Science.gov

Sample records for affect atmospheric radiation

  1. Atmospheric radiation

    SciTech Connect

    Harshvardhan, M.R. )

    1991-01-01

    Studies of atmospheric radiative processes are summarized for the period 1987-1990. Topics discussed include radiation modeling; clouds and radiation; radiative effects in dynamics and climate; radiation budget and aerosol effects; and gaseous absorption, particulate scattering and surface reflection. It is concluded that the key developments of the period are a defining of the radiative forcing to the climate system by trace gases and clouds, the recognition that cloud microphysics and morphology need to be incorporated not only into radiation models but also climate models, and the isolation of a few important unsolved theoretical problems in atmospheric radiation.

  2. Atmospheric radiation flight dose rates

    NASA Astrophysics Data System (ADS)

    Tobiska, W. K.

    2015-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has been conducting space weather observations of the atmospheric radiation environment at aviation altitudes that will eventually be transitioned into air traffic management operations. The Automated Radiation Measurements for Aerospace Safety (ARMAS) system and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) both are providing dose rate measurements. Both activities are under the ARMAS goal of providing the "weather" of the radiation environment to improve aircraft crew and passenger safety. Over 5-dozen ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. Flight altitudes now exceed 60,000 ft. and extend above commercial aviation altitudes into the stratosphere. In this presentation we describe recent ARMAS and USEWX results.

  3. Fundamentals of Atmospheric Radiation

    NASA Astrophysics Data System (ADS)

    Bohren, Craig F.; Clothiaux, Eugene E.

    2006-02-01

    This textbook fills a gap in the literature for teaching material suitable for students of atmospheric science and courses on atmospheric radiation. It covers the fundamentals of emission, absorption, and scattering of electromagnetic radiation from ultraviolet to infrared and beyond. Much of the book applies to planetary atmosphere. The authors are physicists and teach at the largest meteorology department of the US at Penn State. Craig T. Bohren has taught the atmospheric radiation course there for the past 20 years with no book. Eugene Clothiaux has taken over and added to the course notes. Problems given in the text come from students, colleagues, and correspondents. The design of the figures especially for this book is meant to ease comprehension. Discussions have a graded approach with a thorough treatment of subjects, such as single scattering by particles, at different levels of complexity. The discussion of the multiple scattering theory begins with piles of plates. This simple theory introduces concepts in more advanced theories, i.e. optical thickness, single-scattering albedo, asymmetry parameter. The more complicated theory, the two-stream theory, then takes the reader beyond the pile-of-plates theory. Ideal for advanced undergraduate and graduate students of atmospheric science.

  4. Atmospheric propagation of THz radiation.

    SciTech Connect

    Wanke, Michael Clement; Mangan, Michael A.; Foltynowicz, Robert J.

    2005-11-01

    In this investigation, we conduct a literature study of the best experimental and theoretical data available for thin and thick atmospheres on THz radiation propagation from 0.1 to 10 THz. We determined that for thick atmospheres no data exists beyond 450 GHz. For thin atmospheres data exists from 0.35 to 1.2 THz. We were successful in using FASE code with the HITRAN database to simulate the THz transmission spectrum for Mauna Kea from 0.1 to 2 THz. Lastly, we successfully measured the THz transmission spectra of laboratory atmospheres at relative humidities of 18 and 27%. In general, we found that an increase in the water content of the atmosphere led to a decrease in the THz transmission. We identified two potential windows in an Albuquerque atmosphere for THz propagation which were the regions from 1.2 to 1.4 THz and 1.4 to 1.6 THz.

