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Sample records for atmospheric experiment recherche

  1. Lunar atmospheric composition experiment

    NASA Technical Reports Server (NTRS)

    Hoffman, J. H.

    1975-01-01

    Apollo 17 carried a miniature mass spectrometer, called the Lunar Atmospheric Composition Experiment (LACE), to the moon as part of the Apollo Lunar Surface Experiments Package (ALSEP) to study the composition and variations in the lunar atmosphere. The instrument was successfully deployed in the Taurus-Littrow Valley with its entrance aperture oriented upward to intercept and measure the downward flux of gases at the lunar surface. During the ten lunations that the LACE operated, it produced a large base of data on the lunar atmosphere, mainly collected at night time. It was found that thermal escape is the most rapid loss mechanism for hydrogen and helium. For heavier gases, photoionization followed by acceleration through the solar wind electric field accounted for most of the loss. The dominant gases on the moosn were argon and helium, and models formed for their distribution are described in detail. It is concluded that most of the helium in the lunar atmosphere is of solar wind origin, and that there also exist very small amounts of methane, ammonia, and carbon dioxide.

  2. Atmospheric Climate Experiment Plus

    NASA Astrophysics Data System (ADS)

    Lundahl, K.

    ACE+ is an atmospheric sounding mission using radio occultation techniques and is a combination of the two Earth Explorer missions ACE and WATS earlier proposed to ESA. ACE was highly rated by ESA in the Call for Earth Explorer Opportunity Missions in 1999 and was prioritised as number three and selected as a "hot-stand-by". A phase A study was carried out during 2000 and 2001. ACE will observe atmospheric parameters using radio occultations from an array of 6 micro-satellites which track the L- band signal of GPS satellites to map the detailed refractivity and thermal structure of the global atmosphere from surface to space. Water vapour and wind in Atmospheric Troposphere and Stratosphere WATS was the response to ESA's Call for Ideas for the next Earth Explorer Core Missions in 2001. WATS combines ACE GPS atmospheric occultations and LEO-LEO cross-link occultations. Cross-links strongly enhance the capability of measuring humidity relative to the ACE mission. The Earth Science Advisory Committée at ESA noted that the LEO-GNSS occultation technique is already well established through several missions in recent years and could not recommend WATS for a Phase A study as an Earth Explorer Core Mission. The ESAC was, however, deeply impressed by the LEO-LEO component of the WATS proposal and would regard it as regrettable if this science would be lost and encourages the ACE/WATS team to explore other means to achieve its scientific goal. ACE+ is therefore the response to ESA's 2nd Call for Earth Explorer Opportunity Missions in 2001 and will contribute in a significant manner to ESA's Living Planet Programme. ACE+ will considerably advance our knowledge about atmosphere physics and climate change processes. The mission will demonstrate a highly innovative approach using radio occultations for globally measuring profiles of humidity and temperature throughout the atmosphere and stratosphere. A constellation of 4 small satellites, tracking L-band GPS/GALILEO signals and

  3. NASA's atmospheric variability experiments /AVE/

    NASA Technical Reports Server (NTRS)

    Hill, K.; Turner, R. E.

    1977-01-01

    A series of seven mesoscale experiments were conducted under the NASA program, Atmospheric Variability Experiments (AVE). Rawinsonde, satellite, aircraft, and ground observations were recorded during specially selected meteorological periods lasting from 1 to 3 days. Details are presented for each AVE relative to observation times, experiment size and location, and significant weather. Some research results based on the use of these AVE data are referenced. These include contributions to regional numerical prediction; relations between wind shears, instability, and thunderstorm motion and development; relations between moisture and temperature and the probability of convection; retrieval of tropospheric temperature profiles from cloud-contaminated satellite data; variation of convection intensity as a result of atmospheric variability; and effects of cloud rotation on their trajectories.

  4. Atmospheric variability experiment /AVE II/ pilot experiment

    NASA Technical Reports Server (NTRS)

    Turner, R. E.; Scroggins, J. R.

    1974-01-01

    The Atmospheric Variability Experiment (AVE II) was conducted in May 1974. Rawinsonde releases were made at 54 upper-air stations in two thirds of the eastern U.S. at 3-hr intervals for a 24-hr period. Radar data were obtained from 11 stations located near the center of the observational area, and as many data as possible were collected from the Nimbus 5, NOAA 2, ATS-3, and DMSP satellites. The present paper provides an overview of the experiment and describes how the user community can obtain copies of the data.

  5. The Atmospheric Chemistry Experiment (ACE)

    NASA Astrophysics Data System (ADS)

    Bernath, P. F.

    2017-01-01

    The Atmospheric Chemistry Experiment (ACE), also called SCISAT, is a Canadian-led small satellite mission for remote sensing of the Earth's atmosphere. ACE was launched into a low Earth circular orbit by NASA on August 12, 2003 and it continues to function nominally. The ACE instruments are a high spectral resolution (0.02 cm-1) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 μm (750-4400 cm-1), a spectrophotometer known as Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (MAESTRO) with wavelength coverage of 285-1020 nm and two filtered detector arrays to image the Sun at 0.525 and 1.02 μm. ACE operates in solar occultation mode to provide altitude profiles of temperature, pressure, atmospheric extinction and the volume mixing ratios (VMRs) for several dozen molecules and related isotopologues. This paper presents a mission overview and a summary of selected scientific results.

  6. Atmospheric Entry Experiments at IRS

    NASA Astrophysics Data System (ADS)

    Auweter-Kurtz, M.; Endlich, P.; Herdrich, G.; Kurtz, H.; Laux, T.; Löhle, S.; Nazina, N.; Pidan, S.

    2002-01-01

    Entering the atmosphere of celestial bodies, spacecrafts encounter gases at velocities of several km/s, thereby being subjected to great heat loads. The thermal protection systems and the environment (plasma) have to be investigated by means of computational and ground facility based simulations. For more than a decade, plasma wind tunnels at IRS have been used for the investigation of TPS materials. Nevertheless, ground tests and computer simulations cannot re- place space flights completely. Particularly, entry mission phases encounter challenging problems, such as hypersonic aerothermodynamics. Concerning the TPS, radiation-cooled materials used for reuseable spacecrafts and ablator tech- nologies are of importance. Besides the mentioned technologies, there is the goal to manage guidance navigation, con- trol, landing technology and inflatable technologies such as ballutes that aim to keep vehicles in the atmosphere without landing. The requirement to save mass and energy for planned interplanetary missions such as Mars Society Balloon Mission, Mars Sample Return Mission, Mars Express or Venus Sample Return mission led to the need for manoeuvres like aerocapture, aero-breaking and hyperbolic entries. All three are characterized by very high kinetic vehicle energies to be dissipated by the manoeuvre. In this field flight data are rare. The importance of these manoeuvres and the need to increase the knowledge of required TPS designs and behavior during such mission phases point out the need of flight experiments. As result of the experience within the plasma diagnostic tool development and the plasma wind tunnel data base, flight experiments like the PYrometric RE-entry EXperiment PYREX were developed, fully qualified and successfully flown. Flight experiments such as the entry spectrometer RESPECT and PYREX on HOPE-X are in the conceptual phase. To increase knowledge in the scope of atmospheric manoeuvres and entries, data bases have to be created combining both

  7. Combustible caramel pour reacteurs de recherche: Experience acquise en fabrication, controles et irradiation du coeur d'osiris

    NASA Astrophysics Data System (ADS)

    de Contenson, Ghislain; Foulquier, Henri; Trotabas, Maria; Vignesoult, Nicole; Cerles, Jean-Marie; Delafosse, Jacques

    1982-04-01

    L'un des aboutissements des différentes actions menées en France concernant la conception, la fabrication et le développement des combustibles nucléaires a été la mise au point par le CEA d'un combustible de type plaque (combustible CARAMEL) susceptible d'être adapté a différentes catégories de réacteurs à eau (réacteur de puissance, propulsion navale, chauffage urbain, pile de recherche). Ces travaux ont été couronnés par la réalisation de tout un coeur et des recharges du réacteur de recherche à hautes performances, Osiris, à Saclay. L'ancien combustible en alliage U Al fortement enrichi a eté remplacé par un combustible caramel de faible enrichissement (7%), non proliférant. Ce nouveau coeur fonctionne avec satisfaction, depuis janvier 1980. Après une brève description des caractéristiques du combustible caramel et de ses principaux avantages, on présente sa fabrication ainsi que l'ensemble des contrôles de qualité auxquels il est soumis. Le programme de qualification ainsi que les principaux résultáts qui en ont été tirés sont exposés. On décrit également le programme de suivi du combustible en pile dont le but est de s'assurer du bon comportement du combustible sous irradiation. Le bon fonctionnement d'Osiris, qui a terminé 11 cycles d'irradiation le 21 avril 1981, a permis de montrer le bien fondé des choix effectués et l'excellent comportement de l'élément combustible dans les conditions pourtant sévères d'un réacteur de recherche à hautes performances.

  8. The Radiometer Atmospheric Cubesat Experiment

    NASA Astrophysics Data System (ADS)

    Lim, B.; Bryk, M.; Clark, J.; Donahue, K.; Ellyin, R.; Misra, S.; Romero-Wolf, A.; Statham, S.; Steinkraus, J.; Lightsey, E. G.; Fear, A.; Francis, P.; Kjellberg, H.; McDonald, K.

    2014-12-01

    The Jet Propulsion Laboratory (JPL) has been developing the Radiometer Atmospheric CubeSat Experiment (RACE) since 2012, which consists of a water vapor radiometer integrated on a 3U CubeSat platform. RACE will measure 2 channels of the 183 GHz water vapor line, and will be used to validate new low noise amplifier (LNA) technology and a novel amplifier based internal calibration subsystem. The 3U spacecraft is provided by the University of Texas at Austin's Satellite Design Laboratory. RACE will advance the technology readiness level (TRL) of the 183 GHz receiver subsystem from TRL 4 to TRL 6 and a CubeSat 183 GHz radiometer system from TRL 4 to TRL 7. Measurements at 183 GHz are used to retrieve integrated products and vertical profiles of water vapor. Current full scale satellite missions that can utilize the technology include AMSU, ATMS, SSMIS and Megha-Tropiques. The LNAs are designed at JPL, based on a 35 nm indium phosphide (InP) high-electron-mobility transistors (HEMT) technology developed by Northrop Grumman. The resulting single chip LNAs require only 25 mW of power. Current pre-launch instrument performance specifications include an RF gain of over 30 dB and a room noise figure of < 9.5 dB. The noise figure is dominated by the insertion loss of the Dicke switch which at these frequencies are > 5dB. If a coupler based calibration system is shown to be sufficient, future receiver systems will have noise figures < 4 dB. The gain and noise figure variation over temperature is approximately 0.55 dB/K. The NEDT of the system is < 1K, and on orbit performance is expected to improve due to the thermal environment. The current system is configured for direct detection to reduce power consumption by eliminating the need for a local oscillator. A 2012 NASA CubeSat Launch Initiative (CSLI) selection, RACE is manifested for launch on the Orbital 3 (Orb-3) mission scheduled for October 2014. RACE will be deployed from the International Space Station (ISS) by NanoRacks.

  9. Atmospheric microphysical experiments on an orbital platform

    NASA Technical Reports Server (NTRS)

    Eaton, L. R.

    1974-01-01

    The Zero-Gravity Atmospheric Cloud Physics Laboratory is a Shuttle/Spacelab payload which will be capable of performing a large range of microphysics experiments. This facility will complement terrestrial cloud physics research by allowing many experiments to be performed which cannot be accomplished within the confines of a terrestrial laboratory. This paper reviews the general Cloud Physics Laboratory concept and the experiment scope. The experimental constraints are given along with details of the proposed equipment. Examples of appropriate experiments range from three-dimensional simulation of the earth and planetary atmosphere and of ocean circulation to cloud electrification processes and the effects of atmospheric pollution materials on microphysical processes.

  10. Atmospheric boundary layer response to sea surface temperatures during the SEMAPHORE experiment

    NASA Astrophysics Data System (ADS)

    Giordani, Hervé; Planton, Serge; Benech, Bruno; Kwon, Byung-Hyuk

    1998-10-01

    The sensitivity of the marine atmospheric boundary layer (MABL) subjected to sea surface temperatures (SST) during the Structure des Echanges Mer-Atmosphere, Proprietes des Heterogeneites Oceaniques: Recherche Experimentale (SEMAPHORE) experiment in 1993 has been studied. Atmospheric analyses produced by the Action de Recherche, Petite Echelle, Grande Echelle (ARPEGE) operational model at the French meteorological weather service assimilated data sets collected between October 7 and November 17, 1993, merged with the Global Telecommunication System (GTS) data. Analyses were validated against independent data from aircraft instruments collected along a section crossing the Azores oceanic front, not assimilated into the model. The responses of the mean MABL in the aircraft cross section to changes in SST gradients of about 1°C/100 km were the presence of an atmospheric front with horizontal gradients of 1°C/100 km and an increase of the wind intensity from the cold to the warm side during an anticyclonic synoptic situation. The study of the spatiotemporal characteristics of the MABL shows that during 3 days of an anticyclonic synoptic situation the SST is remarkably stationary because it is principally controlled by the Azores ocean current, which has a timescale of about 10 days. However, the temperature and the wind in the MABL are influenced by the prevailing atmospheric conditions. The ocean does not appear to react to the surface atmospheric forcing on the timescale of 3 days, whereas the atmospheric structures are modified by local and synoptic-scale advection. The MABL response appears to be much quicker than that of the SSTs. The correlation between the wind and the thermal structure in the MABL is dominated by the ageostrophic and not by the geostrophic component. In particular, the enhancement of the wind on either side of the SST front is mainly due to the ageostrophic component. Although the surface heat fluxes are not the only cause of ageostrophy, the

  11. Experiments to Study Our Atmospheric Environment

    NASA Astrophysics Data System (ADS)

    Marti, James

    The teacher of an introductory physics and chemistry course has many choices when it comes to laboratory manuals. Not so with atmospheric science: texts devoted to learning the subject in a lab setting are limited in number and often in scope. A large portion of the available lab texts concentrate solely on exercises in synoptic analysis and forecasting skills, which while important do not convey the full range of the science and its applications. That is why Steven Businger's Experiments to Study Our Atmospheric Environment stands out among recent books devoted to teaching atmospheric science in the lab.

  12. Recherche de charginos et neutralinos dans le canal dimuon de meme signe aupres de l'experience DØ - FNAL

    SciTech Connect

    Lesne, Vincent

    2006-07-01

    Dans le cadre du modele mSUGRA qui decrit un mecanisme de brisure simple de la supersym etrie, des sparticules avec des masses au-del a des limites fixees par les experiences de LEP II peuvent etre produites au Tevatron, collisionneur p$\\bar{p}$ delivrant une energie de 1.96 TeV dans le centre de masse. Un canal privilegie pour la d´ecouverte de la supersymetrie au Tevatron est la production associee du plus leger chargino, $\\tilde{χ}$$±\\atop{1}$ , et du second plus leger neutralino, $\\tilde{χ}$$0\\atop{2}$ . Les modes de desintegration leptoniques, $\\tilde{χ}$$0\\atop{2}$ → $\\tilde{χ}$$0\\atop{1}$ ℓ+- et $\\tilde{χ}$$±\\atop{1}$ → $\\tilde{χ}$$0\\atop{1}$ ℓ±νl, conduisent a une signature claire avec trois leptons et un quantite significative d’energie transverse manquante.

  13. Next-generation atmospheric neutrino experiments

    NASA Astrophysics Data System (ADS)

    Kouchner, Antoine

    2014-09-01

    A short review on the next-generation experiments aiming to study the neutrinos produced in cosmic-ray induced atmospheric showers is presented. The projects currently proposed rely on different complementary detection techniques, from the successful water Cherenkov and magnetized tracko-calorimeter techniques to the more innovative Liquid Argon technology. As all of the proposed detectors must be deeply buried to mitigate the atmospheric muon background, many experiments are expected to be placed deep underground. Following the neutrino telescope approach, the largest ones will be located deep under the sea/ice. Several future projects are part of a wider physics program which includes a neutrino beam. For such cases, the focus is put on the expected performances with only using atmospheric neutrinos. The main physics thread of the review is the question of the determination of the ordering of the neutrino mass eigenstates, referred to as the neutrino mass hierarchy. This falls into the broader context of the precise measurement of the neutrino mixing parameters. The expected reach of the future planned detectors in this respect is also addressed.

  14. Advanced Global Atmospheric Gases Experiment (AGAGE)

    NASA Technical Reports Server (NTRS)

    Prinn, Ronald G.; Kurylo, Michael (Technical Monitor)

    2004-01-01

    We seek funding from NASA for the third year (2005) of the four-year period January 1, 2003 - December 31, 2006 for continued support of the MIT contributions to the multi-national global atmospheric trace species measurement program entitled Advanced Global Atmospheric Gases Experiment (AGAGE). The case for real-time high-frequency measurement networks like AGAGE is very strong and the observations and their interpretation are widely recognized for their importance to ozone depletion and climate change studies and to verification issues arising from the Montreal Protocol (ozone) and Kyoto Protocol (climate). The proposed AGAGE program is distinguished by its capability to measure over the globe at high frequency almost all of the important species in the Montreal Protocol and almost all of the significant non-CO2 gases in the Kyoto Protocol.

  15. The Atmospheric Lifetime Experiment. II - Calibration

    NASA Technical Reports Server (NTRS)

    Rasmussen, R. A.; Lovelock, J. E.

    1983-01-01

    The calibration standards used in the Atmospheric Lifetime Experiment (ALE) for CFCl3, CF2Cl2, CH3CCl3, and CCl4 are described. This includes the preparation of the primary standards by static dilution and their propagation and stability for the period 1977-1982. Two independent assessments of the absolute concentrations of the primary standards used to initiate the ALE measurements in 1977-1978 are reported. For consistency in the ALE program the values assigned to the primary standards and subsequent working standards used in the field were not altered during the experiment when results of better estimates of the original concentration values were obtained. Rather, the appropriate factors by which the ALE mixing ratios for a given species should be multiplied to obtain the best estimate of the current concentration of a given species, are provided.

  16. The Atmospheric Lifetime Experiment. II - Calibration

    NASA Astrophysics Data System (ADS)

    Rasmussen, R. A.; Lovelock, J. E.

    1983-10-01

    The calibration standards used in the Atmospheric Lifetime Experiment (ALE) for CFCl3, CF2Cl2, CH3CCl3, and CCl4 are described. This includes the preparation of the primary standards by static dilution and their propagation and stability for the period 1977-1982. Two independent assessments of the absolute concentrations of the primary standards used to initiate the ALE measurements in 1977-1978 are reported. For consistency in the ALE program the values assigned to the primary standards and subsequent working standards used in the field were not altered during the experiment when results of better estimates of the original concentration values were obtained. Rather, the appropriate factors by which the ALE mixing ratios for a given species should be multiplied to obtain the best estimate of the current concentration of a given species, are provided.

  17. Advanced Global Atmospheric Gases Experiment (AGAGE)

    NASA Technical Reports Server (NTRS)

    Weiss, R. F.

    1998-01-01

    The Advanced Global Atmospheric Gases Experiment (AGAGE) is an ongoing research project, for which the work carried out by the Scripps Institution of Oceanography. Due to the need to complete AGAGE activities specifically funded under NAGW-2034 that had been delayed, a no-cost extension to this grant was obtained, creating an overlap period between the two grants. Because the AGAGE project is continuing, and a Final Project Report is required only because of the change in grant numbers, it is most appropriate to submit for this report the Introduction and Accomplishments sections which appear on pages 1-62 of the October 1998 AGAGE renewal proposal. A copy of the complete proposal is attached.

  18. Pacific Atmospheric Sulfur Experiment (PASE): An Overview

    NASA Astrophysics Data System (ADS)

    Bandy, A. R.; Blomquist, B.; Huebert, B.; Howell, S.; Clarke, T.; Hudson, J.; Faloona, I.; Wang, Y.; Mauldin, R. L.; Heikes, B.; Merrill, J.; O'Sullivan, D.

    2008-12-01

    The Pacific Atmospheric Sulfur Experiment (PASE) was a study of the chemistry of sulfur in a cloud free region of the equatorial Pacific Ocean. The experiment was conducted aboard the NSF C130 just east of Christmas Island during August and early September of 2007 in the prevailing southeasterly trade wind flow. PASE is envisioned as the first of a series of experiments focused on developing an understanding of how the chemistry of sulfur affects climate in general but especially with respect to its impact on cloud chemistry and physics. Being the first of this series, PASE was focused on (but not limited to) clear air to narrow the scope of the science to control costs and to reflect the fact that most of the available instrumentation cannot make effective measurements in clouds. PASE is unique in that it brought together several instruments (SO2, DMS, O3 and H2O) that make measurements fast enough to permit the computation of vertical fluxes by eddy covariance allowing the flux terms in chemical budgets to be determined quantitatively. The PASE instrument payload also made a large suite of slower measurements including but not limited to OH, HO2, RO2, H2SO4, methane sulfonic acid (MSA), H2O2, CH3COOH, thermally resolved CN(>15nm), ultrafine CN (>3 nm), bulk aerosol composition, and cloud condensation nuclei (CCN). The high rate instruments enabled quantification of the vertical exchange that could be generalized to estimate the mixing of the slower analytes. One of the surprising results from PASE was the large and very steady levels of CCN observed throughout the experiment. Furthermore, the vertical gradient indicated that boundary layer venting via shallow convection was a persistent sink of the CCN. Taken in concert the unique data set renders a picture of marine air that has not been purged by precipitation in a long while, allowing it to build up large amounts of volatile sulfur in the condensed phase and providing a superb environment to investigate

  19. The Atmospheric Neutral Density Experiment (ANDE)

    DTIC Science & Technology

    2009-01-01

    scaling the B term down to fit the observations. The ANDERR data provide a global climate monitoring metric, which showed a consistent overestimation2... ve d C D MAA FCal ANDERR CD vs. Time (a) (d) (b) (e) (c) 142 2009 NRL REVIEW ATMOSPHERIC SCIENCE AND TECHNOLOGY FIGURE 8 The ANDE wind and temperature spectrometer.

  20. A Spectacular Experiment Exhibiting Atmospheric Pressure

    ERIC Educational Resources Information Center

    Le Noxaïc, Armand

    2014-01-01

    The experiment described here is fairly easy to reproduce and dramatically shows the magnitude of ambient air pressure. Two circular plates of aluminum are applied one against the other. How do you make their separation very difficult? With only the help of an elastic band! You don't have to use a vacuum pump for this experiment.

  1. A Spectacular Experiment Exhibiting Atmospheric Pressure

    ERIC Educational Resources Information Center

    Le Noxaïc, Armand

    2014-01-01

    The experiment described here is fairly easy to reproduce and dramatically shows the magnitude of ambient air pressure. Two circular plates of aluminum are applied one against the other. How do you make their separation very difficult? With only the help of an elastic band! You don't have to use a vacuum pump for this experiment.

  2. Mission and sampling analyses for atmospheric satellite experiments

    NASA Technical Reports Server (NTRS)

    Harrison, Edwin F.

    1990-01-01

    Orbital analyses, instrument-viewing geometry studies, and sampling simulations are performed to define mission concepts for advanced atmospheric research satellite experiments. These analyses are conducted in collaboration with NASA Headquarters and working groups consisting of atmospheric scientists and experiment developers. Analytical techniques are developed and used to optimize geographical coverage, sensor-viewing geometries, data gathering strategies, sampling schemes, orbital characteristics, satellite launch times, and operational modes of the various experiments and mission concepts. Short-term (7 day) Shuttle Missions, the Upper Atmosphere Research Satellite (UARS), and multisatellite missions such as the Earth Observing System (EOS) are being studied. Atmospheric experiments which are being analyzed include nadir-viewing sounders, limb-emission scanners, laser systems, and solar-occultation techniques.

  3. 3-flavor oscillations with current and future atmospheric experiments

    NASA Astrophysics Data System (ADS)

    Kearns, Ed

    2017-01-01

    Atmospheric neutrinos are comprised of both electron and muon neutrinos with a wide range of energies and baselines. In addition, those that pass through the earth are subject to substantial matter effects. Therefore, atmospheric neutrinos are a natural laboratory for exploring 3-flavor neutrino oscillation with sensitivity to the unknown mass ordering and CP violating phase. I will review the results from current experiments and the prospects for future experiments.

  4. The San Marco 3 neutral atmosphere composition experiment

    NASA Technical Reports Server (NTRS)

    Pelz, D. T.; Newton, G. P.; Kasprzak, W. T.; Clem, T. D.

    1973-01-01

    The experimental instrumentation of the San Marco 3 satellite is described along with the calibration and operation. The instrumentation for the following experiments was included: an air density experiment for measuring the instantaneous drag force, and thus the neutral particle total mass density; a neutral atmosphere composition experiment for measuring the densities of helium, atomic and molecular oxygen, molecular nitrogen and argon; and a neutral atmosphere temperature experiment to determine the gas kinetic temperature by measuring molecular nitrogen density variations in an orificed spherical chamber as a function of angle of attack.

  5. The Atmospheric Chemistry Experiment (ACE): Mission Overview

    NASA Astrophysics Data System (ADS)

    Bernath, P. F.; Boone, C.; Walker, K.; McLeod, S.; Nassar, R.

    2003-12-01

    The ACE mission goals are: (1) to measure and to understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere, with a particular emphasis on the Arctic region; (2) to explore the relationship between atmospheric chemistry and climate change; (3) to study the effects of biomass burning in the free troposphere; (4) to measure aerosol number density, size distribution and composition in order to reduce the uncertainties in their effects on the global energy balance. ACE will make a comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols, and temperature by solar occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) gives ACE coverage of tropical, mid-latitudes and polar regions. The solar occultation advantages are high sensitivity and self-calibration. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4100 cm-1) will measure the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. The ACE concept is derived from the now-retired ATMOS FTS instrument, which flew on the Space Shuttle in 1985, 1992, 1993, 1994. Climate-chemistry coupling may lead to the formation of an Arctic ozone hole. ACE will provide high quality data to confront these model predictions and will monitor polar chemistry as chlorine levels decline. The ACE-FTS can measure water vapor and HDO in the tropical tropopause region to study dehydration and strat-trop exchange. The molecular signatures of massive forest fires will evident in the ACE infrared spectra. The CO2 in our spectra can be used to either retrieve atmospheric pressure or (if the instrument pointing knowledge proves to be satisfactory) for an independent retrieval of a CO2 profile for carbon cycle science. Aerosols and clouds will be monitored using the extinction of solar radiation at

  6. The Atmospheric Chemistry Experiment (ACE): Mission Overview

    NASA Astrophysics Data System (ADS)

    Bernath, P.

    2003-04-01

    The ACE mission goals are: (1) to measure and to understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere, with a particular emphasis on the Arctic region; (2) to explore the relationship between atmospheric chemistry and climate change; (3) to study the effects of biomass burning in the free troposphere; (4) to measure aerosol number density, size distribution and composition in order to reduce the uncertainties in their effects on the global energy balance. ACE will make a comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols, and temperature by solar occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) will give ACE coverage of tropical, mid-latitudes and polar regions. The solar occultation advantages are high sensitivity and self-calibration. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4100 cm-1) will measure the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. The ACE concept is derived from the now-retired ATMOS FTS instrument, which flew on the Space Shuttle in 1985, 1992, 1993, 1994. Climate-chemistry coupling may lead to the formation of an Arctic ozone hole. ACE will provide high quality data to confront these model predictions and will monitor polar chemistry as chlorine levels decline. The ACE-FTS can measure water vapor and HDO in the tropical tropopause region to study dehydration and strat-trop exchange. The molecular signatures of massive forest fires will evident in the ACE infrared spectra. The CO_2 in our spectra can be used to either retrieve atmospheric pressure or (if the instrument pointing knowledge proves to be satisfactory) for an independent retrieval of a CO_2 profile for carbon cycle science. Aerosols and clouds will be monitored using the extinction of solar

  7. Shuttle Coherent Atmospheric Lidar Experiment (SCALE)

    NASA Technical Reports Server (NTRS)

    Bilbro, J.; Beranek, R.; Fitzjarrald, D.; Mabry, J.

    1987-01-01

    The results of a study to design and accommodate a simplified version of a coherent lidar system capable of performing tropospheric wind measurements are outlined. The following topics are addressed: system sensitivity, orbital analysis, science experiments, preliminary system design, accommodations, and the space qualification of a 2J CO2 laser.

  8. Atmospheric Turbulence Statistics from GOLD Experiments

    NASA Technical Reports Server (NTRS)

    Jeganathan, Muthu; Wilson, Keith; Lesh, Jim

    1996-01-01

    Ground-Orbiter Lasercomm Demonstration (GOLD) includes the following: (1) Optical communication experiments between Table Mountain Observatory (TMF) and Japanese Engineering Test Satellite (ETS-VI); (2) International cooperative effort between NASA, NASDA, CRL and JPL; and (3) Phase 1 transmissions from October 1995 to January 1996 and Phase 2 transmissions from March 1996 to May 1996.

  9. Atmospheric Turbulence Statistics from GOLD Experiments

    NASA Technical Reports Server (NTRS)

    Jeganathan, Muthu; Wilson, Keith; Lesh, Jim

    1996-01-01

    Ground-Orbiter Lasercomm Demonstration (GOLD) includes the following: (1) Optical communication experiments between Table Mountain Observatory (TMF) and Japanese Engineering Test Satellite (ETS-VI); (2) International cooperative effort between NASA, NASDA, CRL and JPL; and (3) Phase 1 transmissions from October 1995 to January 1996 and Phase 2 transmissions from March 1996 to May 1996.

  10. The Atmospheric Chemistry Experiment (ACE): MLT Results

    NASA Astrophysics Data System (ADS)

    Bernath, Peter

    2010-05-01

    ACE (also known as SCISAT) is making a comprehensive set of simultaneous measurements of numerous trace gases, thin clouds, aerosols and temperature by solar occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) gives ACE coverage of tropical, mid-latitudes and polar regions. The primary instrument is a high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4400 cm-1). ACE was launched by NASA on 12 August 2003 for a nominal 2-year mission; after 6 years on orbit the ACE-FTS performance is still excellent. The first results of ACE have been presented in a special issue of Geophysics Research Letters (http://www.agu.org/journals/ss/ACECHEM1/) in 2005 and recently a special issue on ACE validation has been prepared for Atmospheric Chemistry and Physics (http://www.atmos-chem-phys.net/special_issue114.html) by K. Walker and K. Strong; more information can be found at http://www.ace.uwaterloo.ca. The ACE mission goals were initially focussed mainly on polar ozone chemistry, and more recently have shifted more to the troposphere where organic pollutants such as methanol and formaldehyde have been detected. ACE makes limb observations from about 5 km (cloud free scenes) up to nearly 150 km in the lower thermosphere, where CO2 absorption is still weakly detectable. This talk will review ACE-FTS results in the mesosphere and lower thermosphere. Topics covered will include the mesospheric descent of NOx in the polar winter, spectra of polar mesospheric clouds, concentration profiles of CO2 (which do not match model predictions), and combined Odin-Osiris/ACE-FTS observations.

  11. The Atmospheric Chemistry Experiment (ACE): Latest Results

    NASA Astrophysics Data System (ADS)

    Bernath, P.

    2008-12-01

    ACE (also known as SCISAT) is making a comprehensive set of simultaneous measurements of numerous trace gases, thin clouds, aerosols and temperature by solar occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) gives ACE coverage of tropical, mid-latitudes and polar regions. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4400 cm-1) is measuring the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. Aerosols and clouds are being monitored using the extinction of solar radiation at 0.525 and 1.02 microns as measured by two filtered imagers as well as by their infrared spectra. A dual spectrograph called MAESTRO extends the wavelength coverage to the 400-1000 nm spectral region. The principal investigator for MAESTRO is T. McElroy of the Meteorological Service of Canada. The FTS and imagers have been built by ABB-Bomem in Quebec City, while the satellite bus has been made by Bristol Aerospace in Winnipeg. ACE is part of the Canadian Space Agency's small satellite program, and was launched by NASA on 12 August 2003 for a nominal 2-year mission. The first results of ACE have been presented in a special issue of Geophysics Research Letters (http://www.agu.org/journals/ss/ACECHEM1/) in 2005 and recently a special issue on ACE validation has been prepared for Atmospheric Chemistry and Physics by K. Walker and K. Strong. A mission overview and status report will be presented. Science results for a few selected topics including the detection of organic molecules such as methanol and formaldehyde in the troposphere will be discussed.

  12. Parametrization of Fresnel returns in middle-atmosphere radar experiments

    NASA Technical Reports Server (NTRS)

    Rastogi, P. K.

    1983-01-01

    Weak reflections from sharp discontinuities in radio refractivity are usually invoked to explain the results of radio propagation experiments. The characteristics of refractivity structures required to produce Fresnel returns are examined and experimental evidence for Fresnel returns in middle-atmosphere radar experiments is reviewed. The consequences of these returns on estimating the turbulence and wind parameters are outlined.

  13. Airborne experiment results for spaceborne atmospheric synchronous correction system

    NASA Astrophysics Data System (ADS)

    Cui, Wenyu; Yi, Weining; Du, Lili; Liu, Xiao

    2015-10-01

    The image quality of optical remote sensing satellite is affected by the atmosphere, thus the image needs to be corrected. Due to the spatial and temporal variability of atmospheric conditions, correction by using synchronous atmospheric parameters can effectively improve the remote sensing image quality. For this reason, a small light spaceborne instrument, the atmospheric synchronous correction device (airborne prototype), is developed by AIOFM of CAS(Anhui Institute of Optics and Fine Mechanics of Chinese Academy of Sciences). With this instrument, of which the detection mode is timing synchronization and spatial coverage, the atmospheric parameters consistent with the images to be corrected in time and space can be obtained, and then the correction is achieved by radiative transfer model. To verify the technical process and treatment effect of spaceborne atmospheric correction system, the first airborne experiment is designed and completed. The experiment is implemented by the "satellite-airborne-ground" synchronous measuring method. A high resolution(0.4 m) camera and the atmospheric correction device are equipped on the aircraft, which photograph the ground with the satellite observation over the top simultaneously. And aerosol optical depth (AOD) and columnar water vapor (CWV) in the imagery area are also acquired, which are used for the atmospheric correction for satellite and aerial images. Experimental results show that using the AOD and CWV of imagery area retrieved by the data obtained by the device to correct aviation and satellite images, can improve image definition and contrast by more than 30%, and increase MTF by more than 1 time, which means atmospheric correction for satellite images by using the data of spaceborne atmospheric synchronous correction device is accurate and effective.

  14. Atmospheric Line of Site Experiment (ALOSE) Final Campaign Summary

    SciTech Connect

    Smith, W.; Green, S.; Howard, M.; Yesalusky, M.; Modlin, N.

    2016-03-01

    The Atmospheric Line of Site Experiment (ALOSE) was a project to produce best-estimate atmospheric state measurements at the: 1. DOE Atmospheric Radiation Measurement (ARM) Clouds and Radiation Test-bed (CART) site located in Lamont, Oklahoma (11–14 December 2012) 2. Poker Flat Alaska Research Range (PFRR) located in Poker Flat, Alaska (19–26 February 2013) 3. DOE ARM CART site located in Lamont, Oklahoma (24–28 April 2013) 4. DOE ARM CART site located in Lamont, Oklahoma (9–15 July 2013) 5. DOE ARM Tropical Western Pacific (TWP) site located in Darwin, Australia (27 September–3 October 2013).

  15. A Shuttle Upper Atmosphere Mass Spectrometer /SUMS/ experiment

    NASA Technical Reports Server (NTRS)

    Blanchard, R. C.; Duckett, R. J.; Hinson, E. W.

    1982-01-01

    A magnetic mass spectrometer is currently being adapted to the Space Shuttle Orbiter to provide repeated high altitude atmosphere data to support in situ rarefied flow aerodynamics research, i.e., in the high velocity, low density flight regime. The experiment, called Shuttle Upper Atmosphere Mass Spectrometer (SUMS), is the first attempt to design mass spectrometer equipment for flight vehicle aerodynamic data extraction. The SUMS experiment will provide total freestream atmospheric quantitites, principally total mass density, above altitudes at which conventional pressure measurements are valid. Experiment concepts, the expected flight profile, tradeoffs in the design of the total system and flight data reduction plans are discussed. Development plans are based upon a SUMS first flight after the Orbiter initial development flights.

  16. Lower Atmospheric Boundary Layer Experiment (LABLE) Final Campaign Report

    SciTech Connect

    Klein, P; Bonin, TA; Newman, JF; Turner, DD; Chilson, P; Blumberg, WG; Mishra, S; Wainwright, CE; Carney, M; Jacobsen, EP; Wharton, S

    2015-11-01

    The Lower Atmospheric Boundary Layer Experiment (LABLE) included two measurement campaigns conducted at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site in Oklahoma during 2012 and 2013. LABLE was designed as a multi-phase, low-cost collaboration among the University of Oklahoma, the National Severe Storms Laboratory, Lawrence Livermore National Laboratory, and the ARM program. A unique aspect was the role of graduate students in LABLE. They served as principal investigators and took the lead in designing and conducting experiments using different sampling strategies to best resolve boundary-layer phenomena.

  17. An Atmospheric Science Observing System Simulation Experiment (OSSE) Environment

    NASA Technical Reports Server (NTRS)

    Lee, Meemong; Weidner, Richard; Qu, Zheng; Bowman, Kevin; Eldering, Annmarie

    2010-01-01

    An atmospheric sounding mission starts with a wide range of concept designs involving measurement technologies, observing platforms, and observation scenarios. Observing system simulation experiment (OSSE) is a technical approach to evaluate the relative merits of mission and instrument concepts. At Jet Propulsion Laboratory (JPL), the OSSE team has developed an OSSE environment that allows atmospheric scientists to systematically explore a wide range of mission and instrument concepts and formulate a science traceability matrix with a quantitative science impact analysis. The OSSE environment virtually creates a multi-platform atmospheric sounding testbed (MAST) by integrating atmospheric phenomena models, forward modeling methods, and inverse modeling methods. The MAST performs OSSEs in four loosely coupled processes, observation scenario exploration, measurement quality exploration, measurement quality evaluation, and science impact analysis.

  18. Characterization of Settled Atmospheric Dust by the DART Experiment

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Jenkins, Phillip P.; Baraona, Cosmo

    1999-01-01

    The DART ("Dust Accumulation and Removal Test") package is an experiment which will fly as part of the MIP experiment on the Mars-2001 Surveyor Lander. Dust deposition could be a significant problem for photovoltaic array operation for long duration emissions on the surface of Mars. Measurements made by Pathfinder showed 0.3% loss of solar array performance per day due to dust obscuration. The DART experiment is designed to quantify dust deposition from the Mars atmosphere, measure the properties of settled dust, measure the effect of dust deposition on the array performance, and test several methods of mitigating the effect of settled dust on a solar array. Although the purpose of DART (along with its sister experiment, MATE) is to gather information critical to the design of future power systems on the surface of Mars, the dust characterization instrumentation on DART will also provide significant scientific data on the properties of settled atmospheric dust.

  19. Nuclear effects in atmospheric and accelerator neutrino experiments

    SciTech Connect

    Chauhan, S.; Athar, M. Sajjad; Singh, S. K.

    2010-11-24

    We have studied the nuclear medium effects in the neutrino (antineutrino) induced interactions in nuclei at intermediate energy region. We have applied this study to calculate the event rates for atmospheric and accelerator neutrino experiments. The study of the nuclear effects has been done for the quasielastic lepton production and the charged current incoherent and coherent pion production processes.

  20. Feasibility study: Atmospheric general circulation experiment, volume 2

    NASA Technical Reports Server (NTRS)

    Homsey, R. J. (Editor)

    1981-01-01

    The feasibility analysis of the atmospheric general circulation experiment (AGCE) are documented. The analysis performed in each technical area, the rationale and substantiation for the design approaches selected for the hardware, and the design details for the baseline AGCE are presented.

  1. The Atmospheric Lifetime Experiment and the Global Atmospheric Gas Experiment (ALE/GAGE)

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    The ALE/GAGE project was designed to determine the global atmospheric lifetimes of the chlorofluorocarbons CCl3F and CCl2F2 (F-11 and F-12), which had been identified as the main gases that cause stratospheric ozone depletion. The experimental procedures also provided the concentrations of CH3CCl3, CCl4 and N2O. The extended role of the project was to evaluate the mass balances of these gases as well. Methylchloroform (CH3CCl3) serves as a tracer of average atmospheric OH concentrations and hence the oxidizing capacity of the atmosphere. Nitrous oxide (N2O) is a potent greenhouse gas and can also deplete the ozone layer. Measurements of these gases were taken with optimized instruments in the field at a frequency of about 1 sample/hr. Toward the end of the present project methane measurements were added to the program. The final report deals with the research of the Oregon Graduate Institute (OGI) as part of the ALE/GAGE program between 4/1/1988 and 1/31/1991. The report defines the scope of the OGI project, the approach, and the results.

  2. Science support for the atmospheric trace molecule spectroscopy (ATMOS) experiment

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.

    1982-01-01

    The experiment is a satellite solar occultation interferometer spectrometer experiment under development for flight on Spacelab 3. Launch is expected in March 1985. ATMOS will provide high spectral resolution (0.02/cm) and high spatial resolution (2 km from Shuttle altitude) data over the spectral range from 2 micrometers to 16 micrometers. This region of the spectrum is rich in absorption features of major and minor trace gases which are critical to the understanding of the chemistry and physics of the Earth's upper atmosphere. The broad objectives of the ATMOS experiment are to: identify and measure, on a global scale, the volume mixing ratios of known and newly discovered molecular species; determine vertical profiles for these species; and provide spectral data on the atmosphere for use in optimizing the design of future instruments to monitor specific gases.

  3. Atmospheric measurements on Mars - The Viking meteorology experiment

    NASA Technical Reports Server (NTRS)

    Chamberlain, T. E.; Cole, H. L.; Dutton, R. G.; Greene, G. C.; Tillman, J. E.

    1976-01-01

    The Viking meteorology experiment is one of nine experiments to be carried out on the surface of Mars by each of two Viking Landers positioned at different latitudes and longitudes in the Northern Hemisphere. The meteorology experiment will measure pressure, temperature, wind speed, and wind direction at 1.5-hr intervals throughout the Martian day. The duration of each measurement period, the interval between data samples for a measurement period, and the time at which the measurement period is started will be varied throughout the mission. The scientific investigation and the sensors and electronics used for making the atmospheric measurement are discussed.

  4. Atmospheric measurements on Mars - The Viking meteorology experiment

    NASA Technical Reports Server (NTRS)

    Chamberlain, T. E.; Cole, H. L.; Dutton, R. G.; Greene, G. C.; Tillman, J. E.

    1976-01-01

    The Viking meteorology experiment is one of nine experiments to be carried out on the surface of Mars by each of two Viking Landers positioned at different latitudes and longitudes in the Northern Hemisphere. The meteorology experiment will measure pressure, temperature, wind speed, and wind direction at 1.5-hr intervals throughout the Martian day. The duration of each measurement period, the interval between data samples for a measurement period, and the time at which the measurement period is started will be varied throughout the mission. The scientific investigation and the sensors and electronics used for making the atmospheric measurement are discussed.

  5. Molecular line parameters for the atmospheric trace molecule spectroscopy experiment

    NASA Technical Reports Server (NTRS)

    Brown, L. R.; Farmer, C. B.; Toth, R. A.; Rinsland, Curtis P.

    1987-01-01

    During its first mission in 1985 onboard Spacelab 3, the ATMOS (atmospheric trace molecule spectroscopy) instrument, a high speed Fourier transform spectrometer, produced a large number of high resolution infrared solar absorption spectra recorded in the occultation mode. The analysis and interpretation of these data in terms of composition, chemistry, and dynamics of the earth's upper atmosphere required good knowledge of the molecular line parameters for those species giving rise to the absorptions in the atmospheric spectra. This paper describes the spectroscopic line parameter database compiled for the ATMOS experiment and referenced in other papers describing ATMOS results. With over 400,000 entries, the linelist catalogs parameters of 46 minor and trace species in the 1-10,000/cm region.

  6. Atmospheric neutrino results from Super-Kamiokande experiment

    NASA Astrophysics Data System (ADS)

    Obayashi, Yoshihisa; Super-KAMIOKANDE Collaboration

    2000-12-01

    Super-Kamiokande has been observing atmospheric neutrinos since April 1, 1996. The observation livetime is now 990 days, corresponding to an exposure of 61 kt-yr. Observed flavor, energy and direction distributions of are inconsistent with atmospheric neutrino flux assuming no neutrino oscillation; they are, however, consistent with νμ to ντ oscillation. The allowed νμ to ντ oscillation parameter space is 2×10-3<Δm2<5×10-3eV2 and sin2 2θ>0.88, at 90% confidence level. This result agrees well with other recent underground atmospheric neutrino experiments. The data have also been analyzed for νμ to νsterile oscillation and νe-νμ-ντ 3-flavor oscillation. Both analyses favor νμ to ντ oscillation.

  7. Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE)

    NASA Technical Reports Server (NTRS)

    Imhof, W. L.; Voss, H. D.; Mobilia, J.; Datlowe, D. W.; Chinn, V. L.; Hilsenrath, M.; Vondrak, R. R.

    1996-01-01

    This report summarizes the activities sponsored by the Office of Naval Research for the Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE). The MAXIE instrument was developed as a joint activity of Lockheed, The Aerospace Corporation, and the University of Bergen, Norway. Lockheed was responsible for the overall management of the program, interfacing with the appropriate government agencies, the overall electrical and mechanical design, flight software, environmental testing, spacecraft integration activities, on orbit checkout, and data processing activities. The Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE), the ONR 401 experiment, is the first in a new class of satellite-borne remote sensing instruments. The primary innovation is the ability to obtain rapid, sequential, images with high sensitivity of the earth's X ray aurora from a low altitude polar orbiting satellite. These images can be used to identify dynamic temporal variations in the three-dimensional (energy and position) distribution of electron precipitation into the atmosphere. MAXIE was launched on the TIROS NOAA-13 satellite on 9 August 1993. The experiment performed well during its turn-on sequence; however, the spacecraft bus failed on 21 August 1993. New spacebased technologies successfully used in MAXIE were mixed-mode ASIC microcircuits, a zero torque scanning system with associated viscoelastic damping, a paraffin stow release mechanism, a parallel integrating PHA processor, a low noise Si(Li) sensor telescope, and an advanced thermal cooling system. MAXIE's on orbit operation, control of penetrating particle backgrounds, and scientific data indicated good overall performance.

  8. Velocity aberration and atmospheric refraction in satellite laser communication experiments.

    PubMed

    Nugent, L J; Condon, R J

    1966-11-01

    The effects of satellite velocity aberration and atmospheric refraction on the direction of propagation of lagser radiation reflected from a satellite back to an observer on the earth are examined. A velocity aberration analysis for the two-dimensional case where the satellite passes directly overhead at velocity v is presented to first order in v/c in order to illustrate the method. The equations for the more general threedimensional case are then given to first order in v/c, and it is indicated that higher order treatments are normally unnecessary in typical experimental considerations. Following this, a simple approximate equation giving the atmospheric refraction to an accuracy of a few microradians is developed; it is indicated that greater accuracy is not important because of laser pointing limitations imposed by atmospheric scattering and turbulence. The atmospheric refraction equation depends only on the apparent zenith angle of the satellite reflector relative to the earth-based laser, on the satelli-te altitude, and on the index of refraction of the laser radiation in the atmosphere at the earth's surface. Both of these developments should be useful in the design and interpretation of satellite laser-communication experiments.

  9. The atmospheric lifetime experiment. I - Introduction, instrumentation, and overview

    NASA Astrophysics Data System (ADS)

    Prinn, R. G.; Simmonds, P. G.; Rasmussen, R. A.; Crawford, A. J.; Rosen, R. D.; Alyea, F. N.; Cardelino, C. A.; Cunnold, D. M.; Fraser, P. J.; Lovelock, J. E.

    1983-10-01

    The Atmospheric Lifetime Experiment is designed to determine accurately the atmospheric concentrations of the four halocarbons CFCl3, CF2Cl2, CCl4, and CH3CCl3, and also of N2O with emphasis on measurement of their long-term trends in the atmosphere. Comparison of these concentrations and trends for the four halocarbons with estimates of their industrial emission rates then enables calculations of their global circulation rates and globally averaged atmospheric lifetimes. The experiment utilizes automated dual-column electron-capture gas chromatographs which sample the background air about 4 times daily at the following globally distributed sites: Adrigole, Ireland, Cape Meares, Oregon; Ragged Point, Barbados; Point Matatula, American Samoa, and Cape Grim, Tasmania. The climatology of these 'clean air' sites and their ability to describe the global air mass are reviewed. The instrumentation and methods for data acquisition and processing are then described. An overview of the data obtained and the trends derived during the 3-year period from July 1978 through June 1981 for each of the five species being measured is presented.

  10. The atmospheric lifetime experiment. I - Introduction, instrumentation, and overview

    NASA Technical Reports Server (NTRS)

    Prinn, R. G.; Simmonds, P. G.; Rasmussen, R. A.; Crawford, A. J.; Rosen, R. D.; Alyea, F. N.; Cardelino, C. A.; Cunnold, D. M.; Fraser, P. J.; Lovelock, J. E.

    1983-01-01

    The Atmospheric Lifetime Experiment is designed to determine accurately the atmospheric concentrations of the four halocarbons CFCl3, CF2Cl2, CCl4, and CH3CCl3, and also of N2O with emphasis on measurement of their long-term trends in the atmosphere. Comparison of these concentrations and trends for the four halocarbons with estimates of their industrial emission rates then enables calculations of their global circulation rates and globally averaged atmospheric lifetimes. The experiment utilizes automated dual-column electron-capture gas chromatographs which sample the background air about 4 times daily at the following globally distributed sites: Adrigole, Ireland, Cape Meares, Oregon; Ragged Point, Barbados; Point Matatula, American Samoa, and Cape Grim, Tasmania. The climatology of these 'clean air' sites and their ability to describe the global air mass are reviewed. The instrumentation and methods for data acquisition and processing are then described. An overview of the data obtained and the trends derived during the 3-year period from July 1978 through June 1981 for each of the five species being measured is presented.

  11. Spectroscopic, Kinetic, and Dynamic Experiments on Atmospheric Species.

    DTIC Science & Technology

    1985-03-21

    0077 PHYSICAL SCIENCES RESEARCH PAPERS , NO. 668 P D-A 162 691 Spectroscopic, Kinetic, and Dynamic Experiments on Atmospheric Species S. M. MILLER J. I...we observed, in a very limited data base , values similar to those predicted by the theory of Billingsley4 over the range 4 ! v’ :- 12. This result is...the identities of several others. Further investigations will be aided by an improved data base under conditions similar to those in Figure 9, with

  12. Atmospheric Emissions Photometric Imaging Experiment For Spacelab 1

    NASA Astrophysics Data System (ADS)

    Sandie, William G.; Mende, Stephen B.; Swenson, Gary R.; Polites, Michael E.

    1983-12-01

    The atmospheric emissions photometric imaging (AEPI) experiment to be flown on Spacelab 1 is designed to study faint natural and artificial atmospheric emission phenomena. Atmospheric emissions in the spectral region 2000 A to 7500 A from two optical channels, wide angle and telephoto, are detected by an image-enhanced low-light-level TV system. A third, telephoto, optical channel images onto the photocathode of a microchannel plate photomultiplier tube having 100 discrete anodes. Photons are counted for each discrete anode, providing a direct measure of the luminosity of an object viewed by the TV telephoto lens, albeit with low spatial resolution. Detector pointing in the range +/-40°x+/-80°exclusive of restrictions due to the proximity of other experiments is provided by a two-axis gimbal made from a surplus Apollo telescope mount (MAST). The pointing stability is 1 arc min with respect to the spacecraft coordinate system for an exposure of one s, and the tracking capability is 3.5 deg - s-1 with a stability of 1 arc min. The detector and pointing system are located on the Spacelab pallet and are controlled by stored programs resident in the dedicated experiment processor located in the Spacelab module.

  13. ARESE (ARM Enhanced Shortwave Experiment) Science Plan [Atmospheric Radiation Program

    SciTech Connect

    Valero, F.P.J.; Schwartz, S.E.; Cess, R.D.; Ramanathan, V.; Collins, W.D.; Minnis, P.; Ackerman, T.P.; Vitko, J.; Tooman, T.P.

    1995-09-27

    Several recent studies have indicated that cloudy atmospheres may absorb significantly more solar radiation than currently predicted by models. The magnitude of this excess atmospheric absorption, is about 50% more than currently predicted and would have major impact on our understanding of atmospheric heating. Incorporation of this excess heating into existing general circulation models also appears to ameliorate some significant shortcomings of these models, most notably a tendency to overpredict the amount of radiant energy going into the oceans and to underpredict the tropopause temperature. However, some earlier studies do not show this excess absorption and an underlying physical mechanism that would give rise to such absorption has yet to be defined. Given the importance of this issue, the Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) program is sponsoring the ARM Enhanced Shortwave Experiment (ARESE) to study the absorption of solar radiation by clear and cloudy atmospheres. The experimental results will be compared with model calculations. Measurements will be conducted using three aircraft platforms (ARM-UAV Egrett, NASA ER-2, and an instrumented Twin Otter), as well as satellites and the ARM central and extended facilities in North Central Oklahoma. The project will occur over a four week period beginning in late September, 1995. Spectral broadband, partial bandpass, and narrow bandpass (10nm) solar radiative fluxes will be measured at different altitudes and at the surface with the objective to determine directly the magnitude and spectral characteristics of the absorption of shortwave radiation by the atmosphere (clear and cloudy). Narrow spectral channels selected to coincide with absorption by liquid water and ice will help in identifying the process of absorption of radiation. Additionally, information such as water vapor profiles, aerosol optical depths, cloud structure and ozone profiles, needed to use as input in radiative

  14. Atmospheric emissions photometric imaging experiment /AEPT/ for Spacelab 1

    NASA Astrophysics Data System (ADS)

    Sandie, W. G.; Mende, S. B.; Swenson, G. R.; Polites, M. E.

    1981-04-01

    The atmospheric emissions photometric imaging experiment (AEPI) to be flown on Spacelab 1 is designed to study faint natural and artificial atmospheric emission phenomena. Optical emissions are imaged in the region 2150 A to 7320 A using a television system consisting of two optical channels, one wide-angle and one telephoto. The detection system is an image-enhanced SEC vidicon. A third optical channel images onto the photocathode of a microchannel plate photomultiplier tube that has 100 discrete anodes. Photons are counted for each discrete anode, providing a direct measure of the luminosity of an object viewed by the TV telephoto lens, albeit with low spatial resolution. The AEPI detector is mounted on a two-axis gimbal comprised of a Modified Apollo Telescope Mount Star Tracker (MAST), which provides experiment pointing over a 40-deg x 80-deg range, exclusive of restrictions due to the proximity of other experiments. The pointing stability is 1 arcmin with respect to the spacecraft coordinate system for an exposure of 1 second. The tracking capability is 3.5 deg/s with a stability of 1 arcmin. The detector and pointing system are located on the Spacelab pallet. The experiment is controlled by stored programs resident in the Dedicated Experiment Processor located in the Spacelab module.

  15. Atmospheric Climate Model Experiments Performed at Multiple Horizontal Resolutions

    SciTech Connect

    Phillips, T; Bala, G; Gleckler, P; Lobell, D; Mirin, A; Maxwell, R; Rotman, D

    2007-12-21

    This report documents salient features of version 3.3 of the Community Atmosphere Model (CAM3.3) and of three climate simulations in which the resolution of its latitude-longitude grid was systematically increased. For all these simulations of global atmospheric climate during the period 1980-1999, observed monthly ocean surface temperatures and sea ice extents were prescribed according to standard Atmospheric Model Intercomparison Project (AMIP) values. These CAM3.3 resolution experiments served as control runs for subsequent simulations of the climatic effects of agricultural irrigation, the focus of a Laboratory Directed Research and Development (LDRD) project. The CAM3.3 model was able to replicate basic features of the historical climate, although biases in a number of atmospheric variables were evident. Increasing horizontal resolution also generally failed to ameliorate the large-scale errors in most of the climate variables that could be compared with observations. A notable exception was the simulation of precipitation, which incrementally improved with increasing resolution, especially in regions where orography plays a central role in determining the local hydroclimate.

  16. Land-Atmosphere Feedback Experiment (LAFE) Science Plan

    SciTech Connect

    Wulfmeyer, Volker; Turner, David

    2016-07-01

    The Land-Atmosphere Feedback Experiment (LAFE; pronounced “la-fey”) deploys several state-of-the-art scanning lidar and remote sensing systems to the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Southern Great Plains (SGP) site. These instruments will augment the ARM instrument suite in order to collect a data set for studying feedback processes between the land surface and the atmosphere. The novel synergy of remote-sensing systems will be applied for simultaneous measurements of land-surface fluxes and horizontal and vertical transport processes in the atmospheric convective boundary layer (CBL). The impact of spatial inhomogeneities of the soil-vegetation continuum on land-surface-atmosphere (LSA) feedback will be studied using the scanning capability of the instrumentation. The time period of the observations is August 2017, because large differences in surface fluxes between different fields and bare soil can be observed, e.g., pastures versus fields where the wheat has already been harvested. The remote sensing system synergy will consist of three components: 1) The SGP water vapor and temperature Raman lidar (SRL), the SGP Doppler lidar (SDL), and the National Center for Atmospheric Research (NCAR) water vapor differential absorption lidar (DIAL) (NDIAL) mainly in vertical staring modes to measure mean profiles and gradients of moisture, temperature, and horizontal wind. They will also measure profiles of higher-order turbulent moments in the water vapor and wind fields and profiles of the latent heat flux. 2) A novel scanning lidar system synergy consisting of the National Oceanic and Atmospheric Administration (NOAA) High-Resolution Doppler lidar (HRDL), the University of Hohenheim (UHOH) water-vapor differential absorption lidar (UDIAL), and the UHOH temperature Raman lidar (URL). These systems will perform coordinated range-height indicator (RHI) scans from just above the canopy level to the

  17. Atmospheric Results from the MGS Horizon Science Experiment

    NASA Technical Reports Server (NTRS)

    Martin, T. Z.; Murphy, J. R.; Hollingsworth, J. L.

    1999-01-01

    The Horizon Science Experiment (HORSE) utilizes the Mars Horizon Sensor Assembly (MHSA) on the Mars Global Surveyor (MGS) orbiter to measure 15-micron band thermal emission from the Martian atmosphere. During the first two phases of aerobraking, from September 1997 to May 1998, and from September 1998 to March 1999, one of the four MGS quadrants was pointed well onto the planet consistently during the near-periapsis aerobraking passes, allowing the device to obtain data on the latitudinal variation of middle atmospheric temperature (0.2 - 2.0 mbar). Of particular interest during the first phase (L(sub s) = 182 - 300 deg) were the effects of a prominent dust storm at L(sub s) =224 deg, and wavelike behavior in the strong temperature gradient near the north polar cap. Additional information is contained in the original extended abstract.

  18. Global phosgene observations from the Atmospheric Chemistry Experiment (ACE) mission

    NASA Astrophysics Data System (ADS)

    Fu, Dejian; Boone, Chris D.; Bernath, Peter F.; Walker, Kaley A.; Nassar, Ray; Manney, Gloria L.; McLeod, Sean D.

    2007-09-01

    The first study of the global distribution of atmospheric phosgene (COCl2) has been performed using solar occultation measurements from the Atmospheric Chemistry Experiment (ACE) satellite mission. A total of 5614 measured profiles spanning the period February 2004 through May 2006 were used in the study. The phosgene concentrations display a zonally symmetric pattern with the maximum concentration located approximately over the equator at about 25 km in altitude and the concentration decreases towards the poles. A layer of enhanced concentration of phosgene spans the lower stratosphere over all latitudes, with volume mixing ratios of 20-60 pptv. The ACE observations show lower phosgene concentrations in the stratosphere than were obtained from previous observations in the 1980s and 1990s. This has been attributed to a significant decrease in its source species, particularly two major sources CH3CCl3 and CCl4, since the introduction of restrictions required by the Montreal Protocol and its amendments.

  19. Atmospheric science experiments applicable to Space Shuttle Spacelab missions

    NASA Technical Reports Server (NTRS)

    Wilson, G. S.; Christian, H. J., Jr.; Fichtl, G. H.; Vaughan, W. W.; Goodman, S. J.; Robertson, F. R.

    1984-01-01

    The present lack of a lower atmosphere research satellite program for the 1980s has prompted consideration of the Space Shuttle/Spacelab system as a means of flying sensor complements geared toward specific research problems, as well as continued instrument development. Three specific examples of possible science questions related to precipitation are discussed: (1) spatial structure of mesoscale cloud and precipitation systems, (2) lightning and storm development, and (3) cyclone intensification over oceanic regions. Examples of space sensors availab le to provide measurements needed in addressing these questions are also presented. Distinctive aspects of low-earth orbit experiments would be high resolution, multispectral sensing of atmospheric phenomena by complements of instruments, and more efficient sensor development through reflights of specific hardware packages.

  20. First Global Observations of Atmospheric COCIF from the Atmospheric Chemistry Experiment Mission

    NASA Technical Reports Server (NTRS)

    Fu, Dejian; Boone, Chris D.; Bernath, Peter F.; Weisenstein, Debra K.; Rinsland, Curtis P.; Manney, Gloria L.; Walker, Kaley A.

    2010-01-01

    Carbonyl chlorofluoride (COCIF) is an important reservoir of chlorine and fluorine in the Earth's atmosphere. Satellite-based remote sensing measurements of COCIF, obtained by the Atmospheric Chemistry Experiment (ACE) for a time period spanning February 2004 through April 2007, have been used in a global distribution study. There is a strong source region for COCIF in the tropical stratosphere near 27 km. A layer of enhanced COCIF spans the low- to mid-stratosphere over all latitudes, with volume mixing ratios of 40-100 parts per trillion by volume, largest in the tropics and decreasing toward the poles. The COCIF volume mixing ratio profiles are nearly zonally symmetric, but they exhibit a small hemispheric asymmetry that likely arises from a hemispheric asymmetry in the parent molecule CCl3 F. Comparisons are made with a set of in situ stratospheric measurements from the mid-1980s and with predictions from a 2-D model.

  1. Appendix C: First Global Observations of Atmospheric COClF from the Atmospheric Chemistry Experiment Mission

    NASA Technical Reports Server (NTRS)

    Fu, Djian; Boone, Chris D.; Bernath, Peter F.; Walker, Kaley A.; Rinsland, Curtis P.; Weisenstein, Debra K.; Manney, Gloria L.

    2009-01-01

    Carbonyl chlorofluoride (COCIF) is an important reservoir of chlorine and Fluorine in the Earth's atmosphere. Satellite-based remote sensing measurements of COCIF, obtained by Received in revised form the Atmospheric Chemistry Experiment (ACE) for a time period spanning February 2004 through April 2007, have been used in a global distribution study. There is a strong Accepted 18 February 2009 source region for COCIF in the tropical stratosphere near 27 km. A layer of enhanced COCIF spans the low- to mid-stratosphere over all latitudes, with volume mixing ratios of 40-100 parts Per trillion by volume, largest in the tropics and decreasing toward the poles. The COCIF volume mixing ratio profiles are nearly zonally symmetric, but they exhibit a small hemispheric asymmetry that likely arises from a hemispheric asymmetry in the parent molecule CCl3F. Comparisons are made with a set of in situ stratospheric measurements from the mid-1980s and with predictions from a 2-D model.

  2. Experiments of reconstructing discrete atmospheric dynamic models from data (I)

    NASA Astrophysics Data System (ADS)

    Lin, Zhenshan; Zhu, Yanyu; Deng, Ziwang

    1995-03-01

    In this paper, we give some experimental results of our study in reconstructing discrete atmospheric dynamic models from data. After a great deal of numerical experiments, we found that the logistic map, x n + 1 = 1- μx {2/n}, could be used in monthly mean temperature prediction when it was approaching the chaotic region, and its predictive results were in reverse states to the practical data. This means that the nonlinear developing behavior of the monthly mean temperature system is bifurcating back into the critical chaotic states from the chaotic ones.

  3. Land-atmosphere coupling in EURO-CORDEX evaluation experiments

    NASA Astrophysics Data System (ADS)

    Knist, Sebastian; Goergen, Klaus; Buonomo, Erasmo; Christensen, Ole Bøssing; Colette, Augustin; Cardoso, Rita M.; Fealy, Rowan; Fernández, Jesús; García-Díez, Markel; Jacob, Daniela; Kartsios, Stergios; Katragkou, Eleni; Keuler, Klaus; Mayer, Stephanie; van Meijgaard, Erik; Nikulin, Grigory; Soares, Pedro M. M.; Sobolowski, Stefan; Szepszo, Gabriella; Teichmann, Claas; Vautard, Robert; Warrach-Sagi, Kirsten; Wulfmeyer, Volker; Simmer, Clemens

    2017-01-01

    Interactions between the land surface and the atmosphere play a fundamental role in the weather and climate system. Here we present a comparison of summertime land-atmosphere coupling strength found in a subset of the ERA-Interim-driven European domain Coordinated Regional Climate Downscaling Experiment (EURO-CORDEX) model ensemble (1989-2008). Most of the regional climate models (RCMs) reproduce the overall soil moisture interannual variability, spatial patterns, and annual cycles of surface exchange fluxes for the different European climate zones suggested by the observational Global Land Evaporation Amsterdam Model (GLEAM) and FLUXNET data sets. However, some RCMs differ substantially from FLUXNET observations for some regions. The coupling strength is quantified by the correlation between the surface sensible and the latent heat flux, and by the correlation between the latent heat flux and 2 m temperature. The first correlation is compared to its estimate from the few available long-term European high-quality FLUXNET observations, and the latter to results from gridded GLEAM data. The RCM simulations agree with both observational datasets in the large-scale pattern characterized by strong coupling in southern Europe and weak coupling in northern Europe. However, in the transition zone from strong to weak coupling covering large parts of central Europe many of the RCMs tend to overestimate the coupling strength in comparison to both FLUXNET and GLEAM. The RCM ensemble spread is caused primarily by the different land surface models applied, and by the model-specific weather conditions resulting from different atmospheric parameterizations.

  4. Balloon UV experiments for astronomical and atmospheric observations

    NASA Astrophysics Data System (ADS)

    A. G., Sreejith; Mathew, Joice; Sarpotdar, Mayuresh; K., Nirmal; Ambily, S.; Prakash, Ajin; Safonova, Margarita; Murthy, Jayant

    2016-08-01

    The ultraviolet (UV) window has been largely unexplored through balloons for astronomy. We discuss here the development of a compact near-UV spectrograph with fiber optics input for balloon flights. It is a modified Czerny-Turner system built using off-the-shelf components. The system is portable and scalable to different telescopes. The use of reflecting optics reduces the transmission loss in the UV. It employs an image-intensified CMOS sensor, operating in photon counting mode, as the detector of choice. A lightweight pointing system developed for stable pointing to observe astronomical sources is also discussed, together with the methods to improve its accuracy, e.g. using the in-house build star sensor and others. Our primary scientific objectives include the observation of bright Solar System objects such as visible to eye comets, Moon and planets. Studies of planets can give us valuable information about the planetary aurorae, helping to model and compare atmospheres of other planets and the Earth. The other major objective is to look at the diffuse UV atmospheric emission features (airglow lines), and at column densities of trace gases. This UV window includes several lines important to atmospheric chemistry, e.g. SO2, O3, HCHO, BrO. The spectrograph enables simultaneous measurement of various trace gases, as well as provides better accuracy at higher altitudes compared to electromechanical trace gas measurement sondes. These lines contaminate most astronomical observations but are poorly characterized. Other objectives may include sprites in the atmosphere and meteor ashes from high altitude burn-outs. Our recent experiments and observations with high-altitude balloons are discussed.

  5. Preliminary design for Arctic atmospheric radiative transfer experiments

    NASA Technical Reports Server (NTRS)

    Zak, B. D.; Church, H. W.; Stamnes, K.; Shaw, G.; Filyushkin, V.; Jin, Z.; Ellingson, R. G.; Tsay, S. C.

    1995-01-01

    If current plans are realized, within the next few years, an extraordinary set of coordinated research efforts focusing on energy flows in the Arctic will be implemented. All are motivated by the prospect of global climate change. SHEBA (Surface Energy Budget of the Arctic Ocean), led by the National Science Foundation (NSF) and the Office of Naval Research (ONR), involves instrumenting an ice camp in the perennial Arctic ice pack, and taking data for 12-18 months. The ARM (Atmospheric Radiation Measurement) North Slope of Alaska and Adjacent Arctic Ocean (NSA/AAO) Cloud and Radiation Testbed (CART) focuses on atmospheric radiative transport, especially in the presence of clouds. The NSA/AAO CART involves instrumenting a sizeable area on the North Slope of Alaska and adjacent waters in the vicinity of Barrow, and acquiring data over a period of about 10 years. FIRE (First ISCCP (International Satellite Cloud Climatology Program) Regional Experiment) Phase 3 is a program led by the National Aeronautics and Space Administration (NASA) which focuses on Arctic clouds, and which is coordinated with SHEBA and ARM. FIRE has historically emphasized data from airborne and satellite platforms. All three program anticipate initiating Arctic data acquisition during spring, 1997. In light of his historic opportunity, the authors discuss a strawman atmospheric radiative transfer experimental plan that identifies which features of the radiative transport models they think should be tested, what experimental data are required for each type of test, the platforms and instrumentation necessary to acquire those data, and in general terms, how the experiments could be conducted. Aspects of the plan are applicable to all three programs.

  6. The Third Tibetan Plateau Atmospheric Scientific Experiment for Understanding the Earth-Atmosphere Coupled System

    NASA Astrophysics Data System (ADS)

    Zhao, P.; Xu, X.; Chen, F.; Guo, X.; Zheng, X.; Liu, L. P.; Hong, Y.; Li, Y.; La, Z.; Peng, H.; Zhong, L. Z.; Ma, Y.; Tang, S. H.; Liu, Y.; Liu, H.; Li, Y. H.; Zhang, Q.; Hu, Z.; Sun, J. H.; Zhang, S.; Dong, L.; Zhang, H.; Zhao, Y.; Yan, X.; Xiao, A.; Wan, W.; Zhou, X.

    2016-12-01

    The Third Tibetan Plateau atmospheric scientific experiment (TIPEX-III) was initiated jointly by the China Meteorological Administration, the National Natural Scientific Foundation, and the Chinese Academy of Sciences. This paper presents the background, scientific objectives, and overall experimental design of TIPEX-III. It was designed to conduct an integrated observation of the earth-atmosphere coupled system over the Tibetan Plateau (TP) from land surface, planetary boundary layer (PBL), troposphere, and stratosphere for eight to ten years by coordinating ground- and air-based measurement facilities for understanding spatial heterogeneities of complex land-air interactions, cloud-precipitation physical processes, and interactions between troposphere and stratosphere. TIPEX-III originally began in 2014, and is ongoing. It established multiscale land-surface and PBL observation networks over the TP and a tropospheric meteorological radiosonde network over the western TP, and executed an integrated observation mission for cloud-precipitation physical features using ground-based radar systems and aircraft campaigns and an observation task for atmospheric ozone, aerosol, and water vapor. The archive, management, and share policy of the observation data are also introduced herein. Some TIPEX-III data have been preliminarily applied to analyze the features of surface sensible and latent heat fluxes, cloud-precipitation physical processes, and atmospheric water vapor and ozone over the TP, and to improve the local precipitation forecast. Furthermore, TIPEX-III intends to promote greater scientific and technological cooperation with international research communities and broader organizations. Scientists working internationally are invited to participate in the field campaigns and to use the TIPEX-III data for their own research.

  7. The field experiments on the HTO washout from the atmosphere

    SciTech Connect

    Golubev, A.V.; Mavrin, S.V.; Golubeva, V.N.; Stengach, A.V.; Balashov, Y.S.; Kovalenko, V.P.; Solomatin, I.I.

    2015-03-15

    HTO (tritiated water) wash-out from the atmosphere is one of the key processes governing the HTO transport from the atmosphere into soil and plants. Experimental studies of the HTO interaction with water drops were carried out both in laboratories and in the field. In the course of experiments, the following rain characteristics were recorded: rain intensity, size distribution of drops, and falling velocities and their dependence on drop diameter. A laser optical device was designed and used to measure the distribution of the drop radius and velocities during the period of experiment. The tritium source was placed at a height of 30 m. Rainwater samples were collected in plastic bottles and their HTO activity was determined by liquid scintillation techniques. The data obtained for the experimental values of the scavenging rate are within the range from 4.12*10{sup -5} to 1.57*10{sup -4} s{sup -1} and correspond to the precipitation intensity from 0.3 to 1.26 mm/hour. These results are in sufficiently good agreement with the results of earlier papers.

  8. Experiment for Investigation of Atmosphere-Magnetosphere Relationship at Mars

    NASA Astrophysics Data System (ADS)

    Vaisberg, O. L.; Koynash, G.; Shestakov, A.; Roman, Z.; Moiseenko, D.; Kirillov, A. S.; Chernouss, S.; Moiseev, P.; Shefov, N.; Semenov, A.; Rodionov, I.; Sosonkin, M.; Ivanov, Y.; Sinyavsky, I.; Sigernes, F.; Berthellier, J.; Leblanc, F.

