; Bougher, S. W.; Ma, Y.; Toth, G.; Lee, Y.; Nagy, A. F.; Tenishev, V.; Pawlowski, D. J.; Combi, M. R.

    2014-12-01

    The investigation of ion escape fluxes from Mars, resulting from the solar wind interaction with its upper atmosphere/ionosphere, is important due to its potential impact on the long-term evolution of Mars atmosphere (e.g., loss of water) over its history. In the present work, we adopt the 3-D Mars cold neutral atmosphere profiles (0 ~ 300 km) from the newly developed and validated Mars Global Ionosphere Thermosphere Model (M-GITM) and the 3-D hot oxygen profiles (100 km ~ 5 RM) from the exosphere Monte Carlo model Adaptive Mesh Particle Simulator (AMPS). We apply these 3-D model output fields into the 3-D BATS-R-US Mars multi-fluid MHD (MF-MHD) model (100 km ~ 20 RM) that can simulate the interplay between Mars upper atmosphere and solar wind by considering the dynamics of individual ion species. The multi-fluid MHD model solves separate continuity, momentum and energy equations for each ion species (H+, O+, O2+, CO2+). The M-GITM model together with the AMPS exosphere model take into account the effects of solar cycle and seasonal variations on both cold and hot neutral atmospheres. This feature allows us to investigate the corresponding effects on the Mars upper atmosphere ion escape by using a one-way coupling approach, i.e., both the M-GITM and AMPS model output fields are used as the input for the multi-fluid MHD model and the M-GITM is used as input into the AMPS exosphere model. In this study, we present M-GITM, AMPS, and MF-MHD calculations (1-way coupled) for 2.5 GYA conditions and/or extreme solar conditions for present day Mars (high solar wind velocities, high solar wind dynamic pressure, and high solar irradiance conditions, etc.). Present day extreme conditions may result in MF-MHD outputs that are similar to 2.5 GYA cases. The crustal field orientations are also considered in this study. By comparing estimates of past ion escape rates with the current ion loss rates to be returned by the MAVEN spacecraft (2013-2016), we can better constrain the

  11. Drag of the Venusian Atmosphere by Solar Wind

    NASA Astrophysics Data System (ADS)

    Durand-Manterol, H.

    2006-12-01

    One of the more efficient mechanisms of volatiles lost in the non-magnetic planets is its drag by solar wind. In this study it is explored this type of erosion for Venus and it is obtained some numerical results leaving from plausible models of degassing and drag. The obtained results from this study are: Venus had degassed, in all its history, of the order of 286.87 TAM of volatiles (1 TAM = 1 Terrestrial Atmospheric Mass = 5.28x1018 kg), i.e., 1.515x1021 kg. Since current mass of the planet's atmosphere is 89.92 TAM the volatiles mass that Venus has lost in the same period is of the order of 196.95 TAM, i.e., 1.04x1021 kg. The drag capacity of the solar wind in the first Ga of the planet's life was very large such that it could drag of the order of 108 TAM if Venus had have it. Degasification did not could compete with the drag that maintains the planet free of volatiles and at the solar wind flowing directly in surface. After this first Ga in the following 3.6 Ga the drag capacity of the solar wind reduced drastically and then the solar wind only could drag at the most of the order of 88 TAM of volatiles. The mass dragged by the solar wind in all the history of Venus fluctuate between 70 and 200 TAM, i.e., between 3.7x1020 kg and 1.06x1021 kg. In last 3.6 Ga the dragged mass by solar wind fluctuate between 11 and 61 TAM and y the last 500 Ma between 0.32 and 0.41 TAM. The lost by other mechanisms fluctuate between 1 and 130 TAM. For the scenarios of more loss the usual mechanisms could not explain the quantity of lost volatiles, for this it is proposed the hypotheses of the Great Impact (the collision of Venus with a body larger than Moon 500 Ma ago) this hypotheses not only explain the lost of volatiles but also other aspects do not understand of Venus, like its slowly and retrograde rotation and the renovation of all its surface 500 Ma ago.

  12. Solar pressure and molecular decay in cometary atmospheres

    NASA Technical Reports Server (NTRS)

    Beard, D. B.; Whelan, T. A.; Gast, M. A.

    1985-01-01

    The effects of solar pressure and molecular decay on number density in cometary atmospheres are rigorously separated and scale lengths for each are determined from an analysis of observed brightness profiles in the solar and antisolar directions. It is found that the pressure scale length of CN is approximately 160,000 km and that of C2 is approximately 110,000 km. The scale length for molecular decay, heretofore incorrectly inferred from the observational data, is approximately 3 times as long as the pressure scale lengths. It is difficult to determine adequately from observations that extend no more than about 100,000 km from the comet nucleus. The scale length for molecular decay by photodissociation or whatever cause is found to be about 350,000 km for C2 and 500,000 km for CN.

  13. Wave motions and wave heating in the upper solar atmosphere

    NASA Astrophysics Data System (ADS)

    Poletto, G.

    The experimental and theoretical evidence favoring the wave heating mechanism in the low chromosphere is briefly reviewed, and the possibility of maintaining this mechanism, with proper modifications, in the higher layer is studied. Wave mode candidates for heating at high levels are analyzed, including gravity waves and Alfven waves. Waves in the upper chromosphere and the transition region are considered, showing power spectra of oscillations in lines forming at increasing heights in the solar atmosphere, fluctuations in UV line intensity, the predicted relationship between velocity and intensity modulation for acoustic waves, and sample results from UV spectrometer and polarimeter observations. It is concluded that in the upper chromosphere and transition regions, observations fail to reveal an acoustic flux adequate to compensate for the energy losses in these layers. Alfven waves, observed in the solar wind, could supply the required energy flux, but their presence cannot either be confirmed or ruled out.

  14. Theoretical studies of the physics of the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Hollweg, Joseph V.

    1992-01-01

    Significant advances in our theoretical basis for understanding several physical processes related to dynamical phenomena on the sun were achieved. We have advanced a new model for spicules and fibrils. We have provided a simple physical view of resonance absorption of MHD surface waves; this allowed an approximate mathematical procedure for obtaining a wealth of new analytical results which we applied to coronal heating and p-mode absorption at magnetic regions. We provided the first comprehensive models for the heating and acceleration of the transition region, corona, and solar wind. We provided a new view of viscosity under coronal conditions. We provided new insights into Alfven wave propagation in the solar atmosphere. And recently we have begun work in a new direction: parametric instabilities of Alfven waves.

  15. Solar Flux Deposition And Heating Rates In Jupiter's Atmosphere

    NASA Astrophysics Data System (ADS)

    Perez-Hoyos, Santiago; Sánchez-Lavega, A.

    2009-09-01

    We discuss here the solar downward net flux in the 0.25 - 2.5 µm range in the atmosphere of Jupiter and the associated heating rates under a number of vertical cloud structure scenarios focusing in the effect of clouds and hazes. Our numerical model is based in the doubling-adding technique to solve the radiative transfer equation and it includes gas absorption by CH4, NH3 and H2, in addition to Rayleigh scattering by a mixture of H2 plus He. Four paradigmatic Jovian regions have been considered (hot-spots, belts, zones and Polar Regions). The hot-spots are the most transparent regions with downward net fluxes of 2.5±0.5 Wm-2 at the 6 bar level. The maximum solar heating is 0.04±0.01 K/day and occurs above 1 bar. Belts and zones characterization result in a maximum net downward flux of 0.5 Wm-2 at 2 bar and 0.015 Wm-2 at 6 bar. Heating is concentrated in the stratospheric and tropospheric hazes. Finally, Polar Regions are also explored and the results point to a considerable stratospheric heating of 0.04±0.02 K/day. In all, these calculations suggest that the role of the direct solar forcing in the Jovian atmospheric dynamics is limited to the upper 1 - 2 bar of the atmosphere except in the hot-spot areas. Acknowledgments: This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07.

  16. UV photochemistry of DNA in vitro and in Bacillus subtilis spores at earth-ambient and low atmospheric pressure: implications for spore survival on other planets or moons in the solar system.

    PubMed

    Nicholson, Wayne L; Setlow, Barbara; Setlow, Peter

    2002-01-01

    Two major parameters influencing the survival of Bacillus subtilis spores in space and on bodies within the Solar System are UV radiation and vacuum, both of which induce inactivating damage to DNA. To date, however, spore survival and DNA photochemistry have been explored only at the extremes of Earth-normal atmospheric pressure (101.3 kPa) and at simulated space vacuum (10(-3)-10(-6) Pa). In this study, wild-type spores, mutant spores lacking alpha/beta-type small, acid-soluble spore proteins (SASP), naked DNA, and complexes between SASP SspC and DNA were exposed simultaneously to UV (254 nm) at intermediate pressure (1-2 Pa), and the UV photoproducts cis,syn-thymine-thymine cyclobutane dimer (c,sTT), trans,syn-thymine-thymine cyclobutane dimer (t,sTT), and "spore photoproduct" (SP) were quantified. At 101.3 kPa, UV-treated wild-type spores accumulated only SP, but spores treated with UV radiation at 1-2 Pa exhibited a spectrum of DNA damage similar to that of spores treated at 10(-6) Pa, with accumulation of SP, c,sTT, and t,sTT. The presence or absence of alpha/beta-type SASP in spores was partly responsible for the shift observed between levels of SP and c,sTT, but not t,sTT. The changes observed in spore DNA photochemistry at 1-2 Pa in vivo were not reproduced by irradiation of naked DNA or SspC:DNA complexes in vitro, suggesting that factors other than SASP are involved in spore DNA photochemistry at low pressure.

  17. UV and EUV spectroscopy of the upper solar atmosphere.

    NASA Astrophysics Data System (ADS)

    Mason, H. E.

    The UV and EUV wavelength regions are rich in emission lines from the transition region and the corona. Spectroscopic diagnostic techniques have been used extensively to determine the physical conditions in the solar atmosphere for such diverse phenomena as coronal holes, active regions surges, flares. The author reviews diagnostic techniques which have been used in the analyses of space observations (eg Skylab, SMM, HRTS, CHASE) and looks to future projects such as the CDS and SUMER instruments on SOHO which cover the UV and EUV wavelength regions and will provide a wealth of observations with excellent spatial, spectral and temporal resolution.

  18. Supersymmetric resolution of solar and atmospheric neutrino puzzles

    SciTech Connect

    Drees, M.; Pakvasa, S.; Tata, X.; ter Veldhuis, T.

    1998-05-01

    Renormalizable lepton number violating interactions that break R parity can induce a Majorana mass for neutrinos. Based on this, we show that it is possible to obtain a phenomenologically viable neutrino mass matrix that can accommodate atmospheric neutrino data via {nu}{sub {mu}}-{nu}{sub {tau}} mixing and the solar neutrino data via either the large or small angle MSW effect. We argue that such a mass matrix could result from an approximate discrete symmetry of the superpotential that forbids renormalizable baryon number violating couplings. {copyright} {ital 1998} {ital The American Physical Society}

  19. Lifting Entry & Atmospheric Flight (LEAF) System Concept Applications at Solar System Bodies With an Atmosphere

    NASA Astrophysics Data System (ADS)

    Lee, Greg; Polidan, Ronald; Ross, Floyd; Sokol, Daniel; Warwick, Steve

    2015-11-01

    Northrop Grumman and L’Garde have continued the development of a hypersonic entry, semi-buoyant, maneuverable platform capable of performing long-duration (months to a year) in situ and remote measurements at any solar system body that possesses an atmosphere.The Lifting Entry & Atmospheric Flight (LEAF) family of vehicles achieves this capability by using a semi-buoyant, ultra-low ballistic coefficient vehicle whose lifting entry allows it to enter the atmosphere without an aeroshell. The mass savings realized by eliminating the heavy aeroshell allows significantly more payload to be accommodated by the platform for additional science collection and return.In this presentation, we discuss the application of the LEAF system at various solar system bodies: Venus, Titan, Mars, and Earth. We present the key differences in platform design as well as operational differences required by the various target environments. The Venus implementation includes propulsive capability to reach higher altitudes during the day and achieves full buoyancy in the mid-cloud layer of Venus’ atmosphere at night.Titan also offers an attractive operating environment, allowing LEAF designs that can target low or medium altitude operations, also with propulsive capabilities to roam within each altitude regime. The Mars version is a glider that descends gradually, allowing targeted delivery of payloads to the surface or high resolution surface imaging. Finally, an Earth version could remain in orbit in a stowed state until activated, allowing rapid response type deployments to any region of the globe.

  20. Atmospheric Solar Absorption measurements in the lowest 3-km of the atmosphere with small UAVs

    NASA Astrophysics Data System (ADS)

    Ramana, M. V.; Ramanathan, V.; Roberts, G.; Corrigan, C.; Nguyen, H. V.; McFarquhar, G.

    2007-12-01

    This paper reports unique measurements of atmospheric solar absorption and heating rates in the visible (0.4- 0.7 Ým) and broadband (0.3-2.8 Ým) spectral regions using vertically stacked multiple light weight autonomous unmanned aerial vehicles (UAVs) during the Maldives autonomous UAV campaign (MAC). The UAVs and ground based remote sensing instruments determined most of the parameters required for calculating the albedo and vertical distribution of solar fluxes. Measured fluxes have been compared with those derived from a Monte-Carlo radiative transfer algorithm which can incorporate both gaseous and aerosol components. The analysis focuses on a cloud-free day when the air was polluted due to long range transport from India, and the mean aerosol optical depth (AOD) was 0.31 and mean single scattering albedo was 0.92. The UAV measured absorption AOD was 0.019 which agreed within 20% of the value of 0.024 reported by a ground based instrument. The observed and simulated solar absorption agreed within 5% above 1.0 km and aerosol absorption accounted for 30% to 50% of the absorption depending upon the altitude and solar zenith angle. Thus there was no need to invoke anomalous or excess absorption or unknown physics in clear skies, provided we account for aerosol black carbon. The diurnal mean absorption values for altitudes between 0.5 and 3.0 km msl were observed to be 41¡Ó3 Wm-2 (1.5 K/day) in the broadband region and 8¡Ó2 Wm-2 (0.3 K/day) in the visible region. Future investigations into the atmospheric absorption in cloudy skies will characterize the spatial and temporal variation of the cloudy atmosphere in sufficient detail to simulate the vertical distribution of net solar fluxes to permit comparison with the collected radiative observations. This next phase will utilize 4 stacked UAVs to observe the extended cloud decks off the coast of California. A combination of observations and models will then be used to assess if the amount of solar absorption

  1. Haze in Pluto's Atmosphere: Implications for Processes and Evolution

    NASA Astrophysics Data System (ADS)

    Cheng, Andrew F.; Summers, Michael; Gladstone, Randy; Strobel, Darrell F.; Young, Leslie; Lavvas, Panayotis; Kammer, Joshua A.; Lisse, Casey M.; Parker, Alex Harrison; Young, Eliot F.; Stern, S. Alan; Weaver, Harold A.; Olkin, Catherine B.; Ennico, Kimberly

    2016-10-01

    Haze in Pluto's atmosphere was detected by New Horizons imaging to altitudes above 200 km at solar phase angles from ~20° to ~169°, and it was detected by the UV solar occultation up to 300 km altitude. The haze is strongly forward scattering in the visible, and a microphysical model of haze reproduces the visible phase function just above the surface with 0.5 µm spherical particles, but also invokes fractal aggregate particles to fit the visible phase function at 45 km altitude and to account for UV extinction. The visible phase function at the bottom of the atmosphere has a back scatter lobe which is absent from the phase function measured 45 km above the surface, making the latter phase function similar to that for haze in Titan's upper atmosphere. Pluto's haze is found at altitudes where direct condensation is not possible, but the haze may form by similar processes to those responsible for the detached haze layer in the upper atmosphere of Titan. It is suggested that haze particles form fractal aggregates which grow larger and more spherical as they settle downwards through the bottom 15 km of the atmosphere. Haze particles settle onto Pluto's surface, at a rate sufficient to alter surface optical properties on seasonal (hundred-year) time scales. However, if this picture applies to Pluto's atmosphere throughout the Pluto year, then haze particles would rapidly accumulate to an optically thick surface layer within thousands of years. These particles would not be processed into tholins except by cosmic rays, and the striking albedo contrasts on Pluto, with very bright and dark regions, would be difficult to understand. Pluto's regional scale albedo contrasts may be preserved by atmospheric collapse.

  2. Solar winds surfs waves in the Sun's atmosphere!

    NASA Astrophysics Data System (ADS)

    1999-06-01

    The fact that this electrified plasma speeds up to almost 3 million kilometres per hour as it leaves the Sun - twice as fast as originally predicted - has been known for years. The interpretation of how it happens is the real and surprising novelty: "The waves in the Sun's atmosphere are produced by vibrating solar magnetic field lines, which give solar wind particles a push just like an ocean wave gives a surfer a ride" said Dr John Kohl, principal investigator for the Ultraviolet Coronal Spectrometer (UVCS) - the instrument among the 12 aboard SOHO which gathered the data - and for the Spartan 201 mission. The outermost solar atmosphere, or corona, is only seen from Earth during a total eclipse of the Sun, when it appears as a shimmering, white veil surrounding the black lunar disc. The corona is an extremely tenuous, electrically charged gas, known as plasma, that flows throughout the solar system as the solar wind. The waves are formed by rapidly vibrating magnetic fields in the coronal plasma. They are called magneto - hydro - dynamic (MHD) waves and are believed to accelerate the solar wind. The solar wind is made up of electrons and ions, electrically charged atoms that have lost electrons. The electric charge of the solar wind particles forces them to travel along invisible lines of magnetic force in the corona. The particles spiral around the magnetic field lines as they rush into space. "The magnetic field acts like a violin string: when it's touched, it vibrates. When the Sun's magnetic field vibrates with a frequency equal to that of the particle spiraling around the magnetic field, it heats it up, producing a force that accelerates the particle upward and away from the Sun," says Dr. Ester Antonucci, an astronomer at the observatory of Turin, Italy, and co-investigator for SOHO's UVCS an instrument developed with considerable financial support by the Italian Space Agency, ASI. In a way this is similar to what happens if two people hold a string at

  3. Solar winds surfs waves in the Sun's atmosphere!

    NASA Astrophysics Data System (ADS)

    1999-07-01

    The fact that this electrified plasma speeds up to almost 3 million kilometres per hour as it leaves the Sun - twice as fast as originally predicted - has been known for years. The interpretation of how it happens is the real and surprising novelty: "The waves in the Sun's atmosphere are produced by vibrating solar magnetic field lines, which give solar wind particles a push just like an ocean wave gives a surfer a ride" said Dr John Kohl, principal investigator for the Ultraviolet Coronal Spectrometer (UVCS) - the instrument among the 12 aboard SOHO which gathered the data - and for the Spartan 201 mission. The outermost solar atmosphere, or corona, is only seen from Earth during a total eclipse of the Sun, when it appears as a shimmering, white veil surrounding the black lunar disc. The corona is an extremely tenuous, electrically charged gas, known as plasma, that flows throughout the solar system as the solar wind. The waves are formed by rapidly vibrating magnetic fields in the coronal plasma. They are called magneto - hydro - dynamic (MHD) waves and are believed to accelerate the solar wind. The solar wind is made up of electrons and ions, electrically charged atoms that have lost electrons. The electric charge of the solar wind particles forces them to travel along invisible lines of magnetic force in the corona. The particles spiral around the magnetic field lines as they rush into space. "The magnetic field acts like a violin string: when it's touched, it vibrates. When the Sun's magnetic field vibrates with a frequency equal to that of the particle spiraling around the magnetic field, it heats it up, producing a force that accelerates the particle upward and away from the Sun," says Dr. Ester Antonucci, an astronomer at the observatory of Turin, Italy, and co-investigator for SOHO's UVCS an instrument developed with considerable financial support by the Italian Space Agency, ASI. In a way this is similar to what happens if two people hold a string at

  4. Solar wind sputtering effects in the Martian atmosphere

    NASA Technical Reports Server (NTRS)

    Watson, C. C.; Haff, P. K.; Kellogg, W. K.

    1979-01-01

    A Monte Carlo simulation of the sputtering of the upper atmosphere of Mars by the solar wind was performed. The calculated sputtering yields imply loss rates (molecules/cm square - sec escaping the planet) for carbon dioxide, carbon, and oxygen of R(CO2) = 2.6 X 1000000/cm square - sec, R(C) = 6.6 X 1000000/cm square - sec, and R(O) = 7.7 X 1000000/cm - sec. The total mass loss by sputtering is only about 10% of that due to chemical and photo-chemical processes, but sputtering provides a major exospheric sink for carbon. The erosion process described here preferentially removes the lighter components of the atmosphere. Calculations based on a Monte Carlo simulation suggest that for a model atmosphere, 97% of the N2 and 33% of the CO2 originally present may have been sputtered away over 4.5 X 10 to the 9th power y. In the same length of time the (15)N/(14)N isotopic ratio for the bulk atmosphere would have increased by a factor 1.7.

  5. Global Forces in Eruptive Solar Flares: The Lorentz Force Acting on the Solar Atmosphere and the Solar Interior

    NASA Astrophysics Data System (ADS)

    Fisher, G. H.; Bercik, D. J.; Welsch, B. T.; Hudson, H. S.

    2012-03-01

    We compute the change in the Lorentz force integrated over the outer solar atmosphere implied by observed changes in vector magnetograms that occur during large, eruptive solar flares. This force perturbation should be balanced by an equal and opposite force perturbation acting on the solar photosphere and solar interior. The resulting expression for the estimated force change in the solar interior generalizes the earlier expression presented by Hudson, Fisher, and Welsch ( Astron. Soc. Pac. CS-383, 221, 2008), providing horizontal as well as vertical force components, and provides a more accurate result for the vertical component of the perturbed force. We show that magnetic eruptions should result in the magnetic field at the photosphere becoming more horizontal, and hence should result in a downward (toward the solar interior) force change acting on the photosphere and solar interior, as recently argued from an analysis of magnetogram data by Wang and Liu ( Astrophys. J. Lett. 716, L195, 2010). We suggest the existence of an observational relationship between the force change computed from changes in the vector magnetograms, the outward momentum carried by the ejecta from the flare, and the properties of the helioseismic disturbance driven by the downward force change. We use the impulse driven by the Lorentz-force change in the outer solar atmosphere to derive an upper limit to the mass of erupting plasma that can escape from the Sun. Finally, we compare the expected Lorentz-force change at the photosphere with simple estimates from flare-driven gasdynamic disturbances and from an estimate of the perturbed pressure from radiative backwarming of the photosphere in flaring conditions.

  6. Correlation of solar irradiance and atmospheric temperature variations derived from spacecraft radiometry

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Bolden, William C.; Gibson, M. A.; Paden, Jack; Pandey, Dhirendra K.; Thomas, Susan; Wilson, Robert S.

    1992-01-01

    Long-term changes in the mean global atmospheric temperature and the total solar irradiance were examined utilizing 1979-1989 spacecraft measurements. Outgoing longwave radiation at the top of the atmosphere was employed to infer global atmospheric temperatures. Evidence was determined that indicates the global temperatures should decline in the 1990-1997 period as the magnitude of the incoming solar irradiance declines with decreasing solar magnetic activity.

  7. Influences of atmospheric conditions and air mass on the ratio of ultraviolet to total solar radiation

    SciTech Connect

    Riordan, C.J.; Hulstrom, R.L.; Myers, D.R.

    1990-08-01

    The technology to detoxify hazardous wastes using ultraviolet (UV) solar radiation is being investigated by the DOE/SERI Solar Thermal Technology Program. One of the elements of the technology evaluation is the assessment and characterization of UV solar radiation resources available for detoxification processes. This report describes the major atmospheric variables that determine the amount of UV solar radiation at the earth's surface, and how the ratio of UV-to-total solar radiation varies with atmospheric conditions. These ratios are calculated from broadband and spectral solar radiation measurements acquired at SERI, and obtained from the literature on modeled and measured UV solar radiation. The following sections discuss the atmospheric effects on UV solar radiation and provide UV-to-total solar radiation ratios from published studies, as well as measured values from SERI's data. A summary and conclusions are also given.

  8. Io's fast sodium: Implications for molecular and atomic atmospheric escape

    NASA Technical Reports Server (NTRS)

    Wilson, Jody K.; Schneider, Nicholas M.

    1994-01-01

    Recent observational evidence for sodium-bearing molecular ions in the Io plasma torus has strong implications for the nature of Io's atmosphere (Schneider et al. 1991). We use a Monte Carlo model offast-sodium production to analyze high-resolution ground-based images of sodium emission. We find the observations can be explained if a significant fraction of Io's exobase is molecular, possible including a sodium-bearing molecule, Total sodium loss rates from Io imply a collisionally thick atmosphere. Most of the images indicate significant slow-down of the corotating plasma near Io.

  9. Terminology of Large-Scale Waves in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Vršnak, Bojan

    2005-03-01

    This is the fourth in a series of essays on terms used in solar-terrestrial physics that are thought to be in need of clarification. Terms are identified and essays are commissioned by a committee chartered by Division II (Sun and Heliosphere) of the International Astronomical Union. Terminology Committee members include Ed Cliver (chair), Jean-Louis Bougeret, Hilary Cane, Takeo Kosugi, Sara Martin, Rainer Schwenn, and Lidia van Driel-Gestelyi. Authors are asked to review the origins of terms and their current usage/misusage. The goals are to inform the community and to open a discussion. The following article by Bojan Vršnak focuses on terms used to describe large-scale waves in the solar atmosphere, an area of research that has been given great impetus by the images of waves from the Extreme ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO). The committee welcomes suggestions for other terms to address in this forum.

  10. Alfvén waves in the lower solar atmosphere.

    PubMed

    Jess, David B; Mathioudakis, Mihalis; Erdélyi, Robert; Crockett, Philip J; Keenan, Francis P; Christian, Damian J

    2009-03-20

    The flow of energy through the solar atmosphere and the heating of the Sun's outer regions are still not understood. Here, we report the detection of oscillatory phenomena associated with a large bright-point group that is 430,000 square kilometers in area and located near the solar disk center. Wavelet analysis reveals full-width half-maximum oscillations with periodicities ranging from 126 to 700 seconds originating above the bright point and significance levels exceeding 99%. These oscillations, 2.6 kilometers per second in amplitude, are coupled with chromospheric line-of-sight Doppler velocities with an average blue shift of 23 kilometers per second. A lack of cospatial intensity oscillations and transversal displacements rules out the presence of magneto-acoustic wave modes. The oscillations are a signature of Alfvén waves produced by a torsional twist of +/-22 degrees. A phase shift of 180 degrees across the diameter of the bright point suggests that these torsional Alfvén oscillations are induced globally throughout the entire brightening. The energy flux associated with this wave mode is sufficient to heat the solar corona.

  11. The Influence of Solar Proton Events in Solar Cycle 23 on the Neutral Middle Atmosphere

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; vonKonig, Miriam; Anderson, John; Roble, Raymond G.; McPeters, Richard D.; Fleming, Eric L.; Russell, James M.

    2004-01-01

    Solar proton events (SPEs) can cause changes in constituents in the Earth's middle atmosphere. The highly energetic protons cause ionizations, excitations, dissociations, and dissociative ionizations of the background constituents, which lead to the production of HO(x) (H, OH, HO2) and NO(y) (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2). The HO(x) increases lead to short-lived ozone decreases in the mesosphere and upper stratosphere due to the short lifetimes of the HO, constituents. The NO(x) increases lead to long-lived stratospheric ozone changes because of the long lifetime of NO(y) constituents in this region. Solar cycle 23 was quite active with SPEs and very large fluxes of high energy protons occurred in July and November 2000, November 200 1, and April 2002. Smaller, but still substantial, proton fluxes impacted the Earth during other months in the 1997-2003 time period. The impact of the very large SPEs on the neutral middle atmosphere during solar cycle 23 will be discussed, including the HO(x), NO(y), ozone variations and induced atmospheric transport changes. Two multi-dimensional models, the Goddard Space Flight Center (GSFC) Two-dimensional (2D) Model and the Thermosphere Ionosphere Mesosphere Electrodynamic General Circulation Model (TIME-GCM), were used in computing the influence of the SPEs. The results of the GSFC 2D Model and the TIME-GCM will be shown along with comparisons to the Upper Atmosphere Research Satellite (UARS) Halogen Occultation Experiment (HALOE) and Solar Backscatter Ultraviolet 2 (SBUV/2) instruments.

  12. Influence of Solar Proton Events on the Middle Atmosphere

    NASA Astrophysics Data System (ADS)

    Kilifarska, Nataliya

    Do particle precipitations during solar proton events really affect the chemical and thermodynamical state of the middle atmosphere? - is still an open question. This study investigates the changes in the ozone mixing ratio, temperature and wind profiles during and immediately after solar proton event on 20 January 2005. Analysis is based on the data from Microwave Limb Sounder (MLS) on board the AURA satellite, GOES 11 satellite and ground based radiosondes measurements. MLS data for ozone, temperature and pressure profiles - taken at 500 N, within the longitudinal range of 0.2÷400 E - are compared with radiosondes measurements from several stations within the same region. We select six energy intervals for proton fluxes measured on GOES 11 (E=0.8 - 4 MeV, E=9 - 15 MeV, E=15 - 40 MeV, E=40 - 80 MeV, E=80 - 165 MeV and E=165 - 500 MeV) and analyzed their effect on the ozone mixing ratio and temperature at seven atmospheric levels (15.45 ˆ` 18.54 ˆ` 24.72 ˆ` 30.90 ˆ` 37.08 ˆ` eı, eı, eı, eı, eı, 43.26 ˆ` and 46.35 km). eı Ozone and temperature at each level are regressed onto all energetic proton bands, solar activity and atmospheric indexes QBO (quasibiennial oscillations) and AO (arctic oscillations), characterizing the background atmospheric conditions. Preliminary analysis shows that the effectiveness of the low energetic protons for enhancement of ozone in the whole middle and low stratosphere is much greater than those of high energetic, but with low intensity, protons. Temperature response on the increased particle precipitation is positive in the middle stratosphere and negative in the lower stratosphere. The temperatures increase in the middle stratosphere possibly due to the O3 heating effect at these altitudes, because it almost exactly coincides with ozone enhancement layer. The depletion of the temperature into the lower stratosphere may be related to the shielding effect of the enhanced O3 mixing ratio in the upper levels.

  13. The Atmospheric Imaging Assembly on the Solar Dynamics Observatory

    NASA Astrophysics Data System (ADS)

    Title, Alan M.; AIA Team

    2006-06-01

    The Atmospheric Imaging Assembly (AIA) on SDO will provide revolutionary coverage of the entire visible solar hemisphere, observed from photospheric to coronal temperatures, at 1-arcsecond resolution, with a characteristic cadence of 10 seconds for each channel. The AIA comprises four dual normal-incidence telescopes that enable it to cycle through a set of EUV channels centered on strong emission lines of iron (ranging from Fe IX through XXIII) and helium (304A), plus two UV channels near 1600A and a broad band visible channel. Combined with the (vector-)magnetic imagery from SDO/HMI, the AIA observations will significantly further our understanding of the dynamics of the magnetic field in the solar atmosphere and heliosphere, both in quiescent and eruptive stages. The comprehensive thermal coverage of the corona will open new avenues of study for coronal energetics and seismology, which will benefit from the excellent calibration against the SDO/EVE spectral irradiance measurements. The AIA data will be easily accessible on the web, with a time delay that is expected to be of the order of 15 minutes to 1 hour. Users will be able to browse the data through summary web pages that are complemented by a comprehensive metadata catalog. Data analysis will be supported through the freely available SolarSoft libraries and through modules in a flexible, evolving pipeline data analysis system to be operated at the AIA-HMI Joint Science Operations Center. We plan to incorporate feature recognition software, automated movie making, coronal field modeling, and other supporting analysis software. We invite the broad ILWS community to contact us with ideas to collaborate on any aspect of the AIA Investigation. Details on the AIA instrument, the Science Investigation, and related news can be found at http://aia.lmsal.com.

  14. Waves and Magnetism in the Solar Atmosphere (WAMIS)

    NASA Astrophysics Data System (ADS)

    Ko, Yuan-Kuen; Moses, John; Laming, John; Strachan, Leonard; Tun Beltran, Samuel; Tomczyk, Steven; Gibson, Sarah; Auchere, Frederic; Casini, Roberto; Fineschi, Silvano; Knoelker, Michael; Korendyke, Clarence; McIntosh, Scott; Romoli, Marco; Rybak, Jan; Socker, Dennis; Vourlidas, Angelos; Wu, Qian

    2016-02-01

    Comprehensive measurements of magnetic fields in the solar corona have a long history as an important scientific goal. Besides being crucial to understanding coronal structures and the Sun’s generation of space weather, direct measurements of their strength and direction are also crucial steps in understanding observed wave motions. In this regard, the remote sensing instrumentation used to make coronal magnetic field measurements is well suited to measuring the Doppler signature of waves in the solar structures. In this paper, we describe the design and scientific values of the Waves and Magnetism in the Solar Atmosphere (WAMIS) investigation. WAMIS, taking advantage of greatly improved infrared filters and detectors, forward models, advanced diagnostic tools and inversion codes, is a long-duration high-altitude balloon payload designed to obtain a breakthrough in the measurement of coronal magnetic fields and in advancing the understanding of the interaction of these fields with space plasmas. It consists of a 20 cm aperture coronagraph with a visible-IR spectro-polarimeter focal plane assembly. The balloon altitude would provide minimum sky background and atmospheric scattering at the wavelengths in which these observations are made. It would also enable continuous measurements of the strength and direction of coronal magnetic fields without interruptions from the day-night cycle and weather. These measurements will be made over a large field-of-view allowing one to distinguish the magnetic signatures of different coronal structures, and at the spatial and temporal resolutions required to address outstanding problems in coronal physics. Additionally, WAMIS could obtain near simultaneous observations of the electron scattered K-corona for context and to obtain the electron density. These comprehensive observations are not provided by any current single ground-based or space observatory. The fundamental advancements achieved by the near-space observations of

  15. A Probable Approx. 2400 Year Solar Quasi-cycle in Atmospheric Delta C-14

    NASA Technical Reports Server (NTRS)

    Hood, L. L.; Jirikowic, J. L.

    1990-01-01

    A 2200 to 2600 year quasi-periodicity is present in atmospheric delta C-14 records after removal of long-term trends due to the geomagnetic dipole amplitude variation. This periodicity consists of both a long-term variation of the mean and a superposed, approximately recurring pattern of century-scale variations. The strongest of these latter variations occur near maxima of the approx. 2400 year delta C-14 cycles. The residual record can be modeled to first order as an amplitude modulation of a century-scale periodic forcing function by a approx. 2400 year periodic forcing function. During the last millennium, the largest century-scale variations (occurring near the most recent 2400 year delta C-14 maximum) are known to be mainly a consequence of the pronounced Maunder, Sporer, and Wolf solar activity minima, as verified by independent proxy solar activity records. Therefore, during this period, amplitude modulation has been occurring primarily in the sun and not in the terrestrial radiocarbon system. It is therefore inferred that the approx. 2400 year forcing function is mainly solar although some secondary terrestrial feedback into the delta C-14 record is likely. This conclusion has implications for the predictability of future pronounced solar activity minima and for the interpretation of certain minor Holocene climatic variations.

  16. Satellite Measurements of Middle Atmospheric Impacts by Solar Proton Events in Solar Cycle 23

    NASA Technical Reports Server (NTRS)

    Jackman, C.; Labow, G.; DeLand, M.; Fleming, E.; Sinnhuber, M.; Russell, J.

    2005-01-01

    Solar proton events (SPEs) are known to have caused changes in constituents in the Earth's neutral polar middle atmosphere in the most recent solar maximum period (solar cycle 23). The highly energetic protons produced ionizations, excitations, dissociations, and dissociative ionizations of the background constituents in the polar cap regions (greater than 60 degrees geomagnetic latitude), which led to the production of HOx (H, OH, HO2) and NOy (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2). The HOx increases led to short-lived ozone decreases in the polar mesosphere and upper stratosphere due to the short lifetimes of the HOx constituents. Polar middle mesospheric ozone decreases greater than 50% were observed and computed to last for hours to days due to the enhanced HOx. The NOy increases led to long-lived polar stratospheric ozone changes because of the long lifetime of the NOy family in this region. Upper stratospheric ozone decreases of greater than 10% were computed to last for several months past the solar events in the winter polar regions because of the enhanced NOy. Solar cycle 23 was especially replete with SPEs and huge fluxes of high energy protons occurred in July and November 2000, September and November 2001, April 2002, October 2003, and January 2005. Smaller, but still substantial, proton fluxes impacted the Earth during other months in this cycle. Observations by the Upper Atmosphere Research Satellite (UARS) Halogen Occultation Experiment (HALOE) and Solar Backscatter Ultraviolet 2 (SBUV/2) instruments along with GSFC 2D Model predictions will be shown in this talk.

  17. Origin and stability of exomoon atmospheres: implications for habitability.

    PubMed

    Lammer, Helmut; Schiefer, Sonja-Charlotte; Juvan, Ines; Odert, Petra; Erkaev, Nikolai V; Weber, Christof; Kislyakova, Kristina G; Güdel, Manuel; Kirchengast, Gottfried; Hanslmeier, Arnold

    2014-09-01

    We study the origin and escape of catastrophically outgassed volatiles (H2O, CO2) from exomoons with Earth-like densities and masses of 0.1, 0.5 and 1 M⊕ orbiting an extra-solar gas giant inside the habitable zone of a young active solar-like star. We apply a radiation absorption and hydrodynamic upper atmosphere model to the three studied exomoon cases. We model the escape of hydrogen and dragged dissociation products O and C during the activity saturation phase of the young host star. Because the soft X-ray and EUV radiation of the young host star may be up to ~100 times higher compared to today's solar value during the first 100 Myr after the system's origin, an exomoon with a mass < 0.25 M⊕ located in the HZ may not be able to keep an atmosphere because of its low gravity. Depending on the spectral type and XUV activity evolution of the host star, exomoons with masses between ~0.25 and 0.5 M⊕ may evolve to Mars-like habitats. More massive bodies with masses >0.5 M⊕, however, may evolve to habitats that are a mixture of Mars-like and Earth-analogue habitats, so that life may originate and evolve at the exomoon's surface.

  18. The Pechora River Runoff, Atmospheric Circulation and Solar Activity

    NASA Astrophysics Data System (ADS)

    Golovanov, O. F.

    This study presents an attempt to define and estimate the factors effecting and possi- bly, determining the spatial-temporal characteristics of the Pechora River hydrological regime. The time-series of hydrometeorological observations (runoff, precipitation, air temperature) carried out within the basin of the impact object U the Pechora River U are close to secular and include the year of the century maximum of the solar activ- ity (1957). The joint statistical analysis of these characteristics averaged both for a year and for the low water periods in spring (V-VII), summer-autumn (VIII-IX) and winter (X-IV) demonstrated the majority of integral curves to have minimums coin- ciding or slightly differing from the solar activity maximum in 1957. It is especially typical for the spring high water runoff along the entire length of the Pechora River. Only the curves of the air temperature in the summer-autumn low water period are in the opposite phase relative to all other elements. In the upper Pechora the inte- gral curves of winter and annual precipitation are synchronous to the runoff curves. The multiyear variability of the Pechora runoff corresponds to that of the atmospheric circulation in the northern hemisphere. This is clearly illustrated by the decrease of the Pechora runoff and increase of the climate continentality in its basin, that is ac- companied with predominating of the meridional circulation, anticyclone invasion and precipitation decrease while the solar activity grows. This process takes place at the background of the prevailing mass transport of E+C type, increase of number of the elementary synoptic processes (ESP). The maximum number of ESP (observed in 1963) was recorded soon after the century maximum of the solar activity. This fact may be explained by the anticyclone circulation prevalence which results in growth of the climate continentality in the Pechora basin in this period. The enumerated in- flection points of the integral curves of

  19. ON THE COMBINATION OF IMAGING-POLARIMETRY WITH SPECTROPOLARIMETRY OF UPPER SOLAR ATMOSPHERES DURING SOLAR ECLIPSES

    SciTech Connect

    Qu, Z. Q.; Deng, L. H.; Dun, G. T.; Chang, L.; Zhang, X. Y.; Cheng, X. M.; Qu, Z. N.; Xue, Z. K.; Ma, L.; Allington-Smith, J.; Murray, G.

    2013-09-01

    We present results from imaging polarimetry (IP) of upper solar atmospheres during a total solar eclipse on 2012 November 13 and spectropolarimetry of an annular solar eclipse on 2010 January 15. This combination of techniques provides both the synoptic spatial distribution of polarization above the solar limb and spectral information on the physical mechanism producing the polarization. Using these techniques together we demonstrate that even in the transition region, the linear polarization increases with height and can exceed 20%. IP shows a relatively smooth background distribution in terms of the amplitude and direction modified by solar structures above the limb. A map of a new quantity that reflects direction departure from the background polarization supplies an effective technique to improve the contrast of this fine structure. Spectral polarimetry shows that the relative contribution to the integrated polarization over the observed passband from the spectral lines decreases with height while the contribution from the continuum increases as a general trend. We conclude that both imaging and spectral polarimetry obtained simultaneously over matched spatial and spectral domains will be fruitful for future eclipse observations.

  20. Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures.

    PubMed

    Stüeken, E E; Kipp, M A; Koehler, M C; Schwieterman, E W; Johnson, B; Buick, R

    2016-12-01

    Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this reservoir may have fluctuated significantly over the course of Earth's history with particularly low levels in the Neoarchean-presumably as a result of biological activity. We used a biogeochemical box model to test which conditions are necessary to cause large swings in atmospheric N2 pressure. Parameters for our model are constrained by observations of modern Earth and reconstructions of biomass burial and oxidative weathering in deep time. A 1-D climate model was used to model potential effects on atmospheric climate. In a second set of tests, we perturbed our box model to investigate which parameters have the greatest impact on the evolution of atmospheric pN2 and consider possible implications for nitrogen cycling on other planets. Our results suggest that (a) a high rate of biomass burial would have been needed in the Archean to draw down atmospheric pN2 to less than half modern levels, (b) the resulting effect on temperature could probably have been compensated by increasing solar luminosity and a mild increase in pCO2, and (c) atmospheric oxygenation could have initiated a stepwise pN2 rebound through oxidative weathering. In general, life appears to be necessary for significant atmospheric pN2 swings on Earth-like planets. Our results further support the idea that an exoplanetary atmosphere rich in both N2 and O2 is a signature of an oxygen-producing biosphere. Key Words: Biosignatures-Early Earth-Planetary atmospheres. Astrobiology 16, 949-963.

  1. Solar Wind Interaction and Impact on the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Futaana, Yoshifumi; Stenberg Wieser, Gabriella; Barabash, Stas; Luhmann, Janet G.

    2017-08-01

    Venus has intrigued planetary scientists for decades because of its huge contrasts to Earth, in spite of its nickname of "Earth's Twin". Its invisible upper atmosphere and space environment are also part of the larger story of Venus and its evolution. In 60s to 70s, several missions (Venera and Mariner series) explored Venus-solar wind interaction regions. They identified the basic structure of the near-Venus space environment, for example, existence of the bow shock, magnetotail, ionosphere, as well as the lack of the intrinsic magnetic field. A huge leap in knowledge about the solar wind interaction with Venus was made possible by the 14-year long mission, Pioneer Venus Orbiter (PVO), launched in 1978. More recently, ESA's probe, Venus Express (VEX), was inserted into orbit in 2006, operated for 8 years. Owing to its different orbit from that of PVO, VEX made unique measurements in the polar and terminator regions, and probed the near-Venus tail for the first time. The near-tail hosts dynamic processes that lead to plasma energization. These processes in turn lead to the loss of ionospheric ions to space, slowly eroding the Venusian atmosphere. VEX carried an ion spectrometer with a moderate mass-separation capability and the observed ratio of the escaping hydrogen and oxygen ions in the wake indicates the stoichiometric loss of water from Venus. The structure and dynamics of the induced magnetosphere depends on the prevailing solar wind conditions. VEX studied the response of the magnetospheric system on different time scales. A plethora of waves was identified by the magnetometer on VEX; some of them were not previously observed by PVO. Proton cyclotron waves were seen far upstream of the bow shock, mirror mode waves were observed in magnetosheath and whistler mode waves, possibly generated by lightning discharges were frequently seen. VEX also encouraged renewed numerical modeling efforts, including fluid-type of models and particle-fluid hybrid type of models

  2. Solar wind interaction with the Martian upper atmosphere: Crustal field orientation, solar cycle, and seasonal variations

    NASA Astrophysics Data System (ADS)

    Dong, Chuanfei; Bougher, Stephen W.; Ma, Yingjuan; Toth, Gabor; Lee, Yuni; Nagy, Andrew F.; Tenishev, Valeriy; Pawlowski, Dave J.; Combi, Michael R.; Najib, Dalal

    2015-09-01

    A comprehensive study of the solar wind interaction with the Martian upper atmosphere is presented. Three global models: the 3-D Mars multifluid Block Adaptive Tree Solar-wind Roe Upwind Scheme MHD code (MF-MHD), the 3-D Mars Global Ionosphere Thermosphere Model (M-GITM), and the Mars exosphere Monte Carlo model Adaptive Mesh Particle Simulator (M-AMPS) were used in this study. These models are one-way coupled; i.e., the MF-MHD model uses the 3-D neutral inputs from M-GITM and the 3-D hot oxygen corona distribution from M-AMPS. By adopting this one-way coupling approach, the Martian upper atmosphere ion escape rates are investigated in detail with the combined variations of crustal field orientation, solar cycle, and Martian seasonal conditions. The calculated ion escape rates are compared with Mars Express observational data and show reasonable agreement. The variations in solar cycles and seasons can affect the ion loss by a factor of ˜3.3 and ˜1.3, respectively. The crustal magnetic field has a shielding effect to protect Mars from solar wind interaction, and this effect is the strongest for perihelion conditions, with the crustal field facing the Sun. Furthermore, the fraction of cold escaping heavy ionospheric molecular ions [(O2+ and/or O2+)/Total] are inversely proportional to the fraction of the escaping (ionospheric and corona) atomic ion [O+/Total], whereas O2+ and O2+ ion escape fractions show a positive linear correlation since both ion species are ionospheric ions that follow the same escaping path.

  3. Detailed and simplified nonequilibrium helium ionization in the solar atmosphere

    SciTech Connect

    Golding, Thomas Peter; Carlsson, Mats; Leenaarts, Jorrit E-mail: mats.carlsson@astro.uio.no

    2014-03-20

    Helium ionization plays an important role in the energy balance of the upper chromosphere and transition region. Helium spectral lines are also often used as diagnostics of these regions. We carry out one-dimensional radiation-hydrodynamics simulations of the solar atmosphere and find that the helium ionization is set mostly by photoionization and direct collisional ionization, counteracted by radiative recombination cascades. By introducing an additional recombination rate mimicking the recombination cascades, we construct a simplified three-level helium model atom consisting of only the ground states. This model atom is suitable for modeling nonequilibrium helium ionization in three-dimensional numerical models. We perform a brief investigation of the formation of the He I 10830 and He II 304 spectral lines. Both lines show nonequilibrium features that are not recovered with statistical equilibrium models, and caution should therefore be exercised when such models are used as a basis for interpretating observations.

  4. Detailed and Simplified Nonequilibrium Helium Ionization in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Golding, Thomas Peter; Carlsson, Mats; Leenaarts, Jorrit

    2014-03-01

    Helium ionization plays an important role in the energy balance of the upper chromosphere and transition region. Helium spectral lines are also often used as diagnostics of these regions. We carry out one-dimensional radiation-hydrodynamics simulations of the solar atmosphere and find that the helium ionization is set mostly by photoionization and direct collisional ionization, counteracted by radiative recombination cascades. By introducing an additional recombination rate mimicking the recombination cascades, we construct a simplified three-level helium model atom consisting of only the ground states. This model atom is suitable for modeling nonequilibrium helium ionization in three-dimensional numerical models. We perform a brief investigation of the formation of the He I 10830 and He II 304 spectral lines. Both lines show nonequilibrium features that are not recovered with statistical equilibrium models, and caution should therefore be exercised when such models are used as a basis for interpretating observations.