  5. Factors Affecting Aerosol Radiative Forcing

    NASA Astrophysics Data System (ADS)

    Wang, Jingxu; Lin, Jintai; Ni, Ruijing

    2016-04-01

    Rapid industrial and economic growth has meant a large amount of aerosols in the atmosphere with strong radiative forcing (RF) upon the climate system. Over parts of the globe, the negative forcing of aerosols has overcompensated for the positive forcing of greenhouse gases. Aerosol RF is determined by emissions and various chemical-transport-radiative processes in the atmosphere, a multi-factor problem whose individual contributors have not been well quantified. In this study, we analyze the major factors affecting RF of secondary inorganic aerosols (SIOAs, including sulfate, nitrate and ammonium), primary organic aerosol (POA), and black carbon (BC). We analyze the RF of aerosols produced by 11 major regions across the globe, including but not limited to East Asia, Southeast Asia, South Asia, North America, and Western Europe. Factors analyzed include population size, per capita gross domestic production (GDP), emission intensity (i.e., emissions per unit GDP), chemical efficiency (i.e., mass per unit emissions) and radiative efficiency (i.e., RF per unit mass). We find that among the 11 regions, East Asia produces the largest emissions and aerosol RF, due to relatively high emission intensity and a tremendous population size. South Asia produce the second largest RF of SIOA and BC and the highest RF of POA, in part due to its highest chemical efficiency among all regions. Although Southeast Asia also has large emissions, its aerosol RF is alleviated by its lowest chemical efficiency. The chemical efficiency and radiative efficiency of BC produced by the Middle East-North Africa are the highest across the regions, whereas its RF is lowered by a small per capita GDP. Both North America and Western Europe have low emission intensity, compensating for the effects on RF of large population sizes and per capita GDP. There has been a momentum to transfer industries to Southeast Asia and South Asia, and such transition is expected to continue in the coming years. The

  6. Radiation Transfer in the Atmosphere: Scattering

    NASA Technical Reports Server (NTRS)

    Mishchenko, M.; Travis, L.; Lacis, Andrew A.

    2014-01-01

    Sunlight illuminating the Earth's atmosphere is scattered by gas molecules and suspended particles, giving rise to blue skies, white clouds, and optical displays such as rainbows and halos. By scattering and absorbing the shortwave solar radiation and the longwave radiation emitted by the underlying surface, cloud and aerosol particles strongly affect the radiation budget of the terrestrial climate system. As a consequence of the dependence of scattering characteristics on particle size, morphology, and composition, scattered light can be remarkably rich in information on particle properties and thus provides a sensitive tool for remote retrievals of macro- and microphysical parameters of clouds and aerosols.

  7. Radiative transfer in spherical atmospheres

    NASA Astrophysics Data System (ADS)

    Kalkofen, W.; Wehrse, R.

    A method for defining spherical model atmospheres in radiative/convective and hydrostatic equilibrium is presented. A finite difference form is found for the transfer equation and a matrix operator is developed as the discrete space analog (in curvilinear coordinates) of a formal integral in plane geometry. Pressure is treated as a function of temperature. Flux conservation is maintained within the energy equation, although the correct luminosity transport must be assigned for any given level of the atmosphere. A perturbed integral operator is used in a complete linearization of the transfer and constraint equations. Finally, techniques for generating stable solutions in economical computer time are discussed.

  8. Models for infrared atmospheric radiation

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.

    1976-01-01

    Line and band models for infrared spectral absorption are discussed. Radiative transmittance and integrated absorptance of Lorentz, Doppler, and voigt line profiles were compared for a range of parameters. It was found that, for the intermediate path lengths, the combined Lorentz-Doppler (Voigt) profile is essential in calculating the atmospheric transmittance. Narrow band model relations for absorptance were used to develop exact formulations for total absorption by four wide band models. Several continuous correlations for the absorption of a wide band model were compared with the numerical solutions of the wide band models. By employing the line-by-line and quasi-random band model formulations, computational procedures were developed for evaluating transmittance and upwelling atmospheric radiance. Homogeneous path transmittances were calculated for selected bands of CO, CO2, and N2O and compared with experimental measurements. The upwelling radiance and signal change in the wave number interval of the CO fundamental band were also calculated.