    2013-12-01

    We are describing an optical experiment for investigation of nightglow of Mars, aeronomic phenomena, helium fluorescence, magnetospheric tail, and escape of planetary ions. Specifically, proposed experiment aimed to investigation of outer envelope of Mars: upper atmosphere and association of its connections with processes in accretion magnetosphere, including atmospheric losses induced by the solar wind. It includes: 1. Registration of spatial distribution of night-side atmospheric glow on Mars in order to determine spatial and temporal properties of electron precipitation for investigation of source regions of these electrons, 2. Registration of spectra of night-side glow for estimation of the energy of precipitation electrons and for analysis of kinetics of electron-excited molecules at different altitudes at Mars, 3. Registration of helium emission 1083 nm at dusk and down for determination of He number density, its height distribution and its variations, and 4. Measurements of CO+ (O+, O2+, CO2+) emission at night-side for determination of atmospheric losses through magnetospheric tail. To study mentioned phenomena we propose the set of instruments that may be used in mission to Mars. Experiment includes 4 optical sensors: all-sky camera, spectrograph, and two photometers. For investigation of spatial and spectral characteristics of night-side upper atmosphere we have chosen spectral interval 200-230 nm. Observations of Martian night glow will be performed with two instruments: all-sky camera (2π field of view), that measures emission in 200-230 nm band (CO) and narrow-angle spectrograph with 1800 - slit in spectral range 200-230 nm with resolution ~ 0.5 nm. This spectral range almost completely free of absorption by O3 and CO2 Recorded spectrum is attributed to specific emitting regions with help of all-sky camera. He emission at 1083 nm is observed with narrow-angle (~ 50) fast-lens photometer. 1083 nm emission of He depends not only on He number density but

  9. Advanced Global Atmospheric Gases Experiment (AGAGE): MIT Contribution

    NASA Technical Reports Server (NTRS)

    Kurylo, Michael

    2003-01-01

    We describe in detail the instrumentation and calibrations used in the ALE, GAGE and AGAGE experiments and present a history of the majority of the anthropogenic ozone- depleting and climate-forcing gases in air based on these experiments. Beginning in 1978, these three successive automated high frequency in-situ experiments have documented the long-term behavior of the measured concentrations of these gases over the past twenty years, and show both the evolution of latitudinal gradients and the high frequency variability due to sources and circulation. We provide estimates of the long-term trends in total chlorine contained in long- lived halocarbons involved in ozone depletion. We summarize interpretations of these measurements using inverse methods to determine trace gas lifetimes and emissions. Finally, we provide a combined observational and modeled reconstruction of the evolution of chlorocarbons by latitude in the atmosphere over the past sixty years which can be used as boundary conditions for interpreting trapped air in glaciers and oceanic measurements of chlorocarbon tracers of the deep oceanic circulation. Some specific conclusions are: (a) International compliance with the Montreal Protocol is so far resulting in chlorofluorocarbon and chlorocarbon mole fractions comparable to target levels, (b) Mole fractions of total chlorine contained in long-lived halocarbons (CCl2F2, CCl3F, CH3CCl3, CCl4, CHClF2, CCl2FCClF2, CH3Cl, CH2Cl2, CHCl3, CCl2=CCl2) in the lower troposphere reached maximum values of about 3.6 ppb in 1993 and are beginning to slowly decrease in the global lower atmosphere, (c) The chlorofluorocarbons have atmospheric lifetimes consistent with destruction in the stratosphere being their principal removal mechanism, (d) Multi-annual variations in chlorofluorocarbon and chlorocarbon emissions deduced from ALUGAGWAGAGE data are consistent approximately with variations estimated independently from industrial production and sales data where

  10. GAPEX: A Ground-Based Atmospheric Profiling Experiment.

    NASA Astrophysics Data System (ADS)

    Smith, W. L.; Rvercomb, H. E.; Howell, H. B.; Woolf, H. M.; Knuteson, R. O.; Decker, R. G.; Lynch, M. J.; Westwater, E. R.; Strauch, R. G.; Moran, K. P.; Stankov, B.; Falls, M. J.; Jordan, J.; Jacobsen, M.; Dabberdt, W. F.; McBeth, R.; Albright, G.; Paneitz, C.; Wright, G.; May, P. T.; Decker, M. T.

    1990-03-01

    During the week 29 October-4 November 1988, a Ground-based Atmospheric Profiling Experiment (GAPEX) was conducted at Denver Stapleton International Airport. The objective of GAPEX was to acquire and analyze atomspheric-temperature and moisture-profile data from state-of-the-art remote sensors. The sensors included a six-spectral-channel, passive Microwave Profiler (MWP), a passive, infrared High-Resolution Interferometer Sounder (HIS) that provides more than 1500 spectral channels, and an active Radio Acoustic Sounding System (RASS). A Cross-Chain Loran Atmospheric Sounding System (CLASS) was used to provide research-quality in situ thermodynamic observations to verify the accuracy and resolution characteristics of each of the three remote sensors. The first results of the project are presented here to inform the meteorological community of the progress achieved during the GAPEX field phase. These results also serve to demonstrate the excellent prospects for an accurate, continuous thermodynamic profiling system to complement NOAA's forthcoming operational wind profiler.

  11. Aerodynamic characteristics of the planetary atmosphere experiments test entry probe

    NASA Technical Reports Server (NTRS)

    Sammonds, R. I.; Kruse, R. L.

    1975-01-01

    The aerodynamic characteristics of the Planetary Atmosphere Experiments Test entry probe were determined experimentally in ballistic range tests over a wide range of Mach and Reynolds numbers, and were compared with full-scale flight results. The ground facility data agreed with the full-scale data within 2 to 3% in drag coefficient, and within 5 to 10% in static stability, at the higher Mach numbers. Comparisons of the flight data with conventional wind-tunnel data indicated a significant disagreement in drag coefficient in the transonic speed range suggestive of important sting or wall interference effects. Variations in drag coefficient with Mach number were very small hypersonically, but variations with Reynolds number were of the order of 15% at a free-stream Mach number of 13 over the Reynolds number range from 10,000 to 1,000,000. Variations in the lift and static-stability curves with Mach number and Reynolds number were also defined.

  12. First Global Observations of Atmospheric COClF from the Atmospheric Chemistry Experiment Mission

    NASA Technical Reports Server (NTRS)

    Fu, Dejian; Boone, Chris D.; Bernath, Peter F.; Weisenstein, Debra K.; Rinsland, Curtis P.; Manney, Gloria L.; Walker, Kaley A.

    2009-01-01

    Carbonyl chlorofluoride (COClF) is an important reservoir of chlorine and fluorine in the Earth's atmosphere. Satellite-based remote sensing measurements of COClF, obtained by the Atmospheric Chemistry Experiment (ACE) for a time period spanning February 2004 through April 2007, have been used in a global distribution study. There is a strong source region for COClF in the tropical stratosphere near 27 km. A layer of enhanced COClF spans the low- to mid-stratosphere over all latitudes, with volume mixing ratios of 40-100 parts per trillion by volume, largest in the tropics and decreasing toward the poles. The COClF volume mixing ratio profiles are nearly zonally symmetric, but they exhibit a small hemispheric asymmetry that likely arises from a hemispheric asymmetry in the parent molecule CCl3F. Comparisons are made with a set of in situ stratospheric measurements from the mid-1980s and with predictions from a 2-D model.

  13. The THS experiment: probing Titan's atmospheric chemistry at low temperature

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, Ella; Upton, Kathleen; Beauchamp, Jack L; Salama, Farid

    2014-06-01

    In Titan’s atmosphere, a complex chemistry between N2 and CH4 occurs at temperatures lower than 200K and leads to the production of heavy molecules and subsequently solid aerosols that form the haze surrounding Titan. The Titan Haze Simulation (THS) experiment has been developed at the NASA Ames COSmIC facility to study Titan’s atmospheric chemistry at low temperature in order to help interpret Cassini’s observational data. In the THS, the chemistry is simulated by plasma in the stream of a supersonic expansion. With this unique design, the gas is jet-cooled to Titan-like temperature 150K) before inducing the chemistry by plasma, and remains at low temperature in the plasma discharge 200K). Different N2-CH4-based gas mixtures can be injected in the plasma, with or without the addition of heavier precursors present as trace elements on Titan. Both the gas phase and solid phase products resulting from the plasma-induced chemistry can be monitored and analyzed using a combination of complementary in situ and ex situ diagnostics.Here we present the complementary results of two studies of the gas and solid phase. A Mass spectrometry analysis of the gas phase has demonstrated that the THS experiment is a unique tool to probe the first and intermediate steps as well as specific chemical pathways of Titan’s atmospheric chemistry at Titan-like temperature. The more complex chemistry, observed in the gas phase when adding trace elements to the initial N2-CH4 mixture, has also been confirmed by an extensive study of the solid phase products: Scanning Electron Microscopy images have shown that aggregates produced in N2-CH4-C2H2-C6H6 mixtures (up to 5 μm in diameter) are much larger than those produced in N2-CH4 mixtures (0.1-0.5 μm), and Nuclear Magnetic Resonance results support a growth evolution of the chemistry when adding acetylene to the N2-CH4 mixture, resulting in the production of more complex hydrogen bonds than with a simple N2-CH4 mixture

  14. An overview of the Soviet Vega balloon experiment and studies of the atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Sagdeev, R. Z.

    1986-01-01

    An overview of the VEGA probe to Venus is given, including a detailed examination of the balloon experiment to study the atmosphere of Venus. The areas of study include the ground network, the global network of radiotelescopes, meteorological measurements, the thermal structure of the Venus atmosphere in the middle cloud layer, atmospheric dynamics, and other results of the VEGA 1 and 2 experiments.

  15. Calibrating Atmospheric Delay for the Cassini Gravitational Wave Experiment

    NASA Technical Reports Server (NTRS)

    Resch, G. M.; Keihm, S. J.; Naudet, C. J.; Riley, A. L.; Tanner, A. B.; Teitelbaum, L. P.; Linfield, R. P.

    2000-01-01

    The Cassini spacecraft together with one of the stations of the Deep Space Network (DSN) have been instrumented to carry out extremely precise Doppler tracking that will be used to search for the direct evidence of Gravitational radiation passing through our solar system. The two-way communications link between the ground antenna and the spacecraft constitute an "antenna" for gravitational waves that would perturb the phase of the RF signal in the link. The experiments will be carried out during the long cruise phase of the spacecraft on its journey to Saturn and will be sensitive to gravitational wave perturbations larger than the noise level fluctuations of 3 x 10(exp -15) as measured in the Allan Standard Deviation domain. The use of simultaneous, coherent X- and Ka-Band up and down signals will reduce the errors associated with charged particle fluctuations in the interplanetary medium and Earth's ionosphere to a negligible level. The primary fluctuations in the phase of the signals both to and from the spacecraft are expected to be caused by fluctuations in water vapor in the Earth's atmosphere We have designed and are testing a new atmospheric calibration system (with duplicate components) to sense line-of-sight water vapor and its physical temperature with a goal of calibrating 95% or more of tropospheric path delay fluctuations during the Cassini Gravitational Wave Experiment (GWE). The critical component of the calibration system consists of a newly designed water vapor radiometer having a I degree sensing beamwidth and 0.01 K brightness temperature stability over hour time scales. Auxiliary instrumentation includes a microwave temperature profiler to retrieve the vertical distribution of the vapor physical temperature, and surface meteorology. A detailed error budget has been developed to account for all of the possible sources of error during calibration of the GWE and will be discussed. Two identical calibration systems have been constructed in order to

  16. Feasibility study: Atmospheric general circulation experiment, volume 1

    NASA Technical Reports Server (NTRS)

    Homsey, R. J. (Editor)

    1981-01-01

    The atmospheric general circulation experiment (AGCE) uses a rotating fluid flow cell assembly. The key technical areas affecting the feasibility of the design and operation of the AGCE are investigated. The areas investigated include materials for the flow cell assembly, thermal design, high voltage power supply design, effective retrieval and handling of experiment data and apparatus configuration. Several materials, DMSO and m-tolunitrile, were selected as candidate fluids for the flow cell principally for their high dielectric constant which permits the high voltage power supply design to be held to 15 kV and still simulate terrestrial gravity. Achievement of a low dissipation factor in the fluid to minimize internal heating from the applied electrical field depends strongly on purification and handling procedures. The use of sapphire as the outer hemisphere for the flow cell provides excellent viewing conditions without a significant impact on attaining the desired thermal gradients. Birefringent effects from sapphire can be held to acceptably low limits. Visualization of flow fluid is achieved through the motion of a dot matrix formed by photochromic dyes. Two dyes found compatible with the candidate fluids are spiropyran and triarylmethane. The observation of the dot motion is accomplished using a flying spot scanner.

  17. Research Experiences for Undergraduates in Estuarine and Atmospheric Processes

    NASA Astrophysics Data System (ADS)

    Aller, J. Y.

    2009-12-01

    Our program in the School of Marine and Atmospheric Sciences at Stony Brook University is unique in emphasizing the interdisciplinary study of coastal ocean and atmospheric processes. We attract a large number of both male and female undergraduate applicants representing diverse ethnic groups from across the country. Many are multi-discipline majors merging geology, biology, chemistry, or physics with engineering, and/or mathematics and welcome the opportunity to combine their academic training to examine environmental problems. Our goal is a program reflective of today’s world and environmental challenges, one that provides a ‘hands-on’ research experience which illustrates the usefulness of scientific research for understanding real-world problems or phenomena, and one in which students are challenged to apply their academic backgrounds to develop intuition about natural systems and processes. Projects this past summer focused on assessing climate change and its effects on coastal environments and processes. Projects addressed the implications of a changing global climate over the next 50 years on hydrologic cycles and coastal environments like barrier islands and beaches, on seasonal weather conditions and extreme events, on aerosols and the Earth’s radiative balance, and on aquatic habitats and biota. Collaborative field and laboratory or computer-based projects involving two or three REU students, graduate students, and several mentors, enable undergraduate students appreciate the importance of teamwork in addressing specific scientific questions or gaining maximum insight into a particular phenomenon or process. We believe that our approach allows students to understand what their role will be as scientists in the next phase of our earth’s evolution.

  18. Performance Improvements to the Lidar Atmospheric Sensing Experiment (LASE)

    NASA Technical Reports Server (NTRS)

    Edwards, W. C.; Petway, L. P.; Antill, C. W., Jr.

    1998-01-01

    Lidar Atmospheric Sensing Experiment (LASE) is the first fully-engineered, modular, tunable, autonomous Differential Absorption Lidar (DIAL) system for the remote measurement of water vapor, aerosols and clouds across the troposphere. It was designed, built and environmentally tested at LARC. LASE was designed to fly aboard a NASA/Ames ER-2 aircraft (NASA's high altitude aircraft) and operate at altitudes from 58,000 to 70,000 feet. Since its first flight on May 11, 1994, it has flown 28 total missions on board the ER-2. LASE has been validated with results showing an accuracy better than the initial requirement for vertical profiles of water vapor in the troposphere. LASE can also deploy on several other aircraft including the NASA P-3 and will fly aboard the NASA DC-8 during the Convection And Moisture EXperiment (CAMEX) in July-September 1998. The tunable laser system of LASE was designed to operate in a double-pulse mode at 5Hz, with energy outputs of up to 15OmJ per pulse in the 813 to 819nm wavelength region and with 99% of the output energy within a spectral interval of 1.06 pm. Sixteen wavelengths were selected to cover the various water vapor absorption cross sections needed for the DIAL measurement. The Ti:Sapphire laser was constructed using a frequency-doubled Nd:YAG laser as the pump source and a single mode diode laser as a injection seeder for the Ti:Al2O3 laser. We have improved the LASE instrument in several important ways. Improvements to the seed source have demonstrated that DFB laser diodes can be used as reliable seed sources on airborne DIAL instruments. The DFB diode has enabled LASE to gather more data and significantly reduced the maintenance required to insure that the system performance requirements are met. The multiwavelength sequential seeding technique is the current method of data collection for LASE. It has the advantages of providing an entire atmospheric coverage of H2O(v) from the ground to the aircraft altitude along a single

  19. Atmospheric Trace Molecule Spectroscopy (ATMOS) Experiment Version 3 data retrievals.

    PubMed

    Irion, Fredrick W; Gunson, Michael R; Toon, Geoff C; Chang, Albert Y; Eldering, Annmarie; Mahieu, Emmanuel; Manney, Gloria L; Michelsen, Hope A; Moyer, Elizabeth J; Newchurch, Michael J; Osterman, Gregory B; Rinsland, Curtis P; Salawitch, Ross J; Sen, Bhaswar; Yung, Yuk L; Zander, Rodolphe

    2002-11-20

    Version 3 of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment data set for some 30 trace and minor gas profiles is available. From the IR solar-absorption spectra measured during four Space Shuttle missions (in 1985, 1992, 1993, and 1994), profiles from more than 350 occultations were retrieved from the upper troposphere to the lower mesosphere. Previous results were unreliable for tropospheric retrievals, but with a new global-fitting algorithm profiles are reliably returned down to altitudes as low as 6.5 km (clouds permitting) and include notably improved retrievals of H2O, CO, and other species. Results for stratospheric water are more consistent across the ATMOS spectral filters and do not indicate a net consumption of H2 in the upper stratosphere. A new sulfuric-acid aerosol product is described. An overview of ATMOS Version 3 processing is presented with a discussion of estimated uncertainties. Differences between these Version 3 and previously reported Version 2 ATMOS results are discussed. Retrievals are available at http://atmos.jpl.nasa.gov/atmos.

  20. Atmospheric observations during the Arctic Clouds in Summer Experiment (ACSE)

    NASA Astrophysics Data System (ADS)

    Tjernström, Michael; Brooks, Barbara; Brooks, Ian; Johnston, Paul; Persson, Ola; Prytherch, John; Salisbury, Dominic; Sedlar, Joseph; Shupe, Matthew; Sotiropoulou, Georgia; Wolfe, Dan

    2015-04-01

    During the SWERUS-C3 expedition, twice across the Barents, Laptev, Kara and East Siberian Seas, on the icebreaker Oden, the Arctic Clouds in Summer Experiment (ACSE) took extensive atmospheric observations during a three month period. This poster presents the observations and some preliminar results. The first leg, starting in Tromsö, Norway, on 5 July and ending at Barrow, Alaska, on 19 August, moved mostly on the outer shelf, in open water or sea ice at about 50/50; the sea iuce was sometimes quite thick and solid although melting was intense. The second leg, starting out from Barrow on 21 August and ending in Tromsö on 5 October, was mostly in either open water or in the marginal ice zone, and saw the onset of the autumn freeze. During the the entire 3-month period we deployed an extensive set of instruments, including both in-situ observations and surface based remote sensing. The in-situ observations included standard meteorology, clouds and visibility as well as surface fluxes observed by eddy-correlation measurements on a bow mast 20-meter above the surface and incoming radiation; 6-hourly soundings were also launched through the whole expedition. The remote sensing instruments include a W-band Doppler cloud radar, scanning microwave radiometers, a 3D scanning Doppler lidar and a 449MHz wind profiling radar. The cloud radar, one radiometer and the lidar were mounted on stabilized platforms.

  1. Infrared experiments for spaceborne planetary atmospheres research. Full report

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The role of infrared sensing in atmospheric science is discussed and existing infrared measurement techniques are reviewed. Proposed techniques for measuring planetary atmospheres are criticized and recommended instrument developments for spaceborne investigations are summarized for the following phenomena: global and local radiative budget; radiative flux profiles; winds; temperature; pressure; transient and marginal atmospheres; planetary rotation and global atmospheric activity; abundances of stable constituents; vertical, lateral, and temporal distribution of abundances; composition of clouds and aerosols; radiative properties of clouds and aerosols; cloud microstructure; cloud macrostructure; and non-LTE phenomena.

  2. SUMS preliminary design and data analysis development. [shuttle upper atmosphere mass spectrometer experiment

    NASA Technical Reports Server (NTRS)

    Hinson, E. W.

    1981-01-01

    The preliminary analysis and data analysis system development for the shuttle upper atmosphere mass spectrometer (SUMS) experiment are discussed. The SUMS experiment is designed to provide free stream atmospheric density, pressure, temperature, and mean molecular weight for the high altitude, high Mach number region.

  3. Discovery Venera surface: Atmosphere geochemistry experiments mission concept

    NASA Technical Reports Server (NTRS)

    Surkov, Yuri A.; Head, James W.; Kremnev, Roald; Nock, K. T.

    1993-01-01

    The phenomenal increase in our understanding of Venus provided by the Magellan Mission has raised a series of focused, fundamental scientific questions about the geochemistry of the surface of Venus, the nature of the lower atmosphere, and the relationship of the lower atmosphere and surface. First, surface geochemical measurements from the Venera/Vega spacecraft showed that widely spaced regions of the venusian plains are made of basalts; thus basalts are significant and may be the only component of the venusian crust. But we lack information on the composition of several key elements of Venus geology: (1) Tessera terrain (which may be outcrops of continental-like non-basaltic crustal material) and steep-sided domes/festoons are promising candidates for non-basaltic geochemically evolved material. The composition of the lower part of the Venusian crust is unknown: however, ejecta from large venusian craters provides us with the possibility of sampling this material on the surface; (2) bulk chemistry (structure and dynamics) of the venusian atmosphere are known. The altitude profiles of water vapor content and minor admixtures relevant to redox conditions in the lower atmosphere (less than 20 km altitude) remain uncertain. Lack of that knowledge means that we do not understand the fine chemical structure of the main mass of the Venusian atmosphere; and (3) thermodynamic models predict that igneous materials on the surface of Venus should react with gases of the venusian atmosphere. But because the water vapor content and redox conditions in the lower atmosphere are not well known, we do not understand the nature of venusian weathering: oxidation, sulfatization, carbonatization, and hydration. The answers to these questions are critical to the understanding of Venus, the most Earth-like of the terrestrial planets.

  4. The Radiometer Atmospheric Cubesat Experiment Post-Launch Results

    NASA Astrophysics Data System (ADS)

    Lim, B.; Misra, S.

    2015-12-01

    The Jet Propulsion Laboratory (JPL) developed the Radiometer Atmospheric CubeSat Experiment (RACE) that was lost during the Orbital 3 (Orb-3) launch anomaly on October 28, 2014. The 3U CubeSat mission would have measured 2 channels of the 183 GHz water vapor line and raised the technology readiness level (TRL) of various subsystems to 6. Despite the launch failure, several hundreds of hours of instrument operation data was taken, including measurements in thermal vacuum of the complete spacecraft system. These data is used to evaluate the 35 nm Indium Phosphide (InP) receivers, and the low noise amplifier (LNA) based internal calibration system. The thermal vacuum measurements included frequent observations of a 'cold' and 'hot' target allowing for various receiver parameters to be calculated. The payload thermal vacuum data show that the receiver front ends performed as expected in terms of the gain (>35 dB) and drift (0.06 dB/K). The data also shows that integration could be performed with decreasing noise up to ~30 seconds, allowing for the system to be calibrated within that time period. The expected spacecraft calibration period would have been every 12 seconds. The injected noise from the load terminated LNA show magnitudes from 50 - 150 K that can be tuned which would meet most requirements. However the temperature coefficient is large at ~3 K/K which is over an order of magnitude larger than typical noise diodes. For nanosatellite class spacecraft, the power required to properly maintain the physical temperature range (±0.1K) would be challenging. On larger spacecraft, this methodology may still be viable, depending on the availability of suitable noise diodes at 183 GHz. While the CubeSat did not take measurements in space, the ground data in the relevant environment and extensive testing allows us to raise the following subsystems to TRL 6: 1) 183 GHz 35 nm InP receiver, 2) 183 GHz direct detect receiver and 3) 183 GHz LNA based calibration system.

  5. Ultraviolet absorption: Experiment MA-059. [measurement of atmospheric species concentrations

    NASA Technical Reports Server (NTRS)

    Donahue, T. M.; Hudson, R. D.; Rawlins, W. T.; Anderson, J.; Kaufman, F.; Mcelroy, M. B.

    1977-01-01

    A technique devised to permit the measurement of atmospheric species concentrations is described. This technique involves the application of atomic absorption spectroscopy and the quantitative observation of resonance fluorescence in which atomic or molecular species scatter resonance radiation from a light source into a detector. A beam of atomic oxygen and atomic nitrogen resonance radiation, strong unabsorbable oxygen and nitrogen radiation, and visual radiation was sent from Apollo to Soyuz. The density of atomic oxygen and atomic nitrogen between the two spacecraft was measured by observing the amount of resonance radiation absorbed when the line joining Apollo and Soyuz was perpendicular to their velocity with respect to the ambient atmosphere. Results of postflight analysis of the resonance fluorescence data are discussed.

  6. The Martian atmosphere - Mariner 9 television experiment progress report.

    NASA Technical Reports Server (NTRS)

    Leovy, C. B.; Briggs, G. A.; Young, A. T.; Smith, B. A.; Pollack, J. B.; Shipley, E. N.; Wildey, R. L.

    1972-01-01

    Atmospheric phenomena appearing in the Mariner 9 television pictures are discussed in detail. The surface of the planet was heavily obscured by a global dust storm during the first month in orbit. Brightness data during this period can be fitted by a semi-infinite scattering and absorbing atmosphere model with a single-scattering albedo in the range 0.70-0.85. This low value suggests that the mean radius of the particles responsible for the obscuration was at least 10 microns. By the end of the second month, this dust storm had largely dissipated, leaving a residual optical depth of about 0.1. Much of the region north of 45 deg N was covered by variable clouds comprising the north polar hood.

  7. The martian atmosphere: Mariner 9 television experiment progress report

    USGS Publications Warehouse

    Leovy, C.B.; Briggs, G.A.; Young, A.T.; Smith, B.A.; Pollack, James B.; Shipley, E.N.; Wildey, R.L.

    1972-01-01

    Atmospheric phenomena appearing in the Mariner 9 television pictures are discussed in detail. The surface of the planet was heavily obscured by a global dust storm during the first month in orbit. Brightness data during this period can be fitted by a semi-infinite scattering and absorbing atmosphere model with a single-scattering albedo in the range 0.70-0.85. This low value suggests that the mean radius of the particles responsible for the obscuration was at least 10 ??m. By the end of the second month, this dust storm had largely dissipated, leaving a residual optical depth ???0.1. Much of the region north of 45??N was covered by variable clouds comprising the north polar hood. The cloud structures revealed extensive systems of lee waves generated by west-to-east flow over irregular terrain. Extensive cloud systems in this region resembled baroclinic wave cyclones. Clouds were also observed over several of the large calderas; these clouds are believed to contain water ice. Several localized dust storms were seen after the global dust storm cleared. These dust clouds appeared to be intensely convective. The convective nature of these storms and the stirring of large dust particles to great heights can be explained by vertical velocities generated by the absorption of solar radiation by the dusty atmosphere. ?? 1972.

  8. NASA Cold Land Processes Experiment (CLPX 2002/03): Atmospheric analyses datasets

    Treesearch

    Glen E. Liston; Daniel L. Birkenheuer; Christopher A. Hiemstra; Donald W. Cline; Kelly Elder

    2008-01-01

    This paper describes the Local Analysis and Prediction System (LAPS) and the 20-km horizontal grid version of the Rapid Update Cycle (RUC20) atmospheric analyses datasets, which are available as part of the Cold Land Processes Field Experiment (CLPX) data archive. The LAPS dataset contains spatially and temporally continuous atmospheric and surface variables over...

  9. Jupiter's atmospheric composition from the Cassini thermal infrared spectroscopy experiment

    NASA Technical Reports Server (NTRS)

    Kunde, V. G.; Flasar, F. M.; Jennings, D. E.; Bezard, B.; Strobel, D. F.; Conrath, B. J.; Nixon, C. A.; Bjoraker, G. L.; Romani, P. N.; Achterberg, R. K.; hide

    2004-01-01

    The Composite Infrared Spectrometer observed Jupiter in the thermal infrared during the swing-by of the Cassini spacecraft. Results include the detection of two new stratospheric species, the methyl radical and diacetylene, gaseous species present in the north and south auroral infrared hot spots; determination of the variations with latitude of acetylene and ethane, the latter a tracer of atmospheric motion; observations of unexpected spatial distributions of carbon dioxide and hydrogen cyanide, both considered to be products of comet Shoemaker-Levy 9 impacts; characterization of the morphology of the auroral infrared hot spot acetylene emission; and a new evaluation of the energetics of the northern auroral infrared hot spot.

  10. Jupiter's atmospheric composition from the Cassini thermal infrared spectroscopy experiment.

    PubMed

    Kunde, V G; Flasar, F M; Jennings, D E; Bézard, B; Strobel, D F; Conrath, B J; Nixon, C A; Bjoraker, G L; Romani, P N; Achterberg, R K; Simon-Miller, A A; Irwin, P; Brasunas, J C; Pearl, J C; Smith, M D; Orton, G S; Gierasch, P J; Spilker, L J; Carlson, R C; Mamoutkine, A A; Calcutt, S B; Read, P L; Taylor, F W; Fouchet, T; Parrish, P; Barucci, A; Courtin, R; Coustenis, A; Gautier, D; Lellouch, E; Marten, A; Prangé, R; Biraud, Y; Ferrari, C; Owen, T C; Abbas, M M; Samuelson, R E; Raulin, F; Ade, P; Césarsky, C J; Grossman, K U; Coradini, A

    2004-09-10

    The Composite Infrared Spectrometer observed Jupiter in the thermal infrared during the swing-by of the Cassini spacecraft. Results include the detection of two new stratospheric species, the methyl radical and diacetylene, gaseous species present in the north and south auroral infrared hot spots; determination of the variations with latitude of acetylene and ethane, the latter a tracer of atmospheric motion; observations of unexpected spatial distributions of carbon dioxide and hydrogen cyanide, both considered to be products of comet Shoemaker-Levy 9 impacts; characterization of the morphology of the auroral infrared hot spot acetylene emission; and a new evaluation of the energetics of the northern auroral infrared hot spot.

  11. On the atmospheric response experiment to a Blue Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Nakamura, Tetsu; Yamazaki, Koji; Honda, Meiji; Ukita, Jinro; Jaiser, Ralf; Handorf, Dörthe; Dethloff, Klaus

    2016-10-01

    We demonstrated atmospheric responses to a reduction in Arctic sea ice via simulations in which Arctic sea ice decreased stepwise from the present-day range to an ice-free range. In all cases, the tropospheric response exhibited a negative Arctic Oscillation (AO)-like pattern. An intensification of the climatological planetary-scale wave due to the present-day sea ice reduction on the Atlantic side of the Arctic Ocean induced stratospheric polar vortex weakening and the subsequent negative AO. Conversely, strong Arctic warming due to ice-free conditions across the entire Arctic Ocean induced a weakening of the tropospheric westerlies corresponding to a negative AO without troposphere-stratosphere coupling, for which the planetary-scale wave response to a surface heat source extending to the Pacific side of the Arctic Ocean was responsible. Because the resultant negative AO-like response was accompanied by secondary circulation in the meridional plane, atmospheric heat transport into the Arctic increased, accelerating the Arctic amplification.

  12. Coherent launch-site atmospheric wind sounder - Theory and experiment

    NASA Astrophysics Data System (ADS)

    Hawley, James G.; Targ, Russell; Henderson, Sammy W.; Hale, Charley P.; Kavaya, Michael J.; Moerder, Daniel

    1993-08-01

    The coherent launch-site atmospheric wind sounder (CLAWS) is a lidar atmospheric wind sensor designed to measure the winds above space launch facilities to an altitude of 20 km. In our development studies, lidar sensor requirements are defined, a system to meet those requirements is defined and built, and the concept is evaluated, with recommendations for the most feasible and cost-effective lidar system for use as an input to a guidance and control system for missile or spacecraft launches. The ability of CLAWS to meet NASA goals for increased safety and launch/mission flexibility is evaluated in a field test program at Kennedy Space Center (KSC) in which we investigate maximum detection range, refractive turbulence, and aerosol backscattering efficiency. The Nd:YAG coherent lidar operating at 1.06 micron with 1-J energy per pulse is able to make real-time measurements of the 3D wind field at KSC to an altitude of 26 km, in good agreement with our performance simulations. It also shows the height and thickness of the volcanic layer caused by the volcanic eruption of Mount Pinatubo in the Philippines.

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

    PubMed

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

    1993-08-20

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

  14. OSS-1/STS-3 Shuttle induced atmosphere experiment

    NASA Technical Reports Server (NTRS)

    Weinberg, J. L.; Giovane, F.; Schuerman, D. W.; Hahn, R. C.

    1983-01-01

    Direct light form the Sun and the sunlit Earth, and indirect light from these same sources reflected off parts of the orbiter and its payload were the two major sources of light seen in the bay during spacecraft day. Brightness arising from sunlight reflected off particulates originating from the spacecraft (corona or induced atmosphere) were tentatively identified. Sources of light observed during spacecraft night include large scale diffuse glows associated with Vernier thruster firings, surface glows on the orbiter in the direction of orbiter n motion, and periodic sky brightness structures observed primarily at 4200 A and 6300 A. Some information was obtained on the size and trajectories of individual contaminant particulates. Astronomical data were obtained from large regions of the Milky Way and zodiacal light, including large regions to within 35 deg of the Sun and possibly closer. Coordinated and sometimes simultaneous observations were successfully made from Hawaii and from STS-3 to provide unique information on atmospheric sources and sinks of radiation.

  15. MEEC, a MSP 2001 Rover Experiment to Measure Electrostatic Charging in the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Ferguson, D. C.; Hillard, G. B.

    2000-01-01

    The Mars Experiment on Electrostatic Charging (MEEC), to be flown on the MSP 2001 Marie Curie Rover, is described. It will measure absolute and relative levels of charging in the Martian atmosphere due to traverses and dust-laden winds.

  16. Atmospheric Chemistry Experiment (ACE) Measurements of Tropospheric and Stratospheric Chemistry and Long-Term Trends

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Bernath, Peter; Boone, Chris; Nassar, Ray

    2007-01-01

    We highlight chemistry and trend measurement results from the Atmospheric Chemistry Experiment (ACE) which is providing precise middle troposphere to the lower thermosphere measurements with a 0.02/cm resolution Fourier transform spectrometer covering 750-4400/cm

  17. Analytical study of the Atmospheric Cloud Physics Laboratory (ACPL) experiments

    NASA Technical Reports Server (NTRS)

    Davis, M. H.

    1977-01-01

    The design specifications of the research laboratory as a Spacelab facility are discussed along with the types of planned experiments. These include cloud formation, freezing and scavenging, and electrical phenomena. A summary of the program conferences is included.

  18. A compilation of studies from Atmospheric Variability Experiment (AVE)

    NASA Technical Reports Server (NTRS)

    Scoggins, J. R.; Fuelberg, H. E.; Carlson, R. D.; Phelps, R. W.; Bellue, D. G.

    1973-01-01

    Five methods for obtaining the sign of vertical motion at various levels in the atmosphere were investigated to determine which gave the best explanation for areas of rain and no-rain in the southeastern United States during the period February 19-22, 1964. The methods used were the terrain-induced vertical motion, the kinematic method including the terrain effect, the adiabatic method, the omega equation, and the vorticity equation combined with Dines' Compensation Principle. Stability and moisture availability were considered but not as extensively as vertical motion. Values of vertical motion obtained by the kinetic method, including orographic lifting produced the best agreement with the observed areas. When terms in the omega equation were added through use of constant multipliers, results comparable to the adiabatic method were obtained. Without this addition large uncertainties occurred. Maps showing areas where terms of the omega equation would indicate positive vertical motion did not correlate well with the observed rainfall patterns.

  19. Planar ion trap (retarding potential analyzer) experiment for atmosphere explorer

    NASA Technical Reports Server (NTRS)

    Hanson, W. B.; Sanatani, S.; Lippincott, C. R.; Zuccaro, D. R.

    1982-01-01

    The retarding potential analyzer and drift meter were carried aboard all three Atmosphere Explorer spacecraft. These instruments measure the total thermal ion concentration and temperature, the bulk thermal ion velocity vector and some limited properties of the relative abundance of H(+), He(+), O(+) and molecular ions. These instruments functioned with no internal failures on all the spacecraft. On AE-E there existed some evidence for external surface contamination that damaged the integrity of the RPA sweep grids. This led to some difficulties in data reduction and interpretation that did not prove to be a disastrous problem. The AE-D spacecraft functioned for only a few months before it re-entered. During this time the satellite suffered from a nutation about the spin axis of about + or - 2 deg. This 2 deg modulation was superimposed upon the ion drift meter horizontal ion arrival angle output requiring the employment of filtering techniques to retrieve the real data.

  20. The Mars Pathfinder atmospheric structure investigation/meteorology (ASI/MET) experiment.

    PubMed

    Schofield, J T; Barnes, J R; Crisp, D; Haberle, R M; Larsen, S; Magalhães, J A; Murphy, J R; Seiff, A; Wilson, G

    1997-12-05

    The Mars Pathfinder atmospheric structure investigation/meteorology (ASI/MET) experiment measured the vertical density, pressure, and temperature structure of the martian atmosphere from the surface to 160 km, and monitored surface meteorology and climate for 83 sols (1 sol = 1 martian day = 24.7 hours). The atmospheric structure and the weather record are similar to those observed by the Viking 1 lander (VL-1) at the same latitude, altitude, and season 21 years ago, but there are differences related to diurnal effects and the surface properties of the landing site. These include a cold nighttime upper atmosphere; atmospheric temperatures that are 10 to 12 degrees kelvin warmer near the surface; light slope-controlled winds; and dust devils, identified by their pressure, wind, and temperature signatures. The results are consistent with the warm, moderately dusty atmosphere seen by VL-1.

  1. The Mars Pathfinder atmospheric structure investigation/meteorology (ASI/MET) experiment

    NASA Technical Reports Server (NTRS)

    Schofield, J. T.; Barnes, J. R.; Crisp, D.; Haberle, R. M.; Larsen, S.; Magalhaes, J. A.; Murphy, J. R.; Seiff, A.; Wilson, G.

    1997-01-01

    The Mars Pathfinder atmospheric structure investigation/meteorology (ASI/MET) experiment measured the vertical density, pressure, and temperature structure of the martian atmosphere from the surface to 160 km, and monitored surface meteorology and climate for 83 sols (1 sol = 1 martian day = 24.7 hours). The atmospheric structure and the weather record are similar to those observed by the Viking 1 lander (VL-1) at the same latitude, altitude, and season 21 years ago, but there are differences related to diurnal effects and the surface properties of the landing site. These include a cold nighttime upper atmosphere; atmospheric temperatures that are 10 to 12 degrees kelvin warmer near the surface; light slope-controlled winds; and dust devils, identified by their pressure, wind, and temperature signatures. The results are consistent with the warm, moderately dusty atmosphere seen by VL-1.

  2. Nucleon decay and atmospheric neutrinos in the Mont Blanc experiment

    NASA Technical Reports Server (NTRS)

    Battistoni, G.; Bellotti, E.; Bologne, G.; Campana, P.; Castagnoli, C.; Chiarella, V.; Ciocio, A.; Cundy, D. C.; Dettorepiazzoli, B.; Fiorini, E.

    1985-01-01

    In the NUSEX experiment, during 2.8 years of operation, 31 fully contained events have been collected; 3 among them are nucleon decay candidates, while the others have been attributed to upsilon interactions. Limits on nucleon lifetime and determinations of upsilon interaction rates are presented.

  3. Nucleon decay and atmospheric neutrinos in the Mont Blanc experiment

    NASA Astrophysics Data System (ADS)

    Battistoni, G.; Bellotti, E.; Bologna, G.; Campana, P.; Castagnoli, C.; Chiarella, V.; Ciocio, A.; Cundy, D. C.; D'Ettorre Piazzoli, B.; Fiorini, E.

    1985-08-01

    In the NUSEX experiment, during 2.8 years of operation, 31 fully contained events have been collected; 3 among them are nucleon decay candidates, while the others have been attributed to upsilon interactions. Limits on nucleon lifetime and determinations of upsilon interaction rates are presented.

  4. Atmospheric X-ray emission experiment for shuttle. [earth atmosphere - radiation counters

    NASA Technical Reports Server (NTRS)

    Goldberg, R. A.; Hallam, K. L.; Emming, J. G.

    1975-01-01

    An experiment designed to measure the spatial, temporal, and energy distribution of X-ray aurorae produced by precipitating electrons, is presented. The experiment will provide vital data on solar-terrestrial relationships that may lead to defining the transfer mechanism that causes certain terrestrial weather events and climatological behavior. An instrument concept is discussed, and is based on a spatially sensitive multiwire proportional counter, combined with collimators to produce X-ray images of the aurorae. An instrument pointing system, on which the counter can be mounted, will provide the required altitude control, and can be operated by a Spacelab payload specialist for full control over its observing and data taking modes.

  5. Initial Jupiter Atmosphere Results from the Galileo Ultraviolet Spectrometer Experiment

    NASA Astrophysics Data System (ADS)

    Pryor, W. R.; Hord, C. W.; Barth, C. A.; Stewart, A. I. F.; McClintock, W. E.; Simmons, K. E.; Ajello, J. M.; West, R. A.; Tobiska, W. K.; Shemansky, D. E.; Sandel, B. R.; Clarke, J. T.

    1996-09-01

    Early Jupiter atmosphere results from the EUV (54--128 nm) and UVS (113--432 nm) spectrometers on Galileo will be presented. The EUV instrument is mounted on the spun section of the orbiter, while the UVS is on the scan platform. Data already returned from the Ganymede-1 (G1) orbit contains less background radiation noise than expected. An EUV spin-scan image at 90deg phase shows the polar auroras and Lyman-alpha dayglow. Simultaneous UVS southern aurora spectra were obtained. A full rotation UVS dark side observation of the north aurora on day 176 shows an emission maximum near 184deg longitude. The spectrum resembles a UVS lab spectrum of 100-eV electrons striking H_2 gas. Methane absorption is evident at short wavelengths, indicating a CH_4 slant penetration depth of ~ 2 x 10(16) /cm(2) . A UVS slew (day 176/00:17-00:50) across the southern auroral zone from midnight to noon shows a two-peaked spatial structure in the H_2 band emissions that is visible at the same longitudes in an HST WFPC-2 H_2 band image (176/03:54) with dawn-to-dusk geometry. Dayside UVS observations obtained on and off the Great Red Spot show H_2 emissions, and absorptions due to aerosols, C_2H_2, C_2H_6, C_2H_4, and NH_3. We will report on the spatial variations in the absorbers. Plans for the upcoming Ganymede-2 (G2) orbit include (1) a UVS full rotation observation of the southern aurora, and (2) a UVS north-south slew with the slit aligned east-west for latitude studies of aerosols, hydrocarbons, and ammonia.

  6. One atmosphere melting experiments on ilmenite basalt 12008

    NASA Technical Reports Server (NTRS)

    Rhodes, J. M.; Lofgren, G. E.; Smith, D. P.

    1979-01-01

    An evaluation of a crystal-fractionation model for Apollo 12 ilmenite basalts with melting experiments under controlled oxygen fugacities is reported. The crystallization sequence including olivine, chromium spinel, and pigeonite phases was determined, showing that the changes in melt composition are dominated by olivine crystallization and the decrease in MgO with a corresponding increase in CaO, Al2O3, and TiO2. It is concluded that the bulk composition of the ilmenite basalts was established by crystallization of olivine and minor spinel prior to the onset of pyroxene and plagioclase.

  7. Recherche de leptons lourds au LEP 2

    NASA Astrophysics Data System (ADS)

    Tafirout, Reda

    En 1989, la mise en opération de la première phase du LEP (le LEP 1), au CERN, a une Energie correspondant a la résonance du boson Z0, a permis d'étudier et de confirmer avec une grande précision le Modèle Standard des interactions électrofaibles. Malgré le succès remarquable de ce modèle à décrire toutes les données expérimentales recueillies jusqu'à ce jour en physique des hautes énergies, ce dernier laisse plusieurs questions sans réponse. Il n'explique pas entre autres pourquoi il n'y a que trois familles de particules dont le neutrino associé est léger et la hiérarchie des masses observées des fermions reste une énigme. Ici, nous nous intéressons à l'existence éventuelle de nouveaux fermions, tels que prédits par des extensions du Modèle Standard. Ces nouveaux fermions ont été recherches au LEP 1, mais en vain, et une limite inférieure sur leur masse d'environ MZ/2 a pu être imposée. La deuxième phase du LEP (le LEP 2) qui a débuté dans l'automne 1995 avec une énergie disponible de √s = 130, et 136 GeV, puis dans l'été 1996 a √s = 161 GeV a permis d'améliorer ces limites. Nous présentons ici la recherche de leptons lourds, neutres (N) et chargés (L+/-), effectuée à partir des données recueillies dans l'automne 1996 avec le détecteur de la collaboration OPAL au LEP 2, à des énergies au centre de masse de √s = 170 et 172 GeV. La luminosité totale intégrée fut de 10.3 pb-1. Un nouveau générateur, EXOTIC, conçu et développé a cette fin, a été utilise pour la simulation des échantillons d'événements Monte Carlo qui ont servi à comparer les données obtenues avec les prédictions théoriques. Plus spécifiquement, nous avons recherché le processus e+e- --> NN où N, pouvant être de type Dirac ou Majorana, se désintègre en un lepton léger standard (e, μ, ou τ) et un boson W+/- virtuel (W+/-*). Pour un N de type Dirac, une limite inférieure sur la masse à 95% de niveau de confiance est obtenue

  8. Possible implications of the atmospheric, the Bugey, and the Los Alamos neutrino experiments

    NASA Astrophysics Data System (ADS)

    Minakata, Hisakazu

    1995-12-01

    A combined analysis of the terrestrial neutrino experiments and the Kamiokande observation of the atmospheric neutrino anomaly is performed under the assumption of the existence of dark-matter-mass neutrinos, as suggested by the recent Los Alamos experiment. In the three-flavor mixing scheme of neutrinos it is shown that the constraints from these experiments are so strong that the patterns of mass hierarchy and flavor mixing of neutrinos are determined almost uniquely depending upon the interpretation of the atmospheric neutrino anomaly.

  9. Atmospheric discharges from nuclear facilities during decommissioning: German experiences

    SciTech Connect

    Braun, H.; Goertz, R.; Weil, L.

    1997-08-01

    In Germany, a substantial amount of experience is available with planning, licensing and realization of decommissioning projects. In total, a number of 18 nuclear power plants including prototype facilities as well as 6 research reactors and 3 fuel cycle facilities have been shut down finally and are at different stages of decommissioning. Only recently the final {open_quotes}green field{close_quotes} stage of the Niederaichbach Nuclear Power Plant total dismantlement project has been achieved. From the regulatory point of view, a survey of the decommissioning experience in Germany is presented highlighting the aspects of production and retention of airborne radioactivity. Nuclear air cleaning technology, discharge limits prescribed in licences and actual discharges are presented. As compared to operation, the composition of the discharged radioactivity is different as well as the off-gas discharge rate. In practically all cases, there is no significant amount of short-lived radionuclides. The discussion further includes lessons learned, for example inadvertent discharges of radionuclides expected not to be in the plants inventory. It is demonstrated that, as for operation of nuclear power plants, the limits prescribed in the Ordinance on Radiological Protection can be met using existing air cleaning technology, Optimization of protection results in public exposures substantially below the limits. In the frame of the regulatory investigation programme a study has been conducted to assess the airborne radioactivity created during certain decommissioning activities like decontamination, segmentation and handling of contaminated or activated parts. The essential results of this study are presented, which are supposed to support planning for decommissioning, for LWRs, Co-60 and Cs-137 are expected to be the dominant radionuclides in airborne discharges. 18 refs., 2 figs., 1 tab.

  10. Rainbows, water droplets, and seeing--slow motion analysis of experiments in atmospheric optics.

    PubMed

    Vollmer, Michael; Möllmann, Klaus-Peter

    2011-10-01

    Many physics processes underlying phenomena in atmospheric optics happen on a rather short time scale such that neither the human eye nor video cameras are able to analyze the details. We report applications of high-speed imaging of laboratory experiments in atmospheric optics with subsequent slow motion analysis. The potential to study respective transient effects is investigated in general and for a few phenomena in detail, in particular for rainbow scattering due to single oscillating droplets during free fall, and for light propagation effects through atmospheric paths with turbulences, leading, e.g., to scintillation of stars or shimmering of mirage images.

  11. Sea level changes under increasing atmospheric CO[sub 2] in a transient coupled ocean-atmosphere GCM experiment

    SciTech Connect

    Gregory, J.M. )

    1993-12-01

    Climate change resulting from the enhanced greenhouse effect of increasing atmospheric CO[sub 2] concentrations is expected to bring about global and local changes in sea level. A global rise in sea level would result from thermal expansion of seawater and from melting of land ice, while changes in ocean dynamics and atmospheric pressure patterns could alter relative sea surface topography. Global and local seal level changes have been diagnosed from a 75-yr experiment with a version of the U.K. Meteorological Office coupled ocean-atmosphere general circulation model in which the CO[sub 2] concentration increases at 1% per year. Over the final decade, the component of mean global average sea level rise caused by thermal expansion is 90 mm; on this time scale, a significant contribution is expected from melting of mountain glaciers, but the model does not represent these. Sea level rises over practically the entire ocean area, but there is considerable variation in the magnitude, showing that the global figure by itself gives only a rough idea of the local effect; the largest rises are found in the northwest Atlantic. It is illustrated how this local variation makes it difficult to estimate global sea level rise from a limited number of coastal stations, as must usually be done in practice. 26 refs., 10 figs., 2 tabs.

  12. Huygens probe mission simulation in Earth's atmosphere: a stratospheric balloon experiment for the Huygens Atmospheric Structure Instrument (HASI)

    NASA Astrophysics Data System (ADS)

    Colombatti, G.; Gaborit, V.; Ferri, F.; Bettanini, C.; Bastianello, S.; Flamini, E.; Antonello, M.; Aboudan, A.; Lion Stoppano, P. F.; Fulchignoni, M.

    2003-04-01

    On May, 30th 2002, a balloon experiment was successfully performed from the ASI stratospheric balloons launch base of Trapani-Milo in Sicily, in order to simulate the descent of the Huygens probe into Titan's atmosphere. This test consisted of the release in the Earth's atmosphere of a 1:1 scale mockup of the Huygens probe, lifted up to the altitude of 32.5 km by means of a stratospheric balloon and decelerated by a parachute. The on-board payload consisted of the HASI instrumentation (pressure, temperature sensors and accelerometers), Huygens SSP tilt sensor, Beagle2 UV sensor and an add-on package of complementary sensors. The descent lasted about 54 minutes and was a unique opportunity to investigate the behaviour of the HASI sensors and to get a real data set for trajectory reconstruction. Other added sensors such as a three axial magnetometer, sun sensors and the tilt sensor were used to investigate the attitude of the probe along the descent. During the flight, all the instrumentation was nominally functioning providing data for the determination of the atmospheric vertical pressure and temperature profiles and the acceleration descent profile of the mockup. The whole data set has been used for the determination of the mockup descent and attitude, and to test the algorithms developed for the Huygens trajectory reconstruction. In the same way, the data analysis improved our understanding of the probe motion (mainly pendulum) and how this motion affects accelerometer measurements. From a scientific point of view, this flight was a success and a new balloon experiment is foreseen in summer 2003 in order to integrate other instruments of the real Huygens probe and to improve and complete the existing results.

  13. ACS experiment for atmospheric studies on "ExoMars-2016" Orbiter

    NASA Astrophysics Data System (ADS)

    Korablev, O. I.; Montmessin, F.; Fedorova, A. A.; Ignatiev, N. I.; Shakun, A. V.; Trokhimovskiy, A. V.; Grigoriev, A. V.; Anufreichik, K. A.; Kozlova, T. O.

    2015-12-01

    ACS is a set of spectrometers for atmospheric studies (Atmospheric Chemistry Suite). It is one of the Russian instruments for the Trace Gas Orbiter (TGO) of the Russian-European "ExoMars" program. The purpose of the experiment is to study the Martian atmosphere by means of two observations regimes: sensitive trace gases measurements in solar occultations and by monitoring the atmospheric state during nadir observations. The experiment will allow us to approach global problems of Mars research such as current volcanism, and the modern climate status and its evolution. Also, the experiment is intended to solve the mystery of methane presence in the Martian atmosphere. Spectrometers of the ACS set cover the spectral range from the near IR-range (0.7 μm) to the thermal IR-range (17 μm) with spectral resolution λ/Δλ reaching 50000. The ACS instrument consists of three independent IR spectrometers and an electronics module, all integrated in a single unit with common mechanical, electrical and thermal interfaces. The article gives an overview of scientific tasks and presents the concept of the experiment.

  14. The Numerical Studies Program for the Atmospheric General Circulation Experiment (AGCE) for Spacelab Flights

    NASA Technical Reports Server (NTRS)

    Fowlis, W. W. (Editor); Davis, M. H. (Editor)

    1981-01-01

    The atmospheric general circulation experiment (AGCE) numerical design for Spacelab flights was studied. A spherical baroclinic flow experiment which models the large scale circulations of the Earth's atmosphere was proposed. Gravity is simulated by a radial dielectric body force. The major objective of the AGCE is to study nonlinear baroclinic wave flows in spherical geometry. Numerical models must be developed which accurately predict the basic axisymmetric states and the stability of nonlinear baroclinic wave flows. A three dimensional, fully nonlinear, numerical model and the AGCE based on the complete set of equations is required. Progress in the AGCE numerical design studies program is reported.

  15. Seasonal-scale Observational Data Analysis and Atmospheric Phenomenology for the Cold Land Processes Experiment

    NASA Technical Reports Server (NTRS)

    Poulos, Gregory S.; Stamus, Peter A.; Snook, John S.

    2005-01-01

    The Cold Land Processes Experiment (CLPX) experiment emphasized the development of a strong synergism between process-oriented understanding, land surface models and microwave remote sensing. Our work sought to investigate which topographically- generated atmospheric phenomena are most relevant to the CLPX MSA's for the purpose of evaluating their climatic importance to net local moisture fluxes and snow transport through the use of high-resolution data assimilation/atmospheric numerical modeling techniques. Our task was to create three long-term, scientific quality atmospheric datasets for quantitative analysis (for all CLPX researchers) and provide a summary of the meteorologically-relevant phenomena of the three MSAs (see Figure) over northern Colorado. Our efforts required the ingest of a variety of CLPX datasets and the execution an atmospheric and land surface data assimilation system based on the Navier-Stokes equations (the Local Analysis and Prediction System, LAPS, and an atmospheric numerical weather prediction model, as required) at topographically- relevant grid spacing (approx. 500 m). The resulting dataset will be analyzed by the CLPX community as a part of their larger research goals to determine the relative influence of various atmospheric phenomena on processes relevant to CLPX scientific goals.

  16. Seasonal-scale Observational Data Analysis and Atmospheric Phenomenology for the Cold Land Processes Experiment

    NASA Technical Reports Server (NTRS)

    Poulos, Gregory S.; Stamus, Peter A.; Snook, John S.

    2005-01-01

    The Cold Land Processes Experiment (CLPX) experiment emphasized the development of a strong synergism between process-oriented understanding, land surface models and microwave remote sensing. Our work sought to investigate which topographically- generated atmospheric phenomena are most relevant to the CLPX MSA's for the purpose of evaluating their climatic importance to net local moisture fluxes and snow transport through the use of high-resolution data assimilation/atmospheric numerical modeling techniques. Our task was to create three long-term, scientific quality atmospheric datasets for quantitative analysis (for all CLPX researchers) and provide a summary of the meteorologically-relevant phenomena of the three MSAs (see Figure) over northern Colorado. Our efforts required the ingest of a variety of CLPX datasets and the execution an atmospheric and land surface data assimilation system based on the Navier-Stokes equations (the Local Analysis and Prediction System, LAPS, and an atmospheric numerical weather prediction model, as required) at topographically- relevant grid spacing (approx. 500 m). The resulting dataset will be analyzed by the CLPX community as a part of their larger research goals to determine the relative influence of various atmospheric phenomena on processes relevant to CLPX scientific goals.

  17. Climate and atmosphere simulator for experiments on ecological systems in changing environments.

    PubMed

    Verdier, Bruno; Jouanneau, Isabelle; Simonnet, Benoit; Rabin, Christian; Van Dooren, Tom J M; Delpierre, Nicolas; Clobert, Jean; Abbadie, Luc; Ferrière, Régis; Le Galliard, Jean-François

    2014-01-01

    Grand challenges in global change research and environmental science raise the need for replicated experiments on ecosystems subjected to controlled changes in multiple environmental factors. We designed and developed the Ecolab as a variable climate and atmosphere simulator for multifactor experimentation on natural or artificial ecosystems. The Ecolab integrates atmosphere conditioning technology optimized for accuracy and reliability. The centerpiece is a highly contained, 13-m(3) chamber to host communities of aquatic and terrestrial species and control climate (temperature, humidity, rainfall, irradiance) and atmosphere conditions (O2 and CO2 concentrations). Temperature in the atmosphere and in the water or soil column can be controlled independently of each other. All climatic and atmospheric variables can be programmed to follow dynamical trajectories and simulate gradual as well as step changes. We demonstrate the Ecolab's capacity to simulate a broad range of atmospheric and climatic conditions, their diurnal and seasonal variations, and to support the growth of a model terrestrial plant in two contrasting climate scenarios. The adaptability of the Ecolab design makes it possible to study interactions between variable climate-atmosphere factors and biotic disturbances. Developed as an open-access, multichamber platform, this equipment is available to the international scientific community for exploring interactions and feedbacks between ecological and climate systems.

  18. The neutral atmosphere temperature experiment. [for thermospheric nitrogen measurement on AEROS satellite

    NASA Technical Reports Server (NTRS)

    Spencer, N. W.; Pelz, D. T.; Niemann, H. B.; Carignan, G. R.; Caldwell, J. R.

    1974-01-01

    The AEROS Neutral Atmosphere Temperature Experiment (NATE) is designed to measure the kinetic temperature of molecular nitrogen in the thermosphere. A quadrupole mass spectrometer tuned to N2 measures the N2 density variation in a small spherical antechamber having a knife-edged orifice which is exposed to the atmosphere at the outer surface of the spacecraft. The changing density of N2 due to the spinning motion of the spacecraft permits determination of the velocity distribution of the N2 from which the temperature is calculated. An alternate mode of operation of the instrument allows measurement of the other gases in the atmosphere as well as N2 permitting determination of the neutral particle composition of the atmosphere.

  19. MIR station atmospheric chemistry investigations: numerical simulation of the future space experiments

    NASA Astrophysics Data System (ADS)

    Timofeyev, Yuriy M.

    1995-12-01

    Regular, long-term, g1obalscale measurements of atmospheric minor gaseous and aerosol composition (MGAC) by means ofdifferent instruments (PHOENIX, OZONE-MIR, ISTOK-1, DOPI) are planned on board the SPECTR and PRIRODA modules of the Space Station MIR during 1995-1998. The main characteristics of these devices are given. The principal goals of the space experiments are: investigations of the spatial and temporal MGAC variations, comparisons of different space-borne atmospheric chemistry sensors and their intercalibration, validation of the space MGAC measurements using different ground-based station and aircraft data, and studies of the molecular absorption in the atmosphere aimed to enhance an accuracy of radiative transfer atmospheric models. Special attention is . devoted to radiative transfer model (line-mixing, line-shift, line-narrowing, Non-LTE effects). The numerical estimations of the errors of the MGAC vertical profile retrievals using different device data are carried out.

  20. Turbulence structure of the marine atmospheric boundary layer observed during the SEMAPHORE experiment

    SciTech Connect

    Durand, P.; Benech, B.; Druilhet, A.; Ferret, B.

    1994-12-31

    The SEMAPHORE experiment was conducted in the Azores region in 1993 and was devoted to mesoscale studies of oceanic and atmospheric circulations, as well as interactions between oceanic and atmospheric boundary layers. From October 4 to November 17, two instrumented aircraft gathered data. One of the major objectives of SEMAPHORE was to study the coupling between the atmospheric and oceanic boundary layers in the vicinity of an oceanic temperature front. This front, associated with the Azores current, was located south of the Santa Maria Island where the aircraft were based. The aim of this paper is to document the turbulent structure of the atmospheric boundary layer, analyzed from aircraft measurements, for two different meteorological situations.

  1. Experiment on the Vernov satellite: Transient energetic processes in the Earth's atmosphere and magnetosphere. Part I: Description of the experiment

    NASA Astrophysics Data System (ADS)

    Panasyuk, M. I.; Svertilov, S. I.; Bogomolov, V. V.; Garipov, G. K.; Barinova, V. O.; Bogomolov, A. V.; Veden'kin, N. N.; Golovanov, I. A.; Iyudin, A. F.; Kalegaev, V. V.; Klimov, P. A.; Kovtyukh, A. S.; Kuznetsova, E. A.; Morozenko, V. S.; Morozov, O. V.; Myagkova, I. N.; Petrov, V. L.; Prokhorov, A. V.; Rozhkov, G. V.; Sigaeva, E. A.; Khrenov, B. A.; Yashin, I. V.; Klimov, S. I.; Vavilov, D. I.; Grushin, V. A.; Grechko, T. V.; Khartov, V. V.; Kudryashov, V. A.; Bortnikov, S. V.; Mzhel'skiy, P. V.; Papkov, A. P.; Krasnopeev, S. V.; Krug, V. V.; Korepanov, V. E.; Belyaev, S.; Demidov, A.; Ferenz, Ch.; Bodnar, L.; Szegedi, P.; Rotkel, H.; Moravskiy, M.; Park, Il; Jeon, Jin-A.; Kim, Ji-In; Lee, Jik

    2016-07-01

    The program of physical studies on the Vernov satellite launched on July 8, 2014 into a polar (640 × 830 km) solar-synchronous orbit with an inclination of 98.4° is presented. We described the complex of scientific equipment on this satellite in detail, including multidirectional gamma-ray detectors, electron spectrometers, red and ultra-violet detectors, and wave probes. The experiment on the Vernov satellite is mainly aimed at a comprehensive study of the processes of generation of transient phenomena in the optical and gamma-ray ranges in the Earth's atmosphere (such as high-altitude breakdown on runaway relativistic electrons), the study of the action on the atmosphere of electrons precipitated from the radiation belts, and low- and high-frequency electromagnetic waves of both space and atmospheric origin.

  2. Space fireworks for upper atmospheric wind measurements by sounding rocket experiments

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.

    2016-01-01

    Artificial meteor trains generated by chemical releases by using sounding rockets flown in upper atmosphere were successfully observed by multiple sites on ground and from an aircraft. We have started the rocket experiment campaign since 2007 and call it "Space fireworks" as it illuminates resonance scattering light from the released gas under sunlit/moonlit condition. By using this method, we have acquired a new technique to derive upper atmospheric wind profiles in twilight condition as well as in moonlit night and even in daytime. Magnificent artificial meteor train images with the surrounding physics and dynamics in the upper atmosphere where the meteors usually appear will be introduced by using fruitful results by the "Space firework" sounding rocket experiments in this decade.

  3. Distribution of atmospheric mercury in northern Southeast Asia and South China Sea during Dongsha Experiment

    NASA Astrophysics Data System (ADS)

    Sheu, Guey-Rong; Lin, Neng-Huei; Lee, Chung-Te; Wang, Jia-Lin; Chuang, Ming-Tung; Wang, Sheng-Hsiang; Chi, Kai Hsine; Ou-Yang, Chang-Feng

    2013-10-01

    Northern South China Sea (SCS) is adjacent to major atmospheric mercury (Hg) emission source regions; however, studies concerning regional atmospheric Hg distribution and cycling are very limited. Accordingly, measurements of atmospheric Hg were conducted in March and April during the 2010 Dongsha Experiment to study its spatial and temporal distribution. Atmospheric Hg was measured at Hengchun and Dongsha Island (Taiwan), Da Nang (Vietnam), Chiang Mai (Thailand) and over the northern SCS. Atmospheric Hg concentrations ranged between 1.54 and 6.83 ng m-3, mostly higher than the Northern Hemisphere background value. Regional wind fields and backward trajectories indicated that the atmospheric Hg concentrations over northern SCS should principally reflect the export of the East Asian Hg emissions by northeast monsoon. However, significantly elevated Hg concentrations were always observed at Da Nang, possibly due to the influence of local Hg emissions. Chiang Mai is located in the intense biomass burning region in northern Thailand. Therefore, atmospheric Hg concentrations at Chiang Mai reflected the influence of regional biomass burning Hg emissions. Two dust storms were encountered at Dongsha Island, one on March 16 and the other on March 21, with atmospheric Hg enhancements. Compared with the 2008 summer values, elevated Hg levels were observed at Dongsha Island in the spring of 2010. Summer air masses were mainly from the deep SCS, representing relatively clean marine air. On the other hand, air masses were from the north in spring, passing eastern China or Taiwan prior to reaching Dongsha Island. Results of this research thus demonstrated the transport of atmospheric Hg from the East Asian continent to northern SCS by regional monsoon activity in spring, but special events, such as biomass burning and dust storms, can also cause enhancements of ambient Hg levels.

  4. The Large-Scale Biosphere-Atmosphere Experiment in Amazonia: Analyzing Regional Land Use Change Effects.

    Treesearch

    Michael Keller; Maria Assunção Silva-Dias; Daniel C. Nepstad; Meinrat O. Andreae

    2004-01-01

    The Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) is a multi-disciplinary, multinational scientific project led by Brazil. LBA researchers seek to understand Amazonia in its global context especially with regard to regional and global climate. Current development activities in Amazonia including deforestation, logging, cattle ranching, and agriculture...

  5. ECOLOGICAL RESEARCH IN THE LARGE-SCALE BIOSPHERE–ATMOSPHERE EXPERIMENT IN AMAZONIA: EARLY RESULTS.

    Treesearch

    M. Keller; A. Alencar; G. P. Asner; B. Braswell; M. Bustamente; E. Davidson; T. Feldpausch; E. Fern ndes; M. Goulden; P. Kabat; B. Kruijt; F. Luizao; S. Miller; D. Markewitz; A. D. Nobre; C. A. Nobre; N. Priante Filho; H. Rocha; P. Silva Dias; C von Randow; G. L. Vourlitis

    2004-01-01

    The Large-scale Biosphere–Atmosphere Experiment in Amazonia (LBA) is a multinational, interdisciplinary research program led by Brazil. Ecological studies in LBA focus on how tropical forest conversion, regrowth, and selective logging influence carbon storage, nutrient dynamics, trace gas fluxes, and the prospect for sustainable land use in the Amazon region. Early...

  6. The Titan Haze Simulation experiment on COSmIC: Probing Titan's atmospheric chemistry at low temperature

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, Ella; Ricketts, Claire L.; Salama, Farid

    2014-11-01

    The aim of the Titan Haze Simulation (THS) experiment is to contribute to a better understanding of aerosol formation in Titan's atmosphere through the study of the chemical formation pathways that link the simpler gas phase molecules resulting from the first steps of the N2-CH4 chemistry, to the more complex gas phase precursors of aerosols; and more specifically, to investigate the role of polycyclic aromatic hydrocarbons (PAHs) and nitrogenated polycyclic aromatic hydrocarbons (PANHs), among other hydrocarbons, in this process. In the THS experiment developed at the NASA Ames Cosmic simulation facility (COSmIC), Titan's atmospheric chemistry is simulated by a pulsed plasma jet expansion at temperature conditions (∼150 K) close to those found in Titan's atmosphere in regions where aerosols are formed. In addition, because of the very short residence time of the gas in the plasma discharge, only the initial steps of the chemistry occur, making the COSmIC/THS a unique tool to study the first and intermediate (when adding heavier precursors to the initial N2-CH4 mixture) steps of Titan's atmospheric chemistry at low temperature as shown in the study presented here. We further illustrate the potential of COSmIC/THS for the simulation of Titan's atmospheric chemistry by presenting very promising results from a preliminary comparison of the laboratory data to data from the Cassini Plasma Spectrometer-Ion Beam Spectrometer (CAPS-IBS) instrument.

  7. From image quality to atmosphere experience: how evolutions in technology impact experience assessment

    NASA Astrophysics Data System (ADS)

    Heynderickx, Ingrid; de Ridder, Huib

    2013-03-01

    Image quality is a concept that for long very well served to optimize display performance and signal quality. New technological developments, however, forced the community to look into higher-level concepts to capture the full experience. Terms as naturalness and viewing experience were used to optimize the full experience of 3D-displays and Ambilight TV. These higher-level concepts capture differences in image quality and differences in perceived depth or perceived viewing field. With the introduction of solid-state lighting, further enhancing the multimedia experience, yet more advanced quality evaluation concepts to optimize the overall experience will be needed in the future.

  8. LABLE: A Multi-Institutional, Student-Led, Atmospheric Boundary Layer Experiment

    SciTech Connect

    Klein, P.; Bonin, T. A.; Newman, J. F.; Turner, D. D.; Chilson, P. B.; Wainwright, C. E.; Blumberg, W. G.; Mishra, S.; Carney, M.; Jacobsen, E. P.; Wharton, S.; Newsom, R. K.

    2015-10-01

    This paper presents an overview of the Lower Atmospheric Boundary Layer Experiment (LABLE), which included two measurement campaigns conducted at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site in Oklahoma during 2012 and 2013. LABLE was conducted as a collaborative effort between the University of Oklahoma (OU), the National Severe Storms Laboratory, Lawrence Livermore National Laboratory (LLNL), and the ARM program. LABLE can be considered unique in that it was designed as a multi-phase, low-cost, multi-agency collaboration. Graduate students served as principal investigators and took the lead in designing and conducting experiments aimed at examining boundary-layer processes. The main objective of LABLE was to study turbulent phenomena in the lowest 2 km of the atmosphere over heterogeneous terrain using a variety of novel atmospheric profiling techniques. Several instruments from OU and LLNL were deployed to augment the suite of in-situ and remote sensing instruments at the ARM site. The complementary nature of the deployed instruments with respect to resolution and height coverage provides a near-complete picture of the dynamic and thermodynamic structure of the atmospheric boundary layer. This paper provides an overview of the experiment including i) instruments deployed, ii) sampling strategies, iii) parameters observed, and iv) student involvement. To illustrate these components, the presented results focus on one particular aspect of LABLE, namely the study of the nocturnal boundary layer and the formation and structure of nocturnal low-level jets. During LABLE, low-level jets were frequently observed and they often interacted with mesoscale atmospheric disturbances such as frontal passages.

  9. Global tropospheric experiment at the Hong Kong Atmosphere Chemistry Measurement Station

    NASA Technical Reports Server (NTRS)

    Carroll, Mary Ann; Wang, Tao

    1995-01-01

    The major activities of the Global Tropospheric Experiment at the Hong Kong Atmospheric Chemistry Measurement Station are presented for the period 1 January - 31 December 1995. Activities included data analysis, reduction, and archiving of atmospheric measurements and sampling. Sampling included O3, CO, SO2, NO, TSP, RSP, and ozone column density. A data archive was created for the surface meteorological data. Exploratory data analysis was performed, including examination of time series, frequency distributions, diurnal variations and correlation. The major results have been or will be published in scientific journals as well as presented at conferences/workshops. Abstracts are attached.

  10. Atlas of the global distribution of atmospheric heating during the global weather experiment

    NASA Technical Reports Server (NTRS)

    Schaack, Todd K.; Johnson, Donald R.

    1991-01-01

    Global distributions of atmospheric heating for the annual cycle of the Global Weather Experiment are estimated from the European Centre for Medium-Range Weather Forecasts (ECMWF) Level 3b data set. Distributions of monthly, seasonally, and annually averaged heating are presented for isentropic and isobaric layers within the troposphere and for the troposphere as a whole. The distributions depict a large-scale structure of atmospheric heating that appears spatially and temporally consistent with known features of the global circulation and the seasonal evolution.

  11. WUSAT-SOLSPEC REXUS 17 Experiment: Measuring Atmospheric Quantities of Oxygen and Sodium

    NASA Astrophysics Data System (ADS)

    Crofts, W.; Austin, F.; Burr, D.; Eckersley-Carr, F.; Ferguson, I.; Gold, R.; Harvard, M.; Tucker Harvey, S.; Beard, O.; Hanbury-Williams, C. J.; Iddles, S.; Kodners, L.; Konsala, M.; Lomath, J.; Vavasour, O.

    2015-09-01

    The WUSAT—SOLSPEC experiment was a proof of concept of a novel approach for analysing the characteristics of an atmosphere with regard to its habitability. Once validated the system could be used in the search for extra-terrestrial life by providing details of the compositions of exoplanet atmospheres. The experiment comprised a free falling unit based on CubeSat specifications that measured the wavelengths of light absorbed by Na and 02 in the atmosphere via solar spectroscopy. Using a wireless communication system, this data was sent to a ground station for analysis. As the free falling unit was unrecoverable, all of the data was transferred through the communication link. The wireless communication link was successfully established and this was the first time such a link has been demonstrated on a REXUS mission. Data was received for 71 seconds after ejection. The solar spectroscopy instrument was unable to clearly distinguish the subtle trends in Na and 02 with altitude due to light intensity variation. Light leakage within the optical system is the probable cause of the significant influence of light intensity variation in the results. Hence, further development is required to fully demonstrate the capabilities of solar spectroscopy for the analysis of an atmosphere from a free falling unit, however the experiment successfully illustrated the operation of all required subsystems and the principle of the optical measurement system.

  12. Atmosphere explorer missions C, D, and E. Spacecraft experiment interface definition study

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Atmosphere Explorer Missions C, D, & E Spacecraft/Experiment Interface Definition Study is discussed. The objectives of the study included an analysis of the accommodation requirements of the experiments for the three missions, an assessment of the overall effect of these requirements on the spacecraft system design and performance, and the detailed definition of all experiment/spacecraft electrical, mechanical, and environmental interfaces. In addition, the study included the identification and definition of system characteristics required to ensure compatibility with the consolidated STADAN and MSFN communications networks.

  13. An experiment for Shuttle aerodynamic force coefficient determination from inflight dynamical and atmospheric measurements

    NASA Technical Reports Server (NTRS)

    Compton, H. R.; Blanchard, R. C.; Walberg, G. D.

    1978-01-01

    A two-phase experiment is proposed which utilizes the Shuttle Orbiter and its unique series of repeated entries into the earth's atmosphere as an airborne in situ aerodynamic testing laboratory. The objective of the experiment is to determine static aerodynamic force coefficients, first of the orbiter, and later of various entry configurations throughout the high speed flight regime, including the transition from free molecule to continuum fluid flow. The objective will be accomplished through analysis of inflight measurements from both shuttle-borne and shuttle-launched instrumented packages. Results are presented to demonstrate the feasibility of such an experiment.

  14. Definition of Atmospheric Science Experiments and Techniques: Wake Zone Mapping Experiments

    NASA Technical Reports Server (NTRS)

    Taeusch, D. R.

    1976-01-01

    The development of a subsatellite system has been proposed for the shuttle program which would provide to the scientific community a platform for experiments which would be tethered to the shuttle spacecraft orbiting at about 200 km altitude. Experiments which can perform measurements of aeronomic interest onboard or utilizing the tethered satellite concept are described and recommended.

  15. Thermospheric Density Fluctuations Derived from the Atmospheric Neutral Density Experiment Risk Reduction Mission

    NASA Astrophysics Data System (ADS)

    Nicholas, A. C.; Budzien, S. A.; Healy, L.; Davis, M.

    2008-12-01

    The Atmospheric Neutral Density Experiment (ANDE) Risk Reduction flight was launched on Dec 9, 2006 and deployed into orbit by the Space Shuttle Discovery on December 21, 2006. The primary mission objective is to test the deployment mechanism from the Shuttle for the ANDE flight in mid 2009. Scientific objectives of the ANDE risk reduction flight include: monitor total neutral density along the orbit for improved orbit determination of resident space objects, monitor the spin rate and orientation of the spacecraft, and provide a test object for polarimetry studies. The two ANDERR spacecraft decayed on December 25, 2007 and May 21, 2008, atmospheric densities derived from observations of the ANDERR spacecraft will be presented and compared to atmospheric models and drivers.

