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Sample records for earth atmosphere

  1. Earth's changeable atmosphere

    NASA Astrophysics Data System (ADS)

    2016-06-01

    Billions of years ago, high atmospheric greenhouse gas concentrations were vital to life's tenuous foothold on Earth. Despite new constraints, the composition and evolution of Earth's early atmosphere remains hazy.

  2. 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.

  3. Solar energy and its interaction with Earth`s atmosphere

    SciTech Connect

    Tulunay, Y. ||

    1993-12-31

    The Sun is responsible for many of the phenomena on Earth, including the maintenance of life. In addition, magnetic storms, capable of disrupting radio communication, and auroral displays are associated with solar events. Man-made electrical, satellite, and communication systems are affected strongly by the near-Earth space environments. The purpose of this paper is to review briefly the interaction of solar activity with the near-Earth environment. These processes can be studied by examing two sets of interactions. That is, the interaction of the solar electromagnetic output with the Earth`s neutral atmosphere, and the solar corpuscular output with the geomagnetic field. In order to understand the types of interactions one needs to know more details of the interacting components. Therefore, the near-Earth environments which comprise neutral atmospheric, ionospheric and magnetospheric regions will be discussed in relation to the direct and indirect influences of solar activity.

  4. Simulating super earth atmospheres in the laboratory

    NASA Astrophysics Data System (ADS)

    Claudi, R.; Erculiani, M. S.; Galletta, G.; Billi, D.; Pace, E.; Schierano, D.; Giro, E.; D'Alessandro, M.

    2016-01-01

    Several space missions, such as JWST, TESS and the very recently proposed ARIEL, or ground-based experiments, as SPHERE and GPI, have been proposed to measure the atmospheric transmission, reflection and emission spectra of extrasolar planets. The planet atmosphere characteristics and possible biosignatures will be inferred by studying planetary spectra in order to identify the emission/absorption lines/bands from atmospheric molecules such as water (H2O), carbon monoxide (CO), methane (CH4), ammonia (NH3), etc. In particular, it is important to know in detail the optical characteristics of gases in the typical physical conditions of the planetary atmospheres and how these characteristics could be affected by radiation driven photochemical and biochemical reaction. The main aim of the project `Atmosphere in a Test Tube' is to provide insights on exoplanet atmosphere modification due to biological intervention. This can be achieved simulating planetary atmosphere at different pressure and temperature conditions under the effects of radiation sources, used as proxies of different bands of the stellar emission. We are tackling the characterization of extrasolar planet atmospheres by mean of innovative laboratory experiments described in this paper. The experiments are intended to reproduce the conditions on warm earths and super earths hosted by low-mass M dwarfs primaries with the aim to understand if a cyanobacteria population hosted on a Earth-like planet orbiting an M0 star is able to maintain its photosynthetic activity and produce traceable signatures.

  5. Atmospheric electricity and aerosol-cloud interactions in earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Manninen, Hanna E.; Tammet, Hannes; Mäkelä, Antti; Haapalainen, Jussi; Mirme, Sander; Nieminen, Tuomo; Franchin, Alessandro; Petäjä, Tuukka; Kulmala, Markku; Hõrrak, Urmas

    2013-05-01

    Firstly, atmospheric ions play an important role in the fair weather electricity in Earth's atmosphere. Small ions, or charged molecular clusters, carry electric currents in the atmosphere. These small ions are continuously present, and their lifetime in lower atmosphere is about one minute. It's essential to find out a connection between the production rate of cluster ions, ion-ion recombination, and ion-aerosol attachment, and their ambient concentrations, in order to understand electrical properties of air. Secondly, atmospheric ions are important for Earth's climate, due to their potential role in secondary aerosol formation, which can lead to increased number of cloud condensation nuclei (CCN), which in turn can change the cloud properties. Our aim is to quantify the connections between these two important roles of air ions based on field observations.

  6. Earth Atmosphere Observatory Formation at L2

    NASA Technical Reports Server (NTRS)

    Mettler, Edward; Acikmese, A. Behcet; Breckenridge, William G.; Mecenka, Steven A.; Tubbs, Eldred F.

    2004-01-01

    This paper is a product of research supported by NASA under RASC (the Revolutionary Aerospace Systems Concepts) program. It presents an overall system architecture, and covers issues of deployment, navigation, and control related to a formation of two spacecraft in the neighborhood of the Sun-Earth L2 Lagrange point (on the Sun-Earth line), that serves as an observatory of Earth's atmosphere. The observatory concept definition study was a multi-center NASA effort conducted in 2003, and covered a much wider scope than is presented in this focused paper.The Earth observatory at L2 is a unique design concept that can improve the knowledge and understanding of dynamic, chemical and radiative mechanisms that cause changes in the atmosphere, and can lead to the development of models and techniques to predict short and long-term climate changes.

  7. Evolution of the Earth's Atmosphere.

    PubMed

    Rasool, S I

    1967-09-22

    We living things are a late outgrowth of the metabolism of our Galaxy. The carbon that enters so importantly into our composition was cooked in the remote past in a dying star. From it at lower temperatures nitrogen and oxygen were formed. These, our indispensable elements, were spewed out into space in the exhalations of red giants and such stellar catastrophes as supernovae, there to be mixed with hydrogen, to form eventually the substance of the sun and planets, and ourselves. The waters of ancient seas set the pattern of ions in our blood. The ancient atmospheres molded our metabolism. PMID:17819549

  8. ATMOSPHERES OF HOT SUPER-EARTHS

    SciTech Connect

    Castan, Thibaut; Menou, Kristen

    2011-12-20

    Hot super-Earths likely possess minimal atmospheres established through vapor saturation equilibrium with the ground. We solve the hydrodynamics of these tenuous atmospheres at the surface of CoRot-7b, Kepler-10b, and 55 Cnc-e, including idealized treatments of magnetic drag and ohmic dissipation. We find that atmospheric pressures remain close to their local saturation values in all cases. Despite the emergence of strongly supersonic winds which carry sublimating mass away from the substellar point, the atmospheres do not extend much beyond the day-night terminators. Ground temperatures, which determine the planetary thermal (infrared) signature, are largely unaffected by exchanges with the atmosphere and thus follow the effective irradiation pattern. Atmospheric temperatures, however, which control cloud condensation and thus albedo properties, can deviate substantially from the irradiation pattern. Magnetic drag and ohmic dissipation can also strongly impact the atmospheric behavior, depending on atmospheric composition and the planetary magnetic field strength. We conclude that hot super-Earths could exhibit interesting signatures in reflection (and possibly in emission) which would trace a combination of their ground, atmospheric, and magnetic properties.

  9. Infrared Heterodyne Earth Atmospheric Remote Spectrometer (IHEARS)

    NASA Astrophysics Data System (ADS)

    Kostiuk, T.; Hanisco, T. F.; Newman, P. A.; Olsen, M. A.; Hewagama, T.; Livengood, T. A.

    2013-12-01

    We will describe the design and capability of the Goddard Space Flight Center Infrared Heterodyne Earth Atmospheric Remote Spectrometer (IHEARS) capable of unique altitude-resolved measurements of chemical and physical processes within the Earth's upper troposphere through the lower mesosphere. Ultra-high spectral resolving power (R>1,000,000) and frequency precision in the 7 to 11 μm wavelength band enables measuring true molecular spectral line shapes with no instrumental effects, thus retrieving small changes in major atmospheric gases, detecting trace species, retrieving temperatures, and measuring Doppler-shift due to winds. These parameters can be obtained from the same set of measurements, a unique capability for Earth remote-sensing. In solar occultation, e.g., from the International Space Station, measurements of abundance changes in <0.5 km layers can yield extremely high sensitivity, e.g., O3 (1ppb), CO2 (1ppm), H2O (<0.5ppm), all at >15-sigma confidence level, enhancing the study of transport and chemistry in upper-troposphere/lower-stratosphere and tropical-transition-layer regions, thereby addressing and constraining GCMs and climate-change models. The technique has a long heritage in ground-based instrumentation and measurements of planetary atmospheres, with proven results paralleling the capability for Earth observations. The proposed detection concept, instrument design and its remote operation and capabilities from Earth orbit will be presented. The proposed instrument will have lower volume, mass, and power requirements compared to existing Earth-science instruments, while enabling new and unique Earth observation measurements from a variety of space platforms. The ultimate projected space flight application will be on Earth Venture Class science missions, the ISS, and future Earth and planetary missions such as GACM.

  10. Atmospheric nitrogen evolution on Earth and Venus

    NASA Astrophysics Data System (ADS)

    Wordsworth, R. D.

    2016-08-01

    Nitrogen is the most common element in Earth's atmosphere and also appears to be present in significant amounts in the mantle. However, its long-term cycling between these two reservoirs remains poorly understood. Here a range of biotic and abiotic mechanisms are evaluated that could have caused nitrogen exchange between Earth's surface and interior over time. In the Archean, biological nitrogen fixation was likely strongly limited by nutrient and/or electron acceptor constraints. Abiotic fixation of dinitrogen becomes efficient in strongly reducing atmospheres, but only once temperatures exceed around 1000 K. Hence if atmospheric N2 levels really were as low as they are today 3.0-3.5 Ga, the bulk of Earth's mantle nitrogen must have been emplaced in the Hadean, most likely at a time when the surface was molten. The elevated atmospheric N content on Venus compared to Earth can be explained abiotically by a water loss redox pump mechanism, where oxygen liberated from H2O photolysis and subsequent H loss to space oxidises the mantle, causing enhanced outgassing of nitrogen. This mechanism has implications for understanding the partitioning of other Venusian volatiles and atmospheric evolution on exoplanets.

  11. Atmospheric neutrino oscillations for Earth tomography

    NASA Astrophysics Data System (ADS)

    Winter, Walter

    2016-07-01

    Modern proposed atmospheric neutrino oscillation experiments, such as PINGU in the Antarctic ice or ORCA in Mediterranean sea water, aim for precision measurements of the oscillation parameters including the ordering of the neutrino masses. They can, however, go far beyond that: Since neutrino oscillations are affected by the coherent forward scattering with matter, neutrinos can provide a new view on the interior of the earth. We show that the proposed atmospheric oscillation experiments can measure the lower mantle density of the earth with a precision at the level of a few percent, including the uncertainties of the oscillation parameters and correlations among different density layers. While the earth's core is, in principle, accessible by the angular resolution, new technology would be required to extract degeneracy-free information.

  12. Energetic Particle Influence on the Earth's Atmosphere

    NASA Astrophysics Data System (ADS)

    Mironova, Irina A.; Aplin, Karen L.; Arnold, Frank; Bazilevskaya, Galina A.; Harrison, R. Giles; Krivolutsky, Alexei A.; Nicoll, Keri A.; Rozanov, Eugene V.; Turunen, Esa; Usoskin, Ilya G.

    2015-11-01

    This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth's atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere.

  13. Earth's Climate: The Ocean-Atmosphere Interaction

    NASA Astrophysics Data System (ADS)

    Lifland, Jonathan

    2004-11-01

    A new AGU book, Earth's Climate: The Ocean-Atmosphere Interaction, edited by Chunzai Wang, Shang-Ping Xie, and James A. Carton, presents current observations, theories, and models of ocean-atmosphere interaction that helps shape climate and its variations over the global ocean. The book represents the climate community's first effort to summarize the modern science of ocean-atmosphere interaction and the roles that the interaction play in climate variability in the Pacific, Atlantic, and Indian Oceans as well as interactions across basins and between the tropics and extratropics. In this issue, Eos talks with lead editor Chunzai Wang. Wang is a research oceanographer at the Physical Oceanography Division of the National Oceanic and Atmospheric Administration's Atlantic Oceanographic and Meteorological Laboratory, in Miami, Florida.

  14. Oxidants and oxidation in the Earth's atmosphere

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The 1994 BOC Priestley Conference was held at Bucknell University in Lewisburg, Pennsylvania, from June 24 through June 27, 1994. This conference, managed by the American Chemical Society (ACS), was a joint celebration with the Royal Society of Chemistry (RSC) commemorating Joseph Priestley's arrival in the U.S. and his discovery of oxygen. The basic theme of the conference was 'Oxidants and Oxidation in the Earth's Atmosphere,' with a keynote lecture on the history of ozone. A distinguished group of U.S. and international atmospheric chemists addressed the issues dominating current research and policy agendas. Topics crucial to the atmospheric chemistry of global change and local and regional air pollution were discussed. The program for the conference included four technical sessions on the following topics: (1) Oxidative Fate of Atmospheric Pollutants; (2) Photochemical Smog and Ozone; (3) Stratospheric Ozone; and (4) Global Tropospheric Ozone.

  15. [How did the earth's oxygen atmosphere originate?].

    PubMed

    Schäfer, G

    2004-09-01

    The planet earth did not carry an oxygen atmosphere from the beginning. Though oxygen could arise from radiation mediated water splitting, these processes were not efficient enough to create a global gas atmosphere. Oxygen in the latter is a product of the photosynthetic activity of early green organisms. Only after biological mass-formation of oxygen the UV-protective ozone layer could develop, then enabeling life to move from water onto land. This took billions of years. The basics of the processes of biological oxygen liberation and utilization are described in the following as well as the importance of their steady state equilibrium. Also a hint is given to oxygen as a toxic compound though being a chemical prerequisite for aerobic life on earth. PMID:15490337

  16. Background Lamb waves in the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Nishida, K.; Kobayashi, N.; Fukao, Y.

    2013-12-01

    Lamb waves of the Earth's atmosphere in the millihertz band have been considered as transient phenomena excited only by large events [e.g. the major volcanic eruption of Krakatoa in 1833, the impact of Siberian meteorite in 1908, the testing of large nuclear tests and the huge earthquakes, Garrett1969]. In a case of the solid Earth, observation of background free oscillations in the millihertz band-now known as Earth's background free oscillations or seismic hum, has been firmly established. Above 5 mHz, their dominant excitation sources are oceanic infragravity waves. At 3.7 and 4.4 mHz an elasto-acoustic resonance between the solid Earth and the atmosphere was observed [Nishida et al., 2000]. These seismic observations show that the contribution of atmospheric disturbances to the seismic hum is dominant below 5 mHz. Such contribution implies background excitations of acoustic-gravity waves in this frequency range. For direct detection of the background acoustic-gravity waves, our group conducted observations using an array of barometers [Nishida et al. 2005]. However, the spatial scale of the array of about 10 km was too small to detect acoustic modes below 10 mHz. Since then, no direct observations of these waves have been reported. In 2011, 337 high-resolution microbarometers were installed on a continental scale at USArray Transportable Array. The large and dense array enables us to detect the background atmospheric waves. Here, we show the first evidence of background Lamb waves in the Earth's atmosphere from 0.2 to 10 mHz, based on the array analysis of microbarometer data from the USArray in 2012. The observations suggest that the excitation sources are atmospheric disturbances in the troposphere. Theoretically, their energy in the troposphere tunnels into the thermosphere at a resonant frequency via thermospheric gravity wave, where the observed amplitudes indeed take a local minimum. The energy leak through the frequency window could partly contribute to

  17. Cosmic dust in the earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Plane, John M. C.

    2012-04-01

    This review discusses the magnitude of the cosmic dust input into the earth's atmosphere, and the resulting impacts from around 100 km to the earth's surface. Zodiacal cloud observations and measurements made with a spaceborne dust detector indicate a daily mass input of interplanetary dust particles ranging from 100 to 300 tonnes, which is in agreement with the accumulation rates of cosmic-enriched elements (Ir, Pt, Os and super-paramagnetic Fe) in polar ice cores and deep-sea sediments. In contrast, measurements in the middle atmosphere - by radar, lidar, high-flying aircraft and satellite remote sensing - indicate that the input is between 5 and 50 tonnes per day. There are two reasons why this huge discrepancy matters. First, if the upper range of estimates is correct, then vertical transport in the middle atmosphere must be considerably faster than generally believed; whereas if the lower range is correct, then our understanding of dust evolution in the solar system, and transport from the middle atmosphere to the surface, will need substantial revision. Second, cosmic dust particles enter the atmosphere at high speeds and undergo significant ablation. The resulting metals injected into the atmosphere are involved in a diverse range of phenomena, including: the formation of layers of metal atoms and ions; the nucleation of noctilucent clouds, which are a sensitive marker of climate change; impacts on stratospheric aerosols and O3 chemistry, which need to be considered against the background of a cooling stratosphere and geo-engineering plans to increase sulphate aerosol; and fertilization of the ocean with bio-available Fe, which has potential climate feedbacks.

  18. Cosmic dust in the earth's atmosphere.

    PubMed

    Plane, John M C

    2012-10-01

    This review discusses the magnitude of the cosmic dust input into the earth's atmosphere, and the resulting impacts from around 100 km to the earth's surface. Zodiacal cloud observations and measurements made with a spaceborne dust detector indicate a daily mass input of interplanetary dust particles ranging from 100 to 300 tonnes, which is in agreement with the accumulation rates of cosmic-enriched elements (Ir, Pt, Os and super-paramagnetic Fe) in polar ice cores and deep-sea sediments. In contrast, measurements in the middle atmosphere - by radar, lidar, high-flying aircraft and satellite remote sensing - indicate that the input is between 5 and 50 tonnes per day. There are two reasons why this huge discrepancy matters. First, if the upper range of estimates is correct, then vertical transport in the middle atmosphere must be considerably faster than generally believed; whereas if the lower range is correct, then our understanding of dust evolution in the solar system, and transport from the middle atmosphere to the surface, will need substantial revision. Second, cosmic dust particles enter the atmosphere at high speeds and undergo significant ablation. The resulting metals injected into the atmosphere are involved in a diverse range of phenomena, including: the formation of layers of metal atoms and ions; the nucleation of noctilucent clouds, which are a sensitive marker of climate change; impacts on stratospheric aerosols and O(3) chemistry, which need to be considered against the background of a cooling stratosphere and geo-engineering plans to increase sulphate aerosol; and fertilization of the ocean with bio-available Fe, which has potential climate feedbacks. PMID:22678029

  19. Comparing Earth and Titan's atmospheric inventory

    NASA Astrophysics Data System (ADS)

    Bampasidis, Georgios; Coustenis, Athena; Solomonidou, Anezina; Moussas, Xenophon; Preka-Papadema, Panagiota

    2010-05-01

    Titan is currently the only confirmed exobiotic environment known to us. It is also perhaps the most intriguing object in our Solar System. Our understanding of Titan, and of the kronian system as a whole, has been greatly enhanced by the data returned by the Cassini/Huygens mission since 2004 and still operating on the spot. Thus, we know today that the thick atmosphere layer - covering the satellite's mysterious surface - is essentially made of nitrogen, with small amounts of methane and hydrogen. The combination among these mother molecules produces an exciting organic chemistry in Titan's atmosphere, with hydrocarbons and nitriles (one of the latter, HCN, is a prebiotic molecule). The organic chemistry, climate conditions, meteorology, methane cycle and other aspects of the surface make Titan an extremely important astrobiological place. We will summarize our current understanding of the analogues between Titan and Earth's atmospheres focusing on some compositional and climatological issues. After the Cassini/Huygens mission, there will remain several unanswered questions on the astrobiological aspects of the satellite that will require a future mission with an optimized orbital tour, specific in situ elements and advanced instrumentation, such as the Titan Saturn System Mission (Coustenis et al, 2009; Reh et al., 2009) studied in 2008. The TSSM orbiter with hi-resolution imagers and IR spectrometers onboard and the TSSM Montgolfier with an aerosol analyser and a meteorology package aboard will deeply investigate the Titan organic factory and its atmospheric diversity by performing long-term observations. Definitely, as Titan is a unique earth-like body in the solar system, the long experience of studying the terrestrial atmosphere gives us the tools to unveil the satellite's mysteries. On the other hand, Titan's science will significally contribute to the Earth's atmospheric knowledge, its evolution and chemistry and to the origin of life, as it certainly

  20. Chemistry of Earth's Putative Steam Atmosphere

    NASA Astrophysics Data System (ADS)

    Fegley, B.; Schaefer, L.

    2007-12-01

    The concept of a steam atmosphere generated by impact devolatilization of planetesimals accreted during Earth's formation is over 20 years old (Matsui and Abe, 1986; Lange and Ahrens, 1982). Surprisingly, with the possible exception of a few qualitative remarks, no one has critically assessed this scenario. We use thermochemical equilibrium and, where relevant, thermochemical kinetic calculations to model the chemistry of the "steam" atmosphere produced by impact volatilization of different types of accreting material. We present results for our nominal conditions (1500 K, total P = 100 bar). We also studied the effects of variable temperature and total pressure. The composition of the accreting material is modeled using average compositions of the Orgueil CI chondrite, the Murchison CM2 chondrite, the Allende CV3 chondrite, average ordinary (H, L, LL) chondrites, and average enstatite (EH, EL) chondrites. The major gases released from CI and CM chondritic material are H2O, CO2, H2, H2S, CO, CH4, and SO2 in decreasing order of abundance. About 10% of the atmosphere is CO2. The major gases released from CV chondritic material are CO2, H2O, CO, H2, and SO2 in decreasing order of abundance. About 20% of the total atmosphere is steam. The major gases released from average ordinary chondritic material are H2, CO, H2O, CO2, CH4, H2S, and N2 in decreasing order of abundance. The "steam" atmosphere is predominantly H2 + CO with steam being about 10% of the total atmosphere. The major gases released from EH chondritic material are H2, CO, H2O, CO2, N2, and CH4 in decreasing order of abundance. The "steam" atmosphere is predominantly H2 + CO with about 10% of the total atmosphere as steam. This work was supported by the NASA Astrobiology and Origins Programs.

  1. First Super-Earth Atmosphere Analysed

    NASA Astrophysics Data System (ADS)

    2010-12-01

    The atmosphere around a super-Earth exoplanet has been analysed for the first time by an international team of astronomers using ESO's Very Large Telescope. The planet, which is known as GJ 1214b, was studied as it passed in front of its parent star and some of the starlight passed through the planet's atmosphere. We now know that the atmosphere is either mostly water in the form of steam or is dominated by thick clouds or hazes. The results will appear in the 2 December 2010 issue of the journal Nature. The planet GJ 1214b was confirmed in 2009 using the HARPS instrument on ESO's 3.6-metre telescope in Chile (eso0950) [1]. Initial findings suggested that this planet had an atmosphere, which has now been confirmed and studied in detail by an international team of astronomers, led by Jacob Bean (Harvard-Smithsonian Center for Astrophysics), using the FORS instrument on ESO's Very Large Telescope. "This is the first super-Earth to have its atmosphere analysed. We've reached a real milestone on the road toward characterising these worlds," said Bean. GJ 1214b has a radius of about 2.6 times that of the Earth and is about 6.5 times as massive, putting it squarely into the class of exoplanets known as super-Earths. Its host star lies about 40 light-years from Earth in the constellation of Ophiuchus (the Serpent Bearer). It is a faint star [2], but it is also small, which means that the size of the planet is large compared to the stellar disc, making it relatively easy to study [3]. The planet travels across the disc of its parent star once every 38 hours as it orbits at a distance of only two million kilometres: about seventy times closer than the Earth orbits the Sun. To study the atmosphere, the team observed the light coming from the star as the planet passed in front of it [4]. During these transits, some of the starlight passes through the planet's atmosphere and, depending on the chemical composition and weather on the planet, specific wavelengths of light are

  2. Atmospheric heat engines on earth and Mars

    NASA Astrophysics Data System (ADS)

    Philip, J. R.

    1987-06-01

    The character of the earth's atmospheric heat engine depends, inter alia, on the relatively tight linkage between surface fluxes of energy and of H2O. On Mars, on the other hand, H2O-based latent heat fluxes are only a trivial fraction of total surface energy fluxes, and the dominant component of the working fluid is CO2. These considerations are made quantitative through evaluation of Lambda, the equivalent temperature excess at the surface for a particular component of the working fluid. The very different values (and latitudinal distribution) of Lambda on the two planets signalize vividly their different meteorology. Preliminary study of the climatology of Lambda on earth brings out, in particular, the tightness of the H2O-energy linkage in the tropics.

  3. Dynamic model of the Earth's upper atmosphere

    NASA Technical Reports Server (NTRS)

    Slowey, J. W.

    1984-01-01

    An initial modification to the MSF/J70 Thermospheric Model, in which the variations due to sudden geomagnetic disturbances upon the Earth's upper atmospheric density structure were modeled is presented. This dynamic model of the geomagnetic variation included is an improved version of one which SAO developed from the analysis of the ESRO 4 mass spectrometer data that was incorporated in the Jacchia 1977 model. The variation with geomagnetic local time as well as with geomagnetic latitude are included, and also the effects due to disturbance of the temperature profiles in the region of energy deposition.

  4. NASA Now: Earth’s Atmosphere: Earth Science Week

    NASA Video Gallery

    Dr. Kenneth Pickering talks about the composition of Earth’s atmosphere, how it protects life on Earth, and how it is interconnected with the Earth system. Pickering discusses findings from the D...

  5. NASA Now Minute: Earth’s Atmosphere: Earth Science Week

    NASA Video Gallery

    Dr. Kenneth Pickering talks about the composition of Earth’s atmosphere,how it protects life on Earth, and how it is interconnected with theEarth system. Pickering discusses findings from the D...

  6. Evolution of Earth&'s Atmosphere and Climate

    NASA Astrophysics Data System (ADS)

    Kasting, J. F.

    2004-12-01

    Earth's climate prior to 2.5 Ga seems to have been, if anything, warmer than today (1,2), despite the faintness of the young Sun (3). The idea that the young Sun was 25-30 percent less bright has been bolstered by data on mass loss from young, solar-type stars (4). Sagan and Mullen (1) suggested many years ago that the warming required to offset low solar luminosity was provided by high concentrations of reduced greenhouse gases. Ammonia has since been shown to be photochemically unstable in low-O2 atmospheres (5), but methane is a viable candidate. Methane photolyzes only at wavelengths shorter than 145 nm, so it is long-lived in the absence of O2 and O3. Furthermore, it is produced by anaerobic bacteria (methanogens) that are thought to have evolved early in Earth history (6). A biological methane flux comparable to today's flux, ~500 Tg CH4/yr, could have been generated by methanogens living in an anaerobic early ocean and sediments (7). This flux should have increased once oxygenic photosynthesis evolved because of increased production and recycling of organic matter (8). An Archean methane flux equal to today's flux could have generated atmospheric CH4 concentrations in excess of 1000 ppmv (9). This, in turn, could have provided 30 degrees or more of greenhouse warming (10) enough to have kept the early Earth warm even if atmospheric CO2 was no higher than today. All of this does not imply that CO2 concentrations must have been low throughout the Archean. Indeed, siderite-coated stream pebbles imply that pCO2 was greater than 2.5,e10-3 bar, or ~7 times present, at 3.2 Ga (11). Atmospheric CO2 could have been much higher than this if the continents had formed slowly (12) and/or if subduction of carbonates was inhibited (13). The rise in O2 at ~2.3 Ga (14,15) brought an end to the methane greenhouse and may have triggered the Huronian glaciation (10). Although methane concentrations declined with the rise of O2, they may still have remained much higher than

  7. New Data for Early Earth Atmospheric Modelling

    NASA Astrophysics Data System (ADS)

    Blackie, D.; Stark, G.; Lyons, J. R.; Pickering, J.; Smith, P. L.; Thorne, A.

    2010-12-01

    The timing of the oxygenation of the Earth’s atmosphere is a central issue in understanding the Earth’s paleoclimate. The discovery of mass-independent fractionation (MIF) of sulphur isotopes deposited within Archean and Paleoproterozoic rock samples (> 2.4 Gyrs) and the transition to mass-dependent fractionation found in younger samples, could provide a marker for the rise in oxygen concentrations in the Earth’s atmosphere [1]. Laboratory experiments [2; 3] suggest isotopic self shielding during gas phase photolysis of SO2 present at wavelengths shorter than 220 nm as the dominant mechanism for MIF. The UV absorption of SO2 is dominated by the C1B2-X1A1 electronic system which comprises strong vibrational bands extending from 170 - 230 nm. Within an atmosphere consisting of low O2 and O3 concentrations, such as that predicted for the early Earth, UV radiation would penetrate deep into the ancient Earth’s atmosphere in the 180 - 220 nm range driving the photolysis of SO2. We have conducted the first ever high resolution measurements of the photo absorption cross sections of several isotopologues of SO2, namely 32SO2, 33SO2, 34SO2 and 36SO2, using the Imperial College UV Fourier transform spectrometer [4] which is ideal for high resolution, broad-band, VIS/UV measurements. The cross sections are being measured at Imperial College at initial resolutions of 1.0 cm-1 which will be increased to resolutions < 0.5 cm-1 for inclusion in photochemical models of the early Earth’s atmosphere in order to more reliably interpret the sulphur isotope ratios found in ancient rock samples [5]. For discussion and interpretation of the photochemical models see the abstract by Lyons et al.(this meeting). References [1] J. Farquhar and B.A. Wing. Earth and Planetary Science Letters, 213:1-13, 2003. [2] J. Farquhar, J. Savarino, S. Airieau, and M.H Thiemens. Journal of Geophysical Research,106:32829-32839, 2001. [3] A. Pen and R. N. Clayton.Geochimica et Cosmochimica Acta

  8. Atmospheric breakup of a small comet in the Earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Teterev, A. V.; Misychenko, N. I.; Rudak, L. V.; Romanov, G. S.; Smetannikov, A. S.; Nemchinov, I. V.

    1993-01-01

    The aerodynamic stresses can lead to the deformation and even to destruction of the meteoroids during their flight through the atmosphere. The pressure at the blunt nose of the cosmic body moving at very high speed through the dense layers of the atmosphere may be much larger than the tensile or the compressive strength of the body. So the usage of the hydrodynamics theory is validated. The estimates show that the transverse velocity of the substance of the body U is of the order of (rho(sub a)/rho(sub o))(sup 1/2)V where V is the velocity of the body and rho(sub o) is its density, rho(sub a) is the density of the atmosphere. The separation of the fragments is larger than the diameter of the body D if D is less than D(sub c) = 2H(square root of rho(sub a)/rho(sub o)), where H is the characteristic scale of the atmosphere. For an icy body one obtains U = 1/30(V) and critical diameter D(sub C) = 500 m. The process of the disintegration of the body is still not fully understood and so one can use the numerical simulation to investigate it. Such simulations where conducted for the Venusian atmosphere and the gaseous equation of state of the body was used. For the Earth atmosphere for the velocity V = 50 km/s the pressure at the blunt nose of the body is 25 kbar, and is of the order of bulk modulus of compressibility of the water or ice. The realistic EOS of water in tabular form was used. It was assumed that the initial shape of the body was spherical and the initial diameter D(sub o) of the body is 200 m and so it is smaller than the critical diameter D(sub C). The initial kinetic energy of the icy body is equivalent to the energy of the explosion 1200 Mt of TNT. The results of the simulation of the deformation of the body during its vertical flight through the atmosphere and during its impact into the ocean are presented.

  9. Simulation of ablation in Earth atmospheric entry

    NASA Technical Reports Server (NTRS)

    Keenan, James A.; Candler, Graham V.

    1993-01-01

    The process of ablation for Earth atmospheric entry is simulated using a computational approach that allows thermo-chemical nonequilibrium of the flow field and ablation gases. The heat pulse into the heat shield is modeled. The flowfield and graphite heat shield are coupled through surface mass and energy balances. The surface thermochemistry involves the oxidation of graphite and allows for catalytic recombination of diatomic oxygen. Steady-state simulations are performed on a one meter nose radius sphere at an altitude of 65/km and at freestream velocities of 8 km/s and 10 km/s. A transient simulation is performed at 65 km altitude and a freestream velocity of 10 km/s.

  10. Extraterrestrial matter in the Earth atmosphere

    NASA Astrophysics Data System (ADS)

    Popova, Olga

    The Sub-Millimetre Radiometer (SMR) on board the Odin satellite, launched in February 2001, observes thermal emissions of stratospheric nitric oxide (NO) at the Earth limb in a band centred at 551.7GHz. As member of the NOx family, this species plays an important role in stratospheric ozone chemistry. At high altitudes in the thermosphere, NO is formed when N2 is dissociated by solar radiation and through energetic particle precipitation (e.g. auroral activity). Its spatio-temporal distribution is influenced by the global meridional circulation, in particular during polar night when the lifetime of NOx species is long enough that downward transported NOx can contribute to the NOy budget in the mesosphere and stratosphere. Global measurements of NO were performed by Odin/SMR on approximately one observation day per month from October 2003 to April 2007 and on a nearly weekly basis thereafter. This presentation focuses on a detailed description of the characteristics of the Odin observations. The derived Odin NO climatology is then analysed in relation to observed variability of middle atmospheric transport and solar radiation. Odin is a Swedish-led satellite project funded jointly by Sweden (SNSB), Canada (CSA), Fin-land (TEKES), and France (CNES), with support by the 3rd party mission programme of the European Space Agency (ESA).