  9. Radiative transfer in the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Manning, Amanda J. L.

    In recent years, much debate has surrounded phenomena such as the depletion of the ozone layer and the onset of greenhouse warming, which have occurred due to the changing concentrations of various constituents in the earth's atmosphere. The influx into the middle atmosphere of unnatural quantities of trace gases such as carbon dioxide and methane is likely to affect global climate both adversely and irreversibly. In order to model the response of the atmosphere to these changes, and to evaluate the relative importance of various gases in the interlinked radiative, dynamical, and chemical processes taking place, it is vital that we understand as fully as possible the role played by radiative transfer. To this end, a detailed yet flexible numerical model, covering the entire infrared spectrum, was developed for the study of radiative transfer processes in the stratosphere and mesosphere. The scheme is intended to be as accurate as possible within the constraints of available computer resources, and to produce reference heating rates against which those derived using more approximate methods may be checked. Particular consideration was given to minor constituents, including water vapor, methane, and nitrous oxide, whose roles were underestimated in many previous studies, and to minor spectral bands of major constituents, such as the 4.3 micron and 10 micron bands of carbon dioxide and the 14.3 micron band of ozone, whose importance with regard to the radiative balance of the middle atmosphere has not yet been fully evaluated. Considerable attention is paid to the calculation of atmospheric transmittance: the sensitivity of the heating rates to the choice of narrow band Goody or Malkmus model transmittances, as opposed to those generated using the high-resolution GENLN2 line-by-line model is assessed. Diffuse radiation is accounted for by explicit Gaussian integration over zenith angle, and the way in which heating rates thus generated differ from those derived with

  10. Radiative Transfer in the Middle Atmosphere

    NASA Astrophysics Data System (ADS)

    Manning, Amanda J. L.

    Available from UMI in association with The British Library. Requires signed TDF. In recent years, much debate has surrounded phenomena such as the depletion of the ozone layer and the onset of greenhouse warming, which have occurred due to the changing concentrations of various constituents in the earth's atmosphere. The influx into the middle atmosphere of unnatural quantities of trace gases such as carbon dioxide and methane is likely to affect global climate both adversely and irreversibly. In order to model the response of the atmosphere to these changes, and to evaluate the relative importance of various gases in the interlinked radiative, dynamical and chemical processes taking place, it is vital that we understand as fully as possible the role played by radiative transfer. To this end, a detailed yet flexible numerical model, covering the entire infrared spectrum, has been developed for the study of radiative transfer processes in the stratosphere and mesosphere. The scheme is intended to be as accurate as possible within the constraints of available computer resources, and to produce reference heating rates against which those derived using more approximate methods may be checked. Particular consideration has been given to minor constituents, including water vapour, methane and nitrous oxide, whose roles have been underestimated in many previous studies, and to minor spectral bands of major constituents, such as the 4.3 μm and 10 μm bands of carbon dioxide and the 14.3 μm band of ozone, whose importance with regard to the radiative balance of the middle atmosphere has not yet been fully evaluated. Considerable attention is paid to the calculation of atmospheric transmittance: the sensitivity of the heating rates to the choice of narrow band Goody or Malkmus model transmittances, as opposed to those generated using the high-resolution GENLN2 line -by-line model, is assessed. Diffuse radiation is accounted for by explicit Gaussian integration over zenith

  11. Radiative transfer in atmosphere-sea ice-ocean system

    SciTech Connect

    Jin, Z.; Stamnes, K.; Weeks, W.F.; Tsay, S.C.

    1996-04-01

    Radiative energy is critical in controlling the heat and mass balance of sea ice, which significantly affects the polar climate. In the polar oceans, light transmission through the atmosphere and sea ice is essential to the growth of plankton and algae and, consequently, to the microbial community both in the ice and in the ocean. Therefore, the study of radiative transfer in the polar atmosphere, sea ice, and ocean system is of particular importance. Lacking a properly coupled radiative transfer model for the atmosphere-sea ice-ocean system, a consistent study of the radiative transfer in the polar atmosphere, snow, sea ice, and ocean system has not been undertaken before. The radiative transfer processes in the atmosphere and in the ice and ocean have been treated separately. Because the radiation processes in the atmosphere, sea ice, and ocean depend on each other, this separate treatment is inconsistent. To study the radiative interaction between the atmosphere, clouds, snow, sea ice, and ocean, a radiative transfer model with consistent treatment of radiation in the coupled system is needed and is under development.