  16. High-energy cosmic-ray fluxes in the Earth atmosphere: Calculations vs experiments

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    A new calculation of the atmospheric fluxes of cosmic-ray hadrons and muons in the energy range 10-105 GeV has been performed for the set of hadron production models, EPOS 1.6, QGSJET II-03, SIBYLL 2.1, and others that are of interest to cosmic-ray physicists. The fluxes of secondary cosmic rays at several levels in the atmosphere are computed using directly data of the ATIC-2, GAMMA experiments, and the model proposed recently by Zatsepin and Sokolskaya as well as the parameterization of the primary cosmic-ray spectrum by Gaisser and Honda. The calculated energy spectra of the hadrons and muon flux as a function of zenith angle are compared with measurements as well as other calculations. The effect of uncertainties both in the primary cosmic-ray flux and hadronic model predictions on the spectra of atmospheric hadrons and muons is considered.

  17. International RADAGAST Experiment in Niamey, Niger: Changes and Drivers of Atmospheric Radiation Balance

    SciTech Connect

    Kassianov, Evgueni I.; McFarlane, Sally A.; Barnard, James C.; Flynn, Connor J.; Slingo, A.; Bharmal, N.; Robinson, G. J.; Turner, David D.; Miller, Mark; Ackerman, Thomas P.; Miller, R.

    2009-03-11

    The Sahara desert is notorious as a source of massive dust storms. This dust dramatically influences the Earth-atmosphere energy budget through reflecting and absorbing the incoming sunlight. However, this budget is poorly understood, and in particular, we lack quantitative understanding of how the diurnal and seasonal variation of meteorological variables and aerosol properties influence the propagation of solar irradiance through the desert atmosphere. To improve our understanding of these influences, coincident and collocated observations of fluxes, measured from both space and the surface, are highly desirable. Recently, the unique capabilities of the African Monsoon Multidisciplinary Analysis (AMMA) Experiment, the Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF), the Geostationary Earth Radiation Budget (GERB) instrument, and the Spinning Enhanced Visible and Infrared Imager (SEVIRI) were combined effectively as part of a large international project: the Radiative Atmospheric Divergence using AMF, GERB data and AMMA Stations (RADAGAST), which took place in Niamey, Niger, in 2006. The RADAGAST objectives, instrumentation, and scientific background are presented in [1]. Initial results from RADAGAST documented the strong radiative impact of a major Saharan dust storm on the Earth’s radiation budget [2]. A special issue of the Journal of Geophysical Research will include a collection of papers with the more complete results from RADAGAST (e.g., [1,3], and references therein). In particular, a year-long time series from RADAGAST are used to investigate (i) the factors that control the radiative fluxes and the divergence of radiation across the atmosphere [3-5], (ii) seasonal changes in the surface energy balance and associated variations in atmospheric constituents (water vapor, clouds, aerosols) [6], and (iii) sensitivity of microphysical, chemical and optical properties of aerosols to their sources and the atmospheric conditions [7]. Here we show

  18. Titan's atmosphere simulation experiment using continuum UV-VUV synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Peng, Z.; Gautier, T.; Carrasco, N.; Pernot, P.; Giuliani, A.; Mahjoub, A.; Correia, J.-J.; Buch, A.; Bénilan, Y.; Szopa, C.; Cernogora, G.

    2013-04-01

    A new reactor, named APSIS for Atmospheric Photochemistry Simulated by Synchrotron, is designed for simulating the reactivity occurring in planetary upper atmospheres. In this reactor, a gas mixture roughly reproducing Titan's main atmosphere composition (N2/CH4 = 90/10) is irradiated by a continuous spectrum in the 60-350 nm range, provided by the DISCO beamline at the SOLEIL synchrotron radiation facility. This spectral range enables the dissociation and ionization of N2 and CH4, as observed in plasma reactors and Titan's ionosphere. The neutral products are detected in situ by quadrupole mass spectrometry and collected with a cryogenic trap for ex situ analysis by gas chromatography-mass spectrometry. The detected reaction products include C2, C3, C4, and probably C5 organic compounds, with important amounts of nitrogen-bearing species: HCN, CH3CN, and C2N2. Neutral mass spectra obtained with APSIS are compared with Ion and Neutral Mass Spectrometer experiments of the Cassini space probe in the upper Titan atmosphere and with other results of current Titan atmosphere chemistry laboratory simulations.

  19. Design of the microsatellites used in the atmospheric neutral density experiment

    NASA Astrophysics Data System (ADS)

    Kalmanson, Phillip C.; Nicholas, Andrew C.; Thonnard, Stefan E.; Galysh, Ivan; Bruninga, Robert

    2005-01-01

    The Atmospheric Neutral Density Experiment (ANDE) is a series of four microsatellites that will study the atmosphere of the Earth from low earth orbit. Each microsatellite is based on a common design; however, each differs in the instrument payloads and the associated science and mission requirements. The primary mission objective is to provide total neutral density along the orbit for improved orbit determination of resident space objects. Each ANDE microsatellite has several secondary goals. It is the unique design of the microsatellites that allows this task to be accomplished. Each microsatellite is a compact, near perfect sphere; this reduces shape and drag errors so that the local density of the atmosphere can be determined by instantaneous tracking variations detected by very high accuracy laser and radar ranging whereby the spacecrafts themselves are the primary sensing instrument. The accuracy of the atmospheric density measurements inferred from the orbital tracking of ANDE microsatellites will be much greater than that achieved by similar experiments in the past or from any currently proposed. Many unique design challenges had to be overcome to achieve the necessary science, mission, and operational requirements as well as severe cost constraints. New methods for parts and assembly fabrication were sought out and implemented. These new methods allowed similar parts to function in each of the microsatellites despite the differences between them. In addition, the command and telemetry links used inexpensive COTS Ham radio transceivers while meeting all the International requirements for operations in the Amateur Satellite Service.

  20. Laboratory Experiments to Investigate the Exchange of Water Between the Atmosphere and Surface on Mars

    NASA Astrophysics Data System (ADS)

    Nikolakakos, G.; Whiteway, J. A.

    2016-12-01

    Laboratory chamber experiments have been carried out to investigate the exchange of water between the atmosphere and surface on Mars. Raman Scattering was applied to detect water uptake by samples of magnesium perchlorate hexahydrate. When exposed to the water vapor pressure and temperatures found at the Phoenix landing site, magnesium perchlorate hexahydrate samples of the size found on Mars began to undergo deliquescence at temperatures above the frost point temperature for pure water ice. Significant water uptake from the atmosphere began to occur within minutes, indicating that bulk deliquescence is likely to occur on present-day Mars. This demonstrates that perchlorates in the surface material can contribute to the hydrological cycle on Mars by absorbing water directly from the atmosphere. Chamber experiments have also been conducted to study adsorption of water on regolith grains. Raman spectroscopy has been applied to study the adsorption properties of zeolites under conditions found at the Phoenix landing site on Mars. Preliminary experimental results indicate that zeolites on the surface of Mars are capable of adsorbing water from the atmosphere on diurnal time scales and that Raman spectroscopy provides a promising method for detecting this process during a landed mission.

  1. Atmospheric-like rotating annulus experiment: gravity wave emission from baroclinic jets

    NASA Astrophysics Data System (ADS)

    Rodda, Costanza; Borcia, Ion; Harlander, Uwe

    2017-04-01

    Large-scale balanced flows can spontaneously radiate meso-scale inertia-gravity waves (IGWs) and are thus in fact unbalanced. While flow-dependent parameterizations for the radiation of IGWs from orographic and convective sources do exist, the situation is less developed for spontaneously emitted IGWs. Observations identify increased IGW activity in the vicinity of jet exit regions. A direct interpretation of those based on geostrophic adjustment might be tempting. However, directly applying this concept to the parameterization of spontaneous imbalance is difficult since the dynamics itself is continuously re-establishing an unbalanced flow which then sheds imbalances by GW radiation. Examining spontaneous IGW emission in the atmosphere and validating parameterization schemes confronts the scientist with particular challenges. Due to its extreme complexity, GW emission will always be embedded in the interaction of a multitude of interdependent processes, many of which are hardly detectable from analysis or campaign data. The benefits of repeated and more detailed measurements, while representing the only source of information about the real atmosphere, are limited by the non-repeatability of an atmospheric situation. The same event never occurs twice. This argues for complementary laboratory experiments, which can provide a more focused dialogue between experiment and theory. Indeed, life cycles are also examined in rotating- annulus laboratory experiments. Thus, these experiments might form a useful empirical benchmark for theoretical and modelling work that is also independent of any sort of subgrid model. In addition, the more direct correspondence between experimental and model data and the data reproducibility makes lab experiments a powerful testbed for parameterizations. Joint laboratory experiment and numerical simulation have been conducted. The comparison between the data obtained from the experiment and the numerical simulations shows a very good

  2. Feasibility study of a zero-gravity (orbital) atmospheric cloud physics experiments laboratory

    NASA Technical Reports Server (NTRS)

    Hollinden, A. B.; Eaton, L. R.

    1972-01-01

    A feasibility and concepts study for a zero-gravity (orbital) atmospheric cloud physics experiment laboratory is discussed. The primary objective was to define a set of cloud physics experiments which will benefit from the near zero-gravity environment of an orbiting spacecraft, identify merits of this environment relative to those of groundbased laboratory facilities, and identify conceptual approaches for the accomplishment of the experiments in an orbiting spacecraft. Solicitation, classification and review of cloud physics experiments for which the advantages of a near zero-gravity environment are evident are described. Identification of experiments for potential early flight opportunities is provided. Several significant accomplishments achieved during the course of this study are presented.

  3. An overview of the spectroscopy of the atmosphere using far infrared emission experiment (SAFIRE)

    NASA Technical Reports Server (NTRS)

    Russell, James M., III

    1991-01-01

    The SAFIRE experiment was conceived to satisfy a long-standing need for simultaneous middle atmosphere observations of ozone and important O(y), HO(y), NO(y), ClO(y), and BrO(y) gases, coupled with dynamics data. This will be accomplished using interferometry and broadband radiometry to sound the Earth limb in the far IR and mid IR, respectively. The experiment will employ the latest developments in detector and cryogenic cooling technology in order to achieve the measurement objectives. Detailed instrument and simulated atmospheric retrieval studies show that important gases such as OH, HO2, H2O2, HDO, N2O5, and HOCl can be observed with good accuracy.

  4. IKONOS imagery for the Large Scale Biosphere–Atmosphere Experiment in Amazonia (LBA).

    Treesearch

    George Hurtt; Xiangming Xiao; Michael Keller; Michael Palace; Gregory P. Asner; Rob Braswell; Brond& #305; Eduardo S. zio; Manoel Cardoso; Claudio J.R. Carvalho; Matthew G. Fearon; Liane Guild; Steve Hagen; Scott Hetrick; Berrien Moore III; Carlos Nobre; Jane M. Read; S& aacute; Tatiana NO-VALUE; Annette Schloss; George Vourlitis; Albertus J. Wickel

    2003-01-01

    The LBA-ECO program is one of several international research components under the Brazilian-led Large Scale Biosphere–Atmosphere Experiment in Amazonia (LBA). The field-oriented research activities of this study are organized along transects and include a set of primary field sites, where the major objective is to study land-use change and ecosystem dynamics, and a...

  5. The THS experiment: Simulating Titan's atmospheric chemistry at low temperature (200 K)

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, Ella; Upton, Kathleen T.; Beauchamp, Jack L.; Salama, Farid

    2016-10-01

    In the Titan Haze Simulation (THS) experiment, Titan's atmospheric chemistry is simulated by plasma discharge in the stream of a supersonic expansion, i.e. at low Titan-like temperature (150 K). Here, we present complementary gas and solid phase analyses of four N2-CH4-based gas mixtures that demonstrate the unique capability of the THS to monitor the chemical growth evolution in order to better understand Titan's chemistry and the origin of aerosol formation.

  6. Apollo experience report: Processing of lunar samples in a sterile nitrogen atmosphere

    NASA Technical Reports Server (NTRS)

    Mcpherson, T. M.

    1972-01-01

    A sterile nitrogen atmosphere processing cabinet line was installed in the Lunar Receiving Laboratory to process returned lunar samples with minimum organic contamination. Design and operation of the cabinet line were complicated by the requirement for biological sterilization and isolation, which necessitated extensive filtration, leak-checking, and system sterilization before use. Industrial techniques were applied to lunar sample processing to meet requirements for time-critical experiments while handling a large flow of samples.

  7. Initial results from a mesoscale atmospheric simulation system and comparisons with the AVE-SESAME I data set. [Atmospheric Variability Experiment-Severe Environmental Storms And Mesoscale Experiment

    NASA Technical Reports Server (NTRS)

    Kaplan, M. L.; Zack, J. W.; Wong, V. C.; Tuccillo, J. J.

    1982-01-01

    The development of a comprehensive mesoscale atmospheric simulation system (MASS) is described in detail. The modeling system is designed for both research and real-time forecast applications. The 14-level numerical model, which has a 48 km grid mesh, can be run over most of North America and the adjacent oceanic regions. The model employs sixth-order accurate numerics, generalized similarity theory boundary-layer physics, a sophisticated cumulus parameterization scheme, and state of the art analysis and initialization techniques. Examples of model output on the synoptic and subsynoptic scales are presented for the AVE-SESAME I field experiment on 10-11 April 1979. The model output is subjectively compared to the observational analysis and the LFM II output on the synoptic scale. Subsynoptic model output is compared to analyses generated from the AVE-SESAME I data set.

  8. Initial results from a mesoscale atmospheric simulation system and comparisons with the AVE-SESAME I data set. [Atmospheric Variability Experiment-Severe Environmental Storms And Mesoscale Experiment

    NASA Technical Reports Server (NTRS)

    Kaplan, M. L.; Zack, J. W.; Wong, V. C.; Tuccillo, J. J.

    1982-01-01

    The development of a comprehensive mesoscale atmospheric simulation system (MASS) is described in detail. The modeling system is designed for both research and real-time forecast applications. The 14-level numerical model, which has a 48 km grid mesh, can be run over most of North America and the adjacent oceanic regions. The model employs sixth-order accurate numerics, generalized similarity theory boundary-layer physics, a sophisticated cumulus parameterization scheme, and state of the art analysis and initialization techniques. Examples of model output on the synoptic and subsynoptic scales are presented for the AVE-SESAME I field experiment on 10-11 April 1979. The model output is subjectively compared to the observational analysis and the LFM II output on the synoptic scale. Subsynoptic model output is compared to analyses generated from the AVE-SESAME I data set.

  9. Three-dimensional computer model for the atmospheric general circulation experiment

    NASA Technical Reports Server (NTRS)

    Roberts, G. O.

    1984-01-01

    An efficient, flexible, three-dimensional, hydrodynamic, computer code has been developed for a spherical cap geometry. The code will be used to simulate NASA's Atmospheric General Circulation Experiment (AGCE). The AGCE is a spherical, baroclinic experiment which will model the large-scale dynamics of our atmosphere; it has been proposed to NASA for future Spacelab flights. In the AGCE a radial dielectric body force will simulate gravity, with hot fluid tending to move outwards. In order that this force be dominant, the AGCE must be operated in a low gravity environment such as Spacelab. The full potential of the AGCE will only be realized by working in conjunction with an accurate computer model. Proposed experimental parameter settings will be checked first using model runs. Then actual experimental results will be compared with the model predictions. This interaction between experiment and theory will be very valuable in determining the nature of the AGCE flows and hence their relationship to analytical theories and actual atmospheric dynamics.

  10. Probing atmospheric mixing and leptonic CP violation in current and future long baseline oscillation experiments

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sabya Sachi; Pasquini, Pedro; Valle, J. W. F.

    2017-08-01

    We perform realistic simulations of the current and future long baseline experiments such as T2K, NOνA, DUNE and T2HK in order to determine their ultimate potential in probing neutrino oscillation parameters. We quantify the potential of these experiments to underpin the octant of the atmospheric angle θ23 as well as the value and sign of the CP phase δCP. We do this both in general, as well as within the predictive framework of a previously proposed [1] benchmark theory of neutrino oscillations which tightly correlates θ23 and δCP.

  11. New experiments to validate the radiation pattern of the Middle Atmosphere Alomar Radar System (MAARSY)

    NASA Astrophysics Data System (ADS)

    Renkwitz, T.; Stober, G.; Latteck, R.; Singer, W.; Rapp, M.

    2013-07-01

    The Middle Atmosphere Alomar Radar System (MAARSY) is a monostatic radar with an active phased array antenna designed for studies of phenomena in the mesosphere and lower thermosphere. Its design in particular the flexible beam forming and steering capability makes it to a powerful instrument to perform observations with high angular and temporal resolution. The knowledge of the actual radiation pattern is crucial to configure and analyze experiments carried out with the radar. The simulated radiation pattern is evaluated by the observation of cosmic radio emissions which are compared to a Global Sky temperature Maps model consisting of the most recent, thorough and accurate radio astronomy surveys. Additionally to these passive receive-only experiments active two-way experiments are presented, which corroborate the findings of the passive experiments.

  12. Planetary Radio Interferometry and Doppler Experiment (PRIDE) for Planetary Atmospheric Studies

    NASA Astrophysics Data System (ADS)

    Bocanegra Bahamon, Tatiana; Cimo, Giuseppe; Duev, Dmitry; Gurvits, Leonid; Molera Calves, Guifre; Pogrebenko, Sergei

    2015-04-01

    The Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a technique that allows the determination of the radial velocity and lateral coordinates of planetary spacecraft with very high accuracy (Duev, 2012). The setup of the experiment consists of several ground stations from the European VLBI Network (EVN) located around the globe, which simultaneously perform Doppler tracking of a spacecraft carrier radio signal, and are subsequently processed in a VLBI-style in phase referencing mode. Because of the accurate examination of the changes in phase and amplitude of the radio signal propagating from the spacecraft to the multiple stations on Earth, the PRIDE technique can be used for several fields of planetary research, among which planetary atmospheric studies, gravimetry and ultra-precise celestial mechanics of planetary systems. In the study at hand the application of this technique for planetary atmospheric investigations is demonstrated. As a test case, radio occultation experiments were conducted with PRIDE having as target ESA's Venus Express, during different observing sessions with multiple ground stations in April 2012 and March 2014. Once each of the stations conducts the observation, the raw data is delivered to the correlation center at the Joint Institute for VLBI in Europe (JIVE) located in the Netherlands. The signals are processed with a high spectral resolution and phase detection software package from which Doppler observables of each station are derived. Subsequently the Doppler corrected signals are correlated to derive the VLBI observables. These two sets of observables are used for precise orbit determination. The reconstructed orbit along with the Doppler observables are used as input for the radio occultation processing software, which consists of mainly two modules, the geometrical optics module and the ray tracing inversion module, from which vertical density profiles, and subsequently, temperature and pressure profiles of Venus

  13. Atmospherically relevant experiments on new particle formation in the CERN CLOUD chamber (Invited)

    NASA Astrophysics Data System (ADS)

    Baltensperger, U.; Almeida, J.; Riccobono, F.; Schobesberger, S.; Kirkby, J.

    2013-12-01

    It is generally agreed that sulfuric acid is a major player in atmospheric new particle formation, however, the concentrations of sulfuric acid in the boundary layer of the ambient atmosphere are not sufficient for pure binary nucleation together with water. Therefore, other ingredients are needed to explain the observed new particle formation rates. A two-fold approach is required here: on the one hand field studies providing evidence for such additional components are to be performed, and on the other hand, laboratory experiments need to investigate the effects of such additional components. The latter has for a long time been hampered by our inability to provide a sufficiently clean environment for such experiments. With the CLOUD chamber at CERN, a number of such experiments have been performed, giving insight into the role of such additional components. Ammonia was shown to enhance the nucleation rates by several orders of magnitude compared to pure binary nucleation, however, was still insufficient to match the observed nucleation rates in the boundary layer (Kirkby et al., 2011). This paper will report on the results of experiments using dimethylamine, or oxidation products of either pinanediol or alpha-pinene as additional components. The experiments were performed in the presence or absence of ions from galactic cosmic rays, as well as with an enhanced ion concentration achieved with a pion bean provided by the CERN Proton Synchrotron. The formation of charged and neutral clusters as well as of new particles was followed by a wide variety of instruments, providing insight into the mechanism of new particle formation. Reference: Kirkby, J., et al., Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation, Nature 476, 429-433 (2011).

  14. The Venus Neutral Atmosphere from the Radio Science Experiment VeRa on Venus Express

    NASA Astrophysics Data System (ADS)

    Tellmann, S.; Haeusler, B.; Paetzold, M.; Bird, M. K.; Tyler, G. L.

    2008-12-01

    The Venus Express Radio Science Experiment VeRa is sounding the Venus neutral atmosphere and ionosphere using the spacecraft radio subsystem in the oneway radio link mode at X-band (8.4 GHz) and S- band (2.3 GHz). An Ultrastable Oscillator (USO) provides a high quality onboard frequency reference source for the derivation of electron density profiles in the ionosphere and profiles of pressure, temperature and neutral number density of the neutral atmosphere. Radial profiles of neutral number density derived from the occultations cover the altitude range 40 to 90 km, which are converted to vertical profiles of temperature and pressure. The polar orbit of Venus Express provides the opportunity to study the atmosphere at all planetocentric latitudes under varying illumination conditions. Five occultation seasons could be covered so far during the Venus Express mission resulting in a data set of more than 150 profiles of the neutral atmosphere. The thermal structure is investigated with regard to the latitudinal and temporal variability. A distinct cold collar region could be observed on both hemispheres. The tropopause altitude increases in this latitude region while the tropopause temperature shows a strong decrease. Profiles of static stability are found to be latitude-dependent and nearly adiabatic in the middle cloud region.

  15. Mass spectrometer-pyrolysis experiment for atmospheric and soil sample analysis on the surface of Mars

    NASA Technical Reports Server (NTRS)

    Mauersberger, Konrad; Mahaffy, Paul; Niemann, Hasso

    1992-01-01

    Results from the Viking mission will form the foundation for future in-depth investigations of atmosphere-surface interactions on Mars. The two Viking landers carried impressive instrumentation to obtain and analyze soil samples: the sites were observed by cameras, and the collector head was located on a long boom and allowed the collection of large samples at various depths. A selection of grain sizes was possible and a distribution system supplied a number of experiments with soil material. Despite stationary vehicles, a wide sampling field was reachable. The GCMS system, responsible for atmospheric as well as surface soil analysis, worked well on both landers. Atmospheric measurements resulted in the determination of the abundance of noble gases as well as of other molecular species. Isotopic composition measurements included the important ratios of C-13/C-12, N-15/N-14, and Ar-36/Ar-40. To verify these past results and to advance detailed studies of noble gas isotope ratios and minor constituents, better instrument sensitivities, higher precision, and lower background contributions are required in future Mars missions. Soil analysis during the Viking mission concentrated on organic material. Heating cycles were performed to 500 C and only water and carbon dioxide were identified. Higher pyrolysis temperatures are of primary importance to advance our understanding of the mineralogy and gas loading of surface material and atmospheric exchange.

  16. Mass spectrometer-pyrolysis experiment for atmospheric and soil sample analysis on the surface of Mars

    NASA Technical Reports Server (NTRS)

    Mauersberger, Konrad; Mahaffy, Paul; Niemann, Hasso

    1992-01-01

    Results from the Viking mission will form the foundation for future in-depth investigations of atmosphere-surface interactions on Mars. The two Viking landers carried impressive instrumentation to obtain and analyze soil samples: the sites were observed by cameras, and the collector head was located on a long boom and allowed the collection of large samples at various depths. A selection of grain sizes was possible and a distribution system supplied a number of experiments with soil material. Despite stationary vehicles, a wide sampling field was reachable. The GCMS system, responsible for atmospheric as well as surface soil analysis, worked well on both landers. Atmospheric measurements resulted in the determination of the abundance of noble gases as well as of other molecular species. Isotopic composition measurements included the important ratios of C-13/C-12, N-15/N-14, and Ar-36/Ar-40. To verify these past results and to advance detailed studies of noble gas isotope ratios and minor constituents, better instrument sensitivities, higher precision, and lower background contributions are required in future Mars missions. Soil analysis during the Viking mission concentrated on organic material. Heating cycles were performed to 500 C and only water and carbon dioxide were identified. Higher pyrolysis temperatures are of primary importance to advance our understanding of the mineralogy and gas loading of surface material and atmospheric exchange.

  17. An overview of the rangelands atmosphere hydrosphere biosphere interaction study experiment in northeastern Asia (RAISE)

    NASA Astrophysics Data System (ADS)

    Sugita, Michiaki; Asanuma, Jun; Tsujimura, Maki; Mariko, Shigeru; Lu, Minjiao; Kimura, Fujio; Azzaya, Dolgorsuren; Adyasuren, Tsokhio

    2007-01-01

    SummaryIntensive observations, analysis and modeling within the framework of the rangelands atmosphere-hydrosphere-biosphere interaction study experiment in northeastern Asia (RAISE) project, have allowed investigations into the hydrologic cycle in the ecotone of forest-steppe, and its relation to atmosphere and ecosystem in the eastern part of Mongolia. In this region, changes in the climate have been reported and a market oriented economy was introduced recently, but their impact on the natural environment is still not well understood. In this RAISE special issue, the outcome is presented of the studies carried out by six groups within RAISE, namely: (1) Land-atmosphere interaction analysis, (2) ecosystem analysis and modeling, (3) hydrologic cycle analysis, (4) climatic modeling, (5) hydrologic modeling, and (6) integration. The results are organized in five relevant categories comprising (i) hydrologic cycle including precipitation, groundwater, and surface water, (ii) hydrologic cycle and ecosystem, (iii) surface-atmosphere interaction, (iv) effect of grazing activities on soils, plant ecosystem and surface fluxes, and (v) future prediction. Comparison with studies on rangelands in other parts of the world, and some future directions of studies still needed in this region are also summarized.

  18. Atmospheric Radiation Measurement Madden-Julian Oscillation Investigation Experiment Field Campaign Report

    SciTech Connect

    Long, Chuck

    2016-07-01

    Every 30–90 days during the Northern Hemisphere winter, the equatorial tropical atmosphere experiences pulses of extraordinarily strong deep convection and rainfall. This phenomenon is referred to as the Madden–Julian Oscillation, or MJO, named after the scientists who identified this cycle. The MJO significantly affects weather and rainfall patterns around the world (Zhang 2013). To improve predictions of the MJO—especially about how it forms and evolves throughout its lifecycle—an international group of scientists collected an unprecedented set of observations from the Indian Ocean and western Pacific region from October 2011 through March 2012 through several coordinated efforts. The coordinated field campaigns captured six distinct MJO cycles in the Indian Ocean. The rich set of observations capturing several MJO events from these efforts will be used for many years to study the physics of the MJO. Here we highlight early research results using data from the Atmospheric Radiation Measurement (ARM) Madden-Julian Oscillation Investigation Experiment (AMIE), sponsored by the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility.

  19. Dispersion experiments using short-term releases of an atmospheric tracer

    SciTech Connect

    Weber, A H; Kurzeja, R J

    1985-01-01

    The Mesoscale Atmospheric Transport Studies (MATS) experiments were undertaken to provide a data base for determining the accuracy of mesoscale atmospheric dispersion model predictions for short term releases. This paper describes the MATS experiments and compares observed dispersion parameters with theory. The movement of the sulfur hexaflouride cloud has been compared with wind sensors placed at several different elevations. The observed sigma-y values are also compared with theory and found to agree well with Pasquill's (1976) method. The aim in the MATS experiments has been to achieve as many sceintific goals as possible while answering the fundamental question of model accuracy. The MATS experiments provide information on crosswind and downwind spread of material. The horizontal spread is obtained by a crosswind system of samplers and downwind spread can be determined by using several arcs. Unfortuantely, budget considerations restricted the sampling to a single arc at about 30km downwind from the release point. Despite this limitation, downwind dispersion results were obtained by collecting a sequence of continuous, relatively-short-time-samples as the plume moved downwind. It was assumed that the structure of the plume changed slowly as it moved across the sampling arc. 6 refs., 4 figs., 1 tab.

  20. Investigating Titan's Atmospheric Chemistry at Low Temperature with the Titan Haze Simulation Experiment

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, E. M.; Salama, F.

    2012-12-01

    Titan, Saturn's largest satellite, possesses a dense atmosphere (1.5 bar at the surface) composed mainly of N2 and CH4. The solar radiation and electron bombardment from Saturn's magnetosphere induces a complex organic chemistry between these two constituents leading to the production of more complex molecules and subsequently to solid aerosols. These aerosols in suspension in the atmosphere form the haze layers giving Titan its characteristic orange color. Since 2004, the instruments onboard the Cassini orbiter have produced large amounts of observational data, unraveling a chemistry much more complex than what was first expected, particularly in Titan's upper atmosphere. Neutral, positively and negatively charged heavy molecules have been detected in the ionosphere of Titan, including benzene (C6H6) and toluene (C6H5CH3). The presence of these critical precursors of polycyclic aromatic hydrocarbon (PAH) compounds suggests that PAHs might play a role in the production of Titan's aerosols. The aim of the Titan Haze Simulation (THS) experiment, developed at the NASA Ames COSmIC facility, is to study the chemical pathways that link the simple molecules resulting from the first steps of the N2-CH4 chemistry to benzene, and to PAHs and nitrogen-containing PAHs (PANHs) as precursors to the production of solid aerosols. In the THS experiment, Titan's atmospheric chemistry is simulated by plasma in the stream of a supersonic expansion. With this unique design, the gas mixture is cooled to Titan-like temperature (~150K) before inducing the chemistry by plasma discharge. Due to the short residence time of the gas in the plasma discharge, the THS experiment can be used to probe the first and intermediate steps of Titan's chemistry by injecting different gas mixtures in the plasma. The products of the chemistry are detected and studied using two complementary techniques: Cavity Ring Down Spectroscopy and Time-Of-Flight Mass Spectrometry. Thin tholin deposits are also produced

  1. Liquid and atmospheric ammonia concentrations from a dairy lagoon during an aeration experiment

    NASA Astrophysics Data System (ADS)

    Rumburg, Brian; Neger, Manjit; Mount, George H.; Yonge, David; Filipy, Jenny; Swain, John; Kincaid, Ron; Johnson, Kristen

    Ammonia emissions from agriculture are an environmental and human health concern, and there is increasing pressure to reduce emissions. Animal agriculture is the largest global source of ammonia emissions and on a per cow basis dairy operations are the largest emitters. The storage and disposal of the dairy waste is one area where emissions can be reduced, aerobic biological treatment of wastewater being a common and effective way of reducing ammonia emissions. An aeration experiment in a dairy lagoon with two commercial aerators was performed for 1 month. Liquid concentrations of ammonia, total nitrogen, nitrite and nitrate were monitored before, during and after the experiment and atmospheric ammonia was measured downwind of the lagoon using a short-path differential optical absorption spectroscopy (DOAS) instrument with 1 ppbv sensitivity. No changes in either liquid or atmospheric ammonia concentrations were detected throughout the experiment, and neither dissolved oxygen, nitrite nor nitrate could be detected in the lagoon at any time. The average ammonia concentration at 10 sampling sites in the lagoon at a depth of 0.15 m was 650 mg l -1 and at 0.90 m it was 700 mg l -1 NH 3-N. The average atmospheric ammonia concentration 50 m downwind was about 300 ppbv. The 0.90 m depth total nitrogen concentrations and total and volatile solids concentrations decreased during the experiment due to some mixing of the lagoon but the 0.15 m depth concentrations did not decrease indicating that the aerators were not strong enough to mix the sludge off the bottom into the whole water column.

  2. Vertical atmospheric variability measured above water during the FESTER experiment: first results

    NASA Astrophysics Data System (ADS)

    Maritz, Benita; Koago, Mokete S.; Wainman, Carl K.; Gardener, M. E.; Gunter, Willie H.; van Eijk, Alexander M. J.

    2016-10-01

    The First European South African Experiment (FESTER) was conducted over about a 10 month period at the Institute of Maritime Technology (IMT) in False Bay, South Africa. One of the important goals was to validate atmospheric refraction and turbulence models. To achieve this goal it was required to measure the vertical profile of meteorological parameters and compare this to model predictions. A special helium kite balloon (Helikite) was used as lifting device for weather and temperature sensors to obtain a measured vertical air profile. This measurement was conducted in the middle of the atmospheric path for the principal electro-optic transmission link monitoring equipment (i.e. scintillometer and multi-spectral radiometer-transmissometer system). First results will focus on the vertical air temperature profile shape as function of general environmental conditions and the comparison to model predictions.

  3. GLACE: The Global Land-Atmosphere Coupling Experiment Part 2: Analysis

    NASA Technical Reports Server (NTRS)

    Guo, Zhichang; Dirmeyer, Paul A.; Koster, Randal D.; Bonan, Gordon; Chan, Edmond; Cox, Peter; Gordon, C. T.; Kanae, Shinjiro; Kowalczyk, Eva; Lawrence, David

    2005-01-01

    The twelve weather and climate models participating in the Global Land-Atmosphere Coupling Experiment (GLACE) show both a wide variation in the strength of land-atmosphere coupling and some intriguing commonalities. In this paper, we address the causes of variations in coupling strength - both the geographic variations within a given model and the model-to-model differences. The ability of soil moisture to affect precipitation is examined in two stages, namely, the ability of the soil moisture to affect evaporation, and the ability of evaporation to affect precipitation. Most of the differences between the models and within a given model are found to be associated with the first stage - an evaporation rate that varies strongly and consistently with soil moisture tends to lead to a higher coupling strength. The first stage differences reflect identifiable differences in model parameterization and model climate. Intermodel differences in the evaporation-precipitation connection, however, also play a key role.

  4. Inferring the unobserved chemical state of the atmosphere: idealized data assimilation experiments

    NASA Astrophysics Data System (ADS)

    Knote, C. J.; Barré, J.; Eckl, M.; Hornbrook, R. S.; Wiedinmyer, C.; Emmons, L. K.; Orlando, J. J.; Tyndall, G. S.; Arellano, A. F.

    2015-12-01

    Chemical data assimilation in numerical models of the atmosphere is a venture into uncharted territory, into a world populated by a vast zoo of chemical compounds with strongly non-linear interactions. Commonly assimilated observations exist for only a selected few of those key gas phase compounds (CO, O3, NO2), and assimilating those in models assuming linearity begs the question of: To what extent we can infer the remainder to create a new state of the atmosphere that is chemically sound and optimal? In our work we present the first systematic investigation of sensitivities that exist between chemical compounds under varying ambient conditions in order to inform scientists on the potential pitfalls when assimilating single/few chemical compounds into complex 3D chemistry transport models. In order to do this, we developed a box-modeling tool (BOXMOX) based on the Kinetic PreProcessor (KPP, http://people.cs.vt.edu/~asandu/Software/Kpp/) in which we can conduct simulations with a suite of 'mechanisms', sets of differential equations describing atmospheric photochemistry. The box modeling approach allows us to sample a large variety of atmospheric conditions (urban, rural, biogenically dominated, biomass burning plumes) to capture the range of chemical conditions that typically exist in the atmosphere. Included in our suite are 'lumped' mechanisms typically used in regional and global chemistry transport models (MOZART, RACM, RADM2, SAPRC99, CB05, CBMZ) as well as the Master Chemical Mechanism (MCM, U. Leeds). We will use an Observing System Simulation Experiment approach with the MCM prediction as 'nature' or 'true' state, assimilating idealized synthetic observations (from MCM) into the different ‚lumped' mechanisms under various environments. Two approaches to estimate the sensitivity of the chemical system will be compared: 1) adjoint: using Jacobians computed by KPP and 2) ensemble: by perturbing emissions, temperature, photolysis rates, entrainment, etc., in

  5. Investigating the Martian Atmosphere with the High Resolution Stereo Camera Experiment (HRSC) onboard Mars Express

    NASA Astrophysics Data System (ADS)

    Hoffmann, H.; Markiewicz, W.

    Imaging Mars is one of the main goals of the European Mars Express mission and will be performed by the German High Resolution Stereo Camera (HRSC). The HRSC experiment is a pushbroom scanning instrument with 9 CCD line detectors mounted in parallel on the focal plane. Its unique feature is the ability to obtain nearly simultaneously imaging data at high resolution of 10 m/pixel, with along- track triple stereo, with four colours, and at five different phase angles, thus avoiding any time -dependent variations of the observation conditions. An additional Super- Resolution Channel (HRSC-SRC) - a framing device - will yield nested-in images in the meter-range thus serving as the sharpening eye for detailed studies. The instrument will obtain images containing morphologic and topographic information at high spatial and vertical resolution. The flight hardware has been delivered in January 2002 for accommodation on the spacecraft. Main goals of the HRSC on Mars Express are related to investigate Martian geosciences with special emphasis on the evolution of the Martian surface in general, the evolution of volcanism, and the role of water throughout the Martian history. This includes the detailed analysis of surface-atmosphere interactions by investigating e.g. eolian landforms , variable surface features, dust devils, the polar caps, and condensates . The stereo and multi- phase angle capabilit ies of HRSC allow to quantitatively assess the optical density of the atmosphere during standard nadir observations and will be used to investigate cloud topography as well as the velocity of dust devils and clouds. Special imaging and operation modes have been implemented to enable dedicated atmospheric observations like limb sans in order to determine the vertical structure of the atmosphere in dependence of daytime, season, latitude, and geographic position. Thes e observations will be performed at regular intervals. HRSC-SCR observations at far-distance (i.e. near apoapsis

  6. Impact of aerosols present in Titan's atmosphere on the CASSINI radar experiment

    NASA Astrophysics Data System (ADS)

    Rodriguez, S.; Paillou, P.; Dobrijevic, M.; Ruffié, G.; Coll, P.; Bernard, J. M.; Encrenaz, P.

    2003-07-01

    Simulations of Titan's atmospheric transmission and surface reflectivity have been developed in order to estimate how Titan's atmosphere and surface properties could affect performances of the Cassini radar experiment. In this paper we present a selection of models for Titan's haze, vertical rain distribution, and surface composition implemented in our simulations. We collected dielectric constant values for the Cassini radar wavelength (˜2.2 cm) for materials of interest for Titan: liquid methane, liquid mixture of methane-ethane, water ice, and light hydrocarbon ices. Due to the lack of permittivity values for Titan's haze particles in the microwave range, we performed dielectric constant ( ɛr) measurements around 2.2 cm on tholins synthesized in laboratory. We obtained a real part of ɛr in the range of 2-2.5 and a loss tangent between 10 -3 and 5×10 -2. By combining aerosol distribution models (with hypothetical condensation at low altitudes) to surface models, we find the following results: (1) Aerosol-only atmospheres should cause no loss and are essentially transparent for Cassini radar, as expected by former analysis. (2) However, if clouds are present, some atmospheric models generate significant attenuation that can reach -50 dB, well below the sensitivity threshold of the receiver. In such cases, a 13.78 GHz radar would not be able to measure echoes coming from the surface. We thus warn about possible risks of misinterpretation if a "wet atmosphere" is not taken into account. (3) Rough surface scattering leads to a typical response of ˜-17 dB. These results will have important implications on future Cassini radar data analysis.

  7. Atmospheric Model Effects on Infrasound Source Inversion from the Source Physics Experiments

    NASA Astrophysics Data System (ADS)

    Preston, L. A.; Aur, K. A.

    2016-12-01

    The Source Physics Experiments (SPE) consist of a series of underground explosive shots at the Nevada National Security Site (NNSS) designed to gain an improved understanding of the generation and propagation of physical signals in the near and far field. Characterizing the acoustic and infrasound source mechanism from underground explosions is of great importance in non-proliferation activities. To this end we perform full waveform source inversion of infrasound data collected from SPE shots at distances from 300 m to 1 km and frequencies up to 20 Hz. Our method requires estimating the state of the atmosphere at the time of each shot, computing Green's functions through these atmospheric models, and subsequently inverting these signals in the frequency domain to obtain a source time function. To estimate the state of the atmosphere at the time of the shot, we utilize two different datasets: North American Regional Reanalysis data, a comprehensive but lower resolution dataset, and locally obtained sonde and surface weather observations. We synthesize Green's functions through these atmospheric models using Sandia's moving media acoustic propagation simulation suite. These models include 3-D variations in topography, temperature, pressure, and wind. We will compare and contrast the atmospheric models derived from the two weather datasets and discuss how these differences affect computed source waveforms and contribute to modeling uncertainty. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  8. Huygens Atmospheric Structure Instrument (HASI) test by a stratospheric balloon experiment

    NASA Astrophysics Data System (ADS)

    Fulchignoni, M.; Gaborit, V.; Aboudam, A.; Angrilli, F.; Antonello, M.; Bastianello, S.; Bettanini, C.; Bianchini, G.; Colombatti, G.; Ferri, F.; Lion Stoppato, P.

    2002-09-01

    We developped a series of balloon experiments parachuting a 1:1 scale mock up of the Huygens probe from an altitude larger than 30 km in order to simulate at planetary scale the final part of the descent of the probe in the Titan atmosphere. The Earth atmosphere represents a natural laboratory where most of the physical parameters meet quite well the bulk condition of Titan's environment, with the exception of temperature. A first balloon experiment has been carried out in June 2001 and the results have been reported at the last DPS (V. Gaborit et al., BAAS 33, 38.03) The mock up of the probe descending in the Titan atmosphere for the Huygens Cassini Mission has been successfully launched with stratospheric balloon from Italian Space Agency Base "Luigi Broglio" in Sicily and recovered on May 30th 2002. The probe has been lifted at 32 km altitude and then released to perform a 45 minutes descent decelerated by parachute, to simulate Huygens mission at Titan. Preliminary aerodynamics study of the probe has focused on the achievement of a descent velocity profile and a spin rate profile, satisfying the Huygens mission to Titan requirements. The descent velocity and spin rate have been calculated by solving a system of ODE describing the translational and rotational motion of the probe trough the earth atmosphere during parachute aided descent Results of these calculations have driven the choice of an appropriate angle of attack of the blades in the bottom of the probe and ballast weight during flight. The probe is hosting spares of HASI sensors, housekeeping sensors and other dedicated sensors, Beagle II UV Sensors and Huygens SSP Tilt Sensor, for a total of 77 acquired sensor channels, sampled during ascent, drift and descent phase. Main goals are i) to verify sensor performance and perform a realistic functional test in dynamical and environmental conditions similar to those during the descent in Titan atmosphere; ii) to investigate impact at ground to check the

  9. Pressure Contact Sounding Data for NASA's Atmospheric Variability Experiment (AVE 3)

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.; Hill, C. K.; Turner, R. E.; Long, K. E.

    1975-01-01

    The basic rawinsonde data are described at each pressure contact from the surface to sounding termination for the 41 stations participating in the AVE III measurement program that began at 0000 GMT on February 6 and ended at 1200 GMT on February 7, 1975. Soundings were taken at 3-hour intervals during a large period of the experiment from most stations within the United States east of about 105 degrees west longitude. Methods of data processing, change in reduction scheme since the AVE II pilot experiment, and data accuracy are briefly discussed. An example of contact data is presented, and microfiche cards of all the contact data are included in the appendix. The AVE III project was conducted to better understand and establish the extent of applications for meteorological satellite sensor data through correlative ground truth experiments and to provide basic experimental data for use in studies of atmospheric scales of-motion interrelationships.

  10. Pressure contact sounding data for NASA's Atmospheric Variability Experiment (AVE 2). [rawinsondes

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.; Turner, R. E.

    1975-01-01

    The basic rawinsonde data are described at each pressure contact from the surface to sounding termination for the 54 stations participating in the AVE 2 pilot experiment. Soundings were taken at three-hour intervals from stations within the United States east of about 105 degrees west longitude. Methods of data reduction and estimates of data accuracy are discussed. Examples of the data records produced are shown. The AVE 2 pilot experiment was conducted as part of NASA's program to better understand and establish the extent of applications for meteorological satellite sensor data through correlative ground truth experiments and to provide basic experimental data for use in studies of atmospheric scales-of-motion interrelationships.

  11. An alpha particle experiment for chemical analysis of the Martian surface and atmosphere.

    NASA Technical Reports Server (NTRS)

    Economou, T. E.; Turkevich, A. L.; Patterson, J. H.

    1973-01-01

    An alpha particle experiment similar to the one performed successfully on the Surveyor lunar missions is described. It is designed to provide a chemical analysis of the Martian surface and atmosphere. Analyses of rocks of known and unknown compositions have been made under simulated Martian conditions. The accuracies attained are generally comparable to those of the Surveyor lunar analyses. Improvements have been achieved in determining carbon and oxygen, so that a few per cent of water or carbonates in rocks can be detected. Some aspects of the integration of such an experiment with the spacecraft, a possible mission profile, and some other problems associated with a soft-landing mission to Mars are discussed. The importance of such a chemical analysis experiment in answering current questions about the nature and history of Martian surface material and its suitability for life processes is presented.

  12. Atmospheric pressure creep experiments using highly dense fine-grained mineral aggregates

    NASA Astrophysics Data System (ADS)

    Hiraga, T.; Miyazaki, T.; Tasaka, M.; Sueyoshi, K.; Nakakoji, S.; Koizumi, S.; Yoshida, H.

    2012-12-01

    Historically in mineral and rock physics, atmospheric pressure creep tests have been used extensively to study the rheological properties of minerals through deformation of single crystals. This technique has several advantages including minimal friction effects on the loading column, which allows excellent stress resolution on the sample, and stable temperature control, which allows long duration experiments at relatively slow strain rates. The downside of atmospheric pressure experiments on polycrystalline samples is that cavities and cracks are easily introduced during the test, resulting in brittle failure of the specimen. It is generally found that the confining pressure should be larger than the applied differential stress to avoid failure due to microcracking. Consequently very few creep experiments under atmospheric pressure have been conducted on polycrystalline samples. We revisit this classic method of atmospheric pressure creep experiments by developing a technique to synthesize very fine grained aggregates with essentially zero porosity. So far, we are able to reach even 200 micron grain size for certain type of mineral assemblies. During grain size sensitive creep, we expect that the differential stress applied to the samples can be reduced 100 to 1000 times the stress to deform coarser grained samples at the same strain rate condition by reducing grain size of one order of magnitude. Taking into account of ~10 micron grain size as a common value in conventional experiments, we should be able to reduce the applied stress of > 2500 times. Such lowering the applied stress will help to prevent cracking and/or cavitation in the samples. Using this technique, we have been able to demonstrate (i) superplasticity, (ii) microstructural development comparable to that in observed natural mylonites, (iii) flow strength as a function of stress, grain size and temperature, (iv) the effect of the fraction of second phase on flow strength in poly-phase materials, (v

  13. Focal and Ambient Processing of Built Environments: Intellectual and Atmospheric Experiences of Architecture.

    PubMed

    Rooney, Kevin K; Condia, Robert J; Loschky, Lester C

    2017-01-01

    Neuroscience has well established that human vision divides into the central and peripheral fields of view. Central vision extends from the point of gaze (where we are looking) out to about 5° of visual angle (the width of one's fist at arm's length), while peripheral vision is the vast remainder of the visual field. These visual fields project to the parvo and magno ganglion cells, which process distinctly different types of information from the world around us and project that information to the ventral and dorsal visual streams, respectively. Building on the dorsal/ventral stream dichotomy, we can further distinguish between focal processing of central vision, and ambient processing of peripheral vision. Thus, our visual processing of and attention to objects and scenes depends on how and where these stimuli fall on the retina. The built environment is no exception to these dependencies, specifically in terms of how focal object perception and ambient spatial perception create different types of experiences we have with built environments. We argue that these foundational mechanisms of the eye and the visual stream are limiting parameters of architectural experience. We hypothesize that people experience architecture in two basic ways based on these visual limitations; by intellectually assessing architecture consciously through focal object processing and assessing architecture in terms of atmosphere through pre-conscious ambient spatial processing. Furthermore, these separate ways of processing architectural stimuli operate in parallel throughout the visual perceptual system. Thus, a more comprehensive understanding of architecture must take into account that built environments are stimuli that are treated differently by focal and ambient vision, which enable intellectual analysis of architectural experience versus the experience of architectural atmosphere, respectively. We offer this theoretical model to help advance a more precise understanding of the

  14. Focal and Ambient Processing of Built Environments: Intellectual and Atmospheric Experiences of Architecture

    PubMed Central

    Rooney, Kevin K.; Condia, Robert J.; Loschky, Lester C.

    2017-01-01

    Neuroscience has well established that human vision divides into the central and peripheral fields of view. Central vision extends from the point of gaze (where we are looking) out to about 5° of visual angle (the width of one’s fist at arm’s length), while peripheral vision is the vast remainder of the visual field. These visual fields project to the parvo and magno ganglion cells, which process distinctly different types of information from the world around us and project that information to the ventral and dorsal visual streams, respectively. Building on the dorsal/ventral stream dichotomy, we can further distinguish between focal processing of central vision, and ambient processing of peripheral vision. Thus, our visual processing of and attention to objects and scenes depends on how and where these stimuli fall on the retina. The built environment is no exception to these dependencies, specifically in terms of how focal object perception and ambient spatial perception create different types of experiences we have with built environments. We argue that these foundational mechanisms of the eye and the visual stream are limiting parameters of architectural experience. We hypothesize that people experience architecture in two basic ways based on these visual limitations; by intellectually assessing architecture consciously through focal object processing and assessing architecture in terms of atmosphere through pre-conscious ambient spatial processing. Furthermore, these separate ways of processing architectural stimuli operate in parallel throughout the visual perceptual system. Thus, a more comprehensive understanding of architecture must take into account that built environments are stimuli that are treated differently by focal and ambient vision, which enable intellectual analysis of architectural experience versus the experience of architectural atmosphere, respectively. We offer this theoretical model to help advance a more precise understanding of the

  15. Lessons Learned from the Bay Region Atmospheric Chemistry Experiment (BRACE) and Implications for Nitrogen Management of Tampa Bay

    EPA Science Inventory

    Results from air quality modeling and field measurements made as part of the Bay Region Atmospheric Chemistry Experiment (BRACE) along with related scientific literature were reviewed to provide an improved estimate of atmospheric reactive nitrogen (N) deposition to Tampa Bay, to...

  16. Lessons Learned from the Bay Region Atmospheric Chemistry Experiment (BRACE) and Implications for Nitrogen Management of Tampa Bay

    EPA Science Inventory

    Results from air quality modeling and field measurements made as part of the Bay Region Atmospheric Chemistry Experiment (BRACE) along with related scientific literature were reviewed to provide an improved estimate of atmospheric reactive nitrogen (N) deposition to Tampa Bay, to...

  17. Control Experiment of Positively Charged Fine Particles at the Atmospheric Pressure

    SciTech Connect

    Yokota, Toshiaki; Ando, Ayumi; Sato, Noriyoshi

    2005-10-31

    It is already reported that the negatively charged fine particle flow was controlled by application of external electric field. The control of positively charged fine particles was examined in this experiment.The fine particles are able to take charges in the air under the atmospheric pressure by irradiation of UV light. The control of the positively charged fine particles has been attempted by the external electric field applied the negative potential. The fine particles for experiments are volcanic ashes, nylon 16, glass, and ice. Experiment was performed in the T-shaped glass chamber under the atmospheric pressure. The halogen lamp (500 W) was used to exit the electrons from particles by photo-emission. The ring and disk electrodes to control the positively charged particles were set at the bottom of chamber. The parallel electrodes were set at the middle of chamber and horizontal static electric fields (E = 0 {approx} 210 V/cm) were created in order to estimate the charge of fine particles. The charges of particle were estimated by the deflection of particle trajectory in the static electric fields and particle velocity. The estimated charges were 104e {approx} 5x106e and 103e {approx} 105e for volcanic ashes and nylon 16, respectively. When positively charged particles were introduced into collecting electrodes, the fine particles are collected in the electrodes. The result of control of positively charged fine particles is shown in this conference.

  18. Mass storage system experiences and future needs at the National Center for Atmospheric Research

    NASA Technical Reports Server (NTRS)

    Olear, Bernard T.

    1991-01-01

    A summary and viewgraphs of a discussion presented at the National Space Science Data Center (NSSDC) Mass Storage Workshop is included. Some of the experiences of the Scientific Computing Division at the National Center for Atmospheric Research (NCAR) dealing the the 'data problem' are discussed. A brief history and a development of some basic mass storage system (MSS) principles are given. An attempt is made to show how these principles apply to the integration of various components into NCAR's MSS. Future MSS needs for future computing environments is discussed.

  19. Titan's atmosphere simulation experiment using a continuous-spectrum UV-VUV synchrotron beamline

    NASA Astrophysics Data System (ADS)

    Peng, Z.; Gautier, T.; Carrasco, N.; Giuliani, A.; Mahjoub, A.; Correia, J.-J.; Pernot, P.; Buch, A.; Bénilan, Y.; Szopa, C.; Cernogora, G.

    2012-09-01

    We report here a new reactor, named APSIS for Atmospheric Photochemistry SImulated by Synchrotron, where a gas mixture (N2/CH4=90/10) at various pressures in the mbar range in the reactor is irradiated using the continuous-spectrum (60-350 nm) DISCO beam in the SOLEIL Radiation Facility. The photochemical products, in situ detected by quadrupole mass spectrometry, include C2, C3, C4 and probably C5 compounds.We compared the neutral productions in APSIS and other experiments with the INMS measurements.

  20. High Temperature, Controlled-Atmosphere Aerodynamic Levitation Experiments with Applications in Planetary Science

    NASA Astrophysics Data System (ADS)

    Macris, C. A.; Badro, J.; Eiler, J. M.; Stolper, E. M.

    2016-12-01

    The aerodynamic levitation laser apparatus is an instrument in which spherical samples are freely floated on top of a stream of gas while being heated with a CO2laser to temperatures up to about 3500 °C. Laser heated samples, ranging in size from 0.5 to 3.5 mm diameter, can be levitated in a variety of chemically active or inert atmospheres in a gas-mixing chamber (e.g., Hennet et al. 2006; Pack et al. 2010). This allows for containerless, controlled-atmosphere, high temperature experiments with potential for applications in earth and planetary science. A relatively new technique, aerodynamic levitation has been used mostly for studies of the physical properties of liquids at high temperatures (Kohara et al. 2011), crystallization behavior of silicates and oxides (Arai et al. 2004), and to prepare glasses from compositions known to crystallize upon quenching (Tangeman et al. 2001). More recently, however, aerodynamic levitation with laser heating has been used as an experimental technique to simulate planetary processes. Pack et al. (2010) used levitation and melting experiments to simulate chondrule formation by using Ar-H2 as the flow gas, thus imposing a reducing atmosphere, resulting in reduction of FeO, Fe2O3, and NiO to metal alloys. Macris et al. (2015) used laser heating with aerodynamic levitation to reproduce the textures and diffusion profiles of major and minor elements observed in impact ejecta from the Australasian strewn field, by melting a powdered natural tektite mixed with 60-100 μm quartz grains on a flow of pure Ar gas. These experiments resulted in quantitative modeling of Si and Al diffusion, which allowed for interpretations regarding the thermal histories of natural tektites and their interactions with the surrounding impact vapor plume. Future experiments will employ gas mixing (CO, CO2, H2, O, Ar) in a controlled atmosphere levitation chamber to explore the range of fO2applicable to melt-forming impacts on other rocky planetary bodies

  1. Atmospheric photochemistry of aromatic hydrocarbons: OH budgets during SAPHIR chamber experiments

    NASA Astrophysics Data System (ADS)

    Nehr, S.; Bohn, B.; Dorn, H.-P.; Fuchs, H.; Häseler, R.; Hofzumahaus, A.; Li, X.; Rohrer, F.; Tillmann, R.; Wahner, A.

    2014-07-01

    Current photochemical models developed to simulate the atmospheric degradation of aromatic hydrocarbons tend to underestimate OH radical concentrations. In order to analyse OH budgets, we performed experiments with benzene, toluene, p-xylene and 1,3,5-trimethylbenzene in the atmosphere simulation chamber SAPHIR. Experiments were conducted under low-NO conditions (typically 0.1-0.2 ppb) and high-NO conditions (typically 7-8 ppb), and starting concentrations of 6-250 ppb of aromatics, dependent on OH rate constants. For the OH budget analysis a steady-state approach was applied in which OH production and destruction rates (POH and DOH) have to be equal. The POH were determined from measurements of HO2, NO, HONO, and O3 concentrations, considering OH formation by photolysis and recycling from HO2. The DOH were calculated from measurements of the OH concentrations and total OH reactivities. The OH budgets were determined from DOH/POH ratios. The accuracy and reproducibility of the approach were assessed in several experiments using CO as a reference compound where an average ratio DOH/POH = 1.13 ± 0.19 was obtained. In experiments with aromatics, these ratios ranged within 1.1-1.6 under low-NO conditions and 0.9-1.2 under high-NO conditions. The results indicate that OH budgets during photo-oxidation experiments with aromatics are balanced within experimental accuracies. Inclusion of a further, recently proposed OH production via HO2 + RO2 reactions led to improvements under low-NO conditions but the differences were small and insignificant within the experimental errors.

  2. Atmospheric photochemistry of aromatic hydrocarbons: OH budgets during SAPHIR chamber experiments

    NASA Astrophysics Data System (ADS)

    Nehr, S.; Bohn, B.; Dorn, H.-P.; Fuchs, H.; Häseler, R.; Hofzumahaus, A.; Li, X.; Rohrer, F.; Tillmann, R.; Wahner, A.

    2014-03-01

    Current photochemical models developed to simulate the atmospheric degradation of aromatic hydrocarbons tend to underestimate OH radical concentrations. In order to analyse OH budgets, we performed experiments with benzene, toluene, p-xylene, and 1,3,5-trimethylbenzene in the atmosphere simulation chamber SAPHIR. Experiments were conducted under low-NO conditions (typically 0.1-0.2 ppb) and high-NO conditions (typically 7-8 ppb), and starting concentrations of 6-250 ppb of aromatics, dependent on OH rate constants. For the OH budget analysis a steady-state approach was applied where OH production and destruction rates (POH and DOH) have to be equal. The POH were determined from measurements of HO2, NO, HONO, and O3 concentrations, considering OH formation by photolysis and recycling from HO2. The DOH were calculated from measurements of the OH concentrations and total OH reactivities. The OH budgets were determined from DOH / POH ratios. The accuracy and reproducibility of the approach were assessed in several experiments using CO as a reference compound where an average ratio DOH / POH = 1.13 ± 0.19 was obtained. In experiments with aromatics, these ratios ranged within 1.1-1.6 under low-NO conditions and 0.9-1.2 under high-NO conditions. The results indicate that OH budgets during photo-oxidation experiments with aromatics are balanced within experimental accuracies. Inclusion of a further, recently proposed OH production via HO2 + RO2 reactions led to improvements under low-NO conditions but the differences were small and insignificant within the experimental errors.

  3. Experiments using atmospheric forcing from a FGGE analysis to drive an upper ocean model

    NASA Technical Reports Server (NTRS)

    Camerlengo, A.

    1983-01-01

    Results are presented of a series of numerical experiments in which an upper ocean model is driven by surface heat fluxes and stress fields derived from the FGGE SOP-1 GLAS analysis/forecast system (Halem, et al., 1982). The model results show that most changes in the mixed layer height and horizontal velocity occurs in the first days. On the other hand, changes in the temperature field take a longer time to develop. In the most realistic case (real initial conditions, instantaneous forcing fields from the atmospheric analysis), the resulting changes in temperature were larger than observed and the correlation between observed and predicted changes was poor. The deficiency in the forecast of SST changes may be due to several factors: lack of sufficient ocean resolution, improper initialization, lack of feedback between the ocean and the atmosphere and the absence of transports by the strong boundary currents, and perhaps unrealistic surface fluxes of heat and momentum. Unless these problems are alleviated it is not reasonable to perform coupled atmospheric ocean forecasts.

  4. GLACE: The Global Land-Atmosphere Coupling Experiment. Part 1; Overview

    NASA Technical Reports Server (NTRS)

    Koster, Randal D.; Guo, Zhi-Chang; Dirmeyer, Paul A.; Bonan, Gordon; Chan, Edmond; Cox, Peter; Davies, Harvey; Gordon, C. T.; Kanae, Shinjiro; Kowalczyk, Eva

    2005-01-01

    GLACE is a model intercomparison study focusing on a typically neglected yet critical element of numerical weather and climate modeling: land-atmosphere coupling strength, or the degree to which anomalies in land surface state (e.g., soil moisture) can affect rainfall generation and other atmospheric processes. The twelve AGCM groups participating in GLACE performed a series of simple numerical experiments that allow the objective quantification of this element. The derived coupling strengths vary widely. Some similarity, however, is found in the spatial patterns generated by the models, enough similarity to pinpoint multi-model "hot spots" of land-atmosphere coupling. For boreal summer, such hot spots for precipitation and temperature are found over large regions of Africa, central North America and India; a hot spot for temperature is also found over eastern China. The design of the GLACE simulations are described in full detail so that any interested modeling group can repeat them easily and thereby place their model s coupling strength within the broad range of those documented here.

  5. Urban Dispersion Modelling and Experiments in the Daytime and Nighttime Atmosphere

    NASA Astrophysics Data System (ADS)

    Franzese, Pasquale; Huq, Pablo

    2011-06-01

    An analytical model of atmospheric dispersion in urban areas in both daytime and nighttime conditions is presented. The model is based on a Gaussian formulation where the horizontal and vertical diffusion coefficients are determined according to analytical theories. The model is validated with dispersion measurements from field experiments conducted in Oklahoma City, Salt Lake City, St. Louis and London, U.K. The theory is in good agreement with the data for both daytime and nighttime conditions. The data support the conclusion that the magnitude of the nighttime stratification in the urban atmosphere is weak; however, its effects on dispersion are not negligible. The predicted existence of two distinct dispersion regimes, in the near and in the far field, is also confirmed by the data. The good collapse of the data suggests that urban dispersion is governed by the characteristic length scales of atmospheric boundary-layer turbulence, rather than urban canopy length scales that are more likely to affect dispersion only in the vicinity of the source.

  6. First Measurements of the HCFC-142b Trend from Atmospheric Chemistry Experiment (ACE) Solar Occultation Spectra

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Chiou, Linda; Boone,Chris; Bernath, Peter; Mahieu, Emmanuel

    2009-01-01

    The first measurement of the HCFC-142b (CH3CClF2) trend near the tropopause has been derived from volume mixing ratio (VMR) measurements at northern and southern hemisphere mid-latitudes for the 2004-2008 time period from spaceborne solar occultation observations recorded at 0.02/cm resolution with the ACE (atmospheric chemistry experiment) Fourier transform spectrometer. The HCFC-142b molecule is currently the third most abundant HCFC (hydrochlorofluorocarbon) in the atmosphere and ACE measurements over this time span show a continuous rise in its volume mixing ratio. Monthly average measurements at northern and southern hemisphere midlatitudes have similar increase rates that are consistent with surface trend measurements for a similar time span. A mean northern hemisphere profile for the time span shows a near constant VMR at 8-20km altitude range, consistent on average for the same time span with in situ results. The nearly constant vertical VMR profile also agrees with model predictions of a long lifetime in the lower atmosphere.

  7. Formation of Amino Acids and Nucleotide Bases in a Titan Atmosphere Simulation Experiment

    PubMed Central

    Yelle, R.V.; Buch, A.; Carrasco, N.; Cernogora, G.; Dutuit, O.; Quirico, E.; Sciamma-O'Brien, E.; Smith, M.A.; Somogyi, Á.; Szopa, C.; Thissen, R.; Vuitton, V.

    2012-01-01

    Abstract The discovery of large (>100 u) molecules in Titan's upper atmosphere has heightened astrobiological interest in this unique satellite. In particular, complex organic aerosols produced in atmospheres containing C, N, O, and H, like that of Titan, could be a source of prebiotic molecules. In this work, aerosols produced in a Titan atmosphere simulation experiment with enhanced CO (N2/CH4/CO gas mixtures of 96.2%/2.0%/1.8% and 93.2%/5.0%/1.8%) were found to contain 18 molecules with molecular formulae that correspond to biological amino acids and nucleotide bases. Very high-resolution mass spectrometry of isotopically labeled samples confirmed that C4H5N3O, C4H4N2O2, C5H6N2O2, C5H5N5, and C6H9N3O2 are produced by chemistry in the simulation chamber. Gas chromatography–mass spectrometry (GC-MS) analyses of the non-isotopic samples confirmed the presence of cytosine (C4H5N3O), uracil (C5H4N2O2), thymine (C5H6N2O2), guanine (C5H5N5O), glycine (C2H5NO2), and alanine (C3H7NO2). Adenine (C5H5N5) was detected by GC-MS in isotopically labeled samples. The remaining prebiotic molecules were detected in unlabeled samples only and may have been affected by contamination in the chamber. These results demonstrate that prebiotic molecules can be formed by the high-energy chemistry similar to that which occurs in planetary upper atmospheres and therefore identifies a new source of prebiotic material, potentially increasing the range of planets where life could begin. Key Words: Astrochemistry—Planetary atmospheres—Titan—Astrobiology. Astrobiology 12, 809–817. PMID:22917035

  8. Formation of amino acids and nucleotide bases in a Titan atmosphere simulation experiment.

    PubMed

    Hörst, S M; Yelle, R V; Buch, A; Carrasco, N; Cernogora, G; Dutuit, O; Quirico, E; Sciamma-O'Brien, E; Smith, M A; Somogyi, A; Szopa, C; Thissen, R; Vuitton, V

    2012-09-01

    The discovery of large (>100 u) molecules in Titan's upper atmosphere has heightened astrobiological interest in this unique satellite. In particular, complex organic aerosols produced in atmospheres containing C, N, O, and H, like that of Titan, could be a source of prebiotic molecules. In this work, aerosols produced in a Titan atmosphere simulation experiment with enhanced CO (N(2)/CH(4)/CO gas mixtures of 96.2%/2.0%/1.8% and 93.2%/5.0%/1.8%) were found to contain 18 molecules with molecular formulae that correspond to biological amino acids and nucleotide bases. Very high-resolution mass spectrometry of isotopically labeled samples confirmed that C(4)H(5)N(3)O, C(4)H(4)N(2)O(2), C(5)H(6)N(2)O(2), C(5)H(5)N(5), and C(6)H(9)N(3)O(2) are produced by chemistry in the simulation chamber. Gas chromatography-mass spectrometry (GC-MS) analyses of the non-isotopic samples confirmed the presence of cytosine (C(4)H(5)N(3)O), uracil (C(5)H(4)N(2)O(2)), thymine (C(5)H(6)N(2)O(2)), guanine (C(5)H(5)N(5)O), glycine (C(2)H(5)NO(2)), and alanine (C(3)H(7)NO(2)). Adenine (C(5)H(5)N(5)) was detected by GC-MS in isotopically labeled samples. The remaining prebiotic molecules were detected in unlabeled samples only and may have been affected by contamination in the chamber. These results demonstrate that prebiotic molecules can be formed by the high-energy chemistry similar to that which occurs in planetary upper atmospheres and therefore identifies a new source of prebiotic material, potentially increasing the range of planets where life could begin.

  9. On the use of plant emitted volatile organic compounds for atmospheric chemistry simulation experiments

    NASA Astrophysics Data System (ADS)

    Kiendler-Scharr, A.; Hohaus, T.; Yu, Z.; Tillmann, R.; Kuhn, U.; Andres, S.; Kaminski, M.; Wegener, R.; Novelli, A.; Fuchs, H.; Wahner, A.

    2015-12-01

    Biogenic volatile organic compounds (BVOC) contribute to about 90% of the emitted VOC globally with isoprene being one of the most abundant BVOC (Guenther 2002). Intensive efforts in studying and understanding the impact of BVOC on atmospheric chemistry were undertaken in the recent years. However many uncertainties remain, e.g. field studies have shown that in wooded areas measured OH reactivity can often not be explained by measured BVOC and their oxidation products (e.g. Noelscher et al. 2012). This discrepancy may be explained by either a lack of understanding of BVOC sources or insufficient understanding of BVOC oxidation mechanisms. Plants emit a complex VOC mixture containing likely many compounds which have not yet been measured or identified (Goldstein and Galbally 2007). A lack of understanding BVOC sources limits bottom-up estimates of secondary products of BVOC oxidation such as SOA. Similarly, the widespread oversimplification of atmospheric chemistry in simulation experiments, using single compound or simple BVOC mixtures to study atmospheric chemistry processes limit our ability to assess air quality and climate impacts of BVOC. We will present applications of the new extension PLUS (PLant chamber Unit for Simulation) to our atmosphere simulation chamber SAPHIR. PLUS is used to produce representative BVOC mixtures from direct plant emissions. We will report on the performance and characterization of the newly developed chamber. As an exemplary application, trees typical of a Boreal forest environment were used to compare OH reactivity as directly measured by LIF to the OH reactivity calculated from BVOC measured by GC-MS and PTRMS. The comparison was performed for both, primary emissions of trees without any influence of oxidizing agents and using different oxidation schemes. For the monoterpene emitters investigated here, we show that discrepancies between measured and calculated total OH reactivity increase with increasing degree of oxidation

  10. Experiments with the Mesoscale Atmospheric Simulation System (MASS) using the synthetic relative humidity

    NASA Technical Reports Server (NTRS)

    Chang, Chia-Bo

    1994-01-01

    This study is intended to examine the impact of the synthetic relative humidity on the model simulation of mesoscale convective storm environment. The synthetic relative humidity is derived from the National Weather Services surface observations, and non-conventional sources including aircraft, radar, and satellite observations. The latter sources provide the mesoscale data of very high spatial and temporal resolution. The synthetic humidity data is used to complement the National Weather Services rawinsonde observations. It is believed that a realistic representation of initial moisture field in a mesoscale model is critical for the model simulation of thunderstorm development, and the formation of non-convective clouds as well as their effects on the surface energy budget. The impact will be investigated based on a real-data case study using the mesoscale atmospheric simulation system developed by Mesoscale Environmental Simulations Operations, Inc. The mesoscale atmospheric simulation system consists of objective analysis and initialization codes, and the coarse-mesh and fine-mesh dynamic prediction models. Both models are a three dimensional, primitive equation model containing the essential moist physics for simulating and forecasting mesoscale convective processes in the atmosphere. The modeling system is currently implemented at the Applied Meteorology Unit, Kennedy Space Center. Two procedures involving the synthetic relative humidity to define the model initial moisture fields are considered. It is proposed to perform several short-range (approximately 6 hours) comparative coarse-mesh simulation experiments with and without the synthetic data. They are aimed at revealing the model sensitivities should allow us both to refine the specification of the observational requirements, and to develop more accurate and efficient objective analysis schemes. The goal is to advance the MASS (Mesoscal Atmospheric Simulation System) modeling expertise so that the model

  11. Do meteoroids of sedimentary origin survive terrestrial atmospheric entry? The ESA artificial meteorite experiment STONE

    NASA Astrophysics Data System (ADS)

    Brack, A.; Baglioni, P.; Borruat, G.; Brandstätter, F.; Demets, R.; Edwards, H. G. M.; Genge, M.; Kurat, G.; Miller, M. F.; Newton, E. M.; Pillinger, C. T.; Roten, C.-A.; Wäsch, E.

    2002-06-01

    The 18 SNC meteorites identified to date are all igneous rocks, being basalts or basaltic cumulates. The lack of sedimentary rocks in this inventory is therefore surprising, in view of the collisional history of Mars and the likelihood that Mars experienced warmer conditions, possibly with a significant hydrosphere, earlier in its history. To address the possibility that sedimentary rocks ejected by impact from the surface of Mars may have reached the Earth, but did not survive terrestrial atmospheric entry, an experiment was performed in which samples of dolomite, a simulated Martian regolith (consisting of basalt fragments in a gypsum matrix) and a basalt were fixed to the heat shield of a recoverable capsule and flown in low Earth orbit. Temperatures attained during re-entry were high enough to melt basalt and the silica fibres of the heat shield and were therefore comparable to those experienced by meteorites. The dolomite sample survived space flight and atmospheric re-entry, in part, as did fragments of the simulated Martian regolith, allowing detailed examinations of these 'artificial meteorites' to be conducted for chemical, mineralogical and isotopic modifications associated with atmospheric re-entry. Oxygen three-isotope measurements of the silica 'fusion crust' formed on the sample holder during atmospheric re-entry fit on a mixing line, with tropospheric O 2 and the interior of the sample holder as end members. Because much of the surface of Mars is covered by clastic sediments, meteorites of Martian provenance might be expected to be mostly sedimentary rocks rather than igneous ones. However, in the absence of a readily identifiable fusion crust, the extraterrestrial origin of such sedimentary rocks on Earth would most probably not be recognised without detailed petrological-geochemical examination and, ultimately, isotope measurements.

  12. Ground-based acoustic parametric generator impact on the atmosphere and ionosphere in an active experiment

    NASA Astrophysics Data System (ADS)

    Rapoport, Yuriy G.; Cheremnykh, Oleg K.; Koshovy, Volodymyr V.; Melnik, Mykola O.; Ivantyshyn, Oleh L.; Nogach, Roman T.; Selivanov, Yuriy A.; Grimalsky, Vladimir V.; Mezentsev, Valentyn P.; Karataeva, Larysa M.; Ivchenko, Vasyl. M.; Milinevsky, Gennadi P.; Fedun, Viktor N.; Tkachenko, Eugen N.

    2017-01-01

    We develop theoretical basics of active experiments with two beams of acoustic waves, radiated by a ground-based sound generator. These beams are transformed into atmospheric acoustic gravity waves (AGWs), which have parameters that enable them to penetrate to the altitudes of the ionospheric E and F regions where they influence the electron concentration of the ionosphere. Acoustic waves are generated by the ground-based parametric sound generator (PSG) at the two close frequencies. The main idea of the experiment is to design the output parameters of the PSG to build a cascade scheme of nonlinear wave frequency downshift transformations to provide the necessary conditions for their vertical propagation and to enable penetration to ionospheric altitudes. The PSG generates sound waves (SWs) with frequencies f1 = 600 and f2 = 625 Hz and large amplitudes (100-420 m s-1). Each of these waves is modulated with the frequency of 0.016 Hz. The novelty of the proposed analytical-numerical model is due to simultaneous accounting for nonlinearity, diffraction, losses, and dispersion and inclusion of the two-stage transformation (1) of the initial acoustic waves to the acoustic wave with the difference frequency Δf = f2 - f1 in the altitude ranges 0-0.1 km, in the strongly nonlinear regime, and (2) of the acoustic wave with the difference frequency to atmospheric acoustic gravity waves with the modulational frequency in the altitude ranges 0.1-20 km, which then reach the altitudes of the ionospheric E and F regions, in a practically linear regime. AGWs, nonlinearly transformed from the sound waves, launched by the two-frequency ground-based sound generator can increase the transparency of the ionosphere for the electromagnetic waves in HF (MHz) and VLF (kHz) ranges. The developed theoretical model can be used for interpreting an active experiment that includes the PSG impact on the atmosphere-ionosphere system, measurements of electromagnetic and acoustic fields, study of

  13. Asian Tracer Experiment and Atmospheric Modeling (TEAM) Project: Draft Field Work Plan for the Asian Long-Range Tracer Experiment

    SciTech Connect

    Allwine, K Jerry; Flaherty, Julia E.