  11. Interferometric Characterization of the Earth's Atmosphere from Lagrange Point 2

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Part of the NASA plans for future Earth-Science missions calls for observations using novel vantage points that can produce science products otherwise unobtainable. Observations of the Earth from the Lagrange-2 point, L-2, (1.5 million kilometers behind the Earth on the Earth-Sun line) affords a unique vantage point for atmospheric science. Special observation of the Earth's atmosphere using solar occultation techniques in the near infrared (1 to 4 microns) provides one of the most accurate method of passively sensing altitude profiles of the major species (CO2, O3, O2, CH4, H2O, N2O). In addition to observation of the Earth's atmosphere, it will be possible to observe a portion of the solar disk at moderate spatial resolution without interference from the Earth.

  12. Atmospheric attenuation relative to earth-viewing orbital sensors. [atmospheric moisture effects on microwaves

    NASA Technical Reports Server (NTRS)

    Brown, S. C.; Jayroe, R. R., Jr.

    1973-01-01

    Earth viewing space missions offer exciting new possibilities in several earth resources disciplines - geography, hydrology, agriculture, geology, and oceanography, to name a few. A most useful tool in planning experiments and applying space technology to earth observation is a statistical description of atmospheric parameters. Four dimensional atmospheric models and a world wide cloud model are used to produce atmospheric attenuation models to predict degradation effects for all classes of sensors for application to earth sensing experiments from spaceborne platforms. To insure maximum utility and application of these products, the development of an interaction model of microwave energy and atmospheric variables provides a complete description of the effects of atmospheric moisture upon microwaves.

  13. Atmospheric effects on measurements of distance to Earth artificial satellites

    NASA Astrophysics Data System (ADS)

    Kablak, N.; Klimyk, V.; Shvalagin, I.; Kablak, U.

    2005-06-01

    This paper is devoted to the problem of accuracy increasing in allowing for Earth's atmosphere influences on results of daily ranging observations of the Earth artificial satellites (ASE). Atmosphere delays and their spatial-timely variations for spherical-symmetrical and nonspherical models of atmosphere were determined radiosounding data gathered during a year in Ukraine region using, developed valuing and analysis of models reductions to over of atmosphere, which recommended of IERS for processing distance-ranging observations of the Earth artificial satellites. Investigated and improved models of reductions to over of the atmosphere on the basis of discovered regional and local peculiarity's of influence atmosphere on the laser and radio ranging observations of the Earth artificial satellites.

  14. Global Change in Earth's Atmosphere: Natural and Anthropogenic Factors

    NASA Astrophysics Data System (ADS)

    Lean, J.

    2013-12-01

    To what extent is human activity, such as the emission of carbon dioxide and other 'greenhouse' gases, influencing Earth's atmosphere, compared with natural variations driven by, for example, the Sun or volcanoes? Why has Earth's surface warmed barely, if at all, in the last decade? Why is the atmosphere at just 20 km above the surface cooling instead of warming? When - and will - the ozone layer recover from its two-decade decline due to chlorofluorocarbon depletion? Natural and anthropogenic factors are changing Earth's atmosphere, each with distinct temporal, geographical and altitudinal signatures. Increasing greenhouse gases, for example, warm the surface but cool the stratosphere and upper atmosphere. Aerosols injected into the stratosphere during a volcanic eruption warm the stratosphere but cool the surface. Increases in the Sun's brightness warm Earth's atmosphere, throughout. This talk will quantify and compare a variety of natural and human influences on the Earth's atmosphere, extracted statistically from multiple datasets with the goal of understanding how and why Earth's atmosphere is changing. The extent to which responses to natural influences are presently masking or exacerbating ongoing responses to human activity is examined. Scenarios for future levels of anthropogenic gases and solar activity are then used to speculate how Earth's atmosphere might evolve in future decades, according to both statistical models of the databases and physical general circulation models.

  15. Telescope Formation at L2 for Observing Earth's Atmosphere

    NASA Technical Reports Server (NTRS)

    Mettler, Edward; Acikmese, Behcet; Breckenridge, William; Macenka, Steven; Hein, Randall; Tubbs, Eldred

    2007-01-01

    Two documents describe a proposed Earth-atmosphere observatory to orbit the Sun at the Sun-Earth L2 Lagrange point -- a point of unstable equilibrium in the shadow of the Earth, about 1.5 million km from the Earth along an outward projection of the Earth-Sun axis. The observatory would comprise two spacecraft flying in precision formation: (1) a primary-aperture spacecraft, from which would be deployed a 25-m diameter membrane primary mirror aimed at the Earth, and (2) a secondary-telescope spacecraft at the focal plane of the primary mirror, 125-m distant along the axis towards the Earth. The secondary telescope would be aimed at the primary mirror and slowly rotated to scan the focused annular image of the visible illuminated portion of the Earth's atmosphere during continuous occultation of the Sun.

  16. Atmospheres and evolution. [of microbial life on earth

    NASA Technical Reports Server (NTRS)

    Margulis, L.; Lovelock, J. E.

    1981-01-01

    Studies concerning the regulation of the earth atmosphere and the relation of atmospheric changes to the evolution of microbial life are reviewed. The improbable nature of the composition of the earth atmosphere in light of the atmospheric compositions of Mars and Venus and equilibrium considerations is pointed out, and evidence for the existence of microbial (procaryotic) life on earth as far back as 3.5 billion years ago is presented. The emergence of eucaryotic life in the Phanerozoic due to evolving symbioses between different procaryotic species is discussed with examples given of present-day symbiotic relationships between bacteria and eucaryotes. The idea that atmospheric gases are kept in balance mainly by the actions of bacterial cells is then considered, and it is argued that species diversity is necessary for the maintenance and origin of life on earth in its present form.

  17. ATMOS: Long term atmospheric measurements for mission to planet Earth

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A long-term, space-based measurement program, together with continued balloon and aircraft-borne investigations, is essential to monitor the predicted effects in the atmosphere, to determine to what extent the concentration measurements agree with current models of stratospheric chemistry, and to determine the condition of the ozone layer. The Atmospheric Trace Molecule Spectroscopy (ATMOS) Experiment is currently making comprehensive, global measurements of Earth's atmosphere as part of the Atmospheric Laboratory for Applications and Science (ATLAS) program on the Space Shuttle. Part of NASA's Mission to Planet Earth, ATLAS is a continuing series of missions to study Earth and the Sun and provide a more fundamental understanding of the solar influences on Earth's atmosphere. The ATMOS program, instruments, and science results are presented.

  18. STS-39 Earth observation of Earth's limb at sunset shows atmospheric layers

    NASA Technical Reports Server (NTRS)

    1991-01-01

    STS-39 Earth observation taken aboard Discovery, Orbiter Vehicle (OV) 103, shows the Earth's limb at sunset with numerous atmospheric scattering layers highlighted. The layers consist of fine particles suspended in very stable layers of the atmosphere. The layers act as a prism for the sunlight.

  19. ON THE STABILITY OF SUPER-EARTH ATMOSPHERES

    SciTech Connect

    Heng, Kevin; Kopparla, Pushkar

    2012-07-20

    We investigate the stability of super-Earth atmospheres around M stars using a seven-parameter, analytical framework. We construct stability diagrams in the parameter space of exoplanetary radius versus semimajor axis and elucidate the regions in which the atmospheres are stable against the condensation of their major constituents, out of the gas phase, on their permanent nightside hemispheres. We find that super-Earth atmospheres that are nitrogen-dominated (Earth-like) occupy a smaller region of allowed parameter space, compared to hydrogen-dominated atmospheres, because of the dual effects of diminished advection and enhanced radiative cooling. Furthermore, some super-Earths which reside within the habitable zones of M stars may not possess stable atmospheres, depending on the mean molecular weight and infrared photospheric pressure of their atmospheres. We apply our stability diagrams to GJ 436b and GJ 1214b, and demonstrate that atmospheric compositions with high mean molecular weights are disfavored if these exoplanets possess solid surfaces and shallow atmospheres. Finally, we construct stability diagrams tailored to the Kepler data set, for G and K stars, and predict that about half of the exoplanet candidates are expected to harbor stable atmospheres if Earth-like conditions are assumed. We include 55 Cancri e and CoRoT-7b in our stability diagram for G stars.

  20. Catalytic processes in the atmospheres of Earth and venus.

    PubMed

    Demore, W B; Yung, Y L

    1982-09-24

    Photochemical processes in planetary atmospheres are strongly influenced by catalytic effects of minor constituents. Catalytic cycles in the atmospheres of Earth and Venus are closely related. For example, chlorine oxides (CIOx) act as catalysts in the two atmospheres. On Earth, they serve to convert odd oxygen (atomic oxygen and ozone) to molecular oxygen. On Venus they have a similar effect, but in addition they accelerate the reactions of atomic and molecular oxygen with carbon monoxide. The latter process occurs by a unique combination of CIOx catalysis and sulfur dioxide photosensitization. The mechanism provides an explanation for the very low extent of carbon dioxide decomposition by sunlight in the Venus atmosphere. PMID:17837628

  1. Crossing the Boundaries in Planetary Atmospheres - From Earth to Exoplanets

    NASA Technical Reports Server (NTRS)

    Simon-Miller, Amy A.; Genio, Anthony Del

    2013-01-01

    The past decade has been an especially exciting time to study atmospheres, with a renaissance in fundamental studies of Earths general circulation and hydrological cycle, stimulated by questions about past climates and the urgency of projecting the future impacts of humankinds activities. Long-term spacecraft and Earth-based observation of solar system planets have now reinvigorated the study of comparative planetary climatology. The explosion in discoveries of planets outside our solar system has made atmospheric science integral to understanding the diversity of our solar system and the potential habitability of planets outside it. Thus, the AGU Chapman Conference Crossing the Boundaries in Planetary Atmospheres From Earth to Exoplanets, held in Annapolis, MD from June 24-27, 2013 gathered Earth, solar system, and exoplanet scientists to share experiences, insights, and challenges from their individual disciplines, and discuss areas in which thinking broadly might enhance our fundamental understanding of how atmospheres work.

  2. Earth Global Reference Atmospheric Model 2007 (Earth-GRAM07)

    NASA Technical Reports Server (NTRS)

    Leslie, Fred W.; Justus, C. G.

    2008-01-01

    GRAM is a Fortran software package that can run on a variety of platforms including PC's. GRAM provides values of atmospheric quantities such as temperature, pressure, density, winds, constituents, etc. GRAM99 covers all global locations, all months, and heights from the surface to approx. 1000 km). Dispersions (perturbations) of these parameters are also provided and are spatially and temporally correlated. GRAM can be run in a stand-alone mode or called as a subroutine from a trajectory program. GRAM07 is diagnostic, not prognostic (i.e., it describes the atmosphere, but it does not forecast). The source code is distributed free-of-charge to eligible recipients.

  3. Space Science in Action: Earth's Atmosphere [Videotape].

    ERIC Educational Resources Information Center

    1999

    In this videotape recording, students learn about the layers of the atmosphere and why each is important to the survival of life on the planet. Students discover why the atmosphere is responsible for weather and see how special aircraft actually fly into hurricanes. Students build their own working barometer in a hands-on activity. Contents…

  4. Energetic particle influences in Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Aplin, Karen; Harrison, R. Giles; Nicoll, Keri; Rycroft, Michael; Briggs, Aaron

    2016-04-01

    Energetic particles from outer space, known as galactic cosmic rays, constantly ionise the entire atmosphere. During strong solar storms, solar energetic particles can also reach the troposphere and enhance ionisation. Atmospheric ionisation generates cluster ions. These facilitate current flow in the global electric circuit, which arises from charge separation in thunderstorms driven by meteorological processes. Energetic particles, whether solar or galactic in origin, may influence the troposphere and stratosphere through a range of different mechanisms, each probably contributing a small amount. Some of the suggested processes potentially acting over a wide spatial area in the troposphere include enhanced scavenging of charged aerosol particles, modification of droplet or droplet-droplet behavior by charging, and the direct absorption of infra-red radiation by the bending and stretching of hydrogen bonds inside atmospheric cluster-ions. As well as reviewing the proposed mechanisms by which energetic particles modulate atmospheric properties, we will also discuss new instrumentation for measurement of energetic particles in the atmosphere.

  5. Atmospherics: A Look at the Earth's Airy Shell.

    ERIC Educational Resources Information Center

    Byalko, A. V.

    1991-01-01

    Describes differences in the composition, pressure, and temperature at distinct altitudes of the Earth's atmosphere from the point of view of physical laws. Discusses the genesis and importance of ozone, thermal radiation and the "layer cake" arrangement of the atmosphere, and solar energy in connection with thermal equilibrium. (JJK)

  6. Expedition Seven Takes Breathtaking Photo of Earth's Atmosphere

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This Expedition Seven image, taken while aboard the International Space Station (ISS), shows the limb of the Earth at the bottom transitioning into the orange-colored stratosphere, the lowest and most dense portion of the Earth's atmosphere. The troposphere ends abruptly at the tropopause, which appears in the image as the sharp boundary between the orange- and blue-colored atmosphere. The silvery blue noctilucent clouds extend far above the Earth's troposphere. The silver of the setting moon is visible at upper right.

  7. CHEMISTRY OF SILICATE ATMOSPHERES OF EVAPORATING SUPER-EARTHS

    SciTech Connect

    Schaefer, Laura; Fegley, Bruce E-mail: bfegley@levee.wustl.ed

    2009-10-01

    We model the formation of silicate atmospheres on hot volatile-free super-Earths. Our calculations assume that all volatile elements such as H, C, N, S, and Cl have been lost from the planet. We find that the atmospheres are composed primarily of Na, O{sub 2}, O, and SiO gas, in order of decreasing abundance. The atmospheric composition may be altered by fractional vaporization, cloud condensation, photoionization, and reaction with any residual volatile elements remaining in the atmosphere. Cloud condensation reduces the abundance of all elements in the atmosphere except Na and K. We speculate that large Na and K clouds such as those observed around Mercury and Io may surround hot super-Earths. These clouds would occult much larger fractions of the parent star than a closely bound atmosphere, and may be observable through currently available methods.

  8. The rise of oxygen in Earth's early ocean and atmosphere.

    PubMed

    Lyons, Timothy W; Reinhard, Christopher T; Planavsky, Noah J

    2014-02-20

    The rapid increase of carbon dioxide concentration in Earth's modern atmosphere is a matter of major concern. But for the atmosphere of roughly two-and-half billion years ago, interest centres on a different gas: free oxygen (O2) spawned by early biological production. The initial increase of O2 in the atmosphere, its delayed build-up in the ocean, its increase to near-modern levels in the sea and air two billion years later, and its cause-and-effect relationship with life are among the most compelling stories in Earth's history. PMID:24553238

  9. The chemical composition and climatology of the earth's early atmosphere

    NASA Technical Reports Server (NTRS)

    Henderson-Sellers, A.

    1983-01-01

    The earth's climate as it relates to the evolution of life is discussed.. Seven fundamental characteristics of the early evolutionary environment are examined, including a carbon dioxide and water vapor atmosphere, atmospheric mass between 500 and 1000 mb, a global hydrosphere, lowered solar luminosity, hospitable average global temperatures, a convectively active atmosphere, and trace gases. The influence of the early earth's extensive hydrosphere on the origin of life is considered. The warming of that hydrosphere due to radiative fluxes and the greenhouse effect is examined, and the nature of the feedback between clouds and climate is addressed.

  10. Study of the Interaction of Micrometeoroids with Earth's Atmosphere

    NASA Astrophysics Data System (ADS)

    Briani, G.; Pupillo, G.; Aiello, S.; Pace, E.; Shore, S.; Passaro, A.

    Submillimetric micrometeoroids dominates the annual extraterrestrial mass flux toward the Earth. Indeed these bodies show an unexpected ability to survive the interaction with the terrestrial atmosphere. In this work it is suggested a new general numerical model for the micrometeoroids-atmosphere interaction: this is the first step of a more extended study \\citep{aiello} that includes also experiments for the next few years in laboratories as well in atmosphere (microsatellites or balloon-borne experiments).

  11. Propagation of sound through the Earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Meredith, R. W.; Becher, J.

    1983-01-01

    The data collected at a pressure of one atmosphere for the different temperatures and relative humidities of the air-water vapor mixtures is summarized. The dew point hygrometer used in these measurements did not give reliable results for dew points much above the ambient room temperature. For this reason measurements were not attempted at the higher temperatures and humidities. Viscous wall losses in the resonant tube at 0 C so dominate the molecular relaxation of nitrogen, in the air-water vapor mixture, that reliable data could not be obtained using the free decay method in a resonant tube at one atmosphere. In an effort to obtain viable data at these temperatures, measurements were performed at a pressure of 10 atmospheres. Since the molecular relaxation peak is proportional to the pressure and the viscous losses are proportional to the inverse square root of the pressure the peak height should be measurable at the higher pressure. The tradeoff here is that at 10 atmospheres; the highest relative humidity attainable is 10 percent. The data collected at 10 atmospheres is also summarized.

  12. Optical Instability of the Earth's Atmosphere

    NASA Technical Reports Server (NTRS)

    Kucherov, N. I. (Editor)

    1966-01-01

    The atmosphere is not stationary: it changes continuously and its optical properties are inherently unstable. This optical instability of the air medium is of considerable significance in various fields of research and observation where light transmission through the atmosphere plays a basic role. Under the category of optical instabilities we mainly have the different atmospheric perturbations whose integrated effect constitutes the astroclimate: these are image pulsation, scintillation, and the blurring of the diffraction disk. The artificial satellites and space probes collected a great amount of new data on the upper atmosphere and on the outer space environment. New interesting and important problems arose, which attracted the attention of many geophysicists and astronomers. This shift in the center of gravity of scientific interests and efforts is observed mainly among scientists specializing in atmospheric physics. Recently, scientific organizations engaged on optical instability research switched to astroclimatic topics. Twelve scientific organizations were represented at the Soviet astronomers have recently been charged with a very difficult and responsible task: to select suitable sites for the erection of new observatories, including an astrophysical observatory with the largest telescope in the USSR. A considerable number of research groups were dispatched into various areas of the Soviet Union, and many astronomical observatories took part in the astroclimatic survey. The work of these expeditions remains un-paralleled by any other country in the world. On the other hand, these researches aroused a definite interest in astroclimate in Soviet astronomical observatories. International astronomical circles pay an ever growing attention to the problems of astroclimate.

  13. Earth Global Reference Atmospheric Model (GRAM99): Short Course

    NASA Technical Reports Server (NTRS)

    Leslie, Fred W.; Justus, C. G.

    2007-01-01

    Earth-GRAM is a FORTRAN software package that can run on a variety of platforms including PC's. For any time and location in the Earth's atmosphere, Earth-GRAM provides values of atmospheric quantities such as temperature, pressure, density, winds, constituents, etc.. Dispersions (perturbations) of these parameters are also provided and have realistic correlations, means, and variances - useful for Monte Carlo analysis. Earth-GRAM is driven by observations including a tropospheric database available from the National Climatic Data Center. Although Earth-GRAM can be run in a "stand-alone" mode, many users incorporate it into their trajectory codes. The source code is distributed free-of-charge to eligible recipients.

  14. Evolution of a steam atmosphere during earth's accretion

    NASA Astrophysics Data System (ADS)

    Zahnle, K. J.; Kasting, J. F.; Pollack, J. B.

    1988-04-01

    The evolution of an impact-generated steam atmosphere around an accreting earth is presently modeled under the assumption of Safronov (1978) accretion, in a scheme that encompasses the degassing of planetesimals on impact, thermal blanketing by the steam atmosphere, surface-to-interior water exchange, the shock heating and convective cooling of the earth's interior, and hydrogen escape due both to solar EUV-powered planetary wind and impact erosion. The model yields four distinct classes of impact-generated atmospheres: the first, on which emphasis is placed, has as its salient feature a molten surface that is maintained by the opacity of a massive water vapor atmosphere; the second occurs when the EUV-limited escape exceeds the impact degassing rate, while the third is dominated by impact erosion and the fourth is characterized by an atmosphere more massive than any thus far encountered.

  15. Impacts and atmospheric erosion on the early Earth

    NASA Technical Reports Server (NTRS)

    Vickery, A. M.

    1991-01-01

    It was suggested that heating and/or vaporization of accreting carbonaceous-chondrite-type planetestimals could result in the release of their volatile components. Modeling of this process strongly suggests that substantial atmospheres/hydrospheres could develop this way. During most of the accretionary process, impact velocities generally differed from the escape velocity of the growing proto-planet because most of the collisions were between bodies in nearly matching orbits. Toward the end of accretion, however, collisions were rarer but more energetic, involving large planetestimals and higher impact velocities. Such impacts result in a net loss of atmosphere from a planet, and the cumulative effect impacts during the period of heavy bombardment might have dramatically depleted the original atmospheres. Models developed to study atmospheric erosion by impacts on Mars and the interaction of the vapor plume produced by KT impactor on Earth are applied to the case of the evolution of Earth's atmosphere.

  16. Evolution of a steam atmosphere during earth's accretion

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin J.; Kasting, James F.; Pollack, James B.

    1988-01-01

    The evolution of an impact-generated steam atmosphere around an accreting earth is presently modeled under the assumption of Safronov (1978) accretion, in a scheme that encompasses the degassing of planetesimals on impact, thermal blanketing by the steam atmosphere, surface-to-interior water exchange, the shock heating and convective cooling of the earth's interior, and hydrogen escape due both to solar EUV-powered planetary wind and impact erosion. The model yields four distinct classes of impact-generated atmospheres: the first, on which emphasis is placed, has as its salient feature a molten surface that is maintained by the opacity of a massive water vapor atmosphere; the second occurs when the EUV-limited escape exceeds the impact degassing rate, while the third is dominated by impact erosion and the fourth is characterized by an atmosphere more massive than any thus far encountered.

  17. Clouds in Super-Earth Atmospheres: Chemical Equilibrium Calculations

    NASA Astrophysics Data System (ADS)

    Mbarek, Rostom; Kempton, Eliza M.-R.

    2016-08-01

    Recent studies have unequivocally proven the existence of clouds in super-Earth atmospheres. Here we provide a theoretical context for the formation of super-Earth clouds by determining which condensates are likely to form under the assumption of chemical equilibrium. We study super-Earth atmospheres of diverse bulk composition, which are assumed to form by outgassing from a solid core of chondritic material, following Schaefer & Fegley. The super-Earth atmospheres that we study arise from planetary cores made up of individual types of chondritic meteorites. They range from highly reducing to oxidizing and have carbon to oxygen (C:O) ratios that are both sub-solar and super-solar, thereby spanning a range of atmospheric composition that is appropriate for low-mass exoplanets. Given the atomic makeup of these atmospheres, we minimize the global Gibbs free energy of formation for over 550 gases and condensates to obtain the molecular composition of the atmospheres over a temperature range of 350–3000 K. Clouds should form along the temperature–pressure boundaries where the condensed species appear in our calculation. We find that the composition of condensate clouds depends strongly on both the H:O and C:O ratios. For the super-Earth archetype GJ 1214b, KCl and ZnS are the primary cloud-forming condensates at solar composition, in agreement with previous work. However, for oxidizing atmospheres, K2SO4 and ZnO condensates are favored instead, and for carbon-rich atmospheres with super-solar C:O ratios, graphite clouds appear. For even hotter planets, clouds form from a wide variety of rock-forming and metallic species.

  18. The atmospheres of Venus, earth, and Mars - A critical comparison

    NASA Technical Reports Server (NTRS)

    Prinn, Ronald G.; Fegley, Bruce, Jr.

    1987-01-01

    The physical conditions and structures, chemical compositions, origins, and evolutions of the earth, Mars, and Venus atmospheres are compared, summarizing the results of recent theoretical and observational investigations. Data are compiled in extensive tables, graphs, and diagrams and characterized in detail. Consideration is given to the roles of chemical cycles and biology; global changes in atmospheric composition; the secondary origin of all three atmospheres; volatile retention by solid grains in the solar nebula; volatile degassing and atmosphere formation; and evolutionary processes, sources, cycles, and sinks.

  19. Clouds Composition in Super-Earth Atmospheres: Chemical Equilibrium Calculations

    NASA Astrophysics Data System (ADS)

    Kempton, Eliza M.-R.; Mbarek, Rostom

    2015-12-01

    Attempts to determine the composition of super-Earth atmospheres have so far been plagued by the presence of clouds. Yet the theoretical framework to understand these clouds is still in its infancy. For the super-Earth archetype GJ 1214b, KCl, Na2S, and ZnS have been proposed as condensates that would form under the condition of chemical equilibrium, if the planet’s atmosphere has a bulk composition near solar. Condensation chemistry calculations have not been presented for a wider range of atmospheric bulk composition that is to be expected for super-Earth exoplanets. Here we provide a theoretical context for the formation of super-Earth clouds in atmospheres of varied composition by determining which condensates are likely to form, under the assumption of chemical equilibrium. We model super-Earth atmospheres assuming they are formed by degassing of volatiles from a solid planetary core of chondritic material. Given the atomic makeup of these atmospheres, we minimize the global Gibbs free energy of over 550 gases and condensates to obtain the molecular composition of the atmospheres over a temperature range of 350-3,000 K. Clouds should form along the temperature-pressure boundaries where the condensed species appear in our calculations. The super-Earth atmospheres that we study range from highly reducing to oxidizing and have carbon to oxygen (C:O) ratios that are both sub-solar and super-solar, thereby spanning a diverse range of atmospheric composition that is appropriate for low-mass exoplanets. Some condensates appear across all of our models. However, the majority of condensed species appear only over specific ranges of H:O and C:O ratios. We find that for GJ 1214b, KCl is the primary cloud-forming condensate at solar composition, in agreement with previous work. However, for oxidizing atmospheres, where H:O is less than unity, K2SO4 clouds form instead. For carbon-rich atmospheres with super-solar C:O ratios, graphite clouds additionally appear. At

  20. VAPORIZATION OF THE EARTH: APPLICATION TO EXOPLANET ATMOSPHERES

    SciTech Connect

    Schaefer, Laura; Lodders, Katharina; Fegley, Bruce E-mail: lschaefer@cfa.harvard.edu E-mail: bfegley@wustl.edu

    2012-08-10

    Currently, there are about three dozen known super-Earths (M < 10 M{sub Circled-Plus }), of which eight are transiting planets suitable for atmospheric follow-up observations. Some of the planets are exposed to extreme temperatures as they orbit close to their host stars, e.g., CoRot-7b, and all of these planets have equilibrium temperatures significantly hotter than the Earth. Such planets can develop atmospheres through (partial) vaporization of their crustal and/or mantle silicates. We investigated the chemical equilibrium composition of such heated systems from 500 to 4000 K and total pressures from 10{sup -6} to 10{sup +2} bars. The major gases are H{sub 2}O and CO{sub 2} over broad temperature and pressure ranges, and Na, K, O{sub 2}, SiO, and O at high temperatures and low pressures. We discuss the differences in atmospheric composition arising from vaporization of SiO{sub 2}-rich (i.e., felsic) silicates (like Earth's continental crust) and MgO-, FeO-rich (i.e., mafic) silicates (like the bulk silicate Earth). The computational results will be useful in planning spectroscopic studies of the atmospheres of Earth-like exoplanets.

  1. Earth Global Reference Atmospheric Model 2007 (Earth-GRAM07) Applications for the NASA Constellation Program

    NASA Technical Reports Server (NTRS)

    Leslie, Fred W.; Justus, C. G.

    2008-01-01

    Engineering models of the atmosphere are used extensively by the aerospace community for design issues related to vehicle ascent and descent. The Earth Global Reference Atmosphere Model version 2007 (Earth-GRAM07) is the latest in this series and includes a number of new features. Like previous versions, Earth-GRAM07 provides both mean values and perturbations for density, temperature, pressure, and winds, as well as monthly- and geographically-varying trace constituent concentrations. From 0 km to 27 km, thermodynamics and winds are based on the National Oceanic and Atmospheric Administration Global Upper Air Climatic Atlas (GUACA) climatology. For altitudes between 20 km and 120 km, the model uses data from the Middle Atmosphere Program (MAP). Above 120 km, EarthGRAM07 now provides users with a choice of three thermosphere models: the Marshall Engineering Thermosphere (MET-2007) model; the Jacchia-Bowman 2006 thermosphere model (JB2006); and the Naval Research Labs Mass Spectrometer, Incoherent Scatter Radar Extended Model (NRL MSIS E-OO) with the associated Harmonic Wind Model (HWM-93). In place of these datasets, Earth-GRAM07 has the option of using the new 2006 revised Range Reference Atmosphere (RRA) data, the earlier (1983) RRA data, or the user may also provide their own data as an auxiliary profile. Refinements of the perturbation model are also discussed which include wind shears more similar to those observed at the Kennedy Space Center than the previous version Earth-GRAM99.

  2. Catalytic processes in the atmospheres of earth and Venus

    NASA Astrophysics Data System (ADS)

    Demore, W. B.; Yung, Y. L.

    1982-09-01

    Photochemical processes in planetary atmospheres are strongly influenced by catalytic effects of minor constituents. Catalytic cycles in the atmospheres of Earth and Venus are closely related. For example, chlorine oxides (ClOx) act as catalysts in the two atmospheres. On earth, they serve to convert odd oxygen (atomic oxygen and ozone) to molecular oxygen. On Venus they have a similar effect, but in addition they accelerate the reactions of atomic and molecular oxygen with carbon monoxide. The latter process occurs by a unique combination of ClOx catalysis and sulful dioxide photosensitization. The mechanism provides an explanation for the very low extent of carbon dioxide decomposition by sunlight in the Venus atmosphere.

  3. Catalytic processes in the atmospheres of earth and Venus

    NASA Technical Reports Server (NTRS)

    Demore, W. B.; Yung, Y. L.

    1982-01-01

    Photochemical processes in planetary atmospheres are strongly influenced by catalytic effects of minor constituents. Catalytic cycles in the atmospheres of Earth and Venus are closely related. For example, chlorine oxides (ClOx) act as catalysts in the two atmospheres. On earth, they serve to convert odd oxygen (atomic oxygen and ozone) to molecular oxygen. On Venus they have a similar effect, but in addition they accelerate the reactions of atomic and molecular oxygen with carbon monoxide. The latter process occurs by a unique combination of ClOx catalysis and sulful dioxide photosensitization. The mechanism provides an explanation for the very low extent of carbon dioxide decomposition by sunlight in the Venus atmosphere.

  4. Impact on the earth, ocean and atmosphere

    NASA Technical Reports Server (NTRS)

    Ahrens, Thomas J.; O'Keefe, John D.

    1987-01-01

    On the basis of finite-difference techniques, cratering flow calculations are used to obtain the spatial attenuation of shock pressure with radius along the impact axis for the impact of silicate rock and iron impactors on a silicate half-space at speeds of 5 to 45 km/sec. Upon impact of a 10 to 30 km diameter silicate or water object onto a 5 km deep ocean overlying a silicate half-space planet at 30 km/sec, it is found that from 12 to 15 percent of the incident energy is coupled into the water. The mass of atmosphere lost due to impacts of 1 to 5 km radius projectiles is calculated.

  5. COMPOSITIONS OF HOT SUPER-EARTH ATMOSPHERES: EXPLORING KEPLER CANDIDATES

    SciTech Connect

    Miguel, Y.; Kaltenegger, L.; Fegley, B.; Schaefer, L.

    2011-12-15

    This paper outlines a simple approach to evaluate the atmospheric composition of hot rocky planets by assuming different types of planetary composition and using corresponding model calculations. To explore hot atmospheres above 1000 K, we model the vaporization of silicate magma and estimate the range of atmospheric compositions according to the planet's radius and semi-major axis for the Kepler 2011 February data release. Our results show five atmospheric types for hot, rocky super-Earth atmospheres, strongly dependent on the initial composition and the planet's distance to the star. We provide a simple set of parameters that can be used to evaluate atmospheric compositions for current and future candidates provided by the Kepler mission and other searches.