  12. Atmospheric State, Cloud Microphysics and Radiative Flux

    DOE Data Explorer

    Mace, Gerald

    2008-01-15

    Atmospheric thermodynamics, cloud properties, radiative fluxes and radiative heating rates for the ARM Southern Great Plains (SGP) site. The data represent a characterization of the physical state of the atmospheric column compiled on a five-minute temporal and 90m vertical grid. Sources for this information include raw measurements, cloud property and radiative retrievals, retrievals and derived variables from other third-party sources, and radiative calculations using the derived quantities.

  13. BART: Bayesian Atmospheric Radiative Transfer fitting code

    NASA Astrophysics Data System (ADS)

    Cubillos, Patricio; Blecic, Jasmina; Harrington, Joseph; Rojo, Patricio; Lust, Nate; Bowman, Oliver; Stemm, Madison; Foster, Andrew; Loredo, Thomas J.; Fortney, Jonathan; Madhusudhan, Nikku

    2016-08-01

    BART implements a Bayesian, Monte Carlo-driven, radiative-transfer scheme for extracting parameters from spectra of planetary atmospheres. BART combines a thermochemical-equilibrium code, a one-dimensional line-by-line radiative-transfer code, and the Multi-core Markov-chain Monte Carlo statistical module to constrain the atmospheric temperature and chemical-abundance profiles of exoplanets.

  14. Radiation in the atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Titov, Dmitry V.; Bullock, Mark A.; Crisp, David; Renno, Nilton O.; Taylor, Fredric W.; Zasova, Ljudmilla V.

    This chapter reviews the observations of the radiative fluxes inside and outside the Venusian atmosphere, along with the available data about the planetary energy balance and the distribution of sources and sinks of radiative energy. We also briefly address the role of the heat budget on the atmospheric temperature structure, global circulation, thermodynamics, climate and evolution. We compare the main features of radiative balance on the terrestrial planets, and provide a general description of the radiative-convective equilibrium models used to study their atmospheres. We describe the physics of the greenhouse effect as it applies to the evolution of the Venusian climate, concluding with a summary of outstanding open issues.

  15. The Skylab concentrated atmospheric radiation project

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.; Marlatt, W. E.; Whitehead, V. S. (Principal Investigator)

    1975-01-01

    The author has identified the following significant results. Comparison of several existing infrared radiative transfer models under somewhat controlled conditions and with atmospheric observations of Skylab's S191 and S192 radiometers illustrated that the models tend to over-compute atmospheric attenuation in the window region of the atmospheric infrared spectra.

  16. Atmospheric radiation model for water surfaces

    NASA Technical Reports Server (NTRS)

    Turner, R. E.; Gaskill, D. W.; Lierzer, J. R.

    1982-01-01

    An atmospheric correction model was extended to account for various atmospheric radiation components in remotely sensed data. Components such as the atmospheric path radiance which results from singly scattered sky radiation specularly reflected by the water surface are considered. A component which is referred to as the virtual Sun path radiance, i.e. the singly scattered path radiance which results from the solar radiation which is specularly reflected by the water surface is also considered. These atmospheric radiation components are coded into a computer program for the analysis of multispectral remote sensor data over the Great Lakes of the United States. The user must know certain parameters, such as the visibility or spectral optical thickness of the atmosphere and the geometry of the sensor with respect to the Sun and the target elements under investigation.

  17. [Research on clouds affecting the spectra of solar ultraviolet radiation].

    PubMed

    Zhao, Xiao-Yan; Yan, Hai-Tao; Zhen, Zhi-Qiang; Tang, Zheng-Xin; Wang, Hui

    2011-01-01

    In the present paper, using UV CCD optical multi-channel analyzer, the solar ultraviolet radiation spectra under the conditions of cloud cover were measured, and the impact of clouds on the solar ultraviolet radiation spectra were studied mostly. The results of spectral analysis showed that the intensity of solar ultraviolet radiation spectra was weakened by the clouds. The solar ultraviolet radiation spectral intensity attenuation depended on the wavelength and decreased with decreasing wavelength. The greater the cloud cover, the stronger the attenuation, The solar ultraviolet radiation spectral intensity at wavelengths below 315 nm was affected relatively less by the cloud cover. These results have more important practical applications. When we use solar ultraviolet radiation spectrum to study the atmospheric composition, we should choose the spectral band that is less affected by the atmospheric environment.