  5. Minimal seesaw model for atmospheric and solar neutrino oscillations

    SciTech Connect

    Ma, E.; Roy, D.P. |

    1999-05-01

    We present a minimal seesaw model based on an extension of the standard model (SM) which includes an additional U(1), with gauge charge B{minus} (3) /(2) (L{sub {mu}}+L{sub {tau}}). The requirement of anomaly cancellation implies the existence of two right-handed singlet neutrinos, carrying this gauge charge, which have normal Dirac couplings to {nu}{sub {mu}} and {nu}{sub {tau}} but suppressed ones to {nu}{sub e}. Assuming the U(1) symmetry breaking scale to be 10{sup 12}{minus}10{sup 16} GeV, this model can naturally account for the large (small) mixing solutions to the atmospheric (solar) neutrino oscillations. {copyright} {ital 1999} {ital The American Physical Society}

  6. Spectropolarimetry of fine magnetized structures in the upper solar atmosphere

    NASA Astrophysics Data System (ADS)

    Schad, Thomas Anthony

    2013-12-01

    One of the earliest indications of magnetic fields acting in the solar atmosphere came at the beginning of the 20th century when George Hale noted a "decided definiteness of structure" in photographs within the Hydrogen Balmer-alpha line core. Fine structure both in the chromosphere and in the corona result from processes that are not well understood but accepted as a consequence of the solar magnetic field. Our knowledge of this field is lacking, and until recently, the assumed relationship between fine thermal structure and the magnetic field remained untested. Here, spectropolarimetric diagnostics of fine structures in the solar chromosphere and cool corona are advanced using the infrared He I triplet at 1083 nm. Precise calibration procedures are developed for the Facility Infrared Spectropolarimeter (FIRS), recently commissioned at the Dunn Solar Telescope. Together with high-order adaptive optics, we simultaneously map fine structures while obtaining a polarimetric sensitivity of up to 2 x 10--4 of the incoming intensity. These instrument improvements result in the first maps of the He I polarized signatures within an active region superpenumbra, where Hale first recognized fine-structuring. Selective absorption and emission processes due to non-equilibrium optical pumping are recognized. Our interpretation, using advanced inversions of the He I triplet, provides confirmation of Hale's initial suspicion---the fine structures of the solar chromosphere are visual markers for the magnetic field. Yet, the fine chromospheric thermal structure is not matched by an equivalently fine magnetic structure. Our ability to measure this field suggests the utility of the He I triplet as an inner boundary condition for the inner heliospheric magnetic field. In the corona itself, we infer the vector properties of a catastrophically-cooled coronal loop, uniting space-based and ground-based instrumentation. We determine how fine loops are anchored in the photosphere via a

  7. Impact of a total solar eclipse on surface atmospheric electricity

    NASA Astrophysics Data System (ADS)

    Manohar, G. K.; Kandalgaonkar, S. S.; Kulkarni, M. K.

    1995-10-01

    A study of the impact of a total solar eclipse (TSE) on surface atmospheric electricity was made using observations of surface electrical potential gradient, conductivity, and boundary layer parameters recorded during the TSE of February 16, 1980, and on a control day at Raichur. The study showed that with the progressing of the eclipse, as a consequence of inhibited convection, the responses of turbulent mixing in the boundary layer near the ground exhibited diminution and subsequent restoration, respectively. During the next 45 min after the totality, when the surface layer remained stably stratified, the diminution in the potential gradient and the increase in the conductivity was maximum; this was about 60% and 200%, respectively, of their corresponding control day values. This result is in very good agreement with most earlier studies of solar eclipses. The study of the impact of the TSE during 3-4 hours of posteclipse showed significant cooling (˜3°C) of the entire surface air layer and a considerable drop in wind speed over the stretch (1130 km×120 km) of the totality-occupied land region. This significant and systematic phenomenon was responsible for setting up a land-sea breezelike circulation, that is, subsidence/downward air motion over the totality-occupied land region and upward over the noneclipsed land across the totality stretch. This resulted in a considerable aerosol-induced reduction in conductivity and about 5 to 8 times increase in potential gradient during the 3-4 hours of posteclipse. This response of the atmospheric electricity parameters was unlike that observed on the normal days.

  8. Implications of the solar eclipse on the geomagnetic field

    NASA Astrophysics Data System (ADS)

    KIM, J. H.; Chang, H. Y.

    2016-12-01

    The solar eclipse, which is one of very rare natural phenomena, affects terrestrial environments in various aspects. For instance, it is well known that the electron concentration and current density decrease in the ionosphere due to the reduction of solar irradiation while the moon passed between the Earth and the Sun. Effects of the solar eclipse on the geomagnetic field profile, however, requires careful analysis. In this study, we carry out the statistical analysis of x, y, z, H-components, and the intensity of the geomagnetic field using the ground geomagnetic data observed during the solar eclipses from 1991 to 2016. We confirm that characteristic decreases in the x and H-components can be seen in the vicinity of the maximum eclipse time at the observing site. We find that the decrease in x and H-components is more conspicuous during the total solar eclipse rather than the partial or annular eclipses. We also find that such a dip is likely to be noticed when the observing site locates in the second half compared to the first half of the eclipse path, as well as when the eclipse occurs in dawn side than in dusk side. We have investigated any dependence on the solar cycle, and found that reductions in the ground geomagnetic field by the solar eclipse are more evident in the ascending phase of the solar cycle than in the descending phase. Finally, we briefly discuss implications of our findings.

  9. Thermal Mapping to Achieve 3-D Structure and Dynamics of Planetary Atmospheres Throughout the Solar System

    NASA Astrophysics Data System (ADS)

    Greathouse, T. K.; Retherford, K. D.; Mandt, K. E.; Wyrick, D. Y.

    2017-02-01

    We have completed our first look at all planets in the solar system. It is now time to move forward with more complete studies of solar system planetary atmospheres to further our understanding of atmospheric dynamics of planets unlike the Earth.

  10. Middle-atmosphere positive ion measurements during solar eclipses

    NASA Astrophysics Data System (ADS)

    Mitchell, J. D.

    1985-02-01

    Solar effects on middle-atmosphere electrical parameters, as demonstrated by eclipse-associated responses of conductivity, ion mobility, and charge density, are considered for the total solar eclipses at Red Lake, Ontario, Canada on February 26, 1979 and at San Marco range, Kenya, on February 16, 1980. Negative-conductivity measurements for the Canadian eclipse and probe-current measurements for the Kenyan eclipse demonstrate a rapid loss of free electrons below 80 km at totality. During the Kenyan eclipse, positive-ion responses were different for each of two distinct ion mobility groups. Between 45 and 60 km, eclipse-related positive-ion responses are associated with the low-mobility ions. It is shown that these ions are lost at totality and that an excess buildup occurs following totality. Above 70 km, positive-ion loss at totality is associated with the more mobile ions and only low-mobility positive ions are measured in this region. The buildup in total ion density following totality is thought to result from a reduction in ion loss associated with weak-electron recovery in the region.

  11. Middle-atmosphere positive ion measurements during solar eclipses

    NASA Technical Reports Server (NTRS)

    Mitchell, J. D.

    1985-01-01

    Solar effects on middle-atmosphere electrical parameters, as demonstrated by eclipse-associated responses of conductivity, ion mobility, and charge density, are considered for the total solar eclipses at Red Lake, Ontario, Canada on February 26, 1979 and at San Marco range, Kenya, on February 16, 1980. Negative-conductivity measurements for the Canadian eclipse and probe-current measurements for the Kenyan eclipse demonstrate a rapid loss of free electrons below 80 km at totality. During the Kenyan eclipse, positive-ion responses were different for each of two distinct ion mobility groups. Between 45 and 60 km, eclipse-related positive-ion responses are associated with the low-mobility ions. It is shown that these ions are lost at totality and that an excess buildup occurs following totality. Above 70 km, positive-ion loss at totality is associated with the more mobile ions and only low-mobility positive ions are measured in this region. The buildup in total ion density following totality is thought to result from a reduction in ion loss associated with weak-electron recovery in the region.

  12. On the efficiency of solar heating in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Solomon, Susan

    1991-01-01

    The efficiency at which solar ultraviolet radiation absorbed in the Hartley band of ozone is directly converted to heat in the terrestrial mesosphere and lower thermosphere (50-110 km) is calculated. The ozone molecule undergoes photolysis to yield the excited species O(1D) and O2(1Delta) with a quantum yield of about 0.9. Spontaneous emission from O2(1Delta) and from O2(1Sigma) (excited by energy transfer from O/1D/) significantly decreases the amount of energy available for heat. Similarly, the efficiency at which solar ultraviolet radiation absorbed by O2 in the Schumann-Runge continuum is directly converted to heat in the lower thermosphere (95-110 km) is calculated. The O2 undergoes photolysis and the excited product O(1D) is generated. Spontaneous emission from O2(1Sigma) (excited by energy transfer from O/1D/) reduces the amount of energy available for heat in the lower thermosphere. The consideration of these energy transfer and loss processes results in significantly reduced heating rates as compared to those conventionally calculated in models of the middle atmosphere.

  13. Saturn's microwave spectrum: Implications for the atmosphere and the rings

    NASA Technical Reports Server (NTRS)

    Klein, M. J.; Janssen, M. A.; Gulkis, S.; Olsen, E. T.

    1978-01-01

    Measurements of Saturn's disk temperature are compiled to determine the planet's microwave spectrum from 1 mm to 100 cm wavelength. The data were adjusted to conform with a common flux density scale. A model of Saturn's rings is used to remove the effects of the rings from the atmospheric component at centimeter and decimeter wavelengths. Theoretical spectra for a number of convective atmospheric models were computed and compared with the observed spectrum. Radiative-convective models with approximately solar composition and with an effective temperature of approximately 89 K are in good agreement with the observations. The agreement between the observed and theoretical spectra is a strong indication that gaseous ammonia is present in Saturn's atmosphere. A good fit to the data is obtained with an ammonia mixing ratio of approximately 5 x 10,0001. A comparison of the millimeter wavelength data with the best-fitting atmospheric spectrum indicates that the thermal component of the ring brightness temperature near 1 mm wavelength is approximately 25 k.

  14. Neutron and Proton Dosages in the Upper Atmosphere from Solar Flare Radiation.

    PubMed

    Flamm, E J; Lingenfelter, R E

    1964-06-26

    The radiation dosage from secondary neutrons as well as from primary and secondary protons in the earth's atmosphere during solar particle events is calculated as a function of the solar proton flux, atmospheric depth, and geomagnetic-cutoff rigidity. The dosage in rems from secondary neutrons exceeds the dosage from protons below 30 g/cm(2) of residual atmosphere. Neutron dosages in rads are less than the dosage from primary protons at all depths above 100 g/cm(2). The maximum neutron dose to travelers in supersonic aircraft during solar particle events of the magnitude observed during the last solar cycle would be of the order of I rem.

  15. Modeling of the atmospheric response to a strong decrease of the solar activity

    NASA Astrophysics Data System (ADS)

    Rozanov, Eugene V.; Egorova, Tatiana A.; Shapiro, Alexander I.; Schmutz, Werner K.

    2012-07-01

    We estimate the consequences of a potential strong decrease of the solar activity using the model simulations of the future driven by pure anthropogenic forcing as well as its combination with different solar activity related factors: total solar irradiance, spectral solar irradiance, energetic electron precipitation, solar protons and galactic cosmic rays. The comparison of the model simulations shows that introduced strong decrease of solar activity can lead to some delay of the ozone recovery and partially compensate greenhouse warming acting in the direction opposite to anthropogenic effects. The model results also show that all considered solar forcings are important in different atmospheric layers and geographical regions. However, in the global scale the solar irradiance variability can be considered as the most important solar forcing. The obtained results constitute probably the upper limit of the possible solar influence. Development of the better constrained set of future solar forcings is necessary to address the problem of future climate and ozone layer with more confidence.

  16. Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures

    NASA Astrophysics Data System (ADS)

    Stüeken, E. E.; Kipp, M. A.; Koehler, M. C.; Schwieterman, E. W.; Johnson, B.; Buick, R.

    2016-12-01

    Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this reservoir may have fluctuated significantly over the course of Earth's history with particularly low levels in the Neoarchean - presumably as a result of biological activity. We used a biogeochemical box model to test which conditions are necessary to cause large swings in atmospheric N2 pressure. Parameters for our model are constrained by observations of modern Earth and reconstructions of biomass burial and oxidative weathering in deep time. A 1-D climate model was used to model potential effects on atmospheric climate. In a second set of tests, we perturbed our box model to investigate which parameters have the greatest impact on the evolution of atmospheric pN2 and consider possible implications for nitrogen cycling on other planets. Our results suggest that (a) a high rate of biomass burial would have been needed in the Archean to draw down atmospheric pN2 to less than half modern levels, (b) the resulting effect on temperature could probably have been compensated by increasing solar luminosity and a mild increase in pCO2, and (c) atmospheric oxygenation could have initiated a stepwise pN2 rebound through oxidative weathering. In general, life appears to be necessary for significant atmospheric pN2 swings on Earth-like planets. Our results further support the idea that an exoplanetary atmosphere rich in both N2 and O2 is a signature of an oxygen-producing biosphere.

  17. The mechanism of temperature and pressure changes in the Earth's atmosphere during solar flares

    NASA Technical Reports Server (NTRS)

    Reshetov, V. D.

    1979-01-01

    The effect of solar flares on the weather on Earth is examined. It is concluded that the processes which arise in the atmosphere are so intricate that a single calculation of solar activity is insufficient for long-range forecasting. However, combined consideration of processes dependent upon the dynamic instability of the atmosphere and the effect of solar activity will contribute to the improvement of long-range forecasts.

  18. Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

    NASA Astrophysics Data System (ADS)

    Nowack, Peer Johannes; Abraham, Nathan Luke; Braesicke, Peter; Pyle, John Adrian

    2016-03-01

    Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

  19. Water loss from Venus: Implications for the Earth's early atmosphere

    NASA Technical Reports Server (NTRS)

    Richardson, S. M.; Pollack, J. B.; Reynolds, R. T.

    1985-01-01

    The atmosphere of Venus outgassed rapidly as a result of planetary heating during accretion, resulting in massive water loss. The processes affecting atmospheric chemistry following accretion have consisted largely of hydrogen escape and internal re-equilibrium. The initial bulk composition of Venus and Earth are assumed to have been roughly similar. Chemical speciation on Venus was controlled by the temperature and oxygen buffering capacity of the surface magma. It is also assumed that the surfaces of planetary bodies of the inner solar system were partly or wholly molten during accretion with a temperature estimated at 1273 to 1573 K. To investigate the range of reasonable initial atmospheric compositions on Venus, limits have to be set for the proportion of total hydrogen and the buffered fugacity of oxygen. Using the C/H ratio of 0.033 set for Earth, virtually all of the water generated during outgassing must later have been lost in order to bring the current CO2/H2O ratio for Venus up to its observed value of 10 sup 4 to 10 sup 5. The proportion of H2O decreases in model atmospheres with successfully higher C/H values, ultimately approaching the depleted values currently observed on Venus. Increasing C/H also results in a rapid increase in CO/H2O and provides an efficient mechanism for water loss by the reaction CO+H2O = CO2 + H2. This reaction, plus water loss mechanisms involving crustal iron, could have removed a very large volume of water from the Venusian atmosphere, even at a low C/H value.

  20. Water loss from Venus: Implications for the Earth's early atmosphere

    NASA Technical Reports Server (NTRS)

    Richardson, S. M.; Pollack, J. B.; Reynolds, R. T.

    1985-01-01

    The atmosphere of Venus outgassed rapidly as a result of planetary heating during accretion, resulting in massive water loss. The processes affecting atmospheric chemistry following accretion have consisted largely of hydrogen escape and internal re-equilibrium. The initial bulk composition of Venus and Earth are assumed to have been roughly similar. Chemical speciation on Venus was controlled by the temperature and oxygen buffering capacity of the surface magma. It is also assumed that the surfaces of planetary bodies of the inner solar system were partly or wholly molten during accretion with a temperature estimated at 1273 to 1573 K. To investigate the range of reasonable initial atmospheric compositions on Venus, limits have to be set for the proportion of total hydrogen and the buffered fugacity of oxygen. Using the C/H ratio of 0.033 set for Earth, virtually all of the water generated during outgassing must later have been lost in order to bring the current CO2/H2O ratio for Venus up to its observed value of 10 sup 4 to 10 sup 5. The proportion of H2O decreases in model atmospheres with successfully higher C/H values, ultimately approaching the depleted values currently observed on Venus. Increasing C/H also results in a rapid increase in CO/H2O and provides an efficient mechanism for water loss by the reaction CO+H2O = CO2 + H2. This reaction, plus water loss mechanisms involving crustal iron, could have removed a very large volume of water from the Venusian atmosphere, even at a low C/H value.

  1. Observations and Modeling of Solar Flare Atmospheric Dynamics

    NASA Astrophysics Data System (ADS)

    Li, Y.

    2015-09-01

    Solar flares are one of the most energetic events in solar atmosphere, which last minutes to tens of minutes. The eruption of a solar flare involves energy release, plasma heating, particle acceleration, mass flows, waves, etc. A solar flare releases a large amount of energy, and its emission spans a wide wavelength range. Solar flares are usually accompanied by coronal mass ejections (CMEs); therefore they could significantly affect the space environments between the Earth and the Sun. At present, we do not fully understand the whole flare process. There are still many important questions to be resolved, such as when and where is the energy released? How long does the energy release last? What are the main ways of energy release? And how does the solar atmosphere respond to the energy release? To address these questions, we study in detail the flare heating and dynamic evolution. We first give a brief review of previous flare studies (Chapter 1), and introduce the observing instruments (Chapter 2) and the modeling method (Chapter 3) related to this thesis work. Then we use spectral data to investigate the chromospheric evaporation (Chapter 4). Based on the results, we further explore the flare heating problem. With observationally inferred heating functions, we model two flare loops, and compare the results with observations (Chapter 5). A consistency is achieved between modeling and observations. In addition, we model two different sets of flare loop systems with quite different heating profiles and dynamic evolutions (Chapter 6). The details are described as below. Firstly, we investigate the chromospheric evaporation in the flare on 2007 January 16 using line profiles observed by the Extreme-ultraviolet (EUV) Imaging Spectrometer (EIS) on board Hinode. Three points with different magnetic polarities at flare ribbons are analyzed in detail. We find that the three points show different patterns of upflows and downflows in the impulsive phase of the flare. The

  2. Solar Implications of ULYSSES Interplanetary Field Measurements

    NASA Astrophysics Data System (ADS)

    Wang, Y.-M.; Sheeley, N. R., Jr.

    1995-07-01

    Recent observations by the Ulysses magnetometer team have shown that the strength of the radial interplanetary field component, |Br| , is essentially independent of latitude, a result which implies that the heliospheric currents are confined entirely to thin sheets. Using such a current sheet model, we extrapolate the observed photospheric field to 1 AU and compare the predicted magnitude and sign of Br with spacecraft measurements during 1970--1993. Approximate agreement can be obtained if the solar magnetograph measurements in the Fe I lambda 5250 line are scaled upward by a latitude-dependent factor, similar to that derived by Ulrich from a study of magnetic saturation effects. The correction factor implies sharply peaked polar fields near sunspot minimum, with each polar coronal hole having a mean field strength of 10 G.

  3. A comprehensive NMR structural study of Titan aerosol analogs: Implications for Titan's atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    He, Chao; Smith, Mark A.

    2014-11-01

    Titan has a thick atmosphere composed primarily of nitrogen and methane. Complex organic chemistry induced by solar ultraviolet radiation and energetic particles, takes place in Titan's upper atmosphere, producing an optically thick reddish brown carbon based haze encircling this moon. The chemistry in Titan's atmosphere and its resulting chemical structures are still not fully understood in spite of a great many efforts being made. In our previous work, we have investigated the structure of the 13C and 15N labeled, simulated Titan haze aerosols (tholin) by NMR and identified several dominant small molecules in the tholin. Here we report our expanded structural investigation of the bulk of the tholin by more comprehensive NMR study. The NMR results show that the tholin materials are dominated by heavily nitrogenated compounds, in which the macromolecular structures are highly branched polymeric or oligomeric compounds terminated in methyl, amine, and nitrile groups. The structural characteristic suggest that the tholin materials are formed via different copolymerization or incorporation mechanisms of small precursors, such as HCN, CH2dbnd NH, NH3 and C2H2. This study helps to understand the formation process of nitrogenated organic aerosols in Titan's atmosphere and their prebiotic implications.

  4. Investigation of Solar Cyclic and Climatic Trends in Upper Atmospheric Hydrogen Distributions

    NASA Astrophysics Data System (ADS)

    Nossal, Susan; Mierkiewicz, Edwin; Roesler, Fred; Qian, L.; Solomon, S.; Burns, Alan

    2013-03-01

    We will discuss work in progress to better understand solar cyclic and climatic influences on hydrogenous species budgets and distributions from both an observational and modeling perspective. Our Fabry-Perot observations of upper atmospheric hydrogen emissions during solar cycle 23 and during three solar minima (1985, 1997, 2006-2008) establish a reference data set of highly precise, consistently calibrated, thermospheric + exospheric hydrogen column emission observations from Northern mid-latitudes that can be used to compare with future observations and with atmospheric models. We will also discuss use of the National Center for Atmospheric Research's global mean model for sensitivity studies to investigate the response of thermospheric hydrogen to a doubling of carbon dioxide and methane. The results from this study suggest a strong solar cycle dependence and that carbon dioxide cooling may have a greater impact upon the changes in the upper atmospheric hydrogen distribution at solar minimum than do methane increases.

  5. IMPLICATIONS OF THE RECENT LOW SOLAR MINIMUM FOR THE SOLAR WIND DURING THE MAUNDER MINIMUM

    SciTech Connect

    Lockwood, M.; Owens, M. J.

    2014-01-20

    The behavior of the Sun and near-Earth space during grand solar minima is not understood; however, the recent long and low minimum of the decadal-scale solar cycle gives some important clues, with implications for understanding the solar dynamo and predicting space weather conditions. The speed of the near-Earth solar wind and the strength of the interplanetary magnetic field (IMF) embedded within it can be reliably reconstructed for before the advent of spacecraft monitoring using observations of geomagnetic activity that extend back to the mid-19th century. We show that during the solar cycle minima around 1879 and 1901 the average solar wind speed was exceptionally low, implying the Earth remained within the streamer belt of slow solar wind flow for extended periods. This is consistent with a broader streamer belt, which was also a feature of the recent low minimum (2009), and yields a prediction that the low near-Earth IMF during the Maunder minimum (1640-1700), as derived from models and deduced from cosmogenic isotopes, was accompanied by a persistent and relatively constant solar wind of speed roughly half the average for the modern era.

  6. Noble gases in planetary atmospheres - Implications for the origin and evolution of atmospheres

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.; Black, D. C.

    1982-01-01

    The radiogenic and primordial noble gas contents of the Venus, earth, and Mars atmospheres are compared with one another and with the noble gas content of other extraterrestrial samples, particularly meteorites. Key trends in the primordial noble gas content of terrestrial planetary atmospheres are shown to include: (1) a several-orders-of-magnitude decrease in Ne-20 and Ar-36 from Venus to earth to Mars; (2) a nearly constant Ne-20/Ar-36 ratio, which is comparable to that found in the more primitive carbonaceous chondrites and which is two orders of magnitude smaller than the solar ratio; (3) a sizable fractionation of Ar, Kr, and Xe from their solar ratios, though the degree of fractionation (especially for Ar-36/Xe-132) appears to decrease systematically from carbonaceous chondrites to Mars to earth to Venus; and (4) large differences in Ne and Xe isotopic ratios among earth, meteorites, and the sun. It is suggested that the grain-accretion hypothesis can explain all four trends, though the assumptions needed to achieve this agreement are far from proven.

  7. Ar Atmosphere: Implications for Structure and Composition of Mercury's Crust

    NASA Technical Reports Server (NTRS)

    Killen, R. M.; Morgan, T. H.

    2001-01-01

    We examine the possibilities of sustaining an argon atmosphere by diffusion from the upper 10 km of crust, and alternatively by effusion from a molten or previously molten area at great depth . Ar-40 in the atmospheres of the planets is a measure of potassium abundance in the interiors since Ar-40 is a product of radiogenic decay of K-40 by electron capture with the subsequent emission of a 1.46 eV gamma-ray. Although the Ar-40 in the earth's atmosphere is expected to have accumulated since the late bombardment, Ar-40 in surface-bounded exospheres is eroded quickly by photoionization and electron impact ionization. Thus, the argon content in the exospheres of the Moon, Mercury and probably Europa is representative of current effusion rather than accumulation over the lifetime of the body. Argon content will be a function of K content, temperature, grain size distribution, connected pore volume and possible seismic activity. Although Mercury and the Moon differ in many details, we can train the solutions to diffusion equations to predict the average lunar atmosphere. Then these parameters can be varied for Hermean conditions. Assuming a lunar crustal potassium abundance of 300 ppm, the observed argon atmosphere requires equilibrium between the argon production in the upper 9 Km of the moon (1.135 x 10(exp -3) cm(exp -3) s(exp -1)) and its loss. Hodges et al. conclude that this loss rate and the observed time variability requires argon release through seismic activity, tapping a deep argon source. An important observation is that the extreme surface of the Moon is enhanced in argon rather than depleted, as one would expect from outgassing of radiogenic argon. Manka and Michel concluded that ion implantation explains the surface enhancement of Ar-40. About half of the argon ions produced in the lunar atmosphere would return to the surface, where they would become embedded in the rocks. Similarly, at Mercury we expect the surface rocks to be enhanced in Ar-40 wherever

  8. A Solar Radiation Parameterization for Atmospheric Studies. Volume 15

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah; Suarez, Max J. (Editor)

    1999-01-01

    The solar radiation parameterization (CLIRAD-SW) developed at the Goddard Climate and Radiation Branch for application to atmospheric models are described. It includes the absorption by water vapor, O3, O2, CO2, clouds, and aerosols and the scattering by clouds, aerosols, and gases. Depending upon the nature of absorption, different approaches are applied to different absorbers. In the ultraviolet and visible regions, the spectrum is divided into 8 bands, and single O3 absorption coefficient and Rayleigh scattering coefficient are used for each band. In the infrared, the spectrum is divided into 3 bands, and the k-distribution method is applied for water vapor absorption. The flux reduction due to O2 is derived from a simple function, while the flux reduction due to CO2 is derived from precomputed tables. Cloud single-scattering properties are parameterized, separately for liquid drops and ice, as functions of water amount and effective particle size. A maximum-random approximation is adopted for the overlapping of clouds at different heights. Fluxes are computed using the Delta-Eddington approximation.

  9. ENERGY CONTENT AND PROPAGATION IN TRANSVERSE SOLAR ATMOSPHERIC WAVES

    SciTech Connect

    Goossens, M.; Van Doorsselaere, T.; Soler, R.; Verth, G.

    2013-05-10

    Recently, a significant amount of transverse wave energy has been estimated propagating along solar atmospheric magnetic fields. However, these estimates have been made with the classic bulk Alfven wave model which assumes a homogeneous plasma. In this paper, the kinetic, magnetic, and total energy densities and the flux of energy are computed for transverse MHD waves in one-dimensional cylindrical flux tube models with a piecewise constant or continuous radial density profile. There are fundamental deviations from the properties for classic bulk Alfven waves. (1) There is no local equipartition between kinetic and magnetic energy. (2) The flux of energy and the velocity of energy transfer have, in addition to a component parallel to the magnetic field, components in the planes normal to the magnetic field. (3) The energy densities and the flux of energy vary spatially, contrary to the case of classic bulk Alfven waves. This last property has the important consequence that the energy flux computed with the well known expression for bulk Alfven waves could overestimate the real flux by a factor in the range 10-50, depending on the flux tube equilibrium properties.

  10. Jet Formation in Solar Atmosphere due to Magnetic Reconnection

    NASA Astrophysics Data System (ADS)

    González-Avilés, J. J.; Guzmán, F. S.; Fedun, V.

    2017-02-01

    Using numerical simulations, we show that jets with features of type II spicules and cool coronal jets corresponding to temperatures of 104 K can be formed as a result of magnetic reconnection in a scenario with magnetic resistivity. For this, we model the low chromosphere–corona region using the C7 equilibrium solar atmosphere model, assuming that resistive MHD rules the dynamics of the plasma. The magnetic field configurations we analyze correspond to two neighboring loops with opposite polarity. The formation of a high-speed and sharp structure depends on the separation of the loops’ feet. We analyze the cases where the magnetic field strength of the two loops is equal and different. In the first case, with a symmetric configuration the jets rise vertically, whereas in an asymmetric configuration the structure shows an inclination. With a number of simulations carried out under a 2.5D approach, we explore various properties of the excited jets, namely, inclination, lifetime, and velocity. The parameter space involves a magnetic field strength between 20 and 40 G, and the resistivity is assumed to be uniform with a constant value of the order {10}-2{{Ω }}\\cdot m.

  11. Solar spectral irradiance and atmospheric transmission at Mauna Loa Observatory

    SciTech Connect

    Shaw, G.E.

    1982-06-01

    A radiometer was operated at the Mauna Loa Observatory during calendar year 1980 to estimate the spectral irradiance of the sun and its possible fluctuation in time near the peak of solar activity. Data were also acquired on seasonal trends of atmospheric transmissivity above the marine mixing layer in the central Pacific. Spectral irradiance remained c constant to at least 1/2% at all wavelengths monitored. Furthermore its absolute magnitude was in agreement with the Labs and Neckel values to +- 2% except at blue wavelengths where the Mauna Loa values are from 4 to 12% higher and at lambda = 850 nm where the Mauna Loa value is 9% lower. The residual aerosol optical depth above Mauna Loa Observatory during 1980 averaged tau/sub 0/ = 0.020. An intrusion of dust into the central Pacific from the Gobi Desert (as deduced by the composition of collected particles) invaded the Central Pacific from Mar. to May 19890 and caused a perturbation in optical depth (at lambda = 500 nm) of ..delta..tau/sub 0/approx.0.01--0.02. The optical depth increment caused by the Mt. St. Helens volcano was <0.005 in the 2-month period following the eruption.

  12. Solar spectral irradiance and atmospheric transmission at Mauna Loa Observatory.

    PubMed

    Shaw, G E

    1982-06-01

    A radiometer was operated at the Mauna Loa Observatory during calendar year 1980 to estimate the spectral irradiance of the sun and its possible fluctuation in time near the peak of solar activity. Data were also acquired on seasonal trends of atmospheric transmissivity above the marine mixing layer in the central Pacific. Spectral irradiance remained constant to at least (1/2)% at all wavelengths monitored. Furthermore its absolute magnitude was in agreement with the Labs and Neckel values to +/-2% except at blue wavelengths where the Mauna Loa values are from 4 to 12% higher and at lambda = 850 nm where the Mauna Loa value is 9% lower. The residual aerosol optical depth above Mauna Loa Observatory during 1980 averaged tau(0) = 0.020. An intrusion of dust into the central Pacific from the Gobi Desert (as deduced by the composition of collected particles) invaded the Central Pacific from Mar. to May 1980 and caused a perturbation in optical depth (at lambda = 500 nm) of Deltatau(0) ~ 0.01-0.02. The optical depth increment caused by the Mt. St. Helens volcano was <0.005 in the 2-month period following the eruption.

  13. On the atmospheric water vapor transmission function for solar radiation models

    SciTech Connect

    Psiloglou, B.E. ); Santamouris, M. ); Asimakopoulos, D.N. Univ. of Athens )

    1994-11-01

    A new expression for the integral transmission of atmospheric water vapor has been developed. This expression is based on the latest known water vapor spectral absorption data, on a new vertical atmospheric profile and finally, on the Neckel and Labs model, incorporating the most recent corrections of the extraterrestrial solar spectrum. The proposed expression can be easily used by solar radiation models in order to predict the beam, diffuse, and global solar radiation, especially in regions where the vertical atmospheric profile is similar to that in Athens.

  14. Energy deposition in the earth's atmosphere due to impact of solar activity-generated disturbances

    NASA Technical Reports Server (NTRS)

    Wu, S. T.; Kan, L. C.; Tandberg-Hanssen, E.; Dryer, M.

    1979-01-01

    Energy deposition in and dynamic responses of the terrestrial atmosphere to solar flare-generated shocks and other physical processes - such as particle precipitation and local heating - are investigated self-consistently in the context of hydrodynamics, the problem being treated as an initial boundary-value problem. It is extremely difficult to construct a general model for the line solar activity-magnetosphere-atmosphere; however, a limited model for this link is possible. The paper describes such a model, and presents some results on energy deposition into the earth's atmosphere due to solar activity-generated disturbances. Results from the present calculations are presented and discussed.

  15. Expanding Box simulations: implications the Solar Probe Plus and Solar Orbiter missions.

    NASA Astrophysics Data System (ADS)

    Verdini, A.

    2014-12-01

    Recent three-dimensional simulations in the Expanding Box Model (EBM) show how the radial evolution of the spectral anisotropy of turbulence depends on the unknown coronal spectrum. However, regardless of the source spectrum, the solar wind expansion causes 1) the emergence of microstream structures and 2) a well defined component anisotropy.I will discuss the implications of such findings for the expected turbulent spectrum in the inner heliosphere and for the identification of microstreams in Solar Probe Plus records. I will also show how the EBM can be used to cross-check the 1D spectrum and to get insights on the unknown 3D structure of turbulence during radial alignment configurations of Solar Orbiter and Solar Probe Plus.

  16. Implications of L1 observations for slow solar wind formation by solar reconnection

    NASA Astrophysics Data System (ADS)

    Kepko, L.; Viall, N. M.; Antiochos, S. K.; Lepri, S. T.; Kasper, J. C.; Weberg, M.

    2016-05-01

    While the source of the fast solar wind is known to be coronal holes, the source of the slow solar wind has remained a mystery. Long time scale trends in the composition and charge states show strong correlations between solar wind velocity and plasma parameters, yet these correlations have proved ineffective in determining the slow wind source. We take advantage of new high time resolution (12 min) measurements of solar wind composition and charge state abundances at L1 and previously identified 90 min quasiperiodic structures to probe the fundamental timescales of slow wind variability. The combination of new high temporal resolution composition measurements and the clearly identified boundaries of the periodic structures allows us to utilize these distinct solar wind parcels as tracers of slow wind origin and acceleration. We find that each 90 min (2000 Mm) parcel of slow wind has near-constant speed yet exhibits repeatable, systematic charge state and composition variations that span the entire range of statistically determined slow solar wind values. The classic composition-velocity correlations do not hold on short, approximately hourlong, time scales. Furthermore, the data demonstrate that these structures were created by magnetic reconnection. Our results impose severe new constraints on slow solar wind origin and provide new, compelling evidence that the slow wind results from the sporadic release of closed field plasma via magnetic reconnection at the boundary between open and closed flux in the Sun's atmosphere.

  17. Implications of L1 Observations for Slow Solar Wind Formation by Solar Reconnection

    NASA Technical Reports Server (NTRS)

    Kepko, L.; Viall, N. M.; Antiochos, S. K.; Lepri, S. T.; Kasper, J. C.; Weberg, M.

    2016-01-01

    While the source of the fast solar wind is known to be coronal holes, the source of the slow solar wind has remained a mystery. Long time scale trends in the composition and charge states show strong correlations between solar wind velocity and plasma parameters, yet these correlations have proved ineffective in determining the slow wind source. We take advantage of new high time resolution (12 min) measurements of solar wind composition and charge state abundances at L1 and previously identified 90 min quasi periodic structures to probe the fundamental timescales of slow wind variability. The combination of new high temporal resolution composition measurements and the clearly identified boundaries of the periodic structures allows us to utilize these distinct solar wind parcels as tracers of slowwind origin and acceleration. We find that each 90 min (2000 Mm) parcel of slow wind has near-constant speed yet exhibits repeatable, systematic charge state and composition variations that span the entire range of statistically determined slow solar wind values. The classic composition-velocity correlations do not hold on short, approximately hour long, time scales. Furthermore, the data demonstrate that these structures were created by magnetic reconnection. Our results impose severe new constraints on slow solar wind origin and provide new, compelling evidence that the slow wind results from the sporadic release of closed field plasma via magnetic reconnection at the boundary between open and closed flux in the Sun's atmosphere.

  18. Advances in solar flare science through modeling of the magnetic field in the solar atmosphere (Arne Richter Award for Outstanding ECSs Lecture)

    NASA Astrophysics Data System (ADS)

    Thalmann, Julia K.

    2017-04-01

    Ever since we know of the phenomenon of solar flares and coronal mass ejections, we try to unravel the secrets of the underlying physical processes. The magnetic field in the Sun's atmosphere is the driver of any solar activity. Therefore, the combined study of the surface (photosphere) magnetic field and the magnetic field in the atmosphere above (the chromosphere and corona) is essential. At present, direct measurements of the solar magnetic field are regularly available only for the solar surface, so that we have to rely on models to reconstruct the magnetic field in the corona. Corresponding model-based research on the magnetic field within flaring active regions is inevitable for the understanding of the key physical processes of flares and possibly associated mass ejections, as well as their time evolution. I will focus on recent advances in the understanding of the magnetic processes in solar flares based on quasi-static force-free coronal magnetic field modeling. In particular, I will discuss aspects such as the structure (topology) of the coronal magnetic field, its flare-induced reconfiguration, as well as the associated modifications to the inherent magnetic energy and helicity. I will also discuss the potential and limitations of studies trying to cover the complete chain of action, i.e., to relate the (magnetic) properties of solar flares to that of the associated disturbances measured in-situ at Earth, as induced by flare-associated coronal mass ejections after passage of the interplanetary space separating Sun and Earth. Finally, I will discuss future prospects regarding model-based research of the coronal magnetic field in the course of flares, including possible implications for improved future flare forecasting attempts.

  19. Measurement of atmospheric precipitable water using a solar radiometer. [water vapor absorption effects

    NASA Technical Reports Server (NTRS)

    Pitts, D. E.; Dillinger, A. E.; Mcallum, W. E.

    1974-01-01

    A technique is described and tested that allows the determination of atmospheric precipitable water from two measurements of solar intensity: one in a water-vapor absorption band and another in a nearby spectral region unaffected by water vapor.

  20. Solar Atmospheric Energy Redistribution Across Multiple Classes of Observable Sources of Solar Radiation

    NASA Astrophysics Data System (ADS)

    Orange, Norton Brice

    This thesis investigates solar atmospheric energy redistribution across multiple classes of observable sources, while carrying out extensive work for increasing the proficiency of solar observational data's scientific return via a semi-autonomous data-acquisition algorithm. Minimal long-term pointing variations between limb and correlation derived pointings of the Atmospheric Imaging Assembly (AIA) and Helioseismic Magnetic Imager instruments provide evidence that the image-center positions achieve single-pixel accuracy on time scales shorter than their characterization. However, daily AIA passband pointing variations indicate autonomous sub-arcsecond co-registration is not yet fully achievable. Three year variations of ultra-violet (UV), far UV, and extreme-UV flux in coronal hole (CH), quiet Sun (QS), active region (AR), and flares (FLs), as well as irradiances, are consistent with expected trends of chromospheric, transition region (TR), and coronal plasmas. Radiative and magnetic energy couplings reveal a self-similarity between CH, QS, and ARs; indicative of a single dominant heating mechanism. FLs provide evidence of a runaway self-organized criticality of flaring activity -- a heating component married to the magnetic field distribution. Large scale statistical properties of BP phenomena, and a detailed comparison of a transition region BP, coronal BP, and blinker, indicated that measuring similar characteristics across multiple event types holds class-predictive power, and is a significant step towards automated multi-class classification of unresolved transient EUV sources. This work directly ties the catastrophic cooling of a cool loop to its non-equilibrium structure (via reconnection at a single footpoint site), and indicates the TR as its heating site due to subsequent plasma evaporation. The first evidence of "S-shape" loop arcades at TR temperatures in QS conditions is provided, as well as that their demise, i.e., relaxed non-potential magnetic

  1. Non-LTE H2+ as the source of missing opacity in the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Swamy, K. S. K.; Stecher, T. P.

    1974-01-01

    The population of the various vibrational levels of the H2+ molecule has been calculated from the consideration of formation and destruction mechanisms. The resulting population is used in calculating the total absorption due to H2+ and is compared with the other known sources of opacity at several optical depths of the solar atmosphere. It is shown that the absorption due to H2+ can probably account for the missing ultraviolet opacity in the solar atmosphere.

  2. On the physics of waves in the solar atmosphere: Wave heating and wind acceleration

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.

    1994-01-01

    This paper presents work performed on the generation and physics of acoustic waves in the solar atmosphere. The investigators have incorporated spatial and temporal turbulent energy spectra in a newly corrected version of the Lighthill-Stein theory of acoustic wave generation in order to calculate the acoustic wave energy fluxes generated in the solar convective zone. The investigators have also revised and improved the treatment of the generation of magnetic flux tube waves, which can carry energy along the tubes far away from the region of their origin, and have calculated the tube wave energy fluxes for the sun. They also examine the transfer of the wave energy originated in the solar convective zone to the outer atmospheric layers through computation of wave propagation and dissipation in highly nonhomogeneous solar atmosphere. These waves may efficiently heat the solar atmosphere and the heating will be especially significant in the chromospheric network. It is also shown that the role played by Alfven waves in solar wind acceleration and coronal hole heating is dominant. The second part of the project concerned investigation of wave propagation in highly inhomogeneous stellar atmospheres using an approach based on an analytic tool developed by Musielak, Fontenla, and Moore. In addition, a new technique based on Dirac equations has been developed to investigate coupling between different MHD waves propagating in stratified stellar atmospheres.

  3. On the physics of waves in the solar atmosphere: Wave heating and wind acceleration

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.

    1993-01-01

    This paper presents work performed on the generation and physics of acoustic waves in the solar atmosphere. The investigators have incorporated spatial and temporal turbulent energy spectra in a newly corrected version of the Lighthill-Stein theory of acoustic wave generation in order to calculate the acoustic wave energy fluxes generated in the solar convective zone. The investigators have also revised and improved the treatment of the generation of magnetic flux tube waves, which can carry energy along the tubes far away from the region of their origin, and have calculated the tube energy fluxes for the sun. They also examine the transfer of the wave energy originated in the solar convective zone to the outer atmospheric layers through computation of wave propagation and dissipation in highly nonhomogeneous solar atmosphere. These waves may efficiently heat the solar atmosphere and the heating will be especially significant in the chromospheric network. It is also shown that the role played by Alfven waves in solar wind acceleration and coronal hole heating is dominant. The second part of the project concerned investigation of wave propagation in highly inhomogeneous stellar atmospheres using an approach based on an analytic tool developed by Musielak, Fontenla, and Moore. In addition, a new technique based on Dirac equations has been developed to investigate coupling between different MHD waves propagating in stratified stellar atmospheres.

  4. The effect of solar forcing induced atmospheric perturbations on LEO satellites' nominal aerodynamic drag

    NASA Astrophysics Data System (ADS)

    Nwankwo, Victor U. J.; Chakrabarti, Sandip Kumar; Weigel, Robert

    2016-07-01

    Atmospheric drag is the strongest force perturbing the motion of satellites in low Earth orbits LEO, and could cause re-entry of satellites, difficulty in identifying and tracking of the satellites and other space objects, manuvering and prediction of lifetime and re-entry. Solar activities influence the temperature, density and composition of the upper atmosphere. These effects thus strongly depend on the phase of a solar cycle. The frequency of intense flares and storms increase during solar maximum. Heating up of the atmosphere causes its expansion eventually leading to accelerated drag of orbiting satellites, especially those in LEO. In this paper, we present the model of the atmospheric drag effect on the trajectory of hypothetical LEO satellites of different ballistic coefficients. We investigate long-term trend of atmospheric drag on LEO satellites due to solar forcing induced atmospheric perturbations and heating at different phases of the solar cycle, and during interval of strong geomagnetic disturbances or storms. We show the dependence of orbital decay on severity of both the solar cycle and phase, and the extent of geomagnetic perturbations. The result of the model compares well with the observed decay profile of existing LEO satellites and provides a better understanding of the issue of the orbital decay. Our result may also be useful for selection of launch window of satellites for an extended lifetime in the orbit.

  5. [Common periodicity of solar atmosphere rotation and function of the human body].

    PubMed

    Tiagun, N F

    1995-01-01

    The study is made of the occurrence rates of menstrual cycle periods for approximately 2000 women. Peaks on the distribution histogram, corresponding to 21, 25, 28 and 30 days, coincide with a set of axial rotation periods of the solar atmosphere. It is proposed that the functioning of human organism is determined not only by the Moon but by the rhythmics of solar system.

  6. The Solar Atmosphere at Three Temperatures During a Coronal Mass Ejection

    NASA Technical Reports Server (NTRS)

    Zhitnik, I.; Pertzov, A.; Oparin, S.; Oraevsky, V.; Slemzin, V.; Sobelman, I.; Feynman, J.; Goldstein, B.

    1998-01-01

    On April 14, 1994 a major coronal mass ejection (CME) occured while the solar atmosphere was being observed in XUV by the Terek C instrument aboard the CORONAS spacecraft. We here compare the TEREK data before and after the CME with the Yohkoh soft x-ray data and the National Solar Observatory He I 10830 data from April 13 and 14.

  7. The Solar Atmosphere at Three Temperatures During a Coronal Mass Ejection

    NASA Technical Reports Server (NTRS)

    Zhitnik, I.; Pertzov, A.; Oparin, S.; Oraevsky, V.; Slemzin, V.; Sobelman, I.; Feynman, J.; Goldstein, B.

    1998-01-01

    On April 14, 1994 a major coronal mass ejection (CME) occured while the solar atmosphere was being observed in XUV by the Terek C instrument aboard the CORONAS spacecraft. We here compare the TEREK data before and after the CME with the Yohkoh soft x-ray data and the National Solar Observatory He I 10830 data from April 13 and 14.

  8. Martian upper atmosphere response to solar EUV flux and soft X-ray flares

    NASA Astrophysics Data System (ADS)

    Jain, Sonal; Stewart, Ian; Schneider, Nicholas M.; Deighan, Justin; Stiepen, Arnaud; Evans, J. Scott; Stevens, Michael H.; Chaffin, Michael S.; Crismani, Matteo; McClintock, William; Montmessin, Franck; Thiemann, E. M.; Eparvier, Frank; Chamberlin, Phillip C.; Jacosky, Bruce

    2016-10-01

    Planetary upper atmosphere energetics is mainly governed by absorption of solar extreme ultraviolet (EUV) radiation. Understanding the response of planetary upper atmosphere to the daily, long and short term variation in solar flux is very important to quantify energy budget of upper atmosphere. We report a comprehensive study of Mars dayglow observations made by the IUVS instrument aboard the MAVEN spacecraft, focusing on upper atmospheric response to solar EUV flux. Our analysis shows both short and long term effect of solar EUV flux on Martian thermospheric temperature. We find a significant drop (> 100 K) in thermospheric temperature between Ls = 218° and Ls = 140°, attributed primarily to the decrease in solar activity and increase in heliocentric distance. IUVS has observed response of Martian thermosphere to the 27-day solar flux variation due to solar rotation.We also report effect of two solar flare events (19 Oct. 2014 and 24 March 2015) on Martian dayglow observations. IUVS observed about ~25% increase in observed brightness of major ultraviolet dayglow emissions below 120 km, where most of the high energy photons (< 10 nm) deposit their energy. The results presented in this talk will help us better understand the role of EUV flux in total heat budget of Martian thermosphere.

  9. Implications of the Nitrogen Isotope Ratio in Titan's Atmosphere for the Nitrogen Ratio in Ammonia in Comets

    NASA Astrophysics Data System (ADS)

    Mandt, K.; Mousis, O.