  6. Water inventories on Earth and Mars: Clues to atmosphere formation

    NASA Technical Reports Server (NTRS)

    Carr, M. H.

    1992-01-01

    Water is distributed differently on Earth and on Mars and the differences may have implications for the accretion of the two planets and the formation of their atmospheres. The Earth's mantle appears to contain at least several times the water content of the Martian mantle even accounting for differences in plate tectonics. One explanation is that the Earth's surface melted during accretion, as a result of development of a steam atmosphere, thereby allowing impact-devolitalized water at the surface to dissolve into the Earth's interior. In contrast, because of Mars' smaller size and greater distance from the Sun, the Martian surface may not have melted, so that the devolatilized water could not dissolve into the surface. A second possibility is suggested by the siderophile elements in the Earth's mantle, which indicates the Earth acquired a volatile-rich veneer after the core formed. Mars may have acquired a late volatile-rich veneer, but it did not get folded into the interior as with the Earth, but instead remained as a water rich veneer. This perception of Mars with a wet surface but dry interior is consistent with our knowledge of Mars' geologic history.

  7. Lunar laser ranging and limits due to the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Currie, Douglas; Prochazka, Ivan

    2015-10-01

    The ultimate limits on high accuracy laser ranging to satellites from the ground appear to be caused by the effects of the earth's atmosphere. Other impediments in terms of lasers, timing equipment and calibration seem to be evolving to the point of providing very high accuracy. We shall address the role of the earth's atmosphere for lunar laser ranging. In the near future, the robotic deployment of next generation lunar laser retroreflectors is planned. With proper robotic deployment, these retroreflectors may support single photo-electron ranging accuracy at the 100 micron level or better. In particular, there are questions of the random and systematic delays and broadening of a very narrow laser pulse. Theoretical and experimental results will be discussed that address estimates of the magnitudes of these effects and the issue of precision vs. accuracy. These effects may be roughly divided into three domains: High frequency effects due to atmospheric turbulence, low frequency effects due to atmospheric "slopes" and atmospheric waves and tides and spectral dispersion of the narrow pulse. In conclusion, the route to better ranging through the earth's atmosphere appears to be more advance modeling of local meteorological effects, in a program that can be implemented at a reasonable cost.

  8. Passive ranging through the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Hasson, Victor H.; Dupuis, Christopher R.

    2002-02-01

    Many luminous sources provide continuous or quasi-continuous radiation at near IR and longer wavelengths. The radiation continuum serves as a source of background photons, which can be used for discrete line-of-site absorption measurements by-known atmospheric constituents. The intensity ratio is uniquely determined by the absorption coefficient and range, is independent of broadband attenuations and scattering. The absorption coefficients are known and/or can be accurately calculated for a wide range of practical viewing conditions (i.e., sensor height, viewing angle, etc.). Hence, the intensity ratio and/or integrated intensity ratio can be used to uniquely derive the range of the radiating source. Fabry-Perot interferometers can provide the high throughputs and resolving powers required in compact packages. The measurements and analyses show that ranging accuracies representing down to 1 - 2% of the total range should be achievable at stand-off ranges of upto hundreds of kilometers depending on the size of the collection optics, brightness of the source and available observation times. The paper will provide an overview of the patented Textron concepts, trade-offs associated with instrument resolving powers and hardware implementation issues.

  9. Earth's Mysterious Atmosphere: Atlas 1 Teacher's Guide with Activities.

    ERIC Educational Resources Information Center

    Essex Corp., Huntsville, AL.

    This atmospheric studies teacher's guide for use with middle school students blends lessons in chemistry, physics, and the life, earth, and space sciences in an attempt to accomplish the following: to nurture students' natural curiosity and excitement about science, mathematics, and technology; to encourage career exploration in science,…

  10. Biological modulation of planetary atmospheres: The early Earth scenario

    NASA Technical Reports Server (NTRS)

    Schidlowski, M.

    1985-01-01

    The establishment and subsequent evolution of life on Earth had a profound impact on the chemical regime at the planet's surface and its atmosphere. A thermodynamic gradient was imposed on near-surface environments that served as the driving force for a number on important geochemical transformations. An example is the redox imbalance between the modern atmosphere and the material of the Earth's crust. Current photochemical models predict extremely low partial pressures of oxygen in the Earth's prebiological atmosphere. There is widespread consensus that any large-scale oxygenation of the primitive atmosphere was contingent on the advent of biological (autotrophic) carbon fixation. It is suggested that photoautotrophy existed both as a biochemical process and as a geochemical agent since at least 3.8 Ga ago. Combining the stoichiometry of the photosynthesis reaction with a carbon isotope mass balance and current concepts for the evolution of the stationary sedimentary mass as a funion of time, it is possible to quantify, the accumulation of oxygen and its photosynthetic oxidation equivalents through Earth history.

  11. Earth orientation parameters: excitation by atmosphere, oceans and geomagnetic jerks

    NASA Astrophysics Data System (ADS)

    Vondrak, Jan; Ron, Cyril

    2015-08-01

    It is well known that geophysical fluids (atmosphere, oceans) excite Earth orientation. The influence is known to be dominant for polar motion, partly responsible for length-of-day changes, and very small effects are now observable also in nutation. Very recently several authors (Holme and de Viron 2005, Gibert and le Mouel 2008, Malkin 2013) noted that sudden changes of Earth's speed of rotation and phase/amplitude of the free motions of its spin axis (Chandler wobble, Free core nutation) occur near the epochs of geomagnetic jerks (GMJ - rapid changes of the secular variations of geomagnetic field). By using the numerical integration of broad-band Liouville equations (Brzezinski 1994) we demonstrate that if non-periodical bell-like excitations of limited length (app. 1 year) around the epochs of GMJ are added to atmospheric and oceanic excitations, the agreement between observed and calculated Earth orientation parameters is improved significantly.

  12. The evolution of the atmosphere of the earth

    NASA Technical Reports Server (NTRS)

    Hart, M. H.

    1978-01-01

    Computer simulations of the evolution of the earth's atmospheric composition and surface temperature have been carried out. The program took into account changes in the solar luminosity, variations in the earth's albedo, the greenhouse effect, variation in the biomass, and a variety of geochemical processes. Results indicate that prior to two billion years ago the earth had a partially reduced atmosphere, which included N2, CO2, reduced carbon compounds, some NH3, but no free H2. Surface temperatures were higher than now, due to a large greenhouse effect. When free O2 appeared the temperature fell sharply. Had earth been only slightly further from the sun, runaway glaciation would have occurred at that time. Simulations also indicate that a runaway greenhouse would have occurred early in earth's history had earth been only a few percent closer to the sun. It therefore appears that, taking into account the possibilities of either runaway glaciation or a runaway greenhouse effect, the continuously habitable zone about a solar-type star is rather narrow, extending only from roughly 0.95 to 1.01 AU.

  13. Earth's mysterious atmosphere. ATLAS 1: Teachers guide with activities

    NASA Technical Reports Server (NTRS)

    1991-01-01

    One of our mission's primary goals is to better understand the physics and chemistry of our atmosphere, the thin envelope of air that provides for human life and shields us from the harshness of space. The Space Shuttle Atlantis will carry the ATLAS 1 science instruments 296 km above Earth, so that they can look down into and through the various layers of the atmosphere. Five solar radiometers will precisely measure the amount of energy the Sun injects into Earth's environment. The chemistry at different altitudes will be measured very accurately by five other instruments called spectrometers. Much of our time in the cockpit of Atlantis will be devoted to two very exciting instruments that measure the auroras and the atmosphere's electrical characteristics. Finally, our ultraviolet telescope will probe the secrets of fascinating celestial objects. This Teacher's Guide is designed as a detective story to help you appreciate some of the many questions currently studied by scientists around the world. Many complex factors affect our atmosphere today, possibly even changing the course of global climate. All of us who live on Earth must recognize that we play an ever-growing role in causing some of these changes. We must solve this great atmospheric mystery if we are to understand all these changes and know what to do about them.

  14. Earth's mysterious atmosphere. ATLAS 1: Teachers guide with activities

    NASA Astrophysics Data System (ADS)

    1991-11-01

    One of our mission's primary goals is to better understand the physics and chemistry of our atmosphere, the thin envelope of air that provides for human life and shields us from the harshness of space. The Space Shuttle Atlantis will carry the ATLAS 1 science instruments 296 km above Earth, so that they can look down into and through the various layers of the atmosphere. Five solar radiometers will precisely measure the amount of energy the Sun injects into Earth's environment. The chemistry at different altitudes will be measured very accurately by five other instruments called spectrometers. Much of our time in the cockpit of Atlantis will be devoted to two very exciting instruments that measure the auroras and the atmosphere's electrical characteristics. Finally, our ultraviolet telescope will probe the secrets of fascinating celestial objects. This Teacher's Guide is designed as a detective story to help you appreciate some of the many questions currently studied by scientists around the world. Many complex factors affect our atmosphere today, possibly even changing the course of global climate. All of us who live on Earth must recognize that we play an ever-growing role in causing some of these changes. We must solve this great atmospheric mystery if we are to understand all these changes and know what to do about them.

  15. Earth's mysterious atmosphere. ATLAS 1: Teachers guide with activities

    SciTech Connect

    Not Available

    1991-11-01

    One of our mission's primary goals is to better understand the physics and chemistry of our atmosphere, the thin envelope of air that provides for human life and shields us from the harshness of space. The Space Shuttle Atlantis will carry the ATLAS 1 science instruments 296 km above Earth, so that they can look down into and through the various layers of the atmosphere. Five solar radiometers will precisely measure the amount of energy the Sun injects into Earth's environment. The chemistry at different altitudes will be measured very accurately by five other instruments called spectrometers. Much of our time in the cockpit of Atlantis will be devoted to two very exciting instruments that measure the auroras and the atmosphere's electrical characteristics. Finally, our ultraviolet telescope will probe the secrets of fascinating celestial objects. This Teacher's Guide is designed as a detective story to help you appreciate some of the many questions currently studied by scientists around the world. Many complex factors affect our atmosphere today, possibly even changing the course of global climate. All who live on Earth must recognize that they play an ever-growing role in causing some of these changes. People must solve this great atmospheric mystery if they are to understand all these changes and know what to do about them.

  16. Atmospheric CO2: principal control knob governing Earth's temperature.

    PubMed

    Lacis, Andrew A; Schmidt, Gavin A; Rind, David; Ruedy, Reto A

    2010-10-15

    Ample physical evidence shows that carbon dioxide (CO(2)) is the single most important climate-relevant greenhouse gas in Earth's atmosphere. This is because CO(2), like ozone, N(2)O, CH(4), and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapor can and does. Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect. Without the radiative forcing supplied by CO(2) and the other noncondensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state. PMID:20947761

  17. Atmospheric CO2: Principal Control Knob Governing Earth's Temperature

    NASA Technical Reports Server (NTRS)

    Lacis, Andrew A.; Schmidt, Gavin A.; Rind, David; Ruedy, Reto A.

    2010-01-01

    Ample physical evidence shows that carbon dioxide (CO2) is the single most important climate-relevant greenhouse gas in Earth s atmosphere. This is because CO2, like ozone, N2O, CH4, and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapor can and does. Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect. Without the radiative forcing supplied by CO2 and the other noncondensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state.

  18. Atmospheric circulation of hot Jupiters and super Earths

    NASA Astrophysics Data System (ADS)

    Kataria, Tiffany

    This dissertation explores the atmospheric circulation of extrasolar planets ranging from hot Jupiters to super Earths. For each of these studies, I utilize a three-dimensional circulation model coupled to a state-of-the-art, plane-parallel, two-stream, non-grey radiative transfer model dubbed the SPARC/MITgcm. First, I present models of the atmospheric circulation of eccentric hot Jupiters, a population which undergoes large variations in flux throughout their orbits. I demonstrate that the eccentric hot Jupiter regime is qualitatively similar to that of planets on circular orbits. For a select number of model integrations, I generate full-orbit lightcurves and find that the timing of transit and secondary eclipse viewed from Earth with respect to periapse and apoapse can greatly affect what is seen in infrared (IR) lightcurves. Next, I present circulation models of WASP-43b, a transiting hot Jupiter that is joining the ranks of HD 189733b and HD 209458b as a 'benchmark' hot Jupiter, with a wide array of observational constraints from the ground and space. Here I utilize the robust dataset of spectrophotometric observations taken with the Wide Field Camera 3 (WFC3) aboard the Hubble Space Telescope (HST) to interpret my model results. I find that an atmospheric composition of 5x solar provides the best match to the data, particularly in emission. Lastly, I present atmospheric simulations of the super Earth GJ 1214b, exploring the planet's circulation as a function of atmospheric metallicity and composition. I find that atmospheres with a low mean-molecular weight have strong day-night temperature variations at pressures above the infrared photosphere that lead to equatorial superrotation. For these atmospheres, the enhancement of atmospheric opacities with increasing metallicity leads to shallower atmospheric heating, larger day-night temperature variations and hence stronger superrotation. In comparison, atmospheres with a high mean-molecular weight have larger

  19. Earth-atmosphere evolution based on new determination of Devonian atmosphere Ar isotopic composition

    NASA Astrophysics Data System (ADS)

    Stuart, Finlay M.; Mark, Darren F.; Gandanger, Pierre; McConville, Paul

    2016-07-01

    The isotopic composition of the noble gases, in particular Ar, in samples of ancient atmosphere trapped in rocks and minerals provides the strongest constraints on the timing and rate of Earth atmosphere formation by degassing of the Earth's interior. We have re-measured the isotopic composition of argon in the Rhynie chert from northeast Scotland using a high precision mass spectrometer in an effort to provide constraints on the composition of Devonian atmosphere. Irradiated chert samples yield 40Ar/36Ar ratios that are often below the modern atmosphere value. The data define a 40Ar/36Ar value of 289.5 ± 0.4 at K/36Ar = 0. Similarly low 40Ar/36Ar are measured in un-irradiated chert samples. The simplest explanation for the low 40Ar/36Ar is the preservation of Devonian atmosphere-derived Ar in the chert, with the intercept value in 40Ar-39Ar-36Ar space representing an upper limit. In this case the Earth's atmosphere has accumulated only 3% (5.1 ± 0.4 ×1016 mol) of the total 40Ar inventory since the Devonian. The average accumulation rate of 1.27 ± 0.09 ×108 mol40Ar/yr overlaps the rate over the last 800 kyr. This implies that there has been no resolvable temporal change in the outgassing rate of the Earth since the mid-Palaeozoic despite the likely episodicity of Ar degassing from the continental crust. Incorporating the new Devonian atmosphere 40Ar/36Ar into the Earth degassing model of Pujol et al. (2013) provides the most precise constraints on atmosphere formation so far. The atmosphere formed in the first ∼100 Ma after initial accretion during a catastrophic degassing episode. A significant volume of 40Ar did not start to accumulate in the atmosphere until after 4 Ga which implies that stable K-rich continental crust did not develop until this time.

  20. Origin and evolution of the Earth's atmosphere and hydrosphere

    SciTech Connect

    Akbari, G.E.

    1984-01-01

    The composition of the outgassed fluid has been a point of serious debate. A model developed by Melton and Giardini has been used. In this model, the fluid inclusions in diamonds have been taken as original samples of the outgassed fluids. The model uses first order kinetics of the degassing processes of H2, CH4, N2, CO and Ar, and zero order kinetics for the degassing processes of H2O and CO2. Samples with compositions similar to the fluid included in diamonds were exposed to electric discharge, UV radiation and gamma radiation to formulate the equilibrium composition of the Earth's atmosphere. Small amounts of organic and inorganic compounds were formed in the samples by the radiation. The Melton/Giardini model was used to calculate the composition and pressure of primitive atmosphere of the Earth as a function of time, beginning 4.5 b.y. ago. Since light gases such as H2 and He escape from the Earth, and other degassed material undergoes numerous chemical and physical reactions, the Earth's atmosphere was quite different from the predicted composition using the uncorrected Melton/Giardini model.

  1. Surface and atmosphere parameter maps from earth-orbiting radiometers

    NASA Technical Reports Server (NTRS)

    Gloersen, P.

    1976-01-01

    Earlier studies have shown that an earth-orbiting electrically scanned microwave radiometer (ESMR) is capable of inferring the extent, concentration, and age of sea ice; the extent, concentration, and thickness of lake ice; rainfall rates over oceans; surface wind speeds over open water; particle size distribution in the deep snow cover of continental ice sheets; and soil moisture content in unvegetated fields. Most other features of the surface of the earth and its atmosphere require multispectral imaging techniques to unscramble the combined contributions of the atmosphere and the surface. Multispectral extraction of surface parameters is analyzed on the basis of a pertinent equation in terms of the observed brightness temperature, the emissivity of the surface which depends on wavelength and various parameters, the sensible temperature of the surface, and the total atmospheric opacity which is also wavelength dependent. Implementation of the multispectral technique is examined. Properties of the surface of the earth and its atmosphere to be determined from a scanning multichannel microwave radiometer are tabulated.

  2. 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.

  3. Biospheric-atmospheric coupling on the early Earth

    NASA Technical Reports Server (NTRS)

    Levine, J. S.

    1991-01-01

    Theoretical calculations performed with a one-dimensional photochemical model have been performed to assess the biospheric-atmospheric transfer of gases. Ozone reached levels to shield the Earth from biologically lethal solar ultraviolet radiation (220-300 nm) when atmospheric oxygen reached about 1/10 of its present atmospheric level. In the present atmosphere, about 90 percent of atmospheric nitrous oxide is destroyed via solar photolysis in the stratosphere with about 10 percent destroyed via reaction with excited oxygen atoms. The reaction between nitrous oxide and excited oxygen atoms leads to the production of nitric oxide in the stratosphere, which is responsible for about 70 percent of the global destruction of oxygen in the stratosphere. In the oxygen/ozone deficient atmosphere, solar photolysis destroyed about 100 percent of the atmospheric nitrous oxide, relegating the production of nitric oxide via reaction with excited oxygen to zero. Our laboratory and field measurements indicate that atmospheric oxygen promotes the biogenic production of N2O and NO via denitrification and the biogenic production of methane by methanogenesis.

  4. Constraining Archean Earth's Atmosphere with the Geological Record

    NASA Astrophysics Data System (ADS)

    Horan, A. M.; Domagal-Goldman, S. D.; Claire, M.

    2014-12-01

    A warm, water-bearing Archean Earth, when the Sun was young and faint, remains a paradox to the scientific world. Abundant geological data suggests that Archean Earth had standing water at the surface, despite the fainter Sun. An explanation of this paradox is vital to the understanding of Earth's history and coevolution with life. If the surface of the planet was not being kept warm by the Sun, which was 25% less luminous than now, it must have been kept warm a different way—by an atmospheric composition high in greenhouse gases. Constraints on these gases come from the geological record, which have provided proxies for the redox state of the atmosphere (limiting H2 and O2), the total atmospheric pressure, and the partial pressure of certain gases such as carbon dioxide (CO2) and methane (CH4). Previous attempts at solutions to the paradox are consistent with some, but not all, of the geological proxies. The constraints are used as inputs for a 1-D photochemical code, which calculates atmospheric composition and predicts the abundances of atmospheric gases that affect climate, particularly methane (CH4) and gaseous hydrogen (H2). A coupled 1-D radiative-convective climate code is then used to calculate the corresponding surface temperature. Critically, the improved photochemical code maintains strict redox boundary conditions, and is being further updated to ensure that the redox fluxes from volcanoes and mid-ocean ridge vents are consistent with both each other and the redox state of the mantle. These code improvements will lead to changes in both the inputs to the atmosphere from volcanoes and the sink for oxidants at mid-ocean ridges, in turn affecting the abundance of redox-sensitive greenhouse gases such as CH4 and H2. The main purpose of this project is to extend simulations of the Archean surface environment down into the mantle, and to search for a solution to the faint young sun paradox that is consistent with the geological proxies. Beyond having

  5. Structure and Abundance of Nitrous Oxide Complexes in Earth's Atmosphere.

    PubMed

    Salmon, Steven R; de Lange, Katrina M; Lane, Joseph R

    2016-04-01

    We have investigated the lowest energy structures and binding energies of a series of atmospherically relevant nitrous oxide (N2O) complexes using explicitly correlated coupled cluster theory. Specifically, we have considered complexes with nitrogen (N2-N2O), oxygen (O2-N2O), argon (Ar-N2O), and water (H2O-N2O). We have calculated rotational constants and harmonic vibrational frequencies for the complexes and the constituent monomers. Statistical mechanics was used to determine the thermodynamic parameters for complex formation as a function of temperature and pressure. These results, in combination with relevant atmospheric data, were used to estimate the abundance of N2O complexes in Earth's atmosphere as a function of altitude. We find that the abundance of N2O complexes in Earth's atmosphere is small but non-negligible, and we suggest that N2O complexes may contribute to absorption of terrestrial radiation and be relevant for understanding the atmospheric fate of N2O. PMID:26983553

  6. Quantitative infrared spectroscopy of minor constituents of the Earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Giver, L. P.; Goorvitch, D.; Spencer, M.; Valero, F. P. J.

    1990-01-01

    We obtain quantitative laboratory spectroscopic measurements of molecular constituents which are of importance in understanding the health of the Earth's atmosphere, and, in particular, emphasize those species which are important for understanding stratospheric kinetics or are used for long term monitoring of the stratosphere. Our measurements provide: (1) line and band intensity values which are needed to establish limits of detectability for as yet unobserved species and to quantify the abundance of those species which are observed; (2) line-positions, -half widths and pressure induced shifts are all needed for remote sensing techniques, and (3) data on the above basic molecular parameters at temperatures and pressures appropriate for the real atmosphere.

  7. Atmospheric Infrared Sounder on the Earth Observing System

    SciTech Connect

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

    1994-03-01

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

  8. Nonlinear dynamics of global atmospheric and earth system processes

    NASA Technical Reports Server (NTRS)

    Zhang, Taiping; Verbitsky, Mikhail; Saltzman, Barry; Mann, Michael E.; Park, Jeffrey; Lall, Upmanu

    1995-01-01

    During the grant period, the authors continued ongoing studies aimed at enhancing their understanding of the operation of the atmosphere as a complex nonlinear system interacting with the hydrosphere, biosphere, and cryosphere in response to external radiative forcing. Five papers were completed with support from the grant, representing contributions in three main areas of study: (1) theoretical studies of the interactive atmospheric response to changed biospheric boundary conditions measurable from satellites; (2) statistical-observational studies of global-scale temperature variability on interannual to century time scales; and (3) dynamics of long-term earth system changes associated with ice sheet surges.

  9. Interactions of CH4 and CO in the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Wofsy, S. C.

    1976-01-01

    Global distributions, sources, and sinks of methane and carbon monoxide in upper and lower levels of the earth's atmosphere, and the global budgets of methane and carbon monoxide, are studied, with emphasis on cumulative pollution. Stratospheric contents, vertical profiles of concentrations, simulation of vertical transport through the atmosphere, and latitudinal distributions are examined. Diffuse and localized (urban) concentrations of CO as pollutant are studied, and anthropogenic sources and sinks for CH4 and CO are considered. Perturbation of the CH4-CO-CO2 cycle, crucial to self-cleansing mechanisms of the troposphere, by anthropogenic CO emissions, and the effect of CO long life as global pollutant, are investigated.

  10. Photochemical production of formaldehyde in earth's primitive atmosphere

    NASA Technical Reports Server (NTRS)

    Pinto, J. P.; Gladstone, G. R.; Yung, Y. L.

    1980-01-01

    Formaldehyde could have been produced by photochemical reactions in the earth's primitive atmosphere, at a time when it consisted mainly of molecular nitrogen, water vapor, carbon dioxide, and trace amounts of molecular hydrogen and carbon monoxide. Removal of formaldehyde from the atmosphere by precipitation can provide a source of organic carbon to the oceans at the rate of 100 billion moles per year. Subsequent reactions of formaldehyde in primeval aquatic environments would have implications for the abiotic synthesis of complex organic molecules and the origin of life.

  11. Microwave emission and scattering from Earth surface and atmosphere

    NASA Technical Reports Server (NTRS)

    Kong, J. A.; Lee, M. C.

    1986-01-01

    Nonlinear Electromagnetic (EM) wave interactions with the upper atmosphere were investigated during the period 15 December 1985 to 15 June 1986. Topics discussed include: the simultaneous excitation of ionospheric density irregularities and Earth's magnetic field fluctuations; the electron acceleration by Langmuir wave turbulence; and the occurrence of artificial spread F. The role of thermal effects in generating ionospheric irregularities by Whistler waves, intense Quasi-DC electric fields, atmospheric gravity waves, and electrojets was investigated. A model was developed to explain the discrete spectrum of the resonant ultralow frequency (ULF) waves that are commonly observed in the magnetosphere.

  12. Photochemical production of formaldehyde in earth's primitive atmosphere

    NASA Astrophysics Data System (ADS)

    Pinto, J. P.; Gladstone, G. R.; Yung, Y. L.

    1980-10-01

    Formaldehyde could have been produced by photochemical reactions in the earth's primitive atmosphere, at a time when it consisted mainly of molecular nitrogen, water vapor, carbon dioxide, and trace amounts of molecular hydrogen and carbon monoxide. Removal of formaldehyde from the atmosphere by precipitation can provide a source of organic carbon to the oceans at the rate of 100 billion moles per year. Subsequent reactions of formaldehyde in primeval aquatic environments would have implications for the abiotic synthesis of complex organic molecules and the origin of life.

  13. Geospatial visualization of atmospheric chemistry satellite data using Google Earth

    NASA Astrophysics Data System (ADS)

    Burke, John

    2008-08-01

    Earth observation satellites employ various types of remote-sensing instruments to peer into the secrets of the atmosphere. Many of these instruments collect two-dimensional data stored as raster images which can be easily georeferenced and overlaid onto a virtual globe, with stunning results. However, certain instruments collect threedimensional science data which can pose a significant challenge for visualization efforts. The Tropospheric Emission Spectrometer (TES) is such an instrument which collects scientific data about atmospheric chemistry and stores the outputs in an Oracle database. With some imaginative programming, the data is transformed into interesting and information-packed visualizations using shell scripts, SQL scripts and Oracle stored procedures to yield Google Earthformatted files. This Google Earth content is hosted on the TES external web site for use by the public.

  14. Observing atmospheric tides in Earth rotation parameters with VLBI

    NASA Astrophysics Data System (ADS)

    Girdiuk, Anastasiia; Böhm, Johannes; Schindelegger, Michael

    2015-04-01

    In this study, we assess the contribution of diurnal (S1) and semi-diurnal (S2) atmospheric tides to variations in Earth rotation by analyzing Very Long Baseline Interferometry (VLBI) observations. Particular emphasis is placed on the dependency of S1 and S2 estimates on varying settings in the a priori delay model. We use hourly Earth rotation parameters (ERP) of polar motion and UT1 as determined with the Vienna VLBI Software (VieVS) from 25 years of VLBI observations and we adjust diurnal and semi-diurnal amplitudes to the hourly ERP estimates after disregarding the effect of high-frequency ocean tides. Prograde and retrograde polar motion coefficients are obtained for several solutions differing in processing strategies (with/without thermal deformation, time span of observations, choice of a priori ERP model and celestial pole offsets) and we compare the corresponding harmonics with those derived from atmospheric and non-tidal oceanic angular momentum estimates.

  15. Contributions of icy planetesimals to the Earth's early atmosphere.

    PubMed

    Owen, T C; Bar-Nun, A

    2001-01-01

    Laboratory experiments on the trapping of gases by ice forming at low temperatures implicate comets as major carriers of the heavy noble gases to the inner planets. These icy planetesimals may also have brought the nitrogen compounds that ultimately produced atmospheric N2. However, if the sample of three comets analyzed so far is typical, the Earth's oceans cannot have been produced by comets alone, they require an additional source of water with low D/H. The highly fractionated neon in the Earth's atmosphere may also indicate the importance of non-icy carriers of volatiles. The most important additional carrier is probably the rocky material comprising the bulk of the mass of these planets. Venus may require a contribution from icy planetesimals formed at the low temperatures characteristic of the Kuiper Belt. PMID:11599179

  16. Digital elevation model visibility including Earth's curvature and atmosphere refraction

    NASA Astrophysics Data System (ADS)

    Santossilva, Ewerton; Vieiradias, Luiz Alberto

    1990-03-01

    There are some instances in which the Earth's curvature and the atmospheric refraction, optical or electronic, are important factors when digital elevation models are used for visibility calculations. This work deals with this subject, suggesting a practical approach to solve this problem. Some examples, from real terrain data, are presented. The equipment used was an IBM-PC like computer with a SITIM graphic card.

  17. Nonlinear dynamics of global atmospheric and Earth system processes

    NASA Technical Reports Server (NTRS)

    Saltzman, Barry

    1993-01-01

    During the past eight years, we have been engaged in a NASA-supported program of research aimed at establishing the connection between satellite signatures of the earth's environmental state and the nonlinear dynamics of the global weather and climate system. Thirty-five publications and four theses have resulted from this work, which included contributions in five main areas of study: (1) cloud and latent heat processes in finite-amplitude baroclinic waves; (2) application of satellite radiation data in global weather analysis; (3) studies of planetary waves and low-frequency weather variability; (4) GCM studies of the atmospheric response to variable boundary conditions measurable from satellites; and (5) dynamics of long-term earth system changes. Significant accomplishments from the three main lines of investigation pursued during the past year are presented and include the following: (1) planetary atmospheric waves and low frequency variability; (2) GCM studies of the atmospheric response to changed boundary conditions; and (3) dynamics of long-term changes in the global earth system.

  18. A Comparative Study of Super-Earth Atmospheres

    NASA Astrophysics Data System (ADS)

    Dragomir, Diana; Benneke, Bjoern; Crossfield, Ian; Howard, Andrew; Knutson, Heather

    2014-12-01

    Ongoing transit surveys such as Kepler have resulted in the discovery of more than a dozen super?Earth planets with measured masses and radii. These planets are challenging targets for atmospheric characterization studies, and to date only one (GJ 1214b) has been studied in detail. In this proposal we focus on three additional super-Earths that are amenable to transmission spectroscopy studies due to their bright host stars (HD 97658b and 55 Cnc e) or their exceptionally low density (Kepler-138d). Our Spitzer measurements of these planets' transit depths will complement our already approved HST observations and contribute to distinguishing between clear hydrogen?dominated atmospheres and compact high-metallicity atmospheres, as well as constraining the composition of any high-altitude clouds. We will also search for evidence of carbon-bearing molecules, in particular for 55 Cnc e, a planet for which a carbon-rich composition has been suggested. Our observations will probe the poorly understood transition region between gas giant planets and terrestrial worlds, and provide constraints on the formation regions of these super-Earths. The results of this program will inform the direction to be taken by large-scale studies of these worlds with JWST.

  19. 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.

  20. Atmospheric Production of Perchlorate on Earth and Mars

    NASA Astrophysics Data System (ADS)

    Claire, M.; Catling, D. C.; Zahnle, K. J.

    2009-12-01

    Natural production and preservation of perchlorate on Earth occurs only in arid environments. Isotopic evidence suggests a strong role for atmospheric oxidation of chlorine species via pathways including ozone or its photochemical derivatives. As the Martian atmosphere is both oxidizing and drier than the driest places on Earth, we propose an atmospheric origin for the Martian perchlorates measured by NASA's Phoenix Lander. A variety of hypothetical formation pathways can be proposed including atmospheric photochemical reactions, electrostatic discharge, and gas-solid reactions. Here, we investigate gas phase formation pathways using a 1-D photochemical model (Catling et al. 2009, accepted by JGR). Because perchlorate-rich deposits in the Atacama desert are closest in abundance to perchlorate measured at NASA's Phoenix Lander site, we start with a study of the means to produce Atacama perchlorate. We found that perchlorate can be produced in sufficient quantities to explain the abundance of perchlorate in the Atacama from a proposed gas phase oxidation of chlorine volatiles to perchloric acid. These results are sensitive to estimated reaction rates for ClO3 species. The feasibility of gas phase production for the Atacama provides justification for further investigations of gas phase photochemistry as a possible source for Martian perchlorate. In addition to the Atacama results, we will present a preliminary study incorporating chlorine chemistry into an existing Martian photochemical model (Zahnle et al. JGR 2008).