  18. Spectrally Invariant Approximation within Atmospheric Radiative Transfer

    NASA Technical Reports Server (NTRS)

    Marshak, A.; Knyazikhin, Y.; Chiu, J. C.; Wiscombe, W. J.

    2011-01-01

    Certain algebraic combinations of single scattering albedo and solar radiation reflected from, or transmitted through, vegetation canopies do not vary with wavelength. These spectrally invariant relationships are the consequence of wavelength independence of the extinction coefficient and scattering phase function in vegetation. In general, this wavelength independence does not hold in the atmosphere, but in cloud-dominated atmospheres the total extinction and total scattering phase function vary only weakly with wavelength. This paper identifies the atmospheric conditions under which the spectrally invariant approximation can accurately describe the extinction and scattering properties of cloudy atmospheres. The validity of the assumptions and the accuracy of the approximation are tested with 1D radiative transfer calculations using publicly available radiative transfer models: Discrete Ordinate Radiative Transfer (DISORT) and Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART). It is shown for cloudy atmospheres with cloud optical depth above 3, and for spectral intervals that exclude strong water vapor absorption, that the spectrally invariant relationships found in vegetation canopy radiative transfer are valid to better than 5%. The physics behind this phenomenon, its mathematical basis, and possible applications to remote sensing and climate are discussed.

  19. Direct EPP Affects on the Middle Atmosphere

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.

    2011-01-01

    Energetic precipitating particles (EPPs) can cause significant direct constituent changes in the mesosphere and stratosphere (middle atmosphere) during certain periods. Both protons and electrons can influence the polar middle atmosphere through ionization and dissociation processes. EPPs can enhance HOx (H, OH, HO2) through the formation of positive ions followed by complex ion chemistry and NOx (N, NO, NO2) through the dissociation of molecular nitrogen. The HOx increases result in direct ozone destruction in the mesosphere and upper stratosphere via several catalytic loss cycles. Such middle atmospheric HOx-caused ozone loss is rather short-lived due to the relatively short lifetime (hours) of the HOx constituents. The NOx family has a considerably longer lifetime than the HOx family and can also lead to catalytic ozone destruction. EPP-caused enhancements of the NOx family can affect ozone directly, if produced in the stratosphere. Ozone decreases from the EPPs lead to a reduction in atmospheric heating and, subsequent atmospheric cooling. Conversely, EPPs can cause direct atmospheric heating through Joule heating. Measured HOx constituents OH and HO2 showed increases due to solar protons. Observed NOx constituents NO and NO2 were enhanced due to both solar protons and precipitating electrons. Other hydrogen- and nitrogen-ocntaining constituents were also measured to be directly influenced by EPPs, including N2O, HNO3, HO2NO2, N2OS, H2O2, ClONO2, HCl, and HOCl. Observed constituents ClO and CO were directly affected by EPPs as well. Many measurements indicated significant direct ozone decreases. A significant number of satellites housed instruments, which observed direct EPP-caused atmospheric effects, including Nimbus 4 (BUV), Nimbus 7 (SBUV), several NOAA platforms (SBUV/2), SME, UARS (HALOE, CLAES), SCISAT-1 (ACE-FTS), Odin (OSIRIS), Envisat-l (GOMOS, MIPAS, SCIAMACHY), and Aura (MLS). Measurements by rockets and ground-based radar also indicated EPP direct

  20. 1-D Radiative-Convective Model for Terrestrial Exoplanet Atmospheres

    NASA Astrophysics Data System (ADS)

    Leung, Cecilia W. S.; Robinson, Tyler D.