    2013-12-01

    The D/H ratio of water measured in solar system bodies has been established as a tool for determining the conditions under which bodies such as comets or icy moons formed. This ratio varies significantly and indicates complex thermal and chemical evolution of the solar nebula during solar system and planetary formation. Nitrogen isotope ratios also vary significantly, and in some but not all cases correlate to D/H ratios, but are poorly understood. Nitrogen in the solar nebula was primarily in the form of atomic and molecular nitrogen. The isotope ratio (14N/15N) of this reservoir is expected to be ~435 based on the ratio measured in Jupiter's atmosphere, because the atmosphere of Jupiter is made up of gas captured from the solar nebula (Owen et al., 2001). The terrestrial atmospheric ratio is 272, which is close to the ratio measured in the Earth's mantle. This may be the primordial ratio for nitrogen delivered to Earth depending on the amount of exchange between the atmosphere and the mantle and any atmospheric fractionation processes that may have influenced the ratio over time. Comets are a possible source of nitrogen in the Earth's atmosphere (Hutsmekers et al., 2009), although chondrites have also been suggested as a source (Marty, 2012). In the case of comets, nitrogen would have been essentially retained in the form of ammonia (Mousis et al., 2012), which is the most abundant form of nitrogen in comets. The nitrogen in Titan's atmosphere is expected to have originated as ammonia hydrates and converted to N2 early in Titan's history (Atreya et al., 1978). The nitrogen ratio in Titan's atmosphere is ~170, which is significantly enriched in the heavy isotope compared to the terrestrial value. We will discuss the evolution of the nitrogen ratio in Titan's atmosphere (Mandt et al., 2009), the limits of the primordial ratio in ammonia, and the implications for this ratio for the isotope ratio in ammonia in comets that should be measured by the ROSINA instrument

  10. Recent Observational Results on Electron Acceleration in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Reid, Hamish

    2013-04-01

    The Sun is the largest and most energetic particle accelerator in our solar system. During solar flares, magnetic explosions commonly accelerate electrons to energies in the deca-keV range and above. In the larger flares it is also possible to observe relativistic electrons. We can detect high energy electrons directly via in-situ observations near the Earth and indirectly via the electromagnetic emission they create in a wide spectrum of wavelengths. After a brief overview I will present some of the recent observational results from solar flare electron acceleration and the new insight they are granting us. I will also mention the energy, space, and time scales that are important for solar flares and how this relates to other electron acceleration processes in the solar system (e.g. in the solar wind and the Earth's magnetosphere).

  11. Origins of the Ambient Solar Wind: Implications for Space Weather

    NASA Astrophysics Data System (ADS)

    Cranmer, Steven R.; Gibson, Sarah E.; Riley, Pete

    2017-10-01

    The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress—in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory—that gives us hope that the above problems are indeed solvable.

  12. Implications of the Deep Minimum for Slow Solar Wind Origin

    NASA Astrophysics Data System (ADS)

    Antiochos, S. K.; Mikic, Z.; Lionello, R.; Titov, V. S.; Linker, J. A.

    2009-12-01

    The origin of the slow solar wind has long been one of the most important problems in solar/heliospheric physics. Two observational constraints make this problem especially challenging. First, the slow wind has the composition of the closed-field corona, unlike the fast wind that originates on open field lines. Second, the slow wind has substantial angular extent, of order 30 degrees, which is much larger than the widths observed for streamer stalks or the widths expected theoretically for a dynamic heliospheric current sheet. We propose that the slow wind originates from an intricate network of narrow (possibly singular) open-field corridors that emanate from the polar coronal hole regions. Using topological arguments, we show that these corridors must be ubiquitous in the solar corona. The total solar eclipse in August 2008, near the lowest point of the Deep Minimum, affords an ideal opportunity to test this theory by using the ultra-high resolution Predictive Science's (PSI) eclipse model for the corona and wind. Analysis of the PSI eclipse model demonstrates that the extent and scales of the open-field corridors can account for both the angular width of the slow wind and its closed-field composition. We discuss the implications of our slow wind theory for the structure of the corona and heliosphere at the Deep Minimum and describe further observational and theoretical tests. This work has been supported by the NASA HTP, SR&T, and LWS programs.

  13. Impacts of Stratospheric Dynamics on Atmospheric Behavior from the Ground to Space Solar Minimum and Solar Maximum

    DTIC Science & Technology

    2015-12-15

    2) the influence of the stratosphere on the tropospheric climate during different phases of the solar cycle. In addition, a third objective of our...newly developed and updated extension of the Whole Atmosphere Community Climate Model (WACCM-X) to 500km which provides the most comprehensive...team members in the validation of the thermospheric products. Accomplishments A. WACCM-X Development: The NCAR Whole Atmosphere Community Climate

  14. Solar-wind tritium limit and the mixing rate of the solar atmosphere. [from recovered Surveyor 3 parts

    NASA Technical Reports Server (NTRS)

    Fireman, E. L.

    1976-01-01

    Tritium has been measured, in Surveyor 3 samples, some of which were adjacent to those in which solar-wind-implanted He-4 had previously been measured. Little of the H-3 can be attributed to solar-wind implantation. The upper limit for the H-3/He-4 ratio in the solar wind is four times ten to the minus tenth power and corresponds to a H-3/H-1 limit of two times ten to the minus eleventh power. This limit imposes a requirement on the mixing rate in the solar atmosphere if the H-3 production rate in solar-surface nuclear reactions is greater than 160 sq cm/sec.

  15. Influence of solar-probe inherent atmosphere on in-situ observations

    SciTech Connect

    Hassanein, A.; Konkashbaev, A.I.; Konkashbaev, I.K.; Nikandrov, L.B.

    1998-08-01

    The solar corona is the source of the solar wind, which is responsible for the heliosphere and plays a crucial role in solar/terrestrial phenomena. A comprehensive understanding of these phenomena can be established only by directly measuring ion and electron velocity distributions, plasma waves, and fluxes of energetic particles near the sun. The problem resulting from the inherent atmosphere of a spacecraft moving in the vicinity of the sun and the influence of this atmosphere on in-situ measurements of the solar corona plasma is key to the realization and success of any solar probe mission. To evaluate the influence of the probe-inherent atmosphere on in-situ observations, the authors have developed comprehensive radiation hydrodynamic models. The physics of plasma/probe/vapor interaction are also being developed in a self-consistent model to predict the effect of probe inherent atmosphere on in-situ measurements of corona parameters during solar flares. Interaction of the ionized atmosphere with the ambient natural plasma will create a turbulent shock wave that can affect in-situ measurements and must be taken into account in designing the spacecraft and its scientific components.

  16. Improving the Ni I atomic model for solar and stellar atmospheric models

    SciTech Connect

    Vieytes, M. C.; Fontenla, J. M. E-mail: johnf@digidyna.com

    2013-06-01

    Neutral nickel (Ni I) is abundant in the solar atmosphere and is one of the important elements that contribute to the emission and absorption of radiation in the spectral range between 1900 and 3900 Å. Previously, the Solar Radiation Physical Modeling (SRPM) models of the solar atmosphere only considered a few levels of this species. Here, we improve the Ni I atomic model by taking into account 61 levels and 490 spectral lines. We compute the populations of these levels in full NLTE using the SRPM code and compare the resulting emerging spectrum with observations. The present atomic model significantly improves the calculation of the solar spectral irradiance at near-UV wavelengths, which is important for Earth atmospheric studies, and particularly for ozone chemistry.

  17. Mars atmospheric losses induced by the solar wind: current knowledge and perspective

    NASA Astrophysics Data System (ADS)

    Ermakov, Vladimir; Zelenyi, Lev; Vaisberg, Oleg; Sementsov, Egor; Dubinin, Eduard

    2017-04-01

    Solar wind induced atmospheric losses have been studied since earlier 1970th. Several loss channels have been identified including pick-up of exospheric photo-ions and ionospheric ions escape. Measurements performed during several solar cycles showed variation of these losses by about factor of 10, being largest at maximum solar activity. MAVEN spacecraft equipped with comprehensive set of instruments with high temporal and mass resolution operating at Mars since fall 2014 ensures much better investigation of solar wind enforcing Martian environment, Mars atmospheric losses processes and mass loss rate. These issues are very important for understanding of Martian atmospheric evolution including water loss during cosmogonic time. Simultaneous observations by MAVEN and MEX spacecraft open the new perspective in study of Martian environment. In this report we discuss results of past and current missions and preliminary analysis of heavy ions escape using simultaneous measurements of MEX and MAVEN spacecraft.

  18. Method and apparatus for measuring solar activity and atmospheric radiation effects

    NASA Technical Reports Server (NTRS)

    Haroules, G. G.; Brown, W. E., III (Inventor)

    1973-01-01

    A radiometric measuring system is described for observing solar activity, atmospheric attenuation, and atmospheric emission. Two highly directional microwave antennas are mounted side by-side on an equatorial mount which tracks the sun. One antenna is aimed directly at the sun to provide a sun temperature, and the other antenna is aimed at a slight angle to the sun antenna to provide a sky temperature reference. Signals from the two antennas are compared in a radiometric detecting system and provide information concerning solar activity and atmospheric attenuation and emission.

  19. Ionization in Earth's atmosphere following the solar storm on January 20, 2005

    NASA Astrophysics Data System (ADS)

    Seripienlert, A.; Mitthumsiri, W.; Saiz, A.; Ruffolo, D. J.; Mangeard, P. S.; Tortermpun, U.

    2014-12-01

    To estimate possible effects of atmospheric ionization on clouds and Earth's climate as well as radiation exposure of air travelers and aircraft electronics due to space weather, relativistic solar ions are the only solar particles of concern because the less energetic particles do not penetrate to cloud/aircraft altitudes. Some solar storms produce relativistic ions that lead to showers of secondary particles in Earth's atmosphere and generate signals in ground-based detectors such as neutron monitors at a rate that can be observed above the background due to galactic cosmic rays, hence the term ground-level enhancements (GLEs). In this work we study the January 20, 2005 event, one of the most intense GLEs ever observed. From the bare counter to neutron monitor count rate ratio at South Pole, we estimate a spectral index in rigidity of 5.0. From the Spaceship Earth network, supplemented to comprise 13 polar neutron monitors, we model the time profile of relativistic solar ions impinging on Earth's atmosphere in the polar regions. We then perform Monte Carlo simulations using a realistic atmospheric model to determine ionization as a function of altitude and time in Earth's atmosphere. The results will allow us to investigate a possible connection between solar activity and Earth's climate as mediated by the cosmic ray flux, atmospheric ionization, and cloud formation. This work is partially supported by Thailand Research Fund and a Postdoctoral Fellowship from Mahidol University.

  20. Preliminary experiment requirements document for Solar and Terrestrial Atmospheres Spectrometer (STAS)

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The principal scientific objective of the Solar and Terrestrial Atmospheres Spectrometer (STAS) project is the measurement of the absolute ultraviolet solar spectral irradiance with: (1) resolution of better than 15 mA, and (2) absolute irradiance uncertainty at the state of the art (less than or equal to 3%). High measurement accuracy coupled with high spectral resolution are necessary to identify the nature of the radiation, its variability, and to identify solar processes which may cause the changes. Solar radiation between 1200 and 3600 A dominates the photochemistry of the mesosphere and stratosphere. Some important minor species, such as NO, show very complex and fundamentally narrow structure in their photodestruction cross sections, especially in the region of the Schumann-Runge bands of O2. Understanding the photochemical processes in the terrestrial atmosphere requires knowledge of both the cross sections and of the solar spectrum with the highest possible resolution and accuracy.

  1. Absorption of Solar Radiation by the Cloudy Atmosphere Interpretations of Collocated Aircraft Measurements

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.; Cess, Robert D.; Zhang, Minghua; Pope, Shelly K.; Bucholtz, Anthony; Bush, Brett; Vitko, John, Jr.

    1997-01-01

    As part of the Atmospheric Radiation Measurement (ARM) Enhanced Shortwave Experiment (ARESE), we have obtained and analyzed measurements made from collocated aircraft of the absorption of solar radiation within the atmospheric column between the two aircraft. The measurements were taken during October 1995 at the ARM site in Oklahoma. Relative to a theoretical radiative transfer model, we find no evidence for excess solar absorption in the clear atmosphere and significant evidence for its existence in the cloudy atmosphere. This excess cloud solar absorption appears to occur in both visible (0.224-0.68 microns) and near-infrared (0.68-3.30 microns) spectral regions, although not at 0.5 microns for the visible contribution, and it is shown to be true absorption rather than an artifact of sampling errors caused by measuring three-dimensional clouds.

  2. Variation of Acoustic Cutoff Period with Height in the Solar Atmosphere: Theory versus Observations

    NASA Astrophysics Data System (ADS)

    Murawski, K.; Musielak, Z. E.; Konkol, P.; Wiśniewska, A.

    2016-08-01

    Recently Wiśniewska et al. demonstrated observationally how the acoustic cutoff frequency varies with height in the solar atmosphere including the upper photosphere and the lower and middle chromosphere, and showed that the observational results cannot be accounted for by the existing theoretical formulas for the acoustic cutoff. In order to reproduce the observed variation of the cutoff with atmospheric height, numerical simulations of impulsively generated acoustic waves in the solar atmosphere are performed, and the spectral analysis of temporal wave profiles is used to compute numerically changes of the acoustic cutoff with height. Comparison of the numerical results with the observational data shows good agreement, which clearly indicates that the obtained results may be used to determine the structure of the background solar atmosphere.

  3. Analysis of Solar Cell Efficiency for Venus Atmosphere and Surface Missions

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Haag, Emily

    2013-01-01

    A simplified model of solar power in the Venus environment is developed, in which the solar intensity, solar spectrum, and temperature as a function of altitude is applied to a model of photovoltaic performance, incorporating the temperature and intensity dependence of the open-circuit voltage and the temperature dependence of the bandgap and spectral response of the cell. We use this model to estimate the performance of solar cells for both the surface of Venus and for atmospheric probes at altitudes from the surface up to 60 km. The model shows that photovoltaic cells will produce power even at the surface of Venus.

  4. The solar radiation incident at the top of the atmospheres of Uranus and Neptune

    NASA Astrophysics Data System (ADS)

    van Hemelrijck, E.

    1988-02-01

    The latitudinal and seasonal variation of the direct solar radiation incident at the top of the atmosphere of Uranus and Neptune has been recalculated by use of updated values for the period of axial rotation and the oblateness. Values for the solar radiation are given in watt per square meter instead of the unit used in earlier papers (calories per square centimeter per planetary day). The solar radiation averaged over a season and a year as a function of planetocentric latitude has also been reviewed. In addition, attention is paid to the ratio of the solar radiation incident on an oblate planet to that incident on a spherical planet.

  5. Ionization of the venusian atmosphere from solar and galactic cosmic rays

    NASA Astrophysics Data System (ADS)

    Nordheim, T. A.; Dartnell, L. R.; Desorgher, L.; Coates, A. J.; Jones, G. H.

    2015-01-01

    The atmospheres of the terrestrial planets are exposed to solar and galactic cosmic rays, the most energetic of which are capable of affecting deep atmospheric layers through extensive nuclear and electromagnetic particle cascades. In the venusian atmosphere, cosmic rays are expected to be the dominant ionization source below ∼100 km altitude. While previous studies have considered the effect of cosmic ray ionization using approximate transport methods, we have for the first time performed full 3D Monte Carlo modeling of cosmic ray interaction with the venusian atmosphere, including the contribution of high-Z cosmic ray ions (Z = 1-28). Our predictions are similar to those of previous studies at the ionization peak near 63 km altitude, but are significantly different to these both above and below this altitude. The rate of atmospheric ionization is a fundamental atmospheric property and the results of this study have wide-reaching applications in topics including atmospheric electrical processes, cloud microphysics and atmospheric chemistry.

  6. Correlation of Upper-Atmospheric Be-7 With Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Phillips, G. W.; Share, G. H.; August, R. A.; Tylka, A. J.; Adams, J. H., Jr.; Panasyuk, M. I.; Nymmik, R. A.; Kuzhevskjj, B. M.; Kulikauskas, V. S.; Rose, M. Franklin (Technical Monitor); Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Surprisingly large concentrations of radioactive Be-7 have been found in the upper atmosphere at levels of one to three orders of magnitude greater than observed in the stratosphere. This phenomenon was originally observed on the LDEF satellite which was recovered in January 1990 following a period of extremely high solar activity in the fall of 1989. We report on follow-up measurements on the Russian COSMOS and RESURS F1 spacecraft during the period of 1996 to 1999 which was a period of minimal to moderate solar activity. The Be-7 concentrations observed on these flights were down substantially from the LDEF observations but were still one to two orders of magnitude higher than stratospheric levels. A significant correlation is observed between the Be-7 activity and the combined fluence of solar energetic protons (SEP) and galactic cosmic-ray (GCR) protons. The Be-7 activity is not correlated with overall solar activity as represented by the solar x-ray flux. We discuss possible mechanisms for the solar proton correlation. However, it is likely that the Be-7 is ionized and it is unknown how this will affect the calculations. There were several large solar flares in the fall of 1989 that produced extraordinarily intense solar particle events at the Earth and record geophysical disturbances. These may have acted to increase production of Be-7 from spallation in the stratosphere and also to enhance transport to higher altitudes from the effects of heating and expansion of the upper atmosphere. Be-7 in the upper atmosphere may also have been produced directly at the Sun. Be-7 and Li-7 are produced in solar flares when accelerated alpha-particles fuse with He-4 in the solar atmosphere. Under optimistic assumptions for Sun to Earth transport and subsequent insertion into low Earth orbit, a Be-7 density of about 10(exp -7) atom/cubic cm at 310 km is estimated.

  7. On the dynamically driven temperature response in the middle atmosphere to the solar cycle signal.

    NASA Astrophysics Data System (ADS)

    Karlsson, Bodil; Kuilman, Maartje

    2016-04-01

    Noctilucent clouds (NLC), formed in the summer polar mesosphere, are exposed to solar radiation around the clock. These clouds consist of water ice, and are thus expected to be sensitive to changes in the solar Lyman alpha flux since it efficiently destroys water vapor in this region. Moreover, during solar maxima, the upper parts of the atmosphere are in general significantly warmer due to physical and chemical processes that are intensified at high solar activity. It is thus surprising that a clear solar cycle signal in NLC is hard to trace. We investigate how the circulation in the summer mesosphere is affected by changes in the solar flux using a 30-year run from the extended and nudged version of the Canadian Middle Atmosphere Model (CMAM30). We find that, as a result of a chain of wave-mean flow interactions primarily initiated in the winter stratosphere, the solar cycle signal from direct solar heating is suppressed by an enhanced circulation which adiabatically cools the region at increased solar activity.

  8. Realistic Modeling of Multi-Scale MHD Dynamics of the Solar Atmosphere

    NASA Technical Reports Server (NTRS)

    Kitiashvili, Irina; Mansour, Nagi N.; Wray, Alan; Couvidat, Sebastian; Yoon, Seokkwan; Kosovichev, Alexander

    2014-01-01

    Realistic 3D radiative MHD simulations open new perspectives for understanding the turbulent dynamics of the solar surface, its coupling to the atmosphere, and the physical mechanisms of generation and transport of non-thermal energy. Traditionally, plasma eruptions and wave phenomena in the solar atmosphere are modeled by prescribing artificial driving mechanisms using magnetic or gas pressure forces that might arise from magnetic field emergence or reconnection instabilities. In contrast, our 'ab initio' simulations provide a realistic description of solar dynamics naturally driven by solar energy flow. By simulating the upper convection zone and the solar atmosphere, we can investigate in detail the physical processes of turbulent magnetoconvection, generation and amplification of magnetic fields, excitation of MHD waves, and plasma eruptions. We present recent simulation results of the multi-scale dynamics of quiet-Sun regions, and energetic effects in the atmosphere and compare with observations. For the comparisons we calculate synthetic spectro-polarimetric data to model observational data of SDO, Hinode, and New Solar Telescope.

  9. Middle Atmosphere Program. Handbook for MAP, volume 29. Part 1: Extended Abstracts, International Symposium on Solar Activity Forcing of the Middle Atmosphere. Part 2: MASH Workshop

    NASA Technical Reports Server (NTRS)

    Lastovicka, Jan (Editor); Miles, Thomas (Editor); Oneill, Alan (Editor)

    1989-01-01

    The proceedings of the symposium is presented. Eight different sessions were presented: (1) Papers generally related to the subject; (2) Papers on the influence of the Quasi Biennial Oscillation; (3) Papers on the influence of the solar electromagnetic radiation variability; (4) Papers on the solar wind and high energy particle influence; (5) Papers on atmospheric circulation; (6) Papers on atmospheric electricity; (7) Papers on lower ionospheric variability; and (8) Solar posters, which are not included in this compilation.

  10. Surface Measurements of Solar Spectral Radiative Flux in the Cloud-Free Atmosphere

    NASA Technical Reports Server (NTRS)

    Pilewskie, Peter; Goetz, A. F. H.; Bergstrom, R.; Beal, D.; Gore, Warren J. Y. (Technical Monitor)

    1997-01-01

    Recent studies (Charlock, et al.; Kato, et. al) have indicated a potential discrepancy between measured solar irradiance in the cloud-free atmosphere and model derived downwelling solar irradiance. These conclusions were based primarily on broadband integrated solar flux. Extinction (both absorption and scattering) phenomena, however, typically have spectral characteristics that would be present in moderate resolution (e.g., 10 nm) spectra, indicating the need for such measurements to thoroughly investigate the cause of any discrepancies. The 1996 Department of Energy Atmospheric Radiation Measurement Program (ARM) Intensive Observation Period (IOP), held simultaneously with the NASA Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) Program, provided an opportunity for two simultaneous but independent measurements of moderate resolution solar spectral downwelling irradiance at the surface. The instruments were the NASA Ames Solar Spectral Flux Radiometer and the Analytical Spectral Devices, Inc., FieldSpecT-FR. Spectral and band integrated quantities from both sets of measurements will be presented, along with estimates of the downwelling solar irradiance from band model and line by line calculations, in an effort to determine the compatibility between measured and calculated solar irradiance in the cloud-free atmosphere.

  11. Pressure Sounding of the Middle Atmosphere from ATMOS Solar Occultation Measurements of Atmospheric CO(sub 2) Absorption Lines

    NASA Technical Reports Server (NTRS)

    Abrams, M.; Gunson, M.; Lowes, L.; Rinsland, C.; Zander, R.

    1994-01-01

    A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(sub 2) lines with temperature-insensitive intensities. Tangent pressures are determined with a spectroscopic precision of 1-3%, corresponding to a tangent point height precision, depending on the scale height, of 70-210 meters.

  12. Analysis of the variation of atmospheric electric field during solar events

    NASA Astrophysics Data System (ADS)

    Tacza, J.; Raulin, J. P.

    2016-12-01

    We present the capability of a new network of electric field mill sensors to monitor the atmospheric electric field at various locations in South America. The first task is to obtain a diurnal curve of atmospheric electric field variations under fair weather conditions, which we will consider as a reference curve. To accomplish this, we made daily, monthly, seasonal and annual averages. For all sensor location, the results show significant similarities with the Carnegie curve. The Carnegie curve is the characteristic curve in universal time of atmospheric electric field in fair weather and one thinks it is related to the currents flowing in the global atmospheric electric circuit. Ultimately, we pretend to study departures of the daily observations from the standard curve. This difference can be caused by solar, geophysical and atmospheric phenomena such as the solar activity cycle, solar flares and energetic charged particles, galactic cosmic rays, seismic activity and/or specific meteorological events. As an illustration we investigate solar effects on the atmospheric electric field observed at CASLEO (Lat. 31.798°S, Long. 69.295°W, Altitude: 2552 masl) by the method of superposed epoch analysis, between January 2010 and December 2015.

  13. Solar plages and the vorticity of the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Olson, R. H.; Roberts, W. O.; Prince, H. D.; Hedeman, E. R.

    1978-01-01

    Three superimposed epoch analyses of the vorticity area index (VAI) at 500 mbar are described. The analyses used the following definitions of the zero days: (1) the central meridian passage (CMP) of very active solar plages; (2) the occurrence of peak values of the 10.7 cm solar radio flux; and (3) the CMP of active solar plages also accompanied at CMP by sharp rises in 10.7 cm solar radio noise. All three superimposed epoch analyses show a sustained rise in VAI several days before the zero day; the rise continues through the zero day and is followed by a sustained minimum in VAI several days after the zero day. The results suggest that the location of the very active plages play an important role in determining their meteorological influence. It is possible that the initial rise in VAI is caused by enhanced electromagnetic radiation associated with the solar activity, and that the decrease some days later is the result of the geomagnetic storm particle emission that generally follows the zero date.

  14. The abundance of silicon in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Shaltout, A. M. K.; Beheary, M. M.; Bakry, A.; Ichimoto, K.

    2013-04-01

    High-resolution solar spectra were used to determine the silicon abundance (εSi) content by comparison with Si line synthesis relying on realistic hydrodynamical simulations of the solar surface convection, as 3D inhomogeneous model of the solar photosphere. Based on a set of 19 Si I and 2 Si II lines, with accurate transition probabilities as well as accurate observational data available, the solar photospheric Si abundance has been determined to be log εSi(3D) = 7.53 ± 0.07. Here we derive the photospheric silicon abundance taking into account non-LTE effects based on 1D solar model, the non-LTE abundance value we find is log εSi (1D) = 7.52 ± 0.08. The photospheric Si abundance agrees well with the results of Asplund and more recently published by Asplund et al. relative to previous 3D-based abundances, the consistency given that the quoted errors here are (±0.07 dex).

  15. Abundance analysis of neodymium in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Abdelkawy, Ali G. A.; Shaltout, Abdelrazek M. K.; Beheary, M. M.; Bakry, A.

    2017-10-01

    Based on non-local thermodynamical equilibrium (NLTE) calculations, the solar neodymium (Nd) content was found based on a model atom of singly ionized neodymium (Nd ii) containing 153 energy levels and 42 line transitions plus the ground state of Nd iii. Here, we re-derive the solar Nd abundance using the model of the solar photosphere of Holweger & Müller.We succeed in selecting a good sample line list, relying on 20 Nd ii solar lines together with the most accurate transition probabilities measured experimentally and available observational data. With damping parameters obtained from the literature, we find a mean NLTE solar photospheric Nd abundance of log ɛNd(1D) = 1.43 ± 0.16, which is in excellent agreement with the meteoritic value (log ɛNd = 1.45 ± 0.02). For a set of selected Nd ii lines, the NLTE abundance correction is found to be +0.01 dex compared with the standard LTE effect. The influence of collisional interactions with electrons and neutral hydrogen atoms is investigated in detail.

  16. Coupled Gas Giant Atmospheres: Solar Heating vs. Interior Heating

    NASA Astrophysics Data System (ADS)

    O'Neill, Morgan E.; Kaspi, Yohai; Galanti, Eli

    2015-11-01

    The weather layers of Jupiter and Saturn receive both solar radiation and heat from the deep interior. Currently, numerical models fall into two broad categories: deep, convecting interiors that lack an outer, solar-heated troposphere, or thin shells that represent only a troposphere, with parameterized heating from the lower boundary. Here we present results from a new coupled circulation model that allows deep convective plumes and columnar structures to interact with a stable troposphere that is heated by the sun. Equatorial superrotation, observed on Jupiter and Saturn, extends in axially-aligned columns from the deep interior through the troposphere. A tropospheric midlatitude baroclinic zone due to solar heating competes with the outer edges of the deep rotating columns to characterize midlatitude jet and temperature structure. We demonstrate this interplay between solar heating and interior heating in setting the strength and depth of the jets for a range of idealized gas giants. The relative impact of each is modulated by the static stability of the troposphere, which acts as a proxy for water abundance. We also show the impact of axial tilt, with respect to solar radiation, on asymmetries between the Northern and Southern hemispheres.

  17. The Potential for Solar Occultation Studies of the Atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Leblanc, L.; Drummond, J. R.; Walker, K. A.; Bernath, P.; Giroux, J.; Moreaux, L.

    2008-12-01

    Solar occultation infrared Fourier transform spectroscopy has been successfully applied to the study of the composition of the Earth's atmosphere by many instruments including the free-flying Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) and the shuttle-based Atmospheric Trace MOlecule Spectroscopy (ATMOS). However, looking beyond the Earth it is possible, with surprisingly few instrumental changes, to consider probing the atmosphere of other planets such as Mars. Elucidation of the present composition and isotopic nature of the atmosphere of Mars is relevant to studies of the planet, past and present; to the landing of future missions through better understanding of the atmosphere that these landers must pass through; and to the question of the presence of life on the planet, either now or at some time in the past. This paper will discuss the instrument and mission requirements as well as the science goals for an infrared Fourier transform spectrometer for investigating the atmospheric composition of Mars.

  18. On the importance of reverse current ohmic losses in electron-heated solar flare atmospheres

    NASA Technical Reports Server (NTRS)

    Emslie, A. G.

    1980-01-01

    The passage of a beam of nonthermal electrons through the flaring solar atmosphere is considered, paying particular attention to the requirement that the beam be stable to the generation of plasma turbulence. The ratio is computed of energy losses due to reverse current ohmic heating, and heating by Coulomb collisions, respectively, for the greatest flux which can pass stably through the atmosphere. It is demonstrated that this ratio is determined by the low energy cutoff of the beam, by the electron temperature of the ambient atmosphere, and by the electron to ion temperature ratio. It is also independent of the atmospheric density.

  19. SUMER: Temperatures, densities, and velocities in the outer solar atmosphere

    NASA Technical Reports Server (NTRS)

    Lemaire, Philippe; Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.; Grewing, M.; Huber, M. C. E.; Jordan, Stuart D.; Kuehne, M.; Marsch, Eckart

    1992-01-01

    The SUMER (Solar Ultraviolet Measurement of Emitted Radiation) instrumentation that will be mounted on the SOHO (Solar and Heliospheric Observatory) spacecraft is in development. It has some capability of improving the solar angular resolution and the spectral resolution already obtained in the far UV to the extreme UV, corresponding to the temperature range between 10,000 and a few 1,000,000 K. Some insights into the SUMER spectrometer, developed to study the dynamics and to infer temperatures and densities of the low corona and the chromosphere-corona transition zone in using the 50 to 160 nm wavelength range, are given. The SUMER scientific goals and the techniques used are outlined. The instrumentation and the expected performances are described. The way the observations can be conducted is emphasized and the operation of SUMER in coordination with other SOHO instrumentations and in cooperation with ground based observations is explained.

  20. The Response of High Energy Photoelectrons in The Mars Atmosphere to Variable Solar Input

    NASA Astrophysics Data System (ADS)

    Mills, I. F.; Eparvier, F. G.; Thiemann, E.; Mitchell, D. L.

    2016-12-01

    The Mars Atmosphere and Volatile Evolution (MAVEN) mission aims to understand the processes by which Mars has been losing atmosphere over time by analyzing data taken from different levels of the Martian atmosphere as well as solar drivers. In this project, we isolate data taken from the ionosphere to study high-energy electrons created by a particular ionization process called the Auger effect. This process occurs when soft x-rays ionize atmospheric gases. In particular, we focus on Auger electrons that are ionized from CO2 molecules and atomic O via solar irradiance in the 0.1-6 nm wavelength range. Thus far, the portion of the solar spectrum that produces Auger electrons has been sparsely measured and its spectral distribution is poorly understood, especially as a function of solar activity. To make up for this, models of spectral irradiance are used in studies of atmospheric effects. In an effort to validate solar irradiance models from 0.1- 6 nm, we utilize data from two instruments on board the MAVEN spacecraft, EUVM (the Extreme Ultraviolet Monitor), which measures the broadband solar irradiance from 0.1-6 nm and SWEA (the Solar Wind Electron Analyzer), which measures the photoelectron energy spectrum in the Mars atmosphere. We then compare these observed data sets to two different spectral irradiance models: MAVEN SynRef, and FISM-M (the Flare Irradiance Spectral Model for Mars). SynRef is a version of the SORCE XPS model modified to be used by MAVEN/EUVM, and FISM-M is a version of the FISM proxy model previously developed for Earth irradiance and modified to be used by MAVEN/EUVM. Our method of comparison is to find the Pearson correlation between the data and the models over October 2015, a month that had a strong solar rotational variability in the solar irradiance. By filtering the SWEA data for different altitudes and solar zenith angles, we are able to analyze how Auger electrons react under different solar activity levels. Both irradiance models

  1. Solar-Induced Fluorescence (SIF) Captured by California Laboratory for Atmospheric Remote Sensing (CLARS)

    NASA Astrophysics Data System (ADS)

    Xi, X.

    2015-12-01

    Solar-induced fluorescence (SIF) is emitted from the core of the photosynthetic apparatus and can serve as a direct indicator of photosynthetic efficiency. It could be exploited for large scale monitoring of plant health, which is crucial for studies in ecosystem, carbon cycle, agriculture, and other related fields. In this study, we use Fourier Transform Spectrometers at California Laboratory for Atmospheric Remote Sensing (CLARS) to measure high-resolution spectra near the oxygen A band. Measurement campaigns conducted in recent two years provide weeks of measurements that capture the diurnal variations of SIF from a variety of species including grasses and oak trees. Stationed on the top of Mount. Wilson in Southern California, CLARS is capable of monitoring SIF over the nearby mountains and the Los Angeles basin. This study aims to demonstrate that instruments at CLARS are capable of capturing SIF with high precision over different times of day. The high spatiotemporal variations of SIF are unique features of the CLARS measurements. The results have implications for the proposed constellation of geostationary satellites that are designed to capture SIF at regional scales.

  2. Effect of atmospheric scattering and surface reflection on upwelling solar radiation

    NASA Technical Reports Server (NTRS)

    Suttles, J. T.; Barkstrom, B. R.; Tiwari, S. N.

    1981-01-01

    A study is presented of the solar radiation transfer in the complete earth-atmosphere system, and numerical results are compared with satellite data obtained during the Earth Radiation Budget Experiment on Nimbus 6, in August, 1975. Emphasis is placed on the upwelling radiance distribution at the top of the atmosphere, assumed to be at 50 km. The numerical technique is based on the finite difference method, which includes azimuth and spectral variations for the entire solar wavelength range. Detailed solar properties, atmospheric physical properties, and optical properties are used. However, since the property descriptions are based on a trade-off between accuracy and computational realities, aerosol and cloud optical properties are treated with simple approximations. The radiative transfer model is in good agreement with the satellite radiance observations. The method provides a valuable tool in analyzing satellite- and ground-based radiation budget measurements and in designing instrumentation.

  3. The atmospheric cosmic- and solar energetic particle radiation environment at aircraft altitudes.

    PubMed

    O'Brien, K; Friedberg, W; Smart, D F; Sauer, H H

    1998-01-01

    Galactic cosmic rays interact with the solar wind, the earth's magnetic field and hadron, lepton and photon fields at aircraft altitudes. In addition to cosmic rays, energetic particles generated by solar activity bombard the earth from time to time. These particles, while less energetic than cosmic rays, also produce radiation fields at aircraft altitudes which have qualitatively the same properties as atmospheric cosmic rays. We have used a code based on transport theory to calculate atmospheric cosmic-ray quantities and compared them with experimental data. Agreement with these data is seen to be good. We have then used this code to calculate equivalent doses to aircraft crews. We have also used the code to calculate radiation doses from several large solar energetic particle events which took place in 1989, including the very large event that occurred on September 29th and 30th of that year. The spectra incident on the atmosphere were determined assuming diffusive shock theory.

  4. Solar spectral irradiance variation and its impact on earth's atmosphere as observed by SCIAMACHY

    NASA Astrophysics Data System (ADS)

    Weber, M.; Pagaran, J.; Burrows, J. P.; Dikty, S.; von Savigny, C.; DeLand, M. T.; Floyd, L. E.; Harder, J. W.; Langematz, U.

    2011-12-01

    SCIAMACHY is a UV/vis/NIR spectrometer aboard ENVISAT which provides routine observations of ozone and other trace gases in the earth's atmosphere since 2002. Ozone profile data are provided from limb, lunar, and solar occultation observations, while the nadir viewing geometry allows measurements of total ozone columns. For normalizing observed backscattered earth radiances for trace gas retrievals, daily measurements of solar irradiance at moderately high spectral resolution (<1.5 nm) from 230 nm to 2400 nm, with some gaps in the NIR, are made. From the solar observations a Mg II index can be derived that in combination with other satellite data becomes a useful solar UV activity proxy indicator during the satellite era (since 1978). Using solar proxies for faculae brightening and sunspot darkening fitted to SCIAMACHY irradiance time-series a SCIA proxy model has been derived that allows us to describe solar cycle irradiance changes covering several decades. This talk will present highlights from SCIAMACHY solar observations, comparisons with other satellite data, and presents results on solar influence on ozone, i. e. 27 day solar rotation signal in the upper stratosphere and solar cycle effects on polar ozone losses.

  5. Atmospheric escape due to solar wind interaction: Recent results from Mars and Venus Express

    NASA Astrophysics Data System (ADS)

    Barabash, S.; Fedorov, A.

    2008-09-01

    Abstract Non-magnetized planets lose their atmospheres due to interaction with the solar wind. The atmospheric gasses are ionized and a fraction of the ions is accelerated to velocities above the escape velocity by, for example, convectional electric fields, polarization fields, or as result of plasma instabilities at the interface boundary. We review the recent results from the plasma packages onboard ESA Mars and Venus Express on the escape rates from Mars and Venus for the solar minimum conditions. We also compare these new data with the previous measurements at Mars and Venus for the solar maximum as well as with the escape due to the solar wind interaction with the magnetized planet Earth.

  6. Observational Test for the Solar Wind Sputtering Origin of the Moon's Extended Sodium Atmosphere

    NASA Astrophysics Data System (ADS)

    Mendillo, Michael; Baumgardner, Jeffrey; Wilson, Jody

    1999-01-01

    We present observations of the lunar sodium atmosphere during four lunar eclipses between 1993 and 1997. With the Moon inside the magnetosphere, and therefore shielded from solar wind impact, we find its Na atmosphere to be comparable in abundance to cases near first and third quarter, implying that solar wind ion sputtering is not a significant source of the atmosphere. The atmosphere is azimuthally symmetric, and it extends beyond the field of view of our observations (∼12 Lunar radii). The average sodium atmospheric profile is best characterized by anr-1.4radial power law, close to that for an entirely escaping atmosphere. The average extrapolated near-surface brightness of 1145 rayleighs is in agreement with the near-surface polar brightness seen at quarter Moon. This corresponds to a line-of-sight neutral column content of 1.4×109Na atoms cm-2above the limb and a density of ∼3 atoms cm-3above the surface, decreasing asr-2.4. We suggest that a blend of sources (15% micrometeor impact uniform over the surface and 85% photon-induced desorption dependent on solar-zenith angle over the sunlit hemisphere) could account for the observed extended sodium atmospheres.

  7. Lower and middle atmosphere and ozone layer responses to solar variation

    NASA Astrophysics Data System (ADS)

    Elias, Ana G.

    2010-02-01

    Global warming in the troposphere and the decrease of stratospheric ozone concentration has become a major concern to the scientific community. The increase in greenhouse gases and aerosols concentration is believed to be the main cause of this global change in the lower atmosphere and in stratospheric ozone, which is corresponded by a cooling in the middle and upper atmosphere. However, there are natural sources, such as the sun and volcanic eruptions, with the same ability to produce global changes in the atmosphere. The present work will focus on solar variation and its signature in lower and middle atmosphere parameters. The Sun can influence the Earth and its climate through electromagnetic radiation variations and also through changes in the solar wind which causes geomagnetic storms. The effects of both mechanisms over the lower and middle atmosphere and ozone layer will be discussed through an overview of selected papers, which by no means cover this subject that is extremely wide and complex. A fundamental understanding of the atmosphere response to solar variations is required for understanding and interpreting the causes of atmospheric variability. This is an essential focus of climate science, which is seeking to determine the extent to which human activities are altering the planetary energy balance through the emission of greenhouse gases and pollutants.

  8. Retrieval of upper atmosphere pressure-temperature profiles from high resolution solar occultation spectra

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Russell, J. M., III; Park, J. H.; Namkung, J.

    1987-01-01

    Pressure-temperature profiles over the 18 to 75 km altitude range were retrieved from 0.01 cm(-1) resolution infrared solar absorption spectra recorded with the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer operating in the solar occultation mode during the Spacelab 3 shuttle mission (April 30 to May 1, 1985). The analysis method is described and preliminary results deduced for five occultation events are compared to correlative pressure-temperature measurments.

  9. Atmospheric extinction in solar tower plants: the Absorption and Broadband Correction for MOR measurements

    NASA Astrophysics Data System (ADS)

    Hanrieder, N.; Wilbert, S.; Pitz-Paal, R.; Emde, C.; Gasteiger, J.; Mayer, B.; Polo, J.

    2015-05-01

    Losses of reflected Direct Normal Irradiance due to atmospheric extinction in concentrating solar tower plants can vary significantly with site and time. The losses of the direct normal irradiance between the heliostat field and receiver in a solar tower plant are mainly caused by atmospheric scattering and absorption by aerosol and water vapor concentration in the atmospheric boundary layer. Due to a high aerosol particle number, radiation losses can be significantly larger in desert environments compared to the standard atmospheric conditions which are usually considered in raytracing or plant optimization tools. Information about on-site atmospheric extinction is only rarely available. To measure these radiation losses, two different commercially available instruments were tested and more than 19 months of measurements were collected at the Plataforma Solar de Almería and compared. Both instruments are primarily used to determine the meteorological optical range (MOR). The Vaisala FS11 scatterometer is based on a monochromatic near-infrared light source emission and measures the strength of scattering processes in a small air volume mainly caused by aerosol particles. The Optec LPV4 long-path visibility transmissometer determines the monochromatic attenuation between a light-emitting diode (LED) light source at 532 nm and a receiver and therefore also accounts for absorption processes. As the broadband solar attenuation is of interest for solar resource assessment for Concentrating Solar Power (CSP), a correction procedure for these two instruments is developed and tested. This procedure includes a spectral correction of both instruments from monochromatic to broadband attenuation. That means the attenuation is corrected for the actual, time-dependent by the collector reflected solar spectrum. Further, an absorption correction for the Vaisala FS11 scatterometer is implemented. To optimize the Absorption and Broadband Correction (ABC) procedure, additional

  10. Ellerman bombs—evidence for magnetic reconnection in the lower solar atmosphere

    SciTech Connect

    Nelson, C. J.; Doyle, J. G.; Madjarska, M. S.; Shelyag, S.; Mathioudakis, M.; Uitenbroek, H.; Erdélyi, R.

    2013-12-20

    The presence of photospheric magnetic reconnection has long been thought to give rise to short and impulsive events, such as Ellerman bombs (EBs) and Type II spicules. In this article, we combine high-resolution, high-cadence observations from the Interferometric BIdimensional Spectrometer and Rapid Oscillations in the Solar Atmosphere instruments at the Dunn Solar Telescope, National Solar Observatory, New Mexico, with co-aligned Solar Dynamics Observatory Atmospheric Imaging Assembly and Hinode Solar Optical Telescope (SOT) data to observe small-scale events situated within an active region. These data are then compared with state-of-the-art numerical simulations of the lower atmosphere made using the MURaM code. It is found that brightenings, in both the observations and the simulations, of the wings of the Hα line profile, interpreted as EBs, are often spatially correlated with increases in the intensity of the Fe I λ6302.5 line core. Bipolar regions inferred from Hinode/SOT magnetic field data show evidence of flux cancellation associated, co-spatially, with these EBs, suggesting that magnetic reconnection could be a driver of these high-energy events. Through the analysis of similar events in the simulated lower atmosphere, we are able to infer that line profiles analogous to the observations occur co-spatially with regions of strong opposite-polarity magnetic flux. These observed events and their simulated counterparts are interpreted as evidence of photospheric magnetic reconnection at scales observable using current observational instrumentation.

  11. Effects of the March 2015 solar eclipse on near-surface atmospheric electricity.

    PubMed

    Bennett, A J

    2016-09-28

    Measurements of atmospheric electrical and standard meteorological parameters were made at coastal and inland sites in southern England during the 20 March 2015 partial solar eclipse. Clear evidence of a reduction in air temperature resulting from the eclipse was found at both locations, despite one of them being overcast during the entire eclipse. The reduction in temperature was expected to affect the near-surface electric field (potential gradient (PG)) through a reduction in turbulent transfer of space charge. No such effect could be unambiguously confirmed, however, with variability in PG and air-Earth current during the eclipse being comparable to pre- and post-eclipse conditions. The already low solar radiation for this latitude, season and time of day was likely to have contributed to the reduced effect of the eclipse on atmospheric electricity through boundary layer stability. The absence of a reduction in mean PG shortly after time of maximum solar obscuration, as observed during eclipses at lower geomagnetic latitude, implied that there was no significant change in atmospheric ionization from cosmic rays above background variability. This finding was suggested to be due to the relative importance of cosmic rays of solar and galactic origin at geomagnetic mid-latitudes.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'.

  12. Magnetic coupling of waves and oscillations in the lower solar atmosphere: can the tail wag the dog?

    PubMed

    Erdélyi, Robert

    2006-02-15

    Can the ubiquitously magnetic solar atmosphere have any effect on solar global oscillations? Traditionally, solar atmospheric magnetic fields are considered to be somewhat less important for the existence and characteristic features of solar global oscillations (p,f and the not-yet-observed g-modes). In this paper, I demonstrate the importance of the presence of magnetism and plasma dynamics for global resonant oscillations in the solar atmosphere. In particular, in the lower part of the solar atmosphere there are both coherent and random components of magnetic fields and velocity fields, each of which contribute on its own to the line widths and frequency variations of solar global acoustic waves. Changes in the coherent large-scale atmospheric magnetic fields cause frequency shifts of global oscillations over a solar cycle. The random character of the continuously emerging, more localized, magnetic carpet (i.e. small-scale, possibly even sub-resolution, loops) gives rise to additional frequency shifts. On the other hand, random and organized surface and sub-surface flows, like surface granulation, meridional flows or differential rotation, also affect the coupling mechanism of global oscillations to the lower magnetic atmosphere. The competition between magnetic fields and flows is inevitable. Finally, I shall discuss how solar global oscillations can resonantly interact with the overlaying inhomogeneous lower solar atmosphere embedded in a magnetic carpet. Line width broadening and distorsion of global acoustic modes will be discussed. The latter is suggested to be tested and measured by using ring-analysis techniques.

  13. On the heating mechanism of magnetic flux loops in the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Song, M. T.; Wu, S. T.

    1984-01-01

    An investigation is conducted of physical heating mechanisms due to the ponderomotive forces exerted by turbulent waves along the solar atmosphere's curved magnetic flux loops. Results indicate that the temperature difference between the inside and outside of the flux loop can be classified into three parts, two of which represent the cooling or heating effect exerted by the ponderomotive force, while the third is the heating effect due to turbulent energy conversion from the localized plasma. This heating mechanism is used to illustrate solar atmospheric heating by means of an example that leads to the formulation of plages.

  14. Seasonal north-south asymmetry in solar radiation at the top of Jupiter's atmosphere

    NASA Technical Reports Server (NTRS)

    Beebe, R.; Suggs, R.

    1986-01-01

    A selected set of planetocentric latitudes is used in calculations of the seasonal solar radiation pattern incident on top of the Jovian atmosphere, thereby demonstrating the combined effect of solar distance and declination. Attention is given to hemispheric asymmetries in the Jovian atmosphere's average zonal winds and cloud system morphologies. Marked hemispheric asymmetries are noted in the cloud morphology and in the magnitude and latitudinal position of eastward and westward maxima in the average zonal winds, suggesting seasonal forcing on the order of magnitude presently considered. Supporting observations by Voyagers 1 and 2 are cited.

  15. 3-d modeling of the middle and upper atmosphere response to the 27-day solar variation

    NASA Astrophysics Data System (ADS)

    Gruzdev, A.; Schmidt, H.; Brasseur, G.

    We present results of an analysis of the effect of the 27-day solar variation on composition and temperature of the stratosphere mesosphere and lower thermosphere calculated with the 3-dimensional chemistry climate model HAMMONIA The spectral amplitudes of the 27-day solar cycle within the wavelength range from Lyman-a to the short infrared which are input parameters at the upper boundary of the model were calculated from data of UARS SOLSTICE measurements A combination of high resolution spectral and cross-spectral analyses allows determining 27-day variations in the Earth atmosphere which are related to the 27-day solar forcing These methods give also estimates of the amplitude and hence sensitivity and phase of the response While the calculated thermal and chemical responses are very distinct and permanent in the upper atmosphere the responses in the stratosphere and mesosphere are intermittent in time and affected as well by interannual variability It is due to interference of the inherent atmospheric variability and the variability forced by the 27-day solar cycle which sophisticates the response to the 27-day solar forcing in large parts of the model stratosphere and mesosphere In the extratropical latitudes the responses are seasonally dependent Altitude-latitude distributions of sensitivities and phases of the responses to the 27-day solar forcing are analyzed in detail for temperature and chemical species important for ozone chemistry The sensitivity and phase of the ozone response in the tropical stratosphere and lower mesosphere are in satisfactory

  16. Solar Cycle Variability in Mean Thermospheric Composition and Temperature Induced by Atmospheric Tides

    NASA Astrophysics Data System (ADS)

    Jones, M., Jr.; Forbes, J. M.; Hagan, M. E.