  1. Chemical effects of large impacts on the earth's primitive atmosphere

    NASA Technical Reports Server (NTRS)

    Fegley, B., Jr.; Prinn, R. G.; Hartman, H.; Watkins, G. H.

    1986-01-01

    The production of HCN and H2CO by large impacts on the earth's primitive atmosphere is modelled using thermochemical equilibrium and chemical kinetic calculations of the composition of shocked air parcels for a wide range of temperatures, pressures, and initial compositions. For atmospheres with C/O of one or more, the results suggest that bolide impacts cause HCN volume mixing ratios of approximately 10 to the -3rd to -5th in the impact region and global average ratios of 10 to the -5th to the -12th. The corresponding H2CO mixing ratios in the impact region are 10 to the -7th to -9th; nonglobal mixing can occur, however, as H2CO is rapidly destroyed or rained out of the atmosphere within days to hours. Rainout to the oceans of 3-15 percent of the HCN produced can provide 3-14 x 10 to the 11th mol HCN per year.

  2. Global-scale teleconnections in the Earth's middle atmosphere

    NASA Astrophysics Data System (ADS)

    Shepherd, T. G.

    2009-05-01

    The global-scale circulation of the Earth's middle atmosphere is driven by angular momentum transfers effected by waves propagating up from the more turbulent, thermally-driven troposphere. The resulting effects on the middle atmosphere are largest in polar regions. This 'mechanical forcing' is an indirect response to the direct thermal forcing of the atmosphere by the Sun, and can act in a thermally-indirect manner, i.e. as a refrigerator. As it involves wave propagation, it can also act anti-diffusively, and non-locally. The basic physics of the process is described and examples given of how it can lead to global-scale teleconnections, both vertically and latitudinally. Parallels with the dynamics of the Sun will be mentioned.

  3. Evolution of a steam atmosphere during Earth's accretion.

    PubMed

    Zahnle, K J; Kasting, J F; Pollack, J B

    1988-01-01

    We have modeled the evolution of an impact-generated steam atmosphere surrounding an accreting Earth. The model assumes Safronov accretion; it includes degassing of planetesimals upon impact, thermal blanketing by a steam atmosphere, interchange of water between the surface and the interior, shock heating and convective cooling of Earth's interior, and hydrogen escape, both by a solar extreme ultraviolet (EUV) powered planetary wind and by impact erosion (atmospheric cratering). The model does not include atmophiles other than water, chemical reaction of water with metallic iron, core formation, compression, and spatial and temporal inhomogeneity of accretion. If the incoming planetesimals were too dry or the EUV flux too high, very little water would accumulate at the surface. Essentially all water retained by such a planet would be through rehydration of silicates. If rehydration were inefficient, very little water would be retained in any form. Degassing of wetter planetesimals produces a steam atmosphere over a magma ocean, the energy of accretion being sufficient to maintain a runaway greenhouse atmosphere. The mass of the atmosphere is limited by water's solubility in the (partial) melt. This type of solution is produced for a wide range of model parameters. During accretion, approximately 30 bars of water could have kept the surface at 1500 degrees K. As the accretional energy input declined below the runaway greenhouse threshold, the steam atmosphere rained out. Outgassing of dissolved water at the close of accretion is quantitatively important. These models can leave from approximately 100 to more than 300 bars of water at the surface at the close of accretion. In general, most of the water accreted remains dissolved in the mantle. H2 could have escaped as rapidly as it formed only if the planetesimals were relatively dry. Consequently H2 should have accumulated until it reached chemical equilibrium with water vapor. Impact erosion (escape caused by impact

  4. The role of impacting processes in the chemical evolution of the atmosphere of primordial Earth

    NASA Technical Reports Server (NTRS)

    Mukhin, Lev M.; Gerasimov, M. V.

    1991-01-01

    The role of impacting processes in the chemical evolution of the atmosphere of primordial Earth is discussed. The following subject areas are covered: (1) Earth's initial atmosphere; (2) continuous degassing; (3) impact processes and the Earth's protoatmosphere; and (4) the evolution of an impact-generated atmosphere.

  5. Quantifying Atmospheric Moist Processes from Earth Observations. Really?

    NASA Astrophysics Data System (ADS)

    Stephens, G. L.

    2015-12-01

    The amount of water in the Earth's atmosphere is tiny compared to all other sources of water on our planet, fresh or otherwise. However, this tiny amount of water is fundamental to most aspects of human life. The tiny amount of water that cycles from the Earth's surface, through condensation into clouds in the atmosphere returning as precipitation falling is not only natures way of delivering fresh water to land-locked human societies but it also exerts a fundamental control on our climate system producing the most important feedbacks in the system. The representation of these processes in Earth system models contain many errors that produce well now biases in the hydrological cycle. Surprisingly the parameterizations of these important processes are not well validated with observations. Part of the reason for this situation stems from the fact that process evaluation is difficult to achieve on the global scale since it has commonly been assumed that the static observations available from snap-shots of individual parameters contain little information on processes. One of the successes of the A-Train has been the development of multi-parameter analysis based on the multi-sensor data produced by the satellite constellation. This has led to new insights on how water cycles through the Earth's atmosphere. Examples of these insights will be highlighted. It will be described how the rain formation process has been observed and how this has been used to constrain this process in models, with a huge impact. How these observations are beginning to reveal insights on deep convection and examples of the use these observations applied to models will also be highlighted as will the effects of aerosol on clouds on radiation.

  6. Interferometric Characterization of the Earth's Atmosphere from Lagrange Point 2

    NASA Technical Reports Server (NTRS)

    Herman, Jay R.; Komar, George (Technical Monitor)

    2001-01-01

    Part of the NASA plans for future Earth Science missions calls for observations using novel vantage points that can produce science products otherwise unobtainable. Observations of the Earth from the Lagrange-2 point, L-2, (1.5 million km behind the Earth on the Earth-Sun line) affords a unique vantage point for atmospheric science. Spectral observation of the Earth's atmosphere using solar occultation techniques in the near infrared (1 to 4 microns) provides one of the most accurate methods of passively sensing attitude profiles of the major species (CO2, O3, O2, CH4, H2O N2O). While traditional polar orbiting occultation measurements can obtain about 14 measurements per day (2 per orbit), solar occultation observations from the Lagrange-2 point will yield hourly profile measurements at all latitudes. The expected spatial resolution is 2 km in altitude, 0.5 degrees in latitude, and 2 degrees in longitude. The result from 24 hours of observations will be a three-dimensional map of atmospheric composition. To accomplish this task from L-2 requires the development of a large moderate spectral resolution instrument whose entrance aperture is about 10 meters. Use of a standard telescope design with a 10-meter circular mirror or a 10-meter strip mirror would be prohibitively expensive and excessively massive. Instead, we are proposing the development of a 10-meter linear interferometer coupled to a Fourier transform imaging spectrometer. The result will be a highly efficient design with sufficient sensitivity, while having both spatial and spectral resolution to produce the desired results. Preliminary calculations show that seven species (CO2, O3, O2, CH4, H2O N2O) have clearly separated spectral features in the I to 4 microns range with sufficient absorption to produce profile information from near the Earth's surface to the middle stratosphere. For CO2 the estimated sensitivity to change is 0.33% or 1 part in 330. This should be sufficient to detect changes that are

  7. Atmospheric composition and climate on the early Earth

    PubMed Central

    Kasting, James F; Howard, M. Tazewell

    2006-01-01

    Oxygen isotope data from ancient sedimentary rocks appear to suggest that the early Earth was significantly warmer than today, with estimates of surface temperatures between 45 and 85°C. We argue, following others, that this interpretation is incorrect—the same data can be explained via a change in isotopic composition of seawater with time. These changes in the isotopic composition could result from an increase in mean depth of the mid-ocean ridges caused by a decrease in geothermal heat flow with time. All this implies that the early Earth was warm, not hot. A more temperate early Earth is also easier to reconcile with the long-term glacial record. However, what triggered these early glaciations is still under debate. The Paleoproterozoic glaciations at approximately 2.4 Ga were probably caused by the rise of atmospheric O2 and a concomitant decrease in greenhouse warming by CH4. Glaciation might have occurred in the Mid-Archaean as well, at approximately 2.9 Ga, perhaps as a consequence of anti-greenhouse cooling by hydrocarbon haze. Both glaciations are linked to decreases in the magnitude of mass-independent sulphur isotope fractionation in ancient rocks. Studying both the oxygen and sulphur isotopic records has thus proved useful in probing the composition of the early atmosphere. PMID:17008214

  8. Atmospheric composition and climate on the early Earth.

    PubMed

    Kasting, James F; Howard, M Tazewell

    2006-10-29

    Oxygen isotope data from ancient sedimentary rocks appear to suggest that the early Earth was significantly warmer than today, with estimates of surface temperatures between 45 and 85 degrees C. We argue, following others, that this interpretation is incorrect-the same data can be explained via a change in isotopic composition of seawater with time. These changes in the isotopic composition could result from an increase in mean depth of the mid-ocean ridges caused by a decrease in geothermal heat flow with time. All this implies that the early Earth was warm, not hot.A more temperate early Earth is also easier to reconcile with the long-term glacial record. However, what triggered these early glaciations is still under debate. The Paleoproterozoic glaciations at approximately 2.4Ga were probably caused by the rise of atmospheric O2 and a concomitant decrease in greenhouse warming by CH4. Glaciation might have occurred in the Mid-Archaean as well, at approximately 2.9Ga, perhaps as a consequence of anti-greenhouse cooling by hydrocarbon haze. Both glaciations are linked to decreases in the magnitude of mass-independent sulphur isotope fractionation in ancient rocks. Studying both the oxygen and sulphur isotopic records has thus proved useful in probing the composition of the early atmosphere. PMID:17008214

  9. Notes on Earth Atmospheric Entry for Mars Sample Return Missions

    NASA Technical Reports Server (NTRS)

    Rivell, Thomas

    2006-01-01

    The entry of sample return vehicles (SRVs) into the Earth's atmosphere is the subject of this document. The Earth entry environment for vehicles, or capsules, returning from the planet Mars is discussed along with the subjects of dynamics, aerodynamics, and heat transfer. The material presented is intended for engineers and scientists who do not have strong backgrounds in aerodynamics, aerothermodynamics and flight mechanics. The document is not intended to be comprehensive and some important topics are omitted. The topics considered in this document include basic principles of physics (fluid mechanics, dynamics and heat transfer), chemistry and engineering mechanics. These subjects include: a) fluid mechanics (aerodynamics, aerothermodynamics, compressible fluids, shock waves, boundary layers, and flow regimes from subsonic to hypervelocity; b) the Earth s atmosphere and gravity; c) thermal protection system design considerations; d) heat and mass transfer (convection, radiation, and ablation); e) flight mechanics (basic rigid body dynamics and stability); and f) flight- and ground-test requirements; and g) trajectory and flow simulation methods.

  10. Potential Biosignatures in Super-Earth Atmospheres II. Photochemical Responses

    PubMed Central

    Gebauer, S.; Godolt, M.; Palczynski, K.; Rauer, H.; Stock, J.; von Paris, P.; Lehmann, R.; Selsis, F.

    2013-01-01

    Abstract Spectral characterization of super-Earth atmospheres for planets orbiting in the habitable zone of M dwarf stars is a key focus in exoplanet science. A central challenge is to understand and predict the expected spectral signals of atmospheric biosignatures (species associated with life). Our work applies a global-mean radiative-convective-photochemical column model assuming a planet with an Earth-like biomass and planetary development. We investigated planets with gravities of 1g and 3g and a surface pressure of 1 bar around central stars with spectral classes from M0 to M7. The spectral signals of the calculated planetary scenarios have been presented by in an earlier work by Rauer and colleagues. The main motivation of the present work is to perform a deeper analysis of the chemical processes in the planetary atmospheres. We apply a diagnostic tool, the Pathway Analysis Program, to shed light on the photochemical pathways that form and destroy biosignature species. Ozone is a potential biosignature for complex life. An important result of our analysis is a shift in the ozone photochemistry from mainly Chapman production (which dominates in Earth's stratosphere) to smog-dominated ozone production for planets in the habitable zone of cooler (M5–M7)-class dwarf stars. This result is associated with a lower energy flux in the UVB wavelength range from the central star, hence slower planetary atmospheric photolysis of molecular oxygen, which slows the Chapman ozone production. This is important for future atmospheric characterization missions because it provides an indication of different chemical environments that can lead to very different responses of ozone, for example, cosmic rays. Nitrous oxide, a biosignature for simple bacterial life, is favored for low stratospheric UV conditions, that is, on planets orbiting cooler stars. Transport of this species from its surface source to the stratosphere where it is destroyed can also be a key process

  11. Earth Rotation and Coupling to Changes in Atmospheric Angular Momentum

    NASA Technical Reports Server (NTRS)

    Rosen, Richard D.; Frey, H. (Technical Monitor)

    2000-01-01

    The research supported under the contract dealt primarily with: (a) the mechanisms responsible for the exchange of angular momentum between the solid Earth and atmosphere; (b) the quality of the data sets used to estimate atmospheric angular momentum; and (c) the ability of these data and of global climate models to detect low-frequency signals in the momentum and, hence, circulation of the atmosphere. Three scientific papers reporting on the results of this research were produced during the course of the contract. These papers identified the particular torques responsible for the peak in atmospheric angular momentum and length-of-day during the 1982-93 El Nino event, and, more generally, the relative roles of torques over land and ocean in explaining the broad spectrum of variability in the length-of-day. In addition, a tendency for interannual variability in atmospheric angular momentum to increase during the last several decades of the 20th century was found in both observations and a global climate model experiment.

  12. 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.

  13. Integrating the Earth, Atmospheric, and Ocean Sciences at Millersville University

    NASA Astrophysics Data System (ADS)

    Clark, R. D.

    2005-12-01

    For nearly 40 years, the Department of Earth Sciences at Millersville University (MU-DES) of Pennsylvania has been preparing students for careers in the earth, atmospheric, and ocean sciences by providing a rigorous and comprehensive curricula leading to B.S. degrees in geology, meteorology, and oceanography. Undergraduate research is a hallmark of these earth sciences programs with over 30 students participating in some form of meritorious research each year. These programs are rich in applied physics, couched in mathematics, and steeped in technical computing and computer languages. Our success is measured by the number of students that find meaningful careers or go on to earn graduate degrees in their respective fields, as well as the high quality of faculty that the department has retained over the years. Student retention rates in the major have steadily increased with the introduction of a formal learning community and peer mentoring initiatives, and the number of new incoming freshmen and transfer students stands at an all-time high. Yet until recently, the disciplines have remained largely disparate with only minor inroads made into integrating courses that seek to address the Earth as a system. This is soon to change as the MU-DES unveils a new program leading to a B.S. in Integrated Earth Systems. The B.S. in Integrated Earth Systems (ISS) is not a reorganization of existing courses to form a marketable program. Instead, it is a fully integrated program two years in development that borrows from the multi-disciplinary backgrounds and experiences of faculty, while bringing in resources that are tailored to visualizing and modeling the Earth system. The result is the creation of a cross-cutting curriculum designed to prepare the 21st century student for the challenges and opportunities attending the holistic study of the Earth as a system. MU-DES will continue to offer programs leading to degrees in geology, meteorology, and ocean science, but in addition

  14. Aerosol in the upper layer of earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Morozhenko, A. V.; Vidmachenko, A. P.; Nevodovskii, P. V.

    2013-09-01

    Aerosol layers exist in the upper atmospheres of Venus, Mars, Jupiter, Saturn and the Earth. The reason for their existence may be meteorites, rings, and removal of particles of planetary origin. Observations from 1979 to 1992 showed that the optical thickness of aerosol over the Earth's polar regions changed from tau =0.0002 up to tau =.1 for lambda = 1000 nm. The greatest values of tau were in 1984 and 1992 and they were preceded by a strong volcanic activity of El Chichon (1982) and Pinatubo (1991). We show that the above-mentioned increase in the optical thickness of the stratosphere aerosol can lead to the ozone layer decrease detected in 1970. The stratospheric aerosol nature (real part of refractive index), effective particle size r and changing tau with latitude remain un solved. Among distance methods for the determination of nr and r efficient is the analysis of the phase dependence of the polarization degree. The observational values of the intensity and pol arization degree invisible light are due to optical properties of the surface and optical thickness of the atmosphere, the values of which vary with latitude, longitude and time. Therefore, it is impossible to identify accurately the stratospheric aerosol contribution. When observing in UV at lambda < 300 nm, the ozone layer cuts off the influence of the surface and the Earth's atmosphere to an altitude from 20 to 25 km. In this spectral region some negative factors can take place, namely, the emission of various gases playing depolarizing role, horizontal inhomogeneity of the effective optical thickness of ozone layer, and oriented particles (the polarization plane variation points to their presence).

  15. ACE infrared spectral atlases of the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Hughes, Ryan; Bernath, Peter; Boone, Chris

    2014-11-01

    Five infrared atmospheric atlases are presented using solar occultation spectra from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) in low earth orbit. The spectral atlases were created for Arctic summer, Arctic winter, mid-latitude summer, mid-latitude winter and the tropics. Each covers the spectral range from 700 to 4400 cm-1 and consists of 31 spectra that span an altitude range of 6-126 km in 4-km altitude intervals. To improve the signal-to-noise ratio, each spectrum in the atlas is an average of at least several hundred individual ACE-FTS limb transmission spectra. Representative plots in pdf format at 10 km (troposphere), 30 km (stratosphere), 70 km (mesosphere), and 110 km (lower thermosphere) are also available.

  16. Carbon monoxide in the earth's atmosphere - Increasing trend

    NASA Technical Reports Server (NTRS)

    Khalil, M. A. K.; Rasmussen, R. A.

    1984-01-01

    The results of an analysis of more than 60,000 atmospheric measurements of carbon monoxide taken over 3-1/2 years at Cape Meares, Oregon (45 deg N, 125 deg W), indicate that the background concentration of this gas is increasing. The rate of increase, although uncertain, is about 6 percent per year on average. Human activities are the likely cause of a substantial portion of this observed increase; however, because of the short atmospheric lifetime of carbon monoxide and the relatively few years of observations, fluctuations of sources and sinks related to the natural variability of climate may have affected the observed trend. Increased carbon monoxide may deplete tropospheric hydroxyl radicals, slowing down the removal of dozens of man-made and anthropogenic trace gases and thus indirectly affecting the earth's climate and possibly the stratospheric ozone layer.

  17. Potential biosignatures in super-Earth atmospheres II. Photochemical responses.

    PubMed

    Grenfell, J L; Gebauer, S; Godolt, M; Palczynski, K; Rauer, H; Stock, J; von Paris, P; Lehmann, R; Selsis, F

    2013-05-01

    Spectral characterization of super-Earth atmospheres for planets orbiting in the habitable zone of M dwarf stars is a key focus in exoplanet science. A central challenge is to understand and predict the expected spectral signals of atmospheric biosignatures (species associated with life). Our work applies a global-mean radiative-convective-photochemical column model assuming a planet with an Earth-like biomass and planetary development. We investigated planets with gravities of 1g and 3g and a surface pressure of 1 bar around central stars with spectral classes from M0 to M7. The spectral signals of the calculated planetary scenarios have been presented by in an earlier work by Rauer and colleagues. The main motivation of the present work is to perform a deeper analysis of the chemical processes in the planetary atmospheres. We apply a diagnostic tool, the Pathway Analysis Program, to shed light on the photochemical pathways that form and destroy biosignature species. Ozone is a potential biosignature for complex life. An important result of our analysis is a shift in the ozone photochemistry from mainly Chapman production (which dominates in Earth's stratosphere) to smog-dominated ozone production for planets in the habitable zone of cooler (M5-M7)-class dwarf stars. This result is associated with a lower energy flux in the UVB wavelength range from the central star, hence slower planetary atmospheric photolysis of molecular oxygen, which slows the Chapman ozone production. This is important for future atmospheric characterization missions because it provides an indication of different chemical environments that can lead to very different responses of ozone, for example, cosmic rays. Nitrous oxide, a biosignature for simple bacterial life, is favored for low stratospheric UV conditions, that is, on planets orbiting cooler stars. Transport of this species from its surface source to the stratosphere where it is destroyed can also be a key process. Comparing 1g with

  18. Photochemistry of methane in the earth's early atmosphere

    NASA Astrophysics Data System (ADS)

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

    The photochemical behavior of methane in the early terrestrial atmosphere is investigated with a detailed model in order to determine how much CH4 might have been present and what types of higher hydroocarbons could have been formed. It is found that any primordial methane accumulated during the course of earth accretion would have been dissipated by photochemical reactions in the atmosphere in a geologically short period of time after the segregation of the core. Abiotic sources of methane are not likely to have been large enough to sustain CH4 mixing ratios as high as 10 to the -6th, the threshold for a possible methane greenhouse, with a CO-rich atmosphere being a possible exception. After the origin of life an increasing biogenic source of methane may have driven CH4 mixing ratios well above 10 to the 6th. The rise of atmospheric oxygen in the early Proterozoic may have led to a more rapid photochemical destruction of methane, lowering the mixing ratio to its present value.

  19. Particle motion in atmospheric boundary layers of Mars and Earth

    NASA Technical Reports Server (NTRS)

    White, B. R.; Iversen, J. D.; Greeley, R.; Pollack, J. B.

    1975-01-01

    To study the eolian mechanics of saltating particles, both an experimental investigation of the flow field around a model crater in an atmospheric boundary layer wind tunnel and numerical solutions of the two- and three-dimensional equations of motion of a single particle under the influence of a turbulent boundary layer were conducted. Two-dimensional particle motion was calculated for flow near the surfaces of both Earth and Mars. For the case of Earth both a turbulent boundary layer with a viscous sublayer and one without were calculated. For the case of Mars it was only necessary to calculate turbulent boundary layer flow with a laminar sublayer because of the low values of friction Reynolds number; however, it was necessary to include the effects of slip flow on a particle caused by the rarefied Martian atmosphere. In the equations of motion the lift force functions were developed to act on a single particle only in the laminar sublayer or a corresponding small region of high shear near the surface for a fully turbulent boundary layer. The lift force functions were developed from the analytical work by Saffman concerning the lift force acting on a particle in simple shear flow.

  20. Formation of the Aerosol of Space Origin in Earth's Atmosphere

    NASA Technical Reports Server (NTRS)

    Kozak, P. M.; Kruchynenko, V. G.

    2011-01-01

    The problem of formation of the aerosol of space origin in Earth s atmosphere is examined. Meteoroids of the mass range of 10-18-10-8 g are considered as a source of its origin. The lower bound of the mass range is chosen according to the data presented in literature, the upper bound is determined in accordance with the theory of Whipple s micrometeorites. Basing on the classical equations of deceleration and heating for small meteor bodies we have determined the maximal temperatures of the particles, and altitudes at which they reach critically low velocities, which can be called as velocities of stopping . As a condition for the transformation of a space particle into an aerosol one we have used the condition of non-reaching melting temperature of the meteoroid. The simplified equation of deceleration without earth gravity and barometric formula for the atmosphere density are used. In the equation of heat balance the energy loss for heating is neglected. The analytical solution of the simplified equations is used for the analysis.

  1. The NASA MSFC Earth Global Reference Atmospheric Model-2007 Version

    NASA Technical Reports Server (NTRS)

    Leslie, F.W.; Justus, C.G.

    2008-01-01

    Reference or standard atmospheric models have long been used for design and mission planning of various aerospace systems. The NASA/Marshall Space Flight Center (MSFC) Global Reference Atmospheric Model (GRAM) was developed in response to the need for a design reference atmosphere that provides complete global geographical variability, and complete altitude coverage (surface to orbital altitudes) as well as complete seasonal and monthly variability of the thermodynamic variables and wind components. A unique feature of GRAM is that, addition to providing the geographical, height, and monthly variation of the mean atmospheric state, it includes the ability to simulate spatial and temporal perturbations in these atmospheric parameters (e.g. fluctuations due to turbulence and other atmospheric perturbation phenomena). A summary comparing GRAM features to characteristics and features of other reference or standard atmospheric models, can be found Guide to Reference and Standard Atmosphere Models. The original GRAM has undergone a series of improvements over the years with recent additions and changes. The software program is called Earth-GRAM2007 to distinguish it from similar programs for other bodies (e.g. Mars, Venus, Neptune, and Titan). However, in order to make this Technical Memorandum (TM) more readable, the software will be referred to simply as GRAM07 or GRAM unless additional clarity is needed. Section 1 provides an overview of the basic features of GRAM07 including the newly added features. Section 2 provides a more detailed description of GRAM07 and how the model output generated. Section 3 presents sample results. Appendices A and B describe the Global Upper Air Climatic Atlas (GUACA) data and the Global Gridded Air Statistics (GGUAS) database. Appendix C provides instructions for compiling and running GRAM07. Appendix D gives a description of the required NAMELIST format input. Appendix E gives sample output. Appendix F provides a list of available

  2. Earth

    NASA Technical Reports Server (NTRS)

    Carr, M. H.

    1984-01-01

    The following aspects of the planet Earth are discussed: plate tectonics, the interior of the planet, the formation of the Earth, and the evolution of the atmosphere and hydrosphere. The Earth's crust, mantle, and core are examined along with the bulk composition of the planet.

  3. Nonlinear dynamics of global atmospheric and Earth-system processes

    NASA Technical Reports Server (NTRS)

    Saltzman, Barry; Ebisuzaki, Wesley; Maasch, Kirk A.; Oglesby, Robert; Pandolfo, Lionel

    1990-01-01

    Researchers are continuing their studies of the nonlinear dynamics of global weather systems. Sensitivity analyses of large-scale dynamical models of the atmosphere (i.e., general circulation models i.e., GCM's) were performed to establish the role of satellite-signatures of soil moisture, sea surface temperature, snow cover, and sea ice as crucial boundary conditions determining global weather variability. To complete their study of the bimodality of the planetary wave states, they are using the dynamical systems approach to construct a low-order theoretical explanation of this phenomenon. This work should have important implications for extended range forecasting of low-frequency oscillations, elucidating the mechanisms for the transitions between the two wave modes. Researchers are using the methods of jump analysis and attractor dimension analysis to examine the long-term satellite records of significant variables (e.g., long wave radiation, and cloud amount), to explore the nature of mode transitions in the atmosphere, and to determine the minimum number of equations needed to describe the main weather variations with a low-order dynamical system. Where feasible they will continue to explore the applicability of the methods of complex dynamical systems analysis to the study of the global earth-system from an integrative viewpoint involving the roles of geochemical cycling and the interactive behavior of the atmosphere, hydrosphere, and biosphere.

  4. Sensitivity on earth core and mantle densities using atmospheric neutrinos

    SciTech Connect

    Borriello, E.; Marotta, A.; Miele, G.; Pisanti, O.; Strolin, P.; Mangano, G.; Migliozzi, P.; Moura, C.A.; Pastor, S. E-mail: mangano@na.infn.it E-mail: miele@na.infn.it E-mail: moura@na.infn.it E-mail: pisanti@na.infn.it

    2009-06-01

    Neutrino radiography may provide an alternative tool to study the very deep structures of the Earth. Though these measurements are unable to resolve the fine density layer features, nevertheless the information which can be obtained are independent and complementary to the more conventional seismic studies. The aim of this paper is to assess how well the core and mantle averaged densities can be reconstructed through atmospheric neutrino radiography. We find that about a 2% sensitivity for the mantle and 5% for the core could be achieved for a ten year data taking at an underwater km{sup 3} Neutrino Telescope. This result does not take into account systematics related to the details of the experimental apparatus.

  5. Day time flight of micrometeoroid in upper earth atmosphere

    NASA Astrophysics Data System (ADS)

    Misra, Shikha; Mishra, S. K.

    2016-07-01

    In this paper, the flight of micro (μ)-meteoroid in the day time earth environment has been discussed and the role of photoemission due to solar radiation, in addition to other relevant emission processes, viz. thermionic/charge desorption has been explored. Following Mendis et al., the meteoroid flight has been described by a consistent analytical model which manifests the continuity equations for the momentum, energy, charge and mass of micrometeoroids entering in the earth environment with a finite speed and at a finite angle. The altitude profiles of the characteristic features during flight, viz. surface heating, particle size, mass-loss, charging and its consequence on local atmospheric plasma has been examined in terms of the angle of entrance, entry speed, size, material work function/photoefficiency and incident solar flux. The numerical results show that the photoemission from micrometeoroid significantly contributes in meteoric electrons generation in its path in beginning and end phase of the flight; of course the energetics over the meteoroid in its travel is dominated by mass ablation process.

  6. Day time flight of micrometeoroid in upper earth atmosphere

    NASA Astrophysics Data System (ADS)

    Misra, Shikha; Mishra, S. K.

    2016-04-01

    In this paper the flight of micro (μ)-meteoroid in the day time earth environment has been discussed and the role of photoemission due to solar radiation, in addition to other relevant emission processes viz. thermionic/ charge desorption has been explored. Following Mendis et al. (JASTP 67, 1178, 2005), the meteoroid flight has been described by a consistent analytical model which manifest the continuity equations for the momentum, energy, charge and mass of μ-meteoroids entering in the earth environment with a finite speed and at a finite angle. The altitude profiles of the characteristic features during flight viz. surface heating, particle size, mass loss, charging and its consequence on local atmospheric plasma has been examined in terms of the angle of entrance, entry speed, size, material work function/ photo-efficiency and incident solar flux. The numerical results show that the photoemission from μ-meteoroid significantly contributes in meteoric electrons generation in its path in beginning and end phase of the flight; of course the energetics over the meteoroid in its travel is dominated by mass ablation process.

  7. Radiation Transfer Model for Aerosol Events in the Earth Atmosphere

    NASA Astrophysics Data System (ADS)

    Mukai, Sonoyo; Yokomae, Takuma; Nakata, Makiko; Sano, Itaru

    Recently large scale-forest fire, which damages the Earth environment as biomass burning and emission of carbonaceous particles, frequently occurs due to the unstable climate and/or global warming tendency. It is also known that the heavy soil dust is transported from the China continent to Japan on westerly winds, especially in spring. Furthermore the increasing emis-sions of anthropogenic particles associated with continuing economic growth scatter serious air pollutants. Thus atmospheric aerosols, especially in Asia, are very complex and heavy loading, which is called aerosol event. In the case of aerosol events, it is rather difficult to do the sun/sky photometry from the ground, however satellite observation is an effective for aerosol monitoring. Here the detection algorithms from space for such aerosol events as dust storm or biomass burn-ing are dealt with multispectral satellite data as ADEOS-2/GLI, Terra/Aqua/MODIS and/or GOSAT/CAI first. And then aerosol retrieval algorithms are examined based on new radiation transfer code for semi-infinite atmosphere model. The derived space-based results are validated with ground-based measurements and/or model simulations. Namely the space-or surface-based measurements, multiple scattering calculations and model simulations are synthesized together for aerosol retrieval in this work.