    2007-08-01

    This report provides an experimental plan for a proposed Asian long-range tracer study as part of the international Tracer Experiment and Atmospheric Modeling (TEAM) Project. The TEAM partners are China, Japan, South Korea and the United States. Optimal times of year to conduct the study, meteorological measurements needed, proposed tracer release locations, proposed tracer sampling locations and the proposed durations of tracer releases and subsequent sampling are given. Also given are the activities necessary to prepare for the study and the schedule for completing the preparation activities leading to conducting the actual field operations. This report is intended to provide the TEAM members with the information necessary for planning and conducting the Asian long-range tracer study. The experimental plan is proposed, at this time, to describe the efforts necessary to conduct the Asian long-range tracer study, and the plan will undoubtedly be revised and refined as the planning goes forward over the next year.

  14. Formation of highly oxygenated organic aerosol in the atmosphere: Insights from the Finokalia Aerosol Measurement Experiments

    NASA Astrophysics Data System (ADS)

    Hildebrandt, Lea; Kostenidou, Evangelia; Mihalopoulos, Nikos; Worsnop, Douglas R.; Donahue, Neil M.; Pandis, Spyros N.

    2010-12-01

    Aged organic aerosol (OA) was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiments (FAME-08 and FAME-09), which were part of the EUCAARI intensive campaigns. Quadrupole aerosol mass spectrometers (Q-AMSs) were employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1), and to estimate the extent of oxidation of the OA. The experiments provide unique insights into ambient oxidation of aerosol by measuring at the same site but under different photochemical conditions. NR-PM1 concentrations were about a factor of three lower during FAME-09 (winter) than during FAME-08 (summer). The OA sampled was significantly less oxidized and more variable in composition during the winter than during the early summer. Lower OH concentrations in the winter were the main difference between the two campaigns, suggesting that atmospheric formation of highly oxygenated OA is associated with homogeneous photochemical aging.

  15. Interactions between spacecraft motions and the atmospheric cloud physics laboratory experiments

    NASA Technical Reports Server (NTRS)

    Anderson, B. J.

    1981-01-01

    In evaluating the effects of spacecraft motions on atmospheric cloud physics laboratory (ACPL) experimentation, the motions of concern are those which will result in the movement of the fluid or cloud particles within the experiment chambers. Of the various vehicle motions and residual forces which can and will occur, three types appear most likely to damage the experimental results: non-steady rotations through a large angle, long-duration accelerations in a constant direction, and vibrations. During the ACPL ice crystal growth experiments, the crystals are suspended near the end of a long fiber (20 cm long by 200 micron diameter) of glass or similar material. Small vibrations of the supported end of the fiber could cause extensive motions of the ice crystal, if care is not taken to avoid this problem.

  16. The possibility to observe the non-standard interaction by the Hyperkamiokande atmospheric neutrino experiment

    NASA Astrophysics Data System (ADS)

    Fukasawa, Shinya; Yasuda, Osamu

    2017-01-01

    It was suggested that a tension between the mass-squared differences obtained from the solar neutrino and KamLAND experiments can be solved by introducing the non-standard flavor-dependent interaction in neutrino propagation. In this paper we discuss the possibility to test such a hypothesis by atmospheric neutrino observations at the future Hyper-Kamiokande experiment. Assuming that the mass hierarchy is known, we find that the best-fit value from the solar neutrino and KamLAND data can be tested at more than 8σ, while the one from the global analysis can be examined at 5.0σ (1.4σ) for the normal (inverted) mass hierarchy.

  17. The effect of the atmospheric condition on the extensive air shower analysis at the Telescope Array experiment

    SciTech Connect

    Kobayashi, Y.; Tsunesada, Y.; Tokuno, H.; Kakimoto, F.; Tomida, T.

    2011-09-22

    The accuracies in determination of air shower parameters such as longitudinal profiles or primary energies with the fluorescence detection technique are strongly dependent on atmospheric conditions of the molecular and aerosol components. Moreover, air fluorescence photon yield depends on the atmospheric density, and the transparency of the air for fluorescence photons depends on the atmospheric conditions from EAS to FDs. In this paper, we describe the atmospheric monitoring system in the Telescope Array (TA experiment), and the impact of the atmospheric conditions in air shower reconstructions. The systematic uncertainties of the determination of the primary cosmic ray energies and of the measurement of depth of maximum development (X{sub max}) of EASs due to atmospheric variance are evaluated by Monte Carlo simulation.

  18. Large Eddy Simulation and Field Experiments of Pollen Transport in the Atmospheric Boundary Layer

    NASA Astrophysics Data System (ADS)

    Chamecki, M.; Meneveau, C.; Parlange, M. B.; van Hout, R.

    2006-12-01

    Dispersion of airborne pollen by the wind has been a subject of interest for botanists and allergists for a long time. More recently, the development of genetically modified crops and questions about cross-pollination and subsequent contamination of natural plant populations has brought even more interest to this field. A critical question is how far from the source field pollen grains will be advected. Clearly the answer depends on the aerodynamic properties of the pollen, geometrical properties of the field, topography, local vegetation, wind conditions, atmospheric stability, etc. As a consequence, field experiments are well suited to provide some information on pollen transport mechanisms but are limited to specific field and weather conditions. Numerical simulations do not have this drawback and can be a useful tool to study pollen dispersal in a variety of configurations. It is well known that the dispersion of particles in turbulent fields is strongly affected by the large scale coherent structures. Large Eddy Simulation (LES) is a technique that allows us to study the typical distances reached by pollen grains and, at the same time, resolve the larger coherent structures present in the atmospheric boundary layer. The main objective of this work is to simulate the dispersal of pollen grains in the atmospheric surface layer using LES. Pollen concentrations are simulated by an advection-diffusion equation including gravitational settling. Of extreme importance is the specification of the bottom boundary conditions characterizing the pollen source over the canopy and the deposition process everywhere else. In both cases we make use of the theoretical profile for suspended particles derived by Kind (1992). Field experiments were performed to study the applicability of the theoretical profile to pollen grains and the results are encouraging. Airborne concentrations as well as ground deposition from the simulations are compared to experimental data to validate the

  19. The atmospheric neutral density experiment (ANDE) and modulating retroreflector in space (MODRAS): combined flight experiments for the space test program

    NASA Astrophysics Data System (ADS)

    Nicholas, Andrew C.; Gilbreath, G. Charmaine; Thonnard, Stefan E.; Kessel, R. A.; Lucke, Robert; Sillman, C. P.

    2003-03-01

    The Atmospheric Neutral Density Experiment (ANDE) is a low cost mission proposed by the Naval Research Laboratory to demonstrate a method to monitor the thermospheric neutral density at an altitude of 400 km. The primary mission objective is to provide total neutral density along the orbit for improved orbit determination of resident space objects. The ANDE mission also serves as a test platform for a new space-to-ground optical communications technique, the Modulating Retro-reflector Array in Space (MODRAS) experiment. Both are sponsored in part by the Department of Defense Space Test Program. The mission consists of two spherical spacecraft fitted with retro-reflectors for satellite laser ranging (SLR). One spacecraft is completely passive; the other carries three active instruments; a miniature Wind And Temperature Spectrometer (WATS) to measure atmospheric composition, cross-track winds and neutral temperature; a Global Positioning Sensor (GPS); and a Thermal Monitoring System (TMS) to monitor the temperature of the sphere. A design requirement of the active satellite is to telemeter the data to the ground without external protrusions from the spherical spacecraft (i.e. an antenna). The active satellite will be fitted with the MODRAS system, which is an enabling technology for the ANDE mission. The MODRAS system consists of a set of multiple quantum well (MQW) modulating retro-reflectors coupled with an electronics package, which will telemeter data to the ground by modulating the reflected light from laser interrogation beam. This paper presents a mission overview and emphasis will be placed on the design, optical layout, performance, ground station, and science capabilities of the combined missions.

  20. Observing system simulation experiments for the laser atmospheric wind sounder using global spectral model

    NASA Technical Reports Server (NTRS)

    Rohaly, Gregg; Krishnamurti, T. N.

    1991-01-01

    Fundamental to improving the understanding of the total Earth system are increased and improved observations. In the coming decade several spaceborne instrumented platforms will be constructed and implemented. These platforms will, in large, be housing the NASA Earth Observing System (EOS) instrument suite. One of the proposed instruments is a wind profiling system which is currently referred to as the Laser Atmospheric Wind Sounder (LAWS). This instrument will use a CO2 Doppler lidar wind profiler to give wind measurements with a vertical and horizontal resolution which has yet to be seen globally. The LAWS instrument is now a candidate for launch on a NASA EOS-B platform and is fundamental to increasing our understanding of Earth system science. The LAWS data sets will form an integral component of the temporally continuous data base needed for research of the coupled climate systems. This instrument's observations will aid in giving an improved description of the atmospheric circulation, including the transports of energy, momentum, moisture, trace gases, and aerosols. Also, the wind data will be assimilated and used as the initial state for many global forecast models at various operational centers. Results of system simulation experiments are discussed, and future experiments are described.

  1. Insights Into Atmospheric Aqueous Organic Chemistry Through Controlled Experiments with Cloud Water Surrogates

    NASA Astrophysics Data System (ADS)

    Turpin, B. J.; Ramos, A.; Kirkland, J. R.; Lim, Y. B.; Seitzinger, S.

    2011-12-01

    There is considerable laboratory and field-based evidence that chemical processing in clouds and wet aerosols alters organic composition and contributes to the formation of secondary organic aerosol (SOA). Single-compound laboratory experiments have played an important role in developing aqueous-phase chemical mechanisms that aid prediction of SOA formation through multiphase chemistry. In this work we conduct similar experiments with cloud/fog water surrogates, to 1) evaluate to what extent the previously studied chemistry is observed in these more realistic atmospheric waters, and 2) to identify additional atmospherically-relevant precursors and products that require further study. We used filtered Camden and Pinelands, NJ rainwater as a surrogate for cloud water. OH radical (~10-12 M) was formed by photolysis of hydrogen peroxide and samples were analyzed in real-time by electrospray ionization mass spectroscopy (ESI-MS). Discrete samples were also analyzed by ion chromatography (IC) and ESI-MS after IC separation. All experiments were performed in duplicate. Standards of glyoxal, methylglyoxal and glycolaldehyde and their major aqueous oxidation products were also analyzed, and control experiments performed. Decreases in the ion abundance of many positive mode compounds and increases in the ion abundance of many negative mode compounds (e.g., organic acids) suggest that precursors are predominantly aldehydes, organic peroxides and/or alcohols. Real-time ESI mass spectra were consistent with the expected loss of methylglyoxal and subsequent formation of pyruvate, glyoxylate, and oxalate. New insights regarding other potential precursors and products will be provided.

  2. Particulate polycyclic aromatic hydrocarbons in the Atlantic and Indian Ocean atmospheres during the Indian Ocean Experiment and Aerosols99: Continental sources to the marine atmosphere

    NASA Astrophysics Data System (ADS)

    Crimmins, Bernard S.; Dickerson, Russell R.; Doddridge, Bruce G.; Baker, Joel E.

    2004-03-01

    Polycyclic aromatic hydrocarbons (PAHs), mutagenic compounds predominantly derived from combustion, have been used as markers of combustion sources to the atmosphere. Marine aerosol collected aboard the NOAA R/V Ronald Brown during the Aerosols99 and the Indian Ocean Experiment (INDOEX) projects was analyzed for PAHs to assess the continental impact of combustion-derived particulate matter on the Atlantic and Indian Ocean atmospheres. PAH concentrations in the Atlantic and southern Indian Ocean atmospheres were consistent and low, ranging from <0.45 pg/m3 for coronene to 30 pg/m3 for 9, 10-dimethylanthracene. PAH concentrations increased ten fold as the ship crossed the Intertropical Convergence Zone (ITCZ) into the northern Indian Ocean, indicating an increased anthropogenic influence. PAH concentrations over the northern Indian Ocean atmosphere were approximately an order of magnitude greater than those in the northern Atlantic Ocean atmosphere. PAH composition profiles over the northern Indian Ocean were specific to wind regimes and influenced by a combination of biomass and fossil fuel combustion. This was supported by significant correlations between select PAHs and organic carbon (OC), elemental carbon (EC), SO4-2 and K+ for particular wind regimes. Indeno[1,2,3-cd]pyrene/EC ratios used as a combustion source marker suggest that fossil fuel combustion, rather than biomass burning, is the predominant source of PAHs to the Northern Hemisphere Indian Ocean atmosphere. Interestingly, fossil fuel consumption in the Indian sub-continent is a fraction of that in Europe and the United States but the soot and PAH levels in the adjacent Northern Indian Ocean atmosphere are significantly greater than those in the Northern Atlantic atmosphere.

  3. Validation of stratospheric ozone observed by the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment during 1992

    NASA Technical Reports Server (NTRS)

    Abrams, M. C.; Gunson, M. R.; Chang, A. Y.; Rinsland, C. P.; Zander, R.; Newchurch, M. H.

    1995-01-01

    Measurements of stratospheric ozone were made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment from onboard the Space Shuttle during the period 8-16 April 1992. The precision and accuracy of the measurements are discussed in the context of establishing the accuracy and compatibility of the measurements relative to other space-based measurements of ozone. Coincident measurements were obtained from the Stratospheric Aerosol and Gas Experiment (SAGE) 2 instrument onboard the Earth Radiation Budget Satellite (ERBS) and three instruments, the Microwave Limb Sounder (MLS), the Cryogenic Limb Array Etalon Spectrometer (CLAES), the Halogen Occultation Experiment (HALOE) onboard the Upper Atmospheric Research Satellite (UARS). Three of the instruments, ATMOS, SAGE-2 and MLS are demonstrated to be consistent to within +10% over the altitude range between 100 hPa and 0.5 hPa (approximately 20 to 60 km), with ATMOS and MLS displaying a zero mean bias and a root mean square deviation (rms) of 3% and SAGE-2 displaying an essentially systematic bias of -5% over the majority of the altitude range, except for below 30 hPa where SAGE-2 displays a large positive systematic bias due to the effect of the aerosol attenuation resulting from the Mt. Pinatubo volcanic eruption in 1991. The comparison with HALOE indicates that ozone levels observed by ATMOS are systematically higher than HALOE by 5 to 25% with a clear gradient in the differences; in contrast the comparison with CLAES displays differences of as much as + 30% with no obvious systematic scaling possible. Comparisons are evaluated in two separate schemes, by geographical coincidence and through zonal averages which illustrate the limitations of both schemes. Latitudinal and longitudinal variation are used to assess the sensitivity of the ATMOS measurements and to confirm the precision and accuracy, which should be less than 4% and 10% respectively.

  4. A global high-resolution model experiment on the predictability of the atmosphere

    NASA Astrophysics Data System (ADS)

    Judt, F.

    2016-12-01

    Forecasting high-impact weather phenomena is one of the most important aspects of numerical weather prediction (NWP). Over the last couple of years, a tremendous increase in computing power has facilitated the advent of global convection-resolving NWP models, which allow for the seamless prediction of weather from local to planetary scales. Unfortunately, the predictability of specific meteorological phenomena in these models is not very well known. This raises questions about which forecast problems are potentially tractable, and what is the value of global convection-resolving model predictions for the end user. To address this issue, we use the Yellowstone supercomputer to conduct a global high-resolution predictability experiment with the recently developed Model for Prediction Across Scales (MPAS). The computing power of Yellowstone enables the model to run at a globally uniform resolution of 4 km with 55 vertical levels (>2 billion grid cells). These simulations, which require 3 million core-hours for the entire experiment, allow for the explicit treatment of organized deep moist convection (i.e., thunderstorm systems). Resolving organized deep moist convection alleviates grave limitations of previous predictability studies, which either used high-resolution limited-area models or global simulations with coarser grids and cumulus parameterization. By computing the error growth characteristics in a set of "identical twin" model runs, the experiment will clarify the intrinsic predictability limits of atmospheric phenomena on a wide range of scales, from severe thunderstorms to global-scale wind patterns that affect the distribution of tropical rainfall. Although a major task by itself, this study is intended to be exploratory work for a future predictability experiment going beyond of what has so far been feasible. We hope to use CISL's new Cheyenne supercomputer to conduct a similar predictability experiments on a global mesh with 1-2 km resolution. This

  5. Laboratory Simulations Of Titan’s Atmospheric Chemistry With The NASA Ames Titan Haze Simulation Experiment

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, Ella; Contreras, C. S.; Ricketts, C. L.; Salama, F.

    2012-05-01

    Solar UV radiation and electron bombardment from Saturn’s magnetosphere dissociate nitrogen and methane in Titan’s atmosphere, leading to the production of heavier molecules and solid organic aerosols that contribute to the haze layers giving Titan its characteristic orange color. The detection of benzene and toluene, critical precursors of polycyclic aromatic hydrocarbon (PAH), in Titan’s ionosphere, by the Cassini INMS suggests that PAHs might play a role in the production of Titan’s aerosols. The Titan Haze Simulation (THS) experiment has been developed at NASA Ames’ Cosmic Simulation facility (COSmIC) to study the chemical pathways that link the simple molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN..) to benzene, and to PAHs and nitrogen-containing PAHs (PANHs) as precursors to the production of solid aerosols. In the THS experiment, Titan’s atmospheric chemistry is simulated by plasma in the stream of a supersonic jet expansion. With this unique design, the gas mixture is cooled to Titan-like temperature ( 150K) before inducing the chemistry by plasma discharge. Different gas mixtures containing the first products of Titan’s N2-CH4 chemistry, but also much heavier molecules like PAHs or PANHs can be injected to study specific chemical reactions. The products of the chemistry are detected and studied using Cavity Ring Down Spectroscopy and Time-Of-Flight Mass Spectrometry. Thin tholin (Titan aerosol analogs) deposits are also produced in the THS experiment and can be analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and Scanning Electron Microscopy (SEM). We present the results of mass spectrometry studies using different gas mixtures, and discuss their relevance for the study of specific pathways in Titan’s atmospheric chemistry. Acknowledgements: This research is supported by NASA PATM. E.S.O., C.S.C. and C.L.R acknowledge the support of the NASA Postdoctoral Program. The authors acknowledge the

  6. Atmospheric PCDD/F measurement in Taiwan and Southeast Asia during Dongsha Experiment

    NASA Astrophysics Data System (ADS)

    Thuan, Ngo Thi; Chi, Kai Hsien; Wang, Sheng-Hsiang; Chang, Moo Been; Lin, Neng-Huei; Sheu, Guey-Rong; Peng, Chi-Ming

    2013-10-01

    The international campaign of Dongsha Experiment was conducted in the northern Southeast Asian region during March-May 2010. To address the effects of long-range transport on the persistent organic pollutants and further understand the PCDD/F contamination in Vietnam, atmospheric PCDD/Fs were evaluated at a coastal station (Pingtung County, Sites A) in southern Taiwan, remote island station in South China Sea (Dongsha Island, Site B) and coastal station (Da Nang City, Site C) in central Vietnam during different sampling periods in this study. The measurements indicated that the atmospheric PCDD/F concentrations were 1.01-27.4 fg I-TEQ/m3 (n = 22), 1.52-10.8 fg I-TEQ/m3 (n = 17) and 23.4-146 fg I-TEQ/m3 (n = 16) at Sites A, B and C, respectively, during different periods in 2010. In March 2010, an Asian dust storm (ADS) that originated in Gobi deserts eventually reached populated areas of East Asia, including Taiwan and the island in northern South China Sea. During the ADS episode, measurements made in southern Taiwan and South China Sea on 16 and 21 March 2010 indicate that the atmospheric PCDD/F concentration increased 6.5 and 6.9 times at Sites A and B, respectively. Furthermore, the significantly higher PCDD/F concentrations and contents in suspended particles (134-546 pg I-TEQ/g-TSP) were measured at Site C in the central Vietnam. In addition, the distribution of PCDD/F congeners measured in Central Vietnam was quite different from those measured at other stations with high PCDD distribution (>80%) especially in OCDD (>70%). During the Vietnam conflict, United States (US) forces had sprayed a greater volume of defoliant with higher PCDD/F contents than originally estimated. We consider that the high fraction of PCDDs observed in Vietnam probably originated as anthropogenic emission from specific source in Vietnam.

  7. Experience with novel technologies for direct measurement of atmospheric NO2

    NASA Astrophysics Data System (ADS)

    Hueglin, Christoph; Hundt, Morten; Mueller, Michael; Schwarzenbach, Beat; Tuzson, Bela; Emmenegger, Lukas

    2017-04-01

    Nitrogen dioxide (NO2) is an air pollutant that has a large impact on human health and ecosystems, and it plays a key role in the formation of ozone and secondary particulate matter. Consequently, legal limit values for NO2 are set in the EU and elsewhere, and atmospheric observation networks typically include NO2 in their measurement programmes. Atmospheric NO2 is principally measured by chemiluminescence detection, an indirect measurement technique that requires conversion of NO2 into nitrogen monoxide (NO) and finally calculation of NO2 from the difference between total nitrogen oxides (NOx) and NO. Consequently, NO2 measurements with the chemiluminescence method have a relatively high measurement uncertainty and can be biased depending on the selectivity of the applied NO2 conversion method. In the past years, technologies for direct and selective measurement of NO2 have become available, e.g. cavity attenuated phase shift spectroscopy (CAPS), cavity enhanced laser absorption spectroscopy and quantum cascade laser absorption spectrometry (QCLAS). These technologies offer clear advantages over the indirect chemiluminescence method. We tested the above mentioned direct measurement techniques for NO2 over extended time periods at atmospheric measurement stations and report on our experience including comparisons with co-located chemiluminescence instruments equipped with molybdenum as well as photolytic NO2 converters. A still open issue related to the direct measurement of NO2 is instrument calibration. Accurate and traceable reference standards and NO2 calibration gases are needed. We present results from the application of different calibration strategies based on the use of static NO2 calibration gases as well as dynamic NO2 calibration gases produced by permeation and by gas-phase titration (GPT).

  8. Low-cost and easy experiments about water in the atmosphere

    NASA Astrophysics Data System (ADS)

    Costa, M.; Mazon, J.

    2012-04-01

    Atmospheric water represents only the 0,001% of the total water in the hydrosphere. Despite this tiny percentage, the physical changes water experiences in the atmosphere are essential for the conservation of this substance in our planet. Often, the understanding of the presence of water in the Earth's atmosphere and its physical changes inside this gas layer are difficult for most secondary and primary school students. We present 5 examples of simple practical activities that will facilitate students to think about and understand some important concepts about atmospheric water. Two of the basic principles to bear in mind when designing these activities are the use of cheap and easy to find materials and the simplicity of the construction and development of each activity. This simplicity makes it possible for the students to easily carry the experiments in the classroom or in the laboratory, using only a part of a class session. We think that the use of these kinds of activities enables us to work some basic concepts about atmospheric water with the students which lead to a more meaningful understanding, not only of these concepts but also of many other processes related to this part of the hydrosphere, such as meteorological phenomena, erosion, floods, etc. Here we present a brief description of the five experiments we suggest: 1- a crazy thermometer? Using water at the same temperature of the air, a piece of paper and two thermometers, we can easily "build" a dry and a wet bulb thermometer. Making questions about the differences between the temperatures of both thermometers we can understand what the air's humidity is and how we can calculate it. 2- what are clouds made of? Most of people think that clouds are made of water vapour. Observing what happens with the air above a small container filled with warm water when we approach a tray containing ice, we can conduct a Socratic dialogue that allows us to understand that clouds are made of ice or liquid water

  9. Search for dark matter annihilation in Draco with the Solar Tower Atmospheric Cherenkov Effect Experiment

    SciTech Connect

    Driscoll, D. D.; Covault, C. E.; Ball, J.; Carson, J. E.; Jarvis, A.; Ong, R. A.; Zweerink, J.; Hanna, D. S.; Kildea, J.; Lindner, T.; Mueller, C.; Ragan, K.; Fortin, P.; Mukherjee, R.; Williams, D. A.; Gingrich, D. M.

    2008-10-15

    For some time, the Draco dwarf spheroidal galaxy has garnered interest as a possible source for the indirect detection of dark matter. Its large mass-to-light ratio and relative proximity to the Earth provide favorable conditions for the production of a detectable flux of gamma rays from dark matter self-annihilation in its core. The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is an atmospheric Cherenkov telescope located in Albuquerque, NM capable of detecting gamma rays at energies above 100 GeV. We present the results of the STACEE observations of Draco during the 2005-2006 observing season totaling 10.2 hours of live time after cuts. We do not detect a significant gamma-ray signal from Draco, and place an upper limit on a power-law spectrum of (dN/dE)|{sub Draco}<1.6x10{sup -13}((E/220 GeV)){sup -2.2}{gamma} s{sup -1} cm{sup -2} GeV{sup -1} Assuming a smooth Navarro-Frenk-White profile for the dark-matter halo and an annihilation spectrum, we also derive upper limits for the cross-section-velocity product (<{sigma}v>) for weakly interacting massive particles self-annihilation.

  10. Improved VAS regression soundings of mesoscale temperature structure observed during the 1982 atmospheric variability experiment

    NASA Technical Reports Server (NTRS)

    Chesters, Dennis; Keyser, Dennis A.; Larko, David E.; Uccellini, Louis W.

    1987-01-01

    An Atmospheric Variability Experiment (AVE) was conducted over the central U.S. in the spring of 1982, collecting radiosonde date to verify mesoscale soundings from the VISSR Atmospheric Sounder (VAS) on the GOES satellite. Previously published VAS/AVE comparisons for the 6 March 1982 case found that the satellite retrievals scarcely detected a low level temperature inversion or a mid-tropospheric cold pool over a special mesoscale radiosonde verification network in north central Texas. The previously published regression and physical retrieval algorithms did not fully utilize VAS' sensitivity to important subsynoptic thermal features. Therefore, the 6 March 1982 case was reprocessed adding two enhancements to the VAS regression retrieval algorithm: (1) the regression matrix was determined using AVE profile data obtained in the region at asynoptic times, and (2) more optimistic signal-to-noise statistical conditioning factors were applied to the VAS temperature sounding channels. The new VAS soundings resolve more of the low level temperature inversion and mid-level cold pool. Most of the improvements stems from the utilization of asynoptic radiosonde observations at NWS sites. This case suggests that VAS regression soundings may require a ground-based asynoptic profiler network to bridge the gap between the synoptic radiosonde network and the high resolution geosynchronous satellite observations during the day.

  11. Radiometric correction of atmospheric path length fluctuations in interferometric experiments. [in radio astronomy

    NASA Technical Reports Server (NTRS)

    Resch, G. M.; Hogg, D. E.; Napier, P. J.

    1984-01-01

    To support very long baseline interferometric experiments, a system has been developed for estimating atmospheric water vapor path delay. The system consists of dual microwave radiometers, one operating at 20.7 GHz and the other at 31.4 GHz. The measured atmospheric brightness temperatures at these two frequencies yield the estimate of the precipitable water present in both vapor and droplets. To determine the accuracy of the system, a series of observations were undertaken, comparing the outputs of two water vapor radiometers with the phase variation observed with two connected elements of the very large array (VLA). The results show that: (1) water vapor fluctuations dominate the residual VLA phase and (2) the microwave radiometers can measure and correct these effects. The rms phase error after correction is typically 15 deg at a wavelength of 6 cm, corresponding to an uncertainty in the path delay of 0.25 cm. The residual uncertainty is consistent with the stability of the microwave radiometer but is still considerably larger than the stability of the VLA. The technique is less successful under conditions of heavy cloud.

  12. Materials performance in the atmospheric fluidized-bed cogeneration air heater experiment

    SciTech Connect

    Natesan, K.; Podolski, W.; Wang, D.Y.; Teats, F.G.; Gerritsen, W.; Stewart, A.; Robinson, K.

    1991-02-01

    The Atmospheric Fluidized-Bed Cogeneration Air Heater Experiment (ACAHE) sponsored by the US Department of Energy (DOE) was initiated to assess the performance of various heat-exchanger materials to be used in fluidized-bed combustion air heater systems. Westinghouse Electric Corporation, through subcontracts with Babcock & Wilcox, Foster Wheeler, and ABB Combustion Engineering Systems, prepared specifications and hardware for the ACAHE tests. Argonne National Laboratory contracted with Rockwell International to conduct tests in the DOE atmospheric fluidized-bed combustion facility. This report presents an overview of the project, a description of the facility and the test hardware, the test operating conditions, a summary of the operation, and the results of analyzing specimens from several uncooled and cooled probes exposed in the facility. Extensive microstructural analyses of the base alloys, claddings, coatings, and weldments were performed on specimens exposed in several probes for different lengths of time. Alloy penetration data were determined for several of the materials as a function of specimen orientation and the exposure location in the combustor. Finally, the data were compared with earlier laboratory test data, and the long-term performance of candidate materials for air-heater applications was assessed.

  13. Fast time resolution oxidized mercury measurements during the Reno Atmospheric Mercury Intercomparison Experiment (RAMIX).

    PubMed

    Ambrose, Jesse L; Lyman, Seth N; Huang, Jiaoyan; Gustin, Mae S; Jaffe, Daniel A

    2013-07-02

    The Reno Atmospheric Mercury Intercomparison Experiment (RAMIX) was carried out from 22 August to 16 September, 2011 in Reno, NV to evaluate the performance of new and existing methods to measure atmospheric mercury (Hg). Measurements were made using a common sampling manifold to which controlled concentrations of Hg species, including gaseous elemental mercury (GEM) and HgBr2 (a surrogate gaseous oxidized mercury (GOM) compound), and potential interferents were added. We present an analysis of Hg measurements made using the University of Washington's Detector for Oxidized Hg Species (DOHGS), focusing on tests of GEM and HgBr2 spike recovery, the potential for interference from ozone (O3) and water vapor (WV), and temporal variability of ambient reactive mercury (RM). The mean GEM and HgBr2 spike recoveries measured with the DOHGS were 95% and 66%, respectively. The DOHGS responded linearly to HgBr2. We found no evidence that elevated O3 interfered in the DOHGS RM measurements. A reduction in RM collection and retention efficiencies at very high ambient WV mixing ratios is possible. Comparisons between the DOHGS and participating Hg instruments demonstrate good agreement for GEM and large discrepancies for RM. The results suggest that existing GOM measurements are biased low.

  14. Radiometric correction of atmospheric path length fluctuations in interferometric experiments. [in radio astronomy

    NASA Technical Reports Server (NTRS)

    Resch, G. M.; Hogg, D. E.; Napier, P. J.

    1984-01-01

    To support very long baseline interferometric experiments, a system has been developed for estimating atmospheric water vapor path delay. The system consists of dual microwave radiometers, one operating at 20.7 GHz and the other at 31.4 GHz. The measured atmospheric brightness temperatures at these two frequencies yield the estimate of the precipitable water present in both vapor and droplets. To determine the accuracy of the system, a series of observations were undertaken, comparing the outputs of two water vapor radiometers with the phase variation observed with two connected elements of the very large array (VLA). The results show that: (1) water vapor fluctuations dominate the residual VLA phase and (2) the microwave radiometers can measure and correct these effects. The rms phase error after correction is typically 15 deg at a wavelength of 6 cm, corresponding to an uncertainty in the path delay of 0.25 cm. The residual uncertainty is consistent with the stability of the microwave radiometer but is still considerably larger than the stability of the VLA. The technique is less successful under conditions of heavy cloud.

  15. Materials performance in the atmospheric fluidized-bed cogeneration air heater experiment

    SciTech Connect

    Natesan, K.; Podolski, W.; Wang, D.Y.; Teats, F.G. ); Gerritsen, W.; Stewart, A.; Robinson, K. )

    1991-02-01

    The Atmospheric Fluidized-Bed Cogeneration Air Heater Experiment (ACAHE) sponsored by the US Department of Energy (DOE) was initiated to assess the performance of various heat-exchanger materials to be used in fluidized-bed combustion air heater systems. Westinghouse Electric Corporation, through subcontracts with Babcock Wilcox, Foster Wheeler, and ABB Combustion Engineering Systems, prepared specifications and hardware for the ACAHE tests. Argonne National Laboratory contracted with Rockwell International to conduct tests in the DOE atmospheric fluidized-bed combustion facility. This report presents an overview of the project, a description of the facility and the test hardware, the test operating conditions, a summary of the operation, and the results of analyzing specimens from several uncooled and cooled probes exposed in the facility. Extensive microstructural analyses of the base alloys, claddings, coatings, and weldments were performed on specimens exposed in several probes for different lengths of time. Alloy penetration data were determined for several of the materials as a function of specimen orientation and the exposure location in the combustor. Finally, the data were compared with earlier laboratory test data, and the long-term performance of candidate materials for air-heater applications was assessed.

  16. A Long-term Forest Fertilization Experiment to Understand Ecosystem Responses to Atmospheric Nitrogen Deposition

    NASA Astrophysics Data System (ADS)

    Baron, J.; Advani, S. M.; Allen, J.; Boot, C.; Denef, K.; Denning, S.; Hall, E.; Moore, J. C.; Reuth, H.; Ryan, M. G.; Shaw, E.

    2016-12-01

    Long-term field experiments can reveal changes in ecosystem processes that may not be evident in short-term studies. Short-term measurements or experiments may have narrower objectives or unrealistic treatments in order to see a change, whereas long-term studies can reveal complex interactions that take longer to manifest. We report results from a long-term experiment (1996 to present) in subalpine forests to simulate the consequences of sustained atmospheric nitrogen (N) deposition. Loch Vale watershed in Rocky Mountain National Park, the location of the experiment, has received an order of magnitude greater atmospheric N deposition than estimated background since mid-20th Century. Augmenting that, in 1996 we began adding 25 kg NH4NO3 ha-1 yr-1 to three 30m x 30m old-growth Engelmann spruce and subalpine fir plots. Treated stands were matched by nearby controls. N addition caused rapid leaching of nitrate and cations from soils, and increased N mineralization and nitrification rates. These observations in the fertilized plots have been sustained over time. Soluble aluminum concentrations do not differ significantly between fertilized and control plots, but treated soils are now markedly more acidic (pH of 4.7) than original soil and controls (pH of 5.1); further acidification might increase aluminum leaching. Effects on soil carbon were complex, mediated by reductions in total microbial biomass, decreases in arbuscular mychorrizal and saprotropic fungi, and increased potential rates of N enzyme degrading activities. Initial soil C:N of 24 was lower than similar soils in low N deposition stands (C:N of 36). The C:N declined to 22 with treatment. Fertilized plots lost 11% soil C, but the mechanism is unclear. We did not measure changes in C inputs from litter, microbial biomass, or plant uptake, but there was no change in summer CO2 flux, measured in 2003, 2004, and 2014. Leaching of DOC from fertilized plots was elevated throughout the experiment, providing one

  17. Theoretical and experimental design studies for the Atmospheric General Circulation Experiment

    NASA Technical Reports Server (NTRS)

    Fowlis, W. W.; Hathaway, D. H.; Miller, T. L.; Roberts, G. O.; Kopecky, K. J.

    1985-01-01

    The major criterion for the Atmospheric General Circulation Experiment (AGCE) design is that it be possible to realize strong baroclinic instability in the spherical configuration chosen. A configuration was selected in which a hemispherical shell of fluid is subjected to latitudinal temperature gradients on its spherical boundaries and the latitudinal boundaries are insulators. Work in the laboratory with a cylindrical version of this configuration revealed more instabilities than baroclinic instability. Since researchers fully expect these additional instabilities to appear in the spherical configuration also, they decided to continue the laboratory cylindrical annulus studies. Four flow regimes were identified: an axisymmetric Hadley circulation, boundary layer convection, baroclinic waves and deep thermal convection. Regime diagrams were prepared.

  18. The Second Phase of the Global Land-Atmosphere Coupling Experiment (GLACE-2)

    NASA Technical Reports Server (NTRS)

    Koster, Randal D.; Yamada, T.; Mahanama, S.; Guo, Z.; Dirmeyer, P. A.; VandenHurk, B. J. J. M.

    2010-01-01

    A major motivation for the study of the coupled land-atmosphere system is the idea that soil moisture anomalies may affect future meteorological variables through their effects on future surface energy and water budgets. If true, the accurate initialization of soil moisture in a subseasonal or seasonal forecast system may improve forecast skill, making the forecast products more valuable to society. The GLACE-2 project is examining, through a coordinated experiment using a wide variety of models, the degree to which subseasonal (out to two months) precipitation and air temperature forecasts improve through the realistic initialization of soil moisture. For the first time ever, a global consensus should emerge regarding the value of land initialization for forecasts, perhaps motivating national forecast centers to make full use of land moisture initialization in their operations

  19. Stable Atmospheric Boundary-Layer Experiment in Spain (SABLES 98): A Report

    NASA Astrophysics Data System (ADS)

    Cuxart, J.; Yague, C.; Morales, G.; Terradellas, E.; Orbe, J.; Calvo, J.; Fernandez, A.; Soler, M.R.; Infante, C.; Buenestado, P.; Espinalt, A.; Joergensen, H.E.; Rees, J.M.; Vila, J.; Redondo, J.M.; Cantalapiedra, I.R.; Conangla, L.

    This paper describes the Stable AtmosphericBoundary Layer Experiment in Spain (SABLES 98),which took place over the northern Spanish plateaucomprising relatively flat grassland,in September 1998. The main objectives of the campaign were to study the properties of themid-latitude stable boundary layer (SBL).Instrumentation deployed on two meteorologicalmasts (of heights 10 m and 100 m)included five sonic anemometers, 15 thermocouples,five cup anemometers and three propeller anemometers,humidity sensors and radiometers.A Sensitron mini-sodar and a tetheredballoon were also operated continuously. Atriangular array of cup anemometers wasinstalled to allow the detection ofwave events. Two nocturnal periods analysedon 14-15 and 20-21 September are used toillustrate the wide-ranging characteristics of the SBL.

  20. Mass wasting triggered by seasonal CO2 sublimation under Martian atmospheric conditions: Laboratory experiments

    NASA Astrophysics Data System (ADS)

    Sylvest, Matthew E.; Conway, Susan J.; Patel, Manish R.; Dixon, John C.; Barnes, Adam

    2016-12-01

    Sublimation is a recognized process by which planetary landscapes can be modified. However, interpretation of whether sublimation is involved in downslope movements on Mars and other bodies is restricted by a lack of empirical data to constrain this mechanism of sediment transport and its influence on landform morphology. Here we present the first set of laboratory experiments under Martian atmospheric conditions which demonstrate that the sublimation of CO2 ice from within the sediment body can trigger failure of unconsolidated, regolith slopes and can measurably alter the landscape. Previous theoretical studies required CO2 slab ice for movements, but we find that only frost is required. Hence, sediment transport by CO2 sublimation could be more widely applicable (in space and time) on Mars than previously thought. This supports recent work suggesting CO2 sublimation could be responsible for recent modification in Martian gullies.

  1. Two-dimensional atmospheric transport and chemistry model - Numerical experiments with a new advection algorithm

    NASA Technical Reports Server (NTRS)

    Shia, Run-Lie; Ha, Yuk Lung; Wen, Jun-Shan; Yung, Yuk L.

    1990-01-01

    Extensive testing of the advective scheme proposed by Prather (1986) has been carried out in support of the California Institute of Technology-Jet Propulsion Laboratory two-dimensional model of the middle atmosphere. The original scheme is generalized to include higher-order moments. In addition, it is shown how well the scheme works in the presence of chemistry as well as eddy diffusion. Six types of numerical experiments including simple clock motion and pure advection in two dimensions have been investigated in detail. By comparison with analytic solutions, it is shown that the new algorithm can faithfully preserve concentration profiles, has essentially no numerical diffusion, and is superior to a typical fourth-order finite difference scheme.

  2. Two-dimensional atmospheric transport and chemistry model - Numerical experiments with a new advection algorithm

    NASA Technical Reports Server (NTRS)

    Shia, Run-Lie; Ha, Yuk Lung; Wen, Jun-Shan; Yung, Yuk L.

    1990-01-01

    Extensive testing of the advective scheme proposed by Prather (1986) has been carried out in support of the California Institute of Technology-Jet Propulsion Laboratory two-dimensional model of the middle atmosphere. The original scheme is generalized to include higher-order moments. In addition, it is shown how well the scheme works in the presence of chemistry as well as eddy diffusion. Six types of numerical experiments including simple clock motion and pure advection in two dimensions have been investigated in detail. By comparison with analytic solutions, it is shown that the new algorithm can faithfully preserve concentration profiles, has essentially no numerical diffusion, and is superior to a typical fourth-order finite difference scheme.

  3. Solar/Stellar Irradiance Comparison Experiment (SOLSTICE) on the Upper Atmosphere Research Satellite (UARS)

    NASA Technical Reports Server (NTRS)

    Rottman, Gary J.; Woods, Thomas N.; London, Julius; Ayres, Thomas R.

    2003-01-01

    A final report on the operational activities related to the UARS Solar Stellar irradiance Comparison Experiment (SOLSTICE) is presented. Scientific activities of SOLSTICE has also been supported. The UARS SOLSTICE originated at the University of Colorado in 1981. One year after the UARS launch in 1991, the operations and research support activities for SOLSTICE were moved to the High Altitude Observatory (HAO) of the National Center for Atmospheric Research (NCAR). The SOLSTICE program continued at HAO with the National Science Foundation, and after four years, it was moved once again back to the University of Colorado. At the University after 1997 this subject grant was issued to further extend the operations activities from July 2001 through September 2002. Although this is a final report for one particular activity, in fact the SOLSTICE operations activity -first at the University, then at HAO, and now again at the University -has continued in a seamless fashion.

  4. The Second Phase of the Global Land-Atmosphere Coupling Experiment (GLACE-2)

    NASA Technical Reports Server (NTRS)

    Koster, Randal D.; Yamada, T.; Mahanama, S.; Guo, Z.; Dirmeyer, P. A.; VandenHurk, B. J. J. M.

    2010-01-01

    A major motivation for the study of the coupled land-atmosphere system is the idea that soil moisture anomalies may affect future meteorological variables through their effects on future surface energy and water budgets. If true, the accurate initialization of soil moisture in a subseasonal or seasonal forecast system may improve forecast skill, making the forecast products more valuable to society. The GLACE-2 project is examining, through a coordinated experiment using a wide variety of models, the degree to which subseasonal (out to two months) precipitation and air temperature forecasts improve through the realistic initialization of soil moisture. For the first time ever, a global consensus should emerge regarding the value of land initialization for forecasts, perhaps motivating national forecast centers to make full use of land moisture initialization in their operations

  5. Chamber experiments to investigate the release of fungal IN into the atmosphere

    NASA Astrophysics Data System (ADS)

    Kunert, Anna Theresa; Krüger, Mira; Scheel, Jan Frederik; Helleis, Frank; Pöschl, Ulrich; Fröhlich-Nowoisky, Janine

    2015-04-01

    Biological aerosol particles are ubiquitous in the atmosphere. Several types of microorganisms like bacteria, fungi and lichen have been identified as sources of biological ice nuclei (IN). They are a potentially strong source of atmospheric IN, as some of them are able to catalyze ice formation at relatively warm subfreezing temperatures. Common plant-associated bacteria are the best-known biological IN but recently ice nucleation activity in a variety of fungal species such as Mortierella alpina, Isaria farinosa, Acremonium implicatum was found. These fungal species are widely spread throughout the world and are present in soil and air. Their IN seem to be proteins, which are not anchored in the fungal cell wall. To which extent these small, cell-free IN are emitted directly into the atmosphere remains unexplored just as other processes, which probably indirectly release fungal IN e.g. absorbed onto soil dust particles. To analyze the release of fungal IN into the air, we designed a chamber, whose main principle is based on the emission of particles into a closed gas compartment and the subsequent collection of these particles in water. The concentration of the collected IN in the water is determined by droplet freezing assays. For a proof of principles, fungal washing water containing cell-free IN was atomized by an aerosol generator and the produced gas stream was lead through a water trap filled with pure water. Preliminary results show a successful proof of principles. The chamber design is capable of collecting aerosolic IN produced by an aerosol generator with fungal washing water. In ongoing experiments, alive or dead fungal cultures are placed into the chamber and a gentle, particle free air stream is directed over the fungi surface. This gas stream is also lead through water to collect particles, which might be emitted either actively or passively by the fungi. Further experiments will be e.g. conducted under different relative humidities. Results

  6. Mineralogical alteration of artificial meteorites during atmospheric entry. The STONE-5 experiment

    NASA Astrophysics Data System (ADS)

    Brandstätter, Franz; Brack, André; Baglioni, Pietro; Cockell, Charles S.; Demets, René; Edwards, Howell G. M.; Kurat, Gero; Osinski, Gordon R.; Pillinger, Judith M.; Roten, Claude-Alain; Sancisi-Frey, Suzy

    2008-05-01

    The generic concept of the artificial meteorite experiment STONE is to fix rock samples bearing microorganisms on the heat shield of a recoverable space capsule and to study their modifications during atmospheric re-entry. The STONE-5 experiment was performed mainly to answer astrobiological questions. The rock samples mounted on the heat shield were used (i) as a carrier for microorganisms and (ii) as internal control to verify whether physical conditions during atmospheric re-entry were comparable to those experienced by "real" meteorites. Samples of dolerite (an igneous rock), sandstone (a sedimentary rock), and gneiss impactite from Haughton Crater carrying endolithic cyanobacteria were fixed to the heat shield of the unmanned recoverable capsule FOTON-M2. Holes drilled on the back side of each rock sample were loaded with bacterial and fungal spores and with dried vegetative cryptoendoliths. The front of the gneissic sample was also soaked with cryptoendoliths. The mineralogical differences between pre- and post-flight samples are detailed. Despite intense ablation resulting in deeply eroded samples, all rocks in part survived atmospheric re-entry. Temperatures attained during re-entry were high enough to melt dolerite, silica, and the gneiss impactite sample. The formation of fusion crusts in STONE-5 was a real novelty and strengthens the link with real meteorites. The exposed part of the dolerite is covered by a fusion crust consisting of silicate glass formed from the rock sample with an admixture of holder material (silica). Compositionally, the fusion crust varies from silica-rich areas (undissolved silica fibres of the holder material) to areas whose composition is "basaltic". Likewise, the fusion crust on the exposed gneiss surface was formed from gneiss with an admixture of holder material. The corresponding composition of the fusion crust varies from silica-rich areas to areas with "gneiss" composition (main component potassium-rich feldspar). The

  7. Education Relative a l'Environnement: Regards, Recherches, Reflexions. Volume 1.

    ERIC Educational Resources Information Center

    1999

    This document reports the work of an inter-university colloquium in Montreal in November, 1997 on research on the evaluation of education relative to the environment. Papers include: (1) "Un "patrimoine" de recherche en construction" (Lucie Sauve); (2) "Pour une recherche en education relative l'environnement "centree sur l'objet partage"" (Louis…

  8. Education Relative a l'Environnement: Regards, Recherches, Reflexions. Volume 1.

    ERIC Educational Resources Information Center

    1999

    This document reports the work of an inter-university colloquium in Montreal in November, 1997 on research on the evaluation of education relative to the environment. Papers include: (1) "Un "patrimoine" de recherche en construction" (Lucie Sauve); (2) "Pour une recherche en education relative l'environnement "centree sur l'objet partage"" (Louis…

  9. Design of experiments on a DC Steady State Atmospheric Pressure Plasma Sterilizer

    NASA Astrophysics Data System (ADS)

    Alexeff, Igor; Balasundaram, Arun; Sawheny, Rapinder

    2009-11-01

    Our Resistive Barrier Discharge has been demonstrated to be successful on E. coli, Pseudomonas fluorescens (5RL), spores and bacteriophages. It has been tested successfully in sterilizing pagers at the St. Jude Research Hospital in Memphis, TN. In this recent work, we evaluate three primary factors in the atmospheric pressure resistive barrier discharge, hydrogen peroxide, charged ions and air (oxygen). The experiment used was Analysis of Variance (ANOVA) and regression analysis. The tests used 144 Petri Dishes and the bacteria used were E. coli. The hydrogen peroxide was used as a replacement for the water conductor on the resistive barrier discharge electrode. The charged ions were removed by a double charged wire mesh between the discharge and the Petri Dish. The air was displaced by a slow flow of nitrogen into the experimental area. The basic conclusions are that air, and charged ions are both extremely effective in killing bacteria. In addition, air and charged ions together strongly enhance each other. Hydrogen peroxide in our experiments did not enhance the kill rate.

  10. Comparison between the atmospheric boundary layer in Paris and its rural suburbs during the ECLAP experiment

    NASA Astrophysics Data System (ADS)

    Dupont, E.; Menut, L.; Carissimo, B.; Pelon, J.; Flamant, P.

    The ECLAP experiment has been performed during the winter of 1995 in order to study the influence of the urban area of Paris on the vertical structure and diurnal evolution of the atmospheric boundary layer, in situations favourable to intense urban heat island and pollution increase. One urban site and one rural site have been instrumented with sodars, lidars and surface measurements. Additional radiosondes, 100 m masts and Eiffel Tower data were also collected. This paper gives a general overview of this experiment, and presents results of the analysis of four selected days, characterized by various wind directions and temperature inversion strengths. This analysis, which consists in a comparison between data obtained in the two sites, has been focused on three parameters of importance to the ABL dynamics: the standard deviation of vertical velocity, the surface sensible heat flux, and the boundary layer height. The vertical component of turbulence is shown to be enhanced by the urban area, the amplitude of this effect strongly depending on the meteorological situation. The sensible heat flux in Paris is generally found larger than in the rural suburbs. The most frequent differences range from 25-65 W m -2, corresponding to relative differences of 20-60%. The difference of unstable boundary layer height between both sites are most of the time less than 100 m. However, sodar and temperature data show that the urban influence is enhanced during night-time and transitions between stable and unstable regimes.

  11. Use of halophytes to remove carbon from the atmosphere: Results of a demonstration experiment. Final report

    SciTech Connect

    Glenn, E.; Olsen, M.; Frye, R.; Moore, D.

    1994-01-01

    The project examined the feasibility of using salt-tolerant plants, halophytes, to sequester large quantities of C from the atmosphere and enhance food production in desert regions of the world by using seawater and other saline water sources for irrigation. Field experiments using 40 ppt seawater in a coastal desert site in Mexico recorded biomass yields of 16.7--34.0 t ha{sup {minus}1} yr{sup {minus}1} and C yields of 5.4--10.1 t ha{sup {minus}1} yr{sup {minus}1}for the best candidate species in the genera Atriplex, Batis, Salicornia, Suaeda and Sesuvium. These yields are comparable to high-yielding forestry and agricultural biomass crops. Irrigation requirements and other costs of production were within the range of conventional crops as well. Laboratory and field experiments showed that seawater had an inhibitory effect on the decomposition of halophyte biomass in soil; hence, a strategy for C sequestration in desert soil was proposed, in which halophyte crop by-products would be returned to the soil to store C while the harvested portions would be used for oilseeds and animal feed.

  12. The Titan Haze Simulation experiment: laboratory simulation of Titan's atmospheric chemistry at low temperature

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, E.; Contreras, C. S.; Ricketts, C. L.; Salama, F.

    2012-04-01

    In Titan’s atmosphere, a complex organic chemistry between its two main constituents, N2 and CH4, leads to the production of heavy molecules and subsequently to solid organic aerosols. Several instruments onboard Cassini have detected neutral, positively and negatively charged particles and heavy molecules in the ionosphere of Titan[1,2]. In particular, the presence of benzene (C6H6) and toluene (C6H5CH3)[3], which are critical precursors of polycyclic aromatic hydrocarbon (PAH) compounds, suggests that PAHs might play a role in the production of Titan’s aerosols. The Titan Haze Simulation (THS) experiment has been developed at NASA Ames’ Cosmic Simulation facility (COSmIC) to study the chemical pathways that link the simple precursor molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN…) to benzene, and to PAHs and nitrogen-containing PAHs (or PANHs) as precursors to the production of solid aerosols. In the THS experiment, Titan’s atmospheric chemistry is simulated by plasma in the stream of a supersonic jet expansion. With this unique design, the gas mixture is cooled to Titan-like temperature (~150K) before inducing the chemistry by plasma discharge. Different gas mixtures containing the first products of Titan’s N2-CH4 chemistry but also much heavier molecules like PAHs or PANHs can be injected to study specific chemical reactions. The products of the chemistry are detected and studied using two complementary techniques: Cavity Ring Down Spectroscopy[4] and Time-Of-Flight Mass Spectrometry[5]. Thin tholin deposits are also produced in the THS experiment and can be analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and Scanning Electron Microscopy (SEM). We will present the results of ongoing mass spectrometry studies on the THS experiment using different gas mixtures: N2-CH4, N2-C2H2, N2-C2H4, N2-C2H6, N2-C6H6, and similar mixtures with an N2-CH4 (90:10) mixture instead of pure N2, to study specific pathways

  13. CalWater 2 - Precipitation, Aerosols, and Pacific Atmospheric Rivers Experiment

    NASA Astrophysics Data System (ADS)

    Spackman, J. R.; Ralph, F. M.; Prather, K. A.; Cayan, D. R.; DeMott, P. J.; Dettinger, M. D.; Fairall, C. W.; Leung, L. R.; Rosenfeld, D.; Rutledge, S. A.; Waliser, D. E.; White, A. B.

    2014-12-01

    Emerging research has identified two phenomena that play key roles in the variability of the water supply and the incidence of extreme precipitation events along the West Coast of the United States. These phenomena include the role of (1) atmospheric rivers (ARs) in delivering much of the precipitation associated with major storms along the U.S. West Coast, and (2) aerosols—from local sources as well as those transported from remote continents—and their modulating effects on western U.S. precipitation. A better understanding of these processes is needed to reduce uncertainties in weather predictions and climate projections of extreme precipitation and its effects, including the provision of beneficial water supply. This presentation summarizes the science objectives and strategies to address gaps associated with (1) the evolution and structure of ARs including cloud and precipitation processes and air-sea interaction, and (2) aerosol interaction with ARs and the impact on precipitation, including locally-generated aerosol effects on orographic precipitation along the U.S. West Coast. Observations are proposed for multiple winter seasons as part of a 5-year broad interagency vision referred to as CalWater 2 to address these science gaps (http://esrl.noaa.gov/psd/calwater). In January-February 2015, a field campaign has been planned consisting of a targeted set of aircraft and ship-based measurements and associated evaluation of data in near-shore regions of California and in the eastern Pacific. In close coordination with NOAA, DOE's Atmospheric Radiation Measurement (ARM) program is also contributing air and shipborne facilities for ACAPEX (ARM Cloud Aerosol and Precipitation Experiment), a DOE-sponsored study complementing CalWater 2. Ground-based measurements from NOAA's HydroMeteorological Testbed (HMT) network in California and aerosol chemical instrumentation at Bodega Bay, California have been designed to add important near surface-level context for the

  14. Response of atmospheric blocks to the Arctic Amplification in idealized model experiments

    NASA Astrophysics Data System (ADS)

    Yoo, Yeong-Eun; Son, Seok-Woo

    2016-04-01

    Atmospheric block is the abnormal quasi-stationary system which obstructs the weather system flow in the midlatitude. Because of its importance on extreme weather, its long-term trend in response to the Arctic amplification has been extensively examined. While several studies have documented a hint of increasing blocking frequency due to the Arctic amplification, others have shown essentially no evidence of such change. The present study re-visits this issue by performing a series of idealized model experiments. A primitive equation model is integrated using Held and Suarez (1994) temperature forcing. Specifically, the equator-to-pole temperature difference (ΔT) is systematically reduced from 100K to 60K with a 10-K interval by mimicking Arctic amplification. Blocks are then identified by applying the hybrid blocking index, which incorporates blocking anomaly and absolute gradient reversal, to 500-hPa geopotential height fields. With decreasing ΔT (e.g., Arctic-amplification-like state), westerly jet becomes weaker and moves equatorward. Likewise, both high- and low-frequency eddies get weaker and shift equatorward along the jet. Blocks, which primarily form on the poleward flank of the jet, also shift equatorward. Atmospheric block, which is quasi-stationary system, tends to occur more frequently as weather systems move slowly. However, blocked area becomes smaller, indicating that less frequent blocks tend to have a larger spatial scale. In the presence of wavenumber-1 topography, this relationship breaks down. Both number and area of blocks tend to decrease with decreasing ΔT. This result indicates that stationary wave plays an important in modulating blocks. More importantly, it supports the previous studies that documented no evidence of block change in response to the Arctic amplification.

  15. The THS Experiment: Simulating Titans Atmospheric Chemistry at Low Temperature (200K)

    NASA Technical Reports Server (NTRS)

    Sciamma-O'Brien, Ella; Upton, Kathleen; Beauchamp, Jack L.; Salama, Farid; Contreras, Cesar Sanchez; Bejaoui, Salma; Foing, Bernard; Pascale, Ehrenfreund

    2015-01-01

    In Titan's atmosphere, composed mainly of N2 (95-98%) and CH4 (2-5%), a complex chemistry occurs at low temperature, and leads to the production of heavy organic molecules and subsequently solid aerosols. Here, we used the Titan Haze Simulation (THS) experiment, an experimental setup developed at the NASA Ames COSmIC simulation facility to study Titan's atmospheric chemistry at low temperature. In the THS, the chemistry is simulated by plasma in the stream of a supersonic expansion. With this unique design, the gas is cooled to Titan-like temperature ( approximately 150K) before inducing the chemistry by plasma, and remains at low temperature in the plasma discharge (approximately 200K). Different N2-CH4-based gas mixtures can be injected in the plasma, with or without the addition of heavier precursors present as trace elements on Titan, in order to monitor the evolution of the chemical growth. Both the gas- and solid phase products resulting from the plasma-induced chemistry can be monitored and analyzed using a combination of complementary in situ and ex situ diagnostics. A recent mass spectrometry[1] study of the gas phase has demonstrated that the THS is a unique tool to probe the first and intermediate steps of Titan's atmospheric chemistry at Titan-like temperature. In particular, the mass spectra obtained in a N2-CH4-C2H2-C6H6 mixture are relevant for comparison to Cassini's CAPS-IBS instrument. The results of a complementary study of the solid phase are consistent with the chemical growth evolution observed in the gas phase. Grains and aggregates form in the gas phase and can be jet deposited on various substrates for ex situ analysis. Scanning Electron Microscopy images show that more complex mixtures produce larger aggregates. A mass spectrometry analysis of the solid phase has detected the presence of aminoacetonitrile, a precursor of glycine, in the THS aerosols. X-ray Absorption Near Edge Structure (XANES) measurements also show the presence of imine

  16. CO2 Dissociation using the Versatile Atmospheric Dielectric Barrier Discharge Experiment (VADER)

    NASA Astrophysics Data System (ADS)

    Lindon, Michael Allen

    As of 2013, the Carbon Dioxide Information Analysis Center (CDIAC) estimates that the world emits approximately 36 trillion metric tons of Carbon Dioxide (CO2) into the atmosphere every year. These large emissions have been correlated to global warming trends that have many consequences across the globe, including glacial retraction, ocean acidification and increased severity of weather events. With green technologies still in the infancy stage, it can be expected that CO2 emissions will stay this way for along time to come. Approximately 41% of the emissions are due to electricity production, which pump out condensed forms of CO2. This danger to our world is why research towards new and innovative ways of controlling CO2 emissions from these large sources is necessary. As of now, research is focused on two primary methods of CO2 reduction from condensed CO2 emission sources (like fossil fuel power plants): Carbon Capture and Sequestration (CCS) and Carbon Capture and Utilization (CCU). CCS is the process of collecting CO2 using absorbers or chemicals, extracting the gas from those absorbers and finally pumping the gas into reservoirs. CCU on the other hand, is the process of reacting CO2 to form value added chemicals, which can then be recycled or stored chemically. A Dielectric Barrier discharge (DBD) is a pulsed, low temperature, non-thermal, atmospheric pressure plasma which creates high energy electrons suitable for dissociating CO2 into its components (CO and O) as one step in the CCU process. Here I discuss the viability of using a DBD for CO2 dissociation on an industrial scale as well as the fundamental physics and chemistry of a DBD for CO2 dissociation. This work involved modeling the DBD discharge and chemistry, which showed that there are specific chemical pathways and plasma parameters that can be adjusted to improve the CO2 reaction efficiencies and rates. Experimental studies using the Versatile Atmospheric dielectric barrier Discharge ExpeRiment

  17. Zero-Gravity Atmospheric Cloud Physics Experiment Laboratory engineering concepts/design tradeoffs. Volume 1: Study results

    NASA Technical Reports Server (NTRS)

    Greco, R. V.; Eaton, L. R.; Wilkinson, H. C.

    1974-01-01

    The work is summarized which was accomplished from January 1974 to October 1974 for the Zero-Gravity Atmospheric Cloud Physics Laboratory. The definition and development of an atmospheric cloud physics laboratory and the selection and delineation of candidate experiments that require the unique environment of zero gravity or near zero gravity are reported. The experiment program and the laboratory concept for a Spacelab payload to perform cloud microphysics research are defined. This multimission laboratory is planned to be available to the entire scientific community to utilize in furthering the basic understanding of cloud microphysical processes and phenomenon, thereby contributing to improved weather prediction and ultimately to provide beneficial weather control and modification.

  18. Atmospheric monitoring of a perfluorocarbon tracer at the 2009 ZERT Center experiment

    NASA Astrophysics Data System (ADS)

    Pekney, Natalie; Wells, Arthur; Rodney Diehl, J.; McNeil, Matthew; Lesko, Natalie; Armstrong, James; Ference, Robert

    2012-02-01

    Field experiments at Montana State University are conducted for the U.S. Department of Energy as part of the Zero Emissions Research and Technology Center (ZERT) to test and verify monitoring techniques for carbon capture and storage (CCS). A controlled release of CO 2 with an added perfluorocarbon tracer was conducted in July 2009 in a multi-laboratory study of atmospheric transport and detection technologies. Tracer plume dispersion was measured with various meteorological conditions using a tethered balloon system with Multi-Tube Remote Samplers (MTRS) at elevations of 10 m, 20 m, and 40 m above ground level (AGL), as well as a ground-based portable tower with monitors containing sorbent material to collect the tracer at 1 m, 2 m, 3 m, and 4 m AGL. Researchers designed a horizontal grid of sampling locations centered at the tracer plume source, with the tower positioned at 10 m and 30 m in both upwind and downwind directions, and the MTRS spaced at 50 m and 90 m downwind and 90 m upwind. Tracer was consistently detected at elevated concentrations at downwind sampling locations. With very few exceptions, higher tracer concentrations correlated with lower elevations. Researchers observed no statistical difference between sampling at 50 m and 90 m downwind at the same elevation. The US EPA AERMOD model applied using site-specific information predicted transport and dispersion of the tracer. Model results are compared to experimental data from the 2009 ZERT experiment. Successful characterization of the tracer plume simulated by the ZERT experiment is considered a step toward demonstrating the feasibility of remote sampling with unmanned aerial systems (UAS's) at future sequestration sites.

  19. New experience in atmospheric monitoring in Moscow city on the base of WSN technology

    NASA Astrophysics Data System (ADS)

    Asavin, Alex; Litvinov, Artur; Baskakov, Sergey; Chesalova, Elena

    2016-04-01

    for each sensors. We use triggers to modify data, for example, to modify signal from gas sensors to gas concentration, in depend of unique sensor name. Additional table gives geographical coordinates of each node. We use GIS project for visualization and data analysis. Experiences revealed the inverse relationship between H2 concentration and temperature and pressure. Also we revealed periodicity of gas concentration with different harmonics. We could not find in literatures the similar works of H2 monitoring in cites. Exclusion is the work of (Necki et al., 2014) to organize continue monitoring in Krakow and it neighborhood. Authors also note periodicity in gas concentration affected by the seasons (increase in wintertime), day time (auto traffic). The received data we consider as first experiments in organization of long time monitoring of cites atmosphere, using new technologies (WSN). This results we consider to be the first methodological experiments in the field of monitoring the atmosphere of the city by WSN technic. It is planned to update the correctness of the analysis based on a comparison with other gas analysis methods. Acknowledgements This study was supported by the program 44 presidium RAS "Search basic research for the development of the Russian Arctic" Reference Necki, Jaroslaw M.; Chmura, Lukasz; Bielewski, Jaroslaw; et al. Variability of Molecular Hydrogen in the Urban Atmosphere Based on Continuous Measurements in Krakow //Polish Journal of Environmental Studies 2014, V.23, Iss. 2, P. 427-434.

  20. First results from the GPS atmospheric remote sensing experiment TOR aboard TerraSAR-X

    NASA Astrophysics Data System (ADS)

    Beyerle, G.; Grunwaldt, L.; Heise, S.; Köhler, W.; Schmidt, T.; Choi, K.-R.; Michalak, G.; König, R.; Rothacher, M.; Wickert, J.

    2009-04-01

    The TerraSAR-X satellite was launched on 15 June 2007 into a sun-synchronous orbit at an altitude of about 514 km and about 98 ° orbit inclination. In addition to synthetic aperture radar and laser communication payloads, TerraSAR-X accommodates the Tracking, Occultation and Ranging (TOR) experiment. TOR's hardware consists of the Integrated Geodetic and Occultation Receiver (IGOR) and a laser retro-reflector for Satellite Laser Ranging (SLR). IGOR, a dual frequency, geodetic-grade GPS receiver instrument, provides signal-to-noise ratios, pseudorange and carrier phase observations of an occulting and a reference satellite at sampling rates of up to 50 Hz for remote sensing of atmospheric refractivity using the radio occultation (RO) technique. For precise orbit determination pseudorange and carrier phase data from all satellites in view are sampled at 0.1 Hz. Three brief RO tests were conducted with TOR in 2007; a 32-day campaign was performed in January/February 2008 and from 25 July to 17 November 2008 occultation events were recorded continuously for 117 days. We describe first results from an analysis of about 19.000 setting radio occultation events observed during that last campaign. Atmospheric refractivity profiles derived from TOR data are intercompared with ECMWF analyses; ECMWF analysis data are interpolated to the time and location of the RO measurement. At altitudes of about 2-25 km the mean fractional refractivity bias with respect to ECMWF is less than ±0.5%, its standard deviation varies between 0.5% and 1% in the altitude range 5-20 km increasing to about 2% at altitudes below 5 km and above 20 km. Unlike the RO receivers aboard the CHAMP and GRACE satellites the IGOR aboard TerraSAR-X employs an open-loop tracking technique to improve L1 carrier phase tracking at altitudes below 5 to 6 km. Consistent with earlier findings from the COSMIC constellation, open-loop tracking significantly reduces the 50%-altitude, the tangent point altitude which is

  1. Improved VAS regression soundings of mesoscale temperature features observed during the atmospheric variability experiment on 6 March 1982. [VISSR Atmospheric Sounder

    NASA Technical Reports Server (NTRS)

    Chesters, Dennis; Keyser, Dennis A.; Larko, David E.; Uccellini, Louis W.

    1988-01-01

    In 1982, the VISSR Atmospheric Sounder (VAS) on the GOES satellite performed the Atmospheric Variability Experiment (AVE) to verify VAS's mesoscale-sounding capabilities. Attention is given to the AVE network in the late afternoon of March 6, 1982, after a winter storm had passed over Texas, in order to ascertain whether such temperature profile deviations from the average lapse rate as a midlevel cold pool (which should decrease the brightness of several IR channels) can be retrieved from VAS radiances. Two simple enhancements are introduced: the regression matrix is calculated using the AVE asynoptic radiosondes launched from NWS sites in the region, and a change of the statistical conditioning factor from the conservative 10/1 SNR to a more optimistic 100/1 for those VAS channels that are more sensitive to tropospheric temperature.

  2. Nanosecond Repetitively Pulsed Discharges in Air at Atmospheric Pressure -- Experiment and Theory of Regime Transitions

    NASA Astrophysics Data System (ADS)

    Pai, David; Lacoste, Deanna; Laux, Christophe

    2009-10-01

    In atmospheric pressure air preheated from 300 to 1000 K, the Nanosecond Repetitively Pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and inter-electrode gap distance) of each discharge regime. Notably, there is a minimum gap distance for the existence of the glow regime that increases with decreasing gas temperature. A theory is developed to describe the Corona-to-Glow (C-G) and Glow-to-Spark (G-S) transitions for NRP discharges. The C-G transition is shown to depend on the Avalanche-to-Streamer Transition (AST) as well as the electric field strength in the positive column. The G-S transition is due to the thermal ionization instability. The minimum gap distance for the existence of the glow regime can be understood by considering that the applied voltage of the AST must be lower than that of the thermal ionization instability. This is a previously unknown criterion for generating glow discharges, as it does not correspond to the Paschen minimum or to the Meek-Raether criterion.

  3. Development of the Lidar Atmospheric Sensing Experiment (LASE): An Advanced Airborne DIAL Instrument

    NASA Technical Reports Server (NTRS)

    Moore, Alvah S., Jr.; Brown, Kevin E.; Hall, William M.; Barnes, James C.; Edwards, William C.; Petway, Larry B.; Little, Alan D.; Luck, William S., Jr.; Jones, Irby W.; Antill, Charles W., Jr.

    1997-01-01

    The Lidar Atmospheric Sensing Experiment (LASE) Instrument is the first fully-engineered, autonomous Differential Absorption Lidar (DIAL) System for the measurement of water vapor in the troposphere (aerosol and cloud measurements are included). LASE uses a double-pulsed Ti:Sapphire laser for the transmitter with a 30 ns pulse length and 150 mJ/pulse. The laser beam is "seeded" to operate on a selected water vapor absorption line in the 815-nm region using a laser diode and an onboard absorption reference cell. A 40 cm diameter telescope collects the backscattered signals and directs them onto two detectors. LASE collects DIAL data at 5 Hz while onboard a NASA/Ames ER-2 aircraft flying at altitudes from 16-21 km. LASE was designed to operate autonomously within the environment and physical constraints of the ER-2 aircraft and to make water vapor profile measurements across the troposphere to better than 10% accuracy. LASE has flown 19 times during the development of the instrument and the validation of the science data. This paper describes the design, operation, and reliability of the LASE Instrument.

  4. Atmospheric, Ionospheric, Surface and Radio Propagation Studies With The Venus Express Radio Science Experiment Vera.

    NASA Astrophysics Data System (ADS)

    Häusler, B.; Pätzold, M.; Bird, M. K.; Treumann, R. A.; Simpson, R. A.; Hinson, D.

    The Venus Radio Science experiment (VeRa) onboard the proposed Venus Express Orbiter will make use of the spacecraft radio carrier signals at X/S-band and an ultrastable oscillator reference frequency source (USO, Allan deviation 10 ­13 ) integrated into the onboard transponder system. VeRa will perform : radio sounding of the Venusian ionosphere from 80 km up to the ionopause (300km to 600 km), radio sounding of the neutral atmosphere from the cloud deck (35km to 40 km) to 100 km altitude, measurements of dielectric properties and roughness of the Venusian surface, studies of the propagation of radio waves in the inner solar system at superior and inferior solar conjunctions. We shall discuss the experimental methods (spacecraft occultation and bistatic radar) and conclude on the achievable accuracies and sensitivities. We shall indicate where improvements in comparison to the Pioneer Venus observations can be expected and examine VeRa`s contribution to the understanding of plasmaphysical processes in the solar wind and planetary ionospheric environment. Effects of the solar coronal plasma and the gravitational field of the Sun on the observables (Doppler, group delay) will also be addressed.

  5. Measurements of Humidity in the Atmosphere and Validation Experiments (Mohave, Mohave II): Results Overview

    NASA Technical Reports Server (NTRS)

    Leblanc, Thierry; McDermid, Iain S.; McGee, Thomas G.; Twigg, Laurence W.; Sumnicht, Grant K.; Whiteman, David N.; Rush, Kurt D.; Cadirola, Martin P.; Venable, Demetrius D.; Connell, R.; Demoz, Belay B.; Vomel, Holger; Miloshevich, L.

    2008-01-01

    The Measurements of Humidity in the Atmosphere and Validation Experiments (MOHAVE, MOHAVE-II) inter-comparison campaigns took place at the Jet Propulsion Laboratory (JPL) Table Mountain Facility (TMF, 34.5(sup o)N) in October 2006 and 2007 respectively. Both campaigns aimed at evaluating the capability of three Raman lidars for the measurement of water vapor in the upper troposphere and lower stratosphere (UT/LS). During each campaign, more than 200 hours of lidar measurements were compared to balloon borne measurements obtained from 10 Cryogenic Frost-point Hygrometer (CFH) flights and over 50 Vaisala RS92 radiosonde flights. During MOHAVE, fluorescence in all three lidar receivers was identified, causing a significant wet bias above 10-12 km in the lidar profiles as compared to the CFH. All three lidars were reconfigured after MOHAVE, and no such bias was observed during the MOHAVE-II campaign. The lidar profiles agreed very well with the CFH up to 13-17 km altitude, where the lidar measurements become noise limited. The results from MOHAVE-II have shown that the water vapor Raman lidar will be an appropriate technique for the long-term monitoring of water vapor in the UT/LS given a slight increase in its power-aperture, as well as careful calibration.

  6. Nitrate Aerosol Partitioning in the 2003 Bay Regional Atmospheric Chemistry Experiment (BRACE) : Aloft and Surface Comparisons

    NASA Astrophysics Data System (ADS)

    Arnold, J. R.; Luke, W. T.; Watson, T. B.