    2015-12-01

    Vertically-propagating atmospheric thermal tides whose origins lie in Earth's lower atmosphere are now widely recognized as one of the dominant "meteorological" drivers of space weather. Many prior research efforts have focused on documenting and understanding the role that dissipating tides play in determining the longitudinal and seasonal variability associated with lower thermospheric winds, temperature, and constituent densities. However, considerably less attention has focused on understanding the potential solar cycle variability in the mean thermospheric state induced by the tides. In this paper we utilize the National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM), forced with observationally-based tides at the model lower boundary from the Climatological Tidal Model of the Thermosphere (CTMT, from Oberheide et al. [2011]), to elucidate how the dissipating tides induce variations of up to 30 K in the zonal-mean thermosphere temperature between solar minimum and maximum. Numerical experiments are performed for the month of September and for solar minimum, medium, and maximum conditions in order to quantify the solar cycle variability associated with the different terms in the thermodynamic energy, major and minor neutral constituent continuity equations. Our analysis indicates that solar cycle variability in neutral temperatures results from a combination of net eddy heat transport effects and tidal modulation of net nitric oxide (NO) cooling. The chemical and dynamical pathways through which dissipating tides affect mean NO cooling differently at solar minimum and maximum are diagnosed.

  17. Short- and Medium-term Atmospheric Effects of Very Large Solar Proton Events

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Marsh, Daniel R.; Vitt, Francis M.; Garcia, Rolando R.; Fleming, Eric L.; Labow, Gordon J.; Randall, Cora E.; Lopez-Puertas, Manuel; Funke, Bernd

    2007-01-01

    Long-term variations in ozone have been caused by both natural and humankind related processes. In particular, the humankind or anthropogenic influence on ozone from chlorofluorocarbons and halons (chlorine and bromine) has led to international regulations greatly limiting the release of these substances. These anthropogenic effects on ozone are most important in polar regions and have been significant since the 1970s. Certain natural ozone influences are also important in polar regions and are caused by the impact of solar charged particles on the atmosphere. Such natural variations have been studied in order to better quantify the human influence on polar ozone. Large-scale explosions on the Sun near solar maximum lead to emissions of charged particles (mainly protons and electrons), some of which enter the Earth's magnetosphere and rain down on the polar regions. "Solar proton events" have been used to describe these phenomena since the protons associated with these solar events sometimes create a significant atmospheric disturbance. We have used the National Center for Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM) to study the short- and medium-term (days to a few months) influences of solar proton events between 1963 and 2005 on stratospheric ozone. The four largest events in the past 45 years (August 1972; October 1989; July 2000; and October-November 2003) caused very distinctive polar changes in layers of the Earth's atmosphere known as the stratosphere (12-50 km; -7-30 miles) and mesosphere (50-90 km; 30-55 miles). The solar protons connected with these events created hydrogen- and nitrogen- containing compounds, which led to the polar ozone destruction. The hydrogen-containing compounds have very short lifetimes and lasted for only a few days (typically the duration of the solar proton event). On the other hand, the nitrogen-containing compounds lasted much longer, especially in the Winter. The nitrogen oxides were predicted

  18. Mars atmospheric losses induced by the solar wind: current knowledge and perspective

    NASA Astrophysics Data System (ADS)

    Ermakov, V.; Zelenyi, L. M.; Vaisberg, O. L.; Dubinin, E.

    2016-12-01

    Solar wind induced atmospheric losses have been studied since earlier 1970th. Several loss channels have been identified including pick-up of exospheric photo-ions and ionospheric ions escape. Measurements performed during several solar cycles showed variation of these losses by about factor of 10, being largest at maximum solar activity. Maven spacecraft equipped with comprehensive set of instruments with high temporal resolution operating at Mars since fall 2014 ensures much better understanding of solar wind enforcing of Martian environment, Mars atmospheric losses processes and mass loss rate. These issues are very important for understanding of Martian atmospheric evolution including water loss during cosmogonic time. Simultaneous observations by MAVEN and MEX spacecraft open the new perspective in study of Martian environment. In this report we discuss results of past and current missions in terms of atmospheric loss processes and loss rate in context of time history of Martian atmosphere including open issues. This work was supported by Russian Science Foundation (grant Nr.16-42-01103).

  19. Atmospheric Mining in the Outer Solar System: Resource Capturing, Storage, and Utilization

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2014-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as helium 3 and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate for hydrogen helium 4 and helium 3, storage options, and different methods of direct use of the captured gases. Additional supporting analyses were conducted to illuminate vehicle sizing and orbital transportation issues.

  20. Atmospheric Mining in the Outer Solar System: Resource Capturing, Storage, and Utilization

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2012-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate for hydrogen helium 4 and helium 3, storage options, and different methods of direct use of the captured gases. Additional supporting analyses were conducted to illuminate vehicle sizing and orbital transportation issues.

  1. Atmospheric chemistry of carboxylic acids: microbial implication versus photochemistry

    NASA Astrophysics Data System (ADS)

    Vaïtilingom, M.; Charbouillot, T.; Deguillaume, L.; Maisonobe, R.; Parazols, M.; Amato, P.; Sancelme, M.; Delort, A.-M.

    2011-02-01

    Clouds are multiphasic atmospheric systems in which the dissolved organic compounds, dominated by carboxylic acids, are subject to multiple chemical transformations in the aqueous phase. Among them, solar radiation, by generating hydroxyl radicals (•OH), is considered as the main catalyzer of the reactivity of organic species in clouds. We investigated to which extent the active biomass existing in cloud water represents an alternative route to the chemical reactivity of carboxylic acids. Pure cultures of seventeen bacterial strains (Arthrobacter, Bacillus, Clavibacter, Frigoribacterium, Pseudomonas, Sphingomonas and Rhodococcus), previously isolated from cloud water and representative of the viable community of clouds were first individually incubated in two artificial bulk cloud water solutions at 17 °C and 5 °C. These solutions mimicked the chemical composition of cloud water from "marine" and "continental" air masses, and contained the major carboxylic acids existing in the cloud water (i.e. acetate, formate, succinate and oxalate). The concentrations of these carboxylic compounds were monitored over time and biodegradation rates were determined. In average, they ranged from 2 ×10-19 for succinate to 1 × 10-18 mol cell-1 s-1 for formate at 17 °C and from 4 × 10-20 for succinate to 6 × 10-19 mol cell-1 s-1 for formate at 5 °C, with no significant difference between "marine" and "continental" media. In parallel, irradiation experiments were also conducted in these two artificial media to compare biodegradation and photodegradation of carboxylic compounds. To complete this comparison, the photodegradation rates of carboxylic acids by •OH radicals were calculated from literature data. Inferred estimations suggested a significant participation of microbes to the transformation of carboxylic acids in cloud water, particularly for acetate and succinate (up to 90%). Furthermore, a natural cloud water sample was incubated (including its indigenous microflora

  2. Photochemical hazes in planetary atmospheres: solar system bodies and beyond

    NASA Astrophysics Data System (ADS)

    Imanaka, Hiroshi; Cruikshank, Dale P.; McKay, Christopher P.

    2015-11-01

    Recent transit observations of exoplanets have demonstrated the possibility of a wide prevalence of haze/cloud layers at high altitudes. Hydrocarbon photochemical haze could be the candidate for such haze particles on warm sub-Neptunes, but the lack of evidence for methane poses a puzzle for such hydrocarbon photochemical haze. The CH4/CO ratios in planetary atmospheres vary substantially from their temperature and dynamics. An understanding of haze formation rates and plausible optical properties in a wide diversity of planetary atmospheres is required to interpret the current and future observations.Here, we focus on how atmospheric compositions, specifically CH4/CO ratios, affect the haze production rates and their optical properties. We have conducted a series of cold plasma experiments to constrain the haze mass production rates from gas mixtures of various CH4/CO ratios diluted either in H2 or N2 atmosphere. The mass production rates in the N2-CH4-CO system are much greater than those in the H2-CH4-CO system. They are rather insensitive to the CH4/CO ratios larger than at 0.3. Significant formation of solid material is observed both in H2-CO and N2-CO systems without CH4 in the initial gas mixtures. The complex refractive indices were derived for haze samples from N2-CH4, H2-CH4, and H2-CO gas mixtures. These are the model atmospheres for Titan, Saturn, and exoplanets, respectively. The imaginary part of the complex refractive indices in the UV-Vis region are distinct among these samples, which can be utilized for modeling these planetary atmospheres.

  3. Atmospheric Sensitivity to Spectral Top-of-Atmosphere Solar Irradiance Perturbations, Using MODTRAN-5 Radiative Transfer Algorithm

    NASA Astrophysics Data System (ADS)

    Anderson, G.; Berk, A.; Harder, G.; Fontenla, J.; Shettle, E.; Pilewski, P.; Kindel, B.; Chetwynd, J.; Gardner, J.; Hoke, M.; Jordan, A.; Lockwood, R.; Felde, G.; Archarya, P.

    2006-12-01

    The opportunity to insert state-of-the-art solar irradiance measurements and calculations, with subtle perturbations, into a narrow spectral resolution radiative transfer model has recently been facilitated through release of MODTRAN-5 (MOD5). The new solar data are from: (1) SORCE satellite measurements of solar variability over solar rotation cycle, & (2) ultra-narrow calculation of a new solar source irradiance, extending over the full MOD5 spectral range, from 0.2 um to far-IR. MODTRAN-5, MODerate resolution radiance and TRANsmittance code, has been developed collaboratively by Air Force Research Laboratory and Spectral Sciences, Inc., with history dating back to LOWTRAN. It includes approximations for all local thermodynamic equilibrium terms associated with molecular, cloud, aerosol and surface components for emission, scattering, and reflectance, including multiple scattering, refraction and a statistical implementation of Correlated-k averaging. The band model is based on 0.1 cm-1 (also 1.0, 5.0 and 15.0 cm-1 statistical binning for line centers within the interval, captured through an exact formulation of the full Voigt line shape. Spectroscopic parameters are from HITRAN 2004 with user-defined options for additional gases. Recent validation studies show MOD5 replicates line-by-line brightness temperatures to within ~0.02ºK average and <1.0ºK RMS. MOD5 can then serve as a surrogate for a variety of perturbation studies, including the two modes for the solar source function, Io. (1) Data from the Solar Radiation and Climate Experiment (SORCE) satellite mission provide state-of-the-art measurements of UV, visible, near-IR, plus total solar radiation, on near real-time basis. These internally consistent estimates of Sun's output over solar rotation and longer time scales are valuable inputs for studying effects of Sun's radiation on Earth's atmosphere and climate. When solar rotation encounters bright plage and dark sunspots, relative variations are

  4. Atmospheric effects on solar-cell calibration and evaluation

    SciTech Connect

    Bird, R.E.; Hulstrom, R.L.

    1981-12-01

    Results are presented that illustrate atmospheric effects on cell short currents and calibration numbers for silicon, gallium arsenide, and cadmium sulfide cells. Rigorous radiative transfer codes are used in this analysis to illustrate the effects of precipitable water, turbidity, air mass, and global normal irradiance compared with direct normal irradiance on cell performance. Precipitable water is shown to have a relatively large effect on GaAs (5%) as compared to a small effect (2%) on other cells. The quantitative effects of air mass and turbidity are illustrated. It was found that under some atmospheric conditions global calibration methods have a greater dependence on air mass than direct normal calibrations methods.

  5. DOT tomography of the solar atmosphere. I. Telescope summary and program definition

    NASA Astrophysics Data System (ADS)

    Rutten, R. J.; Hammerschlag, R. H.; Bettonvil, F. C. M.; Sütterlin, P.; de Wijn, A. G.

    2004-01-01

    The Dutch Open Telescope (DOT) on La Palma is an innovative optical solar telescope capable of reaching 0.2 arcsec angular resolution over extended durations. The DOT presently progresses from technology testbed to a stable science configuration providing multi-wavelength imaging and multi-camera speckle data acquisition for tomographic mapping of the solar atmosphere. Large-volume speckle processing will soon enable frequent usage and community-wide time allocation, in particular for tandem operation with other solar telescopes pursuing spectropolarimetry and EUV imaging. We summarize the DOT hardware and software in the context of this increasing availability and outline the corresponding ``open-DOT'' program.

  6. Global three-neutrino vacuum oscillation fits to the solar and atmospheric anomalies

    SciTech Connect

    Barger, V. |; Whisnant, K.

    1999-05-01

    We determine the three-neutrino mixing and mass parameters that are allowed by the solar and atmospheric neutrino data when vacuum oscillations are responsible for both phenomena. The global fit does not appreciably change the allowed regions for the parameters obtained from effective two-neutrino fits. We discuss how measurements of the solar electron energy spectrum below 6.5 GeV in Super-Kamiokande and seasonal variations in the Super-Kamiokande, {sup 71}Ga, and BOREXINO experiments can distinguish the different solar vacuum solutions. {copyright} {ital 1999} {ital The American Physical Society}

  7. Dynamics of the atmospheric boundary layer during the 1980 total solar eclipse

    SciTech Connect

    SethuRaman, S

    1981-01-01

    An atmospheric boundary layer experiment was conducted at Raichur, India to study the variations in the surface shear stress, heat flux and the meteorological processes that take place during a total solar eclipse. Interesting results were observed regarding the evolution of the planetary boundary layer. Changes in atmospheric stability from unstable to stable to unstable were observed during different phases of the eclipse. Downward propagation of negative heat flux associated with decreasing scales of convective eddies was also observed during the eclipse.

  8. A parameterization for the absorption of solar radiation by water vapor in the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Wang, W.-C.

    1976-01-01

    A parameterization for the absorption of solar radiation as a function of the amount of water vapor in the earth's atmosphere is obtained. Absorption computations are based on the Goody band model and the near-infrared absorption band data of Ludwig et al. A two-parameter Curtis-Godson approximation is used to treat the inhomogeneous atmosphere. Heating rates based on a frequently used one-parameter pressure-scaling approximation are also discussed and compared with the present parameterization.

  9. Instrument development for atmospheric radiation measurement (ARM): Status of the Atmospheric Emitted Radiance Interferometer - extended Resolution (AERI-X), the Solar Radiance Transmission Interferometer (SORTI), and the Absolute Solar Transmission Inferometer (ASTI)

    SciTech Connect

    Murcray, F.; Stephen, T.; Kosters, J.

    1996-04-01

    This paper describes three instruments currently under developemnt for the Atmospheric Radiation Measurement (ARM) Program at the University of Denver: the AERI-X (Atmospheric Emitted Radiance Interferometer-Extended Resolution) and the SORTI (Solar R adiance Transmission Interferometer), and ASTI (Absolute Solar transmission Interferometer).

  10. A Comparison among Solar Diameter Measurements Carried Out from the Ground and outside Earth's Atmosphere

    NASA Astrophysics Data System (ADS)

    Djafer, D.; Thuillier, G.; Sofia, S.

    2008-03-01

    The solar diameter has been measured since the 17th century, using different methods and instruments, and without a clear strategy of measurement, which could explain the lack of coherence between the results obtained. The present study confirms that the discrepancies between solar diameter measurements are mostly due to differences in instrumental characteristics, the spectral domain of observation of each investigation, and atmospheric turbulence for ground measurements. We show that correcting the measurements for the effects introduced by the properties of each instrument reduces the differences between the radius measurements to the level of uncertainty of each instrument. This study makes use of simulated and real data. For the simulated data, we use an empirical model of the solar limb shape, and for observations, we use measurements carried out with the Solar Disk Sextant experiment, the CCD solar astrolabe of Calern Observatory, and the Michelson Doppler Imager on board SOHO.

  11. Magnetic Energy Storage and Conversion in the Solar Atmosphere.

    DTIC Science & Technology

    1981-07-01

    in the quasi-equilibrium loop is by localizing heating, which causes both hydromagnetic expansion perpendicular to the magnetic field and hydrodynamic ...on s*.o ide it necessary and Idenity by bl. k .-. be,) Solar Flares Magnetohydrodyn,-imic Stability Pre-Flare Energy Storage Double Layers Flare...storage process and the macroscopic stability of those plasma-magnetic field configurations in which this storage might occur. We first review how currents

  12. GOME wavelength calibration using solar and atmospheric spectra

    NASA Technical Reports Server (NTRS)

    Caspar, C.; Chance, K.

    1997-01-01

    Spectral information in the global ozone monitoring experiment (GOME) solar irradiance spectra and GOME earth radiance spectra are used in conjunction with the GOME solar reference spectrum to provide absolute vacuum internal wavelength calibration for GOME. Two methods for wavelength calibration of GOME data are investigated. The first employs chi-square minimization of a merit function involving wavelength and the GOME slit function. It is quite robust and requires little GOME data in the processing (calibration window regions from 15 to 40 pixels). The second employs cross correlation of GOME data and the solar reference spectrum in the Fourier transform domain, using a procedure in the image reduction and analysis facility (IRAF) software system developed for the determination of galaxy redshifts. It also requires small amounts of GOME data (calibration window regions with from 10 to 15 pixels). Both methods provide absolute wavelength calibration accurate to a small fraction of a GOME pixel across the entire GOME spectrum, and to 0.001 nm over much of the range.

  13. Atmospheric Mining in the Outer Solar System:. [Aerial Vehicle Reconnaissance and Exploration Options

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    2014-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate, storage options, and different methods of direct use of the captured gases. Additional supporting analyses were conducted to illuminate vehicle sizing and orbital transportation issues. While capturing 3He, large amounts of hydrogen and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of additional exploration and exploitation vehicles exists. Additional aerospacecraft or other aerial vehicles (UAVs, balloons, rockets, etc.) could fly through the outer planet atmospheres, for global weather observations, localized storm or other disturbance investigations, wind speed measurements, polar observations, etc. Deep-diving aircraft (built with the strength to withstand many atmospheres of pressure) powered by the excess hydrogen or helium 4 may be designed to probe the higher density regions of the gas giants. Outer planet atmospheric properties, atmospheric storm data, and mission planning for future outer planet UAVs are presented.

  14. Solar XUV and ENA-driven water loss from early Venus' steam atmosphere

    NASA Astrophysics Data System (ADS)

    Lichtenegger, H. I. M.; Kislyakova, K. G.; Odert, P.; Erkaev, N. V.; Lammer, H.; Gröller, H.; Johnstone, C. P.; Elkins-Tanton, L.; Tu, L.; Güdel, M.; Holmström, M.

    2016-05-01

    We present a study on the influence of the upper atmosphere hydrodynamic escape of hydrogen, driven by the solar soft X-ray and extreme ultraviolet radiation (XUV), on an expected outgassed steam atmosphere of early Venus. By assuming that the young Sun was either a weak or moderately active young G star, we estimated the water loss from a hydrogen dominated thermosphere due to the absorption of the solar XUV flux and the precipitation of solar wind produced energetic hydrogen atoms (ENAs). The production of ENAs and their interaction with the hydrodynamic extended upper atmosphere, including collision-related feedback processes, have been calculated by means of Monte Carlo models. ENAs that collide in the upper atmosphere deposit their energy and heat the surrounding atmosphere mainly above the main XUV energy deposition layer. It is shown that precipitating ENAs modify the thermal structure of the upper atmosphere, but the enhancement of the thermal escape rates caused by these energetic hydrogen atoms is negligible. Our results also indicate that the majority of oxygen arising from dissociated H2O molecules is left behind during the first 100 Myr. It is thus suggested that the main part of the remaining oxygen has been absorbed by crustal oxidation.

  15. Integrating Solar Power onto the Electric Grid - Bridging the Gap between Atmospheric Science, Engineering and Economics

    NASA Astrophysics Data System (ADS)

    Ghonima, M. S.; Yang, H.; Zhong, X.; Ozge, B.; Sahu, D. K.; Kim, C. K.; Babacan, O.; Hanna, R.; Kurtz, B.; Mejia, F. A.; Nguyen, A.; Urquhart, B.; Chow, C. W.; Mathiesen, P.; Bosch, J.; Wang, G.

    2015-12-01

    One of the main obstacles to high penetrations of solar power is the variable nature of solar power generation. To mitigate variability, grid operators have to schedule additional reliability resources, at considerable expense, to ensure that load requirements are met by generation. Thus despite the cost of solar PV decreasing, the cost of integrating solar power will increase as penetration of solar resources onto the electric grid increases. There are three principal tools currently available to mitigate variability impacts: (i) flexible generation, (ii) storage, either virtual (demand response) or physical devices and (iii) solar forecasting. Storage devices are a powerful tool capable of ensuring smooth power output from renewable resources. However, the high cost of storage is prohibitive and markets are still being designed to leverage their full potential and mitigate their limitation (e.g. empty storage). Solar forecasting provides valuable information on the daily net load profile and upcoming ramps (increasing or decreasing solar power output) thereby providing the grid advance warning to schedule ancillary generation more accurately, or curtail solar power output. In order to develop solar forecasting as a tool that can be utilized by the grid operators we identified two focus areas: (i) develop solar forecast technology and improve solar forecast accuracy and (ii) develop forecasts that can be incorporated within existing grid planning and operation infrastructure. The first issue required atmospheric science and engineering research, while the second required detailed knowledge of energy markets, and power engineering. Motivated by this background we will emphasize area (i) in this talk and provide an overview of recent advancements in solar forecasting especially in two areas: (a) Numerical modeling tools for coastal stratocumulus to improve scheduling in the day-ahead California energy market. (b) Development of a sky imager to provide short term

  16. Accessing Solar Irradiance Data via LISIRD, the Laboratory for Atmospheric and Space Physics Interactive Solar Irradiance Datacenter

    NASA Astrophysics Data System (ADS)

    Pankratz, C. K.; Wilson, A.; Snow, M. A.; Lindholm, D. M.; Woods, T. N.; Traver, T.; Woodraska, D.

    2015-12-01

    The LASP Interactive Solar Irradiance Datacenter, LISIRD, http://lasp.colorado.edu/lisird, allows the science community and the public to explore and access solar irradiance and related data sets using convenient, interactive or scriptable, standards-based interfaces. LISIRD's interactive plotting allows users to investigate and download irradiance data sets from a variety of sources, including space missions, ground observatories, and modeling efforts. LISIRD's programmatic interfaces allow software-level data retrievals and facilitate automation. This presentation will describe the current state of LISIRD, provide details of the data sets it serves, outline data access methods, identify key technologies in-use, and address other related aspects of serving spectral and other time series data. We continue to improve LISIRD by integrating new data sets, and also by advancing its data management and presentation capabilities to meet evolving best practices and community needs. LISIRD is hosted and operated by the Laboratory for Atmospheric and Space Physics, LASP, which has been a leader in Atmospheric and Heliophysics science for over 60 years. LASP makes a variety of space-based measurements of solar irradiance, which provide crucial input for research and modeling in solar-terrestrial interactions, space physics, planetary, atmospheric, and climate sciences. These data sets consist of fundamental measurements, composite data sets, solar indices, space weather products, and models. Current data sets available through LISIRD originate from the SORCE, SDO (EVE), UARS (SOLSTICE), TIMED (SEE), and SME space missions, as well as several other space and ground-based projects. LISIRD leverages several technologies to provide flexible and standards-based access to the data holdings available through LISIRD. This includes internet-accessible interfaces that permit data access in a variety of formats, data subsetting, as well as program-level access from data analysis

  17. Radar wind profiler observations of solar semidiurnal atmospheric tides

    SciTech Connect

    Whiteman, C.D.; Bian, X.

    1995-04-15

    Semidiurnal solar tides in the mid-latitude troposhphere are investigated using harmonic analysis of 404 MHz radar profiler wind data obtained from a wide longitude zone in the U.S. The tides are apparent above a 1000-m-deep surface layer and increase in amplitude with height, attaining speeds of 0.5-0.7 m/s at 5-7 km. Observed wind characteristics agree well with tidal characteristics obtained with a dynamical model driven by observed global semidiurnal horizontal pressure gradients. 10 refs., 6 figs., 1 tab.

  18. Ultrafast High Accuracy PCRTM_SOLAR Model for Cloudy Atmosphere

    NASA Technical Reports Server (NTRS)

    Yang, Qiguang; Liu, Xu; Wu, Wan; Yang, Ping; Wang, Chenxi

    2015-01-01

    An ultrafast high accuracy PCRTM_SOLAR model is developed based on PCA compression and principal component-based radiative transfer model (PCRTM). A fast algorithm for simulation of multi-scattering properties of cloud and/or aerosols is integrated into the fast infrared PCRTM. We completed radiance simulation and training for instruments, such as IASI, AIRS, CrIS, NASTI and SHIS, under diverse conditions. The new model is 5 orders faster than 52-stream DISORT with very high accuracy for cloudy sky radiative transfer simulation. It is suitable for hyperspectral remote data assimilation and cloudy sky retrievals.

  19. Influence of solar magnetic sector structure on terrestrial atmosphere vorticity

    NASA Technical Reports Server (NTRS)

    Wilcox, J. M.; Scherrer, P. H.; Svalgaard, L.; Roberts, W. O.; Olson, R. H.; Jenne, R. L.

    1973-01-01

    The solar magnetic sector structure has a sizable and reproducible influence on tropospheric and lower stratospheric vorticity. The average vorticity during winter in the Northhern Hemisphere north of 20 deg N latitude reaches a minimum approximately one day after the passing of a sector boundary, and then increases during the following two or three days. The effect is found at all heights within the troposphere, but is not prominent in the stratosphere, except at the lower levels. No single longitudinal interval appears to dominate the effect.

  20. The solar atmosphere and the structure of active regions

    NASA Technical Reports Server (NTRS)

    Sturrock, P. A.

    1974-01-01

    The existence of 'holes' in the corona is reported characterized by abnormally low densities and temperatures. It was found that such coronal holes appear to be the source of high-velocity, enhanced-density streams in the solar wind as observed at the earth's orbit. It was further noted that coronal holes appear to be associated with regions of diverging magnetic fields in the corona. Models were developed to accomplish the objective for the principal energy flows in the transition region and corona.

  1. Magnetohydrostatic Equilibrium. II. Three-dimensional Multiple Open Magnetic Flux Tubes in the Stratified Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Gent, F. A.; Fedun, V.; Erdélyi, R.

    2014-07-01

    A system of multiple open magnetic flux tubes spanning the solar photosphere and lower corona is modeled analytically, within a realistic stratified atmosphere subject to solar gravity. This extends results for a single magnetic flux tube in magnetohydrostatic equilibrium, described in Gent et al. Self-similar magnetic flux tubes are combined to form magnetic structures, which are consistent with high-resolution observations. The observational evidence supports the existence of strands of open flux tubes and loops persisting in a relatively steady state. Self-similar magnetic flux tubes, for which an analytic solution to the plasma density and pressure distribution is possible, are combined. We calculate the appropriate balancing forces, applying to the equations of momentum and energy conservation to preserve equilibrium. Multiplex flux tube configurations are observed to remain relatively stable for up to a day or more, and it is our aim to apply our model as the background condition for numerical studies of energy transport mechanisms from the solar surface to the corona. We apply magnetic field strength, plasma density, pressure, and temperature distributions consistent with observational and theoretical estimates for the lower solar atmosphere. Although each flux tube is identical in construction apart from the location of the radial axis, combinations can be applied to generate a non-axisymmetric magnetic field with multiple non-uniform flux tubes. This is a considerable step forward in modeling the realistic magnetized three-dimensional equilibria of the solar atmosphere.

  2. Magnetohydrostatic equilibrium. II. Three-dimensional multiple open magnetic flux tubes in the stratified solar atmosphere

    SciTech Connect

    Gent, F. A.; Erdélyi, R.; Fedun, V.

    2014-07-01

    A system of multiple open magnetic flux tubes spanning the solar photosphere and lower corona is modeled analytically, within a realistic stratified atmosphere subject to solar gravity. This extends results for a single magnetic flux tube in magnetohydrostatic equilibrium, described in Gent et al. Self-similar magnetic flux tubes are combined to form magnetic structures, which are consistent with high-resolution observations. The observational evidence supports the existence of strands of open flux tubes and loops persisting in a relatively steady state. Self-similar magnetic flux tubes, for which an analytic solution to the plasma density and pressure distribution is possible, are combined. We calculate the appropriate balancing forces, applying to the equations of momentum and energy conservation to preserve equilibrium. Multiplex flux tube configurations are observed to remain relatively stable for up to a day or more, and it is our aim to apply our model as the background condition for numerical studies of energy transport mechanisms from the solar surface to the corona. We apply magnetic field strength, plasma density, pressure, and temperature distributions consistent with observational and theoretical estimates for the lower solar atmosphere. Although each flux tube is identical in construction apart from the location of the radial axis, combinations can be applied to generate a non-axisymmetric magnetic field with multiple non-uniform flux tubes. This is a considerable step forward in modeling the realistic magnetized three-dimensional equilibria of the solar atmosphere.

  3. Solar Resource & Meteorological Assessment Project (SOLRMAP): Observed Atmospheric and Solar Information System (OASIS); Tucson, Arizona (Data)

    DOE Data Explorer

    Wilcox, S.; Andreas, A.

    2010-11-03

    The U.S. Department of Energy's National Renewable Energy Laboratory collaborates with the solar industry to establish high quality solar and meteorological measurements. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar power projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.

  4. The role of gravity waves in solar-terrestrial atmosphere coupling and severe storm detection

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    The role that gravity waves play in the coupling of the solar wind and the ionosphere, the coupling of high and low latitude ionospheres, and the coupling of the ionosphere and the neutral atmosphere are discussed. Examples are given of the detection of tornado touchdowns from locating the sources of the gravity waves.

  5. Modification of solar radiation components under different atmospheric conditions in the Greater Athens Area, Greece

    NASA Astrophysics Data System (ADS)

    Kaskaoutis, D. G.; Kambezidis, H. D.; Jacovides, C. P.; Steven, M. D.

    2006-06-01

    The influence of the atmospheric turbidity on the spectral distribution of solar irradiance components is investigated using ground-based spectroradiometric measurements taken in Athens area during May 1995. It is found that both the diffuse-to-global and diffuse-to-direct-beam irradiance ratios exhibits a strong wavelength dependence and exponential curves associated with 99% of the variance can fit each parameter. These exponential curves are further modified as function of the solar zenith angle and atmospheric turbidity conditions. It is found that the slope of the curves strongly depends on the processes attenuating irradiance and aerosol optical characteristics in the short wavelengths. New relations are proposed, which allow the spectral distribution of diffuse irradiance to be estimated as a function of the measured broadband global and diffuse solar irradiances. The diffuse-to-direct-beam ratio, which is an indicator of the atmospheric transmittance, exhibits a strong wavelength and aerosol-loading dependence. The observed differences between turbid urban and clean rural atmospheres constitute a manifestation of contrasting air properties and influence solar irradiance spectra.

  6. Solar radiation budgets in atmospheric model intercomparisons from a surface perspective

    NASA Astrophysics Data System (ADS)

    Wild, Martin

    2005-04-01

    Solar radiation budgets from 20 general circulation models (GCMs) participating in the second phase of the Atmospheric Model Intercomparison Project (AMIPII) are analyzed. The models largely differ in their global mean radiation budgets, particularly at the surface. Compared to a comprehensive data set of 760 worldwide-distributed surface stations from the Global Energy Balance Archive, the models tend to overestimate the land surface insolation by 9 Wm-2 on average. The biases in the net solar fluxes at the top of atmosphere are generally smaller. This suggests that the excessive surface insolation in the GCMs is rather related to inaccurate partitioning of solar absorption between surface and atmosphere than to excessive absorption by the planet as a whole. This applies also to 13 state-of-the-art GCMs participating in IPCC AR4. Uncertainties in the solar absorption by the atmospheric constituents are thus still significant in current GCMs and contribute to the large discrepancies amongst the GCM radiation budgets and their biases compared to surface observations.

  7. The role of gravity waves in solar-terrestrial atmosphere coupling and severe storm detection

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    The role that gravity waves play in the coupling of the solar wind and the ionosphere, the coupling of high and low latitude ionospheres, and the coupling of the ionosphere and the neutral atmosphere are discussed. Examples are given of the detection of tornado touchdowns from locating the sources of the gravity waves.

  8. Waves & Oscillations in the Solar Atmosphere: Heating and Magneto-Seismology

    NASA Astrophysics Data System (ADS)

    Erdélyi, Robert; Mendoza-Briceno, César A.

    2008-06-01

    Preface; Organizing committee; Conference participants; Address by the Scientific Organizing Committee R. Erdélyi; Progress in coronal seismology B. Roberts; Session 1. Waves and oscillations in solar and stellar interior Robert Erdélyi; Session 2. Coupling of global solar and stellar motions into the lower atmosphere Bernard Roberts; Session 3. Seismology of the lower solar atmosphere and stellar chromospheres Siraj S. Hasan; Session 4. Seismology of open versus closed magnetic structures Marcel Goossens; Session 5. Prominence seismology Jose Luis Ballester; Session 6. Dynamical processes and coupling in the magnetic atmosphere of Sun and stars Miguel Ibañez; Session 7. Wave-particle interactions in magnetized plasmas Cesar A. Mendoza-Briceño; Session 8. Solar and stellar global coronal seismology Viggo Hansteen; Session 9. Fundamental physical processes in coronae: waves, turbulence, reconnection Saku Tsuneta; Session 10. Waves and instabilities in atmospheric plasmas Arnold O. Benz; Summary of meeting Cesar A. Mendoza-Briceño; Concluding remarks A. O. Benz; Late papers; Author index.

  9. An investigation of solar wind effects on the evolution of the Martian atmosphere

    NASA Technical Reports Server (NTRS)

    Luhmann, Janet G.

    1994-01-01

    This investigation concentrated on the question of how atmosphere escape, related to both photochemistry and the Mars solar wind interaction, may have affected the evolution of Mars' atmosphere over time. The principal investigator and postdoctoral researcher adopted the premise that contemporary escape processes have dominated the losses to space over the past 3.5 billion years, but that the associated loss rates have been modified by solar evolution. A model was constructed for the contemporary escape scenario based on knowledge gained from both Venus in-situ measurements from Pioneer Venus Orbiter and Mars measurements from Phobos-2. Venus provided a valuable second example of a weakly magnetized planet having a similar solar wind interaction where we have more knowledge from observations. The model included photochemical losses from recombining ionospheric molecular ions, scavenging Martian upper atmosphere ('pickup') ions by the solar wind, and sputtering of the atmosphere by reentering pickup ions. The existence of the latter mechanism was realized during the course of the supported investigation, and is now thought by Jakosky and Pepin to explain some of the Martian noble gas isotope ratios.

  10. The Long-term Middle Atmospheric Influence of Very Large Solar Proton Events

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Marsh, Daniel R.; Vitt, Francis M.; Garcia, Rolando R.; Randall, Cora E.; Fleming, Eric L.; Frith, Stacey M.

    2008-01-01

    Long-term variations in ozone have been caused by both natural and humankind related processes. The humankind or anthropogenic influence on ozone originates from the chlorofluorocarbons and halons (chlorine and bromine) and has led to international regulations greatly limiting the release of these substances. Certain natural ozone influences are also important in polar regions and are caused by the impact of solar charged particles on the atmosphere. Such natural variations have been studied in order to better quantify the human influence on polar ozone. Large-scale explosions on the Sun near solar maximum lead to emissions of charged particles (mainly protons and electrons), some of which enter the Earth's magnetosphere and rain down on the polar regions. "Solar proton events" have been used to describe these phenomena since the protons associated with these solar events sometimes create a significant atmospheric disturbance. We have used the National Center for Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM) to study the long-term (> few months) influences of solar proton events from 1963 through 2004 on stratospheric ozone and temperature. There were extremely large solar proton events in 1972, 1989,2000,2001, and 2003. These events caused very distinctive polar changes in layers of the Earth's atmosphere known as the stratosphere (12-50 km; -7-30 miles) and mesosphere (50-90 km; 30-55 miles). The solar protons connected with these events created hydrogen- and nitrogen-containing compounds, which led to the polar ozone destruction. The nitrogen-containing compounds, called odd nitrogen, lasted much longer than the hydrogen-containing compounds and led to long-lived stratospheric impacts. An extremely active period for these events occurred in the five-year period, 2000- 2004, and caused increases in odd nitrogen which lasted for several months after individual events. Associated stratospheric ozone decreases of >lo% were calculated

  11. Response of the AMOC to reduced solar radiation - the modulating role of atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    Muthers, Stefan; Raible, Christoph C.; Rozanov, Eugene; Stocker, Thomas F.

    2016-11-01

    The influence of reduced solar forcing (grand solar minimum or geoengineering scenarios like solar radiation management) on the Atlantic Meridional Overturning Circulation (AMOC) is assessed in an ensemble of atmosphere-ocean-chemistry-climate model simulations. Ensemble sensitivity simulations are performed with and without interactive chemistry. In both experiments the AMOC is intensified in the course of the solar radiation reduction, which is attributed to the thermal effect of the solar forcing: reduced sea surface temperatures and enhanced sea ice formation increase the density of the upper ocean in the North Atlantic and intensify the deepwater formation. Furthermore, a second, dynamical effect on the AMOC is identified driven by the stratospheric cooling in response to the reduced solar forcing. The cooling is strongest in the tropics and leads to a weakening of the northern polar vortex. By stratosphere-troposphere interactions, the stratospheric circulation anomalies induce a negative phase of the Arctic Oscillation in the troposphere which is found to weaken the AMOC through wind stress and heat flux anomalies in the North Atlantic. The dynamic mechanism is present in both ensemble experiments. In the experiment with interactive chemistry, however, it is strongly amplified by stratospheric ozone changes. In the coupled system, both effects counteract and weaken the response of the AMOC to the solar forcing reduction. Neglecting chemistry-climate interactions in model simulations may therefore lead to an overestimation of the AMOC response to solar forcing.

  12. Helioseismology: A probe of the solar interior, atmosphere, and activity cycle

    NASA Technical Reports Server (NTRS)

    Rhodes, E. J., Jr.

    1995-01-01

    Helioseismology began in earnest in the mid 1970's. In the two decades which have elapsed since that time this branch of solar physics has become a mature field of research. Helioseismology has demonstrated that the solar convection zone is about twice as deep as was generally thought to be the case before 1977. Helioseismology has also provided measurements of the solar internal angular velocity over much of the sun's interior. Helioseismology has also ruled out models which would solve the solar neutrino problem by a lowering of the temperature of the core. Recently, some of the seismic properties of the sun have been demonstrated to vary with changing levels of solar activity. Also, helioseismology has recently provided evidence for helical flow patterns in the shallow, sub-photosphere layers. The techniques of helioseismology are also expanding to include seismic probes of solar active regions. Some work is also being conducted into the possible contributions of the solar acoustic models to the heating of the solar atmosphere. In this talk I will highlight a few of the above results and concentrate on current areas of research in the field.

  13. HOW MUCH DOES A MAGNETIC FLUX TUBE EMERGE INTO THE SOLAR ATMOSPHERE?

    SciTech Connect

    Magara, T.

    2012-03-20

    The emergence process of the magnetic field into the solar atmosphere plays an essential role in determining the configuration of the magnetic field and its activity on the Sun. This paper focuses on how much the magnetic flux contained by a flux tube emerges into the solar atmosphere, which is the key to understanding the physical mechanism of solar eruptions. By comparing a kinematic model of an emerging flux tube to a series of magnetohydrodynamic simulations, we derive the characteristics of the emergence process, showing how the process depends on the pre-emerged state of the magnetic field such as the radius of a flux tube, field strength, field-line twist, and wavelength of undulation assumed by the flux tube. We also discuss the relationship between magnetic configurations and their stability on the Sun.

  14. Newtonian CAFE: a new ideal MHD code to study the solar atmosphere

    NASA Astrophysics Data System (ADS)

    González, J. J.; Guzmán, F.

    2015-12-01

    In this work we present a new independent code designed to solve the equations of classical ideal magnetohydrodynamics (MHD) in three dimensions, submitted to a constant gravitational field. The purpose of the code centers on the analysis of solar phenomena within the photosphere-corona region. In special the code is capable to simulate the propagation of impulsively generated linear and non-linear MHD waves in the non-isothermal solar atmosphere. We present 1D and 2D standard tests to demonstrate the quality of the numerical results obtained with our code. As 3D tests we present the propagation of MHD-gravity waves and vortices in the solar atmosphere. The code is based on high-resolution shock-capturing methods, uses the HLLE flux formula combined with Minmod, MC and WENO5 reconstructors. The divergence free magnetic field constraint is controlled using the Flux Constrained Transport method.

  15. Atmospheric Ionization by Solar Particles Detected by Nitrate Measurements in Antarctic Snow. FY91 AASERT

    NASA Technical Reports Server (NTRS)

    Vitt, Francis M.; Jackman, Charles H.

    1995-01-01

    The odd nitrogen source strengths associated with Solar Proton Events (SPEs), Galactic Cosmic Rays (GCRs), and the oxidation of nitrous oxide in the Earth's middle atmosphere from 1974 through 1993 have been compared globally, at middle and lower latitudes (less than 50 deg), and polar regions (greater than 50 deg) with a two-dimensional (2-D) photochemical transport model. As discovered previously, the oxidation of nitrous oxide dominates the global odd nitrogen source while GCRs and SPEs are significant at polar latitudes. The horizontal transport of odd nitrogen, produced by the oxidation of nitrous oxide at latitudes < 50 deg, was found to be the dominant source of odd nitrogen in the polar regions with GCRs contributing substantially during the entire solar cycle. The source of odd nitrogen from SPEs was more sporadic; however, contributions during several years (mostly near solar maximum) were significant in the polar middle atmosphere.

  16. Sensitivity of solar-cell performance to atmospheric variables. 1: Single cell

    NASA Technical Reports Server (NTRS)

    Klucher, T. M.

    1976-01-01

    The short circuit current of a typical silicon solar cell under direct solar radiation was measured for a range of turbidity, water vapor content, and air mass to determine the relation of the solar cell calibration value (current-to-intensity ratio) to those atmospheric variables. A previously developed regression equation was modified to describe the relation between calibration value, turbidity, water vapor content, and air mass. Based on the value of the constants obtained by a least squares fit of the data to the equation, it was found that turbidity lowers the value, while increase in water vapor increases the calibration value. Cell calibration values exhibited a change of about 6% over the range of atmospheric conditions experienced.

  17. LOW-FREQUENCY RADIO OBSERVATIONS OF PICOFLARE CATEGORY ENERGY RELEASES IN THE SOLAR ATMOSPHERE

    SciTech Connect

    Ramesh, R.; Sasikumar Raja, K.; Kathiravan, C.; Satya Narayanan, A.

    2013-01-10

    We report low-frequency (80 MHz) radio observations of circularly polarized non-thermal type I radio bursts ({sup n}oise storms{sup )} in the solar corona whose estimated energy is {approx}10{sup 21} erg. These are the weakest energy release events reported to date in the solar atmosphere. The plot of the distribution of the number of bursts (dN) versus their corresponding peak flux density in the range S to S+dS shows a power-law behavior, i.e., dN {proportional_to} S {sup {gamma}} dS. The power-law index {gamma} is in the range -2.2 to -2.7 for the events reported in the present work. The present results provide independent observational evidence for the existence of picoflare category energy releases in the solar atmosphere which are yet to be explored.

  18. Polarized Radiation Diagnostics for Measuring the Magnetic Field of the Outer Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Trujillo Bueno, J.

    2012-12-01

    The basic idea of optical pumping, for which Alfred Kastler received the 1966 Nobel Prize in physics, is that the absorption and scattering of light that is near-resonant with an optical transition can produce large population imbalances among the magnetic sublevels of atomic ground states as well as in excited states. The degree of this radiatively-induced atomic level polarization, which is very sensitive to the presence of magnetic fields, can be determined by observing the polarization of the scattered or transmitted spectral line radiation. Probably, the most important point for solar physics is that the outer solar atmosphere is indeed an optically pumped vapor and that the polarization of the emergent spectral line radiation can be exploited for detecting magnetic fields that are too weak and/or too tangled so as to produce measurable Zeeman polarization signals. In this talk we review some recent radiative transfer simulations of the polarization produced by optical pumping in selected IR, FUV and EUV spectral lines, showing that their sensitivity to the Hanle effect is very suitable for magnetic field measurements in the outer solar atmosphere. We argue that solar magnetometry using the spectral lines of optically pumped atoms in the chromosphere, transition region and corona should be a high-priority goal for large aperture solar telescopes, such as ATST, EST and SOLAR-C.

  19. Limitation of Ground-based Estimates of Solar Irradiance Due to Atmospheric Variations

    NASA Technical Reports Server (NTRS)

    Wen, Guoyong; Cahalan, Robert F.; Holben, Brent N.

    2003-01-01

    The uncertainty in ground-based estimates of solar irradiance is quantitatively related to the temporal variability of the atmosphere's optical thickness. The upper and lower bounds of the accuracy of estimates using the Langley Plot technique are proportional to the standard deviation of aerosol optical thickness (approx. +/- 13 sigma(delta tau)). The estimates of spectral solar irradiance (SSI) in two Cimel sun photometer channels from the Mauna Loa site of AERONET are compared with satellite observations from SOLSTICE (Solar Stellar Irradiance Comparison Experiment) on UARS (Upper Atmospheric Research Satellite) for almost two years of data. The true solar variations related to the 27-day solar rotation cycle observed from SOLSTICE are about 0.15% at the two sun photometer channels. The variability in ground-based estimates is statistically one order of magnitude larger. Even though about 30% of these estimates from all Level 2.0 Cimel data fall within the 0.4 to approx. 0.5% variation level, ground-based estimates are not able to capture the 27-day solar variation observed from SOLSTICE.

  20. Chromospheric anemone jets and magnetic reconnection in partially ionized solar atmosphere

    SciTech Connect

    Singh, K. A. P.; Shibata, K.; Nishizuka, N.; Isobe, H.

    2011-11-15

    The solar optical telescope onboard Hinode with temporal resolution of less than 5 s and spatial resolution of 150 km has observed the lower solar atmosphere with an unprecedented detail. This has led to many important findings, one of them is the discovery of chromospheric anemone jets in the solar chromosphere. The chromospheric anemone jets are ubiquitous in solar chromosphere and statistical studies show that the typical length, life time and energy of the chromospheric anemone jets are much smaller than the coronal events (e.g., jets/flares/CMEs). Among various observational parameters, the apparent length and maximum velocity shows good correlation. The velocity of chromospheric anemone jets is comparable to the local Alfven speed in the lower solar chromosphere. Since the discovery of chromospheric anemone jets by Hinode, several evidences of magnetic reconnection in chromospheric anemone jets have been found and these observations are summarized in this paper. These observations clearly suggest that reconnection occurs quite rapidly as well as intermittently in the solar chromosphere. In the solar corona ({lambda}{sub i} > {delta}{sub SP}), anomalous resistivity arises due to various collisionless processes. Previous MHD simulations show that reconnection becomes fast as well as strongly time-dependent due to anomalous resistivity. Such processes would not arise in the solar chromosphere which is fully collisional and partially-ionized. So, it is unclear how the rapid and strongly time-dependent reconnection would occur in the solar chromosphere. It is quite likely that the Hall and ambipolar diffusion are present in the solar chromosphere and they could play an important role in driving such rapid, strongly time-dependent reconnection in the solar chromosphere.

  1. Chromospheric anemone jets and magnetic reconnection in partially ionized solar atmosphere

    NASA Astrophysics Data System (ADS)

    Singh, K. A. P.; Shibata, K.; Nishizuka, N.; Isobe, H.

    2011-11-01

    The solar optical telescope onboard Hinode with temporal resolution of less than 5 s and spatial resolution of 150 km has observed the lower solar atmosphere with an unprecedented detail. This has led to many important findings, one of them is the discovery of chromospheric anemone jets in the solar chromosphere. The chromospheric anemone jets are ubiquitous in solar chromosphere and statistical studies show that the typical length, life time and energy of the chromospheric anemone jets are much smaller than the coronal events (e.g., jets/flares/CMEs). Among various observational parameters, the apparent length and maximum velocity shows good correlation. The velocity of chromospheric anemone jets is comparable to the local Alfvén speed in the lower solar chromosphere. Since the discovery of chromospheric anemone jets by Hinode, several evidences of magnetic reconnection in chromospheric anemone jets have been found and these observations are summarized in this paper. These observations clearly suggest that reconnection occurs quite rapidly as well as intermittently in the solar chromosphere. In the solar corona (λi > δSP), anomalous resistivity arises due to various collisionless processes. Previous MHD simulations show that reconnection becomes fast as well as strongly time-dependent due to anomalous resistivity. Such processes would not arise in the solar chromosphere which is fully collisional and partially-ionized. So, it is unclear how the rapid and strongly time-dependent reconnection would occur in the solar chromosphere. It is quite likely that the Hall and ambipolar diffusion are present in the solar chromosphere and they could play an important role in driving such rapid, strongly time-dependent reconnection in the solar chromosphere.