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

    NASA Technical Reports Server (NTRS)

    1988-01-01

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

  9. Photoevaporation of Earth and Super-Earth Atmospheres in the Habitable Zones of M Dwarfs

    NASA Astrophysics Data System (ADS)

    Mohanty, Subhanjoy

    2015-08-01

    Kepler data show that multiple terrestrial-sized planets (i.e., Earths / super-Earths), packed in very close to the central star, are the norm in exoplanetary systems around low-mass stars. Around M dwarfs, a significant fraction of these planets reside within the Habitable Zone (HZ). This has kindled intense excitement about the possibility of finding habitable planets around these cool red stars. However, M dwarfs also remain extremely magnetically active for much longer than solar-type stars: e.g., an M3 dwarf evinces saturated levels of coronal and chromospheric activity over Gyr timescales, compared to ~100 Myr for solar-mass stars. Thus, basal levels of coronal/chromospheric X-ray/EUV emission from M dwarfs, integrated over their saturated activity lifetimes, may severely photoevaporate the atmospheres of terrestrial planets in M dwarf HZs; this would only be exacerbated by flares (which are correspondingly more intense in active M dwarfs). Here we present detailed hydrodynamic calculations of such photoevaporation for planets spanning a range of Earth/super-Earth sizes, residing in the HZ of M dwarfs of various spectral sub-types, over Gyr evolutionary timescales. Our calculations include the effects of: (1) simultaneous X-ray and EUV heating, using state-of-the-art stellar XUV SED models; (2) the change in the stellar XUV SED over evolutionary timescales; (3) realistic radiative losses (which can both dominate and vary in time); (4) thermal evolution of the planetary core; and (5) a range of initial planetary entropies (i.e.,`hot' or `cold' start) and core compositions. The analysis yields the location and extent of the HZ as a function of planetary mass, core composition, initial conditions and M sub-type. We will focus on H/He dominated (i.e., solar abundance) atmospheres; however, we will also discuss qualtitative trends for CO2 / H2O dominated atmospheres, which we are beginning to explore by coupling a detailed photochemical code with our hydrodynamic

  10. Catching Comet's Particles in the Earth's Atmosphere by Using Balloons

    NASA Astrophysics Data System (ADS)

    Potashko, Oleksandr; Viso, Michel

    The project is intended to catch cometary particles in the atmosphere by using balloons. The investigation is based upon knowledge that the Earth crosses the comet’s tails during the year. One can catch these particles at different altitudes in the atmosphere. So, we will be able to gradually advance in the ability to launch balloons from low to high altitudes and try to catch particles from different comet tails. The maximum altitude that we have to reach is 40 km. Both methods - distance observation and cometary samples from mission Stardust testify to the presence of organic components in comet’s particles. It would be useful to know more details about this organic matter for astrobiology; besides, the factor poses danger to the Earth. Moreover, it is important to prove that it is possible to get fundamental scientific results at low cost. In the last 5 years launching balloons has become popular and this movement looks like hackers’ one - as most of them occur without launch permission to airspace. The popularity of ballooning is connected with low cost of balloon, GPS unit, video recording unit. If you use iPhone, you have a light solution with GPS, video, picture and control function in one unit. The price of balloon itself begins from $50; it depends on maximum altitude, payload weight and material. Many university teams realized balloon launching and reached even stratosphere at an altitude of 33 km. But most of them take only video and picture. Meanwhile, it is possible to carry out scientific experiments by ballooning, for example to collect comet particles. There is rich experience at the moment of the use of mineral, chemical and isotopic analysis techniques and data of the comet’s dust after successful landing of StarDust capsule with samples in 2006. Besides, we may use absolutely perfect material to catch particles in the atmosphere, which was used by cosmic missions such as Stardust and Japanese Hayabusa. As to balloon launches, we could use

  11. Three-Dimensional Orbits of Earth Satellites, Including Effects of Earth Oblateness and Atmospheric Rotation

    NASA Technical Reports Server (NTRS)

    Nielsen, Jack N.; Goodwin, Frederick K.; Mersman, William A.

    1958-01-01

    The principal purpose of the present paper is to present sets of equations which may be used for calculating complete trajectories of earth satellites from outer space to the ground under the influence of air drag and gravity, including oblateness effects, and to apply these to several examples of entry trajectories starting from a circular orbit. Equations of motion, based on an "instantaneous ellipse" technique, with polar angle as independent variable, were found suitable for automatic computation of orbits in which the trajectory consists of a number of revolutions. This method is suitable as long as the trajectory does not become nearly vertical. In the terminal phase of the trajectories, which are nearly vertical, equations of motion in spherical polar coordinates with time as the independent variable were found to be more suitable. In the first illustrative example the effects of the oblateness component of the earth's gravitational field and of atmospheric rotation were studied for equatorial orbits. The satellites were launched into circular orbits at a height of 120 miles, an altitude sufficiently high that a number of revolutions could be studied. The importance of the oblateness component of the earth's gravitational field is shown by the fact that a satellite launched at circular orbital speed, neglecting oblateness, has a perigee some 67,000 feet lower when oblateness forces are included in the equations of motion than when they are not included. Also, the loss in altitude per revolution is double that of a satellite following an orbit not subject to oblateness. The effect of atmospheric rotation on the loss of altitude per revolution was small. As might be surmised, the regression of the line of nodes as predicted by celestial mechanics is unchanged when drag is included. It is clear that the inclination of the orbital plane to the equator will be relatively unaffected by drag for no atmospheric rotation since the drag lies in the orbital plane in

  12. The equilibrium of atmospheric sodium. [in atmospheres of Earth, Io, Mercury and Moon

    NASA Technical Reports Server (NTRS)

    Hunten, Donald M.

    1992-01-01

    We now have four examples of planetary objects with detectable sodium (and potassium) in their atmospheres: Earth, Io, Mercury and the moon. After a summary of the observational data, this survey discusses proposed sources and sinks. It appears that Io's surface material is rich in frozen SO2, but with around 1 percent of some sodium compound. The Io plasma torus contains ions of S, O and Na, also with at least one molecular ion containing Na. In turn, impact by these ions probably sustains the torus, as well as an extended neutral corona. A primary source for the Earth, Mercury and the moon is meteoroidal bombardment; at Mercury and perhaps the moon it may be supplemented by degassing of atoms from the regolith. Photoionization is important everywhere, although hot electrons are dominant at Io.

  13. National Chemistry Week 2003: Earth's Atmosphere and Beyond. JCE Resources for Chemistry and the Atmosphere

    NASA Astrophysics Data System (ADS)

    Jacobsen, Erica K.

    2003-10-01

    This annotated bibliography collects the best that past issues of the Journal of Chemical Education have to offer for use with this year's National Chemistry Week theme: Earth's Atmosphere and Beyond. Each article has been characterized as a demonstration, experiment, activity, informational, or software/video item; several fit in more than one classification. The most recent articles are listed first. Also included is an evaluation as to which levels the article may serve. Articles that appeared adaptable to other levels, but are not designed explicitly for those levels, are labeled "poss. h.s." "poss. elem.", and so forth.

  14. High-resolution transmission spectrum of the Earth's atmosphere-seeing Earth as an exoplanet using a lunar eclipse

    NASA Astrophysics Data System (ADS)

    Yan, F.; Fosbury, R. A. E.; Petr-Gotzens, M. G.; Zhao, G.; Wang, W.; Wang, L.; Liu, Y.; Pallé, E.

    2015-04-01

    With the rapid developments in the exoplanet field, more and more terrestrial exoplanets are being detected. Characterizing their atmospheres using transit observations will become a key datum in the quest for detecting an Earth-like exoplanet. The atmospheric transmission spectrum of our Earth will be an ideal template for comparison with future exo-Earth candidates. By observing a lunar eclipse, which offers a similar configuration to that of an exoplanet transit, we have obtained a high-resolution and high signal-to-noise ratio (SNR) transmission spectrum of the Earth's atmosphere. This observation was performed with the High Resolution Spectrograph at Xinglong Station, China during the total lunar eclipse in December 2011. We compare the observed transmission spectrum with our atmospheric model, and determine the characteristics of the various atmospheric species in detail. In the transmission spectrum, O2, O3, O2 . O2, NO2 and H2O are detected, and their column densities are measured and compared with the satellites data. The visible Chappuis band of ozone produces the most prominent absorption feature, which suggests that ozone is a promising molecule for the future exo-Earth characterization. Due to the high resolution and high SNR of our spectrum, several novel details of the Earth atmosphere's transmission spectrum are presented. The individual O2 lines are resolved and O2 isotopes are clearly detected. Our new observations do not confirm the absorption features of Ca II or Na I which have been reported in previous lunar eclipse observations. However, features in these and some other strong Fraunhofer line positions do occur in the observed spectrum. We propose that these are due to a Raman-scattered component in the forward-scattered sunlight appearing in the lunar umbral spectrum. Water vapour absorption is found to be rather weak in our spectrum because the atmosphere we probed is relatively dry, which prompts us to discuss the detectability of water

  15. ATMOSPHERIC RETRIEVAL FOR SUPER-EARTHS: UNIQUELY CONSTRAINING THE ATMOSPHERIC COMPOSITION WITH TRANSMISSION SPECTROSCOPY

    SciTech Connect

    Benneke, Bjoern; Seager, Sara

    2012-07-10

    We present a retrieval method based on Bayesian analysis to infer the atmospheric compositions and surface or cloud-top pressures from transmission spectra of exoplanets with general compositions. In this study, we identify what can unambiguously be determined about the atmospheres of exoplanets from their transmission spectra by applying the retrieval method to synthetic observations of the super-Earth GJ 1214b. Our approach to inferring constraints on atmospheric parameters is to compute their joint and marginal posterior probability distributions using the Markov Chain Monte Carlo technique in a parallel tempering scheme. A new atmospheric parameterization is introduced that is applicable to general atmospheres in which the main constituent is not known a priori and clouds may be present. Our main finding is that a unique constraint of the mixing ratios of the absorbers and two spectrally inactive gases (such as N{sub 2} and primordial H{sub 2}+ He) is possible if the observations are sufficient to quantify both (1) the broadband transit depths in at least one absorption feature for each absorber and (2) the slope and strength of the molecular Rayleigh scattering signature. A second finding is that the surface pressure or cloud-top pressure can be quantified if a surface or cloud deck is present at low optical depth. A third finding is that the mean molecular mass can be constrained by measuring either the Rayleigh scattering slope or the shapes of the absorption features, thus enabling one to distinguish between cloudy hydrogen-rich atmospheres and high mean molecular mass atmospheres. We conclude, however, that without the signature of molecular Rayleigh scattering-even with robustly detected infrared absorption features (>10{sigma})-there is no reliable way to tell from the transmission spectrum whether the absorber is a main constituent of the atmosphere or just a minor species with a mixing ratio of X{sub abs} < 0.1%. The retrieval method leads us to a

  16. 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.

  17. The Impact of Energetic Particle Precipitation on the Earths Atmosphere

    NASA Astrophysics Data System (ADS)

    Funke, B.; López-Puertas, M.; García-Comas, M.; Bermejo-Pantaleón, D.; Stiller, G. P.; von Clarmann, T.

    Energetic particle precipitation (EPP) represents an important Sun-Earth coupling mechanism with important implications on polar stratospheric ozone chemistry. Solar protons generated during solar storms cause sporadically in situ production of stratospheric NO x and HO x radicals involved in catalytic ozone destruction. Further, NO produced continuously in the mesosphere and lower thermosphere by medium energy electron precipitation (EEP) descends to the stratosphere during the polar winter, where it represents an additional, though variable source of NO x . The capability of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) to measure all important NO y species, as well as ClO and HOCl with global coverage including the polar night regions make it an ideal instrument for studying EPP effects on stratospheric chemistry. We present a quantitative assessment of EPP-induced composition changes as observed by MIPAS during 2002-2004, including the unusually strong solar proton event in October/November 2003. The impact of EPP on the stratospheric ozone budget has been studied with chemical models. The stratospheric ozone loss in the polar regions reached 18DU and lasted over months to years.

  18. The atmospheric excitation of earth orientation changes during MERIT

    NASA Technical Reports Server (NTRS)

    Eubanks, T. M.; Steppe, J. A.; Dickey, J. O.

    1986-01-01

    Geodetic estimates of earth orientation variations detected during the MERIT campaign (September 1983-November 1984) are compared with corresponding meteorological data. The geodetic data were obtained using VLBI, lunar laser ranging, and satellite laser ranging and the meteorological data were from the NMC in the U.S. and the European Centre for Medium Range Weather Forecasting (ECMRWF) in the U.K. The effects of changes in pressure, wind, and the inverted barometer ocean response on the excitation of the polar motion and the length of day are examined. The comparison between the meteorological and geodetic data reveals that the equatorial vector component of the atmospheric angular momentum (AAM) has significant annual and semiannual variations. Good correlation is detected between the geodetic polar motion data and the NMC pressure inverted barometer data combined with the ECMRWF wind estimates and semiannual agreement with the NMC pressure data is observed. There is also good correlation between the ECMRWF and NMC polar vector component of the AAM data and the geodetic length of day estimates, and good semiannual agreement with NMC pressure data is noted.

  19. Possible Nuclear Transmutation of Nitrogen in the Earth's Atmosphere

    NASA Astrophysics Data System (ADS)

    Fukuhara, Mikio

    2006-02-01

    An attempt to give a possible answer to a question why nitrogen exists so abundantly in Earth's atmosphere and how it was formed in Archean era (3.8-2.5 billion years ago) is presented. The nitrogen is postulated to be the result of an endothermic nuclear transmutation of carbon and oxygen nuclei confined in carbonate MgCO3 lattice of the mantle with an enhanced rate by attraction effect of catalysis of neutral pions, produced by electron emission: 12C + 16O - 2π0 → 2 14N. The excited electrons were generated by rapid fracture or sliding of carbonate crystals due to volcanic earthquake, and many of the neutrinos were derived from stars, mainly the young sun. The formation of nitrogen would continued for 1.3 billion years from 2.5 to 3.8 billion years in Archean era, until the active volcanism or storm of neutrinos ceased. The transformation is possible by the combined effects of the screening attraction of free electrons and thermal activation in deeper mantle. The possible nuclear transmutation rate of nitrogen atoms could be calculated as 2.3 × 106 atom/s.

  20. Runaway greenhouse atmospheres: Applications to Earth and Venus

    NASA Technical Reports Server (NTRS)

    Kasting, James F.

    1991-01-01

    Runaway greenhouse atmospheres are discussed from a theoretical standpoint and with respect to various practical situation in which they might occur. The following subject areas are covered: (1) runaway greenhouse atmospheres; (2) moist greenhouse atmospheres; (3) loss of water from Venus; (4) steam atmosphere during accretion; and (5) the continuously habitable zone.

  1. Oxidants and oxidation in the Earth`s atmosphere. Final technical report, 1 June 1994-30 May 1995

    SciTech Connect

    1995-02-01

    The 1994 BOC Priestley Conference was held at Bucknell University in Lewisburg, Pennsylvania, from June 24 through June 27, 1994. This conference, managed by the American Chemical Society (ACS), was a joint celebration with the Royal Society of Chemistry (RSC) commemorating Joseph Priestley`s arrival in the U.S. and his discovery of oxygen. The basic theme of the conference was `Oxidants and Oxidation in the Earth`s Atmosphere,` with a keynote lecture on the history of ozone. A distinguished group of U.S. and international atmospheric chemists addressed the issues dominating current research and policy agendas. Topics crucial to the atmospheric chemistry of global change and local and regional air pollution were discussed. The program for the conference included four technical sessions on the following topics: (1) Oxidative Fate of Atmospheric Pollutants; (2) Photochemical Smog and Ozone; (3) Stratospheric Ozone; and (4) Global Tropospheric Ozone.

  2. The atmospheres of the earth and the other planets: Origin, evolution and composition

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.

    1988-01-01

    The current understanding of the composition, chemistry, and structure of the atmospheres of the other planets and the origin, early history, and evolution of the earth's atmosphere is reviewed. The information on the atmospheres of the other planets is based on the successful Mariner, Viking, Pioneer, and Voyager missions to these planets. The information on the origin, early history, and evolution of the atmosphere, which is somewhat speculative, is largely based on numerical studies with geochemical and photochemical models.

  3. Massive impact-induced release of carbon and sulfur gases in the early Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Marchi, S.; Black, B. A.; Elkins-Tanton, L. T.; Bottke, W. F.

    2016-09-01

    Recent revisions to our understanding of the collisional history of the Hadean and early-Archean Earth indicate that large collisions may have been an important geophysical process. In this work we show that the early bombardment flux of large impactors (>100 km) facilitated the atmospheric release of greenhouse gases (particularly CO2) from Earth's mantle. Depending on the timescale for the drawdown of atmospheric CO2, the Earth's surface could have been subject to prolonged clement surface conditions or multiple freeze-thaw cycles. The bombardment also delivered and redistributed to the surface large quantities of sulfur, one of the most important elements for life. The stochastic occurrence of large collisions could provide insights on why the Earth and Venus, considered Earth's twin planet, exhibit radically different atmospheres.

  4. Challenges of Using Earth's Atmosphere as a Proxy for Detecting Biosignatures on Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    DeMarines, J.

    2012-06-01

    Assessing the challenges associated with the detectability of primitive biosignatures present on early Earth (methane and ethane) and addressing the observational difficulties when we begin to observe extrasolar atmospheres with a TPF-O mission.

  5. Lightning-made Waves in Earth's Atmosphere Leak Into Space

    NASA Video Gallery

    As lightning flashes, it creates low frequency waves that circle Earth, a phenomenon known as Schumann resonance. Much of the energy from the waves is trapped between the ground and the ionosphere ...

  6. Earth curvature and atmospheric refraction effects on radar signal propagation.

    SciTech Connect

    Doerry, Armin Walter

    2013-01-01

    The earth isn't flat, and radar beams don't travel straight. This becomes more noticeable as range increases, particularly at shallow depression/grazing angles. This report explores models for characterizing this behavior.

  7. Modeling of atmospheric-coupled Rayleigh waves on planets with atmosphere: From Earth observation to Mars and Venus perspectives.

    PubMed

    Lognonné, Philippe; Karakostas, Foivos; Rolland, Lucie; Nishikawa, Yasuhiro

    2016-08-01

    Acoustic coupling between solid Earth and atmosphere has been observed since the 1960s, first from ground-based seismic, pressure, and ionospheric sensors and since 20 years with various satellite measurements, including with global positioning system (GPS) satellites. This coupling leads to the excitation of the Rayleigh surface waves by local atmospheric sources such as large natural explosions from volcanoes, meteor atmospheric air-bursts, or artificial explosions. It contributes also in the continuous excitation of Rayleigh waves and associated normal modes by atmospheric winds and pressure fluctuations. The same coupling allows the observation of Rayleigh waves in the thermosphere most of the time through ionospheric monitoring with Doppler sounders or GPS. The authors review briefly in this paper observations made on Earth and describe the general frame of the theory enabling the computation of Rayleigh waves for models of telluric planets with atmosphere. The authors then focus on Mars and Venus and give in both cases the atmospheric properties of the Rayleigh normal modes and associated surface waves compared to Earth. The authors then conclude on the observation perspectives especially for Rayleigh waves excited by atmospheric sources on Mars and for remote ionospheric observations of Rayleigh waves excited by quakes on Venus. PMID:27586770

  8. Atmosphere, ocean, and land: Critical gaps in Earth system models

    NASA Technical Reports Server (NTRS)

    Prinn, Ronald G.; Hartley, Dana

    1992-01-01

    We briefly review current knowledge and pinpoint some of the major areas of uncertainty for the following fundamental processes: (1) convection, condensation nuclei, and cloud formation; (2) oceanic circulation and its coupling to the atmosphere and cryosphere; (3) land surface hydrology and hydrology-vegetation coupling; (4) biogeochemistry of greenhouse gases; and (5) upper atmospheric chemistry and circulation.

  9. Climatic consequences of very high carbon dioxide levels in the earth's early atmosphere.

    PubMed

    Kasting, J F; Ackerman, T P

    1986-12-12

    The possible consequences of very high carbon dioxide concentrations in the earth's early atmosphere have been investigated with a radiative-convective climate model. The early atmosphere would apparently have been stable against the onset of a runaway greenhouse (that is, the complete evaporation of the oceans) for carbon dioxide pressures up to at least 100 bars. A 10- to 20-bar carbon dioxide atmosphere, such as may have existed during the first several hundred million years of the earth's history, would have had a surface temperature of approximately 85 degrees to 110 degrees C. The early stratosphere should have been dry, thereby precluding the possibility of an oxygenic prebiotic atmosphere caused by photodissociation of water vapor followed by escape of hydrogen to space. Earth's present atmosphere also appears to be stable against a carbon dioxide-induced runaway greenhouse. PMID:11539665

  10. 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.

  11. L2 Earth atmosphere observatory : formation guidance, metrology, and control synthesis

    NASA Technical Reports Server (NTRS)

    Acikmese, Behcet A.; Mettler, Edward; Breckenridge, William G.; Macenka, Steven A.; Tubbs, Eldred F.

    2004-01-01

    This paper discusses the results of research sponsored by the NASA Revolutionary Aerospace Systems Concepts (RASC) program, and includes the synthesis and analysis of the guidance, metrology and control for a two-spacecraft formation in a unique continuously powered orbit near the Sun-Earth L2 Lagrange point observing the illuminated atmosphere of the Earth while it is continuously occulting the Sun.

  12. Determining How Atmospheric Carbon Dioxide Concentrations Have Changed during the History of the Earth

    ERIC Educational Resources Information Center

    Badger, Marcus P. S.; Pancost, Richard D.; Harrison, Timothy G.

    2011-01-01

    The reconstruction of ancient atmospheric carbon dioxide concentrations is essential to understanding the history of the Earth and life. It is also an important guide to identifying the sensitivity of the Earth system to this greenhouse gas and, therefore, constraining its future impact on climate. However, determining the concentration of…

  13. Impact of atmospheric refraction: how deeply can we probe exo-earth's atmospheres during primary eclipse observations?

    SciTech Connect

    Bétrémieux, Yan; Kaltenegger, Lisa

    2014-08-10

    Most models used to predict or fit exoplanet transmission spectra do not include all the effects of atmospheric refraction. Namely, the angular size of the star with respect to the planet can limit the lowest altitude, or highest density and pressure, probed during primary eclipses as no rays passing below this critical altitude can reach the observer. We discuss this geometrical effect of refraction for all exoplanets and tabulate the critical altitude, density, and pressure for an exoplanet identical to Earth with a 1 bar N{sub 2}/O{sub 2} atmosphere as a function of both the incident stellar flux (Venus, Earth, and Mars-like) at the top of the atmosphere and the spectral type (O5-M9) of the host star. We show that such a habitable exo-Earth can be probed to a surface pressure of 1 bar only around the coolest stars. We present 0.4-5.0 μm model transmission spectra of Earth's atmosphere viewed as a transiting exoplanet, and show how atmospheric refraction modifies the transmission spectrum depending on the spectral type of the host star. We demonstrate that refraction is another phenomenon that can potentially explain flat transmission spectra over some spectral regions.

  14. Photochemistry in terrestrial exoplanet atmospheres. III. Photochemistry and thermochemistry in thick atmospheres on super Earths and mini Neptunes

    SciTech Connect

    Hu, Renyu; Seager, Sara

    2014-03-20

    Some super Earths and mini Neptunes will likely have thick atmospheres that are not H{sub 2}-dominated. We have developed a photochemistry-thermochemistry kinetic-transport model for exploring the compositions of thick atmospheres on super Earths and mini Neptunes, applicable for both H{sub 2}-dominated atmospheres and non-H{sub 2}-dominated atmospheres. Using this model to study thick atmospheres for wide ranges of temperatures and elemental abundances, we classify them into hydrogen-rich atmospheres, water-rich atmospheres, oxygen-rich atmospheres, and hydrocarbon-rich atmospheres. We find that carbon has to be in the form of CO{sub 2} rather than CH{sub 4} or CO in a H{sub 2}-depleted water-dominated thick atmosphere and that the preferred loss of light elements from an oxygen-poor carbon-rich atmosphere leads to the formation of unsaturated hydrocarbons (C{sub 2}H{sub 2} and C{sub 2}H{sub 4}). We apply our self-consistent atmosphere models to compute spectra and diagnostic features for known transiting low-mass exoplanets GJ 1214 b, HD 97658 b, and 55 Cnc e. For GJ 1214 b, we find that (1) C{sub 2}H{sub 2} features at 1.0 and 1.5 μm in transmission and C{sub 2}H{sub 2} and C{sub 2}H{sub 4} features at 9-14 μm in thermal emission are diagnostic for hydrocarbon-rich atmospheres; (2) a detection of water-vapor features and a confirmation of the nonexistence of methane features would provide sufficient evidence for a water-dominated atmosphere. In general, our simulations show that chemical stability has to be taken into account when interpreting the spectrum of a super Earth/mini Neptune. Water-dominated atmospheres only exist for carbon to oxygen ratios much lower than the solar ratio, suggesting that this kind of atmospheres could be rare.

  15. What can we learn by comparing Earth and Titan's upper atmospheres?

    NASA Astrophysics Data System (ADS)

    Galand, M.; Yelle, R.; Coates, A.; Cunningham, E.; Dougherty, M.

    2006-05-01

    The Saturnian moon, Titan, is the only moon in the Solar System to sustain a dense, permanent atmosphere. Its dominant atmospheric constituent, molecular nitrogen, is a major species in the terrestrial atmosphere. Earth and Titan also share a similar obliquity (near 25 degrees) yielding season cycle and a similar surface pressure (of the order of one bar). Bearing in mind this common basis, differences in distance from the Sun, in forcing from the magnetized environment and from below, in atmospheric composition (molecular nitrogen apart), and in gravity make a comparison of Earth and Titan's upper atmospheres a very relevant and constructive undertaking. Is Titan's atmosphere "just" colder than the present terrestrial atmosphere? We will present a quantitative comparison of Earth and Titan's upper atmospheres in the context of the Cassini/TA flyby. In particular, we will focus on the contribution of solar forcing and induced photoelectron flux to the upper atmospheres of both bodies. The contribution of various energy sources to Titan's upper atmosphere will be derived from comparison of modelling results against Cassini/CAPS plasma observations.

  16. Kinetic Monte Carlo models for the study of chemical reactions in the Earth's upper atmosphere

    NASA Astrophysics Data System (ADS)

    Turchak, L. I.; Shematovich, V. I.

    2016-06-01

    A stochastic approach to study the non-equilibrium chemistry in the Earth's upper atmosphere is presented, which has been developed over a number of years. Kinetic Monte Carlo models based on this approach are an effective tool for investigating the role of suprathermal particles both in local variations of the atmospheric chemical composition and in the formation of the hot planetary corona.

  17. Advancing Solid Earth Science through Improved Atmosphere Modeling

    NASA Technical Reports Server (NTRS)

    Niell, A. E.

    2004-01-01

    We proposed to investigate and develop better models for the effect of the hydrostatic and water vapor components of the neutral atmosphere on delay for VLBI and GPS by using a Numerical Weather Model to better simulate realistic atmosphere conditions. By using a raytrace calculation through the model atmosphere at the times of actual VLBI observations, the potential improvement in geodetic results can be evaluated. Also, by calculating the actual variation of delays with elevation and azimuth, the errors in current mapping function models can be assessed. The VLBI data to be initially analyzed are the fifteen days of the CONT02 sessions of 2002 October which included eight stations. There are three segments to the research. 1) The PSU/NCAR fifth generation mesoscale numerical weather model (MM5) will be used to provide the state of the atmosphere with highest horizontal resolution of 3 km. 2) A three-dimensional raytrace program will be developed to determine the delays through the model atmosphere at the times and in the directions of the VLBI observations for each of the sites. 3) The VLBI data will be analyzed using both standard models for the atmosphere mapping functions and the mapping functions derived from the NWM raytracing.

  18. The atmospheric circulation of the super Earth GJ 1214b: Dependence on composition and metallicity

    SciTech Connect

    Kataria, T.; Showman, A. P.; Fortney, J. J.; Marley, M. S.; Freedman, R. S.

    2014-04-20

    We present three-dimensional atmospheric circulation models of GJ 1214b, a 2.7 Earth-radius, 6.5 Earth-mass super Earth detected by the MEarth survey. Here we explore the planet's circulation as a function of atmospheric metallicity and atmospheric composition, modeling atmospheres with a low mean molecular weight (MMW; i.e., H{sub 2}-dominated) and a high MMW (i.e., water- and CO{sub 2}-dominated). We find that atmospheres with a low MMW have strong day-night temperature variations at pressures above the infrared photosphere that lead to equatorial superrotation. For these atmospheres, the enhancement of atmospheric opacities with increasing metallicity lead to shallower atmospheric heating, larger day-night temperature variations, and hence stronger superrotation. In comparison, atmospheres with a high MMW have larger day-night and equator-to-pole temperature variations than low MMW atmospheres, but differences in opacity structure and energy budget lead to differences in jet structure. The circulation of a water-dominated atmosphere is dominated by equatorial superrotation, while the circulation of a CO{sub 2}-dominated atmosphere is instead dominated by high-latitude jets. By comparing emergent flux spectra and light curves for 50× solar and water-dominated compositions, we show that observations in emission can break the degeneracy in determining the atmospheric composition of GJ 1214b. The variation in opacity with wavelength for the water-dominated atmosphere leads to large phase variations within water bands and small phase variations outside of water bands. The 50× solar atmosphere, however, yields small variations within water bands and large phase variations at other characteristic wavelengths. These observations would be much less sensitive to clouds, condensates, and hazes than transit observations.

  19. The Atmospheric Circulation of the Super Earth GJ 1214b: Dependence on Composition and Metallicity

    NASA Astrophysics Data System (ADS)

    Kataria, T.; Showman, A. P.; Fortney, J. J.; Marley, M. S.; Freedman, R. S.

    2014-04-01

    We present three-dimensional atmospheric circulation models of GJ 1214b, a 2.7 Earth-radius, 6.5 Earth-mass super Earth detected by the MEarth survey. Here we explore the planet's circulation as a function of atmospheric metallicity and atmospheric composition, modeling atmospheres with a low mean molecular weight (MMW; i.e., H2-dominated) and a high MMW (i.e., water- and CO2-dominated). We find that atmospheres with a low MMW have strong day-night temperature variations at pressures above the infrared photosphere that lead to equatorial superrotation. For these atmospheres, the enhancement of atmospheric opacities with increasing metallicity lead to shallower atmospheric heating, larger day-night temperature variations, and hence stronger superrotation. In comparison, atmospheres with a high MMW have larger day-night and equator-to-pole temperature variations than low MMW atmospheres, but differences in opacity structure and energy budget lead to differences in jet structure. The circulation of a water-dominated atmosphere is dominated by equatorial superrotation, while the circulation of a CO2-dominated atmosphere is instead dominated by high-latitude jets. By comparing emergent flux spectra and light curves for 50× solar and water-dominated compositions, we show that observations in emission can break the degeneracy in determining the atmospheric composition of GJ 1214b. The variation in opacity with wavelength for the water-dominated atmosphere leads to large phase variations within water bands and small phase variations outside of water bands. The 50× solar atmosphere, however, yields small variations within water bands and large phase variations at other characteristic wavelengths. These observations would be much less sensitive to clouds, condensates, and hazes than transit observations.

  20. Greenhouse warming by CH4 in the atmosphere of early Earth.

    PubMed

    Pavlov, A A; Kasting, J F; Brown, L L; Rages, K A; Freedman, R

    2000-05-25

    Earth appears to have been warm during its early history despite the faintness of the young Sun. Greenhouse warming by gaseous CO2 and H2O by itself is in conflict with constraints on atmospheric CO2 levels derived from paleosols for early Earth. Here we explore whether greenhouse warming by methane could have been important. We find that a CH4 mixing ratio of 10(-4) (100 ppmv) or more in Earth's early atmosphere would provide agreement with the paleosol data from 2.8 Ga. Such a CH4 concentration could have been readily maintained by methanogenic bacteria, which are thought to have been an important component of the biota at that time. Elimination of the methane component of the greenhouse by oxidation of the atmosphere at about 2.3-2.4 Ga could have triggered the Earth's first widespread glaciation. PMID:11543544

  1. On the abundances of carbon dioxide isotopologues in the atmospheres of mars and earth

    NASA Astrophysics Data System (ADS)

    Shved, G. M.

    2016-03-01

    The isotopic composition of carbon dioxide in the Martian atmosphere from the measurements of Mars Science Laboratory have been used to estimate the relative abundances of CO2 isotopologues in the Martian atmosphere. Concurrently, this study has revealed long-standing errors in the amounts of some of low-abundance CO2 isotopologues in the Earth's atmosphere in the databases of spectroscopic parameters of gases (HITRAN, etc.).

  2. Atmospheric Correction Prototype Algorithm for High Spatial Resolution Multispectral Earth Observing Imaging Systems

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary

    2006-01-01

    This viewgraph presentation reviews the creation of a prototype algorithm for atmospheric correction using high spatial resolution earth observing imaging systems. The objective of the work was to evaluate accuracy of a prototype algorithm that uses satellite-derived atmospheric products to generate scene reflectance maps for high spatial resolution (HSR) systems. This presentation focused on preliminary results of only the satellite-based atmospheric correction algorithm.