    2003-12-01

    The Bay Regional Atmospheric Chemistry Experiment (BRACE) field intensive in May 2003 was designed to help understand nitrogen chemistry and cycling in the airshed of Tampa, FL and included gas-phase and aerosol measurements at two downwind urban locations (Sydney and Tower Dairy) and a bay shoreline location (Gandy) as well as aboard the NOAA Twin Otter aircraft. The Twin Otter made 21 flights in the greater Tampa region over urban, suburban, and rural areas, Tampa Bay, and the Gulf of Mexico. Among these flights were several vertical profiles extending from 60 to 3000 m MSL over the Bay, the Gulf, and the ground sites. Aerosol samples on the Twin Otter were made with high flow rate filter packs followed by IC analysis; surface measurements for aerosols were made with a combination of filter packs, MOUDI samplers, annular denuders, and near-real time wet denuder collection followed by IC analysis. The degree of nitrate partitioning observed with the Twin Otter filter pack samples onto fine (2.5u and smaller) and large aerosols is examined separately for the three flow regimes that predominated during the intensive: strong synoptic, when local effects were overwhelmed; synoptic shift, with wind shifts due to changing synoptic features; and sea/bay breeze, when local effects of the sea and bay breeze forced wind shifts. Analysis of these aloft results are then compared with nitrate aerosol values on the ground.

  7. Experiences of sexual relationships of young black women in an atmosphere of coercion

    PubMed Central

    Clüver, Frances; Elkonin, Diane; Young, Charles

    2013-01-01

    Negotiations surrounding sexual activity are characterised by multiple power disparities that include race, social status and age, with gender being the most dominant differential in heterosexual interactions. Research has shown that women are physiologically more at risk of contracting HIV than men, as indicated by the higher infection rates of the former. Many African societies operate via a hegemonic masculinity, with patriarchal governance and female subordination being the norm, placing women at even greater risk of HIV infection. In this qualitative phenomenological study, four black school-going adolescent women living in Grahamstown were interviewed using a semi-structured interview to gather data. An interpretative phenomenological analysis was conducted on the data to provide subjective insights of the experiences of the participants with regard to their interactions with men. From the findings, it became apparent that the participants felt pressured, coerced or manipulated by male counterparts. This pressure and coercion was not just felt in their interactions with older men, but also in their romantic partnerships. Three of the participants experienced pressure to engage in sexual intercourse with their boyfriends when they were unwilling or unready, and they reported being faced with additional pressure to engage in unprotected sex. Furthermore, it became apparent that each participant had an underlying fear of being raped and considered this as a genuine threat to her safety and sexual health. The atmosphere within which these participants negotiate their sexual agency is thus heavily informed by male control, coercion and the threat of violence or rape. PMID:23777540

  8. Rarefied aerodynamics and upper atmospheric flight results from the Orbiter High Resolution Accelerometer Package experiment

    NASA Technical Reports Server (NTRS)

    Blanchard, R. C.; Larman, K. T.

    1987-01-01

    Data from the High Resolution Accelerometer Package (HiRAP) experiment on the Space Shuttle Orbiter have been analyzed for 10 flights to produce lift-drag (L/D) ratios in the free molecule, transition, and continuum flow flight regimes. Freestream density is also obtained in the altitude range from 60 km to 160 km using an aerodynamic model based upon earlier flight analysis of accelerometer data. The results of the L/D analysis of the latest four flights have been compared with the aerodynamic model developed from the first six HiRAP missions. The new data agree with the established flight-derived model, thereby validating earlier analysis. However, the arithmetic mean of the 10 flight-derived L/D values in the free molecular flow regime is 0.053 (+ or - 0.1) as compared to the initial value of 0.10 (+ or - 0.3), determined from STS-6. Updates to the Orbiter aerodynamic model values and calibration factors have been incorporated into the density calculations for all 10 flights to provide realistic absolute density. The derived density altitude profiles, which have been normalized to the U.S. Standard Atmosphere 1976, are characterized by a large amplitude wave pattern relative to the standard as seen in the initial flight analysis.

  9. Iterative ensemble Kalman filter for atmospheric dispersion in nuclear accidents: An application to Kincaid tracer experiment.

    PubMed

    Zhang, X L; Su, G F; Chen, J G; Raskob, W; Yuan, H Y; Huang, Q Y

    2015-10-30

    Information about atmospheric dispersion of radionuclides is vitally important for planning effective countermeasures during nuclear accidents. Results of dispersion models have high spatial and temporal resolutions, but they are not accurate enough due to the uncertain source term and the errors in meteorological data. Environmental measurements are more reliable, but they are scarce and unable to give forecasts. In this study, our newly proposed iterative ensemble Kalman filter (EnKF) data assimilation scheme is used to combine model results and environmental measurements. The system is thoroughly validated against the observations in the Kincaid tracer experiment. The initial first-guess emissions are assumed to be six magnitudes underestimated. The iterative EnKF system rapidly corrects the errors in the emission rate and wind data, thereby significantly improving the model results (>80% reduction of the normalized mean square error, r=0.71). Sensitivity tests are conducted to investigate the influence of meteorological parameters. The results indicate that the system is sensitive to boundary layer height. When the heights from the numerical weather prediction model are used, only 62.5% of reconstructed emission rates are within a factor two of the actual emissions. This increases to 87.5% when the heights derived from the on-site observations are used.

  10. The effect of seed electrons on the repeatability of atmospheric pressure plasma plume propagation: I. Experiment

    NASA Astrophysics Data System (ADS)

    Nie, L.; Chang, L.; Xian, Y.; Lu, X.

    2016-09-01

    One of the significant differences between the traditional streamers and the plasma jets is the repeatability of their propagation. In this paper, the effect of the seed electron density on the repeatability of the plasma jets is investigated. The seed electron density plays an essential role in the propagation of plasma plume which is in either repeatable mode or random mode depending on the frequency of the applied voltage and the mixture percentage of the working gas. By measuring the propagation velocities and the ignition delay time, it is found that the propagation velocities of the plasma plume are independent of the seed electron density. However, the jitter of the ignition delay time strongly depends on the frequency of the applied voltage and the mixture percentage of the working gas. After detailed analyzing of the experiment results, it is concluded that the minimum seed electron density required for the plasma bullet to propagate in repeatable mode is on the order of 108 cm-3 for gas pressure of 2 × 104 Pa. The minimum required seed electron density for the gas pressure of 4 × 103 Pa is on the order of 107 cm-3. Further analysis shows that, at one atmospheric pressure, the required minimum seed electron density for repeatable mode is on the order of 109 cm-3.

  11. Measurements of Humidity in the Atmosphere and Validation Experiments (Mohave, Mohave II): Results Overview

    NASA Technical Reports Server (NTRS)

    Leblanc, Thierry; McDermid, Iain S.; McGee, Thomas G.; Twigg, Laurence W.; Sumnicht, Grant K.; Whiteman, David N.; Rush, Kurt D.; Cadirola, Martin P.; Venable, Demetrius D.; Connell, R.; hide

    2008-01-01

    The Measurements of Humidity in the Atmosphere and Validation Experiments (MOHAVE, MOHAVE-II) inter-comparison campaigns took place at the Jet Propulsion Laboratory (JPL) Table Mountain Facility (TMF, 34.5(sup o)N) in October 2006 and 2007 respectively. Both campaigns aimed at evaluating the capability of three Raman lidars for the measurement of water vapor in the upper troposphere and lower stratosphere (UT/LS). During each campaign, more than 200 hours of lidar measurements were compared to balloon borne measurements obtained from 10 Cryogenic Frost-point Hygrometer (CFH) flights and over 50 Vaisala RS92 radiosonde flights. During MOHAVE, fluorescence in all three lidar receivers was identified, causing a significant wet bias above 10-12 km in the lidar profiles as compared to the CFH. All three lidars were reconfigured after MOHAVE, and no such bias was observed during the MOHAVE-II campaign. The lidar profiles agreed very well with the CFH up to 13-17 km altitude, where the lidar measurements become noise limited. The results from MOHAVE-II have shown that the water vapor Raman lidar will be an appropriate technique for the long-term monitoring of water vapor in the UT/LS given a slight increase in its power-aperture, as well as careful calibration.

  12. Studies of Tampa Bay Region Power Plant Plumes during the Bay Region Atmospheric Chemistry Experiment (BRACE)

    NASA Astrophysics Data System (ADS)

    Watson, T. B.; Luke, W. T.; Arnold, J. R.; Gunter, L. R.

    2003-12-01

    The NOAA Air Resources Laboratory made aircraft measurements of chemical and meteorological parameters during 21 flights of the NOAA Twin Otter as part of the Bay Region Atmospheric Chemistry Experiment (BRACE). BRACE was conducted in May 2002. The aircraft flew horizontal transects upwind and downwind of the urban area on 13 of these flights to characterize the urban and power plant plumes. Vertical profiles from 60 to 3000 m MSL were made on most flights. Profiles were made over the Gulf of Mexico, Tampa Bay, and various land sites. On many flights, transects were located immediately downwind of the urban region and power plants and at successive distances farther downwind to characterize the horizontal distribution and chemical processing of the plumes as they aged. At each distance, data was collected during multiple passes at different altitudes to characterize the vertical structure. Many of the downwind passes were flown over the Gulf where sources are limited and the plumes can be observed in relative isolation. The contribution of the power plant plumes are analyzed to determine changes in the vertical and horizontal distribution of the plumes; horizontal fluxes of NOx, NOy, and ozone; production of ozone; deposition rates; and changes on successive days of regional background and concentration maxima caused by the power plant emissions.

  13. Experiences of sexual relationships of young black women in an atmosphere of coercion.

    PubMed

    Clüver, Frances; Elkonin, Diane; Young, Charles

    2013-03-01

    Negotiations surrounding sexual activity are characterised by multiple power disparities that include race, social status and age, with gender being the most dominant differential in heterosexual interactions. Research has shown that women are physiologically more at risk of contracting HIV than men, as indicated by the higher infection rates of the former. Many African societies operate via a hegemonic masculinity, with patriarchal governance and female subordination being the norm, placing women at even greater risk of HIV infection. In this qualitative phenomenological study, four black school-going adolescent women living in Grahamstown were interviewed using a semi-structured interview to gather data. An interpretative phenomenological analysis was conducted on the data to provide subjective insights of the experiences of the participants with regard to their interactions with men. From the findings, it became apparent that the participants felt pressured, coerced or manipulated by male counterparts. This pressure and coercion was not just felt in their interactions with older men, but also in their romantic partnerships. Three of the participants experienced pressure to engage in sexual intercourse with their boyfriends when they were unwilling or unready, and they reported being faced with additional pressure to engage in unprotected sex. Furthermore, it became apparent that each participant had an underlying fear of being raped and considered this as a genuine threat to her safety and sexual health. The atmosphere within which these participants negotiate their sexual agency is thus heavily informed by male control, coercion and the threat of violence or rape.

  14. Analysis of a laboratory experiment on neutron generation by discharges in the open atmosphere

    NASA Astrophysics Data System (ADS)

    Babich, L. P.

    2015-10-01

    A recently reported laboratory experiment with a high-voltage long discharge in the open atmosphere producing neutrons "…up to energies above 10 MeV…" [Agafonov et al., Phys. Rev. Lett. 111, 115003 (2013), 10.1103/PhysRevLett.111.115003] is critically analyzed. Known elementary processes, namely, nuclear synthesis 2H(2H,n )3He and 2H(14N,n )15O , photonuclear, electrodisintegration Anm(e-,n )mprescripts>m n -1 and opposite to the β-decay e-(p+,n ) νe reactions, as well as unconventional mechanisms and the hypothetical increase in the nuclear synthesis cross sections are not capable of accounting for the neutron generation under conditions of the experiment analyzed. In particular, total energy yields of reactions 2H(2H,n )3He and 2H(14N,n )15O are less than the claimed neutron energy above 10 MeV. Trustworthiness of the neutron measurements on the basis of the available study of the C-39 track detectors behavior carried out by Faccini et al. [Eur. Phys. J. C 74, 2894 (2014), 10.1140/epjc/s10052-014-2894-3] in connection with claimed observations of neutron emission in electrolytic cells is discussed. Real-time measurements of x-ray and neutron pulses by Agafonov et al. are commented on using the thorough study of the x-ray emissions by discharges under similar conditions [Kochkin et al., J. Phys. D: Appl. Phys. 45, 425202 (2012), 10.1088/0022-3727/45/42/425202].

  15. Application of the Satellite Triaxial Accelerometer Experiment to Atmospheric Density and Wind Studies.

    DTIC Science & Technology

    1982-03-04

    EVERETT R. SWIFT U DTIC " 4 MARCH 1982 -J_ OCT 2 9 1 3 Approed for publis rebo.; dlributon unlimited. AERONOMY DIVISION PROJECT 6690 , AIR FORCE...Accelerometers Thermospheric density; . * Aerodynic drag Atmospheric density -- A new satellite triaxial accelerometer system has been developed. This...understanding of dynamic processes in the atmosphere and for the improvement of atmospheric models. i’ :. 4 Unclassified SECURITY CLASSIFICATION OF THIS

  16. Occultation Experiment: Results of the First Direct Measurement of Mars's Atmosphere and Ionosphere.

    PubMed

    Kliore, A; Cain, D L; Levy, G S; Eshleman, V R; Fjeldbo, G; Drake, F D

    1965-09-10

    Changes in the frequency, phase, and amplitude of the Mariner IV radio signal, caused by passage through the atmosphere and ionosphere of Mars, were observed immediately before and after occultation by the planet. Preliminary analysis of these effects has yielded estimates of the refractivity and density of the atmosphere near the surface, the scale height in the atmosphere, and the electron density profile of the Martian ionosphere. The atmospheric density, temperature, and scale height are lower than previously predicted, as are the maximum density, temperature, scale height, and altitude of the ionosphere.

  17. CalWater 2 - Precipitation, Aerosols, and Pacific Atmospheric Rivers Experiment

    NASA Astrophysics Data System (ADS)

    Spackman, Ryan; Ralph, Marty; Prather, Kim; Cayan, Dan; DeMott, Paul; Dettinger, Mike; Fairall, Chris; Leung, Ruby; Rosenfeld, Daniel; Rutledge, Steven; Waliser, Duane; White, Allen

    2014-05-01

    Emerging research has identified two phenomena that play key roles in the variability of the water supply and the incidence of extreme precipitation events along the West Coast of the United States. These phenomena include the role of (1) atmospheric rivers (ARs) in delivering much of the precipitation associated with major storms along the U.S. West Coast, and (2) aerosols—from local sources as well as those transported from remote continents—and their modulating effects on western U.S. precipitation. A better understanding of these processes is needed to reduce uncertainties in weather predictions and climate projections of extreme precipitation and its effects, including the provision of beneficial water supply. This presentation summarizes science gaps associated with (1) the evolution and structure of ARs including cloud and precipitation processes and air-sea interaction, and (2) aerosol interaction with ARs and the impact on precipitation, including locally-generated aerosol effects on orographic precipitation along the U.S. West Coast. Observations are proposed for multiple winter seasons as part of a 5-year broad interagency vision referred to as CalWater 2 to address these science gaps (http://esrl.noaa.gov/psd/calwater). In the near term, a science investigation is being planned including a targeted set of aircraft and ship-based measurements and associated evaluation of data in near-shore regions of California and in the eastern Pacific for an intensive observing period between January 2015 and March 2015. DOE's Atmospheric Radiation Measurement (ARM) program and NOAA are coordinating on deployment of airborne and ship-borne facilities for this period in a DOE-sponsored study called ACAPEX (ARM Cloud Aerosol and Precipitation Experiment) to complement CalWater 2. The motivation for this major study is based on findings that have emerged in the last few years from airborne and ground-based studies including CalWater and NOAA's HydroMeterology Testbed

  18. Laboratory Experiments and Instrument Development for the Study of Atmospheric Aerosols

    SciTech Connect

    Davidovits, Paul

    2011-12-10

    Soot particles are generated by incomplete combustion of fossil and biomass fuels. Through direct effects clear air aerosols containing black carbon (BC) such as soot aerosols, absorb incoming light heating the atmosphere, while most other aerosols scatter light and produce cooling. Even though BC represents only 1-2% of the total annual emissions of particulate mass to the atmosphere, it has been estimated that the direct radiative effect of BC is the second-most important contributor to global warming after absorption by CO2. Ongoing studies continue to underscore the climate forcing importance of black carbon. However, estimates of the radiative effects of black carbon on climate remain highly uncertain due to the complexity of particles containing black carbon. Quantitative measurement of BC is challenging because BC often occurs in highly non-spherical soot particles of complex morphology. Freshly emitted soot particles are typically fractal hydrophobic aggregates. The aggregates consist of black carbon spherules with diameters typically in the range of about 15-40 nm, and they are usually coated by adsorbed polyaromatic hydrocarbons (PAHs) produced during combustion. Diesel-generated soot particles are often emitted with an organic coating composed primarily of lubricating oil and unburned fuel, as well as well as PAH compounds. Sulfuric acid has also been detected in diesel and aircraft-emitted soot particles. In the course of aging, these particle coatings may be substantially altered by chemical reactions and/or the deposition of other materials. Such processes transform the optical and CCN properties of the soot aerosols in ways that are not yet well understood. Our work over the past seven years consisted of laboratory research, instrument development and characterization, and field studies with the central focus of improving our understanding of the black carbon aerosol climate impacts. During the sixth year as well as during this seventh year (no

  19. The Passy-2015 field experiment: wintertime atmospheric dynamics and air quality in a narrow alpine valley

    NASA Astrophysics Data System (ADS)

    Paci, Alexandre; Staquet, Chantal

    2016-04-01

    Wintertime anticyclonic conditions lead to the formation of persistent stable boundary layers which may induce severe air pollution episodes in urban or industrialized area, particularly in mountain regions. The Arve river valley in the Northern Alps is very sensitive to this phenomenon, in particular close to the city of Passy (Haute-Savoie), 20 km down valley past Chamonix. This place is indeed one of the worst place in France regarding air quality, the concentration of fine particles and Benzo(a)pyrene (a carcinogenic organic compound) regularly exceeding the EU legal admissible level during winter. Besides air quality measurements, such as the ones presently carried in the area by the local air quality agency Air Rhône-Alpes or in the DECOMBIO project led by LGGE, it is crucial to improve our knowledge of the atmospheric boundary layer dynamics and processes at the valley scale under these persistent stable conditions in order to improve our understanding on how it drives pollutant dispersion. These issues motivated the Passy-2015 field experiment which took place during the winter 2014-2015. A relatively large set-up of instruments was deployed on a main measurement site in the valley center and on four other satellite sites. It includes several remote sensing instruments, a surface flux station, a 10 m instrumented tower, a large aperture scintillometer, a fog monitoring station among others. Most of the instruments were present from early January to the end of February. During two intensive observation periods, 6-14 February and 17-20 February, the instrumental set-up was completed on the main site with high frequency radio-soundings (up to one per 1h30), a tethered balloon, a remote controlled drone quadcopter and a sodar. The field campaign, the instruments, the meteorological situations observed and preliminary results will be presented. This field experiment is part of the Passy project funded by ADEME through the French national programme LEFE/INSU and

  20. A model for eastward and westward jets in laboratory experiments and planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Marcus, P. S.; Lee, C.

    1998-06-01

    Flows in a rotating annular tank [J. Sommeria, S. D. Meyers, and H. L. Swinney, Nonlinear Topics in Ocean Physics, edited by A. Osborne (North Holland, Amsterdam, 1991); Nature (London) 337, 58 (1989); T. H. Solomon, W. J. Holloway, and H. L. Swinney, Phys. Fluids A 5, 1971 (1993); J. Sommeria, S. D. Meyers, and H. L. Swinney, Nature (London) 331, 689 (1989)] with a sloping bottom (that simulates a barotropic atmosphere's Coriolis force with a topographic β-effect [J. Pedlosky, Geophysical Fluid Dynamics, 2nd ed. (Springer, Berlin, 1986)]) produce eastward and westward jets, i.e., azimuthal flows moving in the same or opposite direction as the annulus' rotation. Flows are forced by pumping fluid in and out of two concentric slits in the bottom boundary, and the direction of the jets depends on the direction of the pumping. The eastward and westward jets differ, with the former narrow, strong, and wavy. The jets of Jupiter and Saturn have the same east-west asymmetry [P. S. Marcus, Ann. Rev. Astron. Astro. 431, 523 (1993)]. Numerical simulations show that the azimuthally-averaged flow differs substantially from the non-averaged flow which has sharp gradients in the potential vorticity q. They also show that the maxima of the eastward jets and Rossby waves are located where the gradients of q are large, and the maxima of the westward jets and vortex chains are located where they are weak. As the forcing is increased the drift velocities of the two chains of vortices of the eastward jet lock together; whereas the two chains of the westward jet do not. Inspired by a previously published, [P. S. Marcus, Ann. Rev. Astron. Astro. 431, 523 (1993)] piece-wise constant-q model of the Jovian jets and based on numerical simulations, a new model of the experimental flow that is characterized by regions of undisturbed flow and bands of nearly uniform q separated by sharp gradients is presented. It explains the asymmetry of the laboratory jets and quantitatively describes all of

  1. Effects of Explicit Convection on Land-Atmosphere Coupling in GLACE-Type Experiments Using the SuperParameterized CAM

    NASA Astrophysics Data System (ADS)

    Qin, H.; Pritchard, M. S.; Parishani, H.

    2016-12-01

    Understanding and realistically simulating the coupling between land and atmosphere in global climate models (GCMs) is an ongoing research frontier. We explore the hypothesis that past attempts to investigate these physics using GCM mechanism denial experiments may have suffered systematic limitations stemming from an overly strong sensitivity of deep convection parameterizations to surface conditions. Taking the philosophy of the Global Land-Atmosphere Coupling Experiment (GLACE), we therefore compare the effects of breaking the soil-atmosphere feedback mechanism in the Super-Parameterized Community Atmosphere Model version 3.5 (SPCAM3.5) - which uses O(10k) embedded cloud resolving models to explicitly resolve moist convection - against the conventionally parameterized CAM3.5. This helps isolate the influence of explicit convection on land-atmosphere coupling. We find that soil moisture - precipitation coupling strength is reduced over northern Africa, northern South America and Arabian Peninsula due to superparameterization. Several geographically distinct coupling "hotspots" emerge in SPCAM3.5 located upstream of major topographic features in the Northern Hemisphere mid-latitudes.

  2. Data processing technique for multiangle lidar sounding of poorly stratified polluted atmospheres: Theory and experiment

    Treesearch

    Cyle E. Wold; Vladimir A. Kovalev; Alexander P. Petkov; Wei Min Hao

    2012-01-01

    Scanning elastic lidar, which can operate in different slant directions, is the most appropriate remote sensing tool for investigating the optical properties of smoke-polluted atmospheres. However, the commonly used methodologies of multiangle measurements are based on the assumption of horizontal stratification of the searched atmosphere1,2. When working in real...

  3. Response of Atmospheric-Methane Oxidation to Methane-Flux Manipulation in a Laboratory Soil-Column Experiment

    NASA Astrophysics Data System (ADS)

    Schroth, M. H.; Mignola, I.; Henneberger, R.

    2015-12-01

    Upland soils are an important sink for atmospheric methane (CH4). Uptake of atmospheric CH4 in soils is generally diffusion limited, and is mediated by aerobic CH4 oxidizing bacteria (MOB) that possess a high-affinity form of a key enzyme, allowing CH4 consumption at near-atmospheric concentrations (≤ 1.9 µL/L). As cultivation attempts for these high-affinity MOB have shown little success, there remains much speculation regarding their functioning in different environments. For example, it is frequently assumed that they are highly sensitive to physical disturbance, but their response in activity and abundance to changes in substrate availability remains largely unknown. We present results of a laboratory column experiment conducted to investigate the response in activity and abundance of high-affinity MOB to an increase in CH4 flux. Intact soil cores, collected at a field site where atmospheric CH4 oxidation activity is frequently quantified, were transferred into two 1-m-long, 12-cm-dia. columns. The columns were operated at constant temperature in the dark, their headspace being continuously flushed with air. Diffusive gas-transport conditions were maintained in the reference column, whereas CH4 flux was increased in several steps in the treatment column by inducing advective gas flow using a diaphragm pump. Soil-gas samples periodically collected from ports installed along the length of the columns were analyzed for CH4 content. Together with measurements of soil-water content, atmospheric CH4 oxidation was quantified using the soil-profile method. First results indicate that atmospheric CH4 oxidation activity comparable with the field was maintained in the reference column throughout the experiment. Moreover, high-affinity MOB quickly adjusted to an increase in CH4 flux in the treatment column, efficiently consuming CH4. Quantification of MOB abundance is currently ongoing. Our data provide new insights into controls on atmospheric CH4 oxidation in soils.

  4. Photochemistry of iron(III)-carboxylato complexes in aqueous atmospheric particles - Laboratory experiments and modeling studies

    NASA Astrophysics Data System (ADS)

    Weller, C.; Tilgner, A.; Herrmann, H.

    2010-12-01

    Iron is always present in the atmosphere in concentrations from ~10-9 M (clouds, rain) up to ~10-3 M (fog, particles). Sources are mainly mineral dust emissions. Iron complexes are very good absorbers in the UV-VIS actinic region and therefore photo-chemically reactive. Iron complex photolysis leads to radical production and can initiate radical chain reactions, which is related to the oxidizing capacity of the atmosphere. These radical chain reactions are involved in the decomposition and transformation of a variety of chemical compounds in cloud droplets and deliquescent particles. Additionally, the photochemical reaction itself can be a degradation pathway for organic compounds with the ability to bind iron. Iron-complexes of atmospherically relevant coordination compounds like oxalate, malonate, succinate, glutarate, tartronate, gluconate, pyruvate and glyoxalate have been investigated in laboratory experiments. Iron speciation depends on the iron-ligand ratio and the pH. The most suitable experimental conditions were calculated with a speciation program (Visual Minteq). The solutions were prepared accordingly and transferred to a 1 cm quartz cuvette and flash-photolyzed with an excimer laser at wavelengths 308 or 351 nm. Photochemically produced Fe2+ has been measured by spectrometry at 510 nm as Fe(phenantroline)32+. Fe2+ overall effective quantum yields have been calculated with the concentration of photochemically produced Fe2+ and the measured energy of the excimer laser pulse. The laser pulse energy was measured with a pyroelectric sensor. For some iron-carboxylate systems the experimental parameters like the oxygen content of the solution, the initial Iron concentration and the incident laser energy were systematically altered to observe an effect on the overall quantum yield. The dependence of some quantum yields on these parameters allows in some cases an interpretation of the underlying photochemical reaction mechanism. Quantum yields of malonate

  5. A Markov Chain Monte Carlo Algorithm for Infrasound Atmospheric Sounding: Application to the Humming Roadrunner experiment in New Mexico

    NASA Astrophysics Data System (ADS)

    Lalande, Jean-Marie; Waxler, Roger; Velea, Doru

    2016-04-01

    As infrasonic waves propagate at long ranges through atmospheric ducts it has been suggested that observations of such waves can be used as a remote sensing techniques in order to update properties such as temperature and wind speed. In this study we investigate a new inverse approach based on Markov Chain Monte Carlo methods. This approach as the advantage of searching for the full Probability Density Function in the parameter space at a lower computational cost than extensive parameters search performed by the standard Monte Carlo approach. We apply this inverse methods to observations from the Humming Roadrunner experiment (New Mexico) and discuss implications for atmospheric updates, explosion characterization, localization and yield estimation.

  6. Development of a differential pumping system for soft X-ray beamlines for windowless experiments under normal atmospheric conditions.

    PubMed

    Tamenori, Y

    2010-03-01

    A novel design for a differential pumping system has been investigated. This system allows windowless experiments in a soft X-ray beamline under normal atmospheric conditions. The new design consists of an aperture-based four-stage differential pumping system, based on a simple model calculation. A prototype system with a total length of 600 mm was constructed to confirm the validity of the design concept. Relatively short conductance-limiting components allow easy installation and alignment of the system on a synchrotron beamline. The fabricated system was installed on a beamline to test the transmission of soft X-rays through atmospheric helium.

  7. Carbon Dioxide (CO2) Retrievals from Atmospheric Chemistry Experiment (ACE) Solar Occultation Measurements

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Chiou, Linda; Boone, Chris; Bernath, Peter

    2010-01-01

    The Atmospheric Chemistry Experiment ACE satellite (SCISAT-1) was launched into an inclined orbit on 12 August 2003 and is now recording high signal-to-noise 0.02 per centimeter resolution solar absorption spectra covering 750-4400 per centimeter (2.3-13 micrometers). A procedure has been developed for retrieving average dry air CO2 mole fractions (X(sub CO2)) in the altitude range 7-10 kilometers from the SCISAT-1 spectra. Using the N2 continuum absorption in a window region near 2500 per centimeter, altitude shifts are applied to the tangent heights retrieved in version 2.2 SCISAT-1 processing, while cloudy or aerosol-impacted measurements are eliminated. Monthly-mean XCO2 covering 60 S to 60 N latitude for February 2004 to March 2008 has been analyzed with consistent trends inferred in both hemispheres. The ACE XCO2 time series have been compared with previously-reported surface network measurements, predictions based on upper tropospheric aircraft measurements, and space-based measurements. The retrieved X(sub CO2) from the ACE-FTS spectra are higher on average by a factor of 1.07 plus or minus 0.025 in the northern hemisphere and by a factor of 1.09 plus or minus 0.019 on average in the southern hemisphere compared to surface station measurements covering the same time span. The ACE derived trend is approximately 0.2% per year higher than measured at surface stations during the same observation period.

  8. Atmospheric Transport During the Transport and Chemical Evolution over the Pacific TRACE-P Experiment

    NASA Technical Reports Server (NTRS)

    Fuelberg, Henry E.; Kiley, C. M.; Hannan, J. R.; Westberg, D. J.; Avery, M. A.; Newell, R. E.

    2003-01-01

    Atmospheric transport over the Pacific Basin is described during NASA's Transport and Chemical Evolution Over the Pacific Experiment (TRACE-P) that was conducted between February - April 2001. The mission included extensive chemical sampling from two aircraft based primarily in Hong Kong and Yokota Air Base, Japan. Meteorological conditions during TRACE-P changed rapidly due to the seasonal winter/spring transition and the decay of prolonged ENSO cold phase (La Nina) conditions. To document these changes, TRACE-P was divided into two halves, and mean flow patterns during each half are presented and discussed. Important circulation features are the semi-permanent Siberian anticyclone and transient middle latitude cyclones that form near eastern Asia and then move eastward over the northern Pacific. Five-day backward trajectories from the various flight tracks show that air sampled by the aircraft had been transported from a variety of locations. Some parcels remained over the tropical western North Pacific during the entire period, while other important origins were Southeast Asia, Africa, and central Asia. Patterns of satellite-derived precipitation and lightning are described. TRACE-P occurs during a neutral to weak La Nina period of relatively cold sea surface temperatures in the tropical Pacific. Compared to climatology, the TRACE-P period exhibits deep convection located west of its typical position; however, tropospheric flow patterns do not exhibit a strong La Nina signal. Circulation patterns during TRACE-P are found to be generally similar to those during NASA's PEM WEST-B mission that occurred in the same region during February - March 1994.

  9. Atmospheric Transport During the Transport and Chemical Evolution over the Pacific TRACE-P Experiment

    NASA Technical Reports Server (NTRS)

    Fuelberg, Henry E.; Kiley, C. M.; Hannan, J. R.; Westberg, D. J.; Avery, M. A.; Newell, R. E.

    2003-01-01

    Atmospheric transport over the Pacific Basin is described during NASA's Transport and Chemical Evolution Over the Pacific Experiment (TRACE-P) that was conducted between February - April 2001. The mission included extensive chemical sampling from two aircraft based primarily in Hong Kong and Yokota Air Base, Japan. Meteorological conditions during TRACE-P changed rapidly due to the seasonal winter/spring transition and the decay of prolonged ENSO cold phase (La Nina) conditions. To document these changes, TRACE-P was divided into two halves, and mean flow patterns during each half are presented and discussed. Important circulation features are the semi-permanent Siberian anticyclone and transient middle latitude cyclones that form near eastern Asia and then move eastward over the northern Pacific. Five-day backward trajectories from the various flight tracks show that air sampled by the aircraft had been transported from a variety of locations. Some parcels remained over the tropical western North Pacific during the entire period, while other important origins were Southeast Asia, Africa, and central Asia. Patterns of satellite-derived precipitation and lightning are described. TRACE-P occurs during a neutral to weak La Nina period of relatively cold sea surface temperatures in the tropical Pacific. Compared to climatology, the TRACE-P period exhibits deep convection located west of its typical position; however, tropospheric flow patterns do not exhibit a strong La Nina signal. Circulation patterns during TRACE-P are found to be generally similar to those during NASA's PEM WEST-B mission that occurred in the same region during February - March 1994.

  10. Intercomparison of stratospheric water vapor observed by satellite experiments - Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy

    NASA Technical Reports Server (NTRS)

    Chiou, E. W.; Mccormick, M. P.; Mcmaster, L. R.; Chu, W. P.; Larsen, J. C.; Rind, D.; Oltmans, S.

    1993-01-01

    A comparison is made of the stratospheric water vapor measurements made by the satellite sensors of the Stratospheric Aerosol and Gas Experiment II (SAGE II), the Nimbus-7 LIMS, and the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. It was found that, despite differences in the measurement techniques, sampling bias, and observational periods, the three experiments have disclosed a generally consistent pattern of stratospheric water vapor distribution. The only significant difference occurs at high southern altitudes in May below 18 km, where LIMS measurements were 2-3 ppmv greater than those of SAGE II and ATMOS.

  11. Instrumentation on the Remote Atmospheric and Ionospheric Detection System Experiment: Extreme-ultraviolet spectrometer, photometer, and near infrared spectrometer

    SciTech Connect

    Christensen, A.B.; Kayser, D.C.; Pranke, J.B.; Straus, P.R.; Gutierrez, D.G. . Space and Environment Technology Center); Chakrabarti, S. . Center for Space Physics); McCoy, R.P.; Meier, R.R.; Wolfram, K.D.; Picone, J.M. . E.O. Hulbert Center for Space Research)

    1993-12-01

    The Remote Atmospheric and Ionospheric Detection System experiment consists of eight instruments spanning the wavelength range from the extreme ultraviolet (55 nm) to the near infrared (800 nm) oriented to view the Earth's limb from the National Oceanic and Atmospheric Administration TIROS-J spacecraft to be launched into a circular orbit in 1993. Through measurements of the natural optical emissions and scattered sunlight originating in the upper atmosphere including the mesosphere and thermosphere, state variables such as temperature, composition, density, and ion concentration of this region will be inferred. The subset of instruments fabricated or otherwise provided by the Space and Environment Technology Center (formerly Space Sciences Laboratory) at The Aerospace Corporation are described.

  12. Retrieval and molecule sensitivity studies for the global ozone monitoring experiment and the scanning imaging absorption spectrometer for atmospheric chartography

    NASA Technical Reports Server (NTRS)

    Chance, Kelly V.; Burrows, John P.; Schneider, Wolfgang

    1991-01-01

    The Global Ozone Monitoring Experiment (GOME) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) are diode based spectrometers that will make atmospheric constituent and aerosol measurements from European satellite platforms beginning in the mid 1990's. GOME measures the atmosphere in the UV and visible in nadir scanning, while SCIAMACHY performs a combination of nadir, limb, and occultation measurements in the UV, visible, and infrared. A summary is presented of the sensitivity studies that were performed for SCIAMACHY measurements. As the GOME measurement capability is a subset of the SCIAMACHY measurement capability, the nadir, UV, and visible portion of the studies is shown to apply to GOME as well.

  13. An investigation of the effects of mass loss, shape change and real gas aerodynamics on a Jovian atmospheric reconstruction experiment

    NASA Technical Reports Server (NTRS)

    Walberg, G. D.; Jones, J. J.; Olstad, W. B.; Sutton, K.; Moss, J. N.; Powell, R. W.

    1976-01-01

    A survey of the effects of mass loss, shape change and real-gas aerodynamics on a Jovian atmospheric reconstruction experiment is carried out. Techniques used to reconstruct atmospheric profiles from entry probe measurements are discussed and some of the parameters which affect their accuracy are identified. Trajectory analyses and real-gas, radiatively-coupled flow field analyses (which include the effects of mass loss and shape change) are carried out for several candidate probe configurations. From these analyses, uncertainties in the atmospheric reconstruction procedure are estimated. Finally, the prospects for reducing these uncertainties by optimizing probe configuration and by instrumentation of the probe heat shield to measure actual shape change are considered.

  14. Preliminary results on the atmospheres of Io and Jupiter from the Pioneer 10 S-band occultation experiment

    NASA Technical Reports Server (NTRS)

    Kliore, A.; Cain, D. L.; Fjeldbo, G.; Seidel, B. L.; Rasool, S. I.

    1974-01-01

    The preliminary analysis of data from the Pioneer 10 S-band radio occultation experiment has revealed the presence of an ionosphere on the Jovian satellite Io having an electron density peak of about 60,000 electrons per cubic centimeter at an altitude of approximately 60 to 140 kilometers. This suggests the presence of an atmosphere having a surface number density of about 10 billion to one trillion per cubic centimeter, corresponding to an atmospheric surface pressure of between .1 and 10 nanobar, at or below the detection threshold of the Beta Scorpii stellar occultation. A measurement of the atmosphere of Jupiter was obtained down to the level of about 80 millibars, indicating a large temperature increase at about the 20 millibar level, which cannot be explained by the absorption of solar radiation by methane alone and can possibly be due to absorption by particulate matter.

  15. Results from a Set of Three-Dimensional Numerical Experiments of a Hot Jupiter Atmosphere

    NASA Technical Reports Server (NTRS)

    Mayne, Nathan J.; Debras, Flirian; Baraffe, Isabelle; Thuburn, John; Amundsen, David S.; Acreman, David M.; Smith, Chris; Browning, Matthew K.; Manners, James; Wood Nigel

    2017-01-01

    We present highlights from a large set of simulations of a hot Jupiter atmosphere, nominally based on HD 209458b, aimed at exploring both the evolution of the deep atmosphere, and the acceleration of the zonal flow or jet. We find the occurrence of a super-rotating equatorial jet is robust to changes in various parameters, and over long timescales, even in the absence of strong inner or bottom boundary drag. This jet is diminished in one simulation only, where we strongly force the deep atmosphere equator-to-pole temperature gradient over long timescales. Finally, although the eddy momentum fluxes in our atmosphere show similarities with the proposed mechanism for accelerating jets on tidally-locked planets, the picture appears more complex. We present tentative evidence for a jet driven by a combination of eddy momentum transport and mean flow.

  16. A Concept Study for the Mars Atmosphere Experiment for Ceramic Oxygen Generation (MAXCOG)

    NASA Astrophysics Data System (ADS)

    Christian, J. A.; Sabolsky, E.; Rohschneider, R.; Gerdes, K.; Mebane, D.; Zondlo, J. W.; Liu, X.; Unruh, B.; Hanel, J.; Kleinhenz, J.

    2014-07-01

    MAXCOG is an ISRU precursor concept that matures enabling technologies for future exploration missions to Mars. This concept uses a Solid-Oxide Electrolysis Cell (SOEC)-based solution to produce propellant-grade oxygen from the martian atmosphere.

  17. Results from a set of three-dimensional numerical experiments of a hot Jupiter atmosphere

    NASA Astrophysics Data System (ADS)

    Mayne, Nathan J.; Debras, Florian; Baraffe, Isabelle; Thuburn, John; Amundsen, David S.; Acreman, David M.; Smith, Chris; Browning, Matthew K.; Manners, James; Wood, Nigel

    2017-08-01

    We present highlights from a large set of simulations of a hot Jupiter atmosphere, nominally based on HD 209458b, aimed at exploring both the evolution of the deep atmosphere, and the acceleration of the zonal flow or jet. We find the occurrence of a super-rotating equatorial jet is robust to changes in various parameters, and over long timescales, even in the absence of strong inner or bottom boundary drag. This jet is diminished in one simulation only, where we strongly force the deep atmosphere equator-to-pole temperature gradient over long timescales. Finally, although the eddy momentum fluxes in our atmosphere show similarities with the proposed mechanism for accelerating jets on tidally-locked planets, the picture appears more complex. We present tentative evidence for a jet driven by a combination of eddy momentum transport and mean flow.

  18. Results of the Balloon Atmospheric Propagation Experiment flights of 1970 (BAPE 1)

    NASA Technical Reports Server (NTRS)

    Minott, P. O.; Bufton, J. L.; Fitzmaurice, M. W.

    1972-01-01

    Two laser beams, one argon (5145 A) and one CO2 (10.6 microns), were propagated over vertical path from the ground to receivers located above the atmosphere, and the scintillation of the beams was measured. Simulataneous measurement of the state of turbulence along the path permitted the comparison of scintillation statistics with theory. The effects of atmospheric turbulence over a vertical or near-vertical path are discussed.

  19. Validation and Drift Analysis for the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) Trace Gas Data Set

    NASA Astrophysics Data System (ADS)

    Walker, K. A.; Sheese, P.; Zou, J.; Boone, C. D.; Bernath, P. F.

    2016-12-01

    To progress from monitoring atmospheric composition to investigating and quantifying atmospheric changes, well-characterized measurements over many years are required. The long lifetime of the Atmospheric Chemistry Experiment (ACE) has provided more than a decade of composition measurements that contribute to our understanding of ozone recovery, climate change and pollutant emissions. The primary ACE instrument on SCISAT is a high-resolution (0.02 cm-1) Fourier Transform Spectrometer (ACE-FTS) operating between 750 and 4400 cm-1. The ACE-FTS data set provides profiles of temperature, pressure, and volume mixing ratios of more than 30 atmospheric trace gas species, as well as 20 subsidiary isotopologues of the most abundant trace atmospheric constituents. The profiles from this Canadian scientific satellite mission provide altitude-resolved data that are necessary for understanding processes that occur at specific altitudes or over limited vertical length scales. This paper will describe current validation results for the ACE-FTS version 3.5 data set and describe the drift analyses that are being undertaken to characterize these data to enable the generation of climate data records.

  20. The Atmospheric Neutral Density Experiment (ANDE) and Modulating Retroreflector in Space (MODRAS): Combined Flight Experiments for the Space Test Program

    DTIC Science & Technology

    2003-01-01

    be tracked by the SSN who will provide accurate orbital state vectors for each sphere. The SLR site can then use these state vectors to acquire the...atmospheric composition, cross- track winds and neutral temperature; a Global Positioning Sensor (GPS); and a Thermal Monitoring System (TMS) to...of the three models discussed above is plotted. Note that the three models track each other for most of the large trends although small deviations

  1. The Greatest Legacy of the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA): A Bibliometric Assessment

    NASA Astrophysics Data System (ADS)

    Keller, M. M.

    2015-12-01

    The Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA) is an international continental scale effort led by Brazil to understand how land use change and climate change affects the role of Amazonia in the Earth system. During the first decade of studies (1998-2007), LBA researchers generated new understanding of Amazonia and published over 1000 papers. However, most LBA participants agree that training and education of a large cohort of scientists, especially students from Brazil, was the greatest contribution of LBA. I analyzed bibliographic data from the NASA supported component project known as LBA-ECO. This component covered a large cross-section of the LBA subject areas highlighting land use and land cover change, carbon cycling, nutrient cycling and other aspects of terrestrial and aquatic ecology. I reviewed the complete bibliography of peer-reviewed papers reported by LBA-ECO researchers (http://www.lbaeco.org/cgi-bin/web/investigations/lbaeco_refs.pl). The researchers reported 691 contributions from 1996 through 2013 of which 24 were theses that were removed them from further analysis. Of 667 papers and book chapters, I tallied the first authors separating categories for Brazilians, all students, and Brazilian students. Numerically, LBA-ECO production of papers peaked in 2004. Publication by Brazilians, students, and Brazilian students generally followed the same pattern as publication in general. However, student and Brazilian student contributions as first authors showed clearly increasing proportions of the papers from project initiation through peak publication. Brazilian student participation as first authors averaged more than 20% of all publications from 2003 to 2010 and more than half of all student publications had Brazilians as first authors. Foreign researchers, some initially reluctant to invest in Brazilian students, almost universally adapted the belief that the greatest legacy of LBA would be the contribution to building a cadre of

  2. Wind tunnel experiments: cold-air pooling and atmospheric decoupling above a melting snow patch

    NASA Astrophysics Data System (ADS)

    Mott, Rebecca; Paterna, Enrico; Horender, Stefan; Crivelli, Philip; Lehning, Michael

    2016-02-01

    The longevity of perennial snowfields is not fully understood, but it is known that strong atmospheric stability and thus boundary-layer decoupling limit the amount of (sensible and latent) heat that can be transmitted from the atmosphere to the snow surface. The strong stability is typically caused by two factors, (i) the temperature difference between the (melting) snow surface and the near-surface atmosphere and (ii) cold-air pooling in topographic depressions. These factors are almost always a prerequisite for perennial snowfields to exist. For the first time, this contribution investigates the relative importance of the two factors in a controlled wind tunnel environment. Vertical profiles of sensible heat and momentum fluxes are measured using two-component hot-wire and one-component cold-wire anemometry directly over the melting snow patch. The comparison between a flat snow surface and one that has a depression shows that atmospheric decoupling is strongly increased in the case of topographic sheltering but only for low to moderate wind speeds. For those conditions, the near-surface suppression of turbulent mixing was observed to be strongest, and the ambient flow was decoupled from the surface, enhancing near-surface atmospheric stability over the single snow patch.

  3. Shuttle high resolution accelerometer package experiment results - Atmospheric density measurements between 60-160 km

    NASA Technical Reports Server (NTRS)

    Blanchard, R. C.; Hinson, E. W.; Nicholson, J. Y.

    1988-01-01

    Indirect or inferred values of atmospheric density encountered by the Shuttle Orbiter during reentry have been calculated from acceleration measurements made by the High Resolution Accelerometer Package (HiRAP) and the Orbiter Inertial Measurement Unit (IMU) liner accelerometers. The atmospheric density data developed from this study represent a significant gain with respect to the body of data collected to date by various techniques in the altitude range of 60 to 160 km. The data are unique in that they cover a very wide horizontal range during each flight and provide insight into the actual density variations encountered along the reentry flight path. The data, which were collected over about 3 years, are also characterized by variations in solar activity, geomagnetic index, and local solar time. Comparison of the flight-derived densities with various atmospheric models have been made, and analyses have attempted to characterize the data and to show correlation with selected physical variables.

  4. Spacelab 2 Upper Atmospheric Modification experiment over Arecibo. I - Neutral gas dynamics

    NASA Technical Reports Server (NTRS)

    Bernhardt, P. A.; Kashiwa, B. A.; Tepley, C. A.; Noble, S. T.

    1988-01-01

    The Orbital Maneuvering Subsystem engines of the Space Shuttle were used to inject H2, CO2, H2O and other combustion products into the upper atmosphere over the Arecibo Observatory. Images of the airglow enhancements that resulted from chemical reactions between the exhaust gases and the F-layer plasma showed that the exhaust vapor trail came to rest 80 km downstream from the center of the burn. A computer simulation of the gas dynamics shows that the region of the burn was dominated by a 'snow plow' effect sweeping out a corridor in the atmosphere and collisionally heating the injected vapors.

  5. Sensitivity of the thermohaline circulation in coupled oceanic GCM — atmospheric EBM experiments

    NASA Astrophysics Data System (ADS)

    Lohmann, Gerrit; Gerdes, Rüdiger; Chen, Deliang

    1996-05-01

    We analyze the sensitivity of the oceanic thermohaline circulation (THC) regarding perturbations in fresh water flux for a range of coupled oceanic general circulation — atmospheric energy balance models. The energy balance model (EBM) predicts surface air temperature and fresh water flux and contains the feedbacks due to meridional transports of sensible and latent heat. In the coupled system we examine a negative perturbation in run-off into the southern ocean and analyze the role of changed atmospheric heat transports and fresh water flux. With mixed boundary conditions (fixed air temperature and fixed surface fresh water fluxes) the response is characterized by a completely different oceanic heat transport than in the reference case. On the other hand, the surface heat flux remains roughly constant when the air temperature can adjust in a model where no anomalous atmospheric transports are allowed. This gives an artificially stable system with nearly unchanged oceanic heat transport. However, if meridional heat transports in the atmosphere are included, the sensitivity of the system lies between the two extreme cases. We find that changes in fresh water flux are unimportant for the THC in the coupled system.

  6. The Atmospheric Lifetime Experiment. VI - Results for carbon tetrachloride based on 3 years data

    NASA Astrophysics Data System (ADS)

    Simmonds, P. G.; Alyea, F. N.; Cardelino, C. A.; Cunnold, D. M.; Crawford, A. J.; Rasmussen, R. A.; Lane, B. C.; Lovelock, J. E.; Prinn, R. G.

    1983-10-01

    The automated electron capture gas chromatographic determination of the atmospheric concentrations of CCl4 are reported for the period July 1978 to June 1981 at five coastal monitoring stations, Adrigole (Ireland), Cape Meares (Oregon), Ragged Point (Barbados, West Indies), Point Matatula (American Samoa), and Cape Grim (Tasmania). Daily measurements at approximately 6-hourly intervals are always complemented by an equivalent number of on-site calibration measurements. Estimates of CCl4 emissions to the atmosphere from known industrial sources are compared with the measured trends and the absolute values of the observed concentrations. A globally averaged atmospheric lifetime for CCl4 is calculated by using an optimal estimation technique incorporating a nine-box model of the atmosphere. The average global concentration of CCl4 from July 1978 to June 1981 in the lower troposphere was 118 pptv, and it was increasing 2.1 pptv/year over this period. Both the absolute concentration observed and its trend are consistent with the calculated releases of CCl4 and its expected destruction by stratospheric photolysis.

  7. Thermal emission spectra of the Earth and atmosphere from the Nimbus 4 Michelson interferometer experiment.

    PubMed

    Hanel, R A; Conrath, B J

    1970-10-10

    Profiles of atmospheric temperature, humidity and ozone can be recovered from the thermal emission spectra in the interval 400 to 1,500 cm(-1) obtained from the Nimbus 4 satellite. The spectra can also be used to study surface restrahlen effects and other geophysical and meteorological phenomena.

  8. Wind tunnel experiments: cold-air pooling and atmospheric decoupling above a melting snow patch

    NASA Astrophysics Data System (ADS)

    Mott, R.; Paterna, E.; Horender, S.; Crivelli, P.; Lehning, M.

    2015-10-01

    The longevity of perennial snow fields is not fully understood but it is known that strong atmospheric stability and thus boundary layer decoupling limits the amount of (sensible and latent) heat that can be transmitted to the snow surface. The strong stability is typically caused by two factors, (i) the temperature difference between the (melting) snow surface and the near-surface atmosphere and (ii) cold-air pooling in topographic depressions. These factors are almost always a prerequisite for perennial snow fields to exist. For the first time, this contribution investigates the relative importance of the two factors in a controlled wind tunnel environment. Vertical profiles of sensible heat fluxes are measured using two-component hot wire and one-component cold-wire anemometry directly over the melting snow patch. The comparison between a flat snow surface and one that has a depression shows that atmospheric decoupling is strongly increased in the case of topographic sheltering but only for low to moderate wind speeds. For those conditions, the near-surface suppression of turbulent mixing was observed to be strongest and drainage flows were decoupled from the surface enhancing atmospheric stability and promoting the cold-air pooling over the single snow patch. Further work is required to systematically and quantitatively describe the flux distribution for varying terrain geometry, wind speeds and air temperatures.

  9. Satellite estimates of shortwave surface radiation and atmospheric meteorology for the BOREAS experiment region

    NASA Technical Reports Server (NTRS)

    Moats, C. D.; Whitlock, C. H.; Lecroy, S. R.; Dipasquale, R. C.

    1994-01-01

    This report provides background data for the Boreal Ecosystem Atmosphere Study (BOREAS) sites, including daily, seasonal, interannual, and spatial variability of shortwave (SW) radiation at the Earth's surface. This background data, from the Version 1.1 SW data set, was provided by the Surface Radiation Budget (SRB) Climatology Project established by the World Climate Research Program (WCRP).

  10. Sulfur in the early martian atmosphere revisited: Experiments with a 3-D Global Climate Model

    NASA Astrophysics Data System (ADS)

    Kerber, Laura; Forget, François; Wordsworth, Robin

    2015-11-01

    Volcanic SO2 in the martian atmosphere has been invoked as a way to create a sustained or transient greenhouse during early martian history. Many modeling studies have been performed to test the feasibility of this hypothesis, resulting in a range of conclusions, from highly feasible to highly improbable. In this study we perform a wide range of simulations using the 3-D Laboratoire de Météorologie Dynamique Generic Global Climate Model (GCM) in order to place earlier results into context and to explore the sensitivity of model outcomes to parameters such as SO2 mixing ratio, atmospheric H2O content, background atmospheric pressure, and aerosol size, abundance, and composition. We conclude that SO2 is incapable of creating a sustained greenhouse on early Mars, and that even in the absence of aerosols, local and daily temperatures rise above 273 K for only for limited periods with favorable background CO2 pressures. In the presence of even small amounts of aerosols, the surface is dramatically cooled for realistic aerosol sizes. Brief, mildly warm conditions require the co-occurrence of many improbable factors, while cooling is achieved for a wide range of model parameters. Instead of causing warming, sulfur in the martian atmosphere may have caused substantial cooling, leading to the end of clement climate conditions on early Mars.

  11. The Zugspitze radiative closure experiment: quantification of the near-infrared water vapor continuum from atmospheric measurements

    NASA Astrophysics Data System (ADS)

    Reichert, Andreas; Sussmann, Ralf; Rettinger, Markus

    2016-04-01

    Inaccuracies in the description of atmospheric radiative processes are among the major shortcomings of current climate models. Especially the contribution by water vapor, the primary greenhouse gas in the Earth's atmosphere, currently still lacks sufficiently accurate quantification. The main focus of our study is on the so-called water vapor continuum absorption in the near-infrared spectral range, which is of crucial importance for atmospheric radiative processes. To date, the quantification of this contribution originates exclusively from laboratory experiments which show contradictory results and whose findings are not unambiguously transferable to atmospheric conditions. The aim of the Zugspitze radiative closure study is therefore to obtain, to our knowledge for the first time, an exact characterization of the near-infrared water vapor continuum absorption using atmospheric measurements. This enables validation and, if necessary, improvements of the radiative transfer codes used in current climate models. The closure experiment comprises near-infrared spectral radiance measurements using a solar absorption FTIR spectrometer. These measurements are then compared to synthetic radiance spectra computed by means of a high-resolution radiative transfer model. The spectral residuals, i.e. the difference between measured and calculated spectral radiances can then be used to quantify errors in the description of water vapor absorption. Due to the extensive permanent instrumentation available at the Zugspitze observatory, the atmospheric state used as an input to the model calculations can be constrained with high accuracy. Additionally, we employ a novel radiometric calibration strategy for the solar FTIR spectral radiance measurements based on a combination of the Langley method and measurements of a medium-temperature blackbody source. These prerequisites enable accurate quantification of the water vapor continuum in the near-infrared spectral region, where

  12. The Structure of the Venus Neutral Atmosphere from the Radio Science Experiment VeRa on Venus Express

    NASA Astrophysics Data System (ADS)

    Tellmann, S. A.; Häusler, B.; Pätzold, M.; Bird, M. K.; Tyler, G. L.

    2007-12-01

    The Venus Express Radio Science Experiment VeRa is sounding the Venus neutral atmosphere and ionosphere using the spacecraft radio subsystem in the oneway radio link mode. An Ultrastable Oscillator (USO) provides a high quality onboard frequency reference source for the derivation of electron density profiles in the ionosphere and profiles of pressure, temperature and neutral number density of the neutral atmosphere. The measurement configuration allows an altitude resolution of only a few hundred metres from the cloud deck at about 40 km to approximately 100 km. Three occultation seasons could be covered in the first two years of the Venus Express mission resulting in a data set of about 140 profiles of the neutral atmosphere. The polar orbit of Venus Express provides the opportunity to study the atmosphere at all planetocentric latitudes under varying illumination conditions. Special attention will be given to day-night variations of the thermal structure and the temperature distribution at high polar latitudes on both hemispheres ("cold collar region") and signal absorption effects caused by the H2SO4 vapour.

  13. The role of soil moisture in land surface-atmosphere coupling: climate model sensitivity experiments over India

    NASA Astrophysics Data System (ADS)

    Williams, Charles; Turner, Andrew

    2015-04-01

    It is generally acknowledged that anthropogenic land use changes, such as a shift from forested land into irrigated agriculture, may have an impact on regional climate and, in particular, rainfall patterns in both time and space. India provides an excellent example of a country in which widespread land use change has occurred during the last century, as the country tries to meet its growing demand for food. Of primary concern for agriculture is the Indian summer monsoon (ISM), which displays considerable seasonal and subseasonal variability. Although it is evident that changing rainfall variability will have a direct impact on land surface processes (such as soil moisture variability), the reverse impact is less well understood. However, the role of soil moisture in the coupling between the land surface and atmosphere needs to be properly explored before any potential impact of changing soil moisture variability on ISM rainfall can be understood. This paper attempts to address this issue, by conducting a number of sensitivity experiments using a state-of-the-art climate model from the UK Meteorological Office Hadley Centre: HadGEM2. Several experiments are undertaken, with the only difference between them being the extent to which soil moisture is coupled to the atmosphere. Firstly, the land surface is fully coupled to the atmosphere, globally (as in standard model configurations); secondly, the land surface is entirely uncoupled from the atmosphere, again globally, with soil moisture values being prescribed on a daily basis; thirdly, the land surface is uncoupled from the atmosphere over India but fully coupled elsewhere; and lastly, vice versa (i.e. the land surface is coupled to the atmosphere over India but uncoupled elsewhere). Early results from this study suggest certain 'hotspot' regions where the impact of soil moisture coupling/uncoupling may be important, and many of these regions coincide with previous studies. Focusing on the third experiment, i

  14. Data for NASA's AVSSE 1 Experiment: 25 Mb Sounding Data and Synoptic Charts. [atmospheric variability and severe storm experiments

    NASA Technical Reports Server (NTRS)

    Fucik, N. F.; Turner, R. E.

    1976-01-01

    The AVSSE 1 Experiment is described and tabulated rawinsonde data at 25 mb intervals from the surface to 25 mb are presented for the 24 stations participating in the experiment. Soundings were taken between 1,200 GMT, April 27, and 1,200 GMT, April 28, 1975. The methods of data processing and accuracy are briefly discussed. Synoptic charts prepared from the data are presented, as well as an example of contact data.

  15. Studies of the differential absorption rocket experiment. [to measure atmospheric electron density

    NASA Technical Reports Server (NTRS)

    Ginther, J. C.; Smith, L. G.

    1975-01-01

    Investigations of the ionosphere, in the rocket program of the Aeronomy Laboratory, include a propagation experiment, the data from which may be analyzed in several modes. This report considers in detail the differential absorption experiment. The sources of error and limitations of sensitivity are discussed. Methods of enhancing the performance of the experiment are described. Some changes have been made in the system and the improvement demonstrated. Suggestions are made for further development of the experiment.

  16. Recherche et Analyse de Galaxies Brilliantes EN Exces EN Ultraviolet

    NASA Astrophysics Data System (ADS)

    Coziol, Roger

    Dans ce travail, nous decrivons et presentons les resultats du sondage Montreal Blue Galaxy (MBG) visant la recherche de galaxies emettant en exces en ultraviolet. Cette recherche utilise le materiel photographique du sondage MCT (Montreal-Cambridge-Tololo) qui par son etendue correspond a un des plus importants sondages de l'hemisphere austral. Le sondage MBG est presentement le seul dans cet hemisphere a employer la technique de poses multiples pour la selection de ses candidats. Grace a cette technique, nous avons l'occasion d'etudier un echantillon de galaxies ayant des caracteristiques quelque peu differentes de celles des echantillons analyses auparavant. Deux phenomenes peuvent expliquer l'exces d'ultraviolet observe dans ces galaxies. Le premier suppose la presence dans leur noyau d'un trou noir massif. Toutes les galaxies sujettes a ce type d'activite sont regroupees sous le nom de galaxies avec noyau actif (AGN). Le deuxieme phenomene est relie a une periode de formation intense d'etoiles, ou sursaut de formation d'etoiles ("starburst"). L'exces d'ultraviolet trahit ici la presence d'un grand nombre d'etoiles massives recemment creees au sein de ces galaxies. En plus d'augmenter le nombre d'AGN connues, les sondages de galaxies brillantes en ultraviolet permettent aussi d'approfondir les questions specifiques suivantes: combien y a-t'il de galaxies starbursts differentes? Quelle est l'origine possible de leur activite? Quel est le role des sursauts de formation d'etoiles dans la vie d'une galaxie? Quel est le lien entre les galaxies starbursts et les AGN?. L'analyse de notre echantillon de galaxies se fait par l'entremise de plusieurs methodes. La premiere consiste a obtenir des spectres optiques de nos candidats. L'etude de ces spectres nous permet de distinguer entre les AGN et les galaxies starbursts et de deduire plusieurs parametres physiques importants. Notre deuxieme methode consiste a obtenir des images. Ceci nous permet d'avoir une idee de la

  17. Exploring Atmospheric Aqueous Chemistry (and Secondary Organic Aerosol Formation) through OH Radical Oxidation Experiments, Droplet Evaporation and Chemical Modeling

    NASA Astrophysics Data System (ADS)

    Turpin, B. J.; Kirkland, J. R.; Lim, Y. B.; Ortiz-Montalvo, D. L.; Sullivan, A.; Häkkinen, S.; Schwier, A. N.; Tan, Y.; McNeill, V. F.; Collett, J. L.; Skog, K.; Keutsch, F. N.; Sareen, N.; Carlton, A. G.; Decesari, S.; Facchini, C.

    2013-12-01

    Gas phase photochemistry fragments and oxidizes organic emissions, making water-soluble organics ubiquitous in the atmosphere. My group and others have found that several water-soluble compounds react further in the aqueous phase forming low volatility products under atmospherically-relevant conditions (i.e., in clouds, fogs and wet aerosols). Thus, secondary organic aerosol can form as a result of gas followed by aqueous chemistry (aqSOA). We have used aqueous OH radical oxidation experiments coupled with product analysis and chemical modeling to validate and refine the aqueous chemistry of glyoxal, methylglyoxal, glycolaldehyde, and acetic acid. The resulting chemical model has provided insights into the differences between oxidation chemistry in clouds and in wet aerosols. Further, we conducted droplet evaporation experiments to characterize the volatility of the products. Most recently, we have conducted aqueous OH radical oxidation experiments with ambient mixtures of water-soluble gases to identify additional atmospherically-important precursors and products. Specifically, we scrubbed water-soluble gases from the ambient air in the Po Valley, Italy using four mist chambers in parallel, operating at 25-30 L min-1. Aqueous OH radical oxidation experiments and control experiments were conducted with these mixtures (total organic carbon ≈ 100 μM-C). OH radicals (3.5E-2 μM [OH] s-1) were generated by photolyzing H2O2. Precursors and products were characterized using electrospray ionization mass spectrometry (ESI-MS), ion chromatography (IC), IC-ESI-MS, and ultra high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Chemical modeling suggests that organic acids (e.g., oxalate, pyruvate, glycolate) are major products of OH radical oxidation at cloud-relevant concentrations, whereas organic radical - radical reactions result in the formation of oligomers in wet aerosols. Products of cloud chemistry and droplet evaporation have

  18. Remote probing of atmospheric particulates from radiation extinction experiments: A review of methods

    NASA Technical Reports Server (NTRS)

    Fymat, A. L.

    1976-01-01

    The existing methodology for reconstructing the particle size distribution and inferring the refractive index of absorbing and scattering atmospheric particulates is critically reviewed. Emphasis is placed on method capabilities and shortcomings and, wherever possible, on achievable accuracy. The nature of the associated remote probing problem is analyzed with regard to the effects of the particulates on EM wave propagation in the atmosphere. The parameterization of size distribution is studied within the unifying framework of Pearson's distribution curves. The inversions of extinction measurements and their ratios are considered separately, and the potentialities of each type of measurement are identified. Work lacking in each of the methods reviewed is indicated. A method of determining both the effective complex refractive index and size distribution model parameters from the same data is also presented. Lastly, determination from extinction ratio data of the complex refractive index independent of size distribution is discussed and error analyzed.

  19. An Overview of the Regional Experiments for Land-atmosphere Exchanges 2012 (REFLEX 2012) Campaign

    NASA Astrophysics Data System (ADS)

    Timmermans, Wim J.; van der Tol, Christiaan; Timmermans, Joris; Ucer, Murat; Chen, Xuelong; Alonso, Luis; Moreno, Jose; Carrara, Arnaud; Lopez, Ramon; de la Cruz Tercero, Fernando; Corcoles, Horacio L.; de Miguel, Eduardo; Sanchez, Jose A. G.; Pérez, Irene; Franch, Belen; Munoz, Juan-Carlos J.; Skokovic, Drazen; Sobrino, Jose; Soria, Guillem; MacArthur, Alasdair; Vescovo, Loris; Reusen, Ils; Andreu, Ana; Burkart, Andreas; Cilia, Chiara; Contreras, Sergio; Corbari, Chiara; Calleja, Javier F.; Guzinski, Radoslaw; Hellmann, Christine; Herrmann, Ittai; Kerr, Gregoire; Lazar, Adina-Laura; Leutner, Benjamin; Mendiguren, Gorka; Nasilowska, Sylwia; Nieto, Hector; Pachego-Labrador, Javier; Pulanekar, Survana; Raj, Rahul; Schikling, Anke; Siegmann, Bastian; von Bueren, Stefanie; Su, Zhongbo (Bob)

    2015-12-01

    The REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tiesas farm in an agricultural area in the south of Spain. During the period of ten days, measurements were made to capture the main processes controlling the local and regional land-atmosphere exchanges. Apart from multi-temporal, multi-directional and multi-spatial space-borne and airborne observations, measurements of the local meteorology, energy fluxes, soil temperature profiles, soil moisture profiles, surface temperature, canopy structure as well as leaf-level measurements were carried out. Additional thermo-dynamical monitoring took place at selected sites. After presenting the different types of measurements, some examples are given to illustrate the potential of the observations made.

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

    NASA Technical Reports Server (NTRS)

    1986-01-01

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

  1. VISSR Atmospheric Sounder (VAS) simulation experiment for a severe storm environment

    NASA Technical Reports Server (NTRS)

    Chesters, D.; Uccellini, L. W.; Mostek, A.

    1981-01-01

    Radiance fields were simulated for prethunderstorm environments in Oklahoma to demonstrate three points: (1) significant moisture gradients can be seen directly in images of the VISSIR Atmospheric Sounder (VAS) channels; (2) temperature and moisture profiles can be retrieved from VAS radiances with sufficient accuracy to be useful for mesoscale analysis of a severe storm environment; and (3) the quality of VAS mesoscale soundings improves with conditioning by local weather statistics. The results represent the optimum retrievability of mesoscale information from VAS radiance without the use of ancillary data. The simulations suggest that VAS data will yield the best soundings when a human being classifies the scene, picks relatively clear areas for retrieval, and applies a "local" statistical data base to resolve the ambiguities of satellite observations in favor of the most probable atmospheric structure.

  2. Absorption of solar radiation by the atmosphere as determined using satellite, aircraft, and surface data during the Atmospheric Radiation Measurement Enhanced Shortwave Experiment (ARESE)

    SciTech Connect

    Valero, Francisco P. J.; Minnis, Patrick; Pope, Shelly K.; Bucholtz, Anthony; Bush, Brett C.; Doelling, David R.; Smith, William L. Jr.; Dong, Xiquan

    2000-02-27

    Data sets acquired during the Atmospheric Radiation Measurement Enhanced Shortwave Experiment (ARESE) using simultaneous measurements from five independent platforms (GOES 8 geostationary satellite, ER-2, Egrett and Twin Otter aircraft, and surface) are analyzed and compared. A consistent data set can be built for selected days during ARESE on the basis of the observations from these platforms. The GOES 8 albedos agree with the ER 2, Egrett, and Twin Otter measured instantaneous albedos within 0.013{+-}0.016, 0.018{+-}0.032, and 0.006{+-}0.011, respectively. It is found that for heavy overcast conditions the aircraft measurements yield an absorptance of 0.32{+-}0.03 for the layer between the aircraft (0.5-13 km), while the GOES 8 albedo versus surface transmittance analysis gives an absorptance of 0.33{+-}0.04 for the total atmosphere (surface to top). The absorptance of solar radiation estimated by model calculations for overcast conditions varies between 0.16 and 0.24, depending on the model used and on cloud and aerosol implementation. These results are in general agreement with recent findings for cloudy skies, but here a data set that brings together independent simultaneous observations (satellite, surface, and aircraft) is used. Previous ARESE results are reexamined in light of the new findings, and it is concluded that the overcast absorptance in the 0.224-0.68 {mu}m spectral region ranges between 0.04{+-}0.06 and 0.08{+-}0.06, depending on the particular case analyzed. No evidence of excess clear-sky absorption beyond model and experimental errors is found. (c) 2000 American Geophysical Union.

  3. Smoke Plumes from Kuwaiti Oil Fires as Atmospheric Experiment of Opportunity: An Early Look

    DTIC Science & Technology

    1991-10-01

    1991 Final--March - October 1991 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Smoke Plumes From Kuwaiti Oil Fires as Atmospheric - MDA...phenomenology associated with the large number of oil fires lit by the Iraqi military in Kuwait in February 1991 , and which are probably the worst man-made air...Kuwaiti Oil Fires from Space Shuttle Photographs, 5-8 April 1991 (Source: Lulla and Helfert, 1991 ) 3 IRA 30ON I lo KUWAIT ’

  4. The Optical Profiling of the Atmospheric Limb (OPAL) CubeSat Experiment

    NASA Astrophysics Data System (ADS)

    Jeppesen, M.; Miller, J.; Cox, W.; Taylor, M. J.; Swenson, C.; Neilsen, T. L.; Fish, C. S.; Scherliess, L.; Christensen, A. B.; Cleave, M.

    2015-12-01

    The Earth's lower thermosphere is an important interface region between the neutral atmosphere and the "space weather" environment. While the high-latitude region of the thermosphere responds promptly to energy inputs, relatively little is known about the global/regional response to these energy inputs. Global temperatures are predicted to respond within 3-6 hours, but the details of the thermal response of the atmosphere as energy transports away from high-latitude source regions is not well understood. The Optical Profiling of the Atmospheric Limb (OPAL) mission aims to characterize this thermal response through observation of the temperature structure of the lower thermosphere at mid- and low-latitudes. The OPAL instrument is designed to map global thermospheric temperature variability over the critical "thermospheric gap" region (~100-140 km altitude) by spectroscopic analysis of molecular oxygen A-band emission (758 - 768 nm). The OPAL instrument is a grating-based imaging spectrometer with refractive optics and a high-efficiency volume holographic grating (VHG). The scene is sampled by 7 parallel slits that form non-overlapping spectral profiles at the focal plane with resolution of 0.5 nm (spectral), 1.5 km (limb profiling), and 60 km (horizontal sampling). A CCD camera at the instrument focal plane delivers low noise and high sensitivity. The instrument is designed to strongly reject stray light from daylight regions of the earth. The OPAL mission is funded by the National Science Foundation (NSF) CubeSat-based Science Missions for Geospace and Atmospheric Research program. The OPAL instrument, CubeSat bus and mission are being designed, built and executed by a team comprised of students and professors from Utah State University, Dixie State University and the University of Maryland Eastern Shore, with support from professional scientists and engineers from the Space Dynamics Laboratory and Hawk Institute for Space Science.

  5. Atmospheric effects in astroparticle physics experiments and the challenge of ever greater precision in measurements

    NASA Astrophysics Data System (ADS)

    Louedec, Karim

    2015-01-01

    Astroparticle physics and cosmology allow us to scan the universe through multiple messengers. It is the combination of these probes that improves our understanding of the universe, both in its composition and its dynamics. Unlike other areas in science, research in astroparticle physics has a real originality in detection techniques, in infrastructure locations, and in the observed physical phenomenon that is not created directly by humans. It is these features that make the minimisation of statistical and systematic errors a perpetual challenge. In all these projects, the environment is turned into a detector medium or a target. The atmosphere is probably the environment component the most common in astroparticle physics and requires a continuous monitoring of its properties to minimise as much as possible the systematic uncertainties associated. This paper introduces the different atmospheric effects to take into account in astroparticle physics measurements and provides a non-exhaustive list of techniques and instruments to monitor the different elements composing the atmosphere. A discussion on the close link between astroparticle physics and Earth sciences ends this paper.

  6. Atmospheric response in aurora experiment: Observations of E and F region neutral winds in a region of postmidnight diffuse aurora

    NASA Technical Reports Server (NTRS)

    Larsen, M. F.; Marshall, T. R.; Mikkelsen, I. S.; Emery, B. A.; Christensen, A.; Kayser, D.; Hecht, J.; Lyons, L.; Walterscheid, R.

    1995-01-01

    The goal of the Atmospheric Response in Aurora (ARIA) experiment carried out at Poker Flat, Alaska, on March 3, 1992, was to determine the response of the neutral atmosphere to the long-lived, large-scale forcing that is characteristic of the diffuse aurora in the post midnight sector. A combination of chemical release rocket wind measurements, instrumented rocket composition measurements, and ground-based optical measurements were used to characterize the response of the neutral atmosphere. The rocket measurements were made at the end of a 90-min period of strong Joule heating. We focus on the neutral wind measurements made with the rocket. The forcing was determined by running the assimilated mapping of ionospheric electrodynamics (AMIE) analysis procedure developed at the National Center for Atmospheric Research. The winds expected at the latitude and longitude of the experiment were calculated using the spectral thermospheric general circulation model developed at the Danish Meteorological Institute. Comparisons of the observations and the model suggest that the neutral winds responded strongly in two height ranges. An eastward wind perturbation of approximately 100 m/s developed between 140 and 200 km altitude with a peak near 160 km. A southwestward wind with peak magnitude of approximately 150 m/s developed near 115 km altitude. The large amplitude winds at the lower altitude are particularly surprising. They appear to be associated with the upward propagating semidiurnal tide. However, the amplitude is much larger than predicted by any of the tidal models, and the shear found just below the peak in the winds was nominally unstable with a Richardson number of approximately 0.08.

  7. Atmospheric response in aurora experiment: Observations of E and F region neutral winds in a region of postmidnight diffuse aurora

    SciTech Connect

    Larsen, M.F.; Marshall, T.R.; Mikkelsen, I.S.; Emery, B.A.; Christensen, A.; Kayser, D.; Hecht, J.; Lyons, L.; Walterscheid, R.