  2. Stochastic Transients as a Source of Quasi-periodic Processes in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Yuan, Ding; Su, Jiangtao; Jiao, Fangran; Walsh, Robert W.

    2016-06-01

    Solar dynamics and turbulence occur at all heights of the solar atmosphere and could be described as stochastic processes. We propose that finite-lifetime transients recurring at a certain place could trigger quasi-periodic processes in the associated structures. In this study, we developed a mathematical model for finite-lifetime and randomly occurring transients, and found that quasi-periodic processes with periods longer than the timescale of the transients, are detectable intrinsically in the form of trains. We simulate their propagation in an empirical solar atmospheric model with chromosphere, transition region, and corona. We found that, due to the filtering effect of the chromospheric cavity, only the resonance period of the acoustic resonator is able to propagate to the upper atmosphere; such a scenario is applicable to slow magnetoacoustic waves in sunspots and active regions. If the thermal structure of the atmosphere is less wild and acoustic resonance does not take place, the long-period oscillations could propagate to the upper atmosphere. Such a case would be more likely to occur in polar plumes.

  3. Impact of cosmic rays and solar energetic particles on the Earth's ionosphere and atmosphere

    NASA Astrophysics Data System (ADS)

    Velinov, Peter I. Y.; Asenovski, Simeon; Kudela, Karel; Lastovicka, Jan; Mateev, Lachezar; Mishev, Alexander; Tonev, Peter

    2013-03-01

    A brief review of the study during COST Action ES0803 of effects due to cosmic rays (CR) and solar energetic particles (SEP) in the ionosphere and atmosphere is presented. Models CORIMIA (COsmic Ray Ionization Model for Ionosphere and Atmosphere) and application of CORSIKA (COsmic Ray SImulations for KAscade) code are considered. They are capable to compute the cosmic ray ionization profiles at a given location, time, solar and geomagnetic activity. Intercomparison of the models, as well as comparison with direct measurements of the atmospheric ionization, validates their applicability for the entire atmosphere and for the different levels of the solar activity. The effects of CR and SEP can be very strong locally in the polar cap regions, affecting the physical-chemical and electrical properties of the ionosphere and atmosphere. Contributions here were also made by the anomalous CR, whose ionization is significant at high geomagnetic latitudes (above 65°-70°). Several recent achievements and application of CR ionization models are briefly presented. This work is the output from the SG 1.1 of the COST ES0803 action (2008-2012) and the emphasis is given on the progress achieved by European scientists involved in this collaboration.

  4. Mars atmosphere loss and isotopic fractionation by solar-wind-induced sputtering and photochemical escape

    NASA Technical Reports Server (NTRS)

    Jakosky, B. M.; Pepin, R. O.; Johnson, R. E.; Fox, J. L.

    1993-01-01

    The effects of loss of Mars atmospheric constituents by solar-wind-induced sputtering and by photochemical escape during the last 3.8 b.y. were examined. Sputtering is capable of efficiently removing all species from the upper atmosphere, including the light noble gases; N also is removed by photochemical processes. Due to the diffusive separation by mass above the homopause, removal from the top of the atmosphere will fractionate the isotopes of each species, with the lighter mass being preferentially lost. For C and O, this allows us to determine the size of nonatmospheric reservoirs that mix with the atmosphere; these reserviors can be accounted for by exchange with CO2 adsorbed in the regolith and with H2O in the polar ice deposits. Both simple analytical models and time-dependent models of the loss of volatiles from and supply to the Martian atmosphere were constructed. Both Ar and Ne require continued replenishment from outgassing over geologic time.

  5. Mars atmospheric loss and isotopic fractionation by solar-wind-induced sputtering and photochemical escape

    NASA Technical Reports Server (NTRS)

    Jakosky, B. M.; Pepin, R. O.; Johnson, R. E.; Fox, J. L.

    1993-01-01

    We examine the effects of loss of Mars atmospheric constituents by solar-wind-induced sputtering and by photochemical escape during the last 3.8 b.y. Sputtering is capable of efficiently removing all species from the upper atmosphere including the light noble gases; N is removed by photochemical processes as well. Due to diffusive separation (by mass) above the homopause, removal from the top of the atmosphere will fractionate the isotopes of each species with the lighter mass being preferentially lost. For C and O, this allows us to determine the size of nonatmospheric reservoirs that mix with the atmosphere; these reservoirs can be CO2 adsorbed in the regolith or H2O in the polar ice caps. We have constructed both simple analytical models and time-dependent models of the loss from and supply of volatiles to the Martian atmosphere.

  6. Effects of Chemical Abundances on the Structure and Dynamics of the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Demarque, Pierre; Basu, S.; Robinson, F.; Hunter, C.; Kallinger, T.

    2008-05-01

    This paper presents a comparison between two three-dimensional radiative hydrodynamical (3D RHD) simulations of the solar outer layers using the Grevesse & Sauval (1998; GS98) and the Asplund, Grevesse & Sauval (2005; AGS05) mixtures, respectively. The AGS05 mixture is a revision of the solar abundance mixture using a model atmosphere based on the stratification and dynamics of a solar 3D RHD simulation performed with the GS98 mixture, using the code of Stein & Nordlund (1989, 1998). Our simulations use the same code, and physically realistic treatment of radiative opacities and equation of state as Robinson et al. (2003). A comparison between our GS98 and AGS05 3D simulations shows differences both in the mean vertical temperature gradient and in the turbulent velocity field in the line forming region of the solar atmosphere. The whole superadiabatic layer (SAL) in the AGS05 simulation, including its peak, is shifted outward with respect to the GS98 SAL. Turbulent velocities, critical for absorption line profile calculations, are larger in the AGS05 simulation by about 10%. Since opacities for the AGS05 mixture are lower than those for the GS98 mixture, the T-τ relations derived from the two simulations are different. At 5000K, τ obtained from the GS98 simulation is about 30% larger than that obtained from the AGS05 simulation. These results show the importance of preserving self consistency in the chemical abundances between the model atmosphere and the 3D HRD simulation. When deriving the solar abundances, one must iterate the chemical composition in the model atmosphere, and hence in the 3D simulation on which the atmosphere is based. This research was supported in part by NASA/ATP grant NAG5-13299 (PD and FR) and NSF grant ATM 0348837 to SB.

  7. Tectonic implications of radiogenic noble gases in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Turcotte, D. L.; Schubert, G.

    1988-01-01

    An account is given of the ways in which the He-4 and Ar-40 radiogenic isotopes furnish important constraints on planetary interior tectonics. In the case of the earth, where there are such independent constraints on radiogenic isotope concentrations as observed surface heat flow, the specification of radiogenic isotope concentration allows the interpretation of data on the Ar-40 atmospheric mass and mantle He-4 in terms of models for the entire mantle and of layered mantle convection. He loss rate estimates through the Venus atmosphere indicate a flux that is nearly equal to that through the earth atmosphere.

  8. Solar modulation of atmospheric electrification through variation of the conductivity over thunderstorms

    NASA Technical Reports Server (NTRS)

    Markson, R.

    1974-01-01

    Variations of the current in the global atmospheric electrical circuit can be produced through regulation of the resistance between the tops of thunderclouds and the ionosphere. Long-and short-term changes in the conductivity of this region occur due to changes in the ionization rate resulting from solar activity. Previous suggestions that the phenomena might be due to conductivity variations in the fair weather part of the world or an influx of space charge to the upper atmosphere are considered unlikely. It might be possible to test the proposed mechanism by measuring the temporal variation of the ionospheric potential during disturbed solar periods. Another approach would be to measure simultaneously the variation in ionization rate and electric current over thunder-storms. Several ways in which changes in atmospheric electrification might influence other meteorological phenomena are mentioned.

  9. Solar modulation of atmospheric electrification through variation of the conductivity over thunderstorms

    NASA Technical Reports Server (NTRS)

    Markson, R.

    1975-01-01

    It is suggested that variations of the current in the global atmospheric electrical circuit can be produced through regulation of the resistance between the tops of thunderclouds and the ionosphere. Long- and short-term changes in the conductivity of this region occur due to changes in the ionization rate resulting from solar activity. Previous suggestions that the phenomena might be due to conductivity variations in the fair weather part of the world or an influx of space charge to the upper atmosphere are discussed and considered unlikely. It might be possible to test the proposed mechanism by measuring the temporal variation of the ionospheric potential during distributed solar periods. Another approach would be to measure simultaneously the variation in ionization rate and electric current over thunderstorms. Several ways in which changes in atmospheric electrification might influence other meteorological phenomena are mentioned.

  10. Global biomass burning - Atmospheric, climatic and biospheric implications

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.

    1990-01-01

    Changes in the trace gas composition of the atmosphere due to global biomass burning are examined. The environmental consequences of those changes which have become areas of international concern are discussed.

  11. Recent advances in satellite observations of solar variability and global atmospheric ozone

    NASA Technical Reports Server (NTRS)

    Heath, D. F.

    1974-01-01

    A description is given of the temporal behavior of the sun as an ultraviolet variable star in relation to daily zonal means of atmospheric ozone from the total amount to that above the 10-mb and 4-mb pressure levels. A significant correlation has been observed between enhancements in the ultraviolet solar irradiances and terrestrial passages of the solar magnetic field sector boundary structure. However, it has not yet been possible to separate solar from the dynamical effects on the variability in the zonal means of ozone. Attention is given to global changes in ozone which have been derived from the satellite observations in terms of season, solar variability, and major stratospheric disturbances such as stratospheric warmings.

  12. Initial Results of Aperture Area Comparisons for Exo-Atmospheric Total Solar Irradiance Measurements

    NASA Technical Reports Server (NTRS)

    Johnson, B. Carol; Litorja, Maritoni; Fowler, Joel B.; Butler, James J.

    2009-01-01

    In the measurement of exo-atmospheric total solar irradiance (TSI), instrument aperture area is a critical component in converting solar radiant flux to irradiance. In a May 2000 calibration workshop for the Total Irradiance Monitor (TIM) on the Earth Observing System (EOS) Solar Radiation and Climate Experiment (SORCE), the solar irradiance measurement community recommended that NASA and NISI coordinate an aperture area measurement comparison to quantify and validate aperture area uncertainties and their overall effect on TSI uncertainties. From May 2003 to February 2006, apertures from 4 institutions with links to the historical TSI database were measured by NIST and the results were compared to the aperture area determined by each institution. The initial results of these comparisons are presented and preliminary assessments of the participants' uncertainties are discussed.

  13. The solar ultraviolet spectral irradiance monitor (SUSIM) experiment on board the Upper Atmosphere Research Satellite (UARS)

    NASA Technical Reports Server (NTRS)

    Brueckner, G. E.; Edlow, K. L.; Floyd, L. E., IV; Lean, J. L.; Vanhoosier, M. E.

    1993-01-01

    The state of solar ultraviolet irradiance measurements in 1978, when NASA requested proposals for a new generation of solar ultraviolet monitors to be flown on the Upper Atmosphere Research Satellite (UARS), is described. To overcome the radiometric uncertainties that plagued the measurements at this time, the solar ultraviolet spectral irradiance monitor (SUSIM) instrument design included in-flight calibration light sources and multichannel photometers. Both are aimed at achieving a maximum precision of the SUSIM measurements over a long period of time, e.g., one solar cycle. The design of the SUSIM-UARS instrument is compared with the original design specifications for the UARS instruments. Details including optical train, filters, detectors, and contamination precautions are described. Also discussed are the SUSIM-UARS preflight calibration and characterization, as well as the results of the inflight performance of the instrument during the first 3 months of operation. Finally, flight operations, observation strategy, and data reduction schemes are outlined.

  14. An extreme ultraviolet photometer for solar observations from the Atmosphere Explorer satellites

    NASA Technical Reports Server (NTRS)

    Heath, D. F.; Osantowski, J. F.

    1972-01-01

    A broadband photometer experiment is being fabricated for the Atmosphere Explorer C, D and E missions to record the solar irradiance in the 40 to 1250 A region with seven distinct passbands. The experiment consists principally of four spinal electron multipliers located behind a moving eight position filter wheel. Six metallic filters are used to spectrally isolate the solar irradiance. In addition three Al2O3 diodes, two with filters, are being used to record the solar irradiance over the range of orbital altitudes from perigee through apogee. A principal goal of the experiment will be to measure time dependence of the solar irradiance with respect to a storage ring synchrotron light source which has been calibrated in terms of the best currently available standards of irradiance.

  15. Initial Results of Aperture Area Comparisons for Exo-Atmospheric Total Solar Irradiance Measurements

    NASA Technical Reports Server (NTRS)

    Johnson, B. Carol; Litorja, Maritoni; Fowler, Joel B.; Butler, James J.

    2009-01-01

    In the measurement of exo-atmospheric total solar irradiance (TSI), instrument aperture area is a critical component in converting solar radiant flux to irradiance. In a May 2000 calibration workshop for the Total Irradiance Monitor (TIM) on the Earth Observing System (EOS) Solar Radiation and Climate Experiment (SORCE), the solar irradiance measurement community recommended that NASA and NISI coordinate an aperture area measurement comparison to quantify and validate aperture area uncertainties and their overall effect on TSI uncertainties. From May 2003 to February 2006, apertures from 4 institutions with links to the historical TSI database were measured by NIST and the results were compared to the aperture area determined by each institution. The initial results of these comparisons are presented and preliminary assessments of the participants' uncertainties are discussed.

  16. The role of ozone feedback in modulating the atmospheric response to the solar cycle forcing

    NASA Astrophysics Data System (ADS)

    Bednarz, Ewa; Maycock, Amanda; Braesicke, Peter; Telford, Paul; Abraham, Luke; Pyle, John

    2016-04-01

    in the seasonality of the dynamical response in the Northern Hemisphere high latitudes. All in all, our results highlight the importance of the solar-ozone feedback in modulating the atmospheric response to the solar cycle forcing and the importance of properly representing this for future model studies of the impact of the solar cycle forcing on climate.

  17. Is tropospheric weather influenced by solar wind through atmospheric vertical coupling downward control?

    NASA Astrophysics Data System (ADS)

    Prikryl, Paul; Tsukijihara, Takumi; Iwao, Koki; Muldrew, Donald B.; Bruntz, Robert; Rušin, Vojto; Rybanský, Milan; Turňa, Maroš; Šťastný, Pavel; Pastirčák, Vladimír

    2017-04-01

    More than four decades have passed since a link between solar wind magnetic sector boundary structure and mid-latitude upper tropospheric vorticity was discovered (Wilcox et al., Science, 180, 185-186, 1973). The link has been later confirmed and various physical mechanisms proposed but apart from controversy, little attention has been drawn to these results. To further emphasize their importance we investigate the occurrence of mid-latitude severe weather in the context of solar wind coupling to the magnetosphere-ionosphere-atmosphere (MIA) system. It is observed that significant snowstorms, windstorms and heavy rain, particularly if caused by low pressure systems in winter, tend to follow arrivals of high-speed solar wind. Previously published statistical evidence that explosive extratropical cyclones in the northern hemisphere tend to occur after arrivals of high-speed solar wind streams from coronal holes (Prikryl et al., Ann. Geophys., 27, 1-30, 2009; Prikryl et al., J. Atmos. Sol.-Terr. Phys., 149, 219-231, 2016) is corroborated for the southern hemisphere. A physical mechanism to explain these observations is proposed. The leading edge of high-speed solar wind streams is a locus of large-amplitude magneto-hydrodynamic waves that modulate Joule heating and/or Lorentz forcing of the high-latitude lower thermosphere generating medium-scale atmospheric gravity waves that propagate upward and downward through the atmosphere. Simulations of gravity wave propagation in a model atmosphere using the Transfer Function Model (Mayr et al., Space Sci. Rev., 54, 297-375, 1990) show that propagating waves originating in the thermosphere can excite a spectrum of gravity waves in the lower atmosphere. In spite of significantly reduced amplitudes but subject to amplification upon reflection in the upper troposphere, these gravity waves can provide a lift of unstable air to release instabilities in the troposphere thus initiating convection to form cloud/precipitation bands

  18. Incorporation of Solar Noble Gases from a Nebula-Derived Atmosphere During Magma Ocean Cooling

    NASA Technical Reports Server (NTRS)

    Woolum, D. S.; Cassen, P.; Wasserburg, G. J.; Porcelli, D.; DeVincenzi, Donald (Technical Monitor)

    1998-01-01

    The presence of solar noble gases in the deep interior of the Earth is inferred from the Ne isotopic compositions of MORB (Mid-ocean Ridge Basalts) and OIB (Oceanic Island Basalt); Ar data may also consistent with a solar component in the deep mantle. Models of the transport and distribution of noble gases in the earth's mantle allow for the presence of solar Ar/Ne and Xe/Ne ratios and permit the calculation of lower mantle noble gas concentrations. These mantle data and models also indicate that the Earth suffered early (0.7 to 2 x 10(exp 8) yr) and large (greater than 99 percent) losses of noble gases from the interior, a result previously concluded for atmospheric Xe. We have pursued the suggestion that solar noble gases were incorporated in the forming Earth from a massive, nebula-derived atmosphere which promoted large-scale melting, so that gases from this atmosphere dissolved in the magma ocean and were mixed downward. Models of a primitive atmosphere captured from the solar nebula and supported by accretion luminosity indicate that pressures at the Earth's surface were adequate (and largely more than the required 100 Atm) to dissolve sufficient gases. We have calculated the coupled evolution of the magma ocean and the overlying atmosphere under conditions corresponding to the cessation (or severe attenuation) of the sustaining accretion luminosity, prior to the complete removal of the solar nebula. Such a condition was likely to obtain, for instance, when most of the unaccumulated mass resided in large bodies which were only sporadically accreted. The luminosity supporting the atmosphere is then that provided by the cooling Earth, consideration of which sets a lower limit to the time required to solidify the mantle and terminate the incorporation of atmospheric gases within it. In our initial calculations, we have fixed the nebula temperature at To = 300K, a value likely to be appropriate for nebular temperatures at lAU in the early planet-building epoch

  19. Incorporation of Solar Noble Gases from a Nebula-Derived Atmosphere During Magma Ocean Cooling

    NASA Technical Reports Server (NTRS)

    Woolum, D. S.; Cassen, P.; Wasserburg, G. J.; Porcelli, D.; DeVincenzi, Donald (Technical Monitor)

    1998-01-01

    The presence of solar noble gases in the deep interior of the Earth is inferred from the Ne isotopic compositions of MORB (Mid-ocean Ridge Basalts) and OIB (Oceanic Island Basalt); Ar data may also consistent with a solar component in the deep mantle. Models of the transport and distribution of noble gases in the earth's mantle allow for the presence of solar Ar/Ne and Xe/Ne ratios and permit the calculation of lower mantle noble gas concentrations. These mantle data and models also indicate that the Earth suffered early (0.7 to 2 x 10(exp 8) yr) and large (greater than 99 percent) losses of noble gases from the interior, a result previously concluded for atmospheric Xe. We have pursued the suggestion that solar noble gases were incorporated in the forming Earth from a massive, nebula-derived atmosphere which promoted large-scale melting, so that gases from this atmosphere dissolved in the magma ocean and were mixed downward. Models of a primitive atmosphere captured from the solar nebula and supported by accretion luminosity indicate that pressures at the Earth's surface were adequate (and largely more than the required 100 Atm) to dissolve sufficient gases. We have calculated the coupled evolution of the magma ocean and the overlying atmosphere under conditions corresponding to the cessation (or severe attenuation) of the sustaining accretion luminosity, prior to the complete removal of the solar nebula. Such a condition was likely to obtain, for instance, when most of the unaccumulated mass resided in large bodies which were only sporadically accreted. The luminosity supporting the atmosphere is then that provided by the cooling Earth, consideration of which sets a lower limit to the time required to solidify the mantle and terminate the incorporation of atmospheric gases within it. In our initial calculations, we have fixed the nebula temperature at To = 300K, a value likely to be appropriate for nebular temperatures at lAU in the early planet-building epoch

  20. Atmospheric COCl2 measured by solar occultation spectrometry

    NASA Astrophysics Data System (ADS)

    Toon, G. C.; Blavier, J.-F.; Sen, B.; Drouin, B. J.

    Vertical profiles of atmospheric COCl2 (phosgene, carbonyl dichloride) have been measured remotely by the JPL MkIV interferometer during recent balloon flights. The v5 band of COCl2 in the 830 to 860 cm-1 spectral region was used for the analyses, despite its overlap with the stronger v4 band of CCl3F. Upper troposphere COCl2 volume mixing ratios of around 20 pptv were retrieved, increasing to 25 pptv by 15 km altitude, in good agreement with previous aircraft measurements made by in situ techniques. At mid-latitudes the COCl2 peaks at around 30 pptv at 22 km altitude, above which it rapidly drops, reaching zero by 28 km altitude.

  1. The Pre-penumbral Magnetic Canopy in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    MacTaggart, David; Guglielmino, Salvo L.; Zuccarello, Francesca

    2016-11-01

    Penumbrae are the manifestation of magnetoconvection in highly inclined (to the vertical direction) magnetic field. The penumbra of a sunspot tends to form, initially, along the arc of the umbra antipodal to the main region of flux emergence. The question of how highly inclined magnetic field can concentrate along the antipodal curves of umbrae, at least initially, remains to be answered. Previous observational studies have suggested the existence of some form of overlying magnetic canopy that acts as the progenitor for penumbrae. We propose that such overlying magnetic canopies are a consequence of how the magnetic field emerges into the atmosphere and are, therefore, part of the emerging region. We show, through simulations of twisted flux tube emergence, that canopies of highly inclined magnetic field form preferentially at the required locations above the photosphere.

  2. The Solar Photospheric Oxygen Abundance and the Role of 3D Model Atmospheres

    NASA Astrophysics Data System (ADS)

    Caffau, E.; Steffen, M.; Ludwig, H.-G.

    2008-09-01

    The solar oxygen abundance has undergone a major downward revision in the last decade, reputedly as a result of employing 3D hydrodynamical simulations to model the inhomogeneous structure of the solar photosphere. The very low oxygen abundance advocated by Asplund et al. 2004, A(O)=8.66, together with the downward revision of the abundances of other key elements, has created serious problems for solar models to explain the helioseismic measurements. In an effort to contribute to the dispute of whether the Sun has "solar" or "sub-solar" abundances, we have re-derived its photospheric abundance of oxygen, nitrogen, and other elements, independently of previous analyses. We applied a state-of-the art 3D (CO5BOLD) hydrodynamical simulation of the solar granulation as well as different 1D model atmospheres for the line by line spectroscopic abundance determinations. The analysis is based on both standard disk-center and full-disk spectral atlases; for oxygen we acquired in addition spectra at different heliocentric angles. The derived abundances are the result of equivalent width and/or line profile fitting of the available atomic lines. Our recommended oxygen abundance is A(O)=8.76+- 0.07, 0.1 dex higher than the value of Asplund et al. (2004). Our current estimate of the overall solar metallicity is 0.014< Z<0.016. Questions we discuss include: (i) Is the general downward revision of the solar abundances a 3D effect? (ii) How large are the abundance corrections due to horizontal inhomogeneities? (iii) What is the main reason for the differences between the abundances obtained in our study and those derived by Apslund and coworkers? (iv) How large are the uncertainties in the observed solar spectra? (v) What is the reason why the two forbidden oxygen lines, [OI] lambda 630 nm and [OI] lambda 636.3 nm, give significantly different answers for the solar oxygen abundance?

  3. High-Order Shock-Capturing Methods for Modeling Dynamics of the Solar Atmosphere

    NASA Technical Reports Server (NTRS)

    Bryson, Steve; Kosovichev, Alexander; Levy, Doron

    2004-01-01

    We use one-dimensional high-order central shock capturing numerical methods to study the response of various model solar atmospheres to forcing at the solar surface. The dynamics of the atmosphere is modeled with the Euler equations in a variable-sized flux tube in the presence of gravity. We study dynamics of the atmosphere suggestive of spicule formation and coronal oscillations. These studies are performed on observationally-derived model atmospheres above the quiet sun and above sunspots. To perform these simulations, we provide a new extension of existing second- and third- order shock-capturing methods to irregular grids. We also solve the problem of numerically maintaining initial hydrostatic balance via the introduction of new variables in the model equations and a careful initialization mechanism. We find several striking results: all model atmospheres respond to a single impulsive perturbation with several strong shock waves consistent with the rebound-shock model. These shock waves lift material and the transition region well into the initial corona, and the sensitivity of this lift to the initial impulse depends non-linearly on the details of the atmosphere model. We also reproduce an observed 3-minute coronal oscillation above sunspots compared to 5-minute oscillations above the quiet sun.

  4. The energy balance of plasmoids in the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Cargill, P. J.; Pneuman, G. W.

    1986-01-01

    The properties of an isolated magnetized plasmoid in a nonuniform magnetic field such as arises in stellar atmospheres are studied. The work of Pneuman and Cargill (1985) on the so-called melon-seed effect is extended to include an equation describing the energy balance, so giving a unified picture of the shape, motion, and energetics of the plasmoid. Three treatments of plasmoid energy balance are considered: (1) a polytropic law, (P = about N to the gamma); (2) one in which the plasmoid cools radiatively; and (3) one in which a heating function proportional to the local density balances the radiation. For a gamma = 4/3 polytrope the evolution is self-similar, so that the plasmoid maintains its shape as it moves out from the stellar surface. If gamma is less than 4/3, the final shape is a long thin cigar-shaped body, whereas if gamma is greater than or equal to 4/3, it ultimately becomes self-similar. In cases with radiation and also with heating, the ultimate shape of the plasmoid is determined by whether its gas or magnetic pressure dominate. The former is equivalent to the gamma-less-than-4/3 polytrope, and the latter to the gamma-greater-than-4/3 one. If radiation alone is present, the plasmoid cools rapidly and subsequently evolves self-similarly. If heating balances radiation initially, then the plasmoid heats up as it moves out, but, if the ratio of the transit of time of Alfven waves across it is much less than the radiative cooling time, it ultimately evolves as a gamma = 5/3 polytrope. In each case the plasmoid can be ejected to large distances (several radii) in a stellar atmosphere, for a reasonable choice of surface parameters.

  5. The energy balance of plasmoids in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Cargill, P. J.; Pneuman, G. W.

    1986-08-01

    The properties of an isolated magnetized plasmoid in a nonuniform magnetic field such as arises in stellar atmospheres are studied. The work of Pneuman and Cargill (1985) on the so-called melon-seed effect is extended to include an equation describing the energy balance, so giving a unified picture of the shape, motion, and energetics of the plasmoid. Three treatments of plasmoid energy balance are considered: (1) a polytropic law, (P = about N to the gamma); (2) one in which the plasmoid cools radiatively; and (3) one in which a heating function proportional to the local density balances the radiation. For a gamma = 4/3 polytrope the evolution is self-similar, so that the plasmoid maintains its shape as it moves out from the stellar surface. If gamma is less than 4/3, the final shape is a long thin cigar-shaped body, whereas if gamma is greater than or equal to 4/3, it ultimately becomes self-similar. In cases with radiation and also with heating, the ultimate shape of the plasmoid is determined by whether its gas or magnetic pressure dominate. The former is equivalent to the gamma-less-than-4/3 polytrope, and the latter to the gamma-greater-than-4/3 one. If radiation alone is present, the plasmoid cools rapidly and subsequently evolves self-similarly. If heating balances radiation initially, then the plasmoid heats up as it moves out, but, if the ratio of the transit of time of Alfven waves across it is much less than the radiative cooling time, it ultimately evolves as a gamma = 5/3 polytrope. In each case the plasmoid can be ejected to large distances (several radii) in a stellar atmosphere, for a reasonable choice of surface parameters.

  6. Mars atmospheric losses induced by the solar wind: Comparison of observations with models

    NASA Astrophysics Data System (ADS)

    Vaisberg, Oleg

    2015-12-01

    With new results from Mars-Express on plasma environment of Mars and two new Mars satellites the study Martian atmospheric losses receives new attention. Paper summarizes experimental results concentrating on configuration of Martian magnetosphere and the measurements of planetary ion escape induced by the solar wind. Several plasma populations constituting solar wind induced mass loss have been identified and studied: pick-up ions in shocked solar wind flow and induced (accretion) tail, ions accelerated in the tail current sheet, and outflow of ionospheric ions. Measured ion flux values and calculations of the total escape rate including solar cycle variations are summarized. Several types of simulation of the solar wind with Mars are considered and results of representative models are given and compared with experimental results. These computer models allowed one to much better understand solar wind-Mars interaction. However, there is significant difference between total loss rates obtained from simulation and ones from measurements on the spacecraft. Both measurements and simulation provide significant flux values that are considered as an important factor of mass loss during cosmogonic time of the planet. The origin of each solar wind induced loss component and its contribution to total amount are discussed and compared with relevant computer models. Future progress in experiments and simulation is briefly discussed.

  7. Helium 584 Å and H Lyman-α Airglow in Giant Planetary Atmospheres: Modeling, Observations, and Implications

    NASA Astrophysics Data System (ADS)

    Parkinson, Christopher; Esposito, Larry W.

    2016-07-01

    The atmosphere of the outer planets is mainly composed of H2 and neutral atomic helium. The study of He 584 Å and H Lyman-α brightnesses is interesting as the EUV and FUV (Extreme and Far Ultraviolet) planetary airglow have the potential to yield useful information about mixing and other important parameters in their thermospheres. Time variation, asymmetries, and polar enhancement of the airglow are also possible and analysis of the public archived NASA mission data sets (i.e. Voyager and Cassini) can help solve some of the outstanding problems associated with these phenomena. The comparison of observations with results from sophisticated photochemical and radiative transfer models can also help ameliorate unexplained differences in the dynamical processes operating within planetary upper atmospheres. Powerful analysis techniques allow us to extract information on atmospheric mixing, temperatures, and temporal changes due to the solar and seasonal cycles from the variations in distribution and intensity of airglow emissions that result. The presentation will discuss the implications of interpretations from comparison of modeling and observations in giant planetary atmospheres.

  8. The generation and damping of propagating MHD kink waves in the solar atmosphere

    SciTech Connect

    Morton, R. J.; Verth, G.; Erdélyi, R.; Hillier, A. E-mail: g.verth@sheffield.ac.uk

    2014-03-20

    The source of the non-thermal energy required for the heating of the upper solar atmosphere to temperatures in excess of a million degrees and the acceleration of the solar wind to hundreds of kilometers per second is still unclear. One such mechanism for providing the required energy flux is incompressible torsional Alfvén and kink magnetohydrodynamic (MHD) waves, which are magnetically dominated waves supported by the Sun's pervasive and complex magnetic field. In particular, propagating MHD kink waves have recently been observed to be ubiquitous throughout the solar atmosphere, but, until now, critical details of the transport of the kink wave energy throughout the Sun's atmosphere were lacking. Here, the ubiquity of the waves is exploited for statistical studies in the highly dynamic solar chromosphere. This large-scale investigation allows for the determination of the chromospheric kink wave velocity power spectra, a missing link necessary for determining the energy transport between the photosphere and corona. Crucially, the power spectra contain evidence for horizontal photospheric motions being an important mechanism for kink wave generation in the quiescent Sun. In addition, a comparison with measured coronal power spectra is provided for the first time, revealing frequency-dependent transmission profiles, suggesting that there is enhanced damping of kink waves in the lower corona.

  9. Empirical determination of solar proton access to the atmosphere: Impact on polar flight paths

    NASA Astrophysics Data System (ADS)

    Neal, Jason J.; Rodger, Craig J.; Green, Janet C.

    2013-07-01

    Violent expulsions on the Sun's surface release high energy solar protons that ultimately affect HF communication used by aircraft. The geomagnetic field screens the low altitude equatorial region, but these protons can access the atmosphere over the poles. The latitudes over which the solar protons can reach vary with geomagnetic indices such as Kp and Dst. In this study we use observations from low Earth orbit to determine the atmospheric access of solar protons and hence the flights paths most likely to be affected. Observations taken by up to six polar orbiting satellites during 15 solar proton events are analyzed. From this we determine 16,850 proton rigidity cutoff estimates across three energy channels. Empirical fits are undertaken to estimate the most likely behavior of the cutoff dependence with geomagnetic activity. The changing Kp value is found to lead the variation in the cutoffs by 3 h. We provide simple equations by which the geomagnetic latitude at which the protons impact the atmosphere can be determined from a given Kp or Dst value. The variation found in the cutoff with Kp is similar to that used in existing operational models, although we suggest that a 1-2° equatorward shift in latitude would provide greater accuracy. We find that a Kp predictive model can provide additional warning to the variation in proton cutoffs. Hence, a prediction of the cutoff latitudes can be made 3 h to as much as 7 h into the future, meeting suggested minimum planning times required by the aviation industry.

  10. RETURN CURRENTS AND ENERGY TRANSPORT IN THE SOLAR FLARING ATMOSPHERE

    SciTech Connect

    Codispoti, Anna; Torre, Gabriele; Piana, Michele; Pinamonti, Nicola

    2013-08-20

    According to the standard Ohmic perspective, the injection of accelerated electrons into the flaring region violates local charge equilibrium and therefore, in response, return currents are driven by an electric field to equilibrate such charge violation. In this framework, the energy loss rate associated with these local currents has an Ohmic nature and significantly shortens the accelerated electron path. In the present paper, we adopt a different viewpoint and, specifically, we study the impact of the background drift velocity on the energy loss rate of accelerated electrons in solar flares. We first utilize the Rutherford cross-section to derive the formula of the energy loss rate when the collisional target has a finite temperature and the background instantaneously and coherently moves up to equilibrate the electron injection. We then use the continuity equation for electrons and imaging spectroscopy data provided by RHESSI to validate this model. We show that this new formula for the energy loss rate provides a better fit of the experimental data with respect to the model based on the effects of standard Ohmic return currents.

  11. Ground-Based Multifunctional Radiometric Complex for Atmospheric and Solar Radiation Measurements at the Kishinev Site, Moldova

    NASA Astrophysics Data System (ADS)

    Aculinin, A.; Smirnov, A.; Smicov, V.; Eck, T.; Policarpov, A.; Grachev, V.

    2004-06-01

    The information about the ground-based multifunctional radiometric complex is presented. Radiometric complex is designated to make a high quality long-term continuous monitoring of the solar and atmospheric radiation and to collect datasets with the solar radiation broadband measurements from UV-B to IR. Complex is placed in an urban environment at the Kishinev site. Solar radiation data are supplied with the main meteorological elements such as air temperature, relative humidity, atmospheric pressure, wind mean velocity and direction, and solar irradiances, which are continuously measured with the automatic meteorological station. Measurements of the total column ozone content with the MICROTOPS II Ozonemeter are regularly fulfilled at the Kishinev site. Results of measurements of the solar and atmospheric radiation and total ozone content in the column of atmosphere are originally presented for the Kishinev site of observation.

  12. Solar energy in buildings: Implications for California energy policy

    NASA Technical Reports Server (NTRS)

    Hirshberg, A. S.; Davis, E. S.

    1977-01-01

    An assessment of the potential of active solar energy systems for buildings in California is summarized. The technology used for solar heating, cooling, and water heating in buildings is discussed. The major California weather zones and the solar energy designs are described, as well as the sizing of solar energy systems and their performance. The cost of solar energy systems is given both at current prices and at prices consistent with optimistic estimates for the cost of collectors. The main institutional barriers to the wide spread use of solar energy are summarized.

  13. Atmospheric Effects of Solar Energetic Particle Events In Magnetized and Non-Magnetized Regions of Mars

    NASA Astrophysics Data System (ADS)

    Jolitz, R.; Dong, C.; Lillis, R. J.; Curry, S.; Brain, D. A.; Larson, D. E.

    2015-12-01

    Solar and shock-accelerated heliospheric energetic charged particles represent an important if irregular source of energy to the Martian upper atmosphere. A Monte Carlo code has been developed to track a population of protons in an atmosphere and account for energy loss to collisional processes including heating, ionization, excitation, and charge transfer. The model framework is open to multiple planetary-specific inputs (e.g. three-dimensional neutral densities, electric and magnetic fields) and uses an adaptive trace algorithm to accurately model collisions in dense and sparse atmospheric regions. Applying 3-D models of electric and magnetic fields from the Michigan Mars MHD code and 1-D neutral densities from the Mars Global Thermosphere Ionosphere Model (M-GITM), we use this model to calculate volume rates of relevant proton-mediated energy loss processes in the Martian upper atmosphere. The model will be improved to generate ionization and heating rates in areas of strong and weak crustal magnetic fields for solar energetic particle events observed by the SEP instrument on MAVEN. Ultimately this will form part of a comprehensive model of solar wind interactions with Mars.

  14. Rocket Measurements of the Direct Solar Lyman-alpha Radiation Penetrating in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Guineva, V. H.; Witt, G.; Gumbel, J.; Khaplanov, M.; Tashev, V. L.

    2006-03-01

    The resonance transition 2P-2S of the atomic hydrogen (Lyman-alpha emission) is the strongest and most conspicuous feature in the solar EUV spectrum. The Lyman-alpha radiation transfer depends on the resonance scattering from the hydrogen atoms in the atmosphere and on the O2 absorption. Since the Lyman-alpha extinction in the atmosphere is a measure for the column density of the oxygen molecules, the atmospheric temperature profile can be calculated thereof. Rocket measurements of the direct Lyman-alpha radiation vertical profile in the summer mesosphere and thermosphere (up to 120 km), at high latitudes will be carried out in June 2006. The Lyman-alpha flux will be registered by a detector of solar Lyman-alpha radiation, manufactured in the Stara Zagora Department of the Solar-Terrestrial Influences Laboratory (STIL BAS). Its basic part is an ionization camera, filled in with NO. The scientific data analysis will include raw data reduction, radiative transfer simulations, temperature retrieval as well as co-analysis with other parameters, measured near the polar summer mesopause. This project is a scientific cooperation between STIL-BAS, Stara Zagora Department and the Atmospheric Physics Group at the Department of Meteorology (MISU), Stockholm University, Sweden. The joint project is part from the rocket experiment HotPay I, in the ALOMAR eARI Project, EU's 6th Framework Programme, Andoya Rocket Range, Andenes, Norway.

  15. Carbon monoxide on Jupiter and implications for atmospheric convection

    NASA Technical Reports Server (NTRS)

    Prinn, R. G.; Barshay, S. S.

    1977-01-01

    A study of the equilibrium and disequilibrium thermochemistry of the recently discovered carbon monoxide on Jupiter suggests that the presence of this gas in the visible atmosphere is a direct result of very rapid upward mixing from levels in the deep atmosphere where the temperature is about 1100 K and where carbon monoxide is thermodynamically much more stable. As a consequence the observed carbon monoxide mixing ratio is a sensitive function of the vertical eddy mixing coefficient. We infer a value for this latter coefficient which is about three to four orders of magnitude greater than that in the earth's troposphere. This result directly supports existing structural and dynamical theories implying very rapid convection in the deep Jovian atmosphere, driven by an internal heat source.

  16. On the physics of waves in the solar atmosphere: Wave heating and wind acceleration

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.

    1992-01-01

    In the area of solar physics, new calculations of the acoustic wave energy fluxes generated in the solar convective zone was performed. The original theory developed was corrected by including a new frequency factor describing temporal variations of the turbulent energy spectrum. We have modified the original Stein code by including this new frequency factor, and tested the code extensively. Another possible source of the mechanical energy generated in the solar convective zone is the excitation of magnetic flux tube waves which can carry energy along the tubes far away from the region. The problem as to how efficiently those waves are generated in the Sun was recently solved. The propagation of nonlinear magnetic tube waves in the solar atmosphere was calculated, and mode coupling, shock formation, and heating of the local medium was studied. The wave trapping problems and evaluation of critical frequencies for wave reflection in the solar atmosphere was studied. It was shown that the role played by Alfven waves in the wind accelerations and the coronal hole heating is dominant. Presently, we are performing calculations of wave energy fluxes generated in late-type dwarf stars and studying physical processes responsible for the heating of stellar chromospheres and coronae. In the area of physics of waves, a new analytical approach for studying linear Alfven waves in smoothly nonuniform media was recently developed. This approach is presently being extended to study the propagation of linear and nonlinear magnetohydrodynamic (MHD) waves in stratified, nonisothermal and solar atmosphere. The Lighthill theory of sound generation to nonisothermal media (with a special temperature distribution) was extended. Energy cascade by nonlinear MHD waves and possible chaos driven by these waves are presently considered.

  17. Rarefield gas flows through meshes and implications for atmospheric measurements

    NASA Astrophysics Data System (ADS)

    Gumbel, J.

    2001-05-01

    Meshes are commonly used as part of instruments for in situ atmospheric measurements. This study analyses the aerodynamic effect of meshes by means of wind tunnel experiments and numerical simulations. Based on the Direct Simulation Monte Carlo method, a simple mesh parameterisation is described and applied to a number of representative flow conditions. For open meshes freely exposed to the flow, substantial compression effects are found both upstream and downstream of the mesh. Meshes attached to close instrument structures, on the other hand, cause only minor flow disturbances. In an accompanying paper, the approach developed here is applied to the quantitative analysis of rocket-borne density measurements in the middle atmosphere.

  18. The possible origin of facular brightness in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Kostik, R.; Khomenko, E.

    2016-05-01

    This paper studies the dependence of the Ca ii H line core brightness on the strength and inclination of the photospheric magnetic field, and on the parameters of convective and wave motions in a facular region at the center of the solar disc. We use three simultaneous data sets that were obtained at the German Vacuum Tower Telescope (Observatorio del Teide, Tenerife): (1) spectra of Ba ii 4554 Å line, registered with the instrument TESOS to measure the variations of intensity and velocity through the photosphere up to the temperature minimum; (2) spectropolarimetric data in Fe i 1.56 μm lines (registered with the instrument TIP II) to measure photospheric magnetic fields; (3) filtergrams in Ca ii H that give information about brightness fluctuations in the chromosphere. The results show that the Ca ii H brightness in the facula strongly depends on the power of waves with periods in the 5-min range, which propagate upwards, and also on the phase shift between velocity oscillations at the bottom photosphere and around the temperature minimum height that is measured from Ba ii line. The Ca ii H brightness is maximum at locations where the phase shift between temperature and velocity oscillations lies within 0°-100°. There is an indirect influence of convective motions on the Ca ii H brightness. The higher the amplitude of convective velocities is and the greater the height is where they change their direction of motion, the brighter the facula. In summary, our results lead to conclusions that facular regions appear bright not only because of the Wilson depression in magnetic structures, but also owing to real heating.

  19. Minimal Magnetic States of the Sun and the Solar Wind: Implications for the Origin of the Slow Solar Wind

    NASA Astrophysics Data System (ADS)

    Cliver, E. W.; von Steiger, R.

    2017-09-01

    During the last decade it has been proposed that both the Sun and the solar wind have minimum magnetic states, lowest order levels of magnetism that underlie the 11-yr cycle as well as longer-term variability. Here we review the literature on basal magnetic states at the Sun and in the heliosphere and draw a connection between the two based on the recent deep 2008-2009 minimum between cycles 23 and 24. In particular, we consider the implications of the low solar activity during the recent minimum for the origin of the slow solar wind.

  20. Influence of the solar wind variability on atmospheric processes in the southern polar region

    NASA Astrophysics Data System (ADS)

    Troshichev, O.; Egorova, L.; Vovk, V.

    Fluxes of galactic cosmic rays altered by solar wind and spikes of solar cosmic rays are usually examined as one possible mechanism of solar activity influencing the Earth's atmosphere. To study effects of the solar wind variability the daily data of aerological sounding carried out at the Antarctic station Vostok ( = 78°27S,= 106°52E) have been examined in the analysis. Vostok station is located at the ice flat homogeneous plain at height of 3.5 km, inland 1500 km from the coast, and is not subjected to local atmospheric vortices. The catabatic type of atmospheric circulation (i.e. vertical type of circulation) is typical of the central part of Antarctic, where the stratosphere cold air masses go down to ice dome and then flow along the dome surface toward the cost. All of these circumstances allow the Vostok station location act like a window into the nature of the nighttime middle atmosphere where solar influences are stronger than in the lower atmosphere. The detail analysis of the Vostok data for 1978-1992 made it possible to conclude that dramatic changes of the troposphere temperature, observed in the Southern near-pole region in relation to the interplanetary shocks, accompanying Forbush decreases (FD) and solar protons events (SPE), are caused, in actuality, by sharp changes of the IMF Bz component typical of interplanetary shocks, and by the corresponding fluctuations of the interplanetary electric field (ESW ). The warming is observed at altitudes h<5 km and cooling at h>10 km when changes in the IMF B Z component are negative and ESW increases. The regularity is especially supported by the fact that opposite temperature deviations are observed in relation with the northward BZ leaps. There is a linear relationship between the value ofE SW and ground temperature at Vostok station: the larger leap in the E W the stronger is temperature deviation. The effect reachesS maximum within one day and is damped equally quickly. It is suggested that electric

  1. Empirical mode decomposition analysis of random processes in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Kolotkov, D. Y.; Anfinogentov, S. A.; Nakariakov, V. M.

    2016-08-01

    Context. Coloured noisy components with a power law spectral energy distribution are often shown to appear in solar signals of various types. Such a frequency-dependent noise may indicate the operation of various randomly distributed dynamical processes in the solar atmosphere. Aims: We develop a recipe for the correct usage of the empirical mode decomposition (EMD) technique in the presence of coloured noise, allowing for clear distinguishing between quasi-periodic oscillatory phenomena in the solar atmosphere and superimposed random background processes. For illustration, we statistically investigate extreme ultraviolet (EUV) emission intensity variations observed with SDO/AIA in the coronal (171 Å), chromospheric (304 Å), and upper photospheric (1600 Å) layers of the solar atmosphere, from a quiet sun and a sunspot umbrae region. Methods: EMD has been used for analysis because of its adaptive nature and essential applicability to the processing non-stationary and amplitude-modulated time series. For the comparison of the results obtained with EMD, we use the Fourier transform technique as an etalon. Results: We empirically revealed statistical properties of synthetic coloured noises in EMD, and suggested a scheme that allows for the detection of noisy components among the intrinsic modes obtained with EMD in real signals. Application of the method to the solar EUV signals showed that they indeed behave randomly and could be represented as a combination of different coloured noises characterised by a specific value of the power law indices in their spectral energy distributions. On the other hand, 3-min oscillations in the analysed sunspot were detected to have energies significantly above the corresponding noise level. Conclusions: The correct accounting for the background frequency-dependent random processes is essential when using EMD for analysis of oscillations in the solar atmosphere. For the quiet sun region the power law index was found to increase

  2. SYSTEMATIC DE-SATURATION OF IMAGES FROM THE ATMOSPHERIC IMAGING ASSEMBLY IN THE SOLAR DYNAMICS OBSERVATORY

    SciTech Connect

    Schwartz, R. A.; Torre, G.; Piana, M. E-mail: torre@dima.unige.it

    2014-10-01

    Extreme ultraviolet (EUV) images of solar flares provided by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) are often affected by saturation effects in their core, physically most interesting, region. We introduce an image reconstruction procedure that allows recovering information in the primary saturation domain using the secondary images produced by the diffraction fringes as input data. Such a procedure is based on standard image-processing tools like correlation, convolution, and back-projection. Its effectiveness is tested in the case of AIA/SDO observations of the 2013 July 8 flaring event.

  3. THERMAL FINE STRUCTURE AND MAGNETIC FIELDS IN THE SOLAR ATMOSPHERE: SPICULES AND FIBRILS

    SciTech Connect

    Judge, Philip G.; Low, Boon Chye; Tritschler, Alexandra E-mail: low@ucar.edu

    2011-03-20

    The relationship between observed structures in the solar atmosphere and the magnetic fields threading them is known only for the solar photosphere, even then imprecisely. We suggest that some of the fine structures in the more tenuous chromosphere and corona-specifically some populations of spicules and fibrils-correspond to warps in two-dimensional sheet-like structures, as an alternative to conventional interpretations in terms of tube-like structures. The sheets are perhaps related to magnetic tangential discontinuities, which Parker has argued arise naturally in low-{beta} conditions. Some consequences of this suggestion, if it can be confirmed, are discussed.