  3. X-38: Artist Concept of Re-Entering Earth's Atmosphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This is an artist's depiction of NASA's proposed Crew Return Vehicle (CRV) re-entering the earth's atmosphere. A team of NASA researchers began free flight tests of the X-38, a technology demonstrator for the CRV, at NASA's Dryden Flight Research Center, Edwards, California, in 1998. The CRV is being designed as a 'lifeboat' for the International Space Station The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle, or lifeboat, for the International Space Station. The project is also intended to develop a crew return vehicle design that could be modified for other uses, such as a joint U.S. and international human spacecraft that could be launched on the French Ariane-5 Booster. The X-38 project is using available technology and off-the-shelf equipment to significantly decrease development costs. Original estimates to develop a capsule-type crew return vehicle were estimated at more than $2 billion. X-38 project officials have estimated that development costs for the X-38 concept will be approximately one quarter of the original estimate. Off-the-shelf technology is not necessarily 'old' technology. Many of the technologies being used in the X-38 project have never before been applied to a human-flight spacecraft. For example, the X-38 flight computer is commercial equipment currently used in aircraft and the flight software operating system is a commercial system already in use in many aerospace applications. The video equipment for the X-38 is existing equipment, some of which has already flown on the space shuttle for previous NASA experiments. The X-38's primary navigational equipment, the Inertial Navigation System/Global Positioning System, is a unit already in use on Navy fighters. The X-38 electromechanical actuators come from previous joint NASA, U.S. Air Force, and U.S. Navy research and development projects. Finally, an existing special coating developed by NASA will be used

  4. Analysis of longwave radiation for the Earth-atmosphere system

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Venuru, C. S.; Subramanian, S. V.

    1983-01-01

    Accurate radiative transfer models are used to determine the upwelling atmospheric radiance and net radiative flux in the entire longwave spectral range. The validity of the quasi-random band model is established by comparing the results of this model with those of line-by-line formulations and with available theoretical and experimental results. Existing radiative transfer models and computer codes are modified to include various surface and atmospheric effects (surface reflection, nonequilibrium radiation, and cloud effects). The program is used to evaluate the radiative flux in clear atmosphere, provide sensitivity analysis of upwelling radiance in the presence of clouds, and determine the effects of various climatological parameters on the upwelling radiation and anisotropic function. Homogeneous and nonhomogeneous gas emissivities can also be evaluated under different conditions.

  5. Evaluation of upwelling infrared radiance from earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Gupta, S. K.; Tiwari, S. N.

    1975-01-01

    Basic equations for calculating the upwelling atmospheric radiation are presented which account for various sources of radiation coming out at the top of the atmosphere. The theoretical formulation of the transmittance models (line-by-line and quasi-random band model) and the computational procedures used for the evaluation of the transmittance and radiance are discussed in detail. By employing the Lorentz line-by-line and quasi-random computer programs, model calculations were made to determine the upwelling radiance and signal change in the wave number interval of CO fundamental band. These results are useful in determining the effects of different interfering molecules, water vapor profiles, ground temperatures, and ground emittances on the upwelling radiance and signal change. This information is of vital importance in establishing the feasibility of measuring the concentrations of pollutants in the atmosphere from a gas filter correlation instrument flown on an aircraft or mounted on a satellite.

  6. Atmospheric Infrared Sounder on the Earth Observing System

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.

    1995-01-01

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

  7. Nonlinear dynamics of global atmospheric and Earth-system processes

    NASA Technical Reports Server (NTRS)

    Saltzman, Barry; Ebisuzaki, Wesley; Maasch, Kirk A.; Oglesby, Robert; Pandolfo, Lionel

    1991-01-01

    General Circulation Model (GCM) studies of the atmospheric response to change boundary conditions are discussed. Results are reported on an extensive series of numerical studies based on the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM) general circulation model. In these studies the authors determined the response to systematic changes in atmospheric CO2 ranging from 100 to 1000 ppm; to changes in the prescribed sea surface temperature (SST) in the Gulf of Mexico, such as occurred during the deglaciation phase of the last ice age; to changes in soil moisture over North America; and to changes in sea ice extent in the Southern Hemisphere. Study results show that the response of surface temperature and other variables is nearly logarithmic, with lower levels of CO2 implying greater sensitivity of the atmospheric state to changes in CO2. It was found that the surface temperature of the Gulf of Mexico exerts considerable control over the storm track and behavior of storm systems over the North Atlantic through its influence on evaporation and the source of latent heat. It was found that reductions in soil moisture can play a significant role in amplifying and maintaining North American drought, particularly when a negative soil moisture anomaly prevails late in the spring.

  8. Models of earth's atmosphere (90 to 2500 km)

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This monograph replaces a monograph on the upper atmosphere which was a computerized version of Jacchia's model. The current model has a range from 90 to 2500 km. In addition to the computerized model, a quick-look prediction method is given that may be used to estimate the density for any time and spatial location without using a computer.

  9. Comparing atmospheric chemical disequilibrium of Earth and Mars to detect the traces of Life

    NASA Astrophysics Data System (ADS)

    Simoncini, Eugenio; Brucato, John Robert; Grassi, Tommaso

    Thanks to rover explorations, satellite mapping and in loco measurements, there are many evidence nowadays that early Mars could have hold extended oceans of liquid water. This makes early Mars similar to early Earth, and a deeper understanding of the conditions which led to the emergence of Life on Earth is needed. It has long been observed that Earth's atmosphere is uniquely far from its thermochemical equilibrium state in terms of its chemical composition. Studying this state of disequilibrium is important for its potential role in the detection of life on other suitable planets [1][2][3]. We developed a methodology to calculate the extent of atmospheric chemical disequilibrium [3][4]. This tool allows us to understand, on a thermodynamic basis, how life affected - and still affects - geochemical processes on Earth, and if other planetary atmospheres are habitable or have a disequilibrium similar to the Earth's one. A new computational framework called KROME has been applied to atmospheric models in order to give a correct computation of reactionś kinetics [5]. In this work we present a first computation of the extent of disequilibrium for the present and early Earth and Mars atmospheres, considering the specific contribution of the different atmospheric processes, such as thermochemical reactions, eddy diffusion, photochemistry, deposition, and the effect of the biosphere. We then assess the effect of life on atmospheric disequilibrium of the Earth and provide a comparison between “alive” and “dead” Earth, present and (plausible) early Mars. Our results provide a comprehensive analysis of atmospheric disequilibrium for rocky and habitable planets, which can be also used for the detection of habitable conditions on farther planetary bodies. [1] Lovelock, J. E.: A physical basis for life detection experiments, Nature, 207, 568 (1965) [2] Kleidon, A., Physics of Life Reviews, 7, 424 (2010) [3] Simoncini E., Grassi T., Disequilibrium in planetary

  10. Secondary Cosmic Ray Particles Due to GCR Interactions in the Earth's Atmosphere

    SciTech Connect

    Battistoni, G.; Cerutti, F.; Fasso, A.; Ferrari, A.; Garzelli, M.V.; Lantz, M.; Muraro, S. Pinsky, L.S.; Ranft, J.; Roesler, S.; Sala, P.R.; /Milan U. /INFN, Milan

    2009-06-16

    Primary GCR interact with the Earth's atmosphere originating atmospheric showers, thus giving rise to fluxes of secondary particles in the atmosphere. Electromagnetic and hadronic interactions interplay in the production of these particles, whose detection is performed by means of complementary techniques in different energy ranges and at different depths in the atmosphere, down to the Earth's surface. Monte Carlo codes are essential calculation tools which can describe the complexity of the physics of these phenomena, thus allowing the analysis of experimental data. However, these codes are affected by important uncertainties, concerning, in particular, hadronic physics at high energy. In this paper we shall report some results concerning inclusive particle fluxes and atmospheric shower properties as obtained using the FLUKA transport and interaction code. Some emphasis will also be given to the validation of the physics models of FLUKA involved in these calculations.

  11. Atmospheric radiative transfer generalised for use on Earth and other planets: ARTS 2.2

    NASA Astrophysics Data System (ADS)

    Mendrok, Jana; Eriksson, Patrick; Buehler, Stefan; Perrin, Agnes; Hartogh, Paul; Rezac, Ladislav; Lemke, Oliver

    2015-04-01

    Microwave and (sub)millimetre-wave frequencies have long been of interest for remote sensing of the Earth and space objects. They suffer less from interference by small particles (dust, clouds), hence penetrate deeper into atmospheres revealing their deeper structures hidden to shorter wavelengths, and possess characteristic line absorption features of many gaseous species, which are of interest for the understanding of atmospheric chemistry and dynamics. Models simulating radiative transfer and wave propagation (RT/WP) have been developed by many institutions. Most of them are designed for a particular, narrow region of the electromagnetic spectrum, certain instrument types or missions, and specific atmospheric conditions. In particular, they are usually set up for a specific planetary body. This high level of specialisation allows for accurate modelling results. However, it also limits the flexibility of those models and comparability between them. One of the major differences in radiative transfer modeling in the atmospheres of Earth and other planets arises from the different composition of the atmospheres. When interested in measuring total abundance or even vertical distribution of atmospheric constituents, knowledge of parameters describing spectrally dependent absorption in dependence of atmospheric state is required. When modeling radiative transfer for different planets, the line shapes are often accounted for by scaling the parameters valid for Earth's ``air'' or by building a spectroscopic catalogue specific to the planet in question and its main atmospheric composition. This strongly limits applicability of these models. Based on the ARTS model [1], a sophisticated, flexible RT model for Earth atmosphere (3D spherical geometry, diverse absorption models, scattering, polarization, Jacobians), we have developed a toolbox for microwave atmospheric radiative transfer in solar system planets. As part of this, we developed and implemented a more generalized

  12. NASA's Earth Observing System (EOS): Observing the Atmosphere, Land, Oceans, and Ice from Space

    NASA Technical Reports Server (NTRS)

    King, Michael D.

    2005-01-01

    The Earth Observing System (EOS) is a space-based observing system comprised of a series of satellite sensors by whch scientists can monitor the Earth, a Data and Information System (EOSDIS) enabling researchers worldwide to access the satellite data, and an interdisciplinary science research program to interpret the satellite data. During this year, the last of the first series of EOS missions, Aura, was launched. Aura is designed exclusively to conduct research on the composition, chemistry, and dynamics of the Earth's upper and lower atmosphere, employing multiple instruments on a single spacecraft. Aura is the third in a series of major Earth observing satellites to study the environment and climate change and is part of NASA's Earth Science Enterprise. The first and second missions, Terra and Aqua, are designed to study the land, oceans, atmospheric constituents (aerosols, clouds, temperature, and water vapor), and the Earth's radiation budget. The other seven EOS spacecraft include satellites to study (i) land cover & land use change, (ii) solar irradiance and solar spectral variation, (iii) ice volume, (iv) ocean processes (vector wind and sea surface topography), and (v) vertical variations of clouds, water vapor, and aerosols up to and including the stratosphere. Aura's chemistry measurements will also follow up on measurements that began with NASA's Upper Atmosphere Research Satellite and continue the record of satellite ozone data collected from the TOMS missions. In this presentation I will describe how scientists are using EOS data to examine the health of the earth's atmosphere, including atmospheric chemistry, aerosol properties, and cloud properties, with a special look at the latest earth observing mission, Aura.

  13. NASA's Earth Observing System (EOS): Observing the Atmosphere, Land, Oceans, and Ice from Space

    NASA Technical Reports Server (NTRS)

    King, Michael D.

    2004-01-01

    The Earth Observing System (EOS) is a space-based observing system comprised of a series of satellite sensors by which scientists can monitor the Earth, a Data and Information System (EOSDIS) enabling researchers worldwide to access the satellite data, and an interdisciplinary science research program to interpret the satellite data. During this year, the last of the first series of EOS missions, Aura, was launched. Aura is designed exclusively to conduct research on the composition, chemistry, and dynamics of the Earth's upper and lower atmosphere, employing multiple instruments on a single spacecraft. Aura is the third in a series of major Earth observing satellites to study the environment and climate change and is part of NASA's Earth Science Enterprise. The first and second missions, Terra and Aqua, are designed to study the land, oceans, atmospheric constituents (aerosols, clouds, temperature, and water vapor), and the Earth's radiation budget. The other seven EOS spacecraft include satellites to study (i) land cover & land use change, (ii) solar irradiance and solar spectral variation, (iii) ice volume, (iv) ocean processes (vector wind and sea surface topography), and (v) vertical variations of clouds, water vapor, and aerosols up to and including the stratosphere. Aura's chemistry measurements will also follow up on measurements that began with NASA's Upper Atmosphere Research Satellite and continue the record of satellite ozone data collected from the TOMS missions. In this presentation I will describe how scientists are using EOS data to examine the health of the earth's atmosphere, including atmospheric chemistry, aerosol properties, and cloud properties, with a special but not exclusive look at the latest earth observing mission, Aura.

  14. Hydrogen and climate in primitive terrestrial and super-Earth atmospheres (Invited)

    NASA Astrophysics Data System (ADS)

    Wordsworth, R.

    2013-12-01

    For the three terrestrial planets with significant atmospheres in the Solar System (Earth, Venus and Mars), present-day conditions are oxidizing, with combinations of CO2, N2, O2 and H2O dominating by mass and in terms of the greenhouse effect. However, primitive terrestrial or ';super-Earth' exoplanet atmospheres may be much more reducing (i.e., hydrogen-rich), with major implications for climate, composition, and pre-biotic chemistry. Here I discuss recent work on the role of hydrogen in terrestrial planetary atmospheres, with a particular focus on the early Earth. I describe how collision-induced absorption (CIA) by hydrogen may have significantly warmed Earth's surface in the Archean and Hadean by blocking the critical water vapour absorption window at 800-1200 cm-1. This warming may have helped mitigate the faint young Sun effect early on. After the emergence of widespread methanogenesis, the consumption of H2 and CO2 should have led to a global shift in climate, with potentially observable consequences in the geological record. Because of variations in planetary mass, stellar XUV input and outgassing rates, hydrogen is also likely to be an important component of many super-Earth atmospheres. As I will discuss, this should have a significant effect on climate evolution and the carbon cycle on such planets, which should be considered in future predictions of atmospheric spectra and biosignatures.

  15. The oxygen and carbon dioxide balance in the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Johnson, F. S.

    1975-01-01

    The oxygen-carbon dioxide cycle is described in detail, and steps which are sensitive to perturbation or instability are identified. About half of the carbon dioxide consumption each year in photosynthesis occurs in the oceans. Phytoplankton, which are the primary producers, have been shown to assimilate insecticides and herbicides. The impact of such materials on phytoplankton photosynthesis, both direct and as the indirect result of detrimental effects higher up in the food chain, cannot be assessed. Net oxygen production is very small in comparison with the total production and occurs almost exclusively in a few ocean areas with anoxic bottom conditions and in peat-forming marshes which are sensitive to anthropogenic disturbances. The carbon dioxide content of the atmosphere is increasing at a relatively rapid rate as the result of fossil fuel combustion. Increases in photosynthesis as the result of the hothouse effect may in turn reduce the carbon dioxide content of the atmosphere, leading to global cooling.

  16. Advanced sensors for spaceborne measurements of the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Hinkley, E. D.

    1982-01-01

    Concepts involved in remote sensing from space are reviewed, together with performance requirements of proposed and planned equipment. Attention is focused on measurements of the troposphere, particularly meteorological variables and chemical species. The principles of absorption, using either passive or active sensors, emission detection, fluorescence measurements, and EM radiation scattering are outlined. The proposed NASA Windsat, using a CO2 laser from the Orbiter or from an 800 km orbit spacecraft to measure low-level wind speeds is described, as are the uses of the AMTS atmospheric sounder instrument for IR atmospheric temperature sensing and a 20-channel microwave radiometer to detect moisture profiles in the water vapor bands. Additionally, a microwave pressure sounder to detect backscattered signals at 60 GHz is outlined, along with lidar pressure and wind speed measurement methods.

  17. Revised Atmospheric Angular Momentum Series Related to Earth's Variable Rotation under Consideration of Surface Topography

    NASA Technical Reports Server (NTRS)

    Zhou, Y. H.; Salstein, D. A.; Chen, J. L.

    2006-01-01

    The atmospheric angular momentum is closely related to variations in the Earth rotation. The atmospheric excitation function (AEF), or namely atmospheric effective angular momentum function, is introduced in studying the atmospheric excitation of the Earth's variable rotation. It may be separated into two portions, i.e, the "wind" terms due to the atmospheric motion relative to the mantle and the "pressure" terms due to the variations of atmospheric mass distribution evident through surface pressure changes. The AEF wind terms during the period of 1948-2004 are re-processed from the NCEP/NCAR (National Centers for Environmental Prediction-National Center for Atmospheric Research) reanalysis 6-hourly wind and pressure fields. Some previous calculations were approximate, in that the wind terms were integrated from an isobaric lower boundary of 1000 hPa. To consider the surface topography effect, however, the AEF is computed by integration using the winds from the Earth's surface to 10 hPa, the top atmospheric model level, instead of from 1000 hPa. For these two cases, only a minor difference, equivalent to approx. 0.004 milliseconds in length-of-day variation, exists with respect to the axial wind term. However, considerable differences, equivalent to 5-6 milliarcseconds in polar motion, are found regarding equatorial wind terms. We further compare the total equatorial AEF (with and without the topographic effect) with the polar motion excitation function (PMEF) during the period of 1980-2003. The equatorial AEF gets generally closer to the PMEF, and improved coherences are found between them when the topography effect is included. Keywords: Atmospheric angular momentum, Atmospheric excitation function, Earth rotation, Topography, Wind, Pressure.

  18. Estimate of the 42Ar content in the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Barabash, A. S.; Kornoukhov, V. N.; Jants, V. E.

    1997-02-01

    42Ar is a potential source of background in large volume argon-based detectors. The production of the 42Ar isotope both by cosmic rays and by neutrons produced by testing of nuclear weapons is discussed. We demonstrate that main channel of the 42Ar production is from atmospheric testing of nuclear bombs from 1945 to 1962 and the 42Ar content must be less than 1.3 × 10 -23 parts of 42Ar per part of natAr.

  19. Three-dimensional random earth atmospheres for Monte Carlo trajectory analyses

    NASA Technical Reports Server (NTRS)

    Campbell, J. W.

    1977-01-01

    A set of four computer tapes containing random three dimensional Earth atmospheres is available for Monte Carlo trajectory analyses. The tapes contain sufficient atmospheric tables to allow replications of any trajectory below an altitude of 99 km. The atmospheres were provided by an empirical model designed to generate random atmospheres whose distributions match those in a data base of sounding rocket measurements. A readily implementable means of linking the tapes to any existing trajectory simulation computer program is described involving the addition of three subroutines which are listed in an appendix.

  20. Regional earth-atmosphere energy balance estimates based on assimilations with a GCM

    NASA Technical Reports Server (NTRS)

    Alexander, Michael A.; Schubert, Siegfried D.

    1990-01-01

    The Oort and Vonder Haar (1976) column-budget technique is presently used to evaluate the physical consistency and accuracy of regional earth-atmosphere energy balance estimates for (1) atmospheric budget terms, (2) net radiation at the top of the atmosphere, and (3) time tendency and flux divergence of energy, for Special Observing Periods of the FGGE year. It is found that, during winter, the midlatitude oceans supply large quantities of energy to the overlying atmosphere, which then transports the energy to the continental heat-sinks; the energy flows in the opposite direction during summer.

  1. Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth

    SciTech Connect

    Domagal-Goldman, Shawn D.; Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S.

    2014-09-10

    The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O{sub 2}) or ozone (O{sub 3}) simultaneous to methane (CH{sub 4}) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O{sub 2} and O{sub 3} production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O{sub 2} and O{sub 3} buildup, caused by fast chemical production of these gases. This results in detectable abiotic O{sub 3} and CH{sub 4} features in the UV-visible, but no detectable abiotic O{sub 2} features. Thus, simultaneous detection of O{sub 3} and CH{sub 4} by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O{sub 2} and O{sub 3} is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.

  2. CHClF2 /F-22/ in the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Rasmussen, R. A.; Khalil, M. A. K.; Penkett, S. A.; Prosser, N. J. D.

    1980-01-01

    Recent global measurements of CHClF2 (F-22) are reported. Originally, GC/MS techniques were used to obtain these data. Since then, significant advances using an O2-doped electron capture detector have been made in the analytical techniques, so that F-22 can be measured by EC/GC methods at ambient concentrations. The atmospheric burden of F-22 calculated from these measurements (average mixing ratio, mid-1979, approximately 45 pptv) is considerably greater than that expected from the estimates of direct industrial emissions (average mixing ratio, mid-1979, approximately 30 pptv). This difference is probably due to underestimates of F-22 emissions.

  3. CHClF2 (F-22) in the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Rasmussen, R. A.; Khalil, M. A. K.; Penkett, S. A.; Prosser, N. J. D.

    1980-10-01

    Recent global measurements of CHClF2 (F-22) are reported. Originally, GC/MS techniques were used to obtain these data. Since then, significant advances using an O2-doped electron capture detector have been made in the analytical techniques, so that F-22 can be measured by EC/GC methods at ambient concentrations. The atmospheric burden of F-22 calculated from these measurements (average mixing ratio, mid-1979, ˜45 pptv) is considerably greater than that expected from the estimates of direct industrial emissions (average mixing ratio, mid-1979, ˜30 pptv). This difference is probably due to underestimates of F-22 emissions.

  4. Ozone formation due to interaction of meteoroids with Earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Bibarsov, R. SH.

    1987-01-01

    In a previous paper, it was shown that concentration of atomic oxygen in overdense meteor trails may exceed that of the normal atmosphere by a factor of several hundred times. This may lead to the formation of meteoric ozone. Therefore, it is imperative to estimate the concentration of ozone in the trails of meteor bodies with different masses. It seems that meteoric ozone must be taken into account when studying the balance of ionization in the meteor trails formed by particles with masses more than .01 g. The predicted levels of atomic oxygen and ozone seem sufficient to greatly influence the rate of meteoric plasma deionization.

  5. Clouds in the atmosphere of the super-Earth exoplanet GJ 1214b.

    PubMed

    Kreidberg, Laura; Bean, Jacob L; Désert, Jean-Michel; Benneke, Björn; Deming, Drake; Stevenson, Kevin B; Seager, Sara; Berta-Thompson, Zachory; Seifahrt, Andreas; Homeier, Derek

    2014-01-01

    Recent surveys have revealed that planets intermediate in size between Earth and Neptune ('super-Earths') are among the most common planets in the Galaxy. Atmospheric studies are the next step towards developing a comprehensive understanding of this new class of object. Much effort has been focused on using transmission spectroscopy to characterize the atmosphere of the super-Earth archetype GJ 1214b (refs 7 - 17), but previous observations did not have sufficient precision to distinguish between two interpretations for the atmosphere. The planet's atmosphere could be dominated by relatively heavy molecules, such as water (for example, a 100 per cent water vapour composition), or it could contain high-altitude clouds that obscure its lower layers. Here we report a measurement of the transmission spectrum of GJ 1214b at near-infrared wavelengths that definitively resolves this ambiguity. The data, obtained with the Hubble Space Telescope, are sufficiently precise to detect absorption features from a high mean-molecular-mass atmosphere. The observed spectrum, however, is featureless. We rule out cloud-free atmospheric models with compositions dominated by water, methane, carbon monoxide, nitrogen or carbon dioxide at greater than 5σ confidence. The planet's atmosphere must contain clouds to be consistent with the data. PMID:24380954

  6. Earth atmospheric entry studies for manned Mars missions

    NASA Technical Reports Server (NTRS)

    Tauber, M. E.; Palmer, G. E.; Yang, Lily

    1990-01-01

    Decelerations, heating rates, and total heat loads encountered when returning from Mars to earth at entry speeds of 12 km/sec to 16 km/sec are studied. For entry at 14 km/sec, it is found that a lift/drag ratio (L/D) of 0.5 is required to provide a guidance corridor margin near 1 deg for the specified deceleration limit of 5 g. For a blunted, raked cone with an L/D = 0.5, the peak heating rate near the aft end of the forebody varies from 0.14 to 0.23 kW/sq cm for laminar flow. If ablation triggers boundary layer transition, the peak heating can rise to 0.5 or up to 0.72 kW/sq cm. All heating rates are sufficiently high to make ablative heat shields necessary.

  7. A statistical look at the retrieval of exoplanetary atmospheres of super Earths and giant planets

    NASA Astrophysics Data System (ADS)

    Rocchetto, Marco; Waldmann, Ingo Peter; Tinetti, Giovanna; Yurchenko, Sergey; Tennyson, Jonathan

    2015-08-01

    Over the past decades transit spectroscopy has become one of the pioneering methods to characterise exoplanetary atmospheres. With the increasing number of observations, and the advent of new ground and spaced based instruments, it is now crucial to find the most optimal and objective methodologies to interpret these data, and understand the information content they convey. This is particularly true for smaller and fainter super Earth type planets.In this conference we will present a new take on the spectral retrieval of transiting planets, with particular focus on super Earth atmospheres. TauREx (Waldmann et al. 2015a,b.) is a new line-by-line radiative transfer atmospheric retrieval framework for transmission and emission spectroscopy of exoplanetary atmospheres, optimised for hot Jupiters and super Earths. The code has been built from scratch with the ideas of scalability, flexibility and automation. This allows to run retrievals with minimum user input that can be scaled to large cluster computing. Priors on the number and types of molecules considered are automatically determined using a custom built pattern recognition algorithm able to identify the most likely absorbers/emitters in the exoplanetary spectra, minimising the human bias in selecting the major atmospheric constituents.Using these tools, we investigate the impact of signal to noise, spectral resolution and wavelength coverage on the retrievability of individual model parameters from transit spectra of super Earths, and put our models to test (Rocchetto et al. 2015). Characterisation of the atmospheres of super Earths through transit spectroscopy is paramount, as it can provide an indirect - and so far unique - way to probe the nature of these planets. For the first time we analyse in a systematic way large grids of spectra generated for different observing scenarios. We perform thousands of retrievals aimed to fully map the degeneracies and understand the statistics of current exoplanetary

  8. High-energy cosmic ray muons in the Earth's atmosphere

    SciTech Connect

    Kochanov, A. A.; Sinegovskaya, T. S.; Sinegovsky, S. I.

    2013-03-15

    We present the calculations of the atmospheric muon fluxes at energies 10-10{sup 7} GeV based on a numerical-analytical method for solving the hadron-nucleus cascade equations. It allows the non-power-law behavior of the primary cosmic ray (PCR) spectrum, the violation of Feynman scaling, and the growth of the total inelastic cross sections for hadron-nucleus collisions with increasing energy to be taken into account. The calculations have been performed for a wide class of hadron-nucleus interaction models using directly the PCR measurements made in the ATIC-2 and GAMMA experiments and the parameterizations of the primary spectrum based on a set of experiments. We study the dependence of atmospheric muon flux characteristics on the hadronic interaction model and the influence of uncertainties in the PCR spectrum and composition on the muon flux at sea level. Comparison of the calculated muon energy spectra at sea level with the data from a large number of experiments shows that the cross sections for hadron-nucleus interactions introduce the greatest uncertainty in the energy region that does not include the knee in the primary spectrum.

  9. Effects of atmospheric breakup on crater field formation. [on earth

    NASA Technical Reports Server (NTRS)

    Passey, Q. R.; Melosh, H. J.

    1980-01-01

    This paper investigates the physics of meteoroid breakup in the atmosphere and its implications for the observed features of strewn fields. There are several effects which cause dispersion of the meteoroid fragments: gravity, differential lift of the fragments, bow shock interaction just after breakup, centripetal separation by a rotating meteroid, and possibly a dynamical transverse separation resulting from the crushing deceleration in the atmosphere. Of these, it is shown that gravity alone can produce the common pattern in which the largest crater occurs at the downrange end of the scatter ellipse. The average lift-to-drag ratio of the tumbling fragments must be less than about 0.001, otherwise small fragments would produce small craters downrange of the main crater, and this is not generally observed. The cross-range dispersion is probably due to the combined effects of bow shock interaction, crushing deceleration, and possibly spinning of the meteoroid. A number of terrestrial strewn fields are discussed in the light of these ideas, which are formulated quantitatively for a range of meteoroid velocities, entry angles, and crushing strengths. It is found that when the crater size exceeds about 1 km, the separation between the fragments upon landing is a fraction of their own diameter, so that the crater formed by such a fragmented meteoroid is almost indistinguishable from that formed by a solid body of the same total mass and velocity.

  10. Earth Orientation and Its Excitations by Atmosphere, Oceans, and Geomagnetic Jerks

    NASA Astrophysics Data System (ADS)

    Vondrák, J.; Ron, C.

    2015-12-01

    In addition to torques exerted by the Moon, Sun, and planets, changes of the Earth orientation parameters (EOP) are known to be caused also by excitations by the atmosphere and oceans. Recently appeared studies, hinting that geomagnetic jerks (GMJ, rapid changes of geomagnetic field) might be associated with sudden changes of phase and amplitude of EOP (Holme and de Viron 2005, 2013, Gibert and Le Mouël 2008, Malkin 2013). We (Ron et al. 2015) used additional excitations applied at the epochs of GMJ to derive its influence on motion of the spin axis of the Earth in space (precession-nutation). We demonstrated that this effect, if combined with the influence of the atmosphere and oceans, improves substantially the agreement with celestial pole offsets observed by Very Long-Baseline Interferometry. Here we concentrate our efforts to study possible influence of GMJ on temporal changes of all five Earth orientation parameters defining the complete Earth orientation in space. Numerical integration of Brzeziński's broad-band Liouville equations (Brzeziński 1994) with atmospheric and oceanic excitations, combined with expected GMJ effects, is used to derive EOP and compare them with their observed values. We demonstrate that the agreement between all five Earth orientation parameters integrated by this method and those observed by space geodesy is improved substantially if the influence of additional excitations at GMJ epochs is added to excitations by the atmosphere and oceans.

  11. An Instrument Concept for Atmospheric Infrared Sounding from Medium Earth Orbit

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Baron, Richard l.

    2004-01-01

    Medium Earth Orbit (MEO) offers a unique vantage point for atmospheric infrared sounding. The orbit allows the entire globe to be covered each day with one satellite. The orbit is slow enough to allow multiple views of a single target to be made on each pass. this paper discusses the advantages in coverage and revisit rate from MEO for a particular concept for a Medium Earth Orbit Infrared Atmospheric Sounder (MIRIS). The requirements for this instrument in terms of spectral range, spatial resolution, field of view, and calibration are presented as well as the radiometric performance expectations.

  12. Effects of Large Solar Events on Atmospheric Drag of Earth Artificial Satellites

    NASA Astrophysics Data System (ADS)

    Mircea, Liviu

    2008-09-01

    Sharp bursts of Solar activity, in the form of highly energetic radiation (extreme UV and X-rays), mass transfers (coronal mass ejections) and energetic charged particles (electrons, protons and ions), act on the upper atmosphere of the Earth, and change its state parameters (temperature, structure-altitude distribution, chemical composition and density) and also interact with Earth's magnetic field. This solar outputs increase dramatically during cyclic periods of intensive solar activity or due to irregular major storm events. This are causing high temporary correlation with above mentioned state parameters perturbations, inducing thermospheric expansion and density increasing, generating atmospheric brake off terrestrial artificial satellites.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  14. Atmospheric excitation of the earth's annual wobble - 1980-1988

    NASA Technical Reports Server (NTRS)

    Chao, B. Fong; Au, Andrew Y.

    1991-01-01

    Global meteorological analyses from the European Center for Medium Range Weather Forecasts are employed to compute the atmospheric excitation psi of the polar motion for the 9-year period of 1980-1988. Both the matter component psi(matter) and the motion component psi (motion) are computed, the former with and without the oceanic inverted barometer (IB) effect. It is found that psi(motion) contributes significantly to the total excitation psi overall and nonnegligibly to the annual signal in psi, or the annual wobble excitation in particular. The results for the annual wobble excitation, in terms of the prograde component psi(t) and the retrogade component phsi(-) for January 1, are within the (rather large) range of previous estimates. The IB effect has a small impact on psi(+), whereas its impact on psi(-) is considerable.

  15. Heating and thermal transformation of micrometeoroids entering the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Love, S. G.; Brownlee, D. E.

    1991-01-01

    The present numerical solutions for the atmospheric entry of 10 micron-1 mm diameter micrometeoroids gave attention to ablative mass loss and cooling, together with gravitational and curvature effects, for entry velocities in the 11.2-72 km/sec range. Maximum temperature and mass-loss rates are found to generally occur at altitudes between 85 and 90 km, during about 1 sec of peak heating; the survival of all particles in the 70 micron-1 mm size range is noted to be limited to those with minimal entry velocity. Virtually all of the 'cosmic spherules' of more than 70-mm diameter, as well as giant unmelted micrometeorites, are implied by the present results to be of asteroidal origin.