    1995-11-01

    The goal of the Atmospheric Response in Aurora (ARIA) experiment carried out at Poker Flat, Alaska, on March 3, 1992, was to determine the response of the neutral atmosphere to the long-lived, large-scale forcing that is characteristic of the diffuse aurora in the post midnight sector. A combination of chemical release rocket wind measurements, instrumented rocket composition measurements, and ground-based optical measurements were used to characterize the response of the neutral atmosphere. The rocket measurements were made at the end of a 90-min period of strong Joule heating. The authors focus on the neutral wind measurements made with the rocket. The forcing was determined by running the assimilated mapping of ionospheric electrodynamics (AMIE) analysis procedure developed at the National Center for Atmospheric Research. The winds expected at the latitude and longitude of the experiment were calculated using the spectral thermospheric general circulation model developed at the Danish Meteorological Institute. Comparisons of the observations and the model suggest that the neutral winds responded strongly in two height ranges. An eastward wind perturbation of approximately 100 m/s developed between 140 and 200 km altitude with a peak near 160 km. A southwestward wind with peak magnitude of approximately 150 m/s developed near 115 km altitude. The large amplitude winds at the lower altitude are particularly surprising. They appear to be associated with the upward propagating semidiurnal tide. However, the amplitude is much larger than predicted by any of the tidal models, and the shear found just below the peak in the winds was nominally unstable with a Richardson number of approximately 0.08.

  8. Atmospheric response in aurora experiment: Observations of E and F region neutral winds in a region of postmidnight diffuse aurora

    SciTech Connect

    Larsen, M.F.; Marshall, T.R.; Mikkelsen, I.S.

    1995-09-01

    The goal of the Atmospheric Response in Aurora (ARIA) experiment carried out at Poker Flat, Alaska, on March 3, 1992, was to determine the response of the neutral atmosphere to the long-lived, large-scale forcing that is characteristic of the diffuse aurora in the postmidnight sector. A combination of chemical release rocket wind measurements, intrumented rocket composition measurements, and ground-based optical measurements were used to characterize the response of the neutral atmosphere. The rocket measurements were made at the end of a 90-min period of strong Joule heating. We focus on the neutral wind measurements made with the rocket. The forcing was determined by running the assimilated mapping of ionospheric electrodynamics (AMIE) analysis procedure developed at the National Center for Atmospheric Research. The winds expected at the latitude and longitude of the experiment were calculated using the spectral thermospheric general circulation model developed at the Danish Meteorological Institute. Comparisons of the observations and the model suggest that the neutral winds responded strongly in two height ranges. An eastward wind perturbation of {approximately}100 m s{sup -1} developed between 140 and 200 km altitude with a peak near 160 km. A southwestward wind with peak magnitude of {approximately}150 m s{sup -1} developed near 115 km altitude. The large amplitude winds at the lower altitude are particularly surprising. They appear to be associated with the upward propagating semidiurnal tide. However, the amplitude is much larger than predicted by any of the tidal models, and the shear found just below the peak in the winds was nomially unstable with a Richardson number of {approximately}0.08. 17 refs., 12 figs.

  9. Les enjuex éthiques entourant la recherche en santé sur les enfants

    PubMed Central

    2008-01-01

    RÉSUMÉ La recherche en santé est un devoir moral parce qu’elle est la base des soins probants prodigués par tous les dispensateurs de soins. Des politiques et des règlements précis régissent la tenue des recherches sur des humains. Il faut procéder à une évaluation éthique d’un projet de recherche donné avant de pouvoir l’entreprendre. La recherche sur les enfants pose d’énormes défis en matière de consentement éclairé et d’assentiment, de vulnérabilité et de potentiel de conflit d’intérêts (CDI). Les chercheurs en santé pédiatrique devraient prôner la participation des enfants à la recherche, tout en se montrant attentifs à en limiter les risques.

  10. The atmospheric inventory of Xenon and noble cases in shales The plastic bag experiment

    NASA Technical Reports Server (NTRS)

    Bernatowicz, T. J.; Podosek, F. A.; Honda, M.; Kramer, F. E.

    1984-01-01

    A novel trapped gas analysis protocol is applied to five shales in which the samples are sealed in air to eliminate the possibility of gas loss in the preanalysis laboratory vacuum exposure of a conventional protocol. The test is aimed at a determination concerning the hypothesis that atmospheric noble gases occur in the same proportion as planetary gases in meteorites, and that the factor-of-23 deficiency of air Xe relative to planetary Xe is made up by Xe stored in shales or other sedimentary rocks. The results obtained do not support the shale hypothesis.

  11. The atmospheric inventory of Xenon and noble cases in shales The plastic bag experiment

    NASA Technical Reports Server (NTRS)

    Bernatowicz, T. J.; Podosek, F. A.; Honda, M.; Kramer, F. E.

    1984-01-01

    A novel trapped gas analysis protocol is applied to five shales in which the samples are sealed in air to eliminate the possibility of gas loss in the preanalysis laboratory vacuum exposure of a conventional protocol. The test is aimed at a determination concerning the hypothesis that atmospheric noble gases occur in the same proportion as planetary gases in meteorites, and that the factor-of-23 deficiency of air Xe relative to planetary Xe is made up by Xe stored in shales or other sedimentary rocks. The results obtained do not support the shale hypothesis.

  12. Experiments in monthly mean simulation of the atmosphere with a coarse-mesh general circulation model

    NASA Technical Reports Server (NTRS)

    Lutz, R. J.; Spar, J.

    1978-01-01

    The Hansen atmospheric model was used to compute five monthly forecasts (October 1976 through February 1977). The comparison is based on an energetics analysis, meridional and vertical profiles, error statistics, and prognostic and observed mean maps. The monthly mean model simulations suffer from several defects. There is, in general, no skill in the simulation of the monthly mean sea-level pressure field, and only marginal skill is indicated for the 850 mb temperatures and 500 mb heights. The coarse-mesh model appears to generate a less satisfactory monthly mean simulation than the finer mesh GISS model.

  13. Natural variability of tropical upper stratospheric ozone inferred from the Atmosphere Explorer backscatter ultraviolet experiment

    NASA Technical Reports Server (NTRS)

    Frederick, J. E.; Abrams, R. B.; Dasgupta, R.; Guenther, B.

    1981-01-01

    Analysis of backscattered ultraviolet radiances observed at tropical latitudes by the Atmosphere Explorer-E satellite reveals both annual and semiannual cycles in upper stratospheric ozone. The annual variation dominates the signal at wavelengths which sense ozone primarily above 45 km while below this, to the lowest altitude sensed, 35 km, the semiannual component has comparable amplitude. Comparison of radiance measurements taken with the same instrument at solar minimum during 1976 and solar maximum in 1979 show no significant differences. This suggests that variations in upper stratospheric ozone over the solar cycle are small, although the data presently available do not allow a definite conclusion.

  14. A rotating annulus driven by localized convective forcing: a new atmosphere-like experiment

    NASA Astrophysics Data System (ADS)

    Scolan, Hélène; Read, Peter L.

    2017-06-01

    We present an experimental study of flows in a cylindrical rotating annulus convectively forced by local heating in an annular ring at the bottom near the external wall and via a cooled circular disk near the axis at the top surface of the annulus. This new configuration is distinct from the classical thermally driven annulus analogue of the atmosphere circulation, in which thermal forcing is applied uniformly on the sidewalls, but with a similar aim to investigate the baroclinic instability of a rotating, stratified flow subjected to zonally symmetric forcing. Two vertically and horizontally displaced heat sources/sinks are arranged, so that in the absence of background rotation, statically unstable Rayleigh-Bénard convection would be induced above the source and beneath the sink, thereby relaxing strong constraints placed on background temperature gradients in previous experimental configurations based on the conventional rotating annulus. This better emulates local vigorous convection in the tropics and polar regions of the atmosphere while also allowing stably-stratified baroclinic motion in the central zone of the annulus, as in mid-latitude regions in the Earth's atmosphere. Regimes of flow are identified, depending mainly upon control parameters that in turn depend on rotation rate and the strength of differential heating. Several regimes exhibit baroclinically unstable flows which are qualitatively similar to those previously observed in the classical thermally driven annulus. However, in contrast to the classical configuration, they typically exhibit more spatio-temporal complexity. Thus, several regimes of flow demonstrate the equilibrated co-existence of, and interaction between, free convection and baroclinic wave modes. These new features were not previously observed in the classical annulus and validate the new setup as a tool for exploring fundamental atmosphere-like dynamics in a more realistic framework. Thermal structure in the fluid is

  15. The Atmospheric Trace Molecule Spectroscopy (ATMOS) Experiment: Deployment on the ATLAS Space Shuttle Missions

    NASA Technical Reports Server (NTRS)

    Gunson, M. R.; Abbas, M. M.; Abrams, M. C.; Allen, M.; Brown, L. R.; Brown, T. L.; Chang, A. Y.; Goldman, A.; Irion, F. W.; Lowes, L. L..; Mahieu, E.; Manney, G. L.; Michelsen, H. A.; Newchurch, M. J.; Rinsland, C. P.; Salawitch, R. J.; Stiller, G. P.; Toon, G. C.; Yung, Y. L.; Zander, R.

    1996-01-01

    The ATMOS Fourier transform spectrometer was flown for a fourth time on the Space Shuttle as part of the ATLAS-3 instrument payload in November 1994. More than 190 sunrise and sunset occultation events provided measurements of more than 30 atmospheric trace gases at latitudes 3 - 49 deg N and 65 - 72 deg S, including observations both inside and outside the Antarctic polar vortex. The instrument configuration, data retrieval methodology, and mission background are described to place in context analyses of ATMOS data presented in this issue.

  16. Three atmospheric dispersion experiments involving oil fog plumes measured by lidar

    NASA Technical Reports Server (NTRS)

    Eberhard, W. L.; Mcnice, G. T.; Troxel, S. W.

    1986-01-01

    The Wave Propagation Lab. participated with the U.S. Environmental Protection Agency in a series of experiments with the goal of developing and validating dispersion models that perform substantially better that models currently available. The lidar systems deployed and the data processing procedures used in these experiments are briefly described. Highlights are presented of conclusions drawn thus far from the lidar data.

  17. Investigation of the external flow analysis for density measurements at high altitude. [shuttle upper atmosphere mass spectrometer experiment

    NASA Technical Reports Server (NTRS)

    Bienkowski, G. K.

    1983-01-01

    A Monte Carlo program was developed for modeling the flow field around the space shuttle in the vicinity of the shuttle upper atmosphere mass spectrometer experiment. The operation of the EXTERNAL code is summarized. Issues associated with geometric modeling of the shuttle nose region and the modeling of intermolecular collisions including rotational energy exchange are discussed as well as a preliminary analysis of vibrational excitation and dissociation effects. The selection of trial runs is described and the parameters used for them is justified. The original version and the modified INTERNAL code for the entrance problem are reviewed. The code listing is included.

  18. The Titan Haze Simulation Experiment: Probing the Different Steps of Titan’s Atmospheric Chemistry at Low Temperature

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, Ella; Contreras, C. S.; Ricketts, C. L.; Salama, F.

    2012-10-01

    In Titan’s atmosphere, a complex chemistry between its two main constituents, N2 and CH4, leads to the production of heavy molecules and subsequently to solid aerosols. The Titan Haze Simulation (THS) experiment has been developed on the Ames simulation chamber, COSmIC, to study the chemical pathways that link the simple molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN...) to benzene, and to polycyclic aromatic hydrocarbons (PAHs) and nitrogen-containing PAHs (PANHs) as precursors to the production of solid aerosols. In the THS experiment, Titan’s atmospheric chemistry is simulated by plasma in the stream of a supersonic expansion. With this unique design, the gas mixture is cooled to Titan-like temperature ( 150K) before inducing the chemistry by plasma discharge. Different gas mixtures containing N2, CH4, and the first products of Titan’s chemistry but also much heavier molecules like PAHs or PANHs can be injected to study specific chemical reactions. The products of the chemistry are detected and studied using two complementary techniques: Cavity Ring Down Spectroscopy and Time-Of-Flight Mass Spectrometry. Thin tholin deposits are also produced in the THS experiment and can be analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and Scanning Electron Microscopy (SEM). Here we present the results of a systematic mass spectrometry study using different gas mixtures of N2 with hydrocarbon precursors, and similar mixtures with N2-CH4 (90:10) instead of pure N2, to study specific pathways associated with the presence of these trace elements in Titan’s atmosphere. These results show the uniqueness of the THS experiment to help understand the first steps of Titan’s atmospheric chemistry as well as intermediate steps of the chemistry and specific chemical pathways leading to Titan’s haze formation. We will also present preliminary results of the tholin ex situ analysis and discuss the implications for our understanding of

  19. An investigation of geometry and noise corrections to San Marco-C neutral atmospheric composition experiment data

    NASA Technical Reports Server (NTRS)

    Curtis, S. A.

    1972-01-01

    The problem of the calculation of ambient densities from San Marco-C neutral atmospheric composition experiment data is considered. A brief description is given of the data measurement method, followed by a description of both the theoretical and experimental data curves. Geometry, electrometer distortions, and noise effects are then studied in terms of their effects on the ideal data form. From these considerations two data reduction methods are evolved. The first is an iterative integration technique that exploits the symmetry of the experimental data about the minimum angle of attack. For the analysis of geometry effects, a second method using interval averaging was developed and studied.

  20. The seasonal and global behavior of water vapor in the Mars atmosphere - Complete global results of the Viking atmospheric water detector experiment

    NASA Technical Reports Server (NTRS)

    Jakosky, B. M.; Farmer, C. B.

    1982-01-01

    A key question regarding the evolution of Mars is related to the behavior of its volatiles. The present investigation is concerned with the global and seasonal abundances of water vapor in the Mars atmosphere as mapped by the Viking Mars Atmospheric Water Detector (MAWD) instrument for almost 1-1/2 Martian years from June 1976 to April 1979. Attention is given to the implications of the observed variations for determining the relative importance of those processes which may be controlling the vapor cycle on a seasonal basis. The processes considered include buffering of the atmosphere water by a surface or subsurface reservior of ground ice, physically adsorbed water, or chemically bound water. Other processes are related to the supply of water from the residual or seasonal north polar ice cap, the redistribution of the vapor resulting from atmospheric circulation, and control of the vapor holding capacity of the atmosphere by the local atmospheric temperatures.

  1. The seasonal and global behavior of water vapor in the Mars atmosphere - Complete global results of the Viking atmospheric water detector experiment

    NASA Technical Reports Server (NTRS)

    Jakosky, B. M.; Farmer, C. B.

    1982-01-01

    A key question regarding the evolution of Mars is related to the behavior of its volatiles. The present investigation is concerned with the global and seasonal abundances of water vapor in the Mars atmosphere as mapped by the Viking Mars Atmospheric Water Detector (MAWD) instrument for almost 1-1/2 Martian years from June 1976 to April 1979. Attention is given to the implications of the observed variations for determining the relative importance of those processes which may be controlling the vapor cycle on a seasonal basis. The processes considered include buffering of the atmosphere water by a surface or subsurface reservior of ground ice, physically adsorbed water, or chemically bound water. Other processes are related to the supply of water from the residual or seasonal north polar ice cap, the redistribution of the vapor resulting from atmospheric circulation, and control of the vapor holding capacity of the atmosphere by the local atmospheric temperatures.

  2. Forecast experiments with the Community Atmospheric Model (CAM) over the Tropical Warm Pool - International Cloud Experiment (TWP-ICE)

    NASA Astrophysics Data System (ADS)

    Boyle, J. S.; Klein, S.

    2008-12-01

    The Tropical Warm Pool International Cloud Experiment (TWP-ICE) experiment took place over 20 January 2006 to 14 February 2006 centered on Darwin, Australia. The motivation behind the design of the observations for TWP-ICE was to better understand the factors that control tropical convection. Additionally, the experiment sought to describe how the characteristics of the convection affect the microphysics of the clouds, particularly the deep convective anvils and tropical cirrus. A chief goal of the TWP-ICE was to provide information of the tropical processes for the improvement of the parameterization of clouds in numerical weather prediction (NWP) and climate models. The TWP-ICE experiment combined aspects of previous observational campaigns, specifically the combination of a dense rawindsonde network, high altitude aircraft sampling and airborne and ground based radar and lidar also observations from geostationary and polar obrbiting satellites were used. The CAM experiments consisted of changing the cloud microphysics parameterizations and running with three different horizontal resolutions. The CAM simulations were performed using the finite volume dynamical core with grids of 1.9° x 2.5°, 0.9° x 1.25° and 0.47° x 0.63°. The cloud microphysics parameterizations used were the default CAM single moment scheme and a new double moment parameterization that predicts both the number and mass of liquid and ice condensate.The model was initialized by the state variables (wind, temperature, moisture and surface pressure) taken from the ECMWF operational analyses. The forecasts are for 5 days starting at 00Z. The results presented will focus on the short term day 1 ( 24-48h) of the forecasts. The validation of cloud properities requires the coordination of several different observational platforms, including the a millimeter Cloud radar and microwave radiometer at Darwin as well as rawindsondes. The new microphysics scheme produces better estimates of the cloud

  3. Low-energy-electron interactions with DNA: approaching cellular conditions with atmospheric experiments

    NASA Astrophysics Data System (ADS)

    Alizadeh, Elahe; Sanche, Léon

    2014-04-01

    A novel technique has been developed to investigate low energy electron (LEE)-DNA interactions in the presence of small biomolecules (e.g., N2, O2, H2O) found near DNA in the cell nucleus, in order to simulate cellular conditions. In this technique, LEEs are emitted from a metallic surface exposed by soft X-rays and interact with DNA thin films at standard ambient temperature and pressure (SATP). Whereas atmospheric N2 had little effect on the yields of LEE-induced single and double strand breaks, both O2 and H2O considerably modified and increased such damage. The highest yields were obtained when DNA is embedded in a combined O2 and H2O atmosphere. In this case, the amount of additional double strand breaks was supper-additive. The effect of modifying the chemical and physical stability of DNA by platinum-based chemotherapeutic agents (Pt-drugs) including cisplatin, carboplatin and oxaliplatin was also investigated with this technique. The results obtained provide information on the role played by subexcitation-energy electrons and dissociative electron attachment in the radiosensitization of DNA by Pt-drugs, which is an important step to unravel the mechanisms of radiosensitisation of these agents in chemoradiation cancer therapy.

  4. COOP 3D ARPA Experiment 109 National Center for Atmospheric Research

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Coupled atmospheric and hydrodynamic forecast models were executed on the supercomputing resources of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado and the Ohio Supercomputing Center (OSC)in Columbus, Ohio. respectively. The interoperation of the forecast models on these geographically diverse, high performance Cray platforms required the transfer of large three dimensional data sets at very high information rates. High capacity, terrestrial fiber optic transmission system technologies were integrated with those of an experimental high speed communications satellite in Geosynchronous Earth Orbit (GEO) to test the integration of the two systems. Operation over a spacecraft in GEO orbit required modification of the standard configuration of legacy data communications protocols to facilitate their ability to perform efficiently in the changing environment characteristic of a hybrid network. The success of this performance tuning enabled the use of such an architecture to facilitate high data rate, fiber optic quality data communications between high performance systems not accessible to standard terrestrial fiber transmission systems. Thus obviating the performance degradation often found in contemporary earth/satellite hybrids.

  5. Atmospheric entry simulations of Mars lander bioload--experiments in support of Beagle 2.

    PubMed

    Sancisi-Frey, Suzanne; Spry, J Andy; Garry, James; Pillinger, Judith M

    2006-01-01

    Simulations of the temperature and vacuum effects of Martian atmospheric entry upon Bacillus atrophaeus (formerly Bacillus subtilis var niger; 8058; NCIMB) endospores were carried out inside a purpose-built vacuum chamber. The work formed part of the study in support of planetary protection for the Beagle 2 Mars lander and investigated to what extent the outer surface of the lander's back heat shield would be sterilised during Mars atmospheric entry. The spores were heated to peak temperatures up to 300 degrees C over 30 s under vacuum conditions (10(-3) mbar). There was no effect on spore viability until peak temperatures reached 180-200 degrees C (12-15 s of heat exposure). Spore viability then fell rapidly with increasing temperature. Once peak temperatures exceeded 300 degrees C, no further spore viability was detected. The average heating rate was rapid (10 degrees C s(-1)); thus spores were exposed to peak temperatures for less than a second. These data inform on the process of determining bioburden reduction and control steps necessary for external surfaces of spacecraft which are non-sterile at launch, as well as providing new information about the ability of a model resistant organism to survive rapid, short-duration heating.

  6. The Atmospheric Lifetime Experiment. IV - Results for CF2Cl2 based on three years data

    NASA Technical Reports Server (NTRS)

    Cunnold, D. M.; Alyea, F. N.; Cardelino, C. A.; Prinn, R. G.; Rasmussen, R. A.; Crawford, A. J.; Simmonds, P. G.

    1983-01-01

    Observations of dichlorodifluoromethane obtained several times daily over the period July 1978 to June 1981 at Adrigole, Ireland (52 deg N, 10 deg W), Ragged Point, Barbados (13 deg N, 59 deg W), Point Matatula, American Samoa (14 deg S, 171 deg W), and Cape Grim, Tasmania (41 deg S, 145 deg E), are reported. Observations at Cape Meares, Oregon (45 deg N, 124 deg W), are also given for the period November 1980 to June 1981. On January 1, 1980, the average mixing ratio of dichlorodifluoromethane in the lower troposphere is estimated to have been 285 pptv and to have been increasing at 6.0 percent/year. The atmospheric lifetime of this compound is estimated from this data by adjusting its destruction rate in a two-dimensional model of the atmosphere so as to provide the best fit to the observations. Assuming destruction of CF2Cl2 in the stratosphere only, the lifetime estimate for January 1, 1980, by the inventory technique is 69 + 36 or - 18 years. The trend technique principally provides a lower limit to the lifetime of 81 years. The results suggest a need for further assessment of dichlorodifluoromethane release estimates, particularly those from the USSR and eastern Europe.

  7. Sulfur in the Early Martian Atmosphere Revisited: Experiments with a 3-D Global Climate Model

    NASA Astrophysics Data System (ADS)

    Kerber, L.; Forget, F.; Wordsworth, R.

    2013-09-01

    Data returned from the surface of Mars during the 1970s revealed intriguing geological evidence for a warmer and wetter early martian climate. Dendritic valley networks were discovered by Mariner 9 on ancient Noachian terrain [1], indicating that liquid water had flowed across the surface in the distant past. Since this time, geological investigations into early Martian history have attempted to ascertain the nature and level of activity of the early Martian hydrological cycle [e.g. 2-5] while atmospheric modeling efforts have focused on how the atmosphere could be warmed to temperatures great enough to sustain such activity [see 6-7 for reviews]. Geological and spectroscopic investigations have refined the history and chronology of Noachian Mars over time, and circulation of liquid water has been invoked to explain several spatially and temporally distinct morphological and chemical signatures found in the geological record. Detections of iron and magnesium-rich clays are widespread in the oldest Martian terrains, suggesting a period of pH-neutral aqueous alteration [e.g., 8]. Valley network incision also took place during the Noachian period [9]. Some chains of river valleys and craters lakes extend for thousands of kilometers, suggesting temperatures at least clement enough for sustained ice-covered flow [3,10]. The commencement of valley network incision is not well constrained, but the period of Mg/Fe clay formation appears to have ended before the termination of valley network formation, as the visible fluvial systems appear to have remobilized existing clays rather than forming them [5,8]. There is also evidence that the cessation of valley network formation was abrupt [11]. Towards the end of the Noachian, erosion rates appear to have been significantly higher than during subsequent periods, a process that has also been attributed to aqueous processes [12]. A period of sulfate formation followed, likely characterized by acidic, evaporitic playa environments

  8. Geographical, biological and remote sensing aspects of the Hydrologic Atmospheric Pilot Experiment in the Sahel (HAPEX-Sahel)

    SciTech Connect

    Prince, S.D.; Kerr, Y.H.; Goutorbe, J.P.

    1995-01-01

    HAPEX Sahel (Hydrological Atmospheric Pilot Experiment in the Sahel) was an international program focused on the soil-plant-atmosphere energy, water and carbon balance in the west African Sahel. It was intended to improve their understanding of the interaction between the Sahel and the general atmospheric circulation, both at present and in the future, providing a base line for studies of climate change. It was carried out in a 1{degree} x 1{degree} area of west Niger over a 3--4 year period with an 8-week intensive observation period from August to October 1992. HAPEX-Sahel was funded by a wise range of agencies in seven participating countries. Over 170 scientists visited and worked in the field. An interdisciplinary approach was adopted with contributed studies in hydrology and soil moisture, surface fluxes and vegetation, remote sensing science, and meteorology and mesoscale modeling. Detailed field measurements were concentrated at 3 ``supersites`` and 3 ancillary sites. Four aircraft were used for remote sensing and flux measurement. Observations from space were acquired from nine sensors on seven different satellite platforms. Conditions in 1992 turned out to be average for the last decade with good gradients of precipitation and a variety of vegetation productivities between the study sites. An information system has been established to provide a data base to disseminate the measurements. An active program of meetings, workshops, and interdisciplinary studies is now in progress.

  9. The Structure of the Venus Neutral Atmosphere from the Radio Science Experiment VeRa on Venus Express

    NASA Astrophysics Data System (ADS)

    Tellmann, S.; Häusler, B.; Pätzold, M.; Bird, M.; Tyler, G. L.

    2008-09-01

    The Venus Express Radio Science Experiment VeRa uses one-way radio signals at X-band (8.4 GHz) and S-band (2.3 GHz) for the sounding of the Venus neutral atmosphere and ionosphere. Three occultation seasons could be covered during the nominal mission of Venus Express resulting in a data set of about 118 profiles of the neutral atmosphere. Another three occultation seasons are planned during the extended mission. The polar orbit of Venus Express provides the opportunity to study the atmosphere at a large range of planetocentric latitudes under varying illumination conditions. Radial profiles of neutral number density derived from the occultations cover the altitude range 40-90 km, which are converted to vertical profiles of temperature and pressure. Profiles of static stability are found to be latitude-dependent and nearly adiabatic in the middle cloud region. Below the clouds the stability decreases at high latitudes. A large equator-to-pole temperature contrast of approximately 30 K is found at the 1-bar level. A distinct cold collar region could be observed on both hemispheres. At the latitudes of the cold collars, the tropopause altitude increases relative to higher and lower latitudes, while the temperature drops roughly 60 K. The observations indicate the existence of a wave number 2 structure polewards of ±75° latitude at altitudes of about 60 km.

  10. The Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Project: Overview and results from ten years of ACE operations

    NASA Astrophysics Data System (ADS)

    Walker, Kaley; Strong, Kimberly

    2014-05-01

    As of February 2014, the Canadian-led Atmospheric Chemistry Experiment (ACE) satellite mission has been making measurements of the Earth's atmosphere for ten years. As ACE operations have extended beyond the initial two-year mission, there is a continuing need to validate the trace gas data products from the ACE-Fourier Transform Spectrometer (ACE-FTS) and the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO) instruments. Ground-based measurements provide critical data for the validation of satellite retrievals of trace gases and for the assessment of long-term stability of these measurements. In particular, validation comparisons are needed for ACE during Arctic springtime to understand better the measurements of species involved in stratospheric ozone chemistry. To this end, eleven Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns have been conducted during the spring period (February - April in 2004 - 2014) at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Nunavut (80°N, 86°W). This period coincides with the most chemically active time of year in the Arctic, as well as a significant number of satellite overpasses. A suite of as many as 12 ground-based instruments, as well as frequent balloon-borne ozonesonde and radiosonde launches, have been used in each campaign. These instruments include: a ground-based version of the ACE-FTS (PARIS - Portable Atmospheric Research Interferometric Spectrometer), a terrestrial version of the ACE-MAESTRO, a SunPhotoSpectrometer, two zenith-viewing UV-visible grating spectrometers, a Bomem DA8 Fourier transform spectrometer, a Bruker 125HR Fourier transform spectrometer, a Systeme d'Analyse par Observations Zenithales (SAOZ) instrument, and several Brewer spectrophotometers. In the past several years, these results have been used to validate the measurements by the ACE-FTS and ACE-MAESTRO instruments on SCISAT as well

  11. Atmospheric turbulence in urban environments: large-eddy simulation and experiment

    NASA Astrophysics Data System (ADS)

    Hertwig, D.; Nguyen van yen, R.; Patnaik, G.; Leitl, B.

    2012-04-01

    The description of atmospheric turbulence in densely built urban environments is a major theoretical challenge, which has wide-ranging practical implications - regarding for example pollutant dispersion, wind comfort, and many other micro-climatic issues. The traditional approach to adopt obstacle-resolving micro-scale meteorological models based on Reynolds-averaged equations is strongly limited by its inherent inability to provide spatio-temporal data. Although more advanced models, such as large-eddy simulation (LES), are now technically applicable to this problem, the precise validation of their output is still a matter of ongoing investigation, which is particularly challenging due to the time-dependent nature of the problem. In this work, we undertake a systematic comparison between results of urban LES computations and boundary-layer wind-tunnel measurements of turbulent flow in the inner city of Hamburg, Germany. The experimental data were acquired for neutral atmospheric stratification within an urban model on a scale of 1:350, under well-defined and documented boundary constraints. Background information about the atmospheric inflow conditions for both the physical and numerical model was deduced from suburban field site measurements. LES computations were conducted by the U.S. Naval Research Laboratory using the code FAST3D-CT that is based on the monotone integrated LES methodology (MILES). The validation focuses on the comparison of time-series information and the characterization of turbulent flow structures within and above the urban canopy. Densely spaced measurements in vertical profiles and horizontal flow layers allow for the investigation of the urban boundary-layer development across the city. Typical obstacle-induced urban flow scenarios provide further test cases for detailed analyses. Besides mean flow and turbulence statistics, velocity histograms, fluctuation time scales, spectral information and statistics of the Reynolds stress

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  13. Atmospheric Radiation Measurment (ARM) Data from the Ganges Valley, India for the Ganges Valley Aerosol Experiment (GVAX)

    DOE Data Explorer

    In 2011 and 2012, the Ganges Valley Aerosol Experiment (GVAX) began in the Ganges Valley region of India. The objective was to obtain measurements of clouds, precipitation, and complex aerosols to study their impact on cloud formation and monsoon activity in the region. During the Indian Ocean Experiment (INDOEX) field studies, aerosols from the Ganges Valley region were shown to affect cloud formation and monsoon activity over the Indian Ocean. The complex field study used the ARM Mobile Facility (AMF) to measure radiative, cloud, convection, and aerosol characteristics over the mainland. The resulting data set captured pre-monsoon to post-monsoon conditions to establish a comprehensive baseline for advancements in the study of the effects of atmospheric conditions of the Ganges Valley.

  14. Atmospheric Background Measurement in the 300-400 nm Band with a Balloon Borne Experiment During a Nocturnal Flight

    NASA Astrophysics Data System (ADS)

    La Rosa, Giovanni; Agnetta, Gaetano; Biondo, Benedetto; Catalano, Osvaldo; Celi, Filippo; Di Raffaele, Renato; Giarrusso, Salvatore; Mangano, Angelo; Russo, Francesco; Linsley, John; Lo Bue, Angelo

    2001-03-01

    The balloon borne experiment, named BABY (BAckground BYpass) belongs to a wider program, AIRWATCH-OWL, intended for the observation of high energy Cosmic Rays from space, detecting the faint UV fluorescence light emitted by the atmospheric Nitrogen as final result of a complex hadronic cascade. In this framework, one of the fundamental information concern the knowledge of the background level. This is one of the main parameters that contribute to the sensitivity of any kind of instrument. The apparatus used for the BABY experiment was designed and completely built at the IFCAI-CNR in Palermo. The instrument is composed by two filtered and collimated photomultipliers (PMT) that detect the UV light in the 300-400 nm wavelength. We report a brief description of the design of the detector and the results coming from a preliminary analysis of the data taken during a nocturnal over-sea observation.

  15. Data for first NASA Atmospheric Variability Experiment (AVE 1). Part 1: Data tabulation. [rawindsonde data for eastern United States

    NASA Technical Reports Server (NTRS)

    Scoggins, J. R.; Smith, O. E.

    1973-01-01

    A tablulation is given of rawinsonde data for NASA's first Atmospheric Variability Experiment (AVE 1) conducted during the period February 19-22, 1964. Methods of data handling and processing, and estimates of error magnitudes are also given. Data taken on the AVE 1 project in 1964 enabled an analysis of a large sector of the eastern United States on a fine resolution time scale. This experiment was run in February 1964, and data were collected as a wave developed in the East Gulf on a frontal system which extended through the eastern part of the United States. The primary objective of AVE 1 was to investigate the variability of parameters in space and over time intervals of three hours, and to integrate the results into NASA programs which require this type of information. The results presented are those from one approach, and represent only a portion of the total research effort that can be accomplished.

  16. Dependence of the muon intensity on the atmospheric temperature measured by the GRAPES-3 experiment

    NASA Astrophysics Data System (ADS)

    Arunbabu, K. P.; Ahmad, S.; Chandra, A.; Dugad, S. R.; Gupta, S. K.; Hariharan, B.; Hayashi, Y.; Jagadeesan, P.; Jain, A.; Jhansi, V. B.; Kawakami, S.; Kojima, H.; Mohanty, P. K.; Morris, S. D.; Nayak, P. K.; Oshima, A.; Rao, B. S.; Reddy, L. V.; Shibata, S.; Tanaka, K.; Zuberi, M.

    2017-09-01

    The large area (560 m2) GRAPES-3 tracking muon telescope has been operating uninterruptedly at Ooty, India since 2001. Every day, it records 4 × 109 muons of ≥1 GeV with an angular resolution of ∼4°. The variation of atmospheric temperature affects the rate of decay of muons produced by the galactic cosmic rays (GCRs), which in turn modulates the muon intensity. By analyzing the GRAPES-3 data of six years (2005-2010), a small (amplitude ∼0.2%) seasonal variation (1 year (Yr) period) in the intensity of muons could be measured. The effective temperature 'Teff' of the upper atmosphere also displays a periodic variation with an amplitude of ∼1 K which was responsible for the observed seasonal variation in the muon intensity. At GeV energies, the muons detected by the GRAPES-3 are expected to be anti-correlated with Teff. The anti-correlation between the seasonal variation of Teff, and the muon intensity was used to measure the temperature coefficient αT by fast Fourier transform (FFT) technique. The magnitude of αT was found to scale with the assumed attenuation length 'λ' of the hadrons in the range λ = 80-180 g cm-2. However, the magnitude of the correction in the muon intensity was found to be almost independent of the value of λ used. For λ = 120 g cm-2 the value of temperature coefficient αT was found to be (- 0.17 ± 0.02)% K-1.

  17. High energy gamma-ray observations of the Crab Nebula and pulsar with the Solar Tower Atmospheric Cherenkov Effect Experiment

    NASA Astrophysics Data System (ADS)

    Oser, Scott Michael

    The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a new ground-based atmospheric Cherenkov telescope for gamma-ray astronomy. STACEE uses the large mirror area of a solar heliostat facility to achieve a low energy threshold. A prototype experiment which uses 32 heliostat mirrors with a total mirror area of ~1200 m2 has been constructed. This prototype, called STACEE-32, was used to search for high energy gamma-ray emission from the Crab Nebula and Pulsar. Observations taken between November 1998 and February 1999 yield a strong statistical excess of gamma- like events from the Crab, with a significance of +6.75σ in 43 hours of on-source observing time. No evidence for pulsed emission from the Crab Pulsar was found, and the upper limit on the pulsed fraction of the observed excess was < 5.5% at the 90% confidence level. A subset of the data was used to determine the integral flux of gamma rays from the Crab. We report an energy threshold of Eth = 190 +/- 60 GeV, and a measured integral flux of I(E > Eth) = (2.2 +/- 0.6 +/- 0.2) × 10-10 photons cm-2 s-1. The observed flux is in agreement with a continuation to lower energies of the power law spectrum seen at TeV energies.

  18. Structure of the Venus neutral atmosphere as observed by the Radio Science experiment VeRa on Venus Express

    NASA Astrophysics Data System (ADS)

    Tellmann, Silvia; Pätzold, Martin; Häusler, Bernd; Bird, Michael K.; Tyler, G. Leonard

    2009-04-01

    The European Space Agency Venus Express Radio Science experiment (VeRa) obtained 118 radio occultation measurements of the Venusian atmosphere between July 2006 and June 2007. Southern latitudes are uniformly sampled; measurements in the northern hemisphere are concentrated near the pole. Radial profiles of neutral number density derived from the occultations cover the altitude range 40-90 km, which are converted to profiles of temperature (T) and pressure (p) versus height (h). Profiles of static stability are found to be latitude-dependent and nearly adiabatic in the middle cloud region. Below the clouds the stability decreases at high latitudes. At an altitude of 65 km, the VeRa T[p(h)] profiles generally lie between the Venus International Reference Atmosphere (VIRA) and VIRA-2 models; the retrieved temperatures at any given pressure level typically are within 5 K of those derived from the Pioneer Venus Orbiter Radio Occultation experiments. A large equator-to-pole temperature contrast of ˜30 K is found at the 1-bar (1000 hPa) level. The VeRa observations reveal a distinct cold collar region in the southern hemisphere, complementing that in the north. At the latitudes of the cold collars, the tropopause altitude increases relative to higher and lower latitudes by ≈7 km while the temperature drops roughly 60 K. The observations indicate the existence of a wave number 2 structure poleward of ±75° latitude at altitudes of 62 km.

  19. Assumption Centred Modelling of Ecosystem Responses to CO2 at Six US Atmospheric CO2 Enrichment Experiments.

    NASA Astrophysics Data System (ADS)

    Walker, A. P.; De Kauwe, M. G.; Medlyn, B. E.; Zaehle, S.; Luus, K. A.; Ryan, E.; Xia, J.; Norby, R. J.

    2015-12-01

    Plant photosynthetic rates increase and stomatal apertures decrease in response to elevated atmospheric CO[2] (eCO2), increasing both plant carbon (C) availability and water use efficiency. These physiological responses to eCO2 are well characterised and understood, however the ecological effects of these responses as they cascade through a suite of plant and ecosystem processes are complex and subject to multiple interactions and feedbacks. Therefore the response of the terrestrial carbon sink to increasing atmospheric CO[2] remains the largest uncertainty in global C cycle modelling to date, and is a huge contributor to uncertainty in climate change projections. Phase 2 of the FACE Model-Data Synthesis (FACE-MDS) project synthesises ecosystem observations from five long-term Free-Air CO[2] Enrichment (FACE) experiments and one open top chamber (OTC) experiment to evaluate the assumptions of a suite of terrestrial ecosystem models. The experiments are: The evergreen needleleaf Duke Forest FACE (NC), the deciduous broadleaf Oak Ridge FACE (TN), the prairie heating and FACE (WY), and the Nevada desert FACE, and the evergreen scrub oak OTC (FL). An assumption centered approach is being used to analyse: the interaction between eCO2 and water limitation on plant productivity; the interaction between eCO2 and temperature on plant productivity; whether increased rates of soil decomposition observed in many eCO2 experiments can account for model deficiencies in N uptake shown during Phase 1 of the FACE-MDS; and tracing carbon through the ecosystem to identify the exact cause of changes in ecosystem C storage.

  20. Scaling water and energy fluxes in climate systems - Three land-atmospheric modeling experiments

    NASA Technical Reports Server (NTRS)

    Wood, Eric F.; Lakshmi, Venkataraman

    1993-01-01

    Three numerical experiments that investigate the scaling of land-surface processes - either of the inputs or parameters - are reported, and the aggregated processes are compared to the spatially variable case. The first is the aggregation of the hydrologic response in a catchment due to rainfall during a storm event and due to evaporative demands during interstorm periods. The second is the spatial and temporal aggregation of latent heat fluxes, as calculated from SiB. The third is the aggregation of remotely sensed land vegetation and latent and sensible heat fluxes using TM data from the FIFE experiment of 1987 in Kansas. In all three experiments it was found that the surface fluxes and land characteristics can be scaled, and that macroscale models based on effective parameters are sufficient to account for the small-scale heterogeneities investigated.

  1. Perdigão 2015: methodology for atmospheric multi-Doppler lidar experiments

    NASA Astrophysics Data System (ADS)

    Vasiljević, Nikola; Palma, José M. L. M.; Angelou, Nikolas; Matos, José Carlos; Menke, Robert; Lea, Guillaume; Mann, Jakob; Courtney, Michael; Frölen Ribeiro, Luis; Gomes, Vitor M. M. G. C.

    2017-09-01

    The long-range and short-range WindScanner systems (LRWS and SRWS), multi-Doppler lidar instruments, when combined together can map the turbulent flow around a wind turbine and at the same time measure mean flow conditions over an entire region such as a wind farm. As the WindScanner technology is novel, performing field campaigns with the WindScanner systems requires a methodology that will maximize the benefits of conducting WindScanner-based experiments. Such a methodology, made up of 10 steps, is presented and discussed through its application in a pilot experiment that took place in a complex and forested site in Portugal, where for the first time the two WindScanner systems operated simultaneously. Overall, this resulted in a detailed site selection criteria, a well-thought-out experiment layout, novel flow mapping methods and high-quality flow observations, all of which are presented in this paper.

  2. AMPS data management concepts. [Atmospheric, Magnetospheric and Plasma in Space experiment

    NASA Technical Reports Server (NTRS)

    Metzelaar, P. N.

    1975-01-01

    Five typical AMPS experiments were formulated to allow simulation studies to verify data management concepts. Design studies were conducted to analyze these experiments in terms of the applicable procedures, data processing and displaying functions. Design concepts for AMPS data management system are presented which permit both automatic repetitive measurement sequences and experimenter-controlled step-by-step procedures. Extensive use is made of a cathode ray tube display, the experimenters' alphanumeric keyboard, and the computer. The types of computer software required by the system and the possible choices of control and display procedures available to the experimenter are described for several examples. An electromagnetic wave transmission experiment illustrates the methods used to analyze data processing requirements.

  3. Scaling water and energy fluxes in climate systems - Three land-atmospheric modeling experiments

    NASA Technical Reports Server (NTRS)

    Wood, Eric F.; Lakshmi, Venkataraman

    1993-01-01

    Three numerical experiments that investigate the scaling of land-surface processes - either of the inputs or parameters - are reported, and the aggregated processes are compared to the spatially variable case. The first is the aggregation of the hydrologic response in a catchment due to rainfall during a storm event and due to evaporative demands during interstorm periods. The second is the spatial and temporal aggregation of latent heat fluxes, as calculated from SiB. The third is the aggregation of remotely sensed land vegetation and latent and sensible heat fluxes using TM data from the FIFE experiment of 1987 in Kansas. In all three experiments it was found that the surface fluxes and land characteristics can be scaled, and that macroscale models based on effective parameters are sufficient to account for the small-scale heterogeneities investigated.

  4. Sandia National Laboratories ASCOT (atmospheric studies in complex terrain) field experiment, September 1980

    NASA Astrophysics Data System (ADS)

    Woods, R. O.

    1982-04-01

    During the period September 8 through September 25, 1980, Sandia National Laboratories, Division 4774, participated in a series of experiments held in the Geysers area of California. These experiments, aimed at providing data on nighttime drainage flow in complex terrain, were intended to provide a reliable basis for mathematical fow modeling. Tracers were released at several points on a valley rim and sampled by a large number of stations at ground level. Sandia's contribution was to make it possible to derive vertical tracer profiles. This was done by taking air samples from a captive balloon at chosen altitudes between the surface and 450 meters above ground.

  5. Shortwave feedbacks and El Nino-Southern Oscillation: Forced ocean coupled ocean-atmosphere experiments

    NASA Technical Reports Server (NTRS)

    Waliser, Duane E.; Blanke, Bruno; Neelin, J. David; Gautier, C.

    1994-01-01

    Changes in tropical sea surface temperature (SST) can produce changes in cloudiness that modify incoming solar shortwave (SW) radiation, which in turn affects SST. The effects of this negative feedback on Pacific interannual variability are examined in forced ocean model and hybrid coupled ocean-atmosphere model simulations. Two empirical schemes are used to model the large-scale, low-frequency response of surface SW to SST anomalies. The first scheme attempts to account for the nonlocal nature of the atmospheric response to SST based patterns of covariability analyzed through singular value decomposition. In the observations the primary coupled mode of variability is composed of a SW anomaly in the central Pacific that covaries with anomalous SST in the eastern Pacific. This is applied in the model as a nonlocal feedback. The second scheme examines the effects of a purely local feedback with a spatially varying coefficient of magnitude chosen similar to the first scheme. In almost all cases the second scheme behaved similarly to the first, presumably because the correlation scale of SST is large enough for El Nino-Southern Oscillation (ENSO) dynamics that there is little sensitivity to the local approximation in the SW feedback. In simulations forced by time series of observed wind stress the SW feedback induced very minor SST damping. Results for a simpified heat budget analysis showed that while the SW feedback increased the local heat flux damping on SST, it also induced a mean shallowing of the mixed layer. The resulting changes in both the local mean vertical temperature gradient and the zonal velocity response to the wind stress acted to oppose the local heat flux damping effects. When the observed SW anomalies were applied to forced simulations, the simulated SST anomalies were modified as expected, and agreement with observed SST improved. In coupled simulations the SW feedbacks had greater impact than in the case of specified stress. The main effects were

  6. Shipboard Turbulence Measurements of the Marine Atmospheric Boundary Layer from Hires Experiment

    DTIC Science & Technology

    2012-07-01

    Bodega Bay (Fig. 1). In- situ and sodar turbulence measurements were collected onboard R/V Robert Gordon Sproul (about 35 m length and 9.5 m...Turbulence data were collected during the HiRes main experiment aboard R/V Sproul in June, 2010 offshore of Bodega Bay, California. Although two sets

  7. Feasibility of perfluorocarbon tracers (PFTs) in atmospheric source-receptor experiments

    SciTech Connect

    Dietz, R.N.; Senum, G.I.

    1984-03-01

    A brief description of the perfluorocarbon tracer (PFT) system, which includes the tracers and the release equipment, the air samplers and the analyzers, is presented along with details on the research needs to provide a viable system for MATEX-scenario experiments. The present family of 2 viable PFTs needs to be increased to 5 to 6. Given the present precision of the analysis system, a one year long tracer experiment consisting of 4 hour releases every 60 hours from 5 different sites would require nearly 150 metric tons of PFTs at a cost of $15,000,000. Shortcomings in the programmable sampler include the pump, the sampling sequence control flexibility, data storage and retrieval, and the lack of remote communication capability; sampler adsorbent studies are also needed. The analytical system, including the catalyst processing bed, the chromatography column resolution, and the linearity of the detector, is in need of significant improvement. A higher resolution analysis system could significantly reduce analysis time but, more importantly, reduce tracer requirements more than 10-fold, for a cost savings potential of more than $13,000,000. A model is presented to demonstrate the feasibility of tracer material balances. Assessment of earlier long-range tracer experiments indicates the need for possibly 400 ground sampling sites requiring $8 to $14 million worth of samplers for a one-year tracer experiment. As many as six aircraft would be needed to conduct airborne model validation and material balance studies for each tracer plume.

  8. Science objectives and performance of a radiometer and window design for atmospheric entry experiments

    NASA Technical Reports Server (NTRS)

    Craig, Roger A.; Davy, William C.; Whiting, Ellis E.

    1994-01-01

    This paper describes the techniques developed for measuring stagnation-point radiation in NASA's cancelled Aeroassist Flight Experiment (AFE). It specifies the need for such a measurement; the types and requirements for the needed instruments; the Radiative Heating Experiment (RHE) developed for the AFE; the requirements, design parameters, and performance of the window developed for the RHE; the procedures and summary of the technique; and results of the arc-jet wind tunnel experiment conducted to demonstrate the overall concept. Subjects emphasized are the commercial implications of the knowledge to be gained by this experiment in connection with the Aeroassisted Space Transfer Vehicle (ASTV), the nonequilibrium nature of the radiation, concerns over the contribution of vacuum-ultraviolet radiation to the overall radiation, and the limit on the flight environment of the vehicle imposed by the limitations on the window material. Results show that a technique exists with which the stagnation-point radiation can be measured in flight in an environment of interest to commercial ASTV applications.

  9. Atmospheric peroxides over the North Pacific during IOC 2002 shipboard experiment.

    PubMed

    Kim, Young-Mi; Lee, Meehye; Chang, Wonil; Lee, Gangwoong; Kim, Kyung-Ryul; Kato, Shungo

    2007-11-01

    Atmospheric hydrogen peroxide and methyl hydroperoxide were determined onboard the Melville over the North Pacific from Osaka to Honolulu during May-June 2002. The concentrations of H(2)O(2) and CH(3)OOH increased from 0.64+/-0.57 ppbv and 0.27+/-0.59 ppbv in subpolar region (30-50 degrees N) to 1.96+/-0.95 ppbv and 1.56+/-1.3 ppbv in subtropical region (24-30 degrees N). The increase in concentrations towards the Equator was more pronounced for CH(3)OOH than H(2)O(2). In contrast, the levels of O(3) and CO were decreased at lower latitudes as air mass was more aged, denoted by the ratios of C(2)H(2)/CO and C(3)H(8)/C(2)H(6). CH(3)OOH concentrations showed a clear diurnal variation with a maximum around noon and minimum before sunrise. Frequently, the concentrations of peroxides remained over 1 ppbv in the dark and even gradually increased after sunset. In addition, the ratios of C(2)H(4)/C(2)H(6) and C(3)H(6)/C(3)H(8) were increased in aged subtropical air, which implies that these alkenes were emitted from the ocean surface. As a result, the reaction of these biogenic alkenes with O(3) was suggested to be a potential source for peroxides in aged marine air at lower latitudes.

  10. An overview of organically bound tritium experiments in plants following a short atmospheric HTO exposure.

    PubMed

    Galeriu, D; Melintescu, A; Strack, S; Atarashi-Andoh, M; Kim, S B

    2013-04-01

    The need for a less conservative, but reliable risk assessment of accidental tritium releases is emphasized in the present debate on the nuclear energy future. The development of a standard conceptual model for accidental tritium releases must be based on the process level analysis and the appropriate experimental database. Tritium transfer from atmosphere to plants and the subsequent conversion into organically bound tritium (OBT) strongly depends on the plant characteristics, seasons, and meteorological conditions, which have a large variability. The present study presents an overview of the relevant experimental data for the short term exposure, including the unpublished information, also. Plenty of experimental data is provided for wheat, rice, and soybean and some for potato, bean, cherry tomato, radish, cabbage, and tangerine as well. Tritiated water (HTO) uptake by plants during the daytime and nighttime has an important role in further OBT synthesis. OBT formation in crops depends on the development stage, length, and condition of exposure. OBT translocation to the edible plant parts differs between the crops analyzed. OBT formation during the nighttime is comparable with that during the daytime. The present study is a preliminary step for the development of a robust model of crop contamination after an HTO accidental release.

  11. CLINICAL EXPERIENCE AND IMPACT OF A COMMUNITY-LED VOLUNTEER ATMOSPHERIC HAZE CLINIC IN SINGAPORE.

    PubMed

    Yeo, Benson; Liew, Choon Fong; Oon, Hazel H

    2014-11-01

    The Pollutant Standards Index reached a life-threatening level of 401 in Singapore on 21 June 2013. Grassroot leaders in Ulu Pandan Constituency conducted the first community-led free atmospheric Haze Clinic from 25 June 2013 to 11 July 2013 to provide accessible medical assessment for affected community members. This provided insight into the common conditions afflicting that community during the haze period while allaying public anxiety. Seventy-two consultations were conducted over the 3 week period, of which 26 (36.1%) were haze related, 18 (25%) were possibly haze related and 28 (38.9%) were non-haze related. The majority of haze-related complaints were respiratory, eye and skin-related. During a haze crisis, such adhoc community-led clinics may help alleviate the surge in patients seen at emergency departments and public primary health clinics. Many of the patients seen were from low income families and a significant number (38.9%) sought help for non-haze related medical conditions.

  12. Exobiological implications of dust aggregation in planetary atmospheres: An experiment for the gas-grain simulation facility

    NASA Technical Reports Server (NTRS)

    Huntington, J. L.; Schwartz, D. E.; Marshall, J. R.

    1991-01-01

    The Gas-Grain Simulation Facility (GGSF) will provide a microgravity environment where undesirable environmental effects are reduced, and thus, experiments involving interactions between small particles and grains can be more suitably performed. Slated for flight aboard the Shuttle in 1992, the ESA glovebox will serve as a scientific and technological testbed for GGSF exobiology experiments as well as generating some basic scientific data. Initial glovebox experiments will test a method of generating a stable, mono-dispersed cloud of fine particles using a vibrating sprinkler system. In the absence of gravity and atmospheric turbulence, it will be possible to determine the influence of interparticle forces in controlling the rate and mode of aggregation. The experimental chamber can be purged of suspended matter to enable multiple repetitions of the experiments. Of particular interest will be the number of particles per unit volume of the chamber, because it is suspected that aggregation will occur extremely rapidly if the number exceeds a critical value. All aggregation events will be recorded on high-resolution video film. Changes in the experimental procedure as a result of surprise events will be accompanied by real-time interaction with the mission specialist during the Shuttle flight.

  13. Science objectives and performance of a radiometer and window design for atmospheric entry experiments

    NASA Technical Reports Server (NTRS)

    Craig, Roger A.; Davy, William C.; Whiting, Ellis E.

    1994-01-01

    The Radiative Heating Experiment, RHE, aboard the Aeroassist Flight Experiment, AFE, (now cancelled) was to make in-situ measurements of the stagnation region shock layer radiation during an aerobraking maneuver from geosynchronous to low earth orbit. The measurements were to provide a data base to help develop and validate aerothermodynamic computational models. Although cancelled, much work was done to develop the science requirements and to successfully meet RHE technical challenges. This paper discusses the RHE scientific objectives and expected science performance of a small sapphire window for the RHE radiometers. The spectral range required was from 170 to 900 nm. The window size was based on radiometer sensitivity requirements including capability of on-orbit solar calibration.

  14. Transient desorption of water vapor - A potential source of error in upper atmosphere rocket experiments

    NASA Technical Reports Server (NTRS)

    Kendall, B. R. F.; Weeks, J. O.

    1974-01-01

    Results of measurements of the outgassing rates of samples of materials and surface finishes used on the outer skins of rocket-borne experiment packages in simulated rocket ascents. The results showed outgassing rates for anodized aluminum in the second minute of flight which are two to three orders of magnitude higher than those given in typical tables of outgassing rates. The measured rates for aluminum with chromate conversion surface coatings were also abnormally high. These abnormally high initial rates fell quickly after about five to ten minutes to values comparable with those in the published literature. It is concluded that anodized and chromate conversion coatings on the aluminum outer surfaces of a sounding rocket experiment package will cause gross distortion of the true water vapor environment.

  15. Mass storage system experiences and future needs at the National Center for Atmospheric Research

    NASA Technical Reports Server (NTRS)

    Olear, Bernard T.

    1992-01-01

    This presentation is designed to relate some of the experiences of the Scientific Computing Division at NCAR dealing with the 'data problem'. A brief history and a development of some basic Mass Storage System (MSS) principles are given. An attempt is made to show how these principles apply to the integration of various components into NCAR's MSS. There is discussion of future MSS needs for future computing environments.

  16. Dynamic Analysis of the Low Power Atmospheric Compensation Experiment (LACE) Spacecraft

    DTIC Science & Technology

    1990-06-01

    QUANTITATIVE TESTS FOR CHAOS The previous section summarized qualitative methods that require experience to evaluate chaotic systems. There are some 79...C 1.53 .0454 D 13.8 .0454 The initial analysis consists of studying four qualitative indicators of chaos. They are time history, fourier power... qualitative indicators for cases A and B respectively. The time history is initially transient and then becomes periodic in both cases. The fourier

  17. Meteorites : a la recherche de leurs corps parents

    NASA Astrophysics Data System (ADS)

    Jaquet, Emmanuel

    2017-07-01

    Meteorites arrive on Earth with no indication of their cosmic provenance, yet they are essentially our only tangible witnesses of the extra-atmospheric universe. We sketch the two-century history of the search for meteorite parent bodies and present the current status of meteorites-asteroids and meteorites-planetary bodies links.

  18. An experiment to determine atmospheric CO concentrations of tropical South Atlantic air samples

    NASA Astrophysics Data System (ADS)

    Kirchhoff, V. W. J. H.; Aires, C. B.; Alvala, P. C.

    2003-04-01

    New observations of atmospheric carbon monoxide, CO, are described, from tropical South Atlantic air samples. A new observational site, Maxaranguape, was set up in a clean remote environment right next to the ocean on the north-east coast of Brazil, to obtain CO mixing ratios and auxiliary data (meteorological parameters, ozone (O3), carbon dioxide (CO2) and methane (CH4)) during three sequential seasonal cycles. The seasonal variations of temperature, humidity and precipitation are shown for the new site. Chromatographic separation followed by mercury oxide detection is used to measure CO. The seasonality of the CO data was clearly established. Minima are seen during April, May and June showing wet-period averages of 56.1 parts per billion by volume (ppbv), with standard deviation 8.7 ppbv; during dry-period months, August to November, the average was 77.7 ± 16.5 ppbv. For comparison, CO concentrations were also measured over continental areas in Brazil. Much larger values have been found in moderate 'burning' regions, such as the south of the state of Mato Grosso and the north-western part of the state of Parana, where 200 ppbv in the dry season has been observed. Since normally the air masses have travelled for several days over the ocean, the air masses over the site present low chemical activity. Daily variations of CO2 are very small, of the order of a few percent relative to the diurnal mean. Only on rare occasions, when the wind direction changes, is the sampled air contaminated from flowing over the inhabited shoreline to the south, and then CO2 varies inversely with O3. The monthly mean CH4 data does not show a clear seasonal variation, possibly because the amplitude of the CH4 variation is only of the order of 1%, which is close to the precision of the measuring instrument.

  19. Airborne spectral measurements of surface-atmosphere anisotropy during the SCAR-A, Kuwait oil fire, and TARFOX experiments

    NASA Astrophysics Data System (ADS)

    Soulen, Peter F.; King, Michael D.; Tsay, Si-Chee; Arnold, G. Thomas; Li, Jason Y.

    2000-04-01

    During the SCAR-A, Kuwait Oil Fire Smoke Experiment, and TARFOX deployments, angular distributions of spectral reflectance for various surfaces were measured using the scanning Cloud Absorption Radiometer (CAR) mounted on the nose of the University of Washington C-131A research aircraft. The CAR contains 13 narrowband spectral channels between 0.47 and 2.3 μm with a 190° scan aperture (5° before zenith to 5° past nadir) and 1° instantaneous field of view. The bidirectional reflectance is obtained by flying a clockwise circular orbit above the surface, resulting in a ground track approximately 3 km in diameter within about 2 min. Spectral bidirectional reflectances of four surfaces are presented: the Great Dismal Swamp in Virginia with overlying haze layer, the Saudi Arabian Desert and the Persian Gulf in the Middle East, and the Atlantic Ocean measured east of Richmond, Virginia. Although the CAR measurements are contaminated by atmospheric effects, results show distinct spectral characteristics for various types of surface-atmosphere systems, including hot spots, limb brightening and darkening, and Sun glint. In addition, the hemispherical albedo of each surface-atmosphere system is calculated directly by integrating over all high angular-resolution CAR measurements for each spectral channel. Comparing the nadir reflectance with the overall hemispherical albedo of each surface, we find that using nadir reflectances as a surrogate for hemispherical albedo can cause albedos to be underestimated by as much as 95% and overestimated by up to 160%, depending on the type of surface and solar zenith angle.

  20. Spatial and temporal distributions of ice nucleating particles during the Atmospheric Radiation Measurement (ARM) Cloud Aerosol Precipitation Experiment (ACAPEX)

    NASA Astrophysics Data System (ADS)

    Levin, E. J.; DeMott, P. J.; Suski, K. J.; Boose, Y.; Hill, T. C. J.; McCluskey, C. S.; Schill, G. P.; Duncan, D.; Al-Mashat, H.; Prather, K. A.; Sedlacek, A. J., III; Tomlinson, J. M.; Mei, F.; Hubbe, J. M.; Pekour, M. S.; Leung, L. R.; Kreidenweis, S. M.

    2016-12-01

    California is currently under drought conditions and changes in precipitation due to future climate change scenarios are uncertain. Thus, understanding the controlling factors for precipitation in this region, and having the capability to accurately model these scenarios, is important. A crucial area in understanding precipitation is in the interplay between atmospheric moisture and aerosols. Specifically, ice nucleation in clouds is an important process controlling precipitation formation. A major component of CA's yearly precipitation comes from wintertime atmospheric river (AR) events which were the focus of the 2015 Atmospheric Radiation Measurement (ARM) Cloud Aerosol Precipitation Experiment (ACAPEX) and CalWater 2 campaigns. These two campaigns provided sampling platforms on four aircraft, including the ARM Aerial Facility G-1, as well as the NOAA Ron Brown research vessel and at a ground station at Bodega Bay, CA. Measurements of ice nucleating particles (INPs) were made with the Colorado State University (CSU) Continuous Flow Diffusion Chamber (CFDC) aboard the G-1 and at Bodega Bay, and using aerosol filter collections on these platforms as well as the Ron Brown for post-processing via immersion freezing in the CSU Ice Spectrometer. Aerosol composition was measured aboard the G-1 with the Aerosol Time-of-Flight Mass Spectrometer (ATOFMS). Both the CFDC and ATOFMS sampled off of an isokinetic inlet when flying in clear air and a counter-flow virtual impactor in clouds to capture ice crystal and cloud droplet residuals. In this presentation we present ice nucleating particle concentrations before, during and after an AR event from air, ground and ocean-based measurements. We also examine INP concentration variability in orographic clouds and in clear air at altitude along the Sierra Nevada range, in the marine boundary layer and through the Central Valley, and relate these INP measurements to other aerosol physical and chemical properties.

  1. Simulating thin cirrus clouds in Observing System Simulation Experiments (OSSE) for LAWS. [Lidar Atmospheric Wind Sounder

    NASA Technical Reports Server (NTRS)

    Emmitt, G. D.; Wood, S. A.

    1991-01-01

    It was previously shown (Wood and Emmitt, 1990, 1991) that, by omitting the contribution of thin cirrus by the Observing System Simulation Experiments, will result in severe misrepresentation of both the frequency and the accuracy of wind observations in the upper troposphere. This paper estimates the presence of optically thin (tau less than 1.0) cirrus clouds by using model soundings in a cirrus cloud model. An example is presented showing the location of cirrus cloud profiles over North America for November 10, 1979, which were generated by the LAWS Simulation Model.

  2. Spectral Signature of Column Solar Radiation Absorption During the Atmospheric Radiation Measurement Enhanced Shortwave Experiment (ARESE). Revision

    SciTech Connect

    O'Hirok, William; Gautier, Catherine; Ricchiazzi, Paul

    1999-11-01

    Spectral and broadband shortwave radiative flux data obtained from the Atmospheric Radiation Measurement Enhanced Shortwave Experiment (ARESE) are compared with 3-D radiative transfer computations for the cloud field of October 30, 1995. Because the absorption of broadband solar radiation in the cloudy atmosphere deduced from observations and modeled differ by 135 Wm{sup -2}, we performed a consistency analysis using spectral observations and the model to integrate for wavelengths between the spectral observations. To match spectral measurements, aerosols need a reduction in both single scattering albedo (from 0.938 to 0.82) and asymmetry factor (from 0.67 to 0.61), and cloud droplets require a three-fold increase in co-albedo. Even after modifying the model inputs and microphysics the difference in total broadband absorption is still of the order of 75Wm{sup -2}. Finally, an unexplained absorber centered around 1.06 {micro}m appears in the comparison that is much too large to be explained by dimers.

  3. A natural experiment on plant acclimation: lifetime stomatal frequency response of an individual tree to annual atmospheric CO2 increase.

    PubMed

    Wagner, F; Below, R; Klerk, P D; Dilcher, D L; Joosten, H; Kürschner, W M; Visscher, H

    1996-10-15

    Carbon dioxide (CO2) has been increasing in atmospheric concentration since the Industrial Revolution. A decreasing number of stomata on leaves of land plants still provides the only morphological evidence that this man-made increase has already affected the biosphere. The current rate of CO2 responsiveness in individual long-lived species cannot be accurately determined from field studies or by controlled-environment experiments. However, the required long-term data sets can be obtained from continuous records of buried leaves from living trees in wetland ecosystems. Fine-resolution analysis of the lifetime leaf record of an individual birch (Betula pendula) indicates a gradual reduction of stomatal frequency as a phenotypic acclimation to CO2 increase. During the past four decades, CO2 increments of 1 part per million by volume resulted in a stomatal density decline of approximately 0.6%. It may be hypothesized that this plastic stomatal frequency response of deciduous tree species has evolved in conjunction with the overall Cenozoic reduction of atmospheric CO2 concentrations.

  4. Atmospheric Chemistry Experiment (ACE) Lower Stratospheric Trend Measurements: Approach and Preliminary Results based on Comparisons with ATMOS Midlatitude Observations

    NASA Astrophysics Data System (ADS)

    Rinsland, C. P.; Bernath, P. F.; McLeod, S.; Boone, C.; McHugh, M.; Walker, K.

    2003-12-01

    The Atmospheric Chemistry Experiment (ACE) was successfully launched on August 12, 2003, into a 73.9 degree inclined orbit at an altitude of 650 km onboard a U.S.-supplied Pegasus XL vehicle. The primary goal of the ACE mission is to measure solar occultation spectra from the UV to mid-infrared for a minimum of two years to determine whether or not the stratospheric ozone layer will begin to recover now that chlorofluorocarbon emissions have been banned. Among the instruments carried by the small Canadian-built satellite is a compact Fourier transform spectrometer designed to measure in the 750-4100 cm-1 region at 0.02 cm-1 spectral resolution. The measurements will provide an opportunity to determine lower stratospheric trends at midlatitudes by comparison of ACE measurements with measurements recorded by the Atmospheric Trace MOlecule Spectroscopy (ATMOS) Fourier transform spectometer at 0.01-cm-1 resolution during its first shuttle flight in 1985. We describe the approach to be used for trend determination, the status of the investigation, and the other data relevant for comparisons.

  5. Upper&lower Atmosphere Level and Stratospheric Utilities by Groundbased Observations with Helium Balloon Experiments Via Launching Systems

    NASA Astrophysics Data System (ADS)

    Kucuk, Furkan Ali

    2016-07-01

    We have initiated a low budget project, named "ULUGHBEG", that allows some high altitude experiments at stratosphere level. The main target is launching payloads weigh less than 2,5 kg to stratosphere. We used temperature and humidity insulated boxes made of Styrofoam (thickness:50 mm). Aerogel units which will be installed on the surfaces of boxes will be used for collecting micrometeorites which were spreaded out into stratosphere, after certain meteor showers.Air & light pollution sensors and IR cameras which are installed in our systems can easily detect air and light pollution. Thus, it will be possible to construct air and light pollution database in Turkey from stratosphere level. In this study, all devices and instruments necessary for this project are GPS modules, air & light pollution quality meters, pressure sensors, IR cameras, HD cameras and other specific sensors (i.e. temperature, humidity, radiation etc.). All tests (i.e. vacuum, temperature (ECSS-E-10-03A, ECSS-E-10-04A standarts)) were performed at Istanbul Technical University's Space Systems Test and Design Laboratory. As a summary, this project will help to develop researches related to space and atmospheric sciences in Turkey. Keywords: High Altitude Balloon, Atmospheric Effects, Astroparticle Physics

  6. The New Horizons Radio Science Experiment: Performance and Measurements of Pluto's Atmospheric Structure, Surface Pressure, and Surface Temperature

    NASA Astrophysics Data System (ADS)

    Linscott, I.; Hinson, D. P.; Bird, M. K.; Stern, A.; Weaver, H. A., Jr.; Olkin, C.; Young, L. A.; Ennico Smith, K.

    2015-12-01

    The New Horizons (NH) spacecraft payload contained the Radio Science Experiment (REX) for determining key characteristics of Pluto and Charon during the July 14, 2015, flyby of the Pluto/Charon system. The REX flight equipment augments the NH X-band radio transceiver by providing a high precision, narrow band recording of high power uplink transmissions from Earth stations, as well as a record of broadband radiometric power. This presentation will review the performance and initial results of two high- priority observations. First, REX received two pair of 20-kW signals, one pair per polarization, transmitted from the DSN at 4.2-cm wavelength during a diametric radio occultation by Pluto. REX recorded these uplink signals and determined precise measurement of the surface pressure, the temperature structure of the lower atmosphere, and the surface radius of Pluto. The ingress portion of one polarization was played back from the spacecraft in July and processed to obtain the pressure and temperature structure of Pluto's atmosphere. Second, REX measured the thermal emission from Pluto at 4.2- cm wavelength during two linear scans across the disk at close range when both the dayside and the night side are visible. Both scans extend from limb to limb with a resolution of one-tenth Pluto's disk and temperature resolution of 0.1 K. Occultation and radiometric temperature results presented here will encompass additional data scheduled for playback in September.

  7. Surface Temperature Probability Distributions and Extremes in the NARCCAP Hindcast Experiment: Evaluation Methodology and Metrics, Results, and Associated Atmospheric Mechanisms

    NASA Astrophysics Data System (ADS)

    Loikith, P.; Waliser, D. E.; Kim, J.; Lee, H.; Lintner, B. R.; Neelin, J.; McGinnis, S. A.; Mattmann, C. A.; Mearns, L. O.

    2013-12-01

    Daily surface temperature probability distribution functions (PDFs) for a suite of regional climate model (RCM) hindcast experiments participating in the North American Regional Climate Change Assessment Program (NARCCAP) are evaluated against two state-of-the-art high resolution reanalysis products over North America. While all models exhibit some level of temperature bias throughout the PDF, the majority of models capture higher moment statistics like variance and skewness with reasonable fidelity in the winter. More substantial disagreement exists in the simulation of the tails of the summer temperature distributions, with notable observational uncertainty, indicative of difficulty in properly simulating temperature extremes here. To better understand the mechanisms behind model-reanalysis disagreement, potential mechanisms affecting PDF shape are evaluated, focusing on events in the tails of the distribution. Composite analysis is employed to investigate differences in atmospheric circulation patterns associated with extreme temperature days at select locations where station data are available to reconcile reanalysis PDF uncertainty. In general, the models simulate large-scale atmospheric circulation patterns well where the shape of the PDF most resembles reanalysis, especially in the winter. Summertime patterns tend to be smaller in scale and lower in magnitude where extreme temperature occurrence may also be associated with local processes such as unusual soil moisture content and convective precipitation and cloudiness, introducing additional possibilities for model disagreement. From this comprehensive multi-model evaluation, it is possible to identify which models may be best suited to simulate temperature extremes under global warming conditions.

  8. Simulation of atmospheric circulation during the GIMEX 91 experiment using a meso-{gamma} primitive equations model

    SciTech Connect

    Gallee, H.; Fontaine de Ghelin, O.; Broeke, M.R. Van Den

    1995-11-01

    A meso-{gamma}-scale atmospheric model has been used to simulate atmospheric circulations observed during the Greenland Ice Margin EXperiment (GIMEX). The simulations shown here are two-dimensional and cover the 12-13 July 1991 period, a typical summer situation in this area. The synoptic-scale wind forcing is included. The tundra topography is assumed to be either flat, or averaged over a 50-km-wide cross section centered on the GIMEX transect. Simulated wind, temperature, humidity, and turbulent fluxes compare reasonably well with available observations. The simulated heat used to melt snow or ice is also shown. The sensitivity of the model results to the synoptic-scale wind forcing is significant. The impact of a tundra much warmer than the ocean on the ice sheet melting is discussed. It is found that weak easterly synoptic-scale winds are able to overwhelm this impact, especially when the tundra is assumed to be flat. 29 refs., 14 figs., 3 tabs.

  9. Land-atmosphere interactions in a changing climate: An overview of the GLACE-CMIP5 experiment

    NASA Astrophysics Data System (ADS)

    Seneviratne, S. I.; Wilhelm, M.; Stanelle, T.; Hurk, B. V. D.; Hagemann, S.; Berg, A. M.; Cheruy, F.; Higgins, M.; Lorenz, R.; Meier, A.; Brovkin, V.; Claussen, M.; Ducharne, A.; Dufresne, J. L.; Findell, K. L.; Ghattas, J.; Lawrence, D. M.; Malyshev, S.; Pitman, A. J.; Rummukainen, M.; Smith, B.

    2014-12-01

    The Global Land-Atmosphere Climate Experiment-Coupled Model Intercomparison Project phase 5 (GLACE-CMIP5) is a multimodel experiment investigating the impact of soil moisture-climate feedbacks in CMIP5 simulations (Seneviratne et al. 2013). This experiment builds upon previous studies investigating the role of soil moisture-atmosphere interactions for seasonal forecasting (Koster et al. 2004) and for regional climate projections (Seneviratne et al. 2006). A total of 6 modeling groups took part in the experiment (CESM, EC-EARTH, GFDL, IPSL, MPI-ESM, and more recently ACCESS). The results reveal that projected soil moisture changes by the end of the 21st century substantially impact climate in several regions on both hemispheres, both under present and future climate conditions. Strong and consistent effects are found on temperature, especially for extremes (about 1- 1.5K for mean temperature and 2- 2.5K for extreme daytime temperature). In the Northern Hemisphere, effects on mean and heavy precipitation are also found in most models, but the results are less consistent than for temperature. A direct scaling between soil moisture induced changes in evaporative cooling and resulting changes in temperature mean and extremes is found in the simulations. Further results from more recent analyses, especially regarding impacts on extremes will be discussed. The presentation will also address the implications of these results for climate extremes attribution and climate change adaptation, as well as follow-up activities under CMIP6. References: Koster, R.D., et al., 2004: Science, 305, 1138-1140. Koster, R.D., et al., 2010: Geophys. Res. Lett., 37, L02402, doi:10.1029/2009GL041677. Seneviratne, S.I., D. Lüthi, M. Litschi, and C. Schär, 2006: Nature, 443, 205-209.Seneviratne, S.I., M. Wilhelm, T. Stanelle, B.J.J.M. van den Hurk, S. Hagemann, A. Berg, F. Cheruy, M.E. Higgins, A. Meier, V. Brovkin, M. Claussen, A. Ducharne, J.-L. Dufresne, K.L. Findell, J. Ghattas, D

  10. Une formation à la recherche en médecine transfusionnelle dans le monde francophone

    PubMed Central

    Shiboski, C.; Fontanet, A.; Murphy, E.L.