  4. Atmospheric extinction in solar tower plants: absorption and broadband correction for MOR measurements

    NASA Astrophysics Data System (ADS)

    Hanrieder, N.; Wilbert, S.; Pitz-Paal, R.; Emde, C.; Gasteiger, J.; Mayer, B.; Polo, J.

    2015-08-01

    Losses of reflected Direct Normal Irradiance due to atmospheric extinction in concentrated solar tower plants can vary significantly with site and time. The losses of the direct normal irradiance between the heliostat field and receiver in a solar tower plant are mainly caused by atmospheric scattering and absorption by aerosol and water vapor concentration in the atmospheric boundary layer. Due to a high aerosol particle number, radiation losses can be significantly larger in desert environments compared to the standard atmospheric conditions which are usually considered in ray-tracing or plant optimization tools. Information about on-site atmospheric extinction is only rarely available. To measure these radiation losses, two different commercially available instruments were tested, and more than 19 months of measurements were collected and compared at the Plataforma Solar de Almería. Both instruments are primarily used to determine the meteorological optical range (MOR). The Vaisala FS11 scatterometer is based on a monochromatic near-infrared light source emission and measures the strength of scattering processes in a small air volume mainly caused by aerosol particles. The Optec LPV4 long-path visibility transmissometer determines the monochromatic attenuation between a light-emitting diode (LED) light source at 532 nm and a receiver and therefore also accounts for absorption processes. As the broadband solar attenuation is of interest for solar resource assessment for concentrated solar power (CSP), a correction procedure for these two instruments is developed and tested. This procedure includes a spectral correction of both instruments from monochromatic to broadband attenuation. That means the attenuation is corrected for the time-dependent solar spectrum which is reflected by the collector. Further, an absorption correction for the Vaisala FS11 scatterometer is implemented. To optimize the absorption and broadband correction (ABC) procedure, additional

  5. Analysis of Radon Decay Data and its Implications for Physics, Geophysics, and Solar Physics.

    NASA Astrophysics Data System (ADS)

    Sturrock, Peter A.; Fischbach, E.; Jenkins, J. H.; Steinitz, G.

    2012-05-01

    We present an analysis of about 29,000 measurements of gamma radiation associated with the decay of radon in a sealed container at the Geological Survey of Israel (GSI) Laboratory in Jerusalem between January 28 2007 and May 10 2010. These measurements exhibit strong variations in time of year and time of day, which may be due in part to environmental influences. However, time-series analysis also reveals a number of periodicities, notably at 11.2 year-1 and 12.5 year-1, which we have found in other nuclear-decay data --including data acquired at the Brookhaven National Laboratory and the Physiklisch-Technische Bundesanstalt-- which we attribute to a solar influence. A distinct property of the GSI results is that the annual oscillation is much stronger in daytime data than in nighttime data, but the opposite is true for all other oscillations. We speculate on possible interpretations of this curious result. Solar neutrinos remain our prime suspect as the agent responsible for beta-decay anomalies. These results have implications for physics (that nuclear decay rates are not constant and may be stimulated); for geophysics (that the variability of radon measurements cannot be ascribed entirely to atmospheric and solid-earth processes); and for solar physics (that the Sun contains an inner tachocline, separating a slowly rotating core from the radiative zone, which has properties similar to those of the outer tachocline separating the radiative zone from the convection zone). This work was supported by DOE grant DE-AC-02-76ER071428.

  6. International Solar Cycle Studies [ISCS] Working Group 2: solar magnetic field variability - from the lower atmosphere through the inner corona

    NASA Astrophysics Data System (ADS)

    Harrison, Richard A.; Michels, Donald

    This report is a summary of activities and plans relating to the International Solar Cycle Studies (ISCS) Working Group 2, which is concerned with solar magnetic field variability, from the lower atmosphere through the inner corona. Whilst the Working Group carries a rather general title, the activities are focusing on several well defined topics - in particular the onset of coronal mass ejection events. Recognising the large number of scientific meetings worldwide, the working style of this group is aimed at improving communication, information exchange and collaboration making use of existing meetings and with a minimum of red tape. The core of the activity is through the use of the World Wide Web and e-mail. In this way, this Working Group does not introduce extra effort, but provides a better focus for on-going projects.

  7. Magnetohydrodynamics of atmospheric transients. III - Basic results of nonplane two-dimensional analysis. [of solar flares effect on solar atmosphere

    NASA Technical Reports Server (NTRS)

    Nakagawa, Y.; Wu, S. T.; Han, S. M.

    1981-01-01

    The dynamic response of a stratified atmosphere permeated by a magnetic field to a sudden localized energy release (e.g., the onset of a flare) is examined in a physically self-consistent manner within the approximation of axisymmetric two-dimensional magnetohydrodynamics. In contrast to the previous plane analyses, with the inclusion of out-of-plane components of magnetic and velocity fields, it is shown that the presence of transverse waves leads to spiraling material motions and formation of ring current with open (mostly radial) magnetic field configuration. In the closed (mostly azimuthal) magnetic field, the evolutionary response of a magnetic field is shown to follow the typical sequence observed with a flare, namely, the relaxations of magnetic shear toward the potential configuration. The details of the results are described with discussions on their physical significance.

  8. Monte Carlo Simulation of Solar Reflectances for Cloudy Atmospheres.

    NASA Astrophysics Data System (ADS)

    Barker, H. W.; Goldstein, R. K.; Stevens, D. E.

    2003-08-01

    Monte Carlo simulations of solar radiative transfer were performed for a well-resolved, large, three-dimensional (3D) domain of boundary layer cloud simulated by a cloud-resolving model. In order to represent 3D distributions of optical properties for 2 × 106 cloudy cells, attenuation by droplets was handled by assigning each cell a cumulative distribution of extinction derived from either a model or an assumed discrete droplet size spectrum. This minimizes the required number of detailed phase functions. Likewise, to simulate statistically significant, high-resolution imagery, it was necessary to apply variance reduction techniques. Three techniques were developed for use with the local estimation method of computing reflectance . First, small fractions of come from numerous, small contributions of computed at each scattering event. Terminating calculation of when it falls below min 103 was found to impact estimates of minimally but reduced computation time by 10%. Second, large fractions of come from infrequent realizations of large . When sampled poorly, they boost Monte Carlo noise significantly. Removing max, storing them in a domainwide reservoir, adding max to local estimates of , and, at simulation's end, distributing the reservoir across the domain in proportion to local , tends to reduce variance much. This regionalization technique works well when the number of photons per unit area is small (nominally 50 000). A value of max 100 reduces variance of greatly with little impact on estimates of . Third, if

  9. Atmospheric Mining in the Outer Solar System: Aerial Vehicle Mission and Design Issues

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2015-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and deuterium can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and deuterium were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate, storage options, and different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of additional exploration and exploitation vehicles exists. The mining aerospacecraft (ASC) could fly through the outer planet atmospheres, for global weather observations, localized storm or other disturbance investigations, wind speed measurements, polar observations, etc. Analyses of orbital transfer vehicles (OTVs), landers, and in-situ resource utilization (ISRU) mining factories are included. Preliminary observations are presented on near-optimal selections of moon base orbital locations, OTV power levels, and OTV and lander rendezvous points.

  10. Electromechanical coupling of the solar atmosphere; Proceedings of the OSL Workshop, Capri, Italy, May 27-31, 1991

    NASA Technical Reports Server (NTRS)

    Spicer, Daniel S. (Editor); Macneice, Peter (Editor)

    1992-01-01

    The present conference discusses the role of magnetic flux tubes as communication channels, flux tube sizes and their temporal evolution, magnetic field line topology in the solar active regions, weak solar magnetic fields, explosive events and magnetic reconnection in the solar atmosphere, and 3D kinematic reconnection of plasmoids with nulls. Also discussed are coronal heating mechanisms, coronal heating through a lack of MHD equilibrium, Alfven waves in current-carrying inhomogeneous plasmas, hydrostatic models of X-ray coronal loops, MHD turbulence in an expanding atmosphere, and hot mass transport in the solar active prominence.

  11. Interior and its implications for the atmosphere. [effects of Titan interior structure on its atmospheric composition

    NASA Technical Reports Server (NTRS)

    Lewis, J. S.

    1974-01-01

    The bulk composition and interior structure of Titan required to explain the presence of a substantial methane atmosphere are shown to imply the presence of solid CH4 - 7H2O in Titan's primitive material. Consideration of the possible composition and structure of the present atmosphere shows plausible grounds for considering models with total atmospheric pressures ranging from approximately 20 mb up to approximately 1 kb. Expectations regarding the physical state of the surface and its chemical composition are strongly conditioned by the mass of atmosphere believed to be present. A surface of solid CH4, liquid CH4 solid, CH4 hydrate, H2O ice, aqueous NH3 solution, or even a non-surface of supercritical H2O-NH3-CH4 fluid could be rationalized.

  12. Finding Atmospheres of Extra-Solar Planets in High-Dispersion Near-Infrared Spectra

    NASA Astrophysics Data System (ADS)

    Käufl, Hans Ulrich

    In the wavelength regime of 950-5500nm CRIRES, ESO's Cryogenic Infrared Echelle Spectrograph will offer a spectral resolution λ/Δλ ≈ 10^5 in combination with a spatial resolution of 0.2^''. This makes it well suited to search for spectral signatures of atmospheres of extra-solar planets. Sensitivity estimates for the detection of the non-thermal OH glow in oxygen-bearing atmospheres are given. With the VLT such a search is still sensitivity limited, but a dedicated spectrograph at the projected ESO 100m OWL telescope could detect Earth-like planets at a distance of ≈ 5 parsec.

  13. Absorption of solar energy heats up our planet's surface and the atmosphere and makes life for us po

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Credit: Image courtesy Barbara Summey, NASA Goddard Visualization Analysis Lab, based upon data processed by Takmeng Wong, CERES Science Team, NASA Langley Research Center Satellite: Terra Sensor: CERES Image Date: 09-30-2001 VE Record ID: 11546 Description: Absorption of solar energy heats up our planet's surface and the atmosphere and makes life for us possible. But the energy cannot stay bound up in the Earth's environment forever. If it did then the Earth would be as hot as the Sun. Instead, as the surface and the atmosphere warm, they emit thermal longwave radiation, some of which escapes into space and allows the Earth to cool. This false-color image of the Earth was produced on September 30, 2001, by the Clouds and the Earth's Radiant Energy System (CERES) instrument flying aboard NASA's Terra spacecraft. The image shows where more or less heat, in the form of longwave radiation, is emanating from the top of Earth's atmosphere. As one can see in the image, the thermal radiation leaving the oceans is fairly uniform. The blue swaths across the central Pacific represent thick clouds, the tops of which are so high they are among the coldest places on Earth. In the American Southwest, which can be seen in the upper righthand corner of the globe, there is often little cloud cover to block outgoing radiation and relatively little water to absorb solar energy. Consequently, the amount of outgoing radiation in the American Southwest exceeds that of the oceans. Also, that region was experiencing an extreme heatwave when these data were acquired. Recently, NASA researchers discovered that incoming solar radiation and outgoing thermal radiation increased in the tropics from the 1980s to the 1990s. (Click to read the press release .) They believe that the reason for the unexpected increase has to do with an apparent change in circulation patterns around the globe, which effectively reduced the amount of water vapor and cloud cover in the upper reaches of the atmosphere

  14. Absorption of solar energy heats up our planet's surface and the atmosphere and makes life for us po

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Credit: Image courtesy Barbara Summey, NASA Goddard Visualization Analysis Lab, based upon data processed by Takmeng Wong, CERES Science Team, NASA Langley Research Center Satellite: Terra Sensor: CERES Image Date: 09-30-2001 VE Record ID: 11546 Description: Absorption of solar energy heats up our planet's surface and the atmosphere and makes life for us possible. But the energy cannot stay bound up in the Earth's environment forever. If it did then the Earth would be as hot as the Sun. Instead, as the surface and the atmosphere warm, they emit thermal longwave radiation, some of which escapes into space and allows the Earth to cool. This false-color image of the Earth was produced on September 30, 2001, by the Clouds and the Earth's Radiant Energy System (CERES) instrument flying aboard NASA's Terra spacecraft. The image shows where more or less heat, in the form of longwave radiation, is emanating from the top of Earth's atmosphere. As one can see in the image, the thermal radiation leaving the oceans is fairly uniform. The blue swaths across the central Pacific represent thick clouds, the tops of which are so high they are among the coldest places on Earth. In the American Southwest, which can be seen in the upper righthand corner of the globe, there is often little cloud cover to block outgoing radiation and relatively little water to absorb solar energy. Consequently, the amount of outgoing radiation in the American Southwest exceeds that of the oceans. Also, that region was experiencing an extreme heatwave when these data were acquired. Recently, NASA researchers discovered that incoming solar radiation and outgoing thermal radiation increased in the tropics from the 1980s to the 1990s. (Click to read the press release .) They believe that the reason for the unexpected increase has to do with an apparent change in circulation patterns around the globe, which effectively reduced the amount of water vapor and cloud cover in the upper reaches of the atmosphere

  15. Understanding Measures of Magnetic Activity Using Physics-based Models of the Solar Interior and Atmosphere

    NASA Astrophysics Data System (ADS)

    Abbett, W. P.; Luhmann, J. G.

    2014-12-01

    Substantial progress has been made over the past decade in the effort to better understand how magnetic flux and energy is generated in the convective interior of the Sun, how it emerges into the solar atmosphere, and how manifestations of solar magnetic activity (such as sunspots, coronal mass ejections, and flares) are connected within a dynamic magnetic environment spanning the solar convection zone-to-corona system. Here, we present a brief overview of recent efforts to model the evolution of active region magnetic fields and sunspots over a range of physical conditions and spatial and temporal scales. We will focus on how dynamic, physics-based numerical models can be used to better understand observed relationships between different measures of solar activity as a function of time (e.g., sunspot activity and morphologies, unsigned magnetic flux measured at the photosphere, coronal X-ray emissivity). We will determine whether local physics-based models of active region evolution can be used to better constrain proxies of solar activity such as the sunspot number, which remains the only direct record available to trace the very long-term influence of the solar dynamo on the earth's environment.

  16. Results of aperture area comparisons for exo-atmospheric total solar irradiance measurements.

    PubMed

    Johnson, B Carol; Litorja, Maritoni; Fowler, Joel B; Shirley, Eric L; Barnes, Robert A; Butler, James J

    2013-11-20

    Exo-atmospheric solar irradiance measurements made by the solar irradiance community since 1978 have incorporated limiting apertures with diameters measured by a number of metrology laboratories using a variety of techniques. Knowledge of the aperture area is a critical component in the conversion of radiant flux measurements to solar irradiance. A National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) sponsored international comparison of aperture area measurements of limiting apertures provided by solar irradiance researchers was performed, the effort being executed by the National Institute of Standards and Technology (NIST) in coordination with the EOS Project Science Office. Apertures that had institutional heritage with historical solar irradiance measurements were measured using the absolute aperture measurement facility at NIST. The measurement technique employed noncontact video microscopy using high-accuracy translation stages. We have quantified the differences between the participating institutions' aperture area measurements and find no evidence to support the hypothesis that preflight aperture area measurements were the root cause of discrepancies in long-term total solar irradiance satellite measurements. Another result is the assessment of uncertainties assigned to methods used by participants. We find that uncertainties assigned to a participant's values may be underestimated.

  17. Pressure sounding of the middle atmosphere from ATMOS solar occultation measurements of atmospheric CO(2) absorption lines.

    PubMed

    Abrams, M C; Gunson, M R; Lowes, L L; Rinsland, C P; Zander, R

    1996-06-01

    A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier-transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(2) lines with temperature-insensitive strengths by measuring the slant-column CO(2) amount and by adjusting the viewing geometry until the calculated column matches the observed column. Tangent pressures are determined with a spectroscopic precision of l%-3%, corresponding to a tangent-point height precision of 70-210 m. The total uncertainty is limited primarily by the quality of the spectra and ranges between 4% and 6% (280-420 m) for spectra with signal-to-noise ratios of 300:1 and between 4% and 10% for spectra with signal-to-noise ratios of 100:1. The retrieval of atmospheric pressure increases the accuracy of the retrieved-gas concentrations by minimizing the effect of systematic errors introduced by climatological pressure data, ephemeris parameters, and the uncertainties in instrumental pointing.

  18. Theoretical simulation of solar spectra in the middle ultraviolet and visible for atmospheric trace constituent measurements

    NASA Technical Reports Server (NTRS)

    Goldman, A.

    1979-01-01

    The data compiled during the study allowed a detailed examination of the attenuation of the solar radiance by the combined effect of the atmospheric trace gases and the SAGE filters. The case of the 0.44 microns channel is presented. The amounts of NO2, NO2, O3 and the airmass were chosen to closely simulate a low sun spectral scan from a 9 February 1977 balloon flight. The solar radiance outside the earth's atmosphere was determined from the AFGL Sacramento Peak Observatory spectral data tape degraded to 2.0A resolution and normalized to Thekaekara's absolute intensities. The spectral absorption coefficients used for NO2 and O3 were tabulated previously.

  19. A search for short-term meteorological effects of solar variability in an atmospheric circulation model

    NASA Technical Reports Server (NTRS)

    Somerville, R. C. J.; Quirk, W. J.; Hansen, J. E.; Lacis, A. A.; Stone, P. H.

    1976-01-01

    A set of numerical experiments is carried out to test the short-range sensitivity of the Goddard Institute for Space Studies global atmospheric general-circulation model to changes in solar constant and ozone amount. These experiments consist of forecasts initiated with actual atmospheric data. One set of forecasts is made with a standard version of the model; another set uses the model modified by very different values of the solar constant (two-thirds and three-halves of the standard value) and of the ozone amount (zero and twice the standard amount). Twelve-day integrations with these very large variations show such small effects that the effects of realistic variations would almost certainly be insignificant meteorologically on this time scale.

  20. Solar wind and high energy particle effects in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Lastovicka, Jan

    1989-01-01

    The solar wind variability and high energy particle effects in the neutral middle atmosphere are not much known. These factors are important in the high latitude upper mesosphere, lower thermosphere energy budget. They influence temperature, composition (minor constituents of nitric oxide, ozone), circulation (wind system) and airflow. The vertical and latitudinal structures of such effects, mechanisms of downward penetration of energy and questions of energy abundance are largely to be solved. The most important recent finding seems to be the discovery of the role of highly relativistic electrons in the middle atmosphere at L = 3 - 8 (Baker et al., 1987). The solar wind and high energy particle flux variability appear to form a part of the chain of possible Sun-weather (climate) relationships. The importance of such studies in the nineties is emphasized by their role in big international programs STEP and IGBP - Global Change.

  1. A search for short-term meteorological effects of solar variability in an atmospheric circulation model

    NASA Technical Reports Server (NTRS)

    Somerville, R. C. J.; Quirk, W. J.; Hansen, J. E.; Lacis, A. A.; Stone, P. H.

    1976-01-01

    A set of numerical experiments is carried out to test the short-range sensitivity of the Goddard Institute for Space Studies global atmospheric general-circulation model to changes in solar constant and ozone amount. These experiments consist of forecasts initiated with actual atmospheric data. One set of forecasts is made with a standard version of the model; another set uses the model modified by very different values of the solar constant (two-thirds and three-halves of the standard value) and of the ozone amount (zero and twice the standard amount). Twelve-day integrations with these very large variations show such small effects that the effects of realistic variations would almost certainly be insignificant meteorologically on this time scale.

  2. Global biomass burning. Atmospheric, climatic, and biospheric implications

    SciTech Connect

    Levine, J.S.

    1991-01-01

    Biomass burning is a significant source of atmospheric gases and, as such, may contribute to global climate changes. Biomass burning includes burning forests and savanna grasslands for land clearing, burning agricultural stubble and waste after harvesting, and burning biomass fuels. The chapters in this volume include the following topics: remote sensing of biomass burning from space;geographical distribution of burning; combustion products of burning in tropical, temperate and boreal ecosystems; burning as a global source of atmospheric gases and particulates; impacts of biomass burning gases and particulates on global climate; and the role of biomass burning on biodiversity and past global extinctions. A total of 1428 references are cited for the 63 chapters. Individual chapters are indexed separately for the data bases.

  3. Global biomass burning - Atmospheric, climatic, and biospheric implications

    NASA Technical Reports Server (NTRS)

    Levine, Joel S. (Editor)

    1991-01-01

    The present volume discusses the biomass burning (BMB) studies of the International Global Atmospheric Chemistry project, GEO satellite estimation of Amazonian BMB, remote sensing of BMB in West Africa with NOAA-AVHRR, an orbital view of the great Chinese fire of 1987, BMB's role in tropical rainforest reduction, CO and O3 measurements of BMB in the Amazon, effects of vegetation burning on the atmospheric chemistry of the Venezuelan savanna, an assessment of annually-burned biomass in Africa, and light hydrocarbon emissions from African savanna burnings. Also discussed are BMB in India, trace gas and particulate emissions from BMB in temperate ecosystems, ammonia and nitric acid emissions from wetlands and boreal forest fires, combustion emissions and satellite imagery of BMB, BMB in the perspective of the global carbon cycle, modeling trace-gas emissions from BMB, NO(x) emissions from BMB, and cloud-condensation nuclei from BMB.

  4. Global biomass burning - Atmospheric, climatic, and biospheric implications

    NASA Technical Reports Server (NTRS)

    Levine, Joel S. (Editor)

    1991-01-01

    The present volume discusses the biomass burning (BMB) studies of the International Global Atmospheric Chemistry project, GEO satellite estimation of Amazonian BMB, remote sensing of BMB in West Africa with NOAA-AVHRR, an orbital view of the great Chinese fire of 1987, BMB's role in tropical rainforest reduction, CO and O3 measurements of BMB in the Amazon, effects of vegetation burning on the atmospheric chemistry of the Venezuelan savanna, an assessment of annually-burned biomass in Africa, and light hydrocarbon emissions from African savanna burnings. Also discussed are BMB in India, trace gas and particulate emissions from BMB in temperate ecosystems, ammonia and nitric acid emissions from wetlands and boreal forest fires, combustion emissions and satellite imagery of BMB, BMB in the perspective of the global carbon cycle, modeling trace-gas emissions from BMB, NO(x) emissions from BMB, and cloud-condensation nuclei from BMB.

  5. Venus atmospheric circulation - Observations and implications of the thermal structure

    NASA Technical Reports Server (NTRS)

    Limaye, S. S.

    1985-01-01

    Thermal structure data obtained by Pioneer Venus (PV) were analyzed and used to make calculations concerning cyclostrophic circulation around Venus. These indicate a balanced zonal (east to west) circulation, with midlatitude jets of peak velocities in the 110-120 m/s range, located between 50 and 40 mb in each hemisphere of the planet near 45 deg latitude. The calculations indicate breakdown of the balance conditions near the upper and lower boundaries at low latitudes. A slight asymmetry in the balanced zonal circulation arises out of an asymmetry in the thermal field. The PV radio occultation data show evidence of a direct meridional circulation that may be important in sustaining the atmospheric circulation of Venus. The value of continuous radio occultation measurements is stressed for studying shortand long-term variations of the atmospheric circulation.

  6. Understanding atmospheric peroxyformic acid chemistry: observation, modeling and implication

    NASA Astrophysics Data System (ADS)

    Liang, H.; Chen, Z. M.; Huang, D.; Wu, Q. Q.; Huang, L. B.

    2015-01-01

    The existence and importance of peroxyformic acid (PFA) in the atmosphere has been under controversy. We present here, for the first time, the observation data for PFA from four field measurements carried out in China. These data provided powerful evidence that PFA can stay in the atmosphere, typically in dozens of pptv level. The relationship between PFA and other detected peroxides was examined. The results showed that PFA had a strong positive correlation with its homolog, peroxyacetic acid, due to their similar sources and sinks. Through an evaluation of PFA production and removal rates, we proposed that the reactions between peroxyformyl radical (HC(O)O2) and formaldehyde or the hydroperoxyl radical (HO2) were likely to be the major source and degradation into formic acid (FA) was likely to be the major sink for PFA. Based on a box model evaluation, we proposed that the HC(O)O2 and PFA chemistry was a major source for FA under low NOx conditions. Furthermore, it is found that the impact of the HC(O)O2 and PFA chemistry on radical cycling was dependent on the yield of HC(O)O2 radical from HC(O) + O2 reaction. When this yield exceeded 50%, the HC(O)O2 and PFA chemistry should not be neglected for calculating the radical budget. To make clear the exact importance of HC(O)O2 and PFA chemistry in the atmosphere, further kinetic, field and modeling studies are required.

  7. Modeling of the middle atmosphere response to 27-day solar irradiance variability

    NASA Astrophysics Data System (ADS)

    Sukhodolov, Timofei; Rozanov, Eugene; Ball, William T.; Peter, Thomas; Schmutz, Werner

    2017-01-01

    The solar rotational variability (27-day) signal in the Earth's middle atmosphere has been studied for several decades, as it was believed to help in the understanding of the Sun's influence on climate at longer timescales. However, all previous studies have found that this signal is very uncertain, likely due to the influence of the internal variability of the atmosphere. Here, we applied an ensemble modeling approach in order to decrease internal random variations in the modeled time series. Using a chemistry-climate model (CCM), SOCOLv3, we performed two 30-member 3-year long (2003-2005) ensemble runs: with and without a rotational component in input irradiance fluxes. We also performed similar simulations with a 1-D model, in order to demonstrate the system behavior in the absence of any dynamical feedbacks and internal perturbations. For the first time we show a clear connection between the solar rotation and the stratospheric tropical temperature time-series. We show tropical temperature and ozone signal phase lag patterns that are in agreement with those from a 1-D model. Pronounced correlation and signal phase lag patterns allow us to properly estimate ozone and temperature sensitivities to irradiance changes. While ozone sensitivity is found to be in agreement with recent sensitivities reported for the 11-year cycle, temperature sensitivity appears to be at the lowest boundary of previously reported values. Analysis of temperature reanalysis data, separate ensemble members, and modeling results without a rotational component reveals that the atmosphere can produce random internal variations with periods close to 27 days even without solar rotational forcing. These variations are likely related to tropospheric wave-forcing and complicate the extraction of the solar rotational signal from observational time-series of temperature and, to a lesser extent, of ozone. Possible ways of further improving solar rotational signal extraction are discussed.

  8. Atmospheric escape and solar wind precipitation - a comparison between Mars and Venus

    NASA Astrophysics Data System (ADS)

    Stenberg, Gabriella; Nilsson, Hans; Barabash, Stas; Holmström, Mats; Futaana, Yoshifumi

    Mars and Venus both have atmospheres but both lack a substantial intrinsic magnetic field. Hence, their interaction with the solar wind is similar. Due to currents set up in the ionospheres the interplanetary magnetic field embedded in the solar wind drapes around the planets forming induced magnetospheres. The plasma instrument packages ASPERA-3 and ASPERA-4 on the two spacecraft Mars Express and Venus Express are very similar and invite to a comparison between the two plasma environments. In this study we used the Ion Mass Analyser (IMA) on both spacecraft to investigate both the atmospheric escape (outflow) from the two planets and the solar wind precipitation onto the upper atmospheres (inflow). We focus on the differences between the two planets. We look at the average morphology of the outflow and find that on Venus the heavy ion escape in more confined inside the induced magnetosphere boundary (IMB) compared to Mars. Comparing the temperatures of the escaping planetary ions and we note that the colder population we see on Mars is absent on Venus. We continue by investigating the average flow directions of heavy ions and protons and conclude that in the tail there is a clear difference. On Venus ions move towards the tail center while they flow more in the anti-sunward direction on Mars. For the protons the situation is the opposite: On Venus they move mainly anti-sunward and on Mars towards the tail center. Studying the inflow we conclude that on Mars we regularly observe precipitating solar wind ions (H (+) and He (2+) ) inside the IMB, while on Venus no precipitating alpha-particles have been detected and only a few cases of solar wind proton precipitation.

  9. Effects of long-period solar activity fluctuation on temperature and pressure of the terrestrial atmosphere

    NASA Technical Reports Server (NTRS)

    Rubashev, B. M.

    1978-01-01

    The present state of research on the influence of solar sunspot activity on tropospheric temperature and pressure is reviewed. The existence of an 11-year temperature cycle of 5 different types is affirmed. A cyclic change in atmospheric pressure, deducing characteristic changes between 11-year cycles is discussed. The existence of 80-year and 5-to-6-year cycles of temperature is established, and physical causes for birth are suggested.

  10. Newtonian CAFE: a new ideal MHD code to study the solar atmosphere

    NASA Astrophysics Data System (ADS)

    González-Avilés, J. J.; Cruz-Osorio, A.; Lora-Clavijo, F. D.; Guzmán, F. S.

    2015-12-01

    We present a new code designed to solve the equations of classical ideal magnetohydrodynamics (MHD) in three dimensions, submitted to a constant gravitational field. The purpose of the code centres on the analysis of solar phenomena within the photosphere-corona region. We present 1D and 2D standard tests to demonstrate the quality of the numerical results obtained with our code. As solar tests we present the transverse oscillations of Alfvénic pulses in coronal loops using a 2.5D model, and as 3D tests we present the propagation of impulsively generated MHD-gravity waves and vortices in the solar atmosphere. The code is based on high-resolution shock-capturing methods, uses the Harten-Lax-van Leer-Einfeldt (HLLE) flux formula combined with Minmod, MC, and WENO5 reconstructors. The divergence free magnetic field constraint is controlled using the Flux Constrained Transport method.

  11. Models of the quiet and active solar atmosphere from Harvard OSO data.

    NASA Technical Reports Server (NTRS)

    Noyes, R. W.

    1971-01-01

    Review of some Harvard Observatory programs aimed at defining the physical conditions in quiet and active solar regions on the basis of data obtained from the OSO-IV and OSO-VI spacecraft. The spectral range covered is from 300 A to 1400 A. This spectral range consists of emission lines and continua from abundant elements such as hydrogen, helium, carbon, nitrogen, oxygen, silicon, magnesium, aluminum, neon, iron, and calcium in various ionization states ranging from neutral to 15 times ionized. The structure is discussed of the quiet solar atmosphere as deduced from center-to-limb behavior of spectral lines and continua formed in the chromosphere and corona. In reviewing investigations of solar active regions, it is shown that the structure of these regions varies in a complicated manner from point to point. The local structure is influenced by factors such as the magnetic field configuration within the active region and the age or evolutionary state of the region.

  12. Dynamics of the solar atmosphere. VI. Resonant oscillations of an atmospheric cavity: observations.

    NASA Astrophysics Data System (ADS)

    Deubner, F.-L.; Waldschik, T.; Steffens, S.

    1996-03-01

    We have evaluated new, spatially one- and two-dimensional time series of photospheric and chromospheric Fraunhofer lines at a large number of positions in the line profile, with the 'lambdameter' method. As a result we have obtained the velocity and brightness fluctuations corresponding to many closely staggered height levels in the atmosphere, and their respective phase spectra as a diagnostic of the wave fields involved. This material has not only served to define more accurately and specifically the character of the 180deg phase jump observed before in V-I spectra of the NaD_2_ line in internetwork regions, and to reveal the narrow height interval that gives rise to this discontinuity in the phase spectra. We have also discovered another discontinuity in V-V spectra of the same Fraunhofer line at nearly the same frequency (7.0mHz). Since neither running nor standing waves alone can explain the observed solitary phase discontinuities, our results provide strong evidence in favour of an atmosphere that supports (at least, and probably more than) one eigenmode as a component of the wave field.

  13. Theoretical simulation of solar spectra in the middle ultraviolet and visible for atmospheric trace constituent measurements

    NASA Technical Reports Server (NTRS)

    Goldman, A.

    1978-01-01

    Two balloon flights reaching float altitudes of approximately 30 and 40 km respectively, were used to obtain scans of the ultraviolet and visible solar spectra. Both flights covered the UV (2800-3500A) at approximately 0.3A resolution and the visible at approximately 0.6A. Numerous scans were obtained during ascent and from float for both flights. All spectral scans obtained at float, from high sun to low sun, were calibrated in wavelength by using several standard solar spectra for line position references. Comparisons of low sun scans and high sun scans show significant atmospheric continuum extinction and have the potential of being used to identify atmospheric lines superimposed on the attenuated solar spectrum. The resolution was mathematically degraded to approximately 5A to better see the broad band atmospheric extinction. This low resolution is also appropriate for the available low resolution absorption coefficients of NO2 and O3, allowing the identification of NO2 and O3 features on the sunset spectra.

  14. Importance of Reducing Vapor Atmosphere in the Fabrication of Tin-Based Perovskite Solar Cells.

    PubMed

    Song, Tze-Bin; Yokoyama, Takamichi; Stoumpos, Constantinos C; Logsdon, Jenna; Cao, Duyen H; Wasielewski, Michael R; Aramaki, Shinji; Kanatzidis, Mercouri G

    2017-01-18

    Tin-based halide perovskite materials have been successfully employed in lead-free perovskite solar cells, but the tendency of these materials to form leakage pathways from p-type defect states, mainly Sn(4+) and Sn vacancies, causes poor device reproducibility and limits the overall power conversion efficiencies (PCEs). Here, we present an effective process that involves a reducing vapor atmosphere during the preparation of Sn-based halide perovskite solar cells to solve this problem, using MASnI3, CsSnI3, and CsSnBr3 as the representative absorbers. This process enables the fabrication of remarkably improved solar cells with PCEs of 3.89%, 1.83%, and 3.04% for MASnI3, CsSnI3, and CsSnBr3, respectively. The reducing vapor atmosphere process results in more than 20% reduction of Sn(4+)/Sn(2+) ratios, which leads to greatly suppressed carrier recombination, to a level comparable to their lead-based counterparts. These results mark an important step toward a deeper understanding of the intrinsic Sn-based halide perovskite materials, paving the way to the realization of low-cost and lead-free Sn-based halide perovskite solar cells.

  15. Atmospheric Electrification in Dusty, Reactive Gases in the Solar System and Beyond

    NASA Astrophysics Data System (ADS)

    Helling, Christiane; Harrison, R. Giles; Honary, Farideh; Diver, Declan A.; Aplin, Karen; Dobbs-Dixon, Ian; Ebert, Ute; Inutsuka, Shu-ichiro; Gordillo-Vazquez, Francisco J.; Littlefair, Stuart

    2016-07-01

    Detailed observations of the solar system planets reveal a wide variety of local atmospheric conditions. Astronomical observations have revealed a variety of extrasolar planets none of which resembles any of the solar system planets in full. Instead, the most massive amongst the extrasolar planets, the gas giants, appear very similar to the class of (young) brown dwarfs which are amongst the oldest objects in the Universe. Despite this diversity, solar system planets, extrasolar planets and brown dwarfs have broadly similar global temperatures between 300 and 2500 K. In consequence, clouds of different chemical species form in their atmospheres. While the details of these clouds differ, the fundamental physical processes are the same. Further to this, all these objects were observed to produce radio and X-ray emissions. While both kinds of radiation are well studied on Earth and to a lesser extent on the solar system planets, the occurrence of emissions that potentially originate from accelerated electrons on brown dwarfs, extrasolar planets and protoplanetary disks is not well understood yet. This paper offers an interdisciplinary view on electrification processes and their feedback on their hosting environment in meteorology, volcanology, planetology and research on extrasolar planets and planet formation.

  16. A construction kit for atmospheric activity of cool stars based on solar characteristics

    NASA Astrophysics Data System (ADS)

    Schrijver, C. J.

    2000-05-01

    Stars other than the Sun can, at present, be studied only as point sources. The Sun, in contrast, can be studied in great detail, but it shows us the magnetic workings of only a single star. This talk presents numerical simulations of model stars of widely different levels of magnetic activity, based on the solar recipes for emergence, dispersal, and disappearance of magnetic field. These simulations are used to simulated stellar observations. The Sun is found to be typical of its class: the solar properties are compatible with the disk-integrated properties of other stars with convective envelopes that exhibit magnetic activity. This conclusion requires three new processes to be included in a long-familiar description of the surface field: the emergence and evolution of small and ephemeral regions, the collision and fragmentation of concentrations of flux, and the magnetoconvective coupling that slows the motion of large concentrations. The model allows us to draw conclusions on ephemeral-region populations in other stars, on rotation-activity relationships, and on radiative losses from the outer atmospheres (from chromosphere to corona) of all cool stars: the solar-stellar connection is a strong component of our quest to understand what makes the Sun tick. With this model, the solar/stellar outer atmosphere can be modeled in a laboratory setting, in which the experimenter has control over all parameters.

  17. Implications of isotopic compositions of N and Ne in the Martian atmosphere to temporal evolution of its atmosphere and regolith

    NASA Technical Reports Server (NTRS)

    Lal, D.

    1992-01-01

    The isotopic compositions of N and Ne in the Martian atmosphere are governed by several factors, principal among which are the temporal evolution in (1) the absolute surface pressure of oxygen, (2) the physicochemical characteristics of the regolith, and finally (3) the N-15 enrichment expected due to preferential hydrodynamical escape of N-14 (due to solar wind bombardment). Each of these factors is unique to Mars. In fact, no other planet offers the uniquely favorable situations for N-15 and Ne-21 enrichments. The cosmogenic production of N-15 is, in particular, unique. It promises to provide very valuable constraints on the temporal evolution of the martian CO2 and H2O, both in the atmosphere and regolith. The rate of production of cosmogenic (spallation) N-15 is dependent on the surface pressure of oxygen, the principal target element for formation of N-15. In view of the relatively high O/N ratio in the martian atmosphere, relatively high N-15/N ratio are expected to arise from cosmogenic reactions. The added bonus comes from the fact that an appreciable production of N-15 is expected in the martian regolith because of its thin atmosphere. From model calculations it is shown that if accurate isotopic composition data become available for N and Ne, it should be possible to put robust constraints on the time averages martian oxygen surface pressure and subsurface water in the upper layers.

  18. Radiative Transfer Model in the Atmosphere and Experimental Solar Data of Yaounde Location

    NASA Astrophysics Data System (ADS)

    Dountio, E. G.; Njomo, D.; Fouda, E.; Simo, A.

    2006-11-01

    The Sun is the primary source of energy supplying the Earth. This energy absorbed by the various components of the atmosphere, the oceans, the vegetation and Earth’s surface, is at the origin of the forces that control the climatic changes, the general circulation of the atmosphere, the temperature of the atmosphere and that of the oceans and the ionization of atmospheric gases, etc. The solar energy received on Earth’s surface is also directly used in technological applications such as solar heaters, solar dryers and other solar distillers, and the photovoltaic generators, etc. The calculation of the thermal performances of these apparatuses can be well made only if the spectral and even angular distribution of the solar irradiation arriving on the ground surface is well known. Moreover, the well known characteristics of the solar radiation arriving on the ground could inform us about the atmospheric phenomena that influenced its transfer, and consequently provide a better correction of the sensors response while receiving a signal from outer space in its direction, or the correction to be made on the response of a sensor while receiving data from a terrestrial sender. Only a few measurement stations of solar radiation are currently running and are not well managed, particularly in developing countries where the maintenance of a park of pyranometers on the ground is difficult and expensive. Moreover, where these measurements exist, they are rarely carried out for various wavelengths and/or angles. Such data are on the other hand accessible by numerical calculation, by solving the radiative transfer equation (ETR) in the atmosphere. One of the major factors attenuating the solar radiation received on the ground is scattering by clouds. The non- homogeneous nature of the clouds justifies the difficulty shown by the researchers to insert realistic profiles of clouds in radiative transfer models in a parallel stratified atmosphere [1, 2]. Several recent studies

  19. Nightglow in the upper atmosphere of Mars and implications for atmospheric transport.

    PubMed

    Bertaux, Jean-Loup; Leblanc, François; Perrier, Séverine; Quemerais, E; Korablev, Oleg; Dimarellis, E; Reberac, A; Forget, F; Simon, P C; Stern, S A; Sandel, Bill

    2005-01-28

    We detected light emissions in the nightside martian atmosphere with the SPICAM (spectroscopy for the investigation of the characteristics of the atmosphere of Mars) ultraviolet (UV) spectrometer on board the Mars Express. The UV spectrum of this nightglow is composed of hydrogen Lyman alpha emission (121.6 nanometers) and the gamma and delta bands of nitric oxide (NO) (190 to 270 nanometers) produced when N and O atoms combine to produce the NO molecule. N and O atoms are produced by extreme UV photodissociation of O2, CO2, and N2 in the dayside upper atmosphere and transported to the night side. The NO emission is brightest in the winter south polar night because of continuous downward transport of air in this region at night during winter and because of freezing at ground level.

  20. Impact of Atmospheric Attenuations Time Resolutions in Solar Radiation Derived from Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Cony, Marco; Liria, Juan; Weisenberg, Ralf; Serrano, Enrique

    2014-05-01

    Accurate knowledge of solar irradiance components at the earth surface is of highly interest in many scientific and technology branches concerning meteorology, climate, agriculture and solar energy applications. In the specific case of solar energy systems the solar resource analysis with accuracy is a first step in every project since it is a required data for design, power output estimations, systems simulations and risk assessments. Solar radiation measurement availability is increasing both in spatial density and in historical archiving. However, it is still quite limited and most of the situations cannot make use of a long term ground database of high quality since solar irradiance is not generally measured where users need data. Satellite-derived solar radiation estimations are a powerful and valuable tool for solar resource assessment studies that have achieved a relatively high maturity due to years of developments and improvements. However, several sources of uncertainty are still present in satellite-derived methods. In particular, the strong influence of atmospheric attenuation information as input to the method is one of the main topics of improvement. Since solar radiation attenuation by atmospheric aerosols, and water vapor in a second place, is, after clouds, the second most important factor determining solar radiation, and particularly direct normal irradiance, the accurate knowledge of aerosol optical depth and water vapor content is relevant in the final output of satellite-derived methods. This present work, two different datasets we are used for extract atmospheric attenuation information. On the one hand the monthly mean values of the Linke turbidity factor from Meteotest database, which are twelve unique values of the Linke turbidity worldwide with a spatial resolution of 1/12º. On the other hand, daily values of AOD (Aerosol Optical Depth) at 550 nm, Angstrom alpha exponent and water vapor column were taken from a gridded database that

  1. Monte Carlo study of interaction between solar wind plasma and Venusian upper atmosphere

    NASA Astrophysics Data System (ADS)

    Shematovich, V. I.; Bisikalo, D. V.; Barabash, S.; Stenberg, G.

    2014-09-01

    Isolated events of proton and alpha particle precipitation in the Venusian atmosphere were recorded with the use of the ASPERA-4 analyzer on board the ESA Venus Express spacecraft. Using a Monte Carlo simulation method for calculation of proton and alpha particle precipitations in the Venusian atmosphere, reflected and upward directed particle fluxes have been found. It has been found that only a vanishing percentage of protons and alpha particles are backscattered to the Venusian exosphere when neglecting the induced magnetic field and under conditions of low solar activity. Accounting for the induced field drastically changes the situation: the backscattered by the atmosphere energy fluxes increase up to 44% for the horizontal magnetic field B = 20 nT, measured for Venus, for the case of precipitating protons, and up to 64%, for alpha particles. The reflected energy fluxes increase to about 100% for both protons and alpha particles as the field grows to 40 nT, i.e., the atmosphere is protected against penetration of solar wind particles.

  2. Neutral Middle Atmospheric Influences by the Extremely Large October 2003 Solar Proton

    NASA Technical Reports Server (NTRS)

    Jackman, C. H.; Fleming, E. L.

    2004-01-01

    The huge coronal mass ejection (CME) on October 28, 2003 caused an extremely large solar proton event (SPE) 3t the Earth, which impacted the middle atmospheric polar cap regions. The highly energetic protons produce ionizations, excitations, dissociations, and dissociative ionizations of the background constituents, which lead to the production of HO(x) (H, OH, HO2) and NO(y) (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2). The total production of middle atmospheric NO(y) molecules by individual SPEs can be used to compare their sizes. Using this scale, the extremely large October 2003 SPE was the fourth largest in the past 40 years and the second largest of solar cycle 23. Only the October 1989, August 1972, and July 2000 SPEs were larger. The Goddard Space Flight Center (CSFC) Two-dimensional (2D)) Model was used in computing the influence of this gigantic SPE The NO(y) amount was increased by over two orders of Atmosphere Research Satellite (UARS) Halogen Occultation Experiment (HALOE) measurements as a result of this noteworthy SPE. The model also calculated polar middle mesosphere ozone decreases of over 70% during the SPE. Other atmospheric impacts from both model predictions and measurements as a result of this major SPE will be discussed in this paper.

  3. Neutral Middle Atmospheric Influences by the Extremely Large October 2003 Solar Proton Event

    NASA Technical Reports Server (NTRS)

    Jackman, C. H.; Fleming, E. L.

    2004-01-01

    The huge coronal mass ejection (CME) on October 28,2003 caused an extremely large solar proton event (SPE) at the Earth, which impacted the middle atmospheric polar cap regions. The highly energetic protons produce ionizations, excitations, dissociations, and dissociative ionizations of the background constituents, which lead to the production of HOx (H, OH, HO2) and NOy (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2). The total production of middle atmospheric NOy molecules by individual SPEs can be used to compare their sizes. Using this scale, the extremely large October 2003 SPE was the fourth largest in the past 40 years and the second largest of solar cycle 23. Only the October 1989, August 1972, and July 2000 SPEs were larger. The Goddard Space Flight Center (GSFC) Two-dimensional (2D) Model was used in computing the influence of this gigantic SPE. The NOy amount was increased by over two orders of magnitude in the mesosphere in both the GSFC 2D Model computations and Upper Atmosphere Research Satellite (UARS) Halogen Occultation Experiment (HALOE) measurements as a result of this noteworthy SPE. The model also calculated polar middle mesospheric ozone decreases of over 70% during the SPE. Other atmospheric impacts from both model predictions and measurements as a result of this major SPE will be discussed in this paper.

  4. TITAN’S UPPER ATMOSPHERE FROM CASSINI/UVIS SOLAR OCCULTATIONS

    SciTech Connect

    Capalbo, Fernando J.; Bénilan, Yves; Yelle, Roger V.; Koskinen, Tommi T.

    2015-12-01

    Titan’s atmosphere is composed mainly of molecular nitrogen, methane being the principal trace gas. From the analysis of 8 solar occultations measured by the Extreme Ultraviolet channel of the Ultraviolet Imaging Spectrograph (UVIS) on board Cassini, we derived vertical profiles of N{sub 2} in the range 1100–1600 km and vertical profiles of CH{sub 4} in the range 850–1300 km. The correction of instrument effects and observational effects applied to the data are described. We present CH{sub 4} mole fractions, and average temperatures for the upper atmosphere obtained from the N{sub 2} profiles. The occultations correspond to different times and locations, and an analysis of variability of density and temperature is presented. The temperatures were analyzed as a function of geographical and temporal variables, without finding a clear correlation with any of them, although a trend of decreasing temperature toward the north pole was observed. The globally averaged temperature obtained is (150 ± 1) K. We compared our results from solar occultations with those derived from other UVIS observations, as well as studies performed with other instruments. The observational data we present confirm the atmospheric variability previously observed, add new information to the global picture of Titan’s upper atmosphere composition, variability, and dynamics, and provide new constraints to photochemical models.

  5. Implications of ``peak oil'' for atmospheric CO2 and climate

    NASA Astrophysics Data System (ADS)

    Kharecha, Pushker A.; Hansen, James E.

    2008-09-01

    Unconstrained CO2 emission from fossil fuel burning has been the dominant cause of observed anthropogenic global warming. The amounts of "proven" and potential fossil fuel reserves are uncertain and debated. Regardless of the true values, society has flexibility in the degree to which it chooses to exploit these reserves, especially unconventional fossil fuels and those located in extreme or pristine environments. If conventional oil production peaks within the next few decades, it may have a large effect on future atmospheric CO2 and climate change, depending upon subsequent energy choices. Assuming that proven oil and gas reserves do not greatly exceed estimates of the Energy Information Administration, and recent trends are toward lower estimates, we show that it is feasible to keep atmospheric CO2 from exceeding about 450 ppm by 2100, provided that emissions from coal, unconventional fossil fuels, and land use are constrained. Coal-fired power plants without sequestration must be phased out before midcentury to achieve this CO2 limit. It is also important to "stretch" conventional oil reserves via energy conservation and efficiency, thus averting strong pressures to extract liquid fuels from coal or unconventional fossil fuels while clean technologies are being developed for the era "beyond fossil fuels". We argue that a rising price on carbon emissions is needed to discourage conversion of the vast fossil resources into usable reserves, and to keep CO2 beneath the 450 ppm ceiling.