  16. Climatic effects due to halogenated compounds in the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Wang, W.-C.; Pinto, J. P.; Yung, Y. L.

    1980-01-01

    Using a one-dimensional radiative-convective model, a sensitivity study is performed of the effect of ozone depletion in the stratosphere on the surface temperature. There could be a cooling of the surface temperature by approximately 0.2 K due to chlorofluoromethane-induced ozone depletion at steady state (assuming 1973 release rates). This cooling reduces significantly the greenhouse effect due to the presence of chlorofluoromethanes. Carbon tetrafluoride has a strong nu sub 3 band at 7.8 microns, and the atmospheric greenhouse effect is shown to be 0.07 and 0.12 K/ppbv with and without taking into account overlap with CH4 and N2O bands. At concentrations higher than 1 ppbv, absorption by the nu sub 3 band starts to saturate and the greenhouse effect becomes less efficient.

  17. Comparing the Atmospheres of Mercury and the Earth's Moon

    NASA Technical Reports Server (NTRS)

    Morgan, Thomas H.; Killen, Rosemary M.; Hurley, Dana M.

    2012-01-01

    The exospheres of Mercury and the Earth's Moon are fundamentally similar, but the differences that do exist between them can help us to develop a better understanding of the processes at work on the two bodies that produce and remove volatiles. The major differences are derived from (1) the different compositions of the two surfaces, (2) the different particle and field em'ironments above the surface of each body (particularly the presence of intrinsic magnetic field of Mercury), and (3) the larger flux of interplanetary dust incident at the orbit of Mercury. The first difference, surface composition, is the most intractable problem, but the most challenging part of that problem, the composition of the Hermean regolith, may be at least partially addressed as the MESSENGER mission completes work over the next year. Much progress has been made with respect to exploring the second difference above--spacecraft such as Helios, Ulysses, WIND, and ACE have measured the solar wind and its composition both in Earth orbit and at distances encompassing the orbit of Mercury. While our knowledge of the solar wind is incomplete, again it is far more detailed than a simple 1/R(sup 2) law would predict. Another problem is that of the flux of charged particles to the surfaces. While Mercury's magnetosphere is the subject of current study with MESSENGER, the influx of charged particles on the Moon has gone beyond a cos (psi) picture, where psi is the solar zenith angle. We know that the influx of ions at the Moon is affected by magnetic anomalies, by craters, and by surface charging. The third external difference is the differing flux of interplanetary dust incident on the two surfaces. In this talk we will consider: (1) the species that one can compare now for these two exospheres (Na, K, and He); (2) the species that you might be able to compare with future measurements (Ca and Mg); arid (3) how intensive ground-based observations of the easiest lunar species to observe from the

  18. Combined 2-micron Dial and Doppler Lidar: Application to the Atmosphere of Earth or Mars

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Koch, Grady J.; Ismail, Syed; Kavaya, Michael; Yu, Jirong; Wood, Sidney A.; Emmitt, G. David

    2006-01-01

    A concept is explored for combining the Doppler and DIAL techniques into a single, multifunctional instrument. Wind, CO2 concentration, and aerosol density can all be measured. Technology to build this instrument is described, including the demonstration of a prototype lidar. Applications are described for use in the Earth science. The atmosphere of Mars can also be studied, and results from a recently-developed simulation model of performance in the Martian atmosphere are presented.

  19. 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.

  20. Atmospheric correction of ocean-color sensors: effects of the Earth's curvature.

    PubMed

    Ding, K; Gordon, H R

    1994-10-20

    We investigate the influence of the curvature of the Earth on a proposed atmospheric-correction scheme for the Sea-Viewing Wide-Field-of-View Sensor (SeaWiFS) by simulating the radiance exiting the top of a spherical-shell atmosphere and inserting the result into the proposed correction algorithm. The error in the derived water-leaving reflectance suggests that the effects of the curvature are negligible for solar zenith angles (θ(0)) ≤ 70°. Furthermore, for θ(0) > 70° the error in atmospheric correction can usually be reduced if the molecular-scattering component of the top of the atmosphere reflectance (ρ(r)) is computed with a spherical-shell atmosphere radiative transfer code. Also, for θ(0) > 70° the error in atmospheric correction in a spherical-shell atmosphere, when ρ(r) is computed with a spherical-shell model, can be predicted reasonably well from computations made with plane-parallel atmosphere radiative transfer codes. This implies that studies aimed at improving atmospheric correction can be made assuming plane-parallel geometry and that the investigator can be confident when θ(0)> 70° that any improvements will still be valid for a spherical-shell atmosphere as long as ρ(r) is computed in spherical-shell geometry. Finally, a scheme for computing ρ(r) in a spherical-shell atmosphere in a relatively simple manner is developed. PMID:20941262

  1. Atmospheric Ar and Ne returned from mantle depths to the Earth's surface by forearc recycling.

    PubMed

    Baldwin, Suzanne L; Das, J P

    2015-11-17

    In subduction zones, sediments, hydrothermally altered lithosphere, fluids, and atmospheric gases are transported into the mantle, where ultrahigh-pressure (UHP) metamorphism takes place. However, the extent to which atmospheric noble gases are trapped in minerals crystallized during UHP metamorphism is unknown. We measured Ar and Ne trapped in phengite and omphacite from the youngest known UHP terrane on Earth to determine the composition of Ar and Ne returned from mantle depths to the surface by forearc recycling. An (40)Ar/(39)Ar age [7.93 ± 0.10 My (1σ)] for phengite is interpreted as the timing of crystallization at mantle depths and indicates that (40)Ar/(39)Ar phengite ages reliably record the timing of UHP metamorphism. Both phengite and omphacite yielded atmospheric (38)Ar/(36)Ar and (20)Ne/(22)Ne. Our study provides the first documentation, to our knowledge, of entrapment of atmospheric Ar and Ne in phengite and omphacite. Results indicate that a subduction barrier for atmospheric-derived noble gases does not exist at mantle depths associated with UHP metamorphism. We show that the crystallization age together with the isotopic composition of nonradiogenic noble gases trapped in minerals formed during subsolidus crystallization at mantle depths can be used to unambiguously assess forearc recycling of atmospheric noble gases. The flux of atmospheric noble gas entering the deep Earth through subduction and returning to the surface cannot be fully realized until the abundances of atmospheric noble gases trapped in exhumed UHP rocks are known. PMID:26542683

  2. Monitoring the Earth's Atmosphere with the Global IMS Infrasound Network

    NASA Astrophysics Data System (ADS)

    Brachet, Nicolas; Brown, David; Mialle, Pierrick; Le Bras, Ronan; Coyne, John; Given, Jeffrey

    2010-05-01

    The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is tasked with monitoring compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT) which bans nuclear weapon explosions underground, in the oceans, and in the atmosphere. The verification regime includes a globally distributed network of seismic, hydroacoustic, infrasound and radionuclide stations which collect and transmit data to the International Data Centre (IDC) in Vienna, Austria shortly after the data are recorded at each station. The infrasound network defined in the Protocol of the CTBT comprises 60 infrasound array stations. Each array is built according to the same technical specifications, it is typically composed of 4 to 9 sensors, with 1 to 3 km aperture geometry. At the end of 2000 only one infrasound station was transmitting data to the IDC. Since then, 41 additional stations have been installed and 70% of the infrasound network is currently certified and contributing data to the IDC. This constitutes the first global infrasound network ever built with such a large and uniform distribution of stations. Infrasound data at the IDC are processed at the station level using the Progressive Multi-Channel Correlation (PMCC) method for the detection and measurement of infrasound signals. The algorithm calculates the signal correlation between sensors at an infrasound array. If the signal is sufficiently correlated and consistent over an extended period of time and frequency range a detection is created. Groups of detections are then categorized according to their propagation and waveform features, and a phase name is assigned for infrasound, seismic or noise detections. The categorization complements the PMCC algorithm to avoid overwhelming the IDC automatic association algorithm with false alarm infrasound events. Currently, 80 to 90% of the detections are identified as noise by the system. Although the noise detections are not used to build events in the context of CTBT monitoring

  3. Characterizing the Atmosphere of Benchmark Super-Earth HD 97658b

    NASA Astrophysics Data System (ADS)

    Knutson, Heather

    2012-10-01

    Super-Earth planets are ubiquitous, diverse, and poorly characterized. Kepler has discovered several thousand planet candidates with radii intermediate between the Earth and Neptune, yet to date only one nearby super-Earth, GJ 1214b, has been studied in detail. We propose to measure the atmospheric scale height of HD 97658b, a recently detected close analogue of GJ 1214b in bulk mass and radius. HD 97658b is the only other super-Earth aside from GJ 1214b that can be easily characterized with HST, and is likely to be the target of multiple observing proposals in Cycle 22. By investing a small amount of telescope time now, we can ensure that the proposing teams and the HST TAC are able to make informed decisions about how best to use scarce observing resources. Our WFC3 measurement will cleanly distinguish a large scale-height, hydrogen-dominated atmosphere from a compact, water steam atmosphere. The measurement will also be the first and most important step toward characterizing the planet's bulk composition. Currently, the mass and radius measurements of HD 97658 are compatible with widely divergent interior compositions: a water world of half rock and half water, a mini-Neptune, or a planet of terrestrial composition with outgassed hydrogen. The detection of a low scale-height water atmosphere would strongly suggest a water world bulk composition, and a birth near or beyond the ice line of the protoplanetary disk. We will directly compare the atmospheres of HD 97658b and GJ 1214b, providing the first measure of the diversity of super-Earth atmospheres prior to the era of JWST.

  4. Super-Earth Atmospheres: Self-consistent Gas Accretion and Retention

    NASA Astrophysics Data System (ADS)

    Ginzburg, Sivan; Schlichting, Hilke E.; Sari, Re’em

    2016-07-01

    Some recently discovered short-period Earth- to Neptune-sized exoplanets (super-Earths) have low observed mean densities that can only be explained by voluminous gaseous atmospheres. Here, we study the conditions allowing the accretion and retention of such atmospheres. We self-consistently couple the nebular gas accretion onto rocky cores and the subsequent evolution of gas envelopes following the dispersal of the protoplanetary disk. Specifically, we address mass-loss due to both photo-evaporation and cooling of the planet. We find that planets shed their outer layers (dozens of percent in mass) following the disk's dispersal (even without photo-evaporation), and their atmospheres shrink in a few Myr to a thickness comparable to the radius of the underlying rocky core. At this stage, atmospheres containing less particles than the core (equivalently, lighter than a few percent of the planet's mass) can be blown away by heat coming from the cooling core, while heavier atmospheres cool and contract on a timescale of Gyr at most. By relating the mass-loss timescale to the accretion time, we analytically identify a Goldilocks region in the mass-temperature plane in which low-density super-Earths can be found: planets have to be massive and cold enough to accrete and retain their atmospheres, but not too massive or cold, such that they do not enter runaway accretion and become gas giants (Jupiters). We compare our results to the observed super-Earth population and find that low-density planets are indeed concentrated in the theoretically allowed region. Our analytical and intuitive model can be used to investigate possible super-Earth formation scenarios.

  5. Application of the DSMC Method in Modeling Earth's Rarefied Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Hoey, W.; Walker, A. C.; Goldstein, D. B.; Varghese, P. L.; Trafton, L. M.

    2014-12-01

    Improving the accuracy and robustness of simulations of Earth's upper atmosphere is a priority for satellite drag and space weather applications. The Direct Simulation Monte Carlo [DSMC] method is well-suited to modeling the dynamics of such rarefied and non-equilibrium regimes, where continuum techniques break down. Here, we apply DSMC in three-dimensional, transient, and self-consistent neutral density simulations of Earth's rarefied upper atmosphere.An existing planetary-science code base, established in the modeling of the lunar and Ionian environs, is extended to reflect the physics of Earth's upper atmosphere. Comprehensive atmospheric simulations are computed in parallel on a domain extending from the mid-thermosphere, below the continuum-rarefied transition, through 1000 km altitude. The simulation code includes multi-species neutral- and photo-chemistry, tracking of particle rotational and vibrational states, and non-equilibrium radiation transport. Substantial model development is demonstrated in application to the Earth's atmosphere, including the incorporation of lower-boundary conditions consistent with the NRLMSISE-00 semi-empirical model, ultraviolet radiation and photo-chemistry rates modeled with reference to space weather indices, and radiative absorption attenuated by integrated column density.Comparisons with results drawn from existing upper atmospheric models and from indirect satellite mass density measurements are employed in benchmarking model accuracy. Avenues for further development include hybridization with continuum global circulation models in the mid-thermosphere, and the extension of the planetary code's magnetic field and charged-particle models to the Earth case.Research supported by the Los Alamos Space Weather Summer School, LANL Institutional Computing, and the Institute of Geophysics, Planetary Physics, and Signatures (IGPPS) at LANL.

  6. The State of the Earth's Atmosphere 3.5 Ga Ago

    NASA Astrophysics Data System (ADS)

    Marty, B.; Avice, G.; Kuga, M.

    2014-12-01

    The atmosphere evolved through time upon escape to space and exchange of volatile elements with the Earth's solid reservoirs (mantle, crust). We are currently investigating the composition of the ancient atmosphere by analyzing gases trapped in Archean chemical sedimentary rocks, including fluid inclusions in Archean hydrothermal quartz. The rationale of the study is that trapped noble gases, as well as nitrogen for some of the samples, represent ancient atmospheric gases that were dissolved in surface fluids (seawater, freshwater), so that their isotope compositions and elemental ratios reflect those of the Archean atmosphere at the time of trapping. Particular care was given to select samples for which fluids did not exchange significantly since the epoch of trapping. Data show that: (i) the felsic continental crust grew up mostly during the time interval 3.5-2.7 Ga ago [1]; (ii) the atmospheric nitrogen isotope composition and density were comparable to the modern one, implying the existence of a significant terrestrial magnetic field at that time [2]; (iii) Archean neon and krypton isotopic ratios were similar to their modern ones; but (iv) the xenon isotopic composition was isotopically fractionated and intermediate between those of potential cosmochemical (chondritic, solar) end-members and of the present-day atmosphere[3,4]. These differences are attributed to different ionization efficiencies for atmospheric species, and subsequent escape to space for Xe [3-5]. Together with the constant Ne, Kr and N isotope compositions, they shed strong constraints on the nature of the solar UV flux 1Ga after Earth's formation. [1] Pujol. M. et al. (2013), Nature 498, 87-90. [2] Marty B. et al. (2013), Science 342, 101-104. [3] Pujol M. et al. (2011), Earth Planet. Sci. Lett., 308, 298-306. [4] Avice G. & Marty B. Phil. Trans. R. Soc. A, In press. [5] Hébrard E. & Marty B. (2014), Earth Planet. Sci. Lett., 385, 40-48.

  7. Heterogeneous Chemical Transformation of Incident Exogenous Organic Material in Earth's Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Belle, C. L.; Kress, M. E.; Iraci, L. T.

    2009-12-01

    On average, 10^8 g of solar system debris impinges on the Earth system each day. It is estimated that a few percent of this material is carbonaceous in nature, yet the fate of this organic material once it enters our atmosphere is unexplored. Much of this incoming material arrives in the form of micrometeoroids which are large enough to suffer drag heating and volatilize their organic material. Preliminary work shows that the organic material contained in particles with diameters on the order of 10-100 um is expected to be volatilized at altitudes of 100-120 km. Observed species include aromatic compounds such as alkybenzenes, phenol, benzonitrile, naphthalene, and styrene. Once liberated, these molecules may be transformed by processes at the boundary of space, or may survive to be mixed throughout the atmosphere. Sulfuric acid particles exist in Earth's upper atmosphere, and organic compounds often react strongly with this acid. We will report the results of laboratory and theoretical investigations of the interaction of aromatic compounds with surrogate matrices which mimic upper atmospheric particles. These studies will explore how exogenous organic compounds are altered after liberation at altitudes near 100 km and will determine if they survive to reach the surface of the Earth, where they may have provided the starting materials for the evolution of life on Earth or on other bodies.

  8. Comparing Unique Title Coverage of Web of Science and Scopus in Earth and Atmospheric Sciences

    ERIC Educational Resources Information Center

    Barnett, Philip; Lascar, Claudia

    2012-01-01

    The current journal titles in earth and atmospheric sciences, that are unique to each of two databases, Web of Science and Scopus, were identified using different methods. Comparing by subject category shows that Scopus has hundreds of unique titles, and Web of Science just 16. The titles unique to each database have low SCImago Journal Rank…

  9. Effects of atmospheric aerosols on scattering reflected visible light from earth resource features

    NASA Technical Reports Server (NTRS)

    Noll, K. E.; Tschantz, B. A.; Davis, W. T.

    1972-01-01

    The vertical variations in atmospheric light attenuation under ambient conditions were identified, and a method through which aerial photographs of earth features might be corrected to yield quantitative information about the actual features was provided. A theoretical equation was developed based on the Bouguer-Lambert extinction law and basic photographic theory.

  10. Introduction to simulation of upper atmosphere oxygen satellite exposed to atomic oxygen in low Earth orbit

    NASA Technical Reports Server (NTRS)

    Peplinski, D. R.; Arnold, G. S.; Borson, E. N.

    1984-01-01

    A brief review of atmospheric composition in low Earth orbit is presented. The flux of ambient atomic oxygen incident on a surface orbiting in this environment is described. Estimates are presented of the fluence of atomic oxygen to which satellite surfaces in various orbits are exposed.

  11. A Special Assignment from NASA: Understanding Earth's Atmosphere through the Integration of Science and Mathematics

    ERIC Educational Resources Information Center

    Fox, Justine E.; Glen, Nicole J.

    2012-01-01

    Have your students ever wondered what NASA scientists do? Have they asked you what their science and mathematics lessons have to do with the real world? This unit about Earth's atmosphere can help to answer both of those questions. The unit described here showcases "content specific integration" of science and mathematics in that the lessons meet…

  12. Runaway and moist greenhouse atmospheres and the evolution of Earth and Venus.

    PubMed

    Kasting, J F

    1988-01-01

    A one-dimensional climate model is used to study the response of an Earth-like atmosphere to large increases in solar flux. For fully saturated, cloud-free conditions, the critical solar flux at which a runaway greenhouse occurs, that is, the oceans evaporate entirely, is found to be 1.4 times the present flux at Earth's orbit (S0). This value is close to the flux expected at Venus' orbit early in solar system history. Is is nearly independent of the amount of CO2 present in the atmosphere, but is sensitive to the H2O absorption coefficient in the 8- to 12-micrometers window region. Clouds should tend to depress the surface temperature on a warm, moist planet; thus, Venus may originally have had oceans if its initial water endowment was close to that of Earth. It lost them early in its history, however, because of rapid photodissociation of water vapor followed by escape of hydrogen to space. The critical solar flux above which water is rapidly lost could be as low as 1.1S0. The surface temperature of a runaway greenhouse atmosphere containing a full ocean's worth of water would have been in excess of 1500 degrees K--above the solidus for silicate rocks. The presence of such a steam atmosphere during accretion may have significantly influenced the early thermal evolution of both Earth and Venus. PMID:11538226

  13. The composition of the primitive atmosphere and the synthesis of organic compounds on the early Earth

    NASA Technical Reports Server (NTRS)

    Bada, J. L.; Miller, S. L.

    1985-01-01

    The generally accepted theory for the origin of life on the Earth requires that a large variety of organic compounds be present to form the first living organisms and to provide the energy sources for primitive life either directly or through various fermentation reactions. This can provide a strong constraint on discussions of the formation of the Earth and on the composition of the primitive atmosphere. In order for substantial amounts of organic compounds to have been present on the prebiological Earth, certain conditions must have existed. There is a large body of literature on the prebiotic synthesis of organic compounds in various postulated atmospheres. In this mixture of abiotically synthesized organic compounds, the amino acids are of special interest since they are utilized by modern organisms to synthesize structural materials and a large array of catalytic peptides.

  14. A Reducing Atmosphere From Out-gassing of the Early Earth

    NASA Astrophysics Data System (ADS)

    Schaefer, L.; Fegley, B., Jr.

    2005-08-01

    Earth's present atmosphere originated from out-gassing of volatile-bearing grains. We calculated the composition of volatiles out-gassed from chondritic planetary bodies. We present results for average CI, CM, CV, H, L, and EH chondrites, which are the building blocks of the Earth. From the oxygen-isotope mixing (OIM) model, we calculated a composition of 70% EH, 21% H, 5% CV, and 4% CI chondritic matter for the early Earth. The major out-gassed volatiles for these starting compositions are CH4, N2, NH3, H2, and H2O. The Miller-Urey experiment demonstrated that a reducing atmosphere like this generates amino acids and other organic compounds that are essential for the formation of life. This work is supported by the NASA Astrobiology Program. \\leavevmode \\epsfxsize=0.9\\hsize \\epsfbox{49.eps}

  15. Potential biosignatures in super-Earth atmospheres. I. Spectral appearance of super-Earths around M dwarfs

    NASA Astrophysics Data System (ADS)

    Rauer, H.; Gebauer, S.; Paris, P. V.; Cabrera, J.; Godolt, M.; Grenfell, J. L.; Belu, A.; Selsis, F.; Hedelt, P.; Schreier, F.

    2011-05-01

    Atmospheric temperature and mixing ratio profiles of terrestrial planets vary with the spectral energy flux distribution for different types of M-dwarf stars and the planetary gravity. We investigate the resulting effects on the spectral appearance of molecular absorption bands, which are relevant as indicators for potential planetary habitability during primary and secondary eclipse for transiting terrestrial planets with Earth-like biomass emissions. Atmospheric profiles are computed using a plane-parallel, 1D climate model coupled with a chemistry model. We then calculate simulated spectra using a line-by-line radiative transfer model. We find that emission spectra during secondary eclipse show increasing absorption of methane, water, and ozone for planets orbiting quiet M0-M3 dwarfs and the active M-type star AD Leo compared with solar-type central stars. However, for planets orbiting very cool and quiet M dwarfs (M4 to M7), increasing temperatures in the mid-atmosphere lead to reduced absorption signals, which impedes the detection of molecules in these scenarios. Transmission spectra during primary eclipse show strong absorption features of CH4, N2O and H2O for planets orbiting quiet M0-M7 stars and AD Leo. The N2O absorption of an Earth-sized planet orbiting a quiet M7 star can even be as strong as the CO2 signal. However, ozone absorption decreases for planets orbiting these cool central stars owing to chemical effects in the atmosphere. To investigate the effect on the spectroscopic detection of absorption bands with potential future satellite missions, we compute signal-to-noise-ratios (SNR) for a James Webb Space Telescope (JWST)-like aperture telescope.

  16. Earth history. Low mid-Proterozoic atmospheric oxygen levels and the delayed rise of animals.

    PubMed

    Planavsky, Noah J; Reinhard, Christopher T; Wang, Xiangli; Thomson, Danielle; McGoldrick, Peter; Rainbird, Robert H; Johnson, Thomas; Fischer, Woodward W; Lyons, Timothy W

    2014-10-31

    The oxygenation of Earth's surface fundamentally altered global biogeochemical cycles and ultimately paved the way for the rise of metazoans at the end of the Proterozoic. However, current estimates for atmospheric oxygen (O2) levels during the billion years leading up to this time vary widely. On the basis of chromium (Cr) isotope data from a suite of Proterozoic sediments from China, Australia, and North America, interpreted in the context of data from similar depositional environments from Phanerozoic time, we find evidence for inhibited oxidation of Cr at Earth's surface in the mid-Proterozoic (1.8 to 0.8 billion years ago). These data suggest that atmospheric O2 levels were at most 0.1% of present atmospheric levels. Direct evidence for such low O2 concentrations in the Proterozoic helps explain the late emergence and diversification of metazoans. PMID:25359975

  17. Differential radiometry for measuring the net radiative flux in the earth`s atmosphere

    SciTech Connect

    La Delfe, P.C.; Love, S.P.; Weber, P.G.

    1996-11-01

    The Hemispheric Optimized NEt Radiometer (HONER) is very briefly described. HONER was developed to resolve technical issues impeding the accurate measurement of atmospheric radiative flux. HONER uses differential radiometry, chopping the signal from upwelling and downwelling fluxes onto a single AC detector system, allowing true optical differencing as well as measurements of the individual fluxes. Wavelength coverage encompasses ultraviolet to more than 50 micrometers. HONER has been used in a ground-based version and will be tested on the Perseus B Unmanned Aerospace Vehicle.

  18. A new way to Estimate the Earth's Radiation Budget at the top-of-atmosphere

    NASA Astrophysics Data System (ADS)

    Zhu, Ping; Karatekin, Ozgur; van Ruymbeke, Michel; Dewitte, Steven; Meftah, Mustapha

    2014-05-01

    The Earth's Radiation Budget at the top-of-atmosphere (TOA) is investigated by combining remote sensing data from different Earth observing satellites and the solar radiation monitoring from dedicated missions. Despite the relatively high precision of each individual instruments, the uncertainties in the current net radiation derived at the TOA is still too large to track small energy imbalance associated with forced climate change. A new method to estimate the net energy balance at the TOA is introduced based on nearly three years space experiments from the Bolometric Oscillation Sensor (BOS) onboard PICARD satellite. PICARD satellite is circling the Earth on a heliocentric orbit, the descending and the ascending nodes of the PICARD are around 6 a.m. and 6 p.m. local time, respectively. The BOS sensor onboard PICARD satellite is sensitive to the radiation coming from both the sun and the Earth. Besides solar shortwave electromagnetic radiation, the black-coated BOS sensor measures also the reflected (visible) and reemitted (infrared) terrestrial radiation. The net radiation of the Earth is described as: fnet = fin - (fvis +fir) (1) Where fnet, the net radiation of the Earth at the TOA, fin, the incoming solar irradiance, fvis, the reflected solar radiation at the TOA, fir infrared radiation of the Earth. The energy absorbed by the main detector of the BOS can be approximately written as: fbos = fsun + (fvis + fir) (2) Where fbos, the measurements of the BOS instruments, fvis, the reflected solar radiation at the TOA, fir infrared radiation of the Earth. Frome equation (1) and (2), we can found a new method to estimate the net radiation: fnet = fsun +fin - fbos (3) BOS/PICARD experiment allows us to employ this new approach to study the Earth's Radiation Budget from a single remote sensing instrument. Here we discuss the BOS data between July 2010 and October 2013 and their implication on Earth's Radiation Budget estimate.

  19. Application of Spaceborne Infrared Atmospheric Sounder for Geosynchronous Earth Orbit (SIRAS-G) technology to future Earth science missions

    NASA Astrophysics Data System (ADS)

    Kampe, Thomas U.

    2008-04-01

    The Spaceborne Infrared Sounder for Geosynchronous Earth Orbit (SIRAS-G) was developed by Ball Aerospace & Technologies Corp (BATC) under NASA's 2002 Instrument Incubator Program. SIRAS-G was a technology development program focused on next-generation IR imaging spectrometers for sounding of the atmosphere. SIRAS-G demonstrated that the dispersive grating spectrometer is a suitable instrument architecture for this application. In addition to providing atmospheric temperature and water vapor profiles, SIRAS-G can provide trace gases concentrations, land and ocean surface temperatures and the IR mineral dust aerosol signature from satellite. The 3-year SIRAS-G IIP development effort included the successful cryogenic testing of the SIRAS-G laboratory demonstration spectrometer operating in the 2083 to 2994 cm -1 frequency range. The performance of the demonstration instrument has been quantified including measurement of keystone distortion, spectral smile, MTF, and the spectral response function (SRF). Development efforts associated with this advanced infrared spectrometer technology provides the basis for instrumentation to support future Earth science missions.

  20. Contributions of high-altitude winds and atmospheric moment of inertia to the atmospheric angular momentum-earth rotation relationship

    NASA Technical Reports Server (NTRS)

    Taylor, H. A., Jr.; Mayr, H. G.; Kramer, L.

    1985-01-01

    For many years it has been recognized that recurrent modulations occur in the time series of the earth's rotation rate or, alternatively, the change in the length of the day (Delta-LOD). Studies relating Delta-LOD to global patterns of zonal winds have confirmed that the variability of atmospheric angular momentum (M) is of sufficient magnitude to account for a large portion of the gross periodicities observed in the earth rotation. The present investigation is concerned with the importance of the contributions of the moment of inertia and high-altitude winds to the angular momentum budget. On the basis of an analysis of the various factors, it is found that within the available data, contributions of high-altitude winds and atmospheric moment of inertia reach levels detectable in the atmospheric angular momentum budget. Nevertheless, for the period December 1978 to December 1979 these contributions are not sufficient to resolve the apparent short-term discrepancies which are evident between Delta-LOD and M.

  1. Photochemical consequences of enhanced CO2 levels in earth's early atmosphere

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.

    1985-01-01

    Greatly enhanced atmospheric CO2 concentrations are the most likely mechanism for offsetting the effects of reduced solar luminosity early in the earth's history. CO2 levels of 80 to 600 times the present value could have maintained a mean surface temperature of 0 C to 15 C, given a 25 percent decrease in solar output. Such high CO2 levels are at least qualitatively consistent with the present understanding of the carbonate-silicate geochemical cycle. The presence of large amounts of CO2 has important implications for the composition of the earth's prebiotic atmosphere. The hydrogen budget of a high-CO2 primitive atmosphere would have been strongly influenced by rainout of H2O2 and H2CO. The reaction of H2O2 with dissolved ferrous iron in the early oceans could have been a major sink for atmospheric oxygen. The requirement that this loss of oxygen be balanced by a corresponding loss of hydrogen (by escape to space and rainout of H2CO) implies that the atmospheric H2 mixing ratio was greater than 2 x 10 to the -5th and the ground level O2 mixing ratio was below 10 to the -12th, even if other surface sources of H2 were small. These results are only weakly dependent on changes in solar UV flux, rainout rates, and vertical mixing rates in the primitive atmosphere.

  2. The Impact of Solar Activity on the Earth Upper Atmosphere as Inferred from the CORONAS-F Scientific Experiments

    NASA Astrophysics Data System (ADS)

    Boldyrev, S. I.; Egorov, I. A.; Zhitnik, I. A.; Ivanov-Kholodny, G. S.; Ignat'yev, S. P.; Ishkov, V. N.; Kolomiitsev, O. P.; Kuzin, S. V.; Kuznetsov, V. D.; Osin, A. I.

    The chapter is devoted to the first results of processing and analysis of data on the absorption of solar XUV radiation in the Earth upper atmosphere measured onboard the CORONAS-F space mission. The variability of the Earth's upper atmosphere associated with solar activity has been studied by analyzing the orbital evolution of the CORONAS-F satellite. Experimental data have been compared with model calculations of the parameters of the upper atmosphere. The mathematical model of the Earth upper atmosphere (WMA01) developed at IZMIRAN is described in general terms. A list of active events on the Sun and associated processes in the Earth magnetosphere recorded during the CORONAS-F flight time (2001-2005) is presented. The comparison of model calculations with the experimental satellite data shows that the Earth atmosphere models available need updating. The possible ways to attack this problem are discussed.

  3. Global Reference Atmospheric Models, Including Thermospheres, for Mars, Venus and Earth

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, C. G.; Keller, Vernon W.

    2006-01-01

    This document is the viewgraph slides of the presentation. Marshall Space Flight Center's Natural Environments Branch has developed Global Reference Atmospheric Models (GRAMs) for Mars, Venus, Earth, and other solar system destinations. Mars-GRAM has been widely used for engineering applications including systems design, performance analysis, and operations planning for aerobraking, entry descent and landing, and aerocapture. Preliminary results are presented, comparing Mars-GRAM with measurements from Mars Reconnaissance Orbiter (MRO) during its aerobraking in Mars thermosphere. Venus-GRAM is based on the Committee on Space Research (COSPAR) Venus International Reference Atmosphere (VIRA), and is suitable for similar engineering applications in the thermosphere or other altitude regions of the atmosphere of Venus. Until recently, the thermosphere in Earth-GRAM has been represented by the Marshall Engineering Thermosphere (MET) model. Earth-GRAM has recently been revised. In addition to including an updated version of MET, it now includes an option to use the Naval Research Laboratory Mass Spectrometer Incoherent Scatter Radar Extended Model (NRLMSISE-00) as an alternate thermospheric model. Some characteristics and results from Venus-GRAM and Earth-GRAM thermospheres are also presented.