    2010-01-01

    Un enseignement accéléré et francophone de formation à la recherche en médecine transfusionnelle a été récemment instauré à l’Institut Pasteur de Paris, sous la codirection de membres hospitalo-universitaires de l’université de Californie San Francisco (UCSF), du Blood Systems Research Institute (BSRI) et de l’Institut national de la transfusion sanguine (INTS). Le but est de former des professionnels de la transfusion des pays en voie de développement à mener une activité de recherche dont les résultats peuvent contribuer à un renforcement de la qualité des soins transfusionnels et de la sécurité transfusionnelle dans leur pays. Le cours enseigne les méthodes de recherche clinique et épidémiologique, et leurs applications transfusionnelles potentielles. Chaque étudiant élabore au cours du stage un protocole personnel de recherche, qu’il lui sera loisible de mettre ensuite en pratique dans le centre de transfusion ou l’hôpital où il exerce. PMID:19640755

  11. Education Relative a l'Environnement: Regards, Recherches, Reflexions. Volume 3.

    ERIC Educational Resources Information Center

    2002

    This volume presents the work of a colloquium on the theme "Education a l'environnement: Mouveaux publics, mouveax partenaires" that took place May 3-4, 2000 in Poitiers. Papers include: (1) "Pourquoi rechercher de nouvezus publics pour l'education relative a l'environnement?" (Louis Goffin); (2) "Le partenariat en education relative a…

  12. Education Relative a l'Environnement: Regards, Recherches, Reflexions. Volume 3.

    ERIC Educational Resources Information Center

    2002

    This volume presents the work of a colloquium on the theme "Education a l'environnement: Mouveaux publics, mouveax partenaires" that took place May 3-4, 2000 in Poitiers. Papers include: (1) "Pourquoi rechercher de nouvezus publics pour l'education relative a l'environnement?" (Louis Goffin); (2) "Le partenariat en education relative a…

  13. EAQUATE: An International Experiment for Hyper-Spectral Atmospheric Sounding Validation

    NASA Technical Reports Server (NTRS)

    Taylor, J. P.; Smith, W.; Cuomo, V.; Larar, A.; Zhou, D.; Serio, C.; Maestri, T.; Rizzi, R.; Newman, S.; Antonelli, P.; Mango, S.; DiGirolamo, P.; Esposito, F.; Grieco, G.; Summa, D.; Restieri, R.; Masiello, G.; Romano, F.; Pappalardo, G.; Pavese, G.; Mona, L.; Amodeo, A.; Pisani, G.

    2008-01-01

    The international experiment called EAQUATE (European AQUA Thermodynamic Experiment) was held in September 2004 in Italy and the United Kingdom to demonstrate certain ground-based and airborne systems useful for validating hyperspectral satellite sounding observations. A range of flights over land and marine surfaces were conducted to coincide with overpasses of the AIRS instrument on the EOS Aqua platform. Direct radiance evaluation of AIRS using NAST-I and SHIS has shown excellent agreement. Comparisons of level 2 retrievals of temperature and water vapor from AIRS and NAST-I validated against high quality lidar and drop sonde data show that the 1K/1km and 10%/1km requirements for temperature and water vapor (respectively) are generally being met. The EAQUATE campaign has proven the need for synergistic measurements from a range of observing systems for satellite cal/val and has paved the way for future cal/val activities in support of IASI on the European Metop platform and CrIS on the US NPP/NPOESS platform.

  14. An analysis of the AVE-SESAME I period using statistical structure and correlation functions. [Atmospheric Variability Experiment-Severe Environmental Storm and Mesoscale Experiment

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.; Meyer, P. J.

    1984-01-01

    Structure and correlation functions are used to describe atmospheric variability during the 10-11 April day of AVE-SESAME 1979 that coincided with the Red River Valley tornado outbreak. The special mesoscale rawinsonde data are employed in calculations involving temperature, geopotential height, horizontal wind speed and mixing ratio. Functional analyses are performed in both the lower and upper troposphere for the composite 24 h experiment period and at individual 3 h observation times. Results show that mesoscale features are prominent during the composite period. Fields of mixing ratio and horizontal wind speed exhibit the greatest amounts of small-scale variance, whereas temperature and geopotential height contain the least. Results for the nine individual times show that small-scale variance is greatest during the convective outbreak. The functions also are used to estimate random errors in the rawinsonde data. Finally, sensitivity analyses are presented to quantify confidence limits of the structure functions.

  15. An analysis of the AVE-SESAME I period using statistical structure and correlation functions. [Atmospheric Variability Experiment-Severe Environmental Storm and Mesoscale Experiment

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.; Meyer, P. J.

    1984-01-01

    Structure and correlation functions are used to describe atmospheric variability during the 10-11 April day of AVE-SESAME 1979 that coincided with the Red River Valley tornado outbreak. The special mesoscale rawinsonde data are employed in calculations involving temperature, geopotential height, horizontal wind speed and mixing ratio. Functional analyses are performed in both the lower and upper troposphere for the composite 24 h experiment period and at individual 3 h observation times. Results show that mesoscale features are prominent during the composite period. Fields of mixing ratio and horizontal wind speed exhibit the greatest amounts of small-scale variance, whereas temperature and geopotential height contain the least. Results for the nine individual times show that small-scale variance is greatest during the convective outbreak. The functions also are used to estimate random errors in the rawinsonde data. Finally, sensitivity analyses are presented to quantify confidence limits of the structure functions.

  16. Results of the US contribution to the joint US/USSR Bering Sea experiment. [atmospheric circulation and sea ice cover

    NASA Technical Reports Server (NTRS)

    Campbell, W. J.; Chang, T. C.; Fowler, M. G.; Gloersen, P.; Kuhn, P. M.; Ramseier, R. O.; Ross, D. B.; Stambach, G.; Webster, W. J., Jr.; Wilheit, T. T.

    1974-01-01

    The atmospheric circulation which occurred during the Bering Sea Experiment, 15 February to 10 March 1973, in and around the experiment area is analyzed and related to the macroscale morphology and dynamics of the sea ice cover. The ice cover was very complex in structure, being made up of five ice types, and underwent strong dynamic activity. Synoptic analyses show that an optimum variety of weather situations occurred during the experiment: an initial strong anticyclonic period (6 days), followed by a period of strong cyclonic activity (6 days), followed by weak anticyclonic activity (3 days), and finally a period of weak cyclonic activity (4 days). The data of the mesoscale test areas observed on the four sea ice option flights, and ship weather, and drift data give a detailed description of mesoscale ice dynamics which correlates well with the macroscale view: anticyclonic activity advects the ice southward with strong ice divergence and a regular lead and polynya pattern; cyclonic activity advects the ice northward with ice convergence, or slight divergence, and a random lead and polynya pattern.

  17. Lidar In-Space Technology Experiment (LITE) - NASA's first in-space lidar system for atmospheric research

    NASA Technical Reports Server (NTRS)

    Couch, Richard H.; Rowland, Carroll W.; Ellis, K. Scott; Blythe, Michael P.; Regan, Curtis P.; Koch, Michael R.; Antill, Charles W.; Kitchen, Wayne L.; Cox, John W.; Delorme, Joseph F.

    1991-01-01

    Engineering aspects are presented of the design, fabrication, integration, and operation of the Lidar In-Space Technology Experiment (LITE) for flight aboard the Space Shuttle in mid-1993. The LITE system is being developed by NASA/Langley Research Center and will be used to detect stratospheric and tropospheric aerosols, probe the planetary boundary layer, measure cloud top heights, and measure atmospheric temperature and density in the 10- to 40-km range. The system consists of a nominal telescope receiver 1 meter in diameter, a three-color Nd:YAG laser transmitter, and the system electronics. The system makes extensive use of Space Shuttle resources for electrical power, thermal control, and command and data handling.

  18. Lidar In-Space Technology Experiment (LITE) - NASA's first in-space lidar system for atmospheric research

    NASA Technical Reports Server (NTRS)

    Couch, Richard H.; Rowland, Carroll W.; Ellis, K. Scott; Blythe, Michael P.; Regan, Curtis P.; Koch, Michael R.; Antill, Charles W.; Kitchen, Wayne L.; Cox, John W.; Delorme, Joseph F.

    1991-01-01

    Engineering aspects are presented of the design, fabrication, integration, and operation of the Lidar In-Space Technology Experiment (LITE) for flight aboard the Space Shuttle in mid-1993. The LITE system is being developed by NASA/Langley Research Center and will be used to detect stratospheric and tropospheric aerosols, probe the planetary boundary layer, measure cloud top heights, and measure atmospheric temperature and density in the 10- to 40-km range. The system consists of a nominal telescope receiver 1 meter in diameter, a three-color Nd:YAG laser transmitter, and the system electronics. The system makes extensive use of Space Shuttle resources for electrical power, thermal control, and command and data handling.

  19. Modeling HOx/O3 chemistry in the tropical marine boundary during the Pacific Atmospheric Sulfur Experiment

    NASA Astrophysics Data System (ADS)

    Gu, D.; Gray, B. A.; Wang, Y.; Mauldin, L.; Cantrell, C.; Heikes, B. G.; Higbie, A.; O'Sullivan, D. W.; Campos, T.; Pollack, I. B.; Heizer, C. G.; Weinheimer, A. J.

    2008-12-01

    C-130 observations of OH, RO2, O3, CO, H2O2, and CH3OOH in the tropical marine boundary layer during the 2007 Pacific Atmospheric Sulfur Experiment are analyzed using a one- dimensional chemistry transport model. Meteorological parameters are simulated from the Weather Research and Forecasting model. The coupling of low-NOx photochemistry and mixing processes is examined over the relatively homogeneous region. Simulated vertical profiles of HOx radicals and peroxides are not always in agreement with the measurements. Potential factors contributing to the discrepancies are investigated. The large ozone decrease towards the surface is driven in part by large photochemical loss in the marine boundary layer. The vertical gradient is also regulated by the influx of ozone from free troposphere and diffusion transport in the boundary layer. This experimental constraint on model simulated vertical transport is evaluated.

  20. Workplan for Catalyzing Collaboration with Amazonian Universities in the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)

    NASA Technical Reports Server (NTRS)

    Brown, I. Foster; Moreira, Adriana

    1997-01-01

    Success of the Large-Scale Biosphere-Atmospheric Experiment in Amazonia (LBA) program depends on several critical factors, the most important being the effective participation of Amazonian researchers and institutions. Without host-county counterparts, particularly in Amazonia, many important studies cannot he undertaken due either to lack of qualified persons or to legal constraints. No less important, the acceptance of the LBA program in Amazonia is also dependent on what LBA can do for improving the scientific expertise in Amazonia. Gaining the active investment of Amazonian scientists in a comprehensive research program is not a trivial task. Potential collaborators are few, particularly where much of the research was to be originally focused - the southern arc of Brazilian Amazonia. The mid-term goals of the LBA Committee on Training and Education are to increase the number of collaborators and to demonstrate that LBA will be of benefit to the region.

  1. Global atmospheric response to specific linear combinations of the main SST modes.. Part I: numerical experiments and preliminary results

    NASA Astrophysics Data System (ADS)

    Trzaska, S.; Moron, V.; Fontaine, B.

    1996-10-01

    This article investigates through numerical experiments the controversial question of the impact of El Niño-Southern Oscillation (ENSO) phenomena on climate according to large-scale and regional-scale interhemispheric thermal contrast. Eight experiments (two considering only inversed Atlantic thermal anomalies and six combining ENSO warm phase with large-scale interhemispheric contrast and Atlantic anomaly patterns) were performed with the Météo-France atmospheric general circulation model. The definition of boundary conditions from observed composites and principal components is presented and preliminary results concerning the month of August, especially over West Africa and the equatorial Atlantic are discussed. Results are coherent with observations and show that interhemispheric and regional scale sea-surface-temperature anomaly (SST) patterns could significantly modulate the impact of ENSO phenomena: the impact of warm-phase ENSO, relative to the atmospheric model intercomparison project (AMIP) climatology, seems stronger when embedded in global and regional SSTA patterns representative of the post-1970 conditions [i.e. with temperatures warmer (colder) than the long-term mean in the southern hemisphere (northern hemisphere)]. Atlantic SSTAs may also play a significant role. Acknowledgements. We gratefully appreciate the on-line DMSP database facility at APL (Newell et al., 1991) from which this study has benefited greatly. We wish to thank E. Friis-Christensen for his encouragement and useful discussions. A. Y. would like to thank the Danish Meteorological Institute, where this work was done, for its hospitality during his stay there and the Nordic Baltic Scholarship Scheme for its financial support of this stay. Topical Editor K.-H. Glassmeier thanks M. J. Engebretson and H. Lühr for their help in evaluating this paper.--> Correspondence to: A. Yahnin-->

  2. The atmospheric composition geostationary satellite constellation for air quality and climate science: Evaluating performance with Observation System Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Edwards, D. P.; Barre, J.; Worden, H. M.; Arellano, A. F.; Gaubert, B.; Anderson, J. L.; Mizzi, A. P.; Lahoz, W. A.

    2014-12-01

    Current satellite observations of tropospheric composition made from low Earth orbit provide at best one or two measurements each day at any given location. Coverage is global but sparse, often with large uncertainties in individual measurements that limit examination of local and regional atmospheric composition over short time periods. This has hindered the operational uptake of these data for monitoring air quality and population exposure, and for initializing and evaluating chemical weather forecasts. By the end of the current decade there are planned geostationary Earth orbit (GEO) satellite missions for atmospheric composition over North America, East Asia and Europe with additional missions proposed. Together, these present the possibility of a constellation of GEO platforms to achieve continuous time-resolved high-density observations of continental domains for mapping pollutant sources and variability on diurnal and local scales. We describe Observing System Simulation Experiments (OSSEs) to evaluate the contributions of these GEO missions to improve knowledge of near-surface air pollution due to intercontinental long-range transport and quantify chemical precursor emissions. We discuss the requirements on measurement simulation, chemical transport modeling, and data assimilation for a successful OSSE infrastructure. Our approach uses an efficient computational method to sample a high-resolution global GEOS-5 chemistry Nature Run over each geographical region of the GEO constellation. The demonstration carbon monoxide (CO) observation simulator, which is being expanded to other chemical pollutants, currently produces multispectral retrievals and captures realistic scene-dependent variation in measurement vertical sensitivity and cloud cover. We use the DART Ensemble Adjustment Kalman Filter to assimilate the simulated observations in a CAM-Chem global chemistry-climate model Control Run. The impact of observing over each region is evaluated using data

  3. The resolution dependency of atmospheric blocking in the aqua-planet experiments

    NASA Astrophysics Data System (ADS)

    Jiang, T.

    2015-12-01

    Quasi-stationary planetary waves forced by topography or other zonally asymmetric features are usually suggested to be essential for blocking formation; however, we found the 2-D feature of blocking could also occur frequently without these precondition. In a set of aqua-planet simulations with setting of perpetual spring, the blocking feature is identified through a combination of meridional height gradient and 2-D height anomaly. The general distribution resembles the Pacific blocking, but more equatorward. The resolution sensitivity experiment suggests that, associated with the poleward shift of the subtropical jet stream, the blocking activity also moves northward with higher resolution, and converges between 60km and 30km. The blocking with finer resolution also shows a more realistic characteristic timesale. By utilizing the wave activity budget analysis, it is found that, in the decay stage, the effective diffusivity would be much larger, thus the blocking waves are absorbed more efficiently by the mean flow.

  4. Large-scale vertical motion calculations in the AVE IV Experiment. [of atmospheric wind velocity

    NASA Technical Reports Server (NTRS)

    Wilson, G. S.

    1976-01-01

    Using 3- and 6-h consecutive rawinsonde and surface data from NASA's AVE IV Experiment, synoptic-scale vertical motion calculations are made using an adiabatic technique and three variations of the kinematic technique. Both subjective and objective comparisons in space and time between the sign and magnitude of the computed vertical velocities and precipitation intensities are made. These comparisons are conducted to determine which method would consistently produce realistic magnitudes, patterns, and vertical profiles of vertical velocity essential to the diagnostic study of the relationship between severe convective storms and their environment in AVE IV. The kinematic method, adjusted to the adiabatic value at 100 mb, proved to produce the best overall vertical velocities.

  5. Exploratory laser experiments. [measurement of atmospheric water vapor via optical radar

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Experiments are described which were undertaken to explore the application of various dye laser methods for generating laser pulses which could be tuned over H2O absorption lines in the visible and near infrared. Specific topics discussed include: operation of a long pulse dye laser with a tunable, narrow band output at high energies near the 5915 A water vapor absorption bands; assembly and operation of a short duration dye laser near the 5915 A water vapor absorption bands; construction of a dye laser to be pumped to operate in the red and near infrared; and preliminary studies of the beam divergence of the output of the a laser-pumped system. Results are summarized.

  6. Monthly mean simulation experiments with a course-mesh global atmospheric model

    NASA Technical Reports Server (NTRS)

    Spar, J.; Klugman, R.; Lutz, R. J.; Notario, J. J.

    1978-01-01

    Substitution of observed monthly mean sea-surface temperatures (SSTs) as lower boundary conditions, in place of climatological SSTs, failed to improve the model simulations. While the impact of SST anomalies on the model output is greater at sea level than at upper levels the impact on the monthly mean simulations is not beneficial at any level. Shifts of one and two days in initialization time produced small, but non-trivial, changes in the model-generated monthly mean synoptic fields. No improvements in the mean simulations resulted from the use of either time-averaged initial data or re-initialization with time-averaged early model output. The noise level of the model, as determined from a multiple initial state perturbation experiment, was found to be generally low, but with a noisier response to initial state errors in high latitudes than the tropics.

  7. Le partenariat en recherche: un véhicule pour atteindre les plus hauts sommets.

    PubMed

    Gélinas, Isabelle

    2016-10-01

    Les partenariats en ergothérapie entre les praticiens et les chercheurs sont importants pour produire des connaissances pertinentes pour la pratique clinique et pour favoriser la pratique fondée sur les données probantes au sein de la profession. BUT: Dans ce discours Muriel Driver, l'auteure discute des raisons pour lesquelles nous devons favoriser la participation des praticiens à la recherche et elle examine les conditions essentielles à la réussite des partenariats de recherche en collaboration. QUESTIONS CLÉS: Les partenariats de collaboration peuvent réduire les obstacles empêchant les praticiens de participer à la recherche et permettre de veiller à ce que les initiatives de recherche soient plus pertinentes pour la pratique clinique. Les facteurs clés pour établir et maintenir des partenariats significatifs sont la présence de conditions préalables et favorables au partenariat en lien avec le contexte, de même que l'utilisation de principes directeurs axés sur la vision, les valeurs, la confiance, la communication, le partage du pouvoir et les interactions. CONSÉQUENCES: Plusieurs des facteurs identifiés comme étant favorables à la réussite d'un partenariat de collaboration correspondent aux rôles fondamentaux des ergothérapeutes et témoignent de nos valeurs professionnelles. La prise en compte de ces facteurs lors de l'établissement de collaborations de recherche permettrait d'accroître les probabilités de réussite. © CAOT 2016.

  8. Continuing Studies of Planetary Atmospheres Associated with Experiments on the Galileo Jupiter Probe and Infrared Observations of Venus

    NASA Technical Reports Server (NTRS)

    Ragent, Boris

    1998-01-01

    The results of the nephelometer experiment conducted aboard the Probe of the Galileo mission to Jupiter are presented. The tenuous clouds and sparse particulate matter in the relatively particle-free 5-micron "hot spot" region of the Probe's descent were documented from about 0.46 bars to about 12 bars. Three regions of apparent coherent structure were noted, in addition to many indications of extremely small particle concentrations along the descent path. From the first valid measurement at about 0.46 bars down to about 0.55 bars a feeble decaying lower portion of a cloud, corresponding with the predicted ammonia particle cloud, was encountered. A denser, but still very modest, particle structure was present in the pressure regime extending from about 0.76 to a distinctive base at 1.34 bars, and is compatible with the expected ammonium hydrosulfide cloud. No massive water cloud was encountered, although below the second structure, a small, vertically thin layer at about 1.65 bars may be detached from the cloud above, but may also be water condensation, compatible with reported measurements of water abundance from other Galileo Mission experiments. A third small signal region, extending from about 1.9 to 4.5 bars, exhibited quite weak but still distinctive structure, and, although the identification of the light scatterers in this region is uncertain, may also be a water cloud perhaps associated with lateral atmospheric motion and/or reduced to a small mass density by atmospheric subsidence or other explanations. Rough descriptions of the particle size distributions and cloud properties in these regions have been derived, although they may be imprecise because of the small signals and experimental difficulties. These descriptions document the small number densities of particles, the moderate particle sizes, generally in the slightly submicron to few micron range, and the resulting small optical depths, mass densities due to particles, column particle number loading

  9. Continuing Studies of Planetary Atmospheres Associated With Experiments on the Galileo Jupiter Probe and Infrared Observations of Venus

    NASA Technical Reports Server (NTRS)

    Goodman,Jindra; Ragent, Boris

    1998-01-01

    The results of the nephelometer experiment conducted aboard the Probe of the Galileo mission to Jupiter are presented. The tenuous clouds and sparse particulate matter in the relatively particle-free 5-micron "hot spot" region of the Probe's descent were documented from about 0.46 bars to about 12 bars. Three regions of apparent coherent structure were noted, in addition to many indications of extremely small particle concentrations along the descent path. From the first valid measurement at about 0.46 bars down to about 0.55 bars a feeble decaying lower portion of a cloud, corresponding with the predicted ammonia particle cloud, was encountered. A denser, but still very modest, particle structure was present in the pressure regime extending from about 0.76 to a distinctive base at 1.34 bars, and is compatible with the expected ammonium hydrosulfide cloud. No massive water cloud was encountered, although below the second structure, a small, vertically thin layer at about 1.65 bars may be detached from the cloud above, but may also be water condensation, compatible with reported measurements of water abundance from other Galileo Mission experiments. A third small signal region, extending from about 1.9 to 4.5 bars, exhibited quite weak but still distinctive structure, and, although the identification of the light scatterers in this region is uncertain, may also be a water cloud perhaps associated with lateral atmospheric motion and/or reduced to a small mass density by atmospheric subsidence or other explanations. Rough descriptions of the particle size distributions and cloud properties in these regions have been derived, although they may be imprecise because of the small signals and experimental difficulties. These descriptions document the small number densities of particles, the moderate particle sizes, generally in the slightly submicron to few micron range, and the resulting small optical depths, mass densities due to particles, column particle number loading

  10. Measurements of CH4, N2O, CO, H2O, and O3 in the middle atmosphere by the Atmospheric Trace Molecule Spectroscopy Experiment on Spacelab 3

    NASA Technical Reports Server (NTRS)

    Gunson, M. R.; Farmer, C. B.; Norton, R. H.; Zander, R.; Rinsland, C. P.

    1990-01-01

    The volume mixing ratios of five minor gases (CH4, N2O, CO, H2O, and O3) have been retrieved through the middle atmosphere from the analysis of 0.01/cm resolution infrared solar occultation spectra recorded near 28 deg N and 48 deg S latitudes with the Atmospheric Trace Molecule Spectroscopy instrument, flow on board Spacelab 3 (April 30 through May 6, 1985). The results are in general agreement with reported measurements from ground-, balloon-, and satellite-based instruments for the same seasons. In detail, the vertical profiles of these gases show the effects of the upper and middle atmospheric transport patterns dominant during the season of these observations. The profiles inferred at different longitudes around 28 deg N suggest a near-uniform zonal distribution of these gases, for conditions corresponding to late spring. The sunrise occultation measurements point to a larger longitudinal variability in the vertical distribution of these gases at 48 deg S.

  11. Measurements of the UV Nocturnal Atmospheric Background in the 300-400 nm Wavelength Band with the Experiment BaBy during a Transmediterranean Balloon Flight

    NASA Astrophysics Data System (ADS)

    Giarrusso, S.; Gugliotta, G.; Agnetta, G.; Assis, P.; Biondo, B.; Catalano, O.; Celi, F.; Cusumano, G.; D'Ali Staiti, G.; Raffaele, R.Di.; Espirito-Santo, M.C.; Gabriele, M.; Rosa, G.La; Maccarone, M.C.; Mangano, A.; Mineo, T.; Pimenta, M.; Russo, F.; Sacco, B.; Santangelo, A.; Scarsi, P.; Tome, B.

    2003-07-01

    We present new results of U V no cturnal atmospheric background measured with the balloon borne experiment BaBy that performed a trans-Mediterranean flight on July 11 2002. The experiment looked downwards from about 40 km of altitude the dark no cturnal atmosphere over the sea in a moonless night. It is composed of 8 filtered and collimated fast PMTs detecting the U V light in the 300-400 nm wavelength band and in the 3 narrow bands centered at the emission lines of the atmospheric Nitrogen molecules. Both single photon counting and charge integration methods are used in pairs of PMTs with the same filter. The background measured over the sea is about 300 photons m-2 sr-1 ns-1 in the 300-400 nm wavelength band. Introduction The Backround Bypass, BaBy, experiment is a scientific support activity to the evaluation of the sensitivity of EUSO [3], devoted to the observation of the Extreme Energy Cosmic Rays from space by detecting U V fluorescence light. One of the fundamental information in EUSO design is the U V no cturnal atmospheric background level whose main sources are: light pollution from cities, planes and ships, naturally occurring bioluminescence, lightning flashes, reflected moonlight and starlight, auroral flashes, low energy cosmic ray air showers and atmospheric chemical reactions. Since 1998, no cturnal atmospheric U V background measurements, in the wavelength interval (300-400 nm) relevant for EUSO, have been performed by

  12. The Wind and Temperature Spectrometer (WTS) in the Atmospheric Neutral Density Experiment (ANDE) Satellite

    NASA Technical Reports Server (NTRS)

    Herrero, F. A.; Vancil, B.; Nicholas, A.; Zaruba, C.; Beasley, L.

    2004-01-01

    Miniaturization efforts in new spectrometers for ionosphere/thermosphere investigations of the ion-drifts and neutral winds and corresponding temperatures make possible very light (about 250 g) packages consuming less than 0.4 W. Previously described, our approach measures the angular and energy distributions of neutral atoms and molecules (or ions) in two perpendicular planes; using those distributions to determine the full wind vector, the temperature and the relative densities of O and N2, as required for the ANDE mission. The measurements require two separate electron impact ion sources each with its own electron beam cathode. We have developed a low-temperature thermionic emission cathode that delivers 1 mA electron current at 80 mW power, making it possible to operate neutral wind-temperature experiments for the first time with powers less than 0.5 W. Advances in the ion optics of the energy-angle spectrometer enhance the energy resolution-aperture product more than a factor of 3 to enable energy resolutions of a few percent with large apertures. With these technology improvements it is now possible to obtain the full neutral wind vector, temperature and O/N2, density ratio once per second in a 250g/0.4W package with sensitivity up to about 500 km altitude in the thermosphere. We will describe the WTS as deployed in ANDE and show simulated data with the non-linear least squares analysis to illustrate expected performance of the WTS in the estimated errors in the three components of the wind, the temperature, and the relative densities.

  13. The Charged Aerosol Release Experiment (Care II) to Study Artificial Dusty Plasmas in the Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.; Siefring, C. L.; Gatling, G.; Briczinski, S. J., Jr.; Vierinen, J.; Bhatt, A.; Holzworth, R. H., II; McCarthy, M.; Gustavsson, B.; La Hoz, C.; Latteck, R.

    2015-12-01

    A sounding rocket launched from Andoya, Norway in September 2015 carried 37 rocket motors and a multi-instrument daughter payload into the ionosphere to study the generation of plasma wave electric fields and ionospheric density disturbances by the high-speed injection of dust particles. The primary purpose of the CARE II mission is to validate the dress-particle theory of enhanced incoherent scatter from a dusty plasma and to validate models of plasma instabilities driven by high-speed charged particles. The CARE II chemical payload produces 66 kg of micron-sized dust particles composed of aluminium oxide. In addition to the dust, simple molecular combustion products such as N2, H2, CO2, CO, H20 and NO will be injected into the bottomside of the F-layer. Charging of the dust and ion charge exchange with the molecules yields plasma particles moving at hypersonic velocities. Streaming instabilities and shear electric fields causes plasma turbulence that can be detected using ground radars and in situ plasma instruments. The instrument payload was separated from the chemical release payload soon after launch to measure electric field vectors, electron and ion densities, and integrated electron densities from the rocket to the ground. The chemical release of high speed dust was directed upward on the downleg of the rocket trajectory to intersect the F-Layer. The instrument section was about 600 meters from the dust injection module at the release time. Ground HF and UHF radars were operated to detected scatter and refraction by the modified ionosphere. Optical instruments from airborne and ground observatories were used to map the dispersal of the dust using scattered sunlight. The plasma interactions are being simulated with both fluid and particle-in-cell (PIC) codes. CARE II is a follow-on to the CARE I rocket experiment conducted from Wallops Island Virginia in September 2009.

  14. Data for NASA's AVE 3 experiment: 25-mb sounding data and synoptic charts. [investigation of atmospheric parameters detected from satellite data under conditions of heavy snow cover

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.; Turner, R. E.

    1975-01-01

    The atmospheric variability experiment (AVE 3) is described and tabulated rawinsonde data at 25-mb intervals from the surface to 25 mb for the 41 stations is presented. The experiment was conducted between February 6 and February 7, 1975. Brief discussions are given on methods of data processing, changes in the reduction scheme since the AVE 2 pilot experiment, and data accuracy. An example of contact data is presented as well as synoptic charts prepared from the data.

  15. ["Recherche de la vraye anathomie des dents, nature et propriété d'icelles", the first French dentistry book by the surgeon from Rouergue, Urbain Hémard (Benoist Rigaud, Lyon, 1582].

    PubMed

    Ruel-Kellermann, Micheline

    2010-01-01

    Recherche sur la vraye anathomie des dents, nature & propriété d'icelles (1582) is the last dental book of the 16th century and the first in France. The part borrowed from Libellus de dentibus by Bartolommeo Eustachio is not the most interesting part of the book; the better part is when Hémard tells personal experiences with his picturesque words, showing violent situations of care at this epoch.

  16. Nocturnal atmospheric uv background measurements in the 300-400 nm band with baby 2001: a balloon borne experiment to flight on board of a transmediterranean balloon.

    NASA Astrophysics Data System (ADS)

    Giarrusso, S.; Agnetta, G.; Biondo, B.; Catalano, O.; Cusumano, G.; Gugliotta, G.; La Rosa, G.; Maccarone, M.C.; Mangano, A.; Russo, F.; Sacco, B.

    In the framework of the EUSO project (an experiment approved by ESA to be accommodate on board of the ISS) we present a new balloon borne experimental apparatus, named BABY 2001 that is devoted to systematic and exhaustive observations of the UV nocturnal atmospheric background. The BABY 2001 experiment is foreseen to flight on the 3rd 4th week of July 2001 from the Milo-Trapani base on board of a transmediterranean balloon, looking downward from about 40 km of altitude the dark nocturnal atmosphere over the sea. The apparatus used for the BABY 2001 experiment was designed and built at the IFCAI-CNR in Palermo. The instrument is composed by 8 filtered and collimated fast photomultipliers, two of them detecting the UV light in the 300-400 nm wavelengths band and the others in the three narrow bands centered at the emission lines of the atmospheric Nitrogen molecules.

  17. Demonstration of Technologies for Remote and in Situ Sensing of Atmospheric Methane Abundances - a Controlled Release Experiment

    NASA Astrophysics Data System (ADS)

    Aubrey, A. D.; Thorpe, A. K.; Christensen, L. E.; Dinardo, S.; Frankenberg, C.; Rahn, T. A.; Dubey, M.

    2013-12-01

    It is critical to constrain both natural and anthropogenic sources of methane to better predict the impact on global climate change. Critical technologies for this assessment include those that can detect methane point and concentrated diffuse sources over large spatial scales. Airborne spectrometers can potentially fill this gap for large scale remote sensing of methane while in situ sensors, both ground-based and mounted on aerial platforms, can monitor and quantify at small to medium spatial scales. The Jet Propulsion Laboratory (JPL) and collaborators recently conducted a field test located near Casper, WY, at the Rocky Mountain Oilfield Test Center (RMOTC). These tests were focused on demonstrating the performance of remote and in situ sensors for quantification of point-sourced methane. A series of three controlled release points were setup at RMOTC and over the course of six experiment days, the point source flux rates were varied from 50 LPM to 2400 LPM (liters per minute). During these releases, in situ sensors measured real-time methane concentration from field towers (downwind from the release point) and using a small Unmanned Aerial System (sUAS) to characterize spatiotemporal variability of the plume structure. Concurrent with these methane point source controlled releases, airborne sensor overflights were conducted using three aircraft. The NASA Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) participated with a payload consisting of a Fourier Transform Spectrometer (FTS) and an in situ methane sensor. Two imaging spectrometers provided assessment of optical and thermal infrared detection of methane plumes. The AVIRIS-next generation (AVIRIS-ng) sensor has been demonstrated for detection of atmospheric methane in the short wave infrared region, specifically using the absorption features at ~2.3 μm. Detection of methane in the thermal infrared region was evaluated by flying the Hyperspectral Thermal Emission Spectrometer (Hy

  18. Student Award Finalist - Simulation of the reignition of atmospheric pressure air discharges behind dielectric obstacles: comparison with experiments

    NASA Astrophysics Data System (ADS)

    Pechereau, Francois; Bourdon, Anne

    2013-09-01

    In recent years, experimental studies on plasma assisted catalysis for flue gas treatment have shown a significant reduction of pollutants at a low energetic cost. Catalyst supports are either random or organized two phase media such as pellets, monoliths or porous media. Then, in plasma reactors, atmospheric pressure discharges have to interact with many obstacles and to propagate in microcavities and pores. To better understand the discharge dynamics in these complex structures, experiments have been carried out at LPGP (Orsay, France) in a point-to-plane geometry with a dielectric plane obstacle placed in the discharge path. In this work, we have carried out discharge simulations in the experimental geometry. We have compared the dynamics of the discharge ignited at the point and its impact on the dielectric surface. Then, we have compared the conditions of a discharge reignition behind the dielectric obstacle. A good qualitative agreement with experiments has been obtained but to improve the quantitative comparison, we have carried out a detailed parametric numerical study. In this work, we will focus on the influence of the level of seed charges on the discharge reignition and discuss several physical processes that could have an impact on the level of seed charges. ALVEOPLAS project (Grant No. ANR-08-BLAN-0159-01).

  19. Organic Composition of Size-Segregated Aerosols Sampled During the 2002 Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA

    NASA Astrophysics Data System (ADS)

    Tremblay, R. T.; Zika, R. G.

    2003-04-01

    Aerosol samples were collected for the analysis of organic source markers using non-rotating Micro Orifice Uniform Deposit Impactors (MOUDI) as part of the Bay Regional Atmospheric Chemistry Experiment (BRACE) in Tampa, FL, USA. Daily samples were collected 12 m above ground at a flow rate of 30 lpm throughout the month of May 2002. Aluminum foil discs were used to sample aerosol size fractions with aerodynamic cut diameter of 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.17 and 0.093 um. Samples were solvent extracted using a mixture of dichloromethane/acetone/hexane, concentrated and then analyzed using gas chromatography-mass spectrometry (GC/MS). Low detection limits were achieved using a HP Programmable Temperature Vaporizing inlet (PTV) and large volume injections (80ul). Excellent chromatographic resolution was obtained using a 60 m long RTX-5MS, 0.25 mm I.D. column. A quantification method was built for over 90 organic compounds chosen as source markers including straight/iso/anteiso alkanes and polycyclic aromatic hydrocarbons (PAH). The investigation of potential aerosol sources for different particle sizes using known organic markers and source profiles will be presented. Size distributions of carbon preference indices (CPI), percent wax n-alkanes (%WNA) and concentration of selected compounds will be discussed. Also, results will be compared with samples acquired in different environments including the 1999 Atlanta SuperSite Experiment, GA, USA.

  20. Atmospheric photochemistry of aromatic hydrocarbons: Analysis of OH budgets during SAPHIR chamber experiments and evaluation of MCMv3.2

    NASA Astrophysics Data System (ADS)

    Nehr, S.; Bohn, B.; Brauers, T.; Dorn, H.; Fuchs, H.; Häseler, R.; Hofzumahaus, A.; Li, X.; Lu, K.; Rohrer, F.; Tillmann, R.; Wahner, A.

    2012-12-01

    Aromatic hydrocarbons, almost exclusively originating from anthropogenic sources, comprise a significant fraction of volatile organic compounds observed in urban air. The photo-oxidation of aromatics results in the formation of secondary pollutants and impacts air quality in cities, industrialized areas, and districts of dense traffic. Up-to-date photochemical oxidation schemes of the Master Chemical Mechanism (MCMv3.2) exhibit moderate performance in simulating aromatic compound degradation observed during previous environmental chamber studies. To obtain a better understanding of aromatic photo-oxidation mechanisms, we performed experiments with a number of aromatic hydrocarbons in the outdoor atmosphere simulation chamber SAPHIR located in Jülich, Germany. These chamber studies were designed to derive OH turnover rates exclusively based on experimental data. Simultaneous measurements of NOx (= NO + NO2), HOx (= OH + HO2), and the total OH loss rate constant k(OH) facilitate a detailed analysis of the OH budgets during photo-oxidation experiments. The OH budget analysis was complemented by numerical model simulations using MCMv3.2. Despite MCM's tendency to overestimate k(OH) and to underpredict radical concentrations, the OH budgets are reasonably balanced for all investigated aromatics. However, the results leave some scope for OH producing pathways that are not considered in the current MCMv3.2. An improved reaction mechanism, derived from MCMv3.2 sensitivity studies, is presented. The model performance is basically improved by changes of the mechanistic representation of ring fragmentation channels.

  1. The Second Phase of the Global Land Atmosphere Coupling Experiment (GLACE-2): Impact of Land Initialization on Subseasonal Forecasts

    NASA Technical Reports Server (NTRS)

    Koster, Randal; Mahanama, Sarith

    2012-01-01

    The recently-completed second phase of the Global Land-Atmosphere Coupling Experiment (GLACE-2) focused on quantifying, for boreal summer, the subseasonal (out to two months) forecast skill for precipitation and air temperature that can be derived from the realistic initialization of land surface states, notably soil moisture. An overview of the multi-institutional numerical experiment is described, along with a determination and characterization of multi-model "consensus" skill. The models show modest but significant land-derived skill in predicting air temperatures out to two months, especially where the rain gauge network is dense. Given that precipitation is the chief driver of soil moisture, and thereby assuming that rain gauge density is a reasonable proxy for the adequacy of the observational network contributing to soil moisture initialization, this result indeed highlights the potential contribution of enhanced observations to prediction. Land-derived precipitation forecast skill is much weaker than that for air temperature. The skill for predicting air temperature, and to some extent precipitation, increases with the magnitude of the initial soil moisture anomaly. GLACE-2 results are examined further to provide insight into the asymmetric impacts of wet and dry soil moisture initialization on skill.

  2. Temperature and pressure retrievals from the Atmospheric Chemistry Experiment (ACE): a new technique and comparison with COSMIC

    NASA Astrophysics Data System (ADS)

    Olsen, Kevin; Strong, Kimberly; Toon, Geoff; Boone, Chris

    We present results of a new technique to retrieve temperature and pressure profiles from satellite remote sensing spectra collected by the Canadian Space Agency's (CSA) Atmospheric Chemistry Experiment (ACE), which recently celebrated its tenth year in orbit. ACE utilizes a high-resolution (0.02 cm (-1) ) Fourier Transform Spectrometer (FTS) operating between 750-4400 cm (-1) in limb-scanning mode using the sun as a light source (solar occultation). This technique benefits from high signal strength, high resolution, and self calibration. The CSA and NASA's Jet Propulsion Laboratory (JPL) developed a proposal to send a similar instrument to Mars: the Mars Atmospheric Trace Molecule Occultation Spectrometer (MATMOS, later canceled). To support this we have developed a new set of retrieval algorithms based on GGG used by the Total Carbon Column Observing Network (TCCON) and have applied these algorithms to ACE-FTS data. When performing temperature retrievals, the current approach of the ACE team is to fix the volume mixing ratio of CO_2 and carry out spectral fitting, varying temperature. While this method works very well and has been well validated, it relies on several assumptions, emph{a priori} knowledge, and data from models. Operating at another planet, these emph{a priori} are unknown and the models have not been developed to a suitable level. We demonstrate that by analyzing vibration-rotation bands of CO_2, we can retrieve vertical profiles of both temperature and pressure. Our retrieved temperature profiles are compared to those from ACE and the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), and are used to retrieve volume mixing ratio vertical profiles for several gases, such as methane. The effects that variability in temperature and pressure have on retrieved VMR profiles is shown and retrieved VMR profiles are compared with those from ACE.

  3. Forecasting skill assessment of an oil spill simulation system in the NE Aegean and atmospheric forcing perturbation experiments

    NASA Astrophysics Data System (ADS)

    Kailas, Marios; Chrysagi, Eyrydice; Sofianos, Sarantis

    2016-04-01

    In the present study, the predictive skill of an oil spill simulation system implemented in the Northern Aegean Sea was evaluated using field observations from surface drifters, provided in the framework of the TOSCA project. The system produces satisfactory results as in most cases the forecasting error is quite small, allowing the operational use of the forecast. In order to examine the sensitivity of the forecast to atmospheric forcing, additional simulations with perturbed atmospheric conditions were performed, using a time-shifting technique. In most experiments the differences between the simulations are relatively small, most likely due to slow oceanic response to variations in the wind fields. From the individual simulations an ensemble forecast was created, the results of which were also compared with the observations. The results suggest that by applying this method a safer forecast can be provided, especially regarding cases for which the wind-driven circulation is predominant. However, in cases where the circulation is characterized by intense velocity gradients (in the NE Aegean this is associated with the thermohaline front created by the Black Sea Water inflow), larger differences are present. They are related to imprecise representation of the location of the front. In these cases, the ensemble method produced no significant improvement since the relatively small differences between the trajectories of the ensemble members indicate that the position of the front in not significantly affected by the wind perturbations, based on the spatio-temporal scales examined. It is concluded that in regions with large spatio-temporal variability, an ensemble forecast produced by simulations generated from perturbed initial conditions could possibly lead to more robust results.

  4. Temperature profiling of the atmospheric boundary layer with rotational Raman lidar during the HD(CP)2 observational prototype experiment

    NASA Astrophysics Data System (ADS)

    Hammann, E.; Behrendt, A.; Le Mounier, F.; Wulfmeyer, V.

    2014-11-01

    The temperature measurements of the Rotational Raman Lidar of the University of Hohenheim (UHOH RRL) during the High Definition of Clouds and Precipitation for advancing Climate Prediction (HD(CP)2 Prototype Experiment (HOPE) in April and May 2013 are discussed. The lidar consists of a frequency-tripled Nd:YAG laser at 355 nm with 10 W average power at 50 Hz, a two-mirror scanner, a 40 cm receiving telescope and a highly efficient polychromator with cascading interference filters for separating four signals: the elastic backscatter signal, two rotational Raman signals with different temperature dependence, and the vibrational Raman signal of water vapor. The main measurement variable of the UHOH RRL is temperature. For the HOPE campaign, the lidar receiver was optimized for high and low background levels, respectively, with a novel switch for the passband of the second rotational Raman channel. The instrument delivers atmospheric profiles of water vapor mixing ratio as well as particle backscatter coefficient and particle extinction coefficient as further products. As examples for the measurement performance, measurements of the temperature gradient and water vapor mixing ratio revealing the development of the atmospheric boundary layer within 25 h are presented. As expected from simulations, a significant advance during nighttime was achieved with the new low-background setting. A two-mirror scanner allows for measurements in different directions. When pointing the scanner to low elevation, measurements close to the ground become possible which are otherwise impossible due to the non-total overlap of laser beam and receiving telescope field-of-view in the near range. We present an example of a low-level temperature measurement which resolves the temperature gradient at the top of the stable nighttime boundary layer a hundred meters above the ground.

  5. Temperature profiling of the atmospheric boundary layer with rotational Raman lidar during the HD(CP)2 Observational Prototype Experiment

    NASA Astrophysics Data System (ADS)

    Hammann, E.; Behrendt, A.; Le Mounier, F.; Wulfmeyer, V.

    2015-03-01

    The temperature measurements of the rotational Raman lidar of the University of Hohenheim (UHOH RRL) during the High Definition of Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observation Prototype Experiment (HOPE) in April and May 2013 are discussed. The lidar consists of a frequency-tripled Nd:YAG laser at 355 nm with 10 W average power at 50 Hz, a two-mirror scanner, a 40 cm receiving telescope, and a highly efficient polychromator with cascading interference filters for separating four signals: the elastic backscatter signal, two rotational Raman signals with different temperature dependence, and the vibrational Raman signal of water vapor. The main measurement variable of the UHOH RRL is temperature. For the HOPE campaign, the lidar receiver was optimized for high and low background levels, with a novel switch for the passband of the second rotational Raman channel. The instrument delivers atmospheric profiles of water vapor mixing ratio as well as particle backscatter coefficient and particle extinction coefficient as further products. As examples for the measurement performance, measurements of the temperature gradient and water vapor mixing ratio revealing the development of the atmospheric boundary layer within 25 h are presented. As expected from simulations, a reduction of the measurement uncertainty of 70% during nighttime was achieved with the new low-background setting. A two-mirror scanner allows for measurements in different directions. When pointing the scanner to low elevation, measurements close to the ground become possible which are otherwise impossible due to the non-total overlap of laser beam and receiving telescope field of view in the near range. An example of a low-level temperature measurement is presented which resolves the temperature gradient at the top of the stable nighttime boundary layer 100 m above the ground.

  6. Pan-Eurasian experiment (PEEX) establishing a process towards high level Pan-Eurasian atmosphere-ecosystem observation networks

    NASA Astrophysics Data System (ADS)

    Lappalainen, Hanna K.; Petäjä, Tuukka; Zaytzeva, Nina; Viisanen, Yrjö; Kotlyakov, Vladimir; Kasimov, Nikolay; Bondur, Valery; Matvienko, Gennady; Zilitinkevich, Sergej; Kulmala, Markku

    2014-05-01

    Pan-Eurasian Experiment (PEEX) is a new multidisciplinary research approach aiming at resolving the major uncertainties in the Earth system science and global sustainability questions in the Arctic and boreal Pan-Eurasian regions (Kulmala et al. 2011). The main goal of PEEX Research agenda is to contribute to solving the scientific questions that are specifically important for the Pan-Eurasian region in the coming years, in particular the global climate change and its consequences to nature and human society. Pan Eurasian region represents one the Earth most extensive areas of boreal forest (taiga) and the largest natural wetlands, thus being a significant source area of trace gas emissions, biogenic aerosol particles, and source and sink area for the greenhouse gas (GHG) exchange in a global scale (Guenther et al. 1995, Timkovsky et al. 2010, Tunved et al. 2006, Glagolev et al. 2010). One of the first activities of the PEEX initiative is to establish a process towards high level Pan-Eurasian Observation Networks. Siberian region is currently lacking a coordinated, coherent ground based atmosphere-ecosystem measurement network, which would be crucial component for observing and predicting the effects of climate change in the Northern Pan- Eurasian region The vision of the Pan-Eurasion network will be based on a hierarchical SMEAR-type (Stations Measuring Atmosphere-Ecosystem Interactions) integrated land-atmosphere observation system (Hari et al. 2009). A suite of stations have been selected for the Preliminary Phase of PEEX Observation network. These Preliminary Phase stations includes the SMEAR-type stations in Finland (SMEAR-I-II-II-IV stations), in Estonia (SMEAR-Järviselja) and in China (SMEAR-Nanjing) and selected stations in Russia and ecosystem station network in China. PEEX observation network will fill in the current observational gap in the Siberian region and bring the Siberian observation setup into international context with the with standardized or

  7. Intercomparison of stratospheric water vapor observed by satellite experiments: Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chiou, E. W.; McCormick, M. P.; McMaster, L. R.; Chu, W. P.; Larsen, J. C.; Rind, D.; Oltmans, S.

    1993-03-01

    This paper presents a comparison of the stratospheric water vapor measurements made by the satellite-borne sensors the Stratospheric Aerosol and Gas Experiment II (SAGE II), the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS), and the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. LIMS obtained data for 7 months between November 1978 and May 1979; ATMOS was carried on Shuttle and observed eight profiles from April 30 to May 6, 1985 at approximately 30°N and 50°S; and, SAGE II continues to make measurements since its launch in October 1984. For both 30°N and 50°S in May, the comparisons between SAGE II and ATMOS show agreement within the estimated combined uncertainty of the two experiments. Several important features identified by LIMS observations have been confirmed by SAGE II: a well-developed hygropause in the lower stratosphere at low- to mid-latitudes, a poleward latitudinal gradient, increasing water vapor mixing ratios with altitude in the tropics, and the transport of dry lower stratospheric water vapor upward and southward in May, and upward and northward in November. A detailed comparative study also indicates that the two previously suggested corrections for LIMS, a correction in tropical lower stratosphere due to a positive temperature bias and the correction above 28 km based on improved emissivities will bring LIMS measurements much closer to those of SAGE II. The only significant difference occurs at high southern latitudes in May below 18 km, where LIMS measurements are 2-3 ppmv greater. It should be noted that LIMS observations are from 16 to 50 km, ATMOS from 14 to 86 km, and SAGE II from mid-troposphere to 40 km. With multiyear coverage, SAGE II observations should be useful for studying tropospheric-stratospheric exchange, for stratospheric transport, and for preparing water vapor climatologies for the stratosphere and the upper troposphere.

  8. Saharan dust in Brazil and Suriname during the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) - Cooperative LBA Regional Experiment (CLAIRE) in March 1998

    NASA Astrophysics Data System (ADS)

    Formenti, P.; Andreae, M. O.; Lange, L.; Roberts, G.; Cafmeyer, J.; Rajta, I.; Maenhaut, W.; Holben, B. N.; Artaxo, P.; Lelieveld, J.

    2001-07-01

    Advection of Saharan dust was observed via chemical and optical measurements during March 1998 in Brazil and Suriname during the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)-Cooperative LBA Airborne Regional Experiment (CLAIRE)-98 experiment. In Brazil the dust outbreak produced an increase of a factor of 3 in the daily mean mass concentration (up to 26±7 μg m-3) of particles smaller than 10 μm equivalent aerodynamic diameter (EAD), and in the daily mean aerosol particle scattering coefficient σs (up to 26±8 Mm-1 STP, ambient humidity). Background levels of aerosol scattering (ambient) were σs ˜ 10 Mm-1. The effect of dust advection was evident for all major crustal elements (Al, Si, Ca, Ti, Mn, and Fe), as well as the sea-salt elements (Na, Cl, and S), as the dust layer was transported at low altitude (below 800 hPa). Coarse P and organic carbon (OC) concentrations were not influenced by the occurrence of dust, and were mainly emitted by the rain forest. The dry scattering mass efficiency of dust (particles smaller than 10 μm EAD) was estimated to be between 0.65 (±0.06) and 0.89 (±0.08) m2 g-1. Airborne profiles of aerosol scattering showed two distinct types of vertical structure in the dust layer over Suriname, either vertically uniform (15, 26 March), or plume-like (25 March). Dust layers extended generally up to 700 hPa, while scattering layers occasionally encountered at higher altitudes resulted from smoke emitted by biomass burning in Venezuela and Colombia. Observations in South America were supported by measurements in Israel and Tenerife (Canary Islands), where the dust outbreaks were also detected.

  9. Intercomparison of stratospheric water vapor observed by satellite experiments: Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy

    SciTech Connect

    Chiou, E.W.; Larsen, J.C. ); McCormick, M.P.; McMaster, L.R.; Chu, W.P. ); Rind, D. ); Oltmans, S. )

    1993-03-20

    This paper presents a comparison of the stratospheric water vapor measurements made by the satellite-borne sensors the Stratospheric Aerosol and Gas Experiment II (SAGE II), the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS), and the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. LIMS obtained data for 7 months between November 1978 and May 1979; ATMOS was carried on Shuttle and observed eight profiles from April 30 to May 6, 1985 at approximately 30[degrees]N and 50[degrees]S; and, SAGE II continues to make measurements since its launch in October 1984. For both 30[degrees]N and 50[degrees]S in May, the comparisons between SAGE II and ATMOS show agreement within the estimated combined uncertainty of the two experiments. Several important features identified by LIMS observations have been confirmed by SAGE II: a well-developed hygropause in the lower stratosphere at low- to mid-latitudes, a poleward latitudinal gradient, increasing water vapor mixing ratios with altitude in the tropics, and the transport of dry lower stratospheric water vapor upward and southward in May, and upward and northward in November. A detailed comparative study also indicates that the two previously suggested corrections for LIMS, a correction in tropical lower stratosphere due to a positive temperature bias and the correction above 28 km based on improved emissivities will bring LIMS measurements much closer to those of SAGE II. The only significant difference occurs at high southern latitudes in May below 18 km, where LIMS measurements are 2-3 ppmv greater. It should be noted that LIMS observations are from 16 to 50 km, ATMOS from 14 to 86 km, and SAGE II from mid-troposphere to 40 km. With multiyear coverage, SAGE II observations should be useful for studying tropospheric-stratospheric exchange, for stratospheric transport, and for preparing water vapor climatologies for the stratosphere and the upper troposphere. 32 refs., 14 figs., 2 tabs.

  10. Modeling the atmospheric and terrestrial water and energy cycles in the ScaleX experiment through a fully-coupled atmosphere-hydrology model

    NASA Astrophysics Data System (ADS)

    Senatore, Alfonso; Benjamin, Fersch; Thomas, Rummler; Caroline, Brosy; Christian, Chwala; Junkermann, Wolfgang; Ingo, Völksch; Harald, Kunstmann

    2016-04-01

    The TERENO preAlpine Observatory, comprising a series of observatory sites along an altitudinal gradient within the Ammer catchment (southern Bavaria, Germany), has been designed as an international research platform, open for participation and integration, and has been provided with comprehensive technical infrastructure to allow joint analyses of water-, energy- and nutrient fluxes. In June and July 2015 the operational monitoring has been complemented by the ScaleX intensive measurement campaign, where additional precipitation and soil moisture measurements, remote sensing measurements of atmospheric wind, humidity and temperature profiles have been performed, complemented by micro-light aircraft- and UAV-based remote sensing for three-dimensional pattern information. The comprehensive observations serve as validation and evaluation basis for compartment-crossing modeling systems. Specifically, the fully two-way dynamically coupled atmosphere-hydrology modeling system WRF-Hydro has been used to investigate the interplay of energy and water cycles at the regional scale and across the compartments atmosphere, stream, vadose zone and groundwater during the ScaleX campaign and to assess the closure of the budgets involved. Here, several high-resolution modeled hydro-meteorological variables, such as precipitation, soil moisture, river discharge and air moisture and temperature along vertical profiles are compared with observations from multiple sources, such as rain gauges and soil moisture networks, rain radars, stream gauges, UAV and a micro-light aircraft. Results achieved contribute to the objective of addressing questions on energy- and water-cycling within the TERENO-Ammer region at a very high scale and degree of integration, and provides hints on how well can observations constrain uncertainties associated with the modeling of atmospheric and terrestrial water and energy balances.

  11. Airborne atmospheric electricity experiments

    NASA Technical Reports Server (NTRS)

    Blakeslee, R. J.

    1985-01-01

    During the 1984 U2 spring flight program, lightning spectra were measured in the wavelengths from 380 nm to 900 nm with a temporal resolution of 5 ms. With this capability, researchers simultaneously acquired both visible near-infrared lightning spectra on a pulse to pulse basis, so that the spectral variability within a flash, as well as flash to flash variations, can be studied. Preliminary results suggest that important variations do occur, particularly in the strengths of the hydrogen and singly ionized nitrogen emission lines. Also, the results have revealed significant differences in the integrated energy distributions between the lightning spectra measured above clouds and the spectral measurements of cloud-to-ground lightning made at the ground. In particular, the ratio of the energy in the near-IR to that in the visible is around 1 to 2 for cloud top spectra versus about 1/3 for surface observations. Detailed analyses of the 1984 lightning spectral data is being conducted. This data should provide improved understanding about the optical transmission properties of thunderclouds and the physics of the lightning discharge process. Efforts continue on developing and testing background signal removal algorithms using U2 spectometer and optical array sensor day-flight data sets. The goal of this research is to develop an algorithm satisfying Lightning Mapper Sensor requirements.

  12. Airborne atmospheric electricity experiments

    NASA Technical Reports Server (NTRS)

    Blakeslee, R. J.

    1985-01-01

    During the 1984 U2 spring flight program, lightning spectra were measured in the wavelengths from 380 nm to 900 nm with a temporal resolution of 5 ms. With this capability, researchers simultaneously acquired both visible near-infrared lightning spectra on a pulse to pulse basis, so that the spectral variability within a flash, as well as flash to flash variations, can be studied. Preliminary results suggest that important variations do occur, particularly in the strengths of the hydrogen and singly ionized nitrogen emission lines. Also, the results have revealed significant differences in the integrated energy distributions between the lightning spectra measured above clouds and the spectral measurements of cloud-to-ground lightning made at the ground. In particular, the ratio of the energy in the near-IR to that in the visible is around 1 to 2 for cloud top spectra versus about 1/3 for surface observations. Detailed analyses of the 1984 lightning spectral data is being conducted. This data should provide improved understanding about the optical transmission properties of thunderclouds and the physics of the lightning discharge process. Efforts continue on developing and testing background signal removal algorithms using U2 spectometer and optical array sensor day-flight data sets. The goal of this research is to develop an algorithm satisfying Lightning Mapper Sensor requirements.

  13. Overview of the first Multicenter Airborne Coherent Atmospheric Wind Sensor (MACAWS) experiment: conversion of a ground-based lidar for airborne applications

    NASA Astrophysics Data System (ADS)

    Howell, James N.; Hardesty, R. Michael; Rothermel, Jeffrey; Menzies, Robert T.

    1996-11-01

    The first Multi center Airborne Coherent Atmospheric Wind Sensor (MACAWS) field experiment demonstrated an airborne high energy TEA CO2 Doppler lidar system for measurement of atmospheric wind fields and aerosol structure. The system was deployed on the NASA DC-8 during September 1995 in a series of checkout flights to observe several important atmospheric phenomena, including upper level winds in a Pacific hurricane, marine boundary layer winds, cirrus cloud properties, and land-sea breeze structure. The instrument, with its capability to measure 3D winds and backscatter fields, promises to be a valuable tool for climate and global change, severe weather, and air quality research. In this paper, we describe the airborne instrument, assess its performance, discuss future improvements, and show some preliminary results from the September experiments.

  14. Overview of the first Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) experiment: Conversion of a ground-based lidar for airborne applications

    SciTech Connect

    Howell, J.N.; Hardesty, R.M.; Rothermel, J.; Menzies, R.T.

    1996-12-31

    The first Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) field experiment demonstrated an airborne high energy TEA CO{sub 2} Doppler lidar system for measurement of atmospheric wind fields and aerosol structure. The system was deployed on the NASA DC-8 during September 1995 in a series of checkout flights to observe several important atmospheric phenomena, including upper level winds in a Pacific hurricane, marine boundary layer winds, cirrus cloud properties, and land-sea breeze structure. The instrument, with its capability to measure three-dimensional winds and backscatter fields, promises to be a valuable tool for climate and global change, severe weather, and air quality research. In this paper, the authors describe the airborne instrument, assess its performance, discuss future improvements, and show some preliminary results from September experiments.

  15. Response of sandstone to atmospheric heating during the STONE 5 experiment: Implications for the palaeofluid record in meteorites

    NASA Astrophysics Data System (ADS)

    Parnell, John; Mark, Darren; Brandstätter, Franz

    2008-09-01

    A 1 cm thick sandstone disk exposed to atmospheric re-entry on the heat shield of a spacecraft (the STONE 5 experiment) shows alteration of fluid inclusions compared to a control sample. The sandstone contained inclusions in quartz grains, feldspar grains and calcite cement before flight. After flight, inclusions in the feldspar were all decrepitated, few inclusions in calcite survived intact and they yielded widely varying microthermometric data, and the quartz inclusions also yielded disturbed microthermometric data. The quartz becomes less affected with depth below the surface, and extrapolation suggests would be unaffected at a depth of about 2 cm. These data show that fluid inclusion data from meteorites must be treated with caution, but that a genuine fluid record may survive in the interior portions. The possibility of thermal sterilization to 2 cm depth also implies that small meteorites may be unsuitable vehicles for the transfer of microbial life from one planetary body to another. As the interiors of larger meteorites tend to have very low porosity and permeability, microbial colonization would be difficult, and the potential for panspermia is accordingly low.

  16. Wind-Tunnel Experiments for Gas Dispersion in an Atmospheric Boundary Layer with Large-Scale Turbulent Motion

    NASA Astrophysics Data System (ADS)

    Michioka, Takenobu; Sato, Ayumu; Sada, Koichi

    2011-10-01

    Large-scale turbulent motions enhancing horizontal gas spread in an atmospheric boundary layer are simulated in a wind-tunnel experiment. The large-scale turbulent motions can be generated using an active grid installed at the front of the test section in the wind tunnel, when appropriate parameters for the angular deflection and the rotation speed are chosen. The power spectra of vertical velocity fluctuations are unchanged with and without the active grid because they are strongly affected by the surface. The power spectra of both streamwise and lateral velocity fluctuations with the active grid increase in the low frequency region, and are closer to the empirical relations inferred from field observations. The large-scale turbulent motions do not affect the Reynolds shear stress, but change the balance of the processes involved. The relative contributions of ejections to sweeps are suppressed by large-scale turbulent motions, indicating that the motions behave as sweep events. The lateral gas spread is enhanced by the lateral large-scale turbulent motions generated by the active grid. The large-scale motions, however, do not affect the vertical velocity fluctuations near the surface, resulting in their having a minimal effect on the vertical gas spread. The peak concentration normalized using the root-mean-squared value of concentration fluctuation is remarkably constant over most regions of the plume irrespective of the operation of the active grid.

  17. Fine-Structure Measurements of Oxygen A Band Absorbance for Estimating the Thermodynamic Average Temperature of the Earth's Atmosphere: An Experiment in Physical and Environmental Chemistry

    ERIC Educational Resources Information Center

    Myrick, M. L.; Greer, A. E.; Nieuwland, A.; Priore, R. J.; Scaffidi, J.; Andreatta, Daniele; Colavita, Paula

    2006-01-01

    The experiment describe the measures of the A band transitions of atmospheric oxygen, a rich series of rotation-electronic absorption lines falling in the deep red portion of the optical spectrum and clearly visible owing to attenuation of solar radiation. It combines pure physical chemistry with analytical and environmental science and provides a…

  18. Studies of land-cover, land-use, and biophysical properties of vegetation in the Large Scale Biosphere Atmosphere experiment in Amazonia.

    Treesearch

    Dar A. Robertsa; Michael Keller; Joao Vianei Soares

    2003-01-01

    We summarize early research on land-cover, land-use, and biophysical properties of vegetation from the Large Scale Biosphere Atmosphere (LBA) experiment in Amazoˆnia. LBA is an international research program developed to evaluate regional function and to determine how land-use and climate modify biological, chemical and physical processes there. Remote sensing has...

  19. Fine-Structure Measurements of Oxygen A Band Absorbance for Estimating the Thermodynamic Average Temperature of the Earth's Atmosphere: An Experiment in Physical and Environmental Chemistry

    ERIC Educational Resources Information Center

    Myrick, M. L.; Greer, A. E.; Nieuwland, A.; Priore, R. J.; Scaffidi, J.; Andreatta, Daniele; Colavita, Paula

    2006-01-01

    The experiment describe the measures of the A band transitions of atmospheric oxygen, a rich series of rotation-electronic absorption lines falling in the deep red portion of the optical spectrum and clearly visible owing to attenuation of solar radiation. It combines pure physical chemistry with analytical and environmental science and provides a…

  20. Atmospheric deposition and re-emission of mercury estimated in a prescribed forest-fire experiment in Florida, USA

    Treesearch

    Ralph J. DiCosty; Mac A. Callaham; John A. Stanturf

    2006-01-01

    Prescribed fires are likely to re-emit atmospherically deposited mercury (Hg), and comparison of soil Hg storage in areas affected by prescribed fire to that in similar unburned areas may provide cross-validating estimates of atmospheric Hg deposition. Prescribed fires are common in the southeastern United States (US), a region of relatively high Hg deposition compared...

  1. Sea level variability in the eastern tropical Pacific as observed by TOPEX and Tropical Ocean-Global Atmosphere Tropical Atmosphere-Ocean Experiment

    NASA Technical Reports Server (NTRS)

    Giese, Benjamin S.; Carton, James A.; Holl, Lydia J.

    1994-01-01

    Sea surface height measurements from the TOPEX altimeter and dynamic height from Tropical Ocean-Global Atmosphere Tropical Atmosphere-Ocean (TOGA TAO) moorings are used to explore sea level variability in the northeastern tropical Pacific Ocean. Afetr the annual harmonic is removed, there are two distinct bands of variability: one band is centered at 5 deg N to 7 deg N and extends from 165 deg W to 110 deg W, and the other band is centered at 10 deg N to 12 deg N and extends from 120 deg W to the coast of Central America. The correspondence between the two independent observation data sets at 5 deg N is excellent with correlations of about 90%. The variability at 5 deg-7 deg N is identified as instability waves formed just south of the North Equatorial Countercurrent during the months of July and March. Wave amplitudes are largest in the range of longitudes 160 deg-140 deg W, where they can exceed 10 cm. The waves disappear when the equatorial current system weakens, during the months of March and May. The variability at 11 deg N in 1993 has the form of anticyclone eddies. These eddies propagate westward at a speed of about 17 cm/s, consistent with the dispersion characteristics of free Rossby waves. The eddies are shown to have their origin near the coast of central America during northern fall and winter. Their formation seems to result from intense wind bursts across the Gulfs of Tehuantepec and Papagayo which generate strong anticyclonic ocean eddies. The disappearance of the eddies in the summer of 1993 coincidences with the seasonal intensification of equatorial currents. Thus the variability at 11 deg N has very little overlap in time with the variability at 5 deg N.

  2. Multiple signal propagation at the tropopause of the Venusian atmosphere: new insights from the Radio Science Experiment (VeRa) onboard Venus Express

    NASA Astrophysics Data System (ADS)

    Herrmann, Maren; Oschlisniok, Janusz; Remus, Stefan; Tellmann, Silvia; Häusler, Bernd; Pätzold, Martin

    2016-10-01

    The rapid change of the refractive index over a short altitude range in a planetary atmosphere can lead to multi-path effects when sounding the atmosphere with radio waves. The Radio Science Experiment (VeRa) [1,2] onboard Venus Express sounded the Venusian atmosphere from 90 km downward to 40 km altitude[3,4]. More than 800 profiles of temperature, pressure and neutral number density could be retrieved which cover almost all local times and latitudes. A specially developed analysis method based on the VeRa open loop receiving technique deciphers the multi-path effect and identifies an inversion layer near the tropopause at an altitude of about 60km. This layer is of particular interest - it separates the stratified troposphere from the highly variable mesosphere and can be a likely location for the formation of gravity waves [5]. The new retrieval method shows an inversion layer up to 15 K colder than commonly thought. Local time and latitude dependence including the influence of the spacecraft trajectory on this effect will be discussed. These results will contribute to a consistent picture of the Venus' thermal atmosphere structure and therefore help to improve atmospheric models.[1] Häusler, B. et al: 'Radio science investigations by VeRa onboard the Venus Express spacecraft' Planetary and Space Science 54, 2006[2] Häusler, B. et al, 'Venus Atmospheric, Ionospheric, Surface and Interplanetery Radio-Wave Propagation Studies with the VeRa Radio Science experiment' Eur. Space Agencys, Spec. Publ., ESA SP 1295, 2007[3] Pätzold, M. et al: 'The structure of Venus' middle atmosphere and ionosphere', Nature 450, 2007[4] Tellmann, S. et al : 'Structure of the Venus neutral atmosphere as observed by the Radio Science experiment VeRa on Venus Express', Journal of Geophysical Research 114, 2009[5] Tellmann, S. et al: 'Small-scale temperature fluctuations seen by the VeRa Radio Science Experiment on Venus Express' Icarus 221, 2012.

  3. Atmospheric Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Giacomelli, G.; Giorgini, M.

    2005-04-01

    The latest results from the Soudan 2, MACRO and SuperKamiokande experiments on atmospheric neutrino oscillations are summarised and discussed. In particular a discussion is made on the Monte Carlo simulations used for the atmospheric neutrino flux.

  4. The New Horizons Radio Science Experiment: Expected Performance in Measurements of Pluto's Atmospheric Structure, Surface Pressure, and Surface Temperature

    NASA Astrophysics Data System (ADS)

    Hinson, D. P.; Linscott, I.; Woods, W. W.; Tyler, G. L.; Bird, M. K.; Paetzold, M.; Strobel, D. F.

    2014-12-01

    The New Horizons (NH) payload includes a Radio Science Experiment (REX) for investigating key characteristics of Pluto and Charon during the upcoming flyby in July 2015. REX flight equipment augments the NH radio transceiver used for spacecraft communications and tracking. The REX hardware implementation requires 1.6 W and 160 g. This presentation will focus on the final design and the predicted performance of two high-priority observations. First, REX will receive signals from a pair of 70-m antennas on Earth - each transmitting 20 kW at 4.2-cm wavelength - during a diametric radio occultation by Pluto. The data recorded by REX will reveal the surface pressure, the temperature structure of the lower atmosphere, and the surface radius. Second, REX will measure the thermal emission from Pluto at 4.2-cm wavelength during two linear scans across the disk at close range when both the dayside and the nightside are visible, allowing the surface temperature and its spatial variations to be determined. Both scans extend from limb to limb with a resolution of about 10 pixels; one bisects Pluto whereas the second crosses the winter pole. We will illustrate the capabilities of REX by reviewing the method of analysis and the precision achieved in a lunar occultation observed by New Horizons in May 2011. Re-analysis of radio occultation measurements by Voyager 2 at Triton is also under way. More generally, REX objectives include a radio occultation search for Pluto's ionosphere; examination of Charon through both radio occultation and radiometry; a search for a radar echo from Pluto's surface; and improved knowledge of the Pluto system mass and the Pluto-Charon mass ratio from a combination of two-way and one-way Doppler frequency measurements.

  5. Summary of the results from the Lunar Dust Experiment (LDEX) onboard the Lunar Atmosphere and Dust Environment (LADEE) Mission

    NASA Astrophysics Data System (ADS)

    Horanyi, Mihaly

    2016-07-01

    The Lunar Dust Experiment (LDEX) onboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission (9/2013 - 4/2014) discovered a permanently present dust cloud engulfing the Moon. The size, velocity, and density distributions of the dust particles are consistent with ejecta clouds generated from the continual bombardment of the lunar surface by sporadic interplanetary dust particles. Intermittent density enhancements were observed during several of the annual meteoroid streams, especially during the Geminids. LDEX found no evidence of the expected density enhancements over the terminators where electrostatic processes were predicted to efficiently loft small grains. LDEX is an impact ionization dust detector, it captures coincident signals and full waveforms to reliably identify dust impacts. LDEX recorded average impact rates of approximately 1 and 0.1 hits/minute of particles with impact charges of q > 0.5 and q > 5 fC, corresponding to particles with radii of a > 0.3 and a> 0.7~μm, respectively. Several of the yearly meteor showers generated sustained elevated levels of impact rates, especially if their radiant direction intersected the lunar surface near the equatorial plane, greatly enhancing the probability of crossing their ejecta plumes. The characteristic velocities of dust particles in the cloud are on the order of ~100 m/s which we neglect compared to the typical spacecraft speeds of 1.6 km/s. Hence, with the knowledge of the spacecraft orbit and attitude, impact rates can be directly turned into particle densities as functions of time and position. LDEX observations are the first to identify the ejecta clouds around the Moon sustained by the continual bombardment of interplanetary dust particles. Most of the dust particles generated in impacts have insufficient energy to escape and follow ballistic orbits, returning to the surface, 'gardening' the regolith. Similar ejecta clouds are expected to engulf all airless planetary objects, including

  6. A Physical Experiment to determine the Impact of Atmospheric Condensation of Water Vapor on Surface Air Movement

    NASA Astrophysics Data System (ADS)

    Bunyard, P. P.; Nechev, P.

    2013-12-01

    A physical experiment, in which atmospheric air is enclosed in two interconnecting 4.8-metre high insulated PVC columns, consistently gives results showing that the condensation of water vapor, precipitated by means of refrigeration coils, gives rise to detectable air movements, with air speeds of up to 0.1 m/s. Once the compressor, sited well away from the two columns, is shut down, heavy drops of precipitated water are obtained which funnel into a flask for collection and measurement. The results in kg.m-2 (mm) from the 20 m3 volume of enclosed air accord well (>90%) with the physical calculations based on water vapor as an ideal gas. Air flow, resulting from the highly localized condensation, is measured through the movement of light-weight gauzes and an anemometer. It has a circulation time of some two minutes, such that both columns show cooling and a significant reduction in specific humidity from 0.01 to 0.005 (kg water vapor to kg dry air, r) with a drop in relative humidity of up to 40 per cent. Air flow is minimal during the control, non-refrigeration period of the experiment but becomes substantial within a minute of the compressor being switched on. The negative partial pressure change peaks at as much as 0.4 Pa/s during the first 30 minutes but reduces to approx. 0.08 Pa/s during the latter part of the 110 minute- long experiment. Airflow displays an inverse relationship to the partial pressure change, initially rising rapidly and then reducing before returning to zero once refrigeration has been switched off. Inverse correlations of up to 0.8 or higher between the partial pressure reduction and the airflow are obtained routinely. Semi-aquatic vegetation from the nearby marshland enhances precipitation, suggesting that evapotranspiration adds significantly to humidity. Without vegetation the condensation rate is 0.06 to 0.07 millimol.m-3.s-1 on average compared with 0.11 when vegetation is present. Cooling, by some 2°C, combined with a reduction in

  7. A Physical Experiment to determine the Impact of Atmospheric Condensation of Water Vapour on Surface Air Movement

    NASA Astrophysics Data System (ADS)

    Bunyard, Peter

    2014-05-01

    A physical experiment, in which atmospheric air is enclosed in two interconnecting 4.8-metre high insulated PVC columns, consistently gives results showing that the condensation of water vapor, precipitated by means of refrigeration coils, gives rise to detectable air movements, with air speeds of up to 0.1 m/s. Once the compressor, sited well away from the two columns, is shut down, heavy drops of precipitated water are obtained which funnel into a flask for collection and measurement. The results in kg.m-2 (mm) from the 20 m3 volume of enclosed air accord well (>90%) with the physical calculations based on water vapour as an ideal gas. Air flow, resulting from the highly localized condensation, is measured through the movement of light-weight gauzes and an anemometer. It has a circulation time of some two minutes, such that both columns show cooling and a significant reduction in specific humidity from 0.01 to 0.005 (kg water vapour to kg dry air, r) with a drop in relative humidity of up to 40 per cent. Air flow is minimal during the control, non-refrigeration period of the experiment but becomes substantial within a minute of the compressor being switched on. The negative partial pressure change peaks at as much as 0.4 Pa/s during the first 30 minutes but reduces to approx.0.08 Pa/s during the latter part of the 110 minute-long experiment. Airflow displays an inverse relationship to the partial pressure change, initially rising rapidly and then reducing before returning to zero once refrigeration has been switched off. Inverse correlations of up to 0.8 or higher between the partial pressure reduction and the airflow are obtained routinely. Semi-aquatic vegetation from the nearby marshland enhances precipitation, suggesting that evapotranspiration adds significantly to humidity. Without vegetation the condensation rate is 0.06 to 0.07 millimol.m-3.s-1 on average compared with 0.11 when vegetation is present. Cooling, by some 2°C, combined with a reduction in

  8. Initial Verification of the GPS-LEO Occultation Technique of Mapping the Atmosphere with the GPS-MET Experiment

    NASA Technical Reports Server (NTRS)

    Hajj, G. A.; Kursinski, E. R.; Bertiger, W. I.; Leroy, S. S.; Romans, L. J.; Schofield, J. T.