  6. The Martian paleo-magnetosphere during the early Naochian and its implication for the early Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Khodachenko, Maxim L.; Scherf, Manuel; Amerstorfer, Ute; Alexeev, Igor; Johnstone, Colin; Belenkaya, Elena; Tu, Lin; Lichtenegger, Herbert; Guedel, Manuel; Lammer, Helmut

    2016-10-01

    During the late 1990's the Mars Global Surveyor MAG/ER experiment detected crustal remanent magnetization at Mars indicating an ancient internal magnetic dynamo. The location of this remanent magnetization and in particular its absence at the large Martian impact craters like Hellas suggests a cessation of the dynamo during the early Naochian epoch, i.e. ~ 4.1 to 4 billion years ago. The strength of the remanent magnetization together with dynamo theory are indicating an ancient dipole field strength lying in the range of ~0.1 and ~1.0 of the present-day dipole field of the Earth, making the Martian paleo-magnetosphere comparable with the terrestrial paleo-magnetosphere. This also has implication for the early Martian atmosphere.In this poster we will present simulations of the paleo-magnetosphere of Mars for the early Naochian, just before cessation (i.e. for ~4.1 to ~4.0 billion years ago). These were performed with an adapted version of the Paraboloid Magnetospheric Model (PMM) of the Skobeltsyn Institute of Nuclear Physics of the Moscow State University, which serves as an ISO standard for the magnetosphere. Here the ancient magnetic field was assumed to be a dipole field (with dipole tilt ψ=0). The ancient solar wind ram pressure as important input parameter was derived from a newly developed solar/stellar wind evolution model, which is strongly dependent on the rotation rate of the early Sun. These simulations show that for the most extreme case of a fast rotating Sun and a paleomagnetic field strength of 0.1 of the present-day Earth value, the Martian magnetopause was located at ~5.5 RM (i.e. ~2.9 RE) above the Martian surface. Assuming a strong dipole field (i.e. 1.0 of present-day Earth) and a slow rotating Sun - our least extreme case - would lead to a standoff-distance of rs~16 RM (i.e. ~8.5 RE).Our simulations also have implications for the early Martian atmosphere, which will be demonstrated within this poster. These first results on the erosion of

  7. MSG-7: atmospheric penetration of solar radiation in the range of Schumann-Runge bands

    SciTech Connect

    Frederick, J.E.

    1982-12-01

    There have been major efforts in measuring extraterrestrial solar irradiance for use in atmospheric studies. The quantity of immediate relevance to theoretical studies is the number of photons which reach a given altitude in the middle atmosphere. Current models compute the attenuated radiation field but the cross sections available for the major absorbers, O2 and O3, often come from experiments that are now quite old. Balloon measurements show some significant differences between the predicted and observed ultraviolet radiation field between 30 and 40 km. The wavelength region to be studied includes Lyman alpha plus the range 175 nm to the visible. Specific topics to be addressed are as follows: (1) the cross sections of the major absorbers, O2 and O3 including the Schumann-Runge bands as a subset (2) comparison of the in situ measurements of the attenuated radiation field with calculations and (3) the relevance of the scattered and reflected radiation fields for middle atmospheric processes.

  8. MSG-7: Atmospheric Penetration of Solar Radiation in the Range of Schumann-runge Bands

    NASA Technical Reports Server (NTRS)

    Frederick, J. E.

    1982-01-01

    There have been major efforts in measuring extraterrestrial solar irradiance for use in atmospheric studies. The quantity of immediate relevance to theoretical studies is the number of photons which reach a given altitude in the middle atmosphere. Current models compute the attenuated radiation field but the cross sections available for the major absorbers, O2 and O3, often come from experiments that are now quite old. Balloon measurements show some significant differences between the predicted and observed ultraviolet radiation field between 30 and 40 km. The wavelength region to be studied includes Lyman alpha plus the range 175 nm to the visible. Specific topics to be addressed are as follows: (1) the cross sections of the major absorbers, O2 and O3 including the Schumann-Runge bands as a subset; (2) comparison of the in situ measurements of the attenuated radiation field with calculations; and (3) the relevance of the scattered and reflected radiation fields for middle atmospheric processes.

  9. Atmospheric solar absorption measurements in the 9 to 11 mu m region using a diode laser heterodyne spectrometer

    NASA Technical Reports Server (NTRS)

    Harward, C. N.; Hoell, J. M., Jr.

    1980-01-01

    A tunable diode laser heterodyne radiometer was developed for ground-based measurements of atmospheric solar absorption spectra in the 8 to 12 microns spectral range. The performance and operating characteristics of this Tunable Infrared Heterodyne Radiometer (TIHR) are discussed along with atmospheric solar absorption spectra of HNO3, O3, CO2, and H2O in the 9 to 11 microns spectral region.

  10. Influence of geomagnetic activity and atmospheric pressure on human arterial pressure during the solar cycle 24

    NASA Astrophysics Data System (ADS)

    Azcárate, T.; Mendoza, B.; Levi, J. R.

    2016-11-01

    We performed a study of the systolic (SBP) and diastolic (DBP) arterial blood pressure behavior under natural variables such as the atmospheric pressure (AtmP) and the horizontal geomagnetic field component (H). We worked with a sample of 304 healthy normotense volunteers, 152 men and 152 women, with ages between 18 and 84 years in Mexico City during the period 2008-2014, corresponding to the minimum, ascending and maximum phases of the solar cycle 24. The data was divided by gender, age and day/night cycle. We studied the time series using three methods: Correlations, bivariate and superposed epochs (within a window of three days around the day of occurrence of a geomagnetic storm) analysis, between the SBP and DBP and the natural variables (AtmP and H). The correlation analysis indicated correlation between the SBP and DBP and AtmP and H, being the largest during the night. Furthermore, the correlation and bivariate analysis showed that the largest correlations are between the SBP and DBP and the AtmP. The superposed epoch analysis found that the largest number of significant SBP and DBP changes occurred for women. Finally, the blood pressure changes are larger during the solar minimum and ascending solar cycle phases than during the solar maximum; the storms of the minimum were more intense than those of the maximum and this could be the reason of behavior of the blood pressure changes along the solar cycle.

  11. A visible solar occultation of Titan's atmosphere from Cassini-VIMS

    NASA Astrophysics Data System (ADS)

    D'Aversa, Emiliano; Moriconi, Maria Luisa; Loison, Jean-Christophe; Dobrijevic, Michel; Oliva, Fabrizio; Sindoni, Giuseppe

    2017-04-01

    The VIMS (Visible and Infrared Mapping Spectrometer) instrument on board Cassini spacecraft was able to acquire several stellar and solar occultation measurements of Titan's atmosphere through the mission. VIMS is composed by two separate spectrometers (IR and V channels) covering wavelengths from 0.8 to 5.1 microns and from 0.35 to 1.05 micron respectively. Almost all the aforementioned occultation sequences involved the IR channel, keeping V channel off (see e.g. [1],[2]). In only one case VIMS-V acquired data during a Titan solar occultation and we will report here about the analysis of this data set. This sequence consists of 210 data cubes composed of 32 samples x 32 lines x 96 spectral bins, acquired through the solar entrance port of the VIS channel. The inbound phase of the occultation was registered, hence the Sun gradually disappears with time behind Titan's limb. Although the projected size of the Sun's disk is much smaller than the VIMS 0.5 mrad pixel, the solar signal during occultation is spread over the images mainly because of atmospheric scattering. Hence, a set of 96 occultation light curves, one for each of the 7 nm wide VIMS-V spectral bin, was obtained, by spatial integration over the full field of view. In the extracted light curves four phases can be clearly distinguished at nearly all wavelengths: 1) high constant level, 2) exponential drop, 3) short ledge at low level, 4) polynomial increase. These phases can be interpreted as 1) unocculted solar signal, 2) gas/haze extinction proportional to the atmosphere density, 3) extinction saturation due to thick aerosols layers, 4) solar forward and multiple scattering from dayside atmosphere becoming predominant. The phase 1) data allows estimating the unocculted solar signal average level and its fluctuations, useful to directly calculate the atmospheric transmission profiles. No radiometric calibration is needed in this process, reducing the uncertainties and biases related to it. Geometric

  12. Kelvin-Helmholtz Instability in the Solar Atmosphere, Solar Wind and Geomagnetosphere

    NASA Astrophysics Data System (ADS)

    Mishin, V. V.; Tomozov, V. M.

    2016-11-01

    Modern views on the nature of the Kelvin-Helmholtz (KH) instability and its manifestations in the solar corona, in the interplanetary medium, and at the geomagnetospheric boundary are under consideration. We briefly describe the main theoretical results of the KH instability obtained in the linear approximation. Analysis of observational data, confirming the occurrence of the KH instability in magnetic formations of the solar coronal plasma and on the daytime magnetopause, was mainly performed in the approximation of incompressibility. We show that the Rayleigh-Taylor instability can significantly enhance the KH instability in the above regions due to interface accelerations or its curvature. Special attention is focused on the compressibility effect on the supersonic shear flow instability in the solar wind (SW) and at the geomagnetic tail boundary where this instability is usually considered to be ineffective. We have shown that the phase velocity of oblique perturbations is substantially less than the flow velocity, and values of the growth rate and frequency range are considerably higher than when only taking velocity-aligned disturbances into account. We emphasize that the magnetic field and plasma density inhomogeneity which weaken the KH instability of subsonic shear flows, in the case of a supersonic velocity difference weaken the stabilizing effect of the medium compressibility, and can significantly increase the instability. Effective generation of oblique disturbances by the supersonic KH instability explains the observations of magnetosonic waves and the formation of diffuse shear flows in the SW and on the distant magnetotail boundary, as well as the SW-magnetosphere energy and impulse transfer.

  13. Atmosphere and water loss from early Mars under extreme solar wind and extreme ultraviolet conditions.

    PubMed

    Terada, Naoki; Kulikov, Yuri N; Lammer, Helmut; Lichtenegger, Herbert I M; Tanaka, Takashi; Shinagawa, Hiroyuki; Zhang, Tielong

    2009-01-01

    The upper limits of the ion pickup and cold ion outflow loss rates from the early martian atmosphere shortly after the Sun arrived at the Zero-Age-Main-Sequence (ZAMS) were investigated. We applied a comprehensive 3-D multi-species magnetohydrodynamic (MHD) model to an early martian CO(2)-rich atmosphere, which was assumed to have been exposed to a solar XUV [X-ray and extreme ultraviolet (EUV)] flux that was 100 times higher than today and a solar wind that was about 300 times denser. We also assumed the late onset of a planetary magnetic dynamo, so that Mars had no strong intrinsic magnetic field at that early period. We found that, due to such extreme solar wind-atmosphere interaction, a strong magnetic field of about approximately 4000 nT was induced in the entire dayside ionosphere, which could efficiently protect the upper atmosphere from sputtering loss. A planetary obstacle ( approximately ionopause) was formed at an altitude of about 1000 km above the surface due to the drag force and the mass loading by newly created ions in the highly extended upper atmosphere. We obtained an O(+) loss rate by the ion pickup process, which takes place above the ionopause, of about 1.5 x 10(28) ions/s during the first < or =150 million years, which is about 10(4) times greater than today and corresponds to a water loss equivalent to a global martian ocean with a depth of approximately 8 m. Consequently, even if the magnetic protection due to the expected early martian magnetic dynamo is neglected, ion pickup and sputtering were most likely not the dominant loss processes for the planet's initial atmosphere and water inventory. However, it appears that the cold ion outflow into the martian tail, due to the transfer of momentum from the solar wind to the ionospheric plasma, could have removed a global ocean with a depth of 10-70 m during the first < or =150 million years after the Sun arrived at the ZAMS.

  14. Simplified Solar Modulation Model of Inner Trapped Belt Proton Flux As a Function of Atmospheric Density

    NASA Technical Reports Server (NTRS)

    Wilson, Thomas L.; Lodhi, M. A. K.; Diaz, Abel B.

    2005-01-01

    No simple algorithm seems to exist for calculating proton fluxes and lifetimes in the Earth's inner, trapped radiation belt throughout the solar cycle. Most models of the inner trapped belt in use depend upon AP8 which only describes the radiation environment at solar maximum and solar minimum in Cycle 20. One exception is NOAAPRO which incorporates flight data from the TIROS/NOAA polar orbiting spacecraft. The present study discloses yet another, simple formulation for approximating proton fluxes at any time in a given solar cycle, in particular between solar maximum and solar minimum. It is derived from AP8 using a regression algorithm technique from nuclear physics. From flux and its time integral fluence, one can then approximate dose rate and its time integral dose. It has already been published in this journal that the absorbed dose rate, D, in the trapped belts exhibits a power law relationship, D = A(rho)(sup -n), where A is a constant, rho is the atmospheric density, and the index n is weakly dependent upon shielding. However, that method does not work for flux and fluence. Instead, we extend this idea by showing that the power law approximation for flux J is actually bivariant in energy E as well as density rho. The resulting relation is J(E,rho)approx.(sum of)A(E(sup n))rho(sup -n), with A itself a power law in E. This provides another method for calculating approximate proton flux and lifetime at any time in the solar cycle. These in turn can be used to predict the associated dose and dose rate.

  15. Nonlinear Spatial-Temporal Spectral Analyses for Diagnosing Solar 11-Year Signal in the Northern Hemisphere Atmosphere

    NASA Astrophysics Data System (ADS)

    Powell, A. M.; Chen, M.

    2005-12-01

    The major dilemma in the search for a Sun-Earth connection is tiny solar output variations appear insignificant relative to dynamic atmospheric changes while many synoptic and climatic parameters are found to be significantly correlated with the solar variation at different time scales. Based on previous analysis, the solar variations are assumed to exert their influence through nonlinear modulation of the existing dynamic or thermodynamic processes. Nonlinear spatial-temporal spectral analysis is helpful for identifying nonlinear solar signals in the atmospheric observations and establishing nonlinear feedback mechanisms. Using the 50-year NCEP/NCAR reanalysis data, an extensive spatial-temp spectral analysis is performed. Fourier transformation is first applied latitude by latitude to get zonal waves of different spatial scales. The time series of the amplitude (energy) of each wave is filtered to isolate different time-scale waves. From the viewpoint of linear wave theory, these waves are assumed to carry atmospheric energy derived from the original sources and the atmospheric response to the source functions. The temporal change of wave amplitude is closely related to the source energy change, such as boundary condition change, or nonlinear adjustment of background state (energy exchange from different scales), etc. The relevant spatial-temp spectral structure change associated with solar variations will be addressed in this study. The results suggest nonlinear atmospheric processes may couple solar variation with atmospheric variations.

  16. Global biomass burning - Atmospheric, climatic, and biospheric implications

    SciTech Connect

    Levine, J.S. )

    1990-09-01

    Topics discussed at the March 1990 American Geophysical Union's Conference on biomass burning which was attended by more than 175 participants representing 19 countries are presented. Conference highlights include discussion of remote sensing data concerning biomass burning (BB), gaseous and particle emissions resulting from BB in the tropics, BB in temperate and boreal ecosystems, the historic and prehistoric perspectives on BB, BB and global budgets for carbon, nitrogen, and oxygen, and the BB and the greenhouse effect. Global estimates of annual amounts of biomass burning and of the resulting release of carbon to the atmosphere and the mean gaseous emission ratios for fires in wetlands, chaparral, and boreal ecosystems are given. An overview is presented of some conference discussions including global burning from 1850-1980, the global impact of biomass burning, the great Chinese/Soviet fire of 1987, and burning and biogenic emissions.

  17. Atmospheric solar absorption measurements in the 9-11 micron region using a diode laser heterodyne spectrometer

    NASA Technical Reports Server (NTRS)

    Harward, C. N.; Hoell, J. M., Jr.

    1980-01-01

    A tunable diode laser heterodyne radiometer was developed for ground based measurements of atmospheric solar absorption spectra in the 9 to 12 micron spectral range. The performance and operating characteristics of this tunable infrared heterodyne radiometer (TIHR) is discussed along with recently measured heterodyne solar absorption spectra in the 10 to 11 micron spectral region.

  18. Implications of 'Peak Oil' for Atmospheric CO2 and Climate

    NASA Astrophysics Data System (ADS)

    Kharecha, P. A.; Hansen, J. E.

    2008-12-01

    Unconstrained CO2 emission from fossil fuel burning has been the dominant cause of observed anthropogenic global warming. The amounts of "proven" and potential fossil fuel reserves are uncertain and debated. Regardless of the true values, society has flexibility in the degree to which it chooses to exploit these reserves, especially unconventional fossil fuels and those located in extreme or pristine environments. If conventional oil production peaks within the next few decades, it may have a large effect on future atmospheric CO2 and climate change, depending upon subsequent energy choices. Assuming that proven oil and gas reserves do not greatly exceed estimates of the Energy Information Administration -- and recent trends are toward lower estimates -- we show that it is feasible to keep atmospheric CO2 from exceeding about 450 ppm by 2100, provided that emissions from coal, unconventional fossil fuels, and land use are constrained. Coal-fired facilities without sequestration must be phased out before midcentury to achieve this CO2 limit. It is also important to "stretch" conventional oil reserves via energy conservation and efficiency, thus averting strong pressures to extract liquid fuels from coal or unconventional fossil fuels while clean technologies are being developed for the era "beyond fossil fuels". We argue that a rising price on carbon emissions is needed to discourage conversion of the vast fossil resources into usable reserves, and to keep CO2 below 450 ppm. It is also plausible that CO2 can be returned below 350 ppm by 2100 or sooner, if more aggressive mitigation measures are enacted, most notably a phase-out of global coal emissions by circa 2030 and large- scale reforestation, primarily in the tropics but also in temperate regions.

  19. Validation of the Earth atmosphere models using the EUV solar occultation data from the CORONAS and PROBA 2 instruments

    NASA Astrophysics Data System (ADS)

    Slemzin, Vladimir; Kuzin, Sergey; Berghmans, David; Pertsov, Andrey; Dominique, Marie; Ulyanov, Artyom; Gaikovich, Konstantin

    Absorption in the atmosphere below 500 km results in attenuation of the solar EUV flux, variation of its spectra and distortion of solar images acquired by solar EUV instruments operating on LEO satellites even on solar synchronous orbits. Occultation measurements are important for planning of solar observations from these satellites, and can be used for monitoring the upper atmosphere as well as for studying its response to the solar activity. We present the results of the occultation measurements of the solar EUV radiation obtained by the CORONAS-F/SPIRIT telescope at high solar activity (2002), by the CORONAS-Photon/TESIS telescope at low activity (2009), and by the SWAP telescope and LYRA radiometer onboard the PROBA 2 satellite at moderate activity (2010). The measured attenuation profiles and the retrieved linear extinction coefficients at the heights 200-500 km are compared with simulations by the NRLMSIS-00 and DTM2013 atmospheric models. It was shown that the results of simulations by the DTM2013 model are well agreed with the data of measurements at all stages of solar activity and in presence of the geomagnetic storm, whereas the results of the NRLMSISE-00 model significantly diverge from the measurements, in particular, at high and low activity. The research leading to these results has received funding from the European Union’s Seventh Programme for Research, Technological Development and Demonstration under Grant Agreement “eHeroes” (project № 284461, www.eheroes.eu).

  20. Deriving the instrument transfer function from OMI solar observations and its implications for trace gas retrievals

    NASA Astrophysics Data System (ADS)

    Sun, K.; Liu, X.; Gonzalez Abad, G.; Cai, Z.; Yang, K.; Chance, K.

    2016-12-01

    The accurate characterization of instrument transfer function (ITF) is essential for the spectral calibration of space-borne grating spectrometers and the retrieval of the Earth's atmospheric constituents. For OMI, the ITF is complicated functions of both wavelength (the column dimension) and cross-track viewing direction (the row dimension). Preflight measurements, parameterized as hybrid Gaussian functions, have been used as static inputs in spectral calibration and trace gas retrievals. However, the launching process and the thermal/radiative contrast between the space and laboratory conditions may induce subtle changes in the ITF. The on-orbit thermal variation, instrument degradation, and switching of observation modes may also cause ITF variations. This study utilizes the frequent solar measurements from OMI and the recent development of high-resolution, high-accuracy reference solar spectrum to characterize the on-orbit behavior of the ITF. The ITF is fitted using various forms of analytical functions or variants of the preflight ITF. The cross-track dependence of OMI ITF is significantly different from the preflight measurements. The full width at half maximum (FWHM) of detector pixels at large viewing angles are up to 10% higher than the preflight ITF FWHM. Nonetheless, the OMI ITF is stable over time (more than 10 years of operation), despite of the decaying of detector SNR and the occurrence of OMI row anomaly. Impact of the updated ITF on the retrievals of trace gases (ozone, formaldehyde, etc.) will be discussed. These results have implications for future satellites targeting both short-lived species in the UV/visible and long-lived species in the infrared. The on-orbit behavior of ITF must be carefully investigated, especially for retrievals with high accuracy requirements.

  1. Solar wind flow about the terrestrial planets 2. Comparison with gas dynamic theory and implications for solar-planetary interactions

    SciTech Connect

    Slavin, J.A.; Holzer, R.E.; Spreiter, J.R.; Stahara, S.S.; Chaussee, D.S.

    1983-01-01

    This study utilizes gas dynamic calculations in conjunction with observational bow shock models to investigate the solar wind flow patterns about the terrestrial planets. Average dayside bow shock position could be predicted for the earth by theory with an error of only approx.2%, given the observed shape and location of the magnetopause. Accordingly, our findings confirm the validity of the single-fluid gas dynamic approximation for describing this major aspect of solar wind flow past the earth. Modeled using gas dynamic theory, the solar wind interactions with Venus and Mars exhibit very significant differences. At Mars the mean inferred altitude of the solar wind-obstacle interface varies from 510 km at the stagnation point to almost 1000 km near the terminator. The effective magnetic moment required to produce a magnetosphere of this size for average solar wind dynamic pressures and terrestrial-type internal current systems is 1.4 +- 0.6 x 10/sup 22/ G cm/sup 3/. Gas dynamic modeling of the January 21, 1972, Mars 3 and July 20, 1976, Viking 1 lander particles and fields observations supports the conclusion that the Martian obstacle to the solar wind lies at altitudes too high for it to be associated with only an ionospheric or atmospheric interaction. In contrast with Mars, our modeling of the Venus observations has found that the bow wave is closer to the planet than would be expected for a purely ionospheric obstacle. The subsolar width of the Venus ionosheath in the Venera and PVO measurements is only 60% and 90%, respectively, of that predicted by the gas dynamic model. This result is attributed to the presence of solar wind-neutral atmosphere interactions in the lower ionosheath that are not included in the gas dynamic code.

  2. Scatterers in Triton's atmosphere - Implications for the seasonal volatile cycle

    NASA Technical Reports Server (NTRS)

    Pollack, James B.; Schwartz, Joel M.; Rages, Kathy

    1990-01-01

    Nitrogen and methane ices on the surface of Triton, Neptune's largest satellite, are exchanged between the summer and winter hemispheres on a seasonal time scale. Images of the satellite's sky obtained by the Voyager 2 spacecraft show the presence of several types of scattering materials that provide insights into this seasonal cycle of volatiles. Discrete clouds, probably composed of N2 ice particles, arise in regions of active sublimation. They are found chiefly poloward of 30 deg S in the southern, summer hemisphere. Haze particles, probably made of hydrocarbon ices, are present above most, but not all places. Recent snowfall may have occurred at low southern latitudes in places where they are absent. The latent heat released in the formation of the discrete clouds may have a major impact on the thermal balance of the lower atmosphere. Triton may have been less red at the time of the Voyager flyby than 12 years earlier due to recent N2 snowfall at a wide range of latitudes.

  3. Martian supergene enrichment in Shalbatana Valley: Implications for Mars Early atmosphere

    NASA Astrophysics Data System (ADS)

    Popa, Ciprian; Carrozzo, Giacomo; DiAchille, Gaetano; Silvestro, Simone; Espostio, Francesca; Mennella, Vito

    2015-04-01

    The present work focuses on the detailed description of the first ever-identified supergene enrichment zone on Mars. The mineral paragenesis present at the site sets constrains on the characteristics of early Martian atmosphere. A chrysocolla/malachite bearing unit in the largest of Shalbatana Valley paleolacustrine sediment accumulation constitutes the proof for this process. The water permanence at the formation time is the main implication of this finding. Furthermore, the potential biogenic involvement at the mineralization stage adds scientific importance to the site. The latter implication could set the site as a high priority choice for future Martian in-situ robotic roving/sample-return missions. The relative age of the area (˜3.7 Ba) adds weight to this finding for purposes of planetary atmosphere evolution comparison. No Earth supergene deposit has survived that long, making this site extremely important to address the problem of the oxidative conditions of the primordial Earth and Mars atmospheres.

  4. A fast all-sky radiative transfer model and its implications for solar energy research

    NASA Astrophysics Data System (ADS)

    Xie, Y.; Sengupta, M.

    2015-12-01

    Radiative transfer models simulating broadband solar radiation, e.g. Rapid Radiation Transfer Model (RRTM) and its GCM applications, have been widely used by atmospheric scientists to model solar resource for various energy applications such as operational forecasting. Due to the complexity of solving the radiative transfer equation, simulating solar radiation under cloudy conditions can be extremely time consuming though many approximations, e.g. two-stream approach and delta-M truncation scheme, have been utilized. To provide a new option to approximate solar radiation, we developed a Fast All-sky Radiation Model for Solar applications (FARMS) using simulated cloud transmittance and reflectance from 16-stream RRTM model runs. The solar irradiances at the land surface were simulated by combining parameterized cloud properties with a fast clear-sky radiative transfer model. Using solar radiation measurements from the US Department of Energy's Atmospheric Radiation Measurement (ARM) central facility in Oklahoma as a benchmark against the model simulations, we were able to demonstrate that the accuracy of FARMS was comparable to the two-stream approach. However, FARMS is much more efficient since it does not explicitly solve the radiative transfer equation for each individual cloud condition. We further explored the use of FARMS to promote solar resource assessment and forecasting research through the increased ability to accommodate higher spatial and temporal resolution calculations for the next generation of satellite and numerical weather prediction (NWP) models.

  5. Impact of atmospheric species on copper indium gallium selenide solar cell stability: an overview

    NASA Astrophysics Data System (ADS)

    Theelen, Mirjam

    2016-01-01

    An overview of the measurement techniques and results of studies on the stability of copper indium gallium selenide (CIGS) solar cells and their individual layers in the presence of atmospheric species is presented: in these studies, Cu(In,Ga)Se2 solar cells, their molybdenum back contact, and their ZnO:Al front contact were exposed to liquid water purged with gases from the atmosphere, like carbon dioxide (CO2), oxygen (O2), nitrogen (N2), and air. The samples were analyzed before, during, and after exposure in order to define their stability under these conditions. The complete CIGS solar cells as well as the ZnO:Al front contact degraded rapidly when exposed to H2O combined with CO2, while they were relatively stable in H2O purged with O2 or N2. This was caused by either degradation of the grain boundaries in the ZnO:Al film or by the dissolution of part of this film. Uncovered molybdenum films, on the other hand, oxidized rapidly in the presence of H2O and O2, while they were more stable in the presence of H2O with N2 and/or CO2.

  6. Gravity wave forcing in the middle atmosphere due to reduced ozone heating during a solar eclipse

    NASA Technical Reports Server (NTRS)

    Fritts, David C.; Luo, Zhangai

    1993-01-01

    We present an analysis of the gravity wave structure and the associated forcing of the middle atmosphere induced by the screening of the ozone layer from solar heating during a solar eclipse. Fourier integral techniques and numerical evaluation of the integral solutions were used to assess the wave field structure and to compute the gravity wave forcing of the atmosphere at greater heights. Our solutions reveal dominant periods of a few hours, characteristic horizontal and vertical scales of about 5000 to 10,000 km and 200 km, respectively, and an integrated momentum flux in the direction of eclipse motion of about 5.6 x 10 exp 8 N at each height above the forcing level. These results suggest that responses to solar eclipses may be difficult to detect above background gravity wave and tidal fluctuations until well into the thermosphere. Conversely, the induced body forces may penetrate to considerable heights because of the large wave scales and will have significant effects at levels where the wave field is dissipated.

  7. Polarized Radiation Observables for Probing the Magnetism of the Outer Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Trujillo Bueno, J.

    2014-10-01

    The basic idea of optical pumping, for which Alfred Kastler received the 1966 Nobel Prize in Physics, is that the absorption and scattering of anisotropic radiation can produce population imbalances and quantum coherence among the magnetic substates of atomic levels. The degree of this radiatively-induced atomic level polarization, which is very sensitive to the presence of magnetic fields, can be determined by observing the polarization of the scattered or transmitted spectral line radiation. The most important point for solar physics is that the outer solar atmosphere is an optically pumped vapor and that the polarization of the emergent spectral line radiation can be exploited to obtain quantitative information on the strength and/or geometry of magnetic fields within the chromosphere, transition region, and corona. Here we review some recent investigations of the polarization produced by optical pumping in selected IR, FUV, and EUV spectral lines, showing that their magnetic sensitivity is suitable for probing the magnetism of the outer solar atmosphere.

  8. 3D magnetic field configuration of small-scale reconnection events in the solar plasma atmosphere

    NASA Astrophysics Data System (ADS)

    Shimizu, T.

    2015-10-01

    The outer solar atmosphere, i.e., the corona and the chromosphere, is replete with small energy-release events, which are accompanied by transient brightening and jet-like ejections. These events are considered to be magnetic reconnection events in the solar plasma, and their dynamics have been studied using recent advanced observations from the Hinode spacecraft and other observatories in space and on the ground. These events occur at different locations in the solar atmosphere and vary in their morphology and amount of the released energy. The magnetic field configurations of these reconnection events are inferred based on observations of magnetic fields at the photospheric level. Observations suggest that these magnetic configurations can be classified into two groups. In the first group, two anti-parallel magnetic fields reconnect to each other, yielding a 2D emerging flux configuration. In the second group, helical or twisted magnetic flux tubes are parallel or at a relative angle to each other. Reconnection can occur only between anti-parallel components of the magnetic flux tubes and may be referred to as component reconnection. The latter configuration type may be more important for the larger class of small-scale reconnection events. The two types of magnetic configurations can be compared to counter-helicity and co-helicity configurations, respectively, in laboratory plasma collision experiments.

  9. Fourier analysis of Solar atmospheric numerical simulations accelerated with GPUs (CUDA).

    NASA Astrophysics Data System (ADS)

    Marur, A.

    2015-12-01

    Solar dynamics from the convection zone creates a variety of waves that may propagate through the solar atmosphere. These waves are important in facilitating the energy transfer between the sun's surface and the corona as well as propagating energy throughout the solar system. How and where these waves are dissipated remains an open question. Advanced 3D numerical simulations have furthered our understanding of the processes involved. Fourier transforms to understand the nature of the waves by finding the frequency and wavelength of these waves through the simulated atmosphere, as well as the nature of their propagation and where they get dissipated. In order to analyze the different waves produced by the aforementioned simulations and models, Fast Fourier Transform algorithms will be applied. Since the processing of the multitude of different layers of the simulations (of the order of several 100^3 grid points) would be time intensive and inefficient on a CPU, CUDA, a computing architecture that harnesses the power of the GPU, will be used to accelerate the calculations.

  10. Influence of solar UV irradiance on quasi-biennial oscillations in the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Gabis, I.; Troshichev, O.

    2003-04-01

    A study of relationships between variations in the solar ultraviolet irradiance and quasi-biennial oscillations (QBO) in the Earth's atmosphere has been carried out by using the composite MgII index as a proxy of the solar UV irradiance. Detail analysis of changes in the stratospheric wind directions at layers from 10 mB to 70 mB for 1978-2001 showed that the wind changes start at higher altitudes and go down to lower ones, the wind intensity being the greatest in layer of the maximum ozone content (about 20 mB). The definite relationship between periodicity of changes in the solar UV irradiance and QBO is found: the averaged UV irradiance is obviously larger for the east QBO phase than for the west QBO phase. The reversal of stratospheric winds proceeds from the top to down with the certain ciclicity, and efficiency of the UV irradiation influence on stratosphere seems to be different at various stages of this ciclicity. As a result, the character and duration of the mean zonal wind direction in the equatorial stratosphere is determined by proper combination of the UV variation and seasonal changes in atmospheric circulation.

  11. Cloud effects on atmospheric solar absorption in light of most recent surface and satellite measurements

    NASA Astrophysics Data System (ADS)

    Hakuba, Maria Z.; Folini, Doris; Wild, Martin; Long, Charles N.; Schaepman-Strub, Gabriela; Stephens, Graeme L.

    2017-02-01

    At 36 locations worldwide, we estimate the cloud radiative effect (CREatm) on atmospheric solar absorption (ASRatm) by combining ground-based measurements of surface solar radiation (SSR) with collocated satellite-derived surface albedo and top-of-atmosphere net irradiance under both all-sky and clear-sky conditions. To derive continuous clear-sky SSR from Baseline Surface Radiation Network (BSRN) in-situ measurements of global and diffuse SSR, we make use of the Long and Ackerman (2000) algorithm that identifies clear-sky measurements and empirically fits diurnal clear-sky irradiance functions using the cosine of the solar zenith angle as the independent variable. The 11-year average (2000-2010) CREatm (all-sky minus clear-sky) is overall positive at around +11 Wm-2 using direct measurements form ground and space, and at 4 Wm-2 in the CERES EBAF dataset. This discrepancy arises from a potential overestimation in clear-sky absorption by the satellite product or underestimation by the combined BSRN/CERES dataset. The forcing ratio R shows that clouds enhance ASRatm most distinctly at desert-like locations that overall experience little occurrence of clouds. This relationship is captured by both the combined dataset and CERES EBAF.

  12. Gravity wave forcing in the middle atmosphere due to reduced ozone heating during a solar eclipse

    SciTech Connect

    Fritts, D.C.; Zhangai Luo )

    1993-02-20

    The authors present an analysis of the gravity wave structure and the associated forcing of the middle atmosphere induced by the screening of the ozone layer from solar heating during a solar eclipse. Fourier integral techniques and numerical evaluation of the integral solutions were used to assess the wave field structure and to compute the gravity wave forcing of the atmosphere at greater heights. Their solutions reveal dominant periods of a few hours, characteristic horizontal and vertical scales of [approximately]5,000 to 10,000 km and 200 km, respectively, and an integrated momentum flux in the direction of eclipse motion of [approximately]5.6 [times] 10[sup 8] N at each height above the forcing level. These results suggest that responses to solar eclipses may be difficult to detect above background gravity wave and tidal fluctuations until well into the thermosphere. Conversely, the induced body forces may penetrate to considerable heights because of the large wave scales and will have significant effects at levels where the wave field is dissipated. 38 refs., 11 figs.

  13. Atmosphere-ionosphere response to solar eclipse over Kharkiv on March 20, 2015

    NASA Astrophysics Data System (ADS)

    Chernogor, L. F.

    2016-09-01

    The results of the observations of aperiodic and quasi-periodic disturbances in E and F1 ionospheric layers and air temperature variations in the surface atmosphere on the day of the solar eclipse and control days are presented. The ionospheric processes were monitored by vertical sounding Doppler radar. The measurements showed that, near the time of the maximum coverage of the solar disk, the greatest decrease in the density of electrons in the layers E and F1 was ˜27%, which is close to the calculated value (25%). The solar eclipse was accompanied by the generation of traveling ionospheric disturbances with a period of 8-12 min and a relative amplitude of electron density variations of ˜0.6-1.5%. Because of the haze in the surface atmosphere, its temperature, which was monitored at observation points at a distance of 50-60 km from each other did not exceed 1°C near the time of the maximum eclipse magnitude.

  14. 3D magnetic field configuration of small-scale reconnection events in the solar plasma atmosphere

    SciTech Connect

    Shimizu, T.

    2015-10-15

    The outer solar atmosphere, i.e., the corona and the chromosphere, is replete with small energy-release events, which are accompanied by transient brightening and jet-like ejections. These events are considered to be magnetic reconnection events in the solar plasma, and their dynamics have been studied using recent advanced observations from the Hinode spacecraft and other observatories in space and on the ground. These events occur at different locations in the solar atmosphere and vary in their morphology and amount of the released energy. The magnetic field configurations of these reconnection events are inferred based on observations of magnetic fields at the photospheric level. Observations suggest that these magnetic configurations can be classified into two groups. In the first group, two anti-parallel magnetic fields reconnect to each other, yielding a 2D emerging flux configuration. In the second group, helical or twisted magnetic flux tubes are parallel or at a relative angle to each other. Reconnection can occur only between anti-parallel components of the magnetic flux tubes and may be referred to as component reconnection. The latter configuration type may be more important for the larger class of small-scale reconnection events. The two types of magnetic configurations can be compared to counter-helicity and co-helicity configurations, respectively, in laboratory plasma collision experiments.

  15. Solar cycle dynamics of solar, magnetospheric, and heliospheric particles, and long-term atmospheric coupling: SAMPLEX

    NASA Technical Reports Server (NTRS)

    Mason, G. M. (Principal Investigator); Hamilton, D. C.; Blake, J. B.; Mewaldt, R. A.; Stone, E. C.; Baker, D. N.; VonRosenvinge, T. T.; Callis, L. B.; Klecker, B.; Hovestadt, D.; Scholer, M.

    1996-01-01

    This report summarizes science analysis activities by the SAMPEX mission science team during the period during the period July 1, 1995 through July 1, 1996. Bibliographic entries for 1995 and 1996 to date (July 1996) are included. The SAMPEX science team was extremely active, with 20 articles published or submitted to refereed journals, 18 papers published in their entirety in Conference Proceedings, and 53 contributed papers, seminars, and miscellaneous presentations. The bibliography at the end of this report constitutes the primary description of the research activity. Science highlights are given under the major activity headings of anomalous cosmic rays, solar energetic particles, magnetospheric precipitating electrons, trapped H and He isotopes, and data analysis activities.

  16. Momentum and energy transport by waves in the solar atmosphere and solar wind

    NASA Technical Reports Server (NTRS)

    Jacques, S. A.

    1977-01-01

    The fluid equations for the solar wind are presented in a form which includes the momentum and energy flux of waves in a general and consistent way. The concept of conservation of wave action is introduced and is used to derive expressions for the wave energy density as a function of heliocentric distance. The explicit form of the terms due to waves in both the momentum and energy equations are given for radially propagating acoustic, Alfven, and fast mode waves. The effect of waves as a source of momentum is explored by examining the critical points of the momentum equation for isothermal spherically symmetric flow. We find that the principal effect of waves on the solutions is to bring the critical point closer to the sun's surface and to increase the Mach number at the critical point. When a simple model of dissipation is included for acoustic waves, in some cases there are multiple critical points.

  17. Middle Atmospheric Changes Caused by the January and March 2012 Solar Proton Events

    NASA Technical Reports Server (NTRS)

    Jackman, C. H.; Randall, C. E.; Harvey, V. L.; Wang, S.; Fleming, E. L.; Lopez-Puertas, M.; Funke, B.; Bernath, P. F.

    2014-01-01

    The recent 23-30 January and 7-11 March 2012 solar proton event (SPE) periods were substantial and caused significant impacts on the middle atmosphere. These were the two largest SPE periods of solar cycle 24 so far. The highly energetic solar protons produced considerable ionization of the neutral atmosphere as well as HOx (H, OH, HO2) and NOx (N, NO, NO2). We compute a NOx production of 1.9 and 2.1 Gigamoles due to these SPE periods in January and March 2012, respectively, which places these SPE periods among the 12 largest in the past 50 years. Aura Microwave Limb Sounder (MLS) observations of the peroxy radical, HO2, show significant enhancements of 0.9 ppbv in the northern polar mesosphere as a result of these SPE periods. Both MLS measurements and Goddard Space Flight Center (GSFC) two-dimensional (2D) model predictions indicated middle mesospheric ozone decreases of 20 percent for several days in the northern polar region with maximum depletions 60 percent as a result of the HOx produced in both the January and March 2012 SPE periods. The SCISAT-1 Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE) and the Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instruments measured NO and NO2 (NOx), which indicated enhancements of over 20 ppbv in most of the northern polar mesosphere for several days as a result of these SPE periods. The GSFC 2D model was used to predict the medium-term (months) influence and found that the polar Southern Hemisphere middle atmosphere ozone was most affected by these solar events due to the increased downward motion in the fall and early winter. The downward transport moved the SPE-produced NOy to lower altitudes and led to predicted modest destruction of ozone (5-9 percent) in the upper stratosphere days to weeks after the March 2012 event. Total ozone reductions were predicted to be a maximum of 1 percent in 2012 due to these SPEs.

  18. Atmospheric Mining in the Outer Solar System: Resource Capturing, Exploration, and Exploitation

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2015-01-01

    Atmospheric mining in the outer solar system (AMOSS) has been investigated as a means of fuel production for high-energy propulsion and power. Fusion fuels such as helium 3 (He-3) and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. 3He and hydrogen (deuterium, etc.) were the primary gases of interest, with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of AMOSS. These analyses included the gas capturing rate, storage options, and different methods of direct use of the captured gases. Additional supporting analyses were conducted to illuminate vehicle sizing and orbital transportation issues. While capturing 3He, large amounts of hydrogen and helium 4 (He-4) are produced. With these two additional gases, the potential exists for fueling small and large fleets of additional exploration and exploitation vehicles. Additional aerospacecraft or other aerial vehicles (UAVs, balloons, rockets, etc.) could fly through the outer-planet atmosphere to investigate cloud formation dynamics, global weather, localized storms or other disturbances, wind speeds, the poles, and so forth. Deep-diving aircraft (built with the strength to withstand many atmospheres of pressure) powered by the excess hydrogen or 4He may be designed to probe the higher density regions of the gas giants.

  19. Atmospheric Chemistry Effects of the 20 January 2005 Solar Proton Event

    NASA Astrophysics Data System (ADS)

    Klekociuk, A. R.; Bombardieri, D. J.; Duldig, M. L.; Michael, K. J.

    2009-03-01

    Atmospheric ionization during Solar Proton Events (SPE) has traditionally been modeled using top-of-atmosphere (TOA) particle fluxes measured by near-Earth spacecraft, and as a consequence the modeling has been restricted to particle energies below 500 MeV. However, as inferred from measurements by Earth-based muon telescopes and neutron monitors during Ground Level Enhancement (GLE) events, protons accompanying the most energetic SPEs can have significant short-term (<1 day duration) fluxes at energies up to at least 20GeV. Here, we examine atmospheric chemistry changes in the polar atmosphere during the large GLE of 20 January 2005. We use TOA particle spectra derived from satellite measurements augmented with proton spectra inferred from ground-based neutron monitor data to drive NOy and OH production in the SOCRATES two-dimensional atmospheric chemistry model. We show that the energetic particles of the January 20 event and associated particle enhancements during the preceding 5 days produced sufficient short timescale ionization in the lower stratosphere for measurable effects on HNO3 and O3 concentrations in the polar regions of both hemispheres. We also show that the detailed consideration of the most energetic particles that contributed to this GLE is of low importance for modeling ionization in the lower stratosphere, at least on a daily average timescale.

  20. Atmospheric impacts of the strongest known solar particle storm of 775 AD.

    PubMed

    Sukhodolov, Timofei; Usoskin, Ilya; Rozanov, Eugene; Asvestari, Eleanna; Ball, William T; Curran, Mark A J; Fischer, Hubertus; Kovaltsov, Gennady; Miyake, Fusa; Peter, Thomas; Plummer, Christopher; Schmutz, Werner; Severi, Mirko; Traversi, Rita

    2017-03-28

    Sporadic solar energetic particle (SEP) events affect the Earth's atmosphere and environment, in particular leading to depletion of the protective ozone layer in the Earth's atmosphere, and pose potential technological and even life hazards. The greatest SEP storm known for the last 11 millennia (the Holocene) occurred in 774-775 AD, serving as a likely worst-case scenario being 40-50 times stronger than any directly observed one. Here we present a systematic analysis of the impact such an extreme event can have on the Earth's atmosphere. Using state-of-the-art cosmic ray cascade and chemistry-climate models, we successfully reproduce the observed variability of cosmogenic isotope (10)Be, around 775 AD, in four ice cores from Greenland and Antarctica, thereby validating the models in the assessment of this event. We add to prior conclusions that any nitrate deposition signal from SEP events remains too weak to be detected in ice cores by showing that, even for such an extreme solar storm and sub-annual data resolution, the nitrate deposition signal is indistinguishable from the seasonal cycle. We show that such a severe event is able to perturb the polar stratosphere for at least one year, leading to regional changes in the surface temperature during northern hemisphere winters.

  1. Atmospheric impacts of the strongest known solar particle storm of 775 AD

    PubMed Central

    Sukhodolov, Timofei; Usoskin, Ilya; Rozanov, Eugene; Asvestari, Eleanna; Ball, William T.; Curran, Mark A. J.; Fischer, Hubertus; Kovaltsov, Gennady; Miyake, Fusa; Peter, Thomas; Plummer, Christopher; Schmutz, Werner; Severi, Mirko; Traversi, Rita

    2017-01-01

    Sporadic solar energetic particle (SEP) events affect the Earth’s atmosphere and environment, in particular leading to depletion of the protective ozone layer in the Earth’s atmosphere, and pose potential technological and even life hazards. The greatest SEP storm known for the last 11 millennia (the Holocene) occurred in 774–775 AD, serving as a likely worst-case scenario being 40–50 times stronger than any directly observed one. Here we present a systematic analysis of the impact such an extreme event can have on the Earth’s atmosphere. Using state-of-the-art cosmic ray cascade and chemistry-climate models, we successfully reproduce the observed variability of cosmogenic isotope 10Be, around 775 AD, in four ice cores from Greenland and Antarctica, thereby validating the models in the assessment of this event. We add to prior conclusions that any nitrate deposition signal from SEP events remains too weak to be detected in ice cores by showing that, even for such an extreme solar storm and sub-annual data resolution, the nitrate deposition signal is indistinguishable from the seasonal cycle. We show that such a severe event is able to perturb the polar stratosphere for at least one year, leading to regional changes in the surface temperature during northern hemisphere winters. PMID:28349934

  2. Elemental abundances in atmospheres of cool dwarfs with solar-like activity

    NASA Astrophysics Data System (ADS)

    Antipova, L. I.; Boyarchuk, A. A.

    2016-01-01

    The elemental abundances in the atmosphere of the red dwarf HD 32147, which belongs to the HR 1614 moving groups, are analyzed. The atmospheric parameters determined from spectroscopic data (the condition of equal abundances for neutral and ionized atoms of a given element) differ considerably from those derived from photometry and parallax data. The abundances of several elements are also anomalous, with the anomaly increasing with decreasing ionization potential. It is concluded that this star is a red dwarf displaying solar-like activity; i.e., having dark (cool) spots on its surface, which may sometimes be considerable in size. Modeling synthetic spectra of stars with cool spots on their surfaces, with the spectral lines consisting of two components formed in media with different temperatures, indicate that the spectroscopic atmospheric parameters derived in such cases are incorrect; this can also explain the observed dependence of the elemental abundances on the corresponding ionization potentials. This leads to the conclusion thatHD32147 is indeed a star with solar-like activity. Several other such stars considered as examples display the same anomalies as those of HD 32147. These modeling results are also valid for Ap and Am stars, and are able to explain short-wavelength observations of the Sun and some stars (the FIP effect).