    2016-10-01

    We present a one dimensional radiative-convective model to study the thermal structure of terrestrial exoplanetary atmospheres. The radiative transfer and equilibrium chemistry in our model is based on similar methodologies in models used for studying Extrasolar Giant Planets (Fortney et al. 2005b.) We validated our model in the optically thin and thick limits, and compared our pressure-temperature profiles against the analytical solutions of Robinson & Catling (2012). For extrasolar terrestrial planets with pure hydrogen atmospheres, we evaluated the effects of H2-H2 collision induced absorption and identified the purely roto-translational band in our modeled spectra. We also examined how enhanced atmospheric metallicities affect the temperature structure, chemistry, and spectra of terrestrial exoplanets. For a terrestrial extrasolar planet whose atmospheric compostion is 100 times solar orbiting a sun-like star at 2 AU, our model resulted in a reducing atmosphere with H2O, CH4, and NH3 as the dominant greenhouse gases.

  1. Tests of Exoplanet Atmospheric Radiative Transfer Codes

    NASA Astrophysics Data System (ADS)

    Harrington, Joseph; Challener, Ryan; DeLarme, Emerson; Cubillos, Patricio; Blecic, Jasmina; Foster, Austin; Garland, Justin

    2016-10-01

    Atmospheric radiative transfer codes are used both to predict planetary spectra and in retrieval algorithms to interpret data. Observational plans, theoretical models, and scientific results thus depend on the correctness of these calculations. Yet, the calculations are complex and the codes implementing them are often written without modern software-verification techniques. In the process of writing our own code, we became aware of several others with artifacts of unknown origin and even outright errors in their spectra. We present a series of tests to verify atmospheric radiative-transfer codes. These include: simple, single-line line lists that, when combined with delta-function abundance profiles, should produce a broadened line that can be verified easily; isothermal atmospheres that should produce analytically-verifiable blackbody spectra at the input temperatures; and model atmospheres with a range of complexities that can be compared to the output of other codes. We apply the tests to our own code, Bayesian Atmospheric Radiative Transfer (BART) and to several other codes. The test suite is open-source software. We propose this test suite as a standard for verifying current and future radiative transfer codes, analogous to the Held-Suarez test for general circulation models. This work was supported by NASA Planetary Atmospheres grant NX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G.

  2. Space, Atmospheric, and Terrestrial Radiation Environments

    NASA Technical Reports Server (NTRS)

    Barth, Janet L.; Dyer, C. S.; Stassinopoulos, E. G.

    2003-01-01

    The progress on developing models of the radiation environment since the 1960s is reviewed with emphasis on models that can be applied to predicting the performance of microelectronics used in spacecraft and instruments. Space, atmospheric, and ground environments are included. It is shown that models must be adapted continually to account for increased understanding of the dynamics of the radiation environment and the changes in microelectronics technology. The IEEE Nuclear and Space Radiation Effects Conference is a vital forum to report model progress to the radiation effects research community.

  3. Carbon Monoxide Affecting Planetary Atmospheric Chemistry

    NASA Astrophysics Data System (ADS)

    He, Chao; Horst, Sarah

    2016-10-01

    Atmospheric hazes are present in a range of solar system and extrasolar planetary atmospheres, and organic hazes, such as that in Titan's atmosphere, could be a source of prebiotic molecules.1 However, the chemistry occurring in planetary atmospheres and the resulting chemical structures are still not clear. Numerous experimental simulations2 have been carried out in the laboratory to understand the chemistry in N2/CH4 atmospheres, but very few simulations4 have included CO in their initial gas mixtures, which is an important component in many N2/CH4 atmospheres including Titan, Triton, and Pluto.3 Here we have conducted a series of atmosphere simulation experiments using AC glow discharge (cold plasma) as energy source to irradiate reactions in gas mixtures of CO, CH4, and N2 with a range of CO mixing ratios (from 0, 0.05%, 0.2%, 0.5%, 1%, 2.5%, to 5%) at low temperature (~100 K). Gas phase products are monitored during the reaction by quadrupole mass spectrometer (MS), and solid phase products are analyzed by solution-state nuclear magnetic resonance spectroscopy (NMR). MS results show that with the increase of CO in the initial gases, the production of nitrogenous organic molecules increases while the production of hydrogen molecules decreases in the gas phase. NMR measurements of the solid phase products show that with the increase of CO, hydrogen atoms bonded to nitrogen or oxygen in unsaturated structures increase while those bonded to saturated carbon decrease, which means more unsaturated species and less saturated species formed with the addition of CO. MS and NMR results demonstrate that the inclusion of CO affects the compositions of both gas and solid phase products, indicating that CO has an important impact on the chemistry occurring in our experiments and probably in planetary atmospheres.1. Hörst, S. M., et al. 2012, AsBio, 12, 8092. Cable, M. L., et al. 2012, Chem. Rev., 112, 18823. Lutz, B. L., et al. 1983, Sci, 220, 1374; Greaves, J. S., et al