    1995-01-01

    The radio occultation technique was first used to observe Earth's atmosphere in April 1995 when a high performance Global Positioning System (GPS) receiver was placed into a low-Earth orbit. When a signal from the GPS travels through the ionosphere and the neutral atmosphere, and is received by a low-Earth orbiter (LEO) satellite, occultation data is generated. How that data is analyzed is presented.

  9. High resolution infrared spectroscopy from space: A preliminary report on the results of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment on Spacelab 3

    NASA Technical Reports Server (NTRS)

    Farmer, Crofton B.; Raper, Odell F.

    1987-01-01

    The ATMOS (Atmospheric Trace Molecule Spectroscopy) experiment has the broad purpose of investigating the physical structure, chemistry, and dynamics of the upper atmosphere through the study of the distributions of the neutral minor and trace constituents and their seasonal and long-term variations. The technique used is high-resolution infrared absorption spectroscopy using the Sun as the radiation source, observing the changes in the transmission of the atmosphere as the line-of-sight from the Sun to the spacecraft penetrates the atmosphere close to the Earth's limb at sunrise and sunset. During these periods, interferograms are generated at the rate of one each second which yield, when transformed, high resolution spectra covering the 2.2 to 16 micron region of the infrared. Twenty such occultations were recorded during the Spacelab 3 flight, which have produced concentration profiles for a large number of minor and trace upper atmospheric species in both the Northern and Southern Hemispheres. Several of these species have not previously been observed in spectroscopic data. The data reduction and analysis procedures used following the flight are discussed; a number of examples of the spectra obtained are shown, and a bar graph of the species detected thus far in the analysis is given which shows the altitude ranges for which concentration profiles were retrieved.

  10. Simulation of large scale motions and small scale structures in planetary atmospheres and oceans: From laboratory to space experiments on ISS

    NASA Astrophysics Data System (ADS)

    Egbers, Christoph; Futterer, Birgit; Zaussinger, Florian; Harlander, Uwe

    2014-05-01

    Baroclinic waves are responsible for the transport of heat and momentum in the oceans, in the Earth's atmosphere as well as in other planetary atmospheres. The talk will give an overview on possibilities to simulate such large scale as well as co-existing small scale structures with the help of well defined laboratory experiments like the baroclinic wave tank (annulus experiment). The analogy between the Earth's atmosphere and the rotating cylindrical annulus experiment only driven by rotation and differential heating between polar and equatorial regions is obvious. From the Gulf stream single vortices seperate from time to time. The same dynamics and the co-existence of small and large scale structures and their separation can be also observed in laboratory experiments as in the rotating cylindrical annulus experiment. This experiment represents the mid latitude dynamics quite well and is part as a central reference experiment in the German-wide DFG priority research programme ("METSTRÖM", SPP 1276) yielding as a benchmark for lot of different numerical methods. On the other hand, those laboratory experiments in cylindrical geometry are limited due to the fact, that the surface and real interaction between polar and equatorial region and their different dynamics can not be really studied. Therefore, I demonstrate how to use the very successful Geoflow I and Geoflow II space experiment hardware on ISS with future modifications for simulations of small and large scale planetary atmospheric motion in spherical geometry with differential heating between inner and outer spheres as well as between the polar and equatorial regions. References: Harlander, U., Wenzel, J., Wang, Y., Alexandrov, K. & Egbers, Ch., 2012, Simultaneous PIV- and thermography measurements of partially blocked flow in a heated rotating annulus, Exp. in Fluids, 52 (4), 1077-1087 Futterer, B., Krebs, A., Plesa, A.-C., Zaussinger, F., Hollerbach, R., Breuer, D. & Egbers, Ch., 2013, Sheet-like and

  11. Development of Experience-based Learning about Atmospheric Environment with Quantitative Viewpoint aimed at Education for Sustainable Development

    NASA Astrophysics Data System (ADS)

    Saitoh, Y.; Tago, H.

    2014-12-01

    The word "ESD (Education for Sustainable Development)" has spread over the world in UN decade (2005 - 2014), and the momentum of the educational innovation aimed at ESD also has grown in the world. Especially, environmental educations recognized as one of the most important ESD have developed in many countries including Japan, but most of those are still mainly experiences in nature. Those could develop "Respect for Environment" of the educational targets of ESD, however we would have to take a further step in order to enhance "Ability of analysis and thinking logically about the environment" which are also targets of ESD.Thus, we developed experienced-learning program about atmospheric particulate matter (PM2.5), for understanding the state of the environment objectively based on quantitative data. PM2.5 is known for harmful, and various human activities are considered a source of it, therefore environmental standards for PM2.5 have been established in many countries. This program was tested on junior high school students of 13 - 15 years old, and the questionnaire survey also was conducted to them before and after the program for evaluating educational effects. Students experienced to measure the concentration of PM2.5 at 5 places around their school in a practical manner. The measured concentration of PM2.5 ranged from 19 to 41 μg/m3/day, that value at the most crowded roadside exceeded Japan's environmental standard (35 μg/m3/day). Many of them expressed "Value of PM2.5 is high" in their individual discussion notes. As a consistent with that, the answer "Don't know" to the question "What do you think about the state of the air?" markedly decreased after the program, on the other hand the answer "Pollution" to the same question increased instead. From above-mentioned, it was considered that they could judge the state of the air objectively. Consequently, the questionnaire result "Concern about Air Pollution" increased significantly after the program compared

  12. Dielectric Barrier Discharges in Helium at Atmospheric Pressure: Experiments and Model in the Needle-Plane Geometry

    NASA Astrophysics Data System (ADS)

    Radu, Ion; Bartnikas, Raymond; Wertheimer, Michael

    2002-10-01

    We present an experimental and theoretical modeling study of "dielectric barrier discharges" (DBD) at atmospheric pressure in a needle-plane configuration. Synchronous, Ultra High Speed Imaging (UHSI, using a Princeton Instruments PI-MAX 512RB Digital ICCD Camera System) and real-time dual detection (optical-electrical) diagnostics have been carried out in a flow of He. A phase-resolved synchronizing circuit was used to trigger the ICCD camera's shutter for durations varying from 2 ns up to 100 ms. All diagnostics, including the PI-MAX images, could be precisely synchronized and processed on a PC computer. The high voltage electrode was a steel needle with a sharp point of precisely-machined radius, while a thin (1.6 mm) ceramic (Al2O3) plate with a metallized bottom surface was used as the ground electrode. Three different situations have been studied, namely (i) the bare Al2O3, and with an ultra-thin coatings of (ii) graphite (a semiconductor) or (iii) metal, the latter two at floating potential. The purpose of these experiments was to investigate possible effects of surface charging on the discharge behavior [1]. The axial [y(t)] and radial [x(t)] time evolutions of the discharge have been measured by UHSI, plotted, and found to differ very significantly among cases (i) to (iii). In the needle-plane configuration (like in the plane-plane case), the DBD is characterized by a single pulse per half-period of the applied voltage. A two-dimensional model of the needle-plane discharge, based upon the continuity equations for electrons, ions, excited particles, and the Poisson equation, is developed; it assumes a low degree of ionization, so that the transport coefficients of the gas are uniquely determined by the local electric field [2]. In order to determine the electric field and the electrical potential in the (hyperboloidal) needle-plane geometry, the finite element method is used. We have found excellent agreement between measured and calculated [y(t)] and [x

  13. Photochemistry of CO and H2O - Analysis of laboratory experiments and applications to the prebiotic earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Wen, Jun-Shan; Pinto, Joseph P.; Yung, Yuk L.

    1989-01-01

    The role photochemical reactions in the early earth's atmosphere played in the prebiotic synthesis of simple organic molecules was examined, extending an earlier calculation of formaldehyde production rates to more reduced carbon species, such as methanol, methane, and acetaldehyde. The experimental results of Bar-Nun and Chang (1983) are simulated as an aid in the construction of the photochemical scheme and as a way of validating the model. The results indicate that some fraction of CO2 and H2 present in the primitive atmosphere could have been converted to simple organic molecules. The exact amount is dependent on the partial pressure of CO2 and H2 in the atmosphere and on what assumptions are made concerning the shape of the absorption spectra of CO2 and H2O.

  14. Analysis of the feasibility of an experiment to measure carbon monoxide in the atmosphere. [using remote platform interferometry

    NASA Technical Reports Server (NTRS)

    Bortner, M. H.; Alyea, F. N.; Grenda, R. N.; Liebling, G. R.; Levy, G. M.

    1973-01-01

    The feasibility of measuring atmospheric carbon monoxide from a remote platform using the correlation interferometry technique was considered. It has been determined that CO data can be obtained with an accuracy of 10 percent using this technique on the first overtone band of CO at 2.3 mu. That band has been found to be much more suitable than the stronger fundamental band at 4.6 mu. Calculations for both wavelengths are presented which illustrate the effects of atmospheric temperature profiles, inversion layers, ground temperature and emissivity, CO profile, reflectivity, and atmospheric pressure. The applicable radiative transfer theory on which these calculations are based is described together with the principles of the technique.

  15. Photochemistry of CO and H2O - Analysis of laboratory experiments and applications to the prebiotic earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Wen, Jun-Shan; Pinto, Joseph P.; Yung, Yuk L.

    1989-01-01

    The role photochemical reactions in the early earth's atmosphere played in the prebiotic synthesis of simple organic molecules was examined, extending an earlier calculation of formaldehyde production rates to more reduced carbon species, such as methanol, methane, and acetaldehyde. The experimental results of Bar-Nun and Chang (1983) are simulated as an aid in the construction of the photochemical scheme and as a way of validating the model. The results indicate that some fraction of CO2 and H2 present in the primitive atmosphere could have been converted to simple organic molecules. The exact amount is dependent on the partial pressure of CO2 and H2 in the atmosphere and on what assumptions are made concerning the shape of the absorption spectra of CO2 and H2O.

  16. Land-atmosphere interaction and disaster-causing process of drought in northern China: observation and experiment (DroughtPEX_China)

    NASA Astrophysics Data System (ADS)

    Li, Yaohui

    2017-04-01

    Drought is one of the most common and frequent nature disasters in the world, particularly in China under the continental monsoonal climate with great variation. About thirty percent of economic loss caused by natural disasters is contributed by droughts in China, which is by far the most damaging weather disasters because of its long duration and extensive hazard areas. Droughts not only have a serious impact on the agriculture, water resources, ecology, natural environment, but also seriously affect the socio-economic such as human health, energy and transportation. Worsely, under the background of climate change, droughts in show increases in frequency, duration and scope in many places around the world, particularly northern China. Nowadays, droughts have aroused extensive concern of the scientists, governments and international community, and became one of the important scientific issues in geoscience research. However, most of researches on droughts in China so far were focused on the causes or regulars of one type of droughts (the atmosphere, agriculture or hydrological) from the perspective of the atmospheric circulation anomalies. Few of them considered a whole cycle of the drought-forming process from atmosphere-land interaction to agricultural/ecological one in terms of the land-atmosphere interaction; meanwhile, the feedback mechanism with the drought and land-atmosphere interaction is still unclear as well. All of them is because of lack of the relevant comprehensive observation experiment. "Land-atmosphere interaction and disaster-causing process of drought in northern China: observation and experiment" (DroughtPEX_China)is just launched in this requirement and background. DroughtPEX_China is supported by Special Scientific Research Fund of Public Welfare Industry (Meteorological) of China (Grant No.GYHY201506001)—"Drought Meteorology Scientific Research Project—the disaster-causing process and mechanism of drought in northern China". This project

  17. Recherche De Correlations Temporelles Des Muons Cosmiques Avec Macro Et Perte D'Energie Des Nuclearites

    NASA Astrophysics Data System (ADS)

    Moussa, A.

    2009-11-01

    The first parts of the thesis recalls the main features of the large MACRO experiment at the underground Gran Sasso Laboratory. It then describes the atmospheric muons measured by the experiment and the selection criteria to obtain and analyze a large sample of cosmic muons. The time series of MACRO muons was analyzed with two complementary approaches: search for the occurrence of bursts of muon events and search for periodicities in the muon time distribution. The Scan Statistics method was used in the first case and the Lomb-Scargle spectral analysis in the second case. The two techniques complete early analyses performed with "folding" methods. It is confirmed that the seasonal variation is the dominant periodic variation, and one also confirms the solar diurnal and sidereal modulations. A separate study concerns the analysis of the energy losses of the hypothetical Nuclearites in different materials and detectors; their importance for the searches performed by the MACRO and the SLIM experiments is discussed.

  18. Local coupling (LoCo) vs. large-scale coupled (LsCo) land-atmosphere interactions in idealized experiments

    NASA Astrophysics Data System (ADS)

    Gentine, P.; Lintner, B. R.; Findell, K. L.; Rochetin, N.; Sobel, A. H.; Anber, U. M.

    2014-12-01

    We will present two idealized epxeriments/methodologies to investigate local (LoCo) and large-scale (LsCo) coupling between the surface and the atmsophere: the contiental Radiative-Convective Equilibrium (RCE) and the continental Weak Temperature Gradient (WTG). The RCE defines an equilibrium state of coupling between the surafce and the atmosphere isolated from any large-scale dependence, which were investigated within the single column model of the Laboratoire de Meteorologie Dynamique (LMD) coupled to a simple bucket land model. This studies emphasizes the role of low-level cloud and the diurnal cylce of the boundary layer on the final state of the system. In the WTG we investigate the coupling between the surface and the atmosphere during the dry and wet season of the Amazon with the WRF model coupled to the NOAH land-surface model. Large-scale coupling is obtained with the WTG. The dry and wet season demonstrate very fundamental behavior: in the dry season deep convection is generated by radiative cooling in the higher troposhere and is disconnected from the surface. In the wet season the coupling between the surface and the atmosphere is much tighter. We suggest that the WTG is a powerful tool to investigate the coupling between the surface and the atmosphere, which solves two major issues: the limited resolution of convection in GCMs and the lack of large-scale coupling in CRM. Later investigation will look at the effect of deforestation, water table and distance from the ocean.

  19. Atmospheric CO2 and soil extracellular enzyme activity: A meta-analysis and CO2 gradient experiment

    USDA-ARS?s Scientific Manuscript database

    Rising atmospheric CO2 concentrations may alter carbon and nutrient cycling and microbial processes in terrestrial ecosystems. One of the primary ways that microbes interact with soil organic matter is through the production of extracellular enzymes, which break down large, complex organic molecules...

  20. Atmospheric CO2 level affects plants' carbon use efficiency: insights from a 13C labeling experiment on sunflower stands

    NASA Astrophysics Data System (ADS)

    Gong, Xiaoying; Schäufele, Rudi; Schnyder, Hans

    2015-04-01

    The increase of atmospheric CO2 concentration has been shown to stimulate plant photosynthesis and (to a lesser extent) growth, thereby acting as a possible sink for the additional atmospheric CO2. However, this effect is dependent on the efficiency with which plants convert atmospheric carbon into biomass carbon, since a considerable proportion of assimilated carbon is returned to the atmosphere via plant respiration. As a core parameter for carbon cycling, carbon use efficiency of plants (CUE, the ratio of net primary production to gross primary production) quantifies the proportion of assimilated carbon that is incorporated into plant biomass. CUE has rarely been assessed based on measurements of complete carbon balance, due to methodological difficulties in measuring respiration rate of plants in light. Moreover, foliar respiration is known to be inhibited in light, thus foliar respiration rate is generally lower in light than in dark. However, this phenomenon, termed as inhibition of respiration in light (IRL), has rarely been assessed at the stand-scale and been incorporated into the calculation of CUE. Therefore, how CUE responses to atmospheric CO2 levels is still not clear. We studied CUE of sunflower stands grown at sub-ambient CO2 level (200 μmol mol-1) and elevated CO2 level (1000 μmol mol-1) using mesocosm-scale gas exchange facilities which enabled continuous measurements of 13CO2/12CO2 exchange. Appling steady-state 13C labeling, fluxes of respiration and photosynthesis in light were separated, and tracer kinetic in respiration was analyzed. This study provides the first data on CUE at a mesocosm-level including respiration in light in different CO2 environments. We found that CUE of sunflower was lower at an elevated CO2 level than at a sub-ambient CO2 level; and the ignorance of IRL lead to erroneous estimations of CUE. Variation in CUE at atmospheric CO2 levels was attributed to several mechanisms. In this study, CO2 enrichment i) affected the

  1. Altitude dependent Titan/fs atmospheric chemistry: UV irradiation experiments at low temperature combined with cold plasma irradiation

    NASA Astrophysics Data System (ADS)

    Imanaka, H.; Khare, B. N.; Bakes, E. L. O.; Sekine, Y.; McKay, C. P.; Cruikshank, D. P.; McGuigan, M.; Waite, J. H.; Sacks, R.

    2004-11-01

    Active organic chemistry in Titan/fs atmosphere forming organic haze and various gas species is induced by solar UV radiation and charged particle irradiations. The main available energy sources depend on altitude, so that the physical and chemical properties of the haze and the condensates of hydrocarbons and nitriles may depend on altitude. To understand Titan/fs atmospheric chemistry as a function of altitudes, we have conducted laboratory simulations using UV irradiation and/or charged particle irradiation as energy sources. We utilize GCMS for analyzing the chemical components of gas products, condensed ice mixtures, and pylorizates from tholins. First, the gas products and tholins were formed from methane-nitrogen gas mixture through cold plasma irradiation. This simulates the upper atmosphere of Titan where methane and nitrogen are dissociated by short UV and charge particle irradiations. The gas products were fractionally condensed by cold traps at several temperatures. More than 100 gas species were detected by GCMS, including saturated and unsaturated aliphatic hydrocarbons, substituted aromatics, nitriles, nitrogen heteroaromatics such as pyrrole, pyridine, pyrazine, pyrazole. Nitrogen containing compounds larger than (C+N)4 were mainly detected from ice mixture condensed at 196 K. Py-GCMS analysis of tholin revealed various alkanes, nitriles, and substituted aromatics as well as substituted pyrroles. In the lower stratosphere of Titan, various gas species diffused from the upper atmosphere may undergo further photolysis by long UV. To simulate the lower stratosphere, the gas products from cold plasma were further irradiated by long UV lights (> about 150 nm) at about 196 K and 1 mbar. The unsaturated hydrocarbons were reduced and formed the tholin materials, although the production rate was very small. Our results can be directly applied to the Huygens mission in 2005, which will measure gas compositions (GCMS) and aerosol particles (ACP-GCMS) at

  2. Titan Ice and Dust Experiment (TIDE): Detection and Analysis of Compounds of Interest to Astrobiology in the Lower Atmosphere and Surface of Titan

    NASA Technical Reports Server (NTRS)

    Kojiro, Daniel R.; Holland Paul M.; Stimac, Robert M.; Kaye, William J.; Takeruchi, Noreshige

    2004-01-01

    The Titan Orbiter Aerorover Mission (TOAM) is a proposed concept for the Solar System Exploration Visions Mission, Titan Explorer, a follow-on to the Cassini-Huygens mission. TOAM would use a Titan polar orbiter and a lighter-than-air aerorover to investigate the surface and atmosphere of Titan. Astrobiology issues will be addressed though TOAM investigations including, for example: Distribution and composition of organics (atmospheric, aerosol, surface); Organic chemical processes, their chemical context and energy sources; and Seasonal variations and interactions of the atmosphere and surface. The TIDE instrument will perform in-situ analyses to obtain comprehensive and sensitive molecular and elemental assays of volatile organics in the atmosphere, oceans and surface. TIDE chemical analyses are conducted by a Gas Chromatograph-Ion Mobility Spectrometer (GC-IMS). This TIDE GC-IMS was a component of the mini-Cometary Ice and Dust Experiment (mini-CIDEX) developed for the chemical analysis of a cometary environment. Both the GC and helium IMS of mini-CIDEX have been further developed to better meet the analytical and operational requirements of the TOAM. application. A Micro-ElectroMechanical System (MEMS) GC and Mini-Cell helium IMS are under development to replace their respective mini-CIDEX components, providing similar or advanced analytical capabilities.

  3. On the Assessment and Uncertainty of Atmospheric Trace Gas Burden Measurements with High Resolution Infrared Solar Occultation Spectra from Space by the ATMOS Experiment

    NASA Technical Reports Server (NTRS)

    Abrams, M. C.; Chang, A. Y.; Gunson, M. R.; Abbas, M. M.; Goldman, A.; Irion, F. W.; Michelsen, H. A.; Newchurch, M. J.; Rinsland, C. P.; Stiller, G. P.; Zander, R.

    1996-01-01

    The Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument is a high resolution Fourier transform spectrometer that measures atmospheric composition from low Earth orbit with infrared solar occultation sounding in the limb geometry. Following an initial flight in 1985, ATMOS participated in the Atmospheric Laboratory for Applications and Science (ATLAS) 1, 2, and 3 Space Shuttle missions in 1992, 1993, and 1994 yielding a total of 440 occultation measurements over a nine year period. The suite of more than thirty atmospheric trace gases profiled includes CO2, O3, N2O, CH4, H2O, NO, NO2, HNO3, HCl, HF, ClONO2, CCl3F, CCl2F2, CHF2Cl, and N2O5. The analysis method has been revised throughout the mission years culminating in the 'version 2' data set. The spectroscopic error analysis is described in the context of supporting the precision estimates reported with the profiles; in addition, systematic uncertainties assessed from the quality of the spectroscopic database are described and tabulated for comparisons with other experiments.

  4. Titan Ice and Dust Experiment (TIDE): Detection and Analysis of Compounds of Interest to Astrobiology in the Lower Atmosphere and Surface of Titan

    NASA Technical Reports Server (NTRS)

    Kojiro, Daniel R.; Holland Paul M.; Stimac, Robert M.; Kaye, William J.; Takeruchi, Noreshige

    2004-01-01

    The Titan Orbiter Aerorover Mission (TOAM) is a proposed concept for the Solar System Exploration Visions Mission, Titan Explorer, a follow-on to the Cassini-Huygens mission. TOAM would use a Titan polar orbiter and a lighter-than-air aerorover to investigate the surface and atmosphere of Titan. Astrobiology issues will be addressed though TOAM investigations including, for example: Distribution and composition of organics (atmospheric, aerosol, surface); Organic chemical processes, their chemical context and energy sources; and Seasonal variations and interactions of the atmosphere and surface. The TIDE instrument will perform in-situ analyses to obtain comprehensive and sensitive molecular and elemental assays of volatile organics in the atmosphere, oceans and surface. TIDE chemical analyses are conducted by a Gas Chromatograph-Ion Mobility Spectrometer (GC-IMS). This TIDE GC-IMS was a component of the mini-Cometary Ice and Dust Experiment (mini-CIDEX) developed for the chemical analysis of a cometary environment. Both the GC and helium IMS of mini-CIDEX have been further developed to better meet the analytical and operational requirements of the TOAM. application. A Micro-ElectroMechanical System (MEMS) GC and Mini-Cell helium IMS are under development to replace their respective mini-CIDEX components, providing similar or advanced analytical capabilities.

  5. Atmospheric Nitrogen Fluorescence Yield

    NASA Technical Reports Server (NTRS)

    Adams, J. H., Jr.; Christl, M. J.; Fountain, W. F.; Gregory, J. C.; Martens, K. U.; Sokolsky, Pierre; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Several existing and planned experiments estimate the energies of ultra-high energy cosmic rays from air showers using the atmospheric nitrogen fluorescence. The nitrogen fluorescence yield from air shower electrons depends on the atmospheric composition. We will discuss the uncertainties in the fluorescence yield form electrons in the real atmosphere and describe a concept for a small balloon payload to measure the atmospheric fluorescence yield as a function of attitude.

  6. Assessing atmospheric nitrogen deposition to natural and semi-natural ecosystems - Experience from Danish studies using the DAMOS

    NASA Astrophysics Data System (ADS)

    Hertel, Ole; Geels, Camilla; Frohn, Lise Marie; Ellermann, Thomas; Skjøth, Carsten Ambelas; Løfstrøm, Per; Christensen, Jesper H.; Andersen, Helle Vibeke; Peel, Robert George

    2013-02-01

    Local agricultural emissions contribute significantly to the atmospheric reactive nitrogen loads of Danish terrestrial ecosystems. In the vicinity of the sources this may be up to 6-8 kg N ha-1 yr-1 depending on location and ecosystem type. This contribution arises from dry deposition of gas phase ammonia derived from local livestock production. Long-range transport, however, often constitutes the largest contribution to the overall atmospheric terrestrial reactive nitrogen loadings in Denmark. This is often in the range 10-15 kg N ha-1 yr-1 and consists mainly of aerosol phase nitrate and ammonium (reaction products of nitrogen oxides and ammonia), but also dry deposition of other reactive nitrogen compounds (mainly nitrogen oxides in the form of gas phase nitric acid and nitrogen dioxide). In Denmark's environmental management of the sensitive terrestrial ecosystems modelling tools are required that account for both the local and the long-range transported contributions. This motivated development of the Danish Ammonia MOdelling System (DAMOS) that has been successfully applied to the assessment of atmospheric nitrogen loadings to sensitive Danish ecosystems. We present here three different examples of such assessments. Our results show that ecosystems located in Western Denmark (Case 1) receive the highest loads of atmospheric nitrogen depositions which generally exceed the critical load. This part of the country has the highest livestock density. In the Eastern part of the country, the atmospheric loadings are often below or close to the lower end of the interval for critical load values. These lower loads in Eastern Denmark (Case 2) are due to lower density of agricultural activities, as well as, lower precipitation rates, which leads to less wet deposition of reactive nitrogen. In general there is a gradient in atmospheric deposition over the country, with the highest depositions in the South-Western part of Denmark (Case 3) due to long-range transport

  7. Mariner 9 S-band Martian occultation experiment - Initial results on the atmosphere and topography of Mars.

    NASA Technical Reports Server (NTRS)

    Kliore, A. J.; Cain, D. L.; Fjeldbo, G.; Seidel, B. L.; Rasool, S. I.

    1972-01-01

    A preliminary analysis of 15 radio occultation measurements taken on the day side of Mars between 40 deg S and 33 deg S has revealed that the temperature in the lower 15 to 20 km of the atmosphere of Mars is essentially isothermal and warmer than expected. This result, which is also confirmed by the increased altitude of the ionization peak of the ionosphere, can possibly be caused by the absorption of solar radiation by fine particles of dust suspended in the lower atmosphere. The floor of the classical bright area of Hellas was found to be about 6 km below its western rim and 4 km below the mean radius of Mars at that latitude.

  8. Using Atmospheric Dispersion Theory to Inform the Design of a Short-lived Radioactive Particle Release Experiment

    SciTech Connect

    Rishel, Jeremy P.; Keillor, Martin E.; Arrigo, Leah M.; Baciak, James E.; Detwiler, Rebecca S.; Kernan, Warnick J.; Kirkham, Randy R.; Milbrath, Brian D.; Seifert, Allen; Seifert, Carolyn E.; Smart, John E.

    2016-01-01

    Atmospheric dispersion theory can be used to predict ground deposition of particulates downwind of a radionuclide release. This paper utilizes standard formulations found in Gaussian plume models to inform the design of an experimental release of short-lived radioactive particles into the atmosphere. Specifically, a source depletion algorithm is used to determine the optimum particle size and release height that maximizes the near-field deposition while minimizing the both the required source activity and the fraction of activity lost to long-distance transport. The purpose of the release is to provide a realistic deposition pattern that might be observed downwind of a small-scale vent from an underground nuclear explosion. The deposition field will be used, in part, to investigate several techniques of gamma radiation survey and spectrometry that could be utilized by an On-Site Inspection team under the verification regime of the Comprehensive Nuclear-Test-Ban Treaty.

  9. Composition and thermal profiles of the Jovian upper atmosphere determined by the Voyager ultraviolet stellar occultation experiment

    NASA Technical Reports Server (NTRS)

    Festou, M. C.; Atreya, S. K.; Donahue, T. M.; Sandel, B. R.; Shemansky, D. E.; Broadfoot, A. L.

    1981-01-01

    During the occultation of the star Regulus (B7 type) by Jupiter as seen from the Voyager 2 spacecraft on July 9, 1979, two absorbing regions were detected. Between 911 and 1200 A, H2 was absorbing over a 600 km altitude range. Above 1300 A, the rapid increase of the absorption by the hydrocarbons was observed over an altitude interval of approximately 100 km with a height resolution of 3 km. The analysis of these absorption features has provided the height profiles of molecular hydrogen, methane, ethane, and acetylene, as well as the thermal profile in the upper atmosphere of Jupiter. Combining the Voyager ultraviolet spectrometer results with other data, such as those obtained by the Voyager infrared and radioscience instruments, has yielded a comprehensive model of the composition and structure of the atmosphere of Jupiter.

  10. Solar radiation absorption in the atmosphere due to water and ice clouds: Sensitivity experiments with plane-parallel clouds

    SciTech Connect

    Gautier, C.

    1995-09-01

    One cloud radiation issue that has been troublesome for several decades is the absorption of solar radiation by clouds. Many hypotheses have been proposed to explain the discrepancies between observations and modeling results. A good review of these often-competing hypotheses has been provided by Stephens and Tsay. They characterize the available hypotheses as failing into three categories: (1) those linked to cloud microphysical and consequent optical properties; (2) those linked to the geometry and heterogeneity of clouds; and (3) those linked to atmospheric absorption.Current modeling practice is seriously inconsistent with new observational inferences concerning absorption of solar radiation in the atmosphere. The author and her colleagues contend that an emphasis on R may, therefore, not be the optimal way of addressing the cloud solar absorption issue. 4 refs., 1 fig.

  11. ARM tropical pacific experiment (ATPEX): Role of cloud, water vapor and convection feedbacks in the coupled ocean/atmosphere system

    SciTech Connect

    Ramanathan, V.; Barnett, T.P.

    1992-03-05

    We have initiated studies that include radiation model validation, improved treatment of the three-dimensional structure of cloud-radiation interactions, and sensitivity runs that will unravel the role of cloud-convection-radiation interactions in the Pacific Sear Surface Temperatures and the overlying Walker and Hadley circulation. The research program is divided into three phases: (1) radiation, (2) cloud parameterization issues; (3) feedback and ocean-atmosphere interactions.

  12. Impact of Arctic sea ice loss on large-scale atmospheric circulation based on fully-coupled sensitivity experiments

    NASA Astrophysics Data System (ADS)

    Oudar, Thomas; Sanchez, Emilia; Terray, Laurent; Chauvin, Fabrice

    2016-04-01

    Arctic sea ice decline in the recent decades has been reported in observational studies. Modeling studies have confirmed that this downward trend in Arctic sea ice is mainly caused by increasing Greenhouse Gases (GHGs) concentrations into the atmosphere. The IPCC-AR5 report concluded that Arctic sea ice will continue to decrease and is projected to disappear in the middle of the 21st century, yielding to a ice-free region during boreal summer season. Arctic sea ice loss is expected to strongly impact the climate system. Recently, the climate community has conducted a number of studies to evaluate and understand the Arctic sea ice loss implications on climate. While some studies have shown that Arctic sea ice decline can significantly affect the large-scale atmospheric dynamics at high and mid-latitudes of the Northern Hemisphere, by altering the storm-tracks, the jet stream (position and strength) and the planetary waves, large uncertainties remain due to a low signal-to-noise ratio and experimental protocol differences leading to a large inter-model spread. In this work, we investigate the respective roles of Arctic sea ice loss and GHGs increase on the atmospheric dynamics by means of an idealized experimental set-up that uses the coupled model CNRM-CM5. The experimental set-up, based on a flux correction technique, will allow separating the contributions of Arctic sea ice loss from the GHGs increasing. We will focus mainly on the atmospheric circulation response in the Northern Hemisphere and on the associated synoptic variability, represented by the storm-tracks. We show that Arctic sea ice loss is responsible for an equatorward shift of the northern hemisphere jet, which is opposed to the GHGs effect. Finally we show that these shifts are consistent with the storm-tracks response.

  13. Pulling Results Out of Thin Air: Four Years of Ozone and Greenhouse Gas Measurements by the Alpha Jet Atmospheric Experiment (AJAX)

    NASA Technical Reports Server (NTRS)

    Yates, Emma

    2015-01-01

    The Alpha Jet Atmospheric eXperiment (AJAX) has been measuring atmospheric ozone, carbon dioxide, methane and meteorological parameters from near the surface to 8000 m since January 2011. The main goals are to study photochemical ozone production and the impacts of extreme events on western US air quality, provide data to support satellite observations and aid in the quantification of emission sources e.g. wildfires, urban outflow, diary and oil and gas. The aircraft is based at Moffett Field and flies multiple times a month to sample vertical profiles at selected sites in California and Nevada, providing long-term data records at these sites. AJAX is also uniquely positioned to launch with short notice sampling flights in rapid response to extreme events e.g. the 2013 Yosemite Rim fire. This talk will focus on the impacts of vertical transport on surface air quality, and investigation of emission sources from diaries and wildfires.

  14. Detecting surface roughness effects on the atmospheric boundary layer via AIRSAR data: A field experiment in Death Valley, California

    NASA Technical Reports Server (NTRS)

    Blumberg, Dan G.; Greeley, Ronald

    1992-01-01

    The part of the troposphere influenced by the surface of the earth is termed the atmospheric boundary layer. Flow within this layer is influenced by the roughness of the surface; rougher surfaces induce more turbulence than smoother surfaces and, hence, higher atmospheric transfer rates across the surface. Roughness elements also shield erodible particles, thus decreasing the transport of windblown particles. Therefore, the aerodynamic roughness length (z(sub 0)) is an important parameter in aeolian and atmospheric boundary layer processes as it describes the aerodynamic properties of the underlying surface. z(sub 0) is assumed to be independent of wind velocity or height, and dependent only on the surface topography. It is determined using in situ measurements of the wind speed distribution as a function of height. For dry, unvegetated soils the intensity of the radar backscatter (sigma(sup 0)) is affected primarily by surface roughness at a scale comparable with the radar wavelength. Thus, both wind and radar respond to surface roughness variations on a scale of a few meters or less. Greeley showed the existence of a correlation between z(sub 0) and sigma(sup 0). This correlation was based on measurements over lava flows, alluvial fans, and playas in the southwest deserts of the United States. It is shown that the two parameters behave similarly also when there are small changes over a relatively homogeneous surface.

  15. Martian atmosphere modeling between 0.4 and 3.5 microns - Comparison of theory and experiment

    NASA Technical Reports Server (NTRS)

    Egan, W. G.; Fischbein, W. L.; Hilgeman, T.; Smith, L. L.

    1978-01-01

    A model of the lower atmosphere of Mars has been constructed that combines aerosol absorption and scattering with a line-by-line analysis of CO2 and H2O in a multilayer radiative transfer program. Aerosol composition previously inferred from the NASA Lear Jet Observatory data was used to measure the optical complex indices of refraction of appropriate Martian analogs from 0.4 to 2.5 microns. The aerosol vertical particle density scale was deduced using the Viking camera observations of the soil and sky intensities between 0.4 and 1.0 microns in comparison with those modeled using a multilayer Mie scattering program. A comparison of observed Mars atmospheric absorptions was made with those obtained using Lorentz, Voigt, and Doppler line profiles in a multilayer model of the CO2 and H2O. The Voigt line profile of CO2 absorption at approximately 4976 kaysers was then combined in a multilayer aerosol model of the Martian atmosphere. An evaluation of the effect on the line shape was made using several aerosol loadings.

  16. Getting the Lead Out of Bermuda; The Legacy of a Forty Year Record in the North Atlantic Using a Transient Experiment in the Atmosphere and Water

    NASA Astrophysics Data System (ADS)

    Church, T. M.; Alleman, L. Y.; Veron, A. J. J.; Boyle, E. A.; Zurbrick, C.; Patterson, C. C.; Flegal, A. R., Jr.

    2015-12-01

    Some forty years ago, Schaule and Patterson established the first accurate profile of lead in waters off Bermuda. In evidence was a massive environmental insult from lead emissions being carried seaward by the atmosphere over the Sargasso Sea. Further documentation was possible using contiguous time series in the atmosphere on Bermuda, surface sea water nearby and recorded in local corals. Lead had then an overwhelming source from the combustion of gasoline, primarily in the USA and secondarily in Europe. These were carried to Bermuda on seasonally alternating temperate and trade winds from the west and east, respectively. The anthropogenic sources were well distinguished based on the unique radiogenic nature of stable lead isotopes in the gasoline being used by these countries. Subsequently, decreasing use in the west (USA) followed by that in the east (Europe) was isotopically evident. As such, the two signatures were subjected to transient mixing in the atmosphere and subsequently with depth in ocean. A transient experiment uses data during 1996-1998, a period of transition in leaded gasoline use in the USA and Europe. Here are complimentary records of lead concentration and stable isotopes in atmospheric deposition and surface waters. The results allow an isotopic mass balance, indicating much of the lead in Bermuda surface water at that time may not have been deposited locally. As such, it may be presumed to reflect easterly advection of some lead at the surface under limited scavenging via the prevailing subtropical gyre circulation. These annual circulation periods are consistent with both physical data and another lead isotopic mass balance in the east. Going forward, Bermuda time series of trace elements and isotopes such as lead could continue to record climatological (e.g. NAO) transients in atmospheric scavenging, potential impact on surface ecosystems, and changes in mixing into deeper waters of the Sargasso Sea and points further afield.

  17. Functional activity of plasmid DNA after entry into the atmosphere of earth investigated by a new biomarker stability assay for ballistic spaceflight experiments.

    PubMed

    Thiel, Cora S; Tauber, Svantje; Schütte, Andreas; Schmitz, Burkhard; Nuesse, Harald; Moeller, Ralf; Ullrich, Oliver

    2014-01-01

    Sounding rockets represent an excellent platform for testing the influence of space conditions during the passage of Earth's atmosphere and re-entry on biological, physical and chemical experiments for astrobiological purposes. We designed a robust functionality biomarker assay to analyze the biological effects of suborbital spaceflights prevailing during ballistic rocket flights. During the TEXUS-49 rocket mission in March 2011, artificial plasmid DNA carrying a fluorescent marker (enhanced green fluorescent protein: EGFP) and an antibiotic resistance cassette (kanamycin/neomycin) was attached on different positions of rocket exterior; (i) circular every 90 degree on the outer surface concentrical of the payload, (ii) in the grooves of screw heads located in between the surface application sites, and (iii) on the surface of the bottom side of the payload. Temperature measurements showed two major peaks at 118 and 130 °C during the 780 seconds lasting flight on the inside of the recovery module, while outer gas temperatures of more than 1000 °C were estimated on the sample application locations. Directly after retrieval and return transport of the payload, the plasmid DNA samples were recovered. Subsequent analyses showed that DNA could be recovered from all application sites with a maximum of 53% in the grooves of the screw heads. We could further show that up to 35% of DNA retained its full biological function, i.e., mediating antibiotic resistance in bacteria and fluorescent marker expression in eukaryotic cells. These experiments show that our plasmid DNA biomarker assay is suitable to characterize the environmental conditions affecting DNA during an atmospheric transit and the re-entry and constitute the first report of the stability of DNA during hypervelocity atmospheric transit indicating that sounding rocket flights can be used to model the high-speed atmospheric entry of organics-laden artificial meteorites.

  18. Functional Activity of Plasmid DNA after Entry into the Atmosphere of Earth Investigated by a New Biomarker Stability Assay for Ballistic Spaceflight Experiments

    PubMed Central

    Thiel, Cora S.; Tauber, Svantje; Schütte, Andreas; Schmitz, Burkhard; Nuesse, Harald; Moeller, Ralf; Ullrich, Oliver

    2014-01-01

    Sounding rockets represent an excellent platform for testing the influence of space conditions during the passage of Earth's atmosphere and re-entry on biological, physical and chemical experiments for astrobiological purposes. We designed a robust functionality biomarker assay to analyze the biological effects of suborbital spaceflights prevailing during ballistic rocket flights. During the TEXUS-49 rocket mission in March 2011, artificial plasmid DNA carrying a fluorescent marker (enhanced green fluorescent protein: EGFP) and an antibiotic resistance cassette (kanamycin/neomycin) was attached on different positions of rocket exterior; (i) circular every 90 degree on the outer surface concentrical of the payload, (ii) in the grooves of screw heads located in between the surface application sites, and (iii) on the surface of the bottom side of the payload. Temperature measurements showed two major peaks at 118 and 130°C during the 780 seconds lasting flight on the inside of the recovery module, while outer gas temperatures of more than 1000°C were estimated on the sample application locations. Directly after retrieval and return transport of the payload, the plasmid DNA samples were recovered. Subsequent analyses showed that DNA could be recovered from all application sites with a maximum of 53% in the grooves of the screw heads. We could further show that up to 35% of DNA retained its full biological function, i.e., mediating antibiotic resistance in bacteria and fluorescent marker expression in eukariotic cells. These experiments show that our plasmid DNA biomarker assay is suitable to characterize the environmental conditions affecting DNA during an atmospheric transit and the re-entry and constitute the first report of the stability of DNA during hypervelocity atmospheric transit indicating that sounding rocket flights can be used to model the high-speed atmospheric entry of organics-laden artificial meteorites. PMID:25426925

  19. Understanding Titan's Atmospheric Isotope Inventory through Laboratory Photolysis Experiments using Vacuum Ultraviolet Photons from Advanced Light Source Synchrotron

    NASA Astrophysics Data System (ADS)

    Chakraborty, S.

    2015-12-01

    Titan, Saturn's planet-like moon with a thick atmosphere consists mainly of N2 (98.4 %) and CH4 (1.4%). It is debated whether the N2 is primordial, or the NH3, which later converted to N2 by physic-chemical processes and, if NH3 is primordial, what is the source of that material: Saturnian-subnebula or the comets? N2 is enriched in 15N (14N/15N = 160 compared to 272 for Earth) and in geochemical terminology, d15Nair = 700 ‰ (parts per thousand with respect to ambient air). On the same scale the solar wind and Jupiter's atmosphere are ~ -400 ‰ (depleted in 15N). The comets (NH3 and HCN) and insoluble organic matter in meteorites are also enriched in 15N in the range up to a few thousand ‰. On the contrary, the carbon isotopic ratio in CH4 in Titan is similar to the other solar system bodies (12C/13C~ 89). We have performed extensive low temperature (80 K) photodissociation of N2 and CO (in presence of H2) at VUV wavelengths to measure the isotopic fractionation in the products. The integrated instantaneous fractionation in the product NH3 is about 1000 ‰ over the N2 dissociation regime (80-100 nm), which arise due to quantum mechanical selection rules. CO2 and CH4, the products of CO photodissociation, show contradictory results for two elements. While product O (trapped in CO2) is enriched by few thousand ‰, there is no significant C isotopic enrichment in CH4. These laboratory measurements along with the measurements by Cassini-Huygens spacecraft constrain the origin of volatiles in Titan's atmosphere and indicate that Titan accreted comet-like NH3 and CH4, which are the 1st generation photolysis products (of the remaining materials after the formation of gas giants) in the solar nebula. Later, NH3 converted to N2 in a bulk fashion (within Titan) and retained mostly identical isotopic composition. 15N enrichment measured in HCN in the present day atmosphere (d15Nair > 1500 ‰), is possibly from the 2nd generation N2 photolysis in Titan's modern

  20. Mitigation of Atmospheric Delay in SAR Absolute Ranging Using Global Numerical Weather Prediction Data: Corner Reflector Experiments at 3 Different Test Sites

    NASA Astrophysics Data System (ADS)

    Cong, Xiaoying; Balss, Ulrich; Eineder, Michael

    2015-04-01

    The atmospheric delay due to vertical stratification, the so-called stratified atmospheric delay, has a great impact on both interferometric and absolute range measurements. In our current researches [1][2][3], centimeter-range accuracy has been proven based on Corner Reflector (CR) based measurements by applying atmospheric delay correction using the Zenith Path Delay (ZPD) corrections derived from nearby Global Positioning System (GPS) stations. For a global usage, an effective method has been introduced to estimate the stratified delay based on global 4-dimensional Numerical Weather Prediction (NWP) products: the direct integration method [4][5]. Two products, ERA-Interim and operational data, provided by European Centre for Medium-Range Weather Forecast (ECMWF) are used to integrate the stratified delay. In order to access the integration accuracy, a validation approach is investigated based on ZPD derived from six permanent GPS stations located in different meteorological conditions. Range accuracy at centimeter level is demonstrated using both ECMWF products. Further experiments have been carried out in order to determine the best interpolation method by analyzing the temporal and spatial correlation of atmospheric delay using both ECMWF and GPS ZPD. Finally, the integrated atmospheric delays in slant direction (Slant Path Delay, SPD) have been applied instead of the GPS ZPD for CR experiments at three different test sites with more than 200 TerraSAR-X High Resolution SpotLight (HRSL) images. The delay accuracy is around 1-3 cm depending on the location of test site due to the local water vapor variation and the acquisition time/date. [1] Eineder M., Minet C., Steigenberger P., et al. Imaging geodesy - Toward centimeter-level ranging accuracy with TerraSAR-X. Geoscience and Remote Sensing, IEEE Transactions on, 2011, 49(2): 661-671. [2] Balss U., Gisinger C., Cong X. Y., et al. Precise Measurements on the Absolute Localization Accuracy of TerraSAR-X on the

  1. High-resolution atmospheric inversion of urban CO2 emissions during the dormant season of the Indianapolis Flux Experiment (INFLUX)

    NASA Astrophysics Data System (ADS)

    Lauvaux, Thomas; Miles, Natasha L.; Deng, Aijun; Richardson, Scott J.; Cambaliza, Maria O.; Davis, Kenneth J.; Gaudet, Brian; Gurney, Kevin R.; Huang, Jianhua; O'Keefe, Darragh; Song, Yang; Karion, Anna; Oda, Tomohiro; Patarasuk, Risa; Razlivanov, Igor; Sarmiento, Daniel; Shepson, Paul; Sweeney, Colm; Turnbull, Jocelyn; Wu, Kai

    2016-05-01

    Based on a uniquely dense network of surface towers measuring continuously the atmospheric concentrations of greenhouse gases (GHGs), we developed the first comprehensive monitoring systems of CO2 emissions at high resolution over the city of Indianapolis. The urban inversion evaluated over the 2012-2013 dormant season showed a statistically significant increase of about 20% (from 4.5 to 5.7 MtC ± 0.23 MtC) compared to the Hestia CO2 emission estimate, a state-of-the-art building-level emission product. Spatial structures in prior emission errors, mostly undetermined, appeared to affect the spatial pattern in the inverse solution and the total carbon budget over the entire area by up to 15%, while the inverse solution remains fairly insensitive to the CO2 boundary inflow and to the different prior emissions (i.e., ODIAC). Preceding the surface emission optimization, we improved the atmospheric simulations using a meteorological data assimilation system also informing our Bayesian inversion system through updated observations error variances. Finally, we estimated the uncertainties associated with undetermined parameters using an ensemble of inversions. The total CO2 emissions based on the ensemble mean and quartiles (5.26-5.91 MtC) were statistically different compared to the prior total emissions (4.1 to 4.5 MtC). Considering the relatively small sensitivity to the different parameters, we conclude that atmospheric inversions are potentially able to constrain the carbon budget of the city, assuming sufficient data to measure the inflow of GHG over the city, but additional information on prior emission error structures are required to determine the spatial structures of urban emissions at high resolution.

  2. Climate sensitivity due to increased CO2: experiments with a coupled atmosphere and ocean general circulation model

    NASA Astrophysics Data System (ADS)

    Washington, Warren M.; Meehl, Gerald A.

    1989-06-01

    A version of the National Center for Atmospheric Research community climate model — a global, spectral (R15) general circulation model — is coupled to a coarse-grid (5° latitude-] longitude, four-layer) ocean general circulation model to study the response of the climate system to increases of atmospheric carbon dioxide (CO2). Three simulations are run: one with an instantaneous doubling of atmospheric CO2 (from 330 to 660 ppm), another with the CO2 concentration starting at 330 ppm and increasing linearly at a rate of 1% per year, and a third with CO2 held constant at 330 pm. Results at the end of 30 years of simulation indicate a globally averaged surface air temperature increase of 1.6° C for the instantaneous doubling case and 0.7°C for the transient forcing case. Inherent characteristics of the coarse-grid ocean model flow sea-surface temperatures (SSTs) in the tropics and higher-than-observed SSTs and reduced sea-ice extent at higher latitudes] produce lower sensitivity in this model after 30 years than in earlier simulations with the same atmosphere coupled to a 50-m, slab-ocean mixed layer. Within the limitations of the simulated meridional overturning, the thermohaline circulation weakens in the coupled model with doubled CO2 as the high-latitude ocean-surface layer warms and freshens and westerly wind stress is decreased. In the transient forcing case with slowly increasing CO2 (30% increase after 30 years), the zonal mean warming of the ocean is most evident in the surface layer near 30° 50° S. Geographical plots of surface air temperature change in the transient case show patterns of regional climate anomalies that differ from those in the instantaneous CO2 doubling case, particularly in the North Atlantic and northern European regions. This suggests that differences in CO2 forcing in the climate system are important in CO2 response in regard to time-dependent climate anomaly regimes. This confirms earlier studies with simple climate models

  3. The Sensitivity of Atmospheric Dispersion Calculations in Near-field Applications: Modeling of the Full Scale RDD Experiments with Operational Models in Canada, Part I.

    PubMed

    Lebel, Luke; Bourgouin, Pierre; Chouhan, Sohan; Ek, Nils; Korolevych, Volodymyr; Malo, Alain; Bensimon, Dov; Erhardt, Lorne

    2016-05-01

    Three radiological dispersal devices were detonated in 2012 under controlled conditions at Defence Research and Development Canada's Experimental Proving Grounds in Suffield, Alberta. Each device comprised a 35-GBq source of (140)La. The dataset obtained is used in this study to assess the MLCD, ADDAM, and RIMPUFF atmospheric dispersion models. As part one of a two-part study, this paper focuses on examining the capabilities of the above three models and evaluating how well their predictions of air concentration and ground deposition match observations from the full-scale RDD experiments.

  4. Changes in mass and energy transfer between the canopy and the atmosphere: model development and testing with a free-air CO2 enrichment (FACE) experiment

    NASA Astrophysics Data System (ADS)

    Manunta, Paolo; Grant, Robert F.; Feng, Yongshen; Kimball, Bruce A.; Pinter, Paul J.; La Morte, Robert L.; Hunsaker, Douglas J.; Wall, D.

    2002-02-01

    The rationale for this study is found in the probable higher temperatures and changes in rainfall patterns that are expected in the future as a result of increasing levels of CO2 in the atmosphere. In particular, higher air temperatures may cause an increase in evapotranspiration demand while a reduction in rainfall could increase the severity and duration of drought in arid and semi-arid regions. Representation of the water transfer scheme includes water uptake by roots and the interaction between evapotranspiration and CO2 enrichment. The predicted response of a spring wheat ( Triticum aestivum L. cv. Yecora rojo) canopy in terms of energy exchange processes to elevated atmospheric CO2 level was tested against measurements collected at the FACE (Free Air Enrichment Experiment) site in 1994. Simulated and measured canopy conductances were reduced by about 30% under elevated [CO2] under optimum conditions of water supply. Reductions in latent heat fluxes under elevated instead of ambient [CO2] caused reductions in both simulated and measured seasonal water use of 6% under optimum and 2% under suboptimum irrigation. The soil-plant-atmosphere water transfer scheme proposed here offers several advances in the simulation of land surface interactions. First, the stomatal resistance model minimizes assumptions in existing land surface schemes about the effects of interactions among environmental conditions (radiation, temperature, CO2) upon stomatal behavior. These interactions are resolved in the calculation of CO2 in which processes are already well understood.

  5. [Pierre Bourdieu and health: a sociological analysis of Actes de la Recherche en Sciences Sociales].

    PubMed

    Montagner, Miguel Angelo

    2008-07-01

    This study aimed to highlight, illustrate, describe, and comment on the presence of the health category in the work of Pierre Bourdieu, by underlining the themes traditionally related to the sociology of the body. After a systematic analysis of his work in the sociology of medicine and health, the article also addresses the main vehicle for his line of thought, namely Actes de la Recherche en Sciences Sociales, viewed here as the prime channel for most of the research taking Bourdieu's "genetic structuralism" as the main theoretical reference. We analyze the articles published from 1975 to 2001, from the thematic and theoretical/conceptual perspective, by comparing the changes appearing in this journal in opposition to the model previously adopted by the Revue Française de Sociologie.

  6. A la recherches d'autres mondes - les exoplanètes

    NASA Astrophysics Data System (ADS)

    Nazé, Yaël

    2013-10-01

    Habiter ailleurs que sur Terre, en dehors du système solaire, est-ce vraiment possible ? Est-ce que la vie existe en dehors du Système solaire et comment la chercher ? Ces questions sont celles que les hommes et les femmes se posent et celles qu'ils se sont posées de tout temps. Les scientifiques n'échappent pas à cette règle et nous vivons à une époque fascinante où cette recherche évolue extrêmement vite : ils ont découvert d'autres lieux potentiellement habitables ou habités, les exoplanètes, des planètes tournant autour d'autres soleils dans l'univers. À ce jour, plus de 900 exoplanètes ont ainsi été détectées

  7. Atmospheric science

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Ackerman, Thomas; Clarke, Antony; Goodman, Jindra; Levin, Zev; Tomasko, Martin; Toon, O. Brian; Whitten, Robert

    1987-01-01

    The following types of experiments for a proposed Space Station Microgravity Particle Research Facility are described: (1) growth of liquid water drop populations; (2) coalescence; (3) drop breakup; (4) breakup of freezing drops; (5) ice nucleation for large aerosols or bacteria; (6) scavenging of gases, for example, SO2 oxidation; (7) phoretic forces, i.e., thermophoresis versus diffusiophoresis; (8) Rayleigh bursting of drops; (9) charge separation due to collisions of rimed and unrimed ice; (10) charged drop dynamics; (11) growth of particles in other planetary atmospheres; and (12) freezing and liquid-liquid evaporation. The required capabilities and desired hardware for the facility are detailed.

  8. Atmospheric Test Models and Numerical Experiments for the Simulation of the Global Distributions of Weather Data Transponders III. Horizontal Distributions

    SciTech Connect

    Molenkamp, C.R.; Grossman, A.

    1999-12-20

    A network of small balloon-borne transponders which gather very high resolution wind and temperature data for use by modern numerical weather predication models has been proposed to improve the reliability of long-range weather forecasts. The global distribution of an array of such transponders is simulated using LLNL's atmospheric parcel transport model (GRANTOUR) with winds supplied by two different general circulation models. An initial study used winds from CCM3 with a horizontal resolution of about 3 degrees in latitude and longitude, and a second study used winds from NOGAPS with a 0.75 degree horizontal resolution. Results from both simulations show that reasonable global coverage can be attained by releasing balloons from an appropriate set of launch sites.

  9. A Year-Long Research Experience Program in Solar and Atmospheric Physics at the Queensborough Community College of the City University of New York (CUNY)

    NASA Astrophysics Data System (ADS)

    Damas, M. C.; Cheung, T. D.; Ngwira, C.; Mohamed, A.; Knipp, D. J.; Johnson, L. P.; Zheng, Y.; Paglione, T.

    2015-12-01

    The Queensborough Community College (QCC) of the City University of New York (CUNY), a Hispanic and minority-serving institution, is the recipient of a 2-year NSF EAGER (Early Concept Grants for Exploratory Research) grant to design and implement a high-impact practice integrated research and education program in solar and atmospheric physics. Through a strong collaboration with CUNY/City College of New York and NASA Goddard Space Flight Center's Community Coordinated Modeling Center (CCMC), the project engages underrepresented community college students in geosciences-related STEM fields through a year-long research experience with two components: 1) during the academic year, students are enrolled in a course-based introductory research (CURE) where they conduct research on real-world problems; and 2) during the summer, students are placed in research internships at partner institutions. We will present the results of the first year-long research experience, including successes and challenges.

  10. Airborne measurements of black carbon aerosol over the Southeastern U.S. during the Southeast Atmosphere Study (SAS) experiment

    NASA Astrophysics Data System (ADS)

    Markovic, M. Z.; Perring, A. E.; Schwarz, J. P.; Fahey, D. W.; Gao, R.; Watts, L.; Holloway, J.; Graus, M.; Warneke, C.; De Gouw, J. A.; Veres, P. R.; Roberts, J. M.; Middlebrook, A. M.; Welti, A.; Liao, J.

    2013-12-01

    The Southeast Atmosphere Study (SAS) field campaign was a large-scale, collaborative project, which took place in the Southeastern U.S. in June and July of 2013. The goal of the campaign was to investigate the impacts of biogenic and anthropogenic gases and aerosols on the formation of haze and anomalous climate cooling in the region. During SAS, a NOAA Single Particle Soot Photometer (SP2) instrument was utilized onboard NOAA WP-3D research aircraft for measurements of black carbon (BC) aerosol mass and microphysical properties. BC aerosol is emitted into the atmosphere from biomass burning (BB) and incomplete combustion of fossil and biofuel. Hence, BC sources are strongly linked to anthropogenic activity. BC aerosol is currently the second largest anthropogenic climate forcing agent after CO2(g), and its climate impacts, which depend on vertical burden and internal mixing, are not fully understood. In the Southeast, BC aerosol is expected to provide surface area for the condensation of semi-volatile products of VOC oxidation and subsequent formation of secondary organic aerosol (SOA). Hence, BC is expected to impact the haze formation and regional climate. In this work we present an overview of BC measurements during Southeast Nexus (SENEX) study, the NOAA contribution to SAS. Geographical variations in mass mixing ratios, mass size distributions, and mixing state of BC over the Southeast U.S. are discussed. Relationships of BC with carbon monoxide (CO), acetonitrile (ACN) and other trace gases are used to investigate the impacts of urban, BB, natural gas development, and power plant emissions on the distribution and properties of BC aerosol in the region. Among studied urban centers, St. Louis and Atlanta were determined to be the largest source regions of BC. A clear weekend effect in BC mass mixing ratios and microphysical properties was observed in the metropolitan Atlanta region. Compared to BB and urban centers, power plants and natural gas developments

  11. Testing ice microphysics parameterizations in the NCAR Community Atmospheric Model Version 3 using Tropical Warm Pool-International Cloud Experiment data

    SciTech Connect

    Wang, Weiguo; Liu, Xiaohong; Xie, Shaocheng; Boyle, Jim; McFarlane, Sally A.

    2009-07-23

    Here, cloud properties have been simulated with a new double-moment microphysics scheme under the framework of the single-column version of NCAR Community Atmospheric Model version 3 (CAM3). For comparison, the same simulation was made with the standard single-moment microphysics scheme of CAM3. Results from both simulations compared favorably with observations during the Tropical Warm Pool–International Cloud Experiment by the U.S. Department of Energy Atmospheric Radiation Measurement Program in terms of the temporal variation and vertical distribution of cloud fraction and cloud condensate. Major differences between the two simulations are in the magnitude and distribution of ice water content within the mixed-phase cloud during the monsoon period, though the total frozen water (snow plus ice) contents are similar. The ice mass content in the mixed-phase cloud from the new scheme is larger than that from the standard scheme, and ice water content extends 2 km further downward, which is in better agreement with observations. The dependence of the frozen water mass fraction on temperature from the new scheme is also in better agreement with available observations. Outgoing longwave radiation (OLR) at the top of the atmosphere (TOA) from the simulation with the new scheme is, in general, larger than that with the standard scheme, while the surface downward longwave radiation is similar. Sensitivity tests suggest that different treatments of the ice crystal effective radius contribute significantly to the difference in the calculations of TOA OLR, in addition to cloud water path. Numerical experiments show that cloud properties in the new scheme can respond reasonably to changes in the concentration of aerosols and emphasize the importance of correctly simulating aerosol effects in climate models for aerosol-cloud interactions. Further evaluation, especially for ice cloud properties based on in-situ data, is needed.

  12. Testing ice microphysics parameterizations in the NCAR Community Atmospheric Model Version 3 using Tropical Warm Pool-International Cloud Experiment data

    DOE PAGES

    Wang, Weiguo; Liu, Xiaohong; Xie, Shaocheng; ...

    2009-07-23

    Here, cloud properties have been simulated with a new double-moment microphysics scheme under the framework of the single-column version of NCAR Community Atmospheric Model version 3 (CAM3). For comparison, the same simulation was made with the standard single-moment microphysics scheme of CAM3. Results from both simulations compared favorably with observations during the Tropical Warm Pool–International Cloud Experiment by the U.S. Department of Energy Atmospheric Radiation Measurement Program in terms of the temporal variation and vertical distribution of cloud fraction and cloud condensate. Major differences between the two simulations are in the magnitude and distribution of ice water content within themore » mixed-phase cloud during the monsoon period, though the total frozen water (snow plus ice) contents are similar. The ice mass content in the mixed-phase cloud from the new scheme is larger than that from the standard scheme, and ice water content extends 2 km further downward, which is in better agreement with observations. The dependence of the frozen water mass fraction on temperature from the new scheme is also in better agreement with available observations. Outgoing longwave radiation (OLR) at the top of the atmosphere (TOA) from the simulation with the new scheme is, in general, larger than that with the standard scheme, while the surface downward longwave radiation is similar. Sensitivity tests suggest that different treatments of the ice crystal effective radius contribute significantly to the difference in the calculations of TOA OLR, in addition to cloud water path. Numerical experiments show that cloud properties in the new scheme can respond reasonably to changes in the concentration of aerosols and emphasize the importance of correctly simulating aerosol effects in climate models for aerosol-cloud interactions. Further evaluation, especially for ice cloud properties based on in-situ data, is needed.« less

  13. AmazonFACE: Assessing the Effects of Increasing Atmospheric CO2 on the Resilience of the Amazon Forest through Integrative Model-Experiment Research

    NASA Astrophysics Data System (ADS)

    Lapola, D. M.

    2015-12-01

    The existence, magnitude and duration of a supposed "CO2 fertilization" effect in tropical forests remains largely undetermined, despite being suggested for nearly 20 years as a key knowledge gap for understanding the future resilience of Amazonian forests and its impact on the global carbon cycle. Reducing this uncertainty is critical for assessing the future of the Amazon region as well as its vulnerability to climate change. The AmazonFACE (Free-Air CO2 Enrichment) research program is an integrated model-experiment initiative of unprecedented scope in an old-growth Amazon forest near Manaus, Brazil - the first of its kind in tropical forest. The experimental treatment will simulate an atmospheric CO2 concentration [CO2] of the future in order to address the question: "How will rising atmospheric CO2 affect the resilience of the Amazon forest, the biodiversity it harbors, and the ecosystem services it provides, in light of projected climatic changes?" AmazonFACE is divided into three phases: (I) pre-experimental ecological characterization of the research site; (II) pilot experiment comprised of two 30-m diameter plots, with one treatment plot maintained at elevated [CO2] (ambient +200 ppmv), and the other control plot at ambient [CO2]; and (III) a fully-replicated long-term experiment comprised of four pairs of control/treatment FACE plots maintained for 10 years. A team of scientists from Brazil, USA, Australia and Europe will employ state-of-the-art methods to study the forest inside these plots in terms of carbon metabolism and cycling, water use, nutrient cycling, forest community composition, and interactions with environmental stressors. All project phases also encompass ecosystem-modeling activities in a way such that models provide hypothesis to be verified in the experiment, which in turn will feed models to ultimately produce more accurate projections of the environment. Resulting datasets and analyses will be a valuable resource for a broad community

  14. Hydrogen peroxide in the marine atmospheric boundary layer during the Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange experiment in the eastern subtropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Martin, Daniel; Tsivou, Maria; Bonsang, Bernard; Abonnel, Christian; Carsey, Thomas; Springer-Young, Margie; Pszenny, Alex; Suhre, Karsten

    1997-03-01

    Gas phase H2O2 was measured in surface air on the NOAA ship Malcolm Baldrige from June 8 to 27, 1992 (Julian days 160-179), during the Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange experiment in the eastern subtropical North Atlantic region. Average H2O2 mixing ratios observed were 0.63±0.28 ppbv, ranging between detection limit and 1.5 ppbv. For the entire experiment, only weak or no correlation was found between H2O2 mixing ratio and meteorological parameters (pressure, temperature, humidity, or UV radiation flux) as well as with tracers of continental air masses (CO, black carbon, radon). The average daily H2O2 cycle for the entire period exhibits a maximum of 0.8±0.3 ppbv near sunset and a minimum of 0.4±0.2 ppbv 4-5 hours after sunrise. Several clear H2O2 diurnal variations have been observed, from which a first-order removal rate of about 1×10-5 s-1 for H2O2 can be inferred from nighttime measurements. This rate compares well with those deduced from measurements taken at Cape Grim (Tasmania, 41°S) and during the Soviet-American Gas and Aerosol III experiment (equatorial Pacific Ocean).

  15. UV-VIS backscattering measurements on atmospheric particles mixture using polarization lidar coupled with numerical simulations and laboratory experiments

    NASA Astrophysics Data System (ADS)

    Miffre, Alain; Francis, Mirvatte; Anselmo, Christophe; Rairoux, Patrick

    2015-04-01

    As underlined by the latest IPCC report [1], tropospheric aerosols are nowadays recognized as one of the main uncertainties affecting the Earth's climate and human health. This issue is not straightforward due to the complexity of these nanoparticles, which present a wide range of sizes, shapes and chemical composition, which vary as a function of altitude, especially in the troposphere, where strong temperature variations are encountered under different water vapour content (from 10 to 100 % relative humidity). During this oral presentation, I will first present the scientific context of this research. Then, the UV-VIS polarimeter instrument and the subsequent calibration procedure [2] will be presented, allowing quantitative evaluation of particles backscattering coefficients in the atmosphere. In this way, up to three-component particles external mixtures can be partitioned into their spherical and non-spherical components, by coupling UV-VIS depolarization lidar measurements with numerical simulations of backscattering properties specific to non-spherical particles, such as desert dust or sea-salt particles [3], by applying the T-matrix numerical code [4]. This combined methodology is new, as opposed to the traditional approach using the lidar and T-matrix methodologies separately. In complement, recent laboratory findings [5] and field applications [6] will be presented, enhancing the sensitivity of the UV-VIS polarimeter. References [1] IPCC report, Intergovernmental Panel on Climate Change, IPCC, (2013). [2] G. David, A. Miffre, B. Thomas, and P. Rairoux: "Sensitive and accurate dual-wavelength UV-VIS polarization detector for optical remote sensing of tropospheric aerosols," Appl. Phys. B 108, 197-216 (2012). [3] G. David, B. Thomas, T. Nousiainen, A. Miffre and P. Rairoux: "Retrieving simulated volcanic, desert dust, and sea-salt particle properties from two / three-component particle mixtures using UV-VIS polarization Lidar and T-matrix," Atmos. Chem Phys

  16. Atmospheric test models and numerical experiments for the simulation of the global distribution of weather data transponders

    SciTech Connect

    Grossman, A; Molenkamp, C R

    1999-08-25

    A proposal has been made to establish a high density global network of atmospheric micro transponders to record time, temperature, and wind data with time resolution of {le} 1 minute, temperature accuracy of {+-} 1 K, spatial resolution no poorer than {approx}3km horizontally and {approx}0.1km vertically, and 2-D speed accuracy of {le} 1m/s. This data will be used in conjunction with advanced numerical weather prediction models to provide increases in the reliability of long range weather forecasts. Major advances in data collection technology will be required to provide the proposed high-resolution data collection network. Systems studies must be undertaken to determine insertion requirements, spacing, and evolution of the transponder ensemble, which will be used to collect the data. Numerical models which provide realistic global weather pattern simulations must be utilized in order to perform these studies. A global circulation model with a 3{sup o} horizontal resolution has been used for initial simulations of the generation and evolution of transponder distributions. These studies indicate that reasonable global coverage of transponders can be achieved by a launch scenario consisting of the sequential launch of transponders at specified heights from a globally distributed set of launch sites.

  17. Dielectric barrier discharges in helium at atmospheric pressure: experiments and model in the needle-plane geometry

    NASA Astrophysics Data System (ADS)

    Radu, I.; Bartnikas, R.; Wertheimer, M. R.

    2003-06-01

    We present an experimental and numerical modelling study of dielectric barrier discharges in pure, flowing helium at atmospheric pressure, in a 3.0 mm length needle-plane gap. Ultra-high speed imaging and synchronous, real-time dual detection (optical-electrical) diagnostics have been carried out. The high-voltage electrode was a hyperboloidal steel needle with a sharp point of 40 mum radius, while the grounded electrode was covered with 1.6 mm of Al2O3. The surface of the latter was either bare (case 1) or coated with ~20 nm of semiconducting graphite (case 2) or metallic aluminium (case 3), all at floating potential. Axial [z(t)] and radial [r(t)] time-evolutions (leq2 mus) of discharge propagation across the gap were found to depend very strongly upon surface charging or conduction (cases 1-3). A two-dimensional model of the needle-plane discharge, based on coupled solution of the continuity equations for electrons, ions and excited neutral particles and of Poisson's equation, was found to agree very well with the observed [r,z](t) behaviour.

  18. Can agricultural soils effectively remove legacy carbon from the atmosphere? Lessons from Australian long-term soil experiments. (Invited)

    NASA Astrophysics Data System (ADS)

    Sanderman, J.; Baldock, J.; Farquharson, R.

    2009-12-01

    One of the greatest changes that has occurred in soils during the Anthropocene is loss of organic matter due to agriculture. This loss has resulted in both large declines in soil fertility and large emissions of CO2 to the atmosphere. On the billions of hectares in production, humans are likely the only agent that will significantly change this situation. From a theoretical standpoint, any management practice which results in greater carbon return to the soil, increased stabilisation of soil carbon, or a reduction in losses should lead to positive carbon sequestration rates. Indeed, Australian field trial evidence indicates that there was a relative gain in soil carbon between most conventional and improved-management treatments. However, when soil carbon stocks were followed through time, the majority of these same studies indicated that there was an actual decrease in the quantity of carbon stored in the soil even in the improved-management treatments. These seemingly contradictory results suggest that many agricultural soils may still be responding to initial land clearing and that many management improvements are just slowing the loss soil carbon. This reduction in rate of loss of soil carbon represents a real greenhouse gas abatement in the form of avoided emissions. However, the predictive power of results from most agronomic field trials to alternative situations where these management practices have been implemented is questionable without detailed knowledge of the state of the soil carbon in the systems being considered.

  19. Excluded volume and ion-ion correlation effects on the ionic atmosphere around B-DNA: Theory, simulations, and experiments

    NASA Astrophysics Data System (ADS)

    Ovanesyan, Zaven; Medasani, Bharat; Fenley, Marcia O.; Guerrero-García, Guillermo Iván; Olvera de la Cruz, Mónica; Marucho, Marcelo

    2014-12-01

    The ionic atmosphere around a nucleic acid regulates its stability in aqueous salt solutions. One major source of complexity in biological activities involving nucleic acids arises from the strong influence of the surrounding ions and water molecules on their structural and thermodynamic properties. Here, we implement a classical density functional theory for cylindrical polyelectrolytes embedded in aqueous electrolytes containing explicit (neutral hard sphere) water molecules at experimental solvent concentrations. Our approach allows us to include ion correlations as well as solvent and ion excluded volume effects for studying the structural and thermodynamic properties of highly charged cylindrical polyelectrolytes. Several models of size and charge asymmetric mixtures of aqueous electrolytes at physiological concentrations are studied. Our results are in good agreement with Monte Carlo simulations. Our numerical calculations display significant differences in the ion density profiles for the different aqueous electrolyte models studied. However, similar results regarding the excess number of ions adsorbed to the B-DNA molecule are predicted by our theoretical approach for different aqueous electrolyte models. These findings suggest that ion counting experimental data should not be used alone to validate the performance of aqueous DNA-electrolyte models.

  20. NEW ATLAS9 AND MARCS MODEL ATMOSPHERE GRIDS FOR THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT (APOGEE)

    SciTech Connect

    Meszaros, Sz.; Allende Prieto, C.; De Vicente, A.; Edvardsson, B.; Gustafsson, B.; Castelli, F.; Garcia Perez, A. E.; Majewski, S. R.; Plez, B.; Schiavon, R.; Shetrone, M.

    2012-10-01

    We present a new grid of model photospheres for the SDSS-III/APOGEE survey of stellar populations of the Galaxy, calculated using the ATLAS9 and MARCS codes. New opacity distribution functions were generated to calculate ATLAS9 model photospheres. MARCS models were calculated based on opacity sampling techniques. The metallicity ([M/H]) spans from -5 to 1.5 for ATLAS and -2.5 to 0.5 for MARCS models. There are three main differences with respect to previous ATLAS9 model grids: a new corrected H{sub 2}O line list, a wide range of carbon ([C/M]) and {alpha} element [{alpha}/M] variations, and solar reference abundances from Asplund et al. The added range of varying carbon and {alpha}-element abundances also extends the previously calculated MARCS model grids. Altogether, 1980 chemical compositions were used for the ATLAS9 grid and 175 for the MARCS grid. Over 808,000 ATLAS9 models were computed spanning temperatures from 3500 K to 30,000 K and log g from 0 to 5, where larger temperatures only have high gravities. The MARCS models span from 3500 K to 5500 K, and log g from 0 to 5. All model atmospheres are publicly available online.