  3. Atmospheric impacts of the strongest known solar particle storm of 775 AD

    NASA Astrophysics Data System (ADS)

    Sukhodolov, Timofei; Usoskin, Ilya; Rozanov, Eugene; Asvestari, Eleanna; Ball, William T.; Curran, Mark A. J.; Fischer, Hubertus; Kovaltsov, Gennady; Miyake, Fusa; Peter, Thomas; Plummer, Christopher; Schmutz, Werner; Severi, Mirko; Traversi, Rita

    2017-03-01

    Sporadic solar energetic particle (SEP) events affect the Earth’s atmosphere and environment, in particular leading to depletion of the protective ozone layer in the Earth’s atmosphere, and pose potential technological and even life hazards. The greatest SEP storm known for the last 11 millennia (the Holocene) occurred in 774-775 AD, serving as a likely worst-case scenario being 40-50 times stronger than any directly observed one. Here we present a systematic analysis of the impact such an extreme event can have on the Earth’s atmosphere. Using state-of-the-art cosmic ray cascade and chemistry-climate models, we successfully reproduce the observed variability of cosmogenic isotope 10Be, around 775 AD, in four ice cores from Greenland and Antarctica, thereby validating the models in the assessment of this event. We add to prior conclusions that any nitrate deposition signal from SEP events remains too weak to be detected in ice cores by showing that, even for such an extreme solar storm and sub-annual data resolution, the nitrate deposition signal is indistinguishable from the seasonal cycle. We show that such a severe event is able to perturb the polar stratosphere for at least one year, leading to regional changes in the surface temperature during northern hemisphere winters.

  4. Changes in atmospheric circulation between solar maximum and minimum conditions in winter and summer

    NASA Astrophysics Data System (ADS)

    Lee, Jae Nyung

    2008-10-01

    Statistically significant climate responses to the solar variability are found in Northern Annular Mode (NAM) and in the tropical circulation. This study is based on the statistical analysis of numerical simulations with ModelE version of the chemistry coupled Goddard Institute for Space Studies (GISS) general circulation model (GCM) and National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. The low frequency large scale variability of the winter and summer circulation is described by the NAM, the leading Empirical Orthogonal Function (EOF) of geopotential heights. The newly defined seasonal annular modes and its dynamical significance in the stratosphere and troposphere in the GISS ModelE is shown and compared with those in the NCEP/NCAR reanalysis. In the stratosphere, the summer NAM obtained from NCEP/NCAR reanalysis as well as from the ModelE simulations has the same sign throughout the northern hemisphere, but shows greater variability at low latitudes. The patterns in both analyses are consistent with the interpretation that low NAM conditions represent an enhancement of the seasonal difference between the summer and the annual averages of geopotential height, temperature and velocity distributions, while the reverse holds for high NAM conditions. Composite analysis of high and low NAM cases in both the model and observation suggests that the summer stratosphere is more "summer-like" when the solar activity is near a maximum. This means that the zonal easterly wind flow is stronger and the temperature is higher than normal. Thus increased irradiance favors a low summer NAM. A quantitative comparison of the anti-correlation between the NAM and the solar forcing is presented in the model and in the observation, both of which show lower/higher NAM index in solar maximum/minimum conditions. The summer NAM in the troposphere obtained from NCEP/NCAR reanalysis has a dipolar zonal structure with maximum

  5. Middle atmosphere electrodynamics: Report of the workshop on the Role of the Electrodynamics of the Middle Atmosphere on Solar Terrestrial Coupling

    NASA Technical Reports Server (NTRS)

    Maynard, N. C. (Editor)

    1979-01-01

    Significant deficiencies exist in the present understanding of the basic physical processes taking place within the middle atmosphere (the region between the tropopause and the mesopause), and in the knowledge of the variability of many of the primary parameters that regulate Middle Atmosphere Electrodynamics (MAE). Knowledge of the electrical properties, i.e., electric fields, plasma characteristics, conductivity and currents, and the physical processes that govern them is of fundamental importance to the physics of the region. Middle atmosphere electrodynamics may play a critical role in the electrodynamical aspects of solar-terrestrial relations. As a first step, the Workshop on the Role of the Electrodynamics of the Middle Atmosphere on Solar-Terrestrial Coupling was held to review the present status and define recommendations for future MAE research.

  6. Evidence of Energy Supply by Active-Region Spicules to the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Zeighami, S.; Ahangarzadeh Maralani, A. R.; Tavabi, E.; Ajabshirizadeh, A.

    2016-03-01

    We investigate the role of active-region spicules in the mass balance of the solar wind and energy supply in heating the solar atmosphere. We use high-cadence observations from the Solar Optical Telescope (SOT) onboard the Hinode satellite in the Ca ii H-line filter obtained on 26 January 2007. The observational technique provides the high spatio-temporal resolution required to detect fine structures such as spicules. We apply a Fourier power spectrum and wavelet analysis to Hinode/SOT time series of an active-region data set to explore the existence of coherent intensity oscillations. Coherent waves could be evidence of energy transport that serves to heat the solar atmosphere. Using time series, we measure the phase difference between two intensity profiles obtained at two different heights, which gives information about the phase difference between oscillations at those heights as a function of frequency. The results of a fast Fourier transform (FFT) show peaks in the power spectrum at frequencies in the range from 2 to 8 mHz at four different heights (above the limb), while the wavelet analysis indicates dominant frequencies similar to those of the Fourier power spectrum results. A coherency study indicates coherent oscillations at about 5.5 mHz (3 min). We measure mean phase speeds in the range 250-425 km s^{-1} increasing with height. The energy flux of these waves is estimated to be F = 1.8 × 106-11.2 × 106 erg cm^{-2} s^{-1} or 1.8-11.2 kW m^{-2}, which indicates that they are sufficiently energetic to accelerate the solar wind and heat the corona to temperatures of several million degrees. We compute the the mass flux carried by spicules of 3 × 10^{-10}-2 × 10^{-9} g cm^{-2} s^{-1}, which is 10-60 times higher than the mass that is carried away from the corona because of the solar wind (about 3 × 10^{-11} g cm^{-2} s^{-1}). Therefore, our results indicate that about 0.02-0.1 of the spicule mass is ejected from the corona, while the remainder reverts

  7. Deprotonated Dicarboxylic Acid Homodimers: Hydrogen Bonds and Atmospheric Implications

    SciTech Connect

    Hou, Gao-Lei; Valiev, Marat; Wang, Xue-Bin

    2016-03-31

    Dicarboxylic acids represent an important class of water-soluble organic compounds found in the atmosphere. In this work we are studying properties of dicarboxylic acid homodimer complexes (HO2(CH2)nCO2-[HO2(CH2)nCO2H], n = 0-12), as potentially important intermediates in aerosol formation processes. Our approach is based on experimental data from negative ion photoelectron spectra of the dimer complexes combined with updated measurements of the corresponding monomer species. These results are analyzed with quantum-mechanical calculations, which provide further information about equilibrium structures, thermochemical parameters associated with the complex formation, and evaporation rates. We find that upon formation of the dimer complexes the electron binding energies increase by 1.3–1.7 eV (30.0–39.2 kcal/mol), indicating increased stability of the dimerized complexes. Calculations indicate that these dimer complexes are characterized by the presence of strong intermolecular hydrogen bonds with high binding energies and are thermodynamically favorable to form with low evaporation rates. Comparison with previously studied HSO4-[HO2(CH2)2CO2H] complex (J. Phys. Chem. Lett. 2013, 4, 779-785) shows that HO2(CH2)2CO2-[HO2(CH2)2CO2H] has very similar thermochemical properties. These results imply that dicarboxylic acids not only can contribute to the heterogeneous complexes formation involving sulfuric acid and dicarboxylic acids, but also can promote the formation of homogenous complexes by involving dicarboxylic acids themselves.

  8. Upper limits to the fractionation of isotopes due to atmospheric escape: Implications for potential 14N/15N in Pluto's atmosphere

    NASA Astrophysics Data System (ADS)

    Mandt, K.; Mousis, O.

    2014-12-01

    Formation and evolution of the solar system is studied in part using stable isotope ratios that are presumed to be primordial, or representative of conditions in the protosolar Nebula. Comets, meteorites and giant planet atmospheres provide measurements that can reasonably be presumed to represent primordial conditions while the terrestrial planets, Pluto and Saturn's moon Titan have atmospheres that have evolved over the history of the solar system. The stable isotope ratios measured in these atmospheres are, therefore, first a valuable tool for evaluating the history of atmospheric escape and once escape is constrained can provide indications of conditions of formation. D/H ratios in the atmosphere of Venus provide indications of the amount of water lost from Venus over the history of the solar system, while several isotope ratios in the atmosphere of Mars provide evidence for long-term erosion of the atmosphere. We have recently demonstrated that the nitrogen ratios, 14N/15N, in Titan's atmosphere cannot evolve significantly over the history of the solar system and that the primordial ratio for Titan must have been similar to the value recently measured for NH3 in comets. This implies that the building blocks for Titan formed in the protosolar nebula rather than in the warmer subnebula surrounding Saturn at the end of its formation. Our result strongly contrasts with works showing that 14N/15N in the atmosphere of Mars can easily fractionate from the terrestrial value to its current value due to escape processes within the lifetime of the solar system. The difference between how nitrogen fractionates in Mars and Titan's atmospheres presents a puzzle for the fractionation of isotopes in an atmosphere due to atmospheric escape. Here, we present a method aiming at determining an upper limit to the amount of fractionation allowed to occur due to escape, which is a function of the escape flux and the column density of the atmospheric constituent. Through this

  9. Influence of atmospheric circulation patterns on local cloud and solar variability in Bergen, Norway

    NASA Astrophysics Data System (ADS)

    Parding, Kajsa; Olseth, Jan Asle; Liepert, Beate G.; Dagestad, Knut-Frode

    2016-08-01

    In a previous paper, we have shown that long-term cloud and solar observations (1965-2013) in Bergen, Norway (60.39°N, 5.33°E) are compatible with a largely cloud dominated radiative climate. Here, we explicitly address the relationship between the large scale circulation over Europe and local conditions in Bergen, identifying specific circulation shifts that have contributed to the observed cloud and solar variations. As a measure of synoptic weather patterns, we use the Grosswetterlagen (GWL), a daily classification of European weather for 1881-2013. Empirical models of cloud cover, cloud base, relative sunshine duration, and normalised global irradiance are constructed based on the GWL frequencies, extending the observational time series by more than 70 years. The GWL models successfully reproduce the observed increase in cloud cover and decrease in solar irradiance during the 1970s and 1980s. This cloud-induced dimming is traced to an increasing frequency of cyclonic and decreasing frequency of anticyclonic weather patterns over northern Europe. The changing circulation patterns in winter can be understood as a shift from the negative to the positive phase of the North Atlantic and Arctic Oscillation. A recent period of increasing solar irradiance is observed but not reproduce by the GWL models, suggesting this brightening is associated with factors other than large scale atmospheric circulation, possibly decreasing aerosol loads and local cloud shifts.

  10. A Mechanism Involving Solar Ultraviolet Variations for Modulating the Interannual Climatology of the Middle Atmosphere

    NASA Technical Reports Server (NTRS)

    Hood, L. L.; Jirikowic, J. L.

    1990-01-01

    In years of low solar activity, free traveling wave modes in the upper stratosphere are dominated by atmospheric normal modes such as the 16-day wave. However, within a 4-year interval centered on the 1980 to 1981 solar maximum, cross-spectral analyses of zonal mean satellite temperature data versus the solar UV flux demonstrate significant power near 27 and 13 days, providing indirect evidence that short-term UV variations were capable of exciting traveling planetary-scale waves in the upper stratosphere. Previous theoretical and observational work has indicated that interference between traveling waves and stationary waves forced from below (and the resulting oscillating latitudinal heat transports) plays a likely role in the initiation of stratospheric warmings. Researchers therefore hypothesize that the initiation of a major stratospheric warming in the upper stratosphere and lower mesosphere may depend to some extent on the amplitude of longer-period 27-day traveling waves in the upper stratosphere. This would represent a new mechanism for solar UV effects on stratospheric climatology that may be relevant to the interpretation of some recent long-term correlative results.

  11. Adaptive system for solar telescopes operating in the strongly turbulent atmosphere

    NASA Astrophysics Data System (ADS)

    Antoshkin, L. V.; Botugina, N. N.; Bolbasova, L. A.; Demidov, M. L.; Grigoriev, V. M.; Emaleev, O. N.; Konyaev, P. A.; Kopylov, E. A.; Kovadlo, P. G.; Kudryashov, A. V.; Lavrinov, V. V.; Lavrinova, L. N.; Lukin, V. P.; Shikhovtcev, A. Yu.; Trifonov, V. D.

    2016-07-01

    In this article, we describe the development of the newest adaptive optics system for the Big Solar Vacuum Telescope of the Baikal Astrophysical Observatory. This system is a result of collaboration between VE Zuev Institute of Atmospheric Optics SB RAS, Tomsk, and Institute of Solar-Terrestrial Physics SB RAS, Irkutsk. The system includes two active mirrors for the correction: domestic tip-tilt and bimorph deformable (Active Optics NightN Ltd.), and separate wavefront sensors (WFS). A correlation S-H wave-front sensor is based on a Allies Prosilica GX-1050 GigE camera with speed of 309 Hz and frame size of 1248x1248 pixels. A personal computer is used for bimorph deformable mirror image processing. The mirror was successfully used during the 2010-2014 observing seasons. The system developed is capable of correcting up to 35 modes, thus providing diffraction limited images at visible wavelengths.

  12. The solar eclipse and associated atmospheric variations observed in South Korea on 22 July 2009

    PubMed Central

    Chung, Yong Seung; Choo, Seung Ho

    2010-01-01

    A partial solar eclipse occurred in South Korea on 22 July 2009. It started at 09:30 a.m. and lasted until 12:14 LST with coverage of between 76.8% and 93.1% of the sun. The observed atmospheric effects of the eclipse are presented. It was found that from the onset of the eclipse, solar radiation was reduced by as much as 88.1 ∼ 89.9% at the present research centre. Also, during the eclipse, air temperature decreased slightly or remained almost unchanged. After the eclipse, however, it rose by 2.5 to 4.5°C at observed stations. Meanwhile, relative humidity increased and wind speeds were lowered by the eclipse. Ground-level ozone was observed to decrease during the event. PMID:20700380

  13. Solar Terrestrial Influences on the D Region as Shown by the Level of Atmospheric Radio Noise

    NASA Technical Reports Server (NTRS)

    Satori, G.; Schaning, B.

    1984-01-01

    Measurements of the integrated atmospheric radio noise field strength at 27 kHz, used here, were made from 1965 to 1975 at Uppsala, Kuhlungsborn, and Prague-Panska Ves. The large scale meteorological situation was considered by comparing solar disturbed and undisturbed periods under similar weather situations. In order to show the effects of the precipitating high energy particle (HEP) flux and of the Forbush decrease on the noise level between pairs of stations were computed as deviations from the monthly median. Delta E (dB), day by day for all six periods was studied. The correlation coefficients for noon as well as for night values were computed. The correlation coefficients were compared with those for solar undisturbed periods.

  14. Loss of atmosphere from Mars due to solar wind-induced sputtering

    NASA Technical Reports Server (NTRS)

    Kass, D. M.; Yung, Y. L.

    1995-01-01

    Because Mars does not have a strong intrinsic magnetic field, the atmosphere is eroded by interactions with the solar wind. Early solar-system conditions enhanced the sputtering loss. It is calculated that approximately 3 bars of carbon dioxide (CO2) have been sputtered over the last 3.5 billion years. This significant increase over the previous estimate by Luhmann et al. of approximately 0.14 bar of CO2 is the result of the development of a more complete model. The model also predicts slightly greater loss of water--approximately 80 meters instead of the approximately 50 meters predicted by Luhmann et al. Because estimates of CO2 on early Mars range from 0.5 to 5 bars, the 0.14-bar estimate is insignificant but the approximately 3-bar estimate will have a large effect on our understanding of the planet's evolution.

  15. Solar terrestrial influences on the D region as shown by the level of atmospheric radio noise

    NASA Astrophysics Data System (ADS)

    Satori, G.; Schaning, B.

    1984-05-01

    Measurements of the integrated atmospheric radio noise field strength at 27 kHz, used here, were made from 1965 to 1975 at Uppsala, Kuhlungsborn, and Prague-Panska Ves. The large scale meteorological situation was considered by comparing solar disturbed and undisturbed periods under similar weather situations. In order to show the effects of the precipitating high energy particle (HEP) flux and of the Forbush decrease on the noise level between pairs of stations were computed as deviations from the monthly median. Delta E (dB), day by day for all six periods was studied. The correlation coefficients for noon as well as for night values were computed. The correlation coefficients were compared with those for solar undisturbed periods.

  16. Orbit design for solar and dual satellite occultation measurements of atmospheric constituents

    NASA Technical Reports Server (NTRS)

    Brooks, D. R.; Harrison, E. F.

    1979-01-01

    Two types of satellite based occultation missions are considered for measuring atmospheric constituents. Nominal cases for each type are presented to demonstrate representative solutions to orbit design problems. For the solar occultation mode, large areas of the globe can be covered during a one year mission, but the measurements are limited to local dawn or dusk. For the dual satellite mode, with a laser aboard a second satellite to act as a source, diurnal coverage can be obtained at the expense of more complex systems and mission scenarios. In this mode, orbit pairs are selected which maintain their relative orbit plane geometry while their differing periods drive cyclic patterns of latitude coverage. A simulated one year solar occultation mission is used to illustrate one way of analyzing occultation data by averaging measurements within bands of constant latitude.

  17. The solar eclipse and associated atmospheric variations observed in South Korea on 22 July 2009.

    PubMed

    Chung, Yong Seung; Kim, Hak Sung; Choo, Seung Ho

    2010-09-01

    A partial solar eclipse occurred in South Korea on 22 July 2009. It started at 09:30 a.m. and lasted until 12:14 LST with coverage of between 76.8% and 93.1% of the sun. The observed atmospheric effects of the eclipse are presented. It was found that from the onset of the eclipse, solar radiation was reduced by as much as 88.1 approximately 89.9% at the present research centre. Also, during the eclipse, air temperature decreased slightly or remained almost unchanged. After the eclipse, however, it rose by 2.5 to 4.5 degrees C at observed stations. Meanwhile, relative humidity increased and wind speeds were lowered by the eclipse. Ground-level ozone was observed to decrease during the event.

  18. Loss of atmosphere from Mars due to solar wind-induced sputtering

    NASA Technical Reports Server (NTRS)

    Kass, D. M.; Yung, Y. L.

    1995-01-01

    Because Mars does not have a strong intrinsic magnetic field, the atmosphere is eroded by interactions with the solar wind. Early solar-system conditions enhanced the sputtering loss. It is calculated that approximately 3 bars of carbon dioxide (CO2) have been sputtered over the last 3.5 billion years. This significant increase over the previous estimate by Luhmann et al. of approximately 0.14 bar of CO2 is the result of the development of a more complete model. The model also predicts slightly greater loss of water--approximately 80 meters instead of the approximately 50 meters predicted by Luhmann et al. Because estimates of CO2 on early Mars range from 0.5 to 5 bars, the 0.14-bar estimate is insignificant but the approximately 3-bar estimate will have a large effect on our understanding of the planet's evolution.

  19. The Martian atmospheric ion escape rate dependence on solar wind and solar EUV conditions: 1. Seven years of Mars Express observations

    NASA Astrophysics Data System (ADS)

    Ramstad, Robin; Barabash, Stas; Futaana, Yoshifumi; Nilsson, Hans; Wang, Xiao-Dong; Holmström, Mats

    2015-07-01

    More than 7 years of ion flux measurements in the energy range 10 eV-15 keV have allowed the ASPERA-3/IMA (Analyzer of Space Plasmas and Energetic Ions/Ion Mass Analyzer) instrument on Mars Express to collect a large database of ion measurements in the Mars environment, over a wide range of upstream solar wind (density and velocity) and radiation (solar EUV intensity) conditions. We investigate the influence of these parameters on the Martian atmospheric ion escape rate by integrating IMA heavy ion flux measurements taken in the Martian tail at similar (binned) solar wind density (nsw), velocity (vsw), and solar EUV intensity (IEUV) conditions. For the same solar wind velocity and EUV intensity ranges (vsw and Is constrained), we find a statistically significant decrease of up to a factor of 3 in the atmospheric ion escape rate with increased average solar wind density (5.6 × 1024s-1 to 1.9 × 1024s-1 for 0.4 cm-3 and 1.4 cm-3, respectively). For low solar wind density (0.1-0.5 cm-3) and low EUV intensity, the escape rate increases with increasing solar wind velocity from 2.4 × 1024s-1 to 5.6 × 1024s-1. During high solar EUV intensities the escape fluxes are highly variable, leading to large uncertainties in the estimated escape rates; however, a statistically significant increase in the escape rate is found between low/high EUV for similar solar wind conditions. Empirical-analytical models for atmospheric escape are developed by fitting calculated escape rates to all sufficiently sampled upstream conditions.

  20. Detection of the response of ozone in the middle atmosphere to short-term solar ultraviolet variations

    NASA Astrophysics Data System (ADS)

    Keating, G. M.; Brasseur, G. P.; de Rudder, A.; Nicholson, J. Y., III

    1985-07-01

    The response of ozone to solar UV variation is determined in the middle atmosphere between the heights of 10 and 0.2 mb. The definitive isolation of the smaller variations associated with short-term solar variability is accomplished only after removal of the larger changes of ozone related to temperature variations. Using this approach the correlation coefficients between detrended ozone (Nimbus 7 LIMS) and short-term 205 nm solar variation (Nimbus 7 SBUV) are found to be much higher (0.9) than achieved in previous studies. The theoretical response time and amplitude of response of ozone in the middle atmosphere to observed short-term solar UV variations is found to be in good agreement with observations, except near 0.2 mb. The corresponding long-term response over the solar cycle is also estimated.

  1. CORRELATION BETWEEN THE 22-YEAR SOLAR MAGNETIC CYCLE AND THE 22-YEAR QUASICYCLE IN THE EARTH'S ATMOSPHERIC TEMPERATURE

    SciTech Connect

    Qu Weizheng; Zhao Jinping; Huang Fei; Deng Shenggui

    2012-07-15

    According to the variation pattern of the solar magnetic field polarity and its relation to the relative sunspot number, we established the time series of the sunspot magnetic field polarity index and analyzed the strength and polarity cycle characteristics of the solar magnetic field. The analysis showed the existence of a cycle with about a 22-year periodicity in the strength and polarity of the solar magnetic field, which proved the Hale proposition that the 11-year sunspot cycle is one-half of the 22-year solar magnetic cycle. By analyzing the atmospheric temperature field, we found that the troposphere and the stratosphere in the middle latitude of both the northern and southern hemispheres exhibited a common 22-year quasicycle in the atmospheric temperature, which is believed to be attributable to the 22-year solar magnetic cycle.

  2. Response of the upper atmosphere to variations in the solar soft x-ray irradiance. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Bailey, Scott Martin

    1995-01-01

    Terrestrial far ultraviolet (FUV) airglow emissions have been suggested as a means for remote sensing the structure of the upper atmosphere. The energy which leads to the excitation of FUV airglow emissions is solar irradiance at extreme ultraviolet (EUV) and soft x-ray wavelengths. Solar irradiance at these wavelengths is known to be highly variable; studies of nitric oxide (NO) in the lower thermosphere have suggested a variability of more than an order of magnitude in the solar soft x-ray irradiance. To properly interpret the FUV airflow, the magnitude of the solar energy deposition must be known. Previous analyses have used the electron impact excited Lyman-Birge-Hopfield (LBH) bands of N2 to infer the flux of photoelectrons in the atmosphere and thus to infer the magnitude of the solar irradiance. This dissertation presents the first simultaneous measurements of the FUV airglow, the major atmospheric constituent densities, and the solar EUV and soft x-ray irradiances. The measurements were made on three flights of an identical sounding rocket payload at different levels of solar activity. The linear response in brightness of the LBH bands to variations in solar irradiance is demonstrated. In addition to the N2 LBH bands, atomic oxygen lines at 135.6 and 130.4 nm are also studied. Unlike the LBH bands, these emissions undergo radiative transfer effects in the atmosphere. The OI emission at 135.6 nm is found to be well modeled using a radiative transfer calculation and the known excitation processes. Unfortunately, the assumed processes leading to OI 130.4 nm excitation are found to be insufficient to reproduce the observed variability of this emission. Production of NO in the atmosphere is examined; it is shown that a lower than previously reported variability in the solar soft x-ray irradiance is required to explain the variability of NO.

  3. Neutral Atmospheric Influences of the Solar Proton Events in October-November 2003

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; DeLand, Matthew T.; Labow, Gordon J.; Fleming, Eric L.; Weisenstein, Debra K.; Ko, Malcolm K. W.; Sinnhuber, Miriam; Russell, James M.

    2005-01-01

    The large solar storms in October-November 2003 caused solar proton events (SPEs) at the Earth and impacted the middle atmospheric polar cap regions. Although occurring near the end of the maximum of solar cycle 23, the fourth largest period of SPES measured in the past 40 years happened 28-31 October 2003. The highly energetic protons associated with the SPEs produced ionizations, excitations, dissociations, and dissociative ionizations of the background constituents, which led to the production of odd hydrogen (HO(sub x)) and odd nitrogen (NO(sub y)). NO(sub x) (NO + NO2) was observed by the UARS HALOE instrument to increase over 20 ppbv throughout the Southern Hemisphere polar lower mesosphere. The NOAA 16 SBUV/2 instrument measured a short-term ozone depletion of 40% in the Southern Hemisphere polar lower mesosphere, probably a result of the HO(sub x) increases. SBUV/2 observations showed ozone depletions of 5-8% in the southern polar upper stratosphere lasting days beyond the events, most likely a result of the NO(sub y) enhancements. Longer-term Northern Hemisphere polar total ozone decreases of >0.5% were predicted to last for over 8 months past the events with the Goddard Space Flight Center two-dimensional model. Although the production of NO(sub y) constituents is the same in both hemispheres, the NO(sub y) constituents have a much larger impact in the northern than the southern polar latitudes because of the seasonal differences between the two hemispheres. These observations and model computations illustrate the substantial impact of solar protons on the polar neutral middle atmosphere.

  4. Heating Mechanisms in the Low Solar Atmosphere through Magnetic Reconnection in Current Sheets

    NASA Astrophysics Data System (ADS)

    Ni, Lei; Lin, Jun; Roussev, Ilia I.; Schmieder, Brigitte

    2016-12-01

    We simulate several magnetic reconnection processes in the low solar chromosphere/photosphere; the radiation cooling, heat conduction and ambipolar diffusion are all included. Our numerical results indicate that both the high temperature (≳8 × 104 K) and low temperature (˜104 K) magnetic reconnection events can happen in the low solar atmosphere (100-600 km above the solar surface). The plasma β controlled by plasma density and magnetic fields is one important factor to decide how much the plasma can be heated up. The low temperature event is formed in a high β magnetic reconnection process, Joule heating is the main mechanism to heat plasma and the maximum temperature increase is only several thousand Kelvin. The high temperature explosions can be generated in a low β magnetic reconnection process, slow and fast-mode shocks attached at the edges of the well developed plasmoids are the main physical mechanisms to heat the plasma from several thousand Kelvin to over 8 × 104 K. Gravity in the low chromosphere can strongly hinder the plasmoid instability and the formation of slow-mode shocks in a vertical current sheet. Only small secondary islands are formed; these islands, however, are not as well developed as those in the horizontal current sheets. This work can be applied to understand the heating mechanism in the low solar atmosphere and could possibly be extended to explain the formation of common low temperature Ellerman bombs (˜104 K) and the high temperature Interface Region Imaging Spectrograph (IRIS) bombs (≳8 × 104) in the future.

  5. Atmospheric turbidity and transmittance of solar radiation in Riyadh, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    El-Shobokshy, Mohammad S.; Al-Saedi, Yaseen G.

    During the last two decades, the urban areas in the city of Riyadh—the capital of Saudi Arabia—were increasing at an exceptionally high rate through a series of development plans. The major plans had been completed by the end of 1982. Some other big utility projects were started and completed during 1987. As a consequence, the air quality has deteriorated markedly and air pollution episodes recorded during these activities showed that particulates were present in the atmosphere at high concentrations. Later in January 1991 the Gulf war started and the firing of the oil fields in Kuwait soon followed. It was estimated that soot particulates were emitted at a rate of 600 ton d -1 along with high rates of other gases. This event has led to significant air quality and visibility problems. Direct normal solar radiation has been measured during the summer months of July and August which were characterized by very dry and cloudless weather for the period between 1982 and 1992. A year-to-year trend of the transmittance of direct normal solar irradiance was then determined. The atmospheric fine aerosol (<2 μm diameter) loading data during the same period were used to establish a correlation between the aerosol concentration and the extinction coefficient. The total horizontal and direct normal solar radiation measurements during some days when the dark smoke emitted from the oil field fires in Kuwait were passing over Riyadh are presented. The reduction in solar irradiation reflects the intensity of dark smoke at a distance of 500 km from Kuwait.

  6. Changes In Atmosphere and Ionosphere Caused By Solar-geomagnetic Activity, Within Belgrade Area

    NASA Astrophysics Data System (ADS)

    Mitic, M.; Djordjevic, A.; Mihajlovic, S. J.

    Results of the different solar-climatic and terrestrial investigations show mutual con- nection between changes in the solar activity, geomagnetic field and meteorological parameters, such as: temperature, humidity and air pressure. In order to determine the influence of solar-geomagnetic activity on atmosphere and ionosphere within Bel- grade area, characteristic parameters were selected: - temperature T, as the atmosphere parameter; - critical frequency foF2 as the ionosphere parameter; - horisontal com- ponent H, as the geomagnetic field parameter; - Ri, relative Sunspot number, as the parameter of solar activity. Investigation has been done for the period from 1958-1995, which has been taken as the time interval. This period belongs to the descendent branch of the 19-th, 20- th, 21-st and 22-nd solar cycle. Values of the ionosphere parameters were considered for the 21-st cycle (as that data was available to the author). During the observation, mentioned parameters were compared in different ways. Changes were observed as behavior of mid-monthly and mid-yearly values of parameters through specific time intervals, seasons, minimums and maximums of Sun activity. It has been established that the temperature and the horisontal component of geomagnetic field have period of about 22-years and 11-years lasting period for relative Sunspots number Ri. Changes in values of ionosphere parameters were well correlated with changes of horizontal component for quiet days, values of temperature and the Sunspots number, as it was suspected. Further, secular variations were formed for more detailed investigations. The secular variation of values, for any parameter, is presented as a function of change of consec- utive yearly values in a particular time interval. By application of Fourier Transforma- tion, a spectral analysis of secular variations has been done. Changes were separated in duration of 6 and 9 months, 1, 2 and 3.5 years. In order to make a "view" on secular

  7. The relationship between the human state and external perturbations of atmospheric, geomagnetic and solar origin

    NASA Astrophysics Data System (ADS)

    Gavryuseva, E.; Kroussanova, N.

    2002-12-01

    The relationship between the state of human body and the external factors such as the different phenomena of solar activity, geomagnetic perturbations and local atmospheric characteristics is studied. The monitoring of blood pressure and electro-conductivity of human body in acupuncture points for a group fo 28 people over the period of 1.5 year has been performed daily from February 2001 to August 2002 in Capodimonte Observatory in Naples, Italy. The modified Voll method of electropuncture diagnostics was used. The strong correlation between the human body state and meteo conditions is found and the probable correlation with geomagnetic perturbations is discussed.

  8. STABILITY AND DYNAMICS OF A FLUX ROPE FORMED VIA FLUX EMERGENCE INTO THE SOLAR ATMOSPHERE

    SciTech Connect

    An, J. M.; Magara, T. E-mail: magara@khu.ac.kr

    2013-08-10

    We study the stability and dynamics of a flux rope formed through the emergence of a twisted magnetic flux tube into the solar atmosphere. A three-dimensional magnetohydrodynamic simulation has been performed to investigate several key factors affecting the dynamics of the flux rope. The stability of the flux rope is examined by deriving the decay index of the coronal magnetic field surrounding the flux rope. We investigate a transition between the quasi-static and dynamic states of the flux rope through an analysis of the curvature and scale height of emerging magnetic field. A practical application of this analysis for global eruptions is also considered.

  9. Non-LTE profiles of the Al I autoionization lines. [for solar model atmospheres

    NASA Technical Reports Server (NTRS)

    Finn, G. D.; Jefferies, J. T.

    1974-01-01

    A non-LTE formulation is given for the transfer of radiation in the autoionizing lines of neutral aluminum at 1932 and 1936 A through both the Bilderberg and Harvard-Smithsonian model atmospheres. Numerical solutions for the common source function of these lines and their theoretical line profiles are calculated and compared with the corresponding LTE profiles. The results show that the non-LTE profiles provide a better match with the observations. They also indicate that the continuous opacity of the standard solar models should be increased in this wavelength region if the center-limb variations of observed and theoretical profiles of these lines are to be in reasonable agreement.

  10. Measurements of solar flare enhancements to the single event upset environment in the upper atmosphere

    NASA Astrophysics Data System (ADS)

    Dyer, C. S.; Sims, A. J.; Farren, J.; Stephen, J.

    1990-12-01

    The Cosmic Radiation Environment Monitor has flow regularly on a supersonic airliner over a period of 18 months in order to explore the extent of single-event phenomena in the upper atmosphere. Data presented are from flights occurring between November 1988 and May 1990. The detector system used is briefly described. Quiet-time data now have good statistical precision and are compared with predictions of environment models. A number of increases and decreases were observed during the solar flare events of September and October 1989.

  11. HEATING THE SOLAR ATMOSPHERE BY THE SELF-ENHANCED THERMAL WAVES CAUSED BY THE DYNAMO PROCESSES

    SciTech Connect

    Dumin, Yurii V. E-mail: dumin@izmiran.ru

    2012-05-20

    We discuss a possible mechanism for heating the solar atmosphere by the ensemble of thermal waves, generated by the photospheric dynamo and propagating upward with increasing magnitudes. These waves are self-sustained and amplified due to the specific dependence of the efficiency of heat release by Ohmic dissipation on the ratio of the collisional to gyrofrequencies, which in its turn is determined by the temperature profile formed in the wave. In the case of sufficiently strong driving, such a mechanism can increase the plasma temperature by a few times, i.e., it may be responsible for heating the chromosphere and the base of the transition region.

  12. Observed Spatial Properties of the Solar Eigenfunctions and the Implications for the Existence of Resolved Multiplets

    NASA Technical Reports Server (NTRS)

    Caudell, T. P.; Hill, H. A.; Bos, R. J.

    1984-01-01

    Solar oscillations are manifested in the solar atmosphere as spatial and temporal perturbations in the local thermodynamical and mechanical properties. When measuring the solar radius/diameter, these perturbations enter the observation through changes in the radiative source function and opacity at the extreme limb. When compared to the disk center, the observable portion of these perturbations is changed in spatial character by projection effects and oblique optical depth geometry. The time varying solar radius signal at SCLERA (Santa Catalina Laboratory for Experimental Relativity) is produced by an edge definition sensitive to the resultant changes in the spatial shape of the limb intensity profile. An attempt is made to further determine the shape and properties of the limb signals which display global solar oscillations.

  13. Differential rotation in a solar-driven quasi-axisymmetric circulation. [of planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Harris, I.; Chan, K. L.

    1984-01-01

    The concept of a quasi-axisymmetric circulation is used to explore the global scale dynamics of planetary atmospheres. A numerical circulation model applicable to Jupiter is presented, and an analytical study is performed elucidating the conditions leading to differential rotation in an atmosphere which is convectively unstable. A linear system forced by solar differential heating is considered, with nonlinear effects arising from advection being represented in the form of eddy diffusion. An empirical, latitudinal spectrum of the observed zonal wind field on Jupiter is discussed. Numerical solutions are presented which reveal banded wind fields with alternating and equatorial zonal jets and a multicellular Ferrel-Thomson meridional circulation consistent with the observed cloud striations on Jupiter. The vertical derivatives are parameterized to construct a simplified one-layer model.

  14. Science on Spacelab. [astronomy, high energy astrophysics, life sciences, and solar, atmospheric and space physics

    NASA Technical Reports Server (NTRS)

    Schmerling, E. R.

    1977-01-01

    Spacelab was developed by the European Space Agency for the conduction of scientific and technological experiments in space. Spacelab can be taken into earth orbit by the Space Shuttle and returned to earth after a period of 1-3 weeks. The Spacelab modular system of pallets, pressurized modules, and racks can contain large payloads with high power and telemetry requirements. A working group has defined the 'Atmospheres, Magnetospheres, and Plasmas-in-Space' project. The project objectives include the absolute measurement of solar flux in a number of carefully selected bands at the same time at which atmospheric measurements are made. NASA is committed to the concept that the scientist is to play a key role in its scientific programs.

  15. Atmospheric performance of the special-purpose Solar Energy Research Institute (SERI) thin-airfoil family

    SciTech Connect

    Tangler, J; Smith, B; Jager, D; Olsen, T

    1990-09-01

    The Solar Energy Research Institute (SERI), in cooperation with SeaWest Energy Group, has completed extensive atmospheric testing of the special-purpose SERI thin-airfoil family during the 1990 wind season. The purpose of this test program was to experimentally verify the predicted performance characteristics of the thin-airfoil family on a geometrically optimized blade, and to compare it to original-equipment blades under atmospheric wind conditions. The tests were run on two identical Micon 65/13 horizontal-axis wind turbines installed side-by-side in a wind farm. The thin-airfoil family 7.96 m blades were installed on one turbine, and AeroStar 7.41 m blades were installed on the other. This paper presents final performance results of the side-by-side comparative field test for both clean and dirty blade conditions. 7 refs., 11 figs., 1 tab.

  16. Global Atmospheric Inversions of XCO2 and Solar-Induced Fluorescence (SIF) from OCO-2

    NASA Astrophysics Data System (ADS)

    Schuh, A. E.; Denning, S.; Baker, I. T.; Haynes, K. D.; Geyer, N. M.; McKeown, R.

    2016-12-01

    The OCO-2 satellite was launched on July 2, 2014, to monitor global atmospheric concentration and flux of CO2 from space. We present a novel new atmospheric inversion scheme that solves for respiration and gross primary production (GPP) using a decomposition of multiplicative biases into seasonal harmonics in combination with solar induced fluorescence. Initial CO2 flux results for the time period of September 2014 to March 2016 will be presented with a focus on temporal corrections to the flux and an "in line" bias correction that allows fluxes to be solved for simultaneously with observational bias allowing for a posterior covariance between observational bias and flux errors. Separation of flux terms into mechanistic components then allows comparison to independent estimates such as eddy covariance data and inventory based data such as harvest yields.

  17. Pressure sensing of the atmosphere by solar occultation using broadband CO(2) absorption.

    PubMed

    Park, J H; Russell Iii, J M; Drayson, S R

    1979-06-15

    A technique for obtaining pressure at the tangent point in an IR solar occultation experiment is described. By measuring IR absorption in bands of atmospheric CO(2) (e.g., 2.0 microm, 2.7 microm, or 4.3 microm), mean pressure values for each tangent point layer (vertical thickness 2 km or less) of the atmosphere can be obtained with rms errors of less than 3%. The simultaneous retrieval of pressure and gas concentration in a remote-sensing experiment will increase the accuracy of inverted gas concentrations and minimize the dependence of the experiment on pressure or mass path error resulting from use of climatological pressure data, satellite ephemeris, and instrument pointing accuracy.

  18. Science on Spacelab. [astronomy, high energy astrophysics, life sciences, and solar, atmospheric and space physics

    NASA Technical Reports Server (NTRS)

    Schmerling, E. R.

    1977-01-01

    Spacelab was developed by the European Space Agency for the conduction of scientific and technological experiments in space. Spacelab can be taken into earth orbit by the Space Shuttle and returned to earth after a period of 1-3 weeks. The Spacelab modular system of pallets, pressurized modules, and racks can contain large payloads with high power and telemetry requirements. A working group has defined the 'Atmospheres, Magnetospheres, and Plasmas-in-Space' project. The project objectives include the absolute measurement of solar flux in a number of carefully selected bands at the same time at which atmospheric measurements are made. NASA is committed to the concept that the scientist is to play a key role in its scientific programs.

  19. Mars atmospheric loss and isotopic fractionation by solar-wind-induced sputtering and photochemical escape

    NASA Technical Reports Server (NTRS)

    Jakosky, Bruce M.; Pepin, Robert O.; Johnson, Robert E.; Fox, J. L.

    1994-01-01

    We examine the effects of the loss of Mars atmospheric constituents by solar-wind-induced sputtering and by photochemical escape during the past 3.8 billion years. Sputtering is capable of efficiently removing species from the upper atmosphere, including the light noble gases; nitrogen and oxygen are removed by photochemical processes as well. Due to diffusive separation (by mass) above the homopause, removal from the top of the atmosphere will fractionate the isotopes of each species, with the lighter mass being preferentially lost. For carbon and oxygen, this allows us to determine the size of nonatmospheric reservoirs which mix with the atmosphere; these reservoirs can be CO2 adsorbed in the regolith and H2O in the polar ice caps. We have constructed both simple analytical models and time-dependent models of the loss of volatiles from and supply to the martian atmosphere. Both argon and neon require continued replenishment from outgassing over geologic time. For argon, sputtering loss explains the fractionation of (Ar-36)/(Ar-38) without requiring a distinct epoch of hydrodynamic escape (although fractionation of Xe isotopes still requires very early hydrodynamic loss). For neon, the current (Ne-22)/(Ne-20) ratio represents a balance between loss to space and continued resupply from the interior; the similarity of the ratio to the terrestrial value is coincidental. For nitrogen, the loss by both sputtering and photochemical escape would produce a fractionation of (N-15)/(N-14) larger than observed; an early, thicker carbon dioxide atmosphere could mitigate the nitrogen loss and produce the observed fractionation, as could continued outgassing of juvenile nitorgen. Based on the isotopic constraints, the total amount of carbon dioxide lost over geologic time is probably on the order of tens of millibars rather than a substantial fraction of a bar. The total loss from solar-wind-induced sputtering and photochemical escape, therefore, does not seem able to explain

  20. Mars atmospheric loss and isotopic fractionation by solar-wind-induced sputtering and photochemical escape

    NASA Technical Reports Server (NTRS)

    Jakosky, Bruce M.; Pepin, Robert O.; Johnson, Robert E.; Fox, J. L.

    1994-01-01

    We examine the effects of the loss of Mars atmospheric constituents by solar-wind-induced sputtering and by photochemical escape during the past 3.8 billion years. Sputtering is capable of efficiently removing species from the upper atmosphere, including the light noble gases; nitrogen and oxygen are removed by photochemical processes as well. Due to diffusive separation (by mass) above the homopause, removal from the top of the atmosphere will fractionate the isotopes of each species, with the lighter mass being preferentially lost. For carbon and oxygen, this allows us to determine the size of nonatmospheric reservoirs which mix with the atmosphere; these reservoirs can be CO2 adsorbed in the regolith and H2O in the polar ice caps. We have constructed both simple analytical models and time-dependent models of the loss of volatiles from and supply to the martian atmosphere. Both argon and neon require continued replenishment from outgassing over geologic time. For argon, sputtering loss explains the fractionation of (Ar-36)/(Ar-38) without requiring a distinct epoch of hydrodynamic escape (although fractionation of Xe isotopes still requires very early hydrodynamic loss). For neon, the current (Ne-22)/(Ne-20) ratio represents a balance between loss to space and continued resupply from the interior; the similarity of the ratio to the terrestrial value is coincidental. For nitrogen, the loss by both sputtering and photochemical escape would produce a fractionation of (N-15)/(N-14) larger than observed; an early, thicker carbon dioxide atmosphere could mitigate the nitrogen loss and produce the observed fractionation, as could continued outgassing of juvenile nitorgen. Based on the isotopic constraints, the total amount of carbon dioxide lost over geologic time is probably on the order of tens of millibars rather than a substantial fraction of a bar. The total loss from solar-wind-induced sputtering and photochemical escape, therefore, does not seem able to explain

  1. Experimental simulation of the atmospheric ablation of cosmic dust particles: implications for HPLA radar and lidar observations

    NASA Astrophysics Data System (ADS)

    Gomez Martin, Juan Carlos; Bones, David; Diego Carrillo Sanchez, Juan; James, Alexander; Janches, Diego; Plane, John

    2016-04-01

    The inner solar system is full of interplanetary dust particles (IDPs) originating from cometary trails and collisions between asteroids. The entry and evaporation of IDPs in planetary atmospheres is related to a variety of phenomena including formation of mesospheric metal layers and clouds and stratospheric aerosol chemistry. The estimated mass flux into the Earth's Atmosphere from modelling of Zodiacal Cloud observations combined with results from our chemical ablation model (CABMOD) is consistent with the deposition rate of cosmic spherules on the ice caps. However, the fluxes derived from modelling HPLA radar observations, which also uses CABMOD, are significantly lower. In addition, all models underestimate the observed Na/Fe ratio in metal layers observed by LIDAR, and the radar-based model in particular does not predict differential ablation. In order to address these inconsistencies, we have built a laboratory meteor ablation simulator, which enables us to observe and characterise the ablation of metal atoms from meteoritic IDP analogues. CABMOD can be then benchmarked against the laboratory data. In this presentation, the implications of our experimental results for the interpretation of radar field observations, mass flux estimates and modelling of metal layers will be discussed.

  2. Atmospheric Mining in the Outer Solar System: Outer Planet Orbital Transfer and Lander Analyses

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2016-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and deuterium can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and deuterium were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate, storage options, and different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. Analyses of orbital transfer vehicles (OTVs), landers, and the issues with in-situ resource utilization (ISRU) mining factories are included. Preliminary observations are presented on near-optimal selections of moon base orbital locations, OTV power levels, and OTV and lander rendezvous points. For analyses of round trip OTV flights from Uranus to Miranda or Titania, a 10-Megawatt electric (MWe) OTV power level and a 200-metric ton (MT) lander payload were selected based on a relative short OTV trip time and minimization of the number of lander flights. A similar optimum power level is suggested for OTVs flying from low orbit around Neptune to Thalassa or Triton. Several moon base sites at Uranus and Neptune and the OTV requirements to support them are also addressed.

  3. Atmospheric Mining in the Outer Solar System: Outer Planet Orbital Transfer and Lander Analyses

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2016-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and deuterium can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and deuterium were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate, storage options, and different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. Analyses of orbital transfer vehicles (OTVs), landers, and the issues with in-situ resource utilization (ISRU) mining factories are included. Preliminary observations are presented on near-optimal selections of moon base orbital locations, OTV power levels, and OTV and lander rendezvous points. For analyses of round trip OTV flights from Uranus to Miranda or Titania, a 10- Megawatt electric (MWe) OTV power level and a 200 metricton (MT) lander payload were selected based on a relative short OTV trip time and minimization of the number of lander flights. A similar optimum power level is suggested for OTVs flying from low orbit around Neptune to Thalassa or Triton. Several moon base sites at Uranus and Neptune and the OTV requirements to support them are also addressed.

  4. On the presence of electric currents in the solar atmosphere. I - A theoretical framework

    NASA Technical Reports Server (NTRS)

    Hagyard, M.; Low, B. C.; Tandberg-Hanssen, E.

    1981-01-01

    The general magnetic field above the solar photosphere is divided by an elementary analysis based on Ampere's law into two parts: a potential field due to electric currents below the photosphere and a field produced by electric currents above the photosphere combined with the induced mirror currents. The latter, by symmetry, has a set of field lines lying in the plane taken to be the photosphere which may be constructed from given vector magnetograph measurements. These field lines also represent all the information on the electric currents above the photosphere that a magnetograph can provide. Theoretical illustrations are given, and implications for data analysis are discussed.

  5. Magnetic Cloud Bz solar cycle variation and the space weather implications

    NASA Astrophysics Data System (ADS)

    Li, Y.; Luhmann, J. G.; Jian, L.; Russell, C. T.

    2016-12-01

    The relationship between magnetic cloud (MC) polarity and the solar magnetic field polarity cycle is extended up to the present. In spite of the weak solar polar fields, the related complications of helmet streamer belt and source surface neutral line over the recent solar cycle, the MC polarity solar cycle variation pattern continues to be true. A trend related to the long solar minimum between cycles 23 and 24are longer periods of N-S polarity MCs. The MC polarity patterns at the STEREO sites generally reflect that at L1. Combining the MC events at three observing points (L1 and STEREO A&B) provides a larger data sample, and the normalized result reenforce and clarify the MC polarity trend. We conclude with some discussions regarding source regions and space weather implications.

  6. The Effects of Non-Sphericity in Diagnosis of Solar and Stellar Atmospheres

    NASA Astrophysics Data System (ADS)

    Pecker, Jean-Claude

    1996-12-01

    Between the interplanetary medium, filled by winds, magnetic structures, etc., and the interior of stars, opaque, and dominated heavily by the gravitational spherical field, the stellar atmosphere is a place where the true physical equilibrium, on the inside, sufficiently described by the parameters L,