  4. L2 Earth Atmosphere Observatory: Formation Guidance, Metrology and Control Synthesis

    NASA Technical Reports Server (NTRS)

    Acikmese, Ahmet Behcet; Mettler, Edward; Breckenridge, William G.; Macenka, Steven A.; Tubbs, Eldred F.

    2004-01-01

    The Earth Observatory Formation at L2, a Lagrange libration point, is a unique large aperture (25 m diameter) space telescope concept that will improve the knowledge and understanding of dynamic, chemical and radiative mechanisms that cause changes in the atmosphere, and can lead to the development of models and techniques to predict short and long-term climate changes. The results of this concept definition study show that the telescope concept is feasible, and can have technology readiness in the 2020 time frame. Further advanced development in several subsystems is needed, such as higher efficiency Xenon ion thrusters with throttling, and optical quality large membrane mirror with active shape control. It presents an analysis and solution of guidance, sensing, control, and propulsion problems for a formation of two spacecraft on the Sun-Earth line in the neighborhood of the Sun-Earth L2 point, that observes Earth s atmosphere during continuous solar occultation by the Earth. A system architecture is described for the observatory, and its components that include unique mission specific metrology. The formation must follow a powered trajectory with strictly limited fuel use to observe solar occultation. A configuration of ion thrusters and reaction wheels for translation and attitude control is designed along with algorithms for orbit following and formation control. Simulation results of the orbital and formation dynamics are presented that verify performance of the control systems.

  5. Solution of Time-dependent Hydrodynamic Equations and application in Early Earth's Atmosphere

    NASA Astrophysics Data System (ADS)

    Tian, F.; Toon, O. B.; Pavlov, A. A.; Sterck, H. D.

    2003-12-01

    Hydrodynamic escape has important applications in the formation and evolution of planetary atmospheres. Watson et. al. (1981) treated the time-independent hydrodynamic equations by assuming single layer heating and this approach has been followed by researches in this field since then. Solutions to the time-independent hydrodynamic equations are difficult to find due to the existence of a singularity point. In our work, the Lax-Friedrichs scheme is used to solve the 1D time-dependent hydrodynamic equations without the single layer heating approximation. Our results show that variables such as energy input rate at the top of the atmosphere, density and temperature at the homopause have a non-linear impact on the escape flux. In our preliminary calculations, for the same hydrogen mixing ratio near homopause in Earth's atmosphere, hydrodynamic escape flux driven by intense solar EUV heating is much smaller than the diffusion limited escape flux. This escape rate suggests that the huge amount of H2 outgassing from interior of the Earth to compensate the previously assumed large scale escape may not be necessary to support substantial CH4 mixing ratios in the early Earth's atmosphere. FT is supported by the CU Astrobiology Institute.

  6. Earth-Atmospheric Coupling During Strong Earthquakes by Analyzing MODIS Data

    NASA Technical Reports Server (NTRS)

    Ouzounov, Dimitar; Williams, Robin G.; Freund, Friedemann

    2001-01-01

    Interactions between the Earth and the atmosphere during major earthquakes (M greater than 5) are the subject of this investigation. Recently a mechanism has been proposed predicting the build-up of positive ground potentials prior to strong earthquake activity. Connected phenomena include: transient conductivity of rocks, injection of currents, possibly also electromagnetic emission and light emission from high points at the surface of the Earth. To understand this process we analyze vertical atmospheric profiles, land surface and brightness (temperature) data, using the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard NASA's Terra satellite launched in December 1999. MODIS covers the entire Earth every 1-2 days in 36 wavelength bands (20 visible and 16 infrared) at different spatial resolutions (250 m, 500 m, and 1 km). Using MODIS data we look for correlations between the atmospheric dynamics and solid Earth processes for the January 2001 strong earthquakes in San Salvador and India. As part of the build-up of positive grounds potential, an IR luminescence is predicted to occur in the 8-12 micrometer band. We use the MODIS data to differentiate between true "thermal" signals and IR luminescence. Indeed, on the basis of a temporal and spatial distribution analysis, a thermal anomaly pattern is found that appears to be related to the seismic activity. Aerosol content and atmospheric instability parameters also change when ground charges build up causing ion emission and leading to a thin aerosol layer over land. We analyze the aerosol content, atmospheric pressure, moisture profile and lifted index. Anomalous trends have been identified in few days prior to the main shocks. The significance of this observation should be explored further using other data sets.

  7. LASA (Lidar Atmospheric Sounder and Altimeter) Earth Observing System. Volume 2D: Instrument Panel Report

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The Earth Observing System (Eos) will provide an ideal forum in which the stronly synergistic characteristics of the lidar systems can be used in concert with the characteristics of a number of other sensors to better understand the Earth as a system. Progress in the development of more efficient and long-lasting laser systems will insure their availability in the Eos time frame. The necessary remote-sensing techniques are being developed to convert the Lidar Atmospheric Sounder and Altimeter (LASA) observations into the proper scientific parameters. Each of these activities reinforces the promise that LASA and GLRS will be a reality in the Eos era.

  8. Teaching about the Early Earth: Evolution of Tectonics, Life, and the Early Atmosphere

    NASA Astrophysics Data System (ADS)

    Mogk, D. W.; Manduca, C. A.; Kirk, K.; Williams, M. L.

    2007-12-01

    The early history of the Earth is the subject of some of the most exciting and innovative research in the geosciences, drawing evidence from virtually all fields of geoscience and using a variety of approaches that include field, analytical, experimental, and modeling studies. At the same time, the early Earth presents unique opportunities and challenges in geoscience education: how can we best teach "uncertain science" where the evidence is either incomplete or ambiguous? Teaching about early Earth provides a great opportunity to help students understand the nature of scientific evidence, testing, and understanding. To explore the intersection of research and teaching about this enigmatic period of Earth history, a national workshop was convened for experts in early Earth research and undergraduate geoscience education. The workshop was held in April, 2007 at the University of Massachusetts at Amherst as part of the On the Cutting Edge faculty professional development program. The workshop was organized around three scientific themes: evolution of global tectonics, life, and the early atmosphere. The "big scientific questions" at the forefront of current research about the early Earth were explored by keynote speakers and follow-up discussion groups: How did plate tectonics as we know it today evolve? Were there plates in the Hadean Eon? Was the early Earth molten? How rapidly did it cool? When and how did the atmosphere and hydrosphere evolve? How did life originate and evolve? How did all these components interact at the beginning of Earth's history and evolve toward the Earth system we know today? Similar "big questions" in geoscience education were addressed: how to best teach about "deep time;" how to help students make appropriate inferences when geologic evidence is incomplete; how to engage systems thinking and integrate multiple lines of evidence, across many scales of observation (temporal and spatial), and among many disciplines. Workshop participants

  9. Infrared limb-darkening effects for the earth-atmosphere system

    NASA Technical Reports Server (NTRS)

    Gupta, S. K.; Suttles, J. T.; Tiwari, S. N.; Vemuru, C. S.

    1983-01-01

    An infrared radiative transfer model has been developed for evaluating anisotropic functions in the longwave region (5-50 microns) due to limb-darkening effects in the earth's atmosphere. An accurate narrow-band model of absorption has been used for computing transmission functions of the atmosphere. Absorption due to all major and minor atmospheric constituents has been taken into account including the continuum absorption due to water vapor. Anisotropic functions have been calculated for several latitudinal and seasonal climatological-average model atmospheres. The effects of the variability of various meteorological parameters, e.g. surface temperature, surface relative humidity, and cloud-top height have been examined. It has been found that the variability of cloud parameters has the largest effect on the infrared anisotropic functions.

  10. Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets

    NASA Astrophysics Data System (ADS)

    Kasting, James F.; Chen, Howard; Kopparapu, Ravi K.

    2015-11-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3D calculations. However, at surface temperatures above 350 K, the stratosphere warms and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a moist greenhouse explanation for loss of water from Venus, or some exoplanet receiving a comparable amount of stellar radiation, remains a viable hypothesis. Temperatures in the upper parts of such atmospheres are well below those estimated for a gray atmosphere, and this factor should be taken into account when performing inverse climate calculations to determine habitable zone boundaries using 1D models.

  11. A parallel Atmosphere-Ocean Global Circulation Model of intermediate complexity for Earth system climate research

    NASA Astrophysics Data System (ADS)

    Silva, T. A.; Schmittner, A.

    2007-12-01

    We present the evolution of an Earth System model of intermediate complexity featuring an ocean global circulation model to include a fully coupled 3D primitive equations atmospheric model. The original Earth System climate model, UVic ESCM (Weaver et al. 2001), uses an ocean global circulation model coupled to a one layer atmospheric energy-moisture balance model. It also comprises a viscous-plastic rheology sea ice model, a mechanical land ice model, land surface, oceanic and terrestrial carbon models and a simple 3D marine ecosystem model (Schmittner et al. 2005). A spectral atmospheric, model, PUMA (Fraedrich et al. 2005), was coupled to the UVic ESCM to provide an atmosphere with nonlinear dynamics in target resolutions of T21, T31 and T42, as required. The coupling with the atmosphere, which involves data transfer, preprocessing and interpolation, is done through the OASIS3 coupler. During a run there are 2 + 2N parallel processes: the UVic ESCM, the Oasis3 coupler and the PUMA model with its domain split across 2N processes. The choice of N allows to balance more or less complex configurations of UVic model (e.g. higher level marine ecosystem model or number of biogeochemical tracers) with the atmospheric model at different resolutions, in order to maintain computational efficiency. The relatively simple parameterizations make this new atmosphere-ocean global circulation model much faster than a state-of-the-art Atmosphere-Ocean Global Circulation Model, and so optimally geared for decadal to millennial scale integrations. The latter require special care with the conservation of fluxes during coupling. A second order conservative interpolation method was applied (Jones 1999) and this is compared with the use of typical non-conservative methods.

  12. Study of the dynamics of meteoroids through the Earth's atmosphere and retrieval of meteorites

    NASA Astrophysics Data System (ADS)

    Guadalupe Cordero Tercero, Maria; Farah-Simon, Alejandro; Velázquez-Villegas, Fernando

    2016-07-01

    When a comet , asteroid or meteoroid impact with a planet several things can happen depending on the mass, velocity and composition of the impactor, if the planet or moon has an atmosphere or not, and the angle of impact. On bodies without an atmosphere like Mercury or the Moon, every object that strikes their surfaces produces impact craters with sizes ranging from centimeters to hundreds and even thousands of kilometers across. On bodies with an atmosphere, this encounter can produce impact craters, meteorites, meteors and fragmentation. Each and every one of these phenomena is interesting because they provide information about the surfaces and the geological evolution of solar system bodies. Meteors (shooting stars) are luminous wakes on the sky due to the interaction between the meteoroid and the Earth's atmosphere. A meteoroid is asteroidal or cometary material ranging in size from 2 mm to a few tens of meters. The smallest tend to evaporate at heights between 80 and 120 km. Objects of less than 2 mm are called micrometeorites. If the meteor brightness exceeds the brightness of Venus, the phenomenon is called a bolide or fireball. If a meteoroid, or a fragment of it, survives atmospheric ablation and it can be recovered on the ground, that piece is called a meteorite. Most meteoroids 2 meters long fragment suddenly into the atmosphere, it produces a shock wave that can affect humans and their environment like the Chelyabinsk event occurred on February 15, 2013 an two less energetic events in Mexico in 2010 and 2011. To understand the whole phenomenon, we proposed a video camera network for observing meteors. The objectives of this network are to: a) contribute to the study of the fragmentation of meteoroids in the Earth's atmosphere, b) determine values of important physical parameters; c ) study seismic waves produced by atmospheric shock waves, d) study the dynamics of meteoroids and f ) recover and study meteorites. During this meeting, the academic

  13. Loss of Water in Early Earth's Atmosphere and Its Effects on Habitability

    NASA Astrophysics Data System (ADS)

    Airapetian, Vladimir; Glocer, Alex; Khazanov, George

    2015-08-01

    The short wavelength emission from the Sun has a profound impact on the Earth’s atmosphere. High energy photons ionize the atmosphere and produce photoelectrons. This process provides a major contribution to the acceleration of atmospheric ions due to the vertical separation of ions and electrons, and the formation of the resulting ambipolar electric field. Observations and theory suggest that even a relatively small fraction of super-thermal electrons (photoelectrons) produced due to photoionization can drive the ”polar wind” that is responsible for the transport of ionospheric constituents to the Earth’s magnetosphere.The young Sun was a magnetically active star generating powerful radiative output from its chromosphere, transition region and corona which was a few hundred times greater than that observed today. What effects would the photoionization processes due to the X-ray-UV solar flux from early Sun have on the loss of water from the early Earth?We use the Fokker-Plank code coupled with 1D hydrodynamic code to model the effect of intensive short-wavelength (X-rays to UV band) emission from the young Sun (3.8 and 4.4 Ga) on Earth's atmosphere. Our simulations include the photoionization processes of the Earth’s atmosphere forming a population of photoelectrons (E<600 eV), the kinetic effects of their propagation associated and their contribution in ionosphere - magnetosphere energy redistribution. Our coupled simulations show that the ambipolar electric field can drag atmospheric ions of oxygen and hydrogen to the magnetosphere and produce significant mass loss that can affect the loss of water from the early Earth in the first half a billion years. This process became less efficient in the next 0.2-0.3 Ga that could have provided a window of opportunity for origin of life.

  14. Composition of the earth's atmosphere by shock-layer radiometry during the PAET entry probe experiment.

    NASA Technical Reports Server (NTRS)

    Whiting, E. E.; Arnold, J. O.; Page, W. A.; Reynolds, R. M.

    1973-01-01

    A determination of the composition of the earth's atmosphere obtained from onboard radiometer measurements of the spectra emitted from the bow shock layer of a high-speed entry probe is reported. The N2, O2, CO2, and noble gas concentrations in the earth's atmosphere were determined to good accuracy by this technique. The results demonstrate unequivocally the feasibility of determining the composition of an unknown planetary atmosphere by means of a multichannel radiometer viewing optical emission from the heated atmospheric gases in the region between the bow shock wave and the vehicle surface. The spectral locations in this experiment were preselected to enable the observation of CN violet, N2(+) first negative and atomic oxygen emission at 3870, 3910, and 7775 A, respectively. The atmospheric gases were heated and compressed by the shock wave to a peak temperature of about 6100 K and a corresponding pressure of 0.4 atm. Complete descriptions of the data analysis technique and the onboard radiometer and its calibration are given.

  15. Possible cometary origin of heavy noble gases in the atmospheres of Venus, Earth and Mars

    PubMed

    Owen, T; Bar-Nun, A; Kleinfeld, I

    1992-07-01

    Models that trace the origin of noble gases in the atmospheres of the terrestrial planets (Venus, Earth and Mars) to the 'planetary component' in chondritic meteorites confront several problems. The 'missing' xenon in the atmospheres of Mars and Earth is one of the most obvious; this gas is not hidden or trapped in surface materials. On Venus, the absolute abundances of neon and argon per gram of rock are higher even than those in carbonaceous chondrites, whereas the relative abundances of argon and krypton are closer to solar than to chondritic values (there is only an upper limit on xenon). Pepin has developed a model that emphasizes hydrodynamic escape of early, massive hydrogen atmospheres to explain the abundances and isotope ratios of noble gases on all three planets. We have previously suggested that the unusual abundances of heavy noble gases on Venus might be explained by the impact of a low-temperature comet. Further consideration of the probable history of the martian atmosphere, the noble-gas data from the (Mars-derived) SNC meteorites and laboratory experiments on the trapping of noble gases in ice lead us to propose here that the noble gases in the atmospheres of all of the terrestrial planets are dominated by a mixture of an internal component and contribution from impacting icy planetesimals (comets). If true, this hypothesis illustrates the importance of impacts in determining the volatile inventories of these planets. PMID:11536499

  16. Theoretical Emission Spectra of Atmospheres of Hot Rocky Super-Earths

    NASA Astrophysics Data System (ADS)

    Ito, Yuichi; Ikoma, Masahiro; Kawahara, Hajime; Nagahara, Hiroko; Kawashima, Yui; Nakamoto, Taishi

    2015-03-01

    Motivated by recent detection of transiting high-density super-Earths, we explore the detectability of hot rocky super-Earths orbiting very close to their host stars. In an environment hot enough for their rocky surfaces to be molten, they would have an atmosphere composed of gas species from the magma oceans. In this study, we investigate the radiative properties of the atmosphere that is in gas/melt equilibrium with the underlying magma ocean. Our equilibrium calculations yield Na, K, Fe, Si, SiO, O, and O2 as the major atmospheric species. We compile the radiative absorption line data of those species available in the literature and calculate their absorption opacities in the wavelength region of 0.1-100 μm. Using them, we integrate the thermal structure of the atmosphere. Then, we find that thermal inversion occurs in the atmosphere because of the UV absorption by SiO. In addition, we calculate the ratio of the planetary to stellar emission fluxes during secondary eclipse, and we find prominent emission features induced by SiO at 4 μm detectable by Spitzer, and those at 10 and 100 μm detectable by near-future space telescopes.

  17. INFLAME: In-situ net flux within the atmosphere of the Earth

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.; Johnson, D. G.

    2006-12-01

    The In-situ Net FLux within the AtMosphere of the Earth (INFLAME) instrument is designed to make direct measurements of the net radiative flux within the Earth's atmosphere. Deployed on an uninhabited aerial vehicle (UAV) the INFLAME instruments will record vertical profiles of net radiative flux separately for the visible and infrared streams of radiation within the atmosphere. Upon differentiation of these vertical profiles the divergence of the net flux is obtained, which combined with the atmospheric density yields the rate of radiative heating (Kelvin per day) within the atmosphere. INFLAME offers the advantage of using a Fourier Transform Spectrometer (FTS) to directly measure the net flux, thereby avoiding potentially large errors in the derived heating rate associated with differencing separate measurements of the upwelling and downwelling fluxes of radiation. INFLAME is a new project in NASA's Instrument Incubator Program (IIP). We will describe the science motivating the measurements, the historical background to the measurements, and the INFLAME instrument now under development at the NASA Langley Research Center.

  18. The Solubility of Rock in Steam Atmospheres of the Early Earth and Hot Rocky Exoplanets

    NASA Astrophysics Data System (ADS)

    Fegley, Bruce

    2016-07-01

    Extensive experimental studies show all major rock-forming elements (e.g., Si, Mg, Fe, Ca, Al, Na, K) dissolve in steam to a greater or lesser extent. We use these results to compute chemical equilibrium abundances of rocky element - bearing gases in steam atmospheres equilibrated with silicate magma oceans. Rocky elements partition into steam atmospheres as volatile hydroxide gases (e.g., Si(OH)4, Mg(OH)2, Fe(OH)2, Ni(OH)2, Al(OH)3, Ca(OH)2, NaOH, KOH) and via reaction with HF and HCl as volatile halide gases (e.g., NaCl, KCl, CaFOH, CaClOH, FAl(OH)2) in much larger amounts than expected from their vapor pressures over volatile-free solid or molten rock at high temperatures expected for steam atmospheres on the early Earth and hot rocky exoplanets. We quantitatively compute the extent of fractional vaporization by defining gas/magma distribution coefficients and show Earth's sub-solar Si/Mg ratio may be due to loss of a primordial steam atmosphere. We conclude hot rocky exoplanets that are undergoing or have undergone escape of steam-bearing atmospheres may experience fractional vaporization and loss of Si, Mg, Fe, Ni, Al, Ca, Na, and K. This loss can modify their bulk composition, density, heat balance, and interior structure. This work was supported by NSF Astronomy Program Grant AST-1412175.

  19. Prebiotic chemistry and atmospheric warming of early Earth by an active young Sun

    NASA Astrophysics Data System (ADS)

    Airapetian, V. S.; Glocer, A.; Gronoff, G.; Hébrard, E.; Danchi, W.

    2016-06-01

    Nitrogen is a critical ingredient of complex biological molecules. Molecular nitrogen, however, which was outgassed into the Earth’s early atmosphere, is relatively chemically inert and nitrogen fixation into more chemically reactive compounds requires high temperatures. Possible mechanisms of nitrogen fixation include lightning, atmospheric shock heating by meteorites, and solar ultraviolet radiation. Here we show that nitrogen fixation in the early terrestrial atmosphere can be explained by frequent and powerful coronal mass ejection events from the young Sun--so-called superflares. Using magnetohydrodynamic simulations constrained by Kepler Space Telescope observations, we find that successive superflare ejections produce shocks that accelerate energetic particles, which would have compressed the early Earth’s magnetosphere. The resulting extended polar cap openings provide pathways for energetic particles to penetrate into the atmosphere and, according to our atmospheric chemistry simulations, initiate reactions converting molecular nitrogen, carbon dioxide and methane to the potent greenhouse gas nitrous oxide as well as hydrogen cyanide, an essential compound for life. Furthermore, the destruction of N2, CO2 and CH4 suggests that these greenhouse gases cannot explain the stability of liquid water on the early Earth. Instead, we propose that the efficient formation of nitrous oxide could explain a warm early Earth.

  20. Observational and Modeling Studies of Radiative, Chemical, and Dynamical Interactions in the Earth''s Atmosphere

    NASA Technical Reports Server (NTRS)

    Salby, Murry

    1998-01-01

    A 3-dimensional model was developed to support mechanistic studies. The model solves the global primitive equations in isentropic coordinates, which directly characterize diabatic processes forcing the Brewer-Dobson circulation of the middle atmosphere. It's numerical formulation is based on Hough harmonics, which partition horizontal motion into its rotational and divergent components. These computational features, along with others, enable 3D integrations to be performed practically on RISC computer architecture, on which they can be iterated to support mechanistic studies. The model conserves potential vorticity quite accurately under adiabatic conditions. Forced by observed tropospheric structure, in which integrations are anchored, the model generates a diabatic circulation that is consistent with satellite observations of tracer behavior and diabatic cooling rates. The model includes a basic but fairly complete treatment of gas-phase photochemistry that represents some 20 chemical species and 50 governing reactions with diurnally-varying shortwave absorption. The model thus provides a reliable framework to study transport and underlying diabatic processes, which can then be compared against chemical and dynamical structure observed and in GCM integrations. Integrations with the Langley GCM were performed to diagnose feedback between simulated convection and the tropical circulation. These were studied in relation to tropospheric properties controlling moisture convergence and environmental conditions supporting deep convection, for comparison against mechanistic integrations of wave CISK that successfully reproduce the Madden-Julian Oscillation (MJO) of the tropical circulation. These comparisons were aimed at identifying and ultimately improving aspects of the convective simulation, with the objective of recovering a successful simulation of the MJO in the Langley GCM, behavior that should be important to budgets of upper-tropospheric water vapor and

  1. Atmospheric Constituents in GEOS-5: Components for an Earth System Model

    NASA Technical Reports Server (NTRS)

    Pawson, Steven; Douglass, Anne; Duncan, Bryan; Nielsen, Eric; Ott, Leslie; Strode, Sarah

    2011-01-01

    The GEOS-S model is being developed for weather and climate processes, including the implementation of "Earth System" components. While the stratospheric chemistry capabilities are mature, we are presently extending this to include predictions of the tropospheric composition and chemistry - this includes CO2, CH4, CO, nitrogen species, etc. (Aerosols are also implemented, but are beyond the scope of this paper.) This work will give an overview of our chemistry modules, the approaches taken to represent surface emissions and uptake of chemical species, and some studies of the sensitivity of the atmospheric circulation to changes in atmospheric composition. Results are obtained through focused experiments and multi-decadal simulations.

  2. Possible cometary origin of heavy noble gases in the atmospheres of Venus, earth, and Mars

    NASA Technical Reports Server (NTRS)

    Owen, Tobias; Bar-Nun, Akiva; Kleinfeld, Idit

    1992-01-01

    Due consideration of the probable history of the Martian atmosphere, as well as noble-gas data from the Mars-derived SNC meteorites and from laboratory tests on the trapping of noble gases in ice, are the bases of the presently hypothesized domination of noble gases in the atmospheres of all terrestrial planets by a mixture of internal components and a contribution from comets. If verified, this hypothesis would underscore the significance of impacts for these planets' volatile inventories. The sizes of the hypothesized comets are of the order of 120 km for Venus and only 80 km for that which struck the earth.

  3. Thermal evolution of the earth - Effects of volatile exchange between atmosphere and interior

    NASA Technical Reports Server (NTRS)

    Mcgovern, Patrick J.; Schubert, Gerald

    1989-01-01

    The thermal history of the earth is investigated using a parameterized model of mantle convection, that includes the effects of volatile exchange between the mantle and the surface reservoir and the softening of the mantle by the dissolved volatiles. The mantle degassing rate is taken to be directly proportional to the rate of seafloor spreading which depends on the mantle heat flow. It is shown that the dependence of the mantle viscosity on the volatile content has important effects on the thermal evolution of planetary interiors and the evolution of planetary atmospheres. Degassing is compensated by an increase in temperature, while regassing is compensated by a decrease in temperature. Reasonable degassing scenarios can account for an early rapid formation of the earth's atmosphere inferred from noble gas abundances.

  4. Impact-generated atmospheric plumes: The threat to satellites in low-earth orbit

    SciTech Connect

    Boslough, M.B.; Crawford, D.A.

    1996-02-01

    Computational simulations of the impacts of comet Shoemaker-Levy 9 (SL9) fragments on Jupiter provide a framework for interpreting the observations. A reasonably consistent picture has emerged, along with a more detailed understanding of atmospheric collisional processes. The knowledge gained from the observations and simulations of SL9 has led us to consider the threat of impact-generated plumes to satellites in low-Earth orbit (LEO). Preliminary simulations suggest that impacts of a size that recur about once per century on Earth generate plumes that rise to nearly 1000 km over an area thousands of km in diameter. Detailed modeling of such plumes is needed to quantify this threat to satellites in LEO. Careful observations of high-energy atmospheric entry events using both satellite and ground- based instruments would provide validation for these computational models.

  5. Early evolution of the earth - Accretion, atmosphere formation, and thermal history

    NASA Technical Reports Server (NTRS)

    Abe, Yutaka; Matsui, Takafumi

    1986-01-01

    The thermal and atmospheric evolution of the earth growing planetesimal impacts are studied. The generation of an H2O protoatmosphere is examined, and the surface temperatures are estimated. The evolution of an impact-induced H2O atmosphere is analyzed. Consideration is given to the formation time of a 'magma ocean'and internal water budgets. The thermal history of an accreting earth is reviewed. The wet convection and greenhouse effects are discussed, and the role of Fe oxidation on the evolution of an impact-induced H2O atmopshere is described. The relationship between differentiation processes and core segregation, the H2O and FeO content of the mantle, and the origin of the hydrosphere is also examined.

  6. Atmospheric heating in an irradiated transiting super-Earth and super-Neptune

    NASA Astrophysics Data System (ADS)

    Miller, Brendan P.; Gallo, Elena; Wright, Jason; Poppenhaeger, Katja

    2016-01-01

    We present new Chandra observations of HD 97658 (13 ks) and HAT-P-11 (8 ks), obtained to determine the high-energy radiation incident upon their short-period transiting planets. HD 97658 b is a hot super-Earth with a density between Earth and ice giants, while HAT-P-11 b is a hot super-Neptune orbiting an active K4 star. Our measurement of the stellar X-ray (and UV, from Swift) luminosities provides a current epoch estimate of atmospheric heating. We discuss whether these planets are likely to have experienced significant mass loss through atmospheric evaporation over their total lifetimes. These observations provide essential empirical input for understanding and modeling the potential evolutionary transformation of hot gas giants into less massive and more dense remnants.

  7. Comment on the paper 'On the influx of small comets into the earth's upper atmosphere'

    NASA Technical Reports Server (NTRS)

    Soter, Steven

    1987-01-01

    The possibility that comets containing up to 100 tons of ice encounter the earth's atmosphere at a rate of one every 20 min is discussed. Cometary 'hail storms' were proposed to explain observed regular transient decreases in the atmospheric UV dayglow intensity. The decreases take the form of dark 'holes' up to 50 km across. The probability that clouds of objects assumed to be as dark as the nucleus of Comet Halley between the earth and moon would be detectable by ground-based electrooptical deep space telescopes is considered. Conflicting projections of the number of objects which would be detected per hour are examined. High correlations are noted between cometary passages (Comets Encke, Tuttle, Tempel) and intervals of meteor showers (Taurids, Leonids, Geminis, etc.). The holes, however, are not correlated or coincident with the showers. It is suggested that dedicated searches for the unclassified dark objects be carried out in November, when cometary fluxes are high.

  8. Concept of a space optoelectronic system for environmental monitoring of the near-earth space, atmosphere, and earth surface

    NASA Astrophysics Data System (ADS)

    Eltsov, Anatoli V.; Karasev, Vladimir I.; Kolotkov, Vjacheslav V.; Kondranin, Timothy V.

    1997-06-01

    The sharp increase of the man-induced pressure on the environment and hence the need to predict and monitor natural anomalies makes global monitoring of the ecosphere of planet Earth an issue of vital importance. The notion of the ecosphere covers three basic shells closely interacting with each other: the near-Earth space, the atmosphere and the Earth surface. In the near-Earth space (covering 100 to 2000 km altitudes) the primary objects of monitoring are: functioning artificial space objects, the fragments of their constructions or space rubbish (which by estimation amounts to 3.5 million pieces including 30,000 to 70,000 objects having dimensions sufficient for heavy damaging or even destroying functioning space objects) and objects of space origin (asteroids, meteorites and comets) whose trajectories come closely enough to the Earth. Maximum concentrations of space rubbish observed on orbits with altitudes of 800, 1000 and 1500 km and inclinations of 60 to 100 deg. are related in the first place to spacecraft launch requirements. Taking into account the number of launches implemented by different countries in the framework of their own space programs the probability of collision of functioning spacecraft with space rubbish may be estimation increase from (1.5 - 3.5)% at present to (15 - 40)% by 2020. Besides, registration of space radiation flow intensity and the solar activity is no less important in this space area. Subject to control in the atmosphere are time and space variations in temperature fields, humidity, tracing gas concentrations, first of all ozone and greenhouse gases, the state of the cloud cover, wind velocity, etc. The range of objects to be under environmental management of Earth surface is just as diverse and essentially should include the state of the surface and the near-surface layer of seas and oceans, internal reservoirs, the cryosphere and the land surface along with vegetation cover, natural resources and human activities. No matter

  9. Transmission and total reflection of subhertz electromagnetic waves at the earth-atmosphere interface

    SciTech Connect

    Shiozawa, Toshiyuki

    2010-12-15

    For the purpose of providing for a theoretical background for the study of electromagnetic fields generated by precursory effects of earthquakes, the problem of transmission and total reflection at the earth-atmosphere interface is investigated in detail for a subhertz plane electromagnetic wave incident from the earth's crust. The term ''subhertz'' means 'below 1 Hz'. First, for the special case of normal incidence, the overall power transmission coefficient at the earth-atmosphere interface is found to take a maximum value at a definite frequency f{sub 0} which is inversely proportional to the square of the depth of a virtual hypocenter. A typical value of f{sub 0} falls around 0.01 Hz. For oblique incidence as well, this feature of the overall power transmission coefficient is retained except in the vicinity of the critical angle of incidence for the H-wave. At the critical angle of incidence, the power flow carried by a surface wave along the interface becomes anomalously large for the H-wave. However, over a wide range of angles of incidence greater than the critical angle, the power flow carried by the E-wave exceeds that carried by the H-wave by orders of magnitude. Finally, the energy conservation relations for the incident, reflected, and transmitted waves at the earth-atmosphere interface are discussed. For an incident wave coming from the earth's crust, the interactive power between the incident and reflected waves plays a crucial role for the conservation of energy at the interface.

  10. Mapping the downwelling atmospheric radiation at the Earth's surface: A research strategy

    NASA Technical Reports Server (NTRS)

    Raschke, E.

    1986-01-01

    A strategy is presented along with background material for determining downward atmospheric radiation at the Earth's surface on a regional scale but over the entire globe, using available information on the temperature and humidity of the air near the ground and at cloud base altitudes. Most of these parameters can be inferred from satellite radiance measurements. Careful validation of the derived radiances will be required using ground-based direct measurements of radiances, to avoid systematic biases of these derived field quantities.