  4. Radiative Energy Balance in the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Titov, Dmitrij V.; Piccioni, Giuseppe; Drossart, Pierre; Markiewicz, Wojciech J.

    This chapter reviews the observations of the radiative fluxes inside and outside the Venusian atmosphere, along with the available data about the planetary energy balance and the distribution of sources and sinks of radiative energy. We also briefly address the role of the radiation on the atmospheric temperature structure, global circulation, thermodynamics, climate and evolution of Venus and compare the main features of radiative balance on the terrestrial planets. We describe the physics of the greenhouse effect as it applies to the evolution of the Venusian climate, concluding with a summary of outstanding open issues. The article is to a great extent based on the paper by Titov et al. [2007] expanded byincluding recent results from the Venus Express observations relevant to the topic.

  5. Overview of Atmospheric Ionizing Radiation (AIR)

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Maiden, D. L.; Goldhagen, P.; Tai, H.; Shinn, J. L.

    2003-01-01

    The SuperSonic Transport (SST) development program within the US was based at the Langley Research Center as was the Apollo radiation testing facility (Space Radiation Effects Laboratory) with associated radiation research groups. It was natural for the issues of the SST to be first recognized by this unique combination of research programs. With a re-examination of the technologies for commercial supersonic flight and the possible development of a High Speed Civil Transport (HSCT), the remaining issues of the SST required resolution. It was the progress of SST radiation exposure research program founded by T. Foelsche at the Langley Research Center and the identified remaining issues after that project over twenty-five years ago which became the launch point of the current atmospheric ionizing radiation (AIR) research project. Added emphasis to the need for reassessment of atmospheric radiation resulted from the major lowering of the recommended occupational exposure limits, the inclusion of aircrew as radiation workers, and the recognition of civil aircrew as a major source of occupational exposures. Furthermore, the work of Ferenc Hajnal of the Environmental Measurements Laboratory brought greater focus to the uncertainties in the neutron flux at high altitudes. A re-examination of the issues involved was committed at the Langley Research Center and by the National Council on Radiation Protection (NCRP). As a result of the NCRP review, a new flight package was assembled and flown during solar minimum at which time the galactic cosmic radiation is at a maximum (June 1997). The present workshop is the initial analysis of the new data from that flight. The present paper is an overview of the status of knowledge of atmospheric ionizing radiations. We will re-examine the exposures of the world population and examine the context of aircrew exposures with implications for the results of the present research. A condensed version of this report was given at the 1998

  6. Thermal Infrared Radiative Forcing By Atmospheric Aerosol

    NASA Astrophysics Data System (ADS)

    Adhikari, Narayan

    The work mainly focuses on the study of thermal infrared (IR) properties of atmospheric greenhouse gases and aerosols, and the estimation of the aerosol-induced direct longwave (LW) radiative forcing in the spectral region 5-20 mum at the Earth's surface (BOA; bottom of the atmosphere) and the top of the atmosphere (TOA) in cloud-free atmospheric conditions. These objectives were accomplished by conducting case studies on clear sky, smoky, and dusty conditions that took place in the Great Basin of the USA in 2013. Both the solar and thermal IR measurements and a state-of-the-science radiative transfer model, the LBLDIS, a combination of the Line-By-Line Radiative Transfer Model and the Discrete Ordinate Radiative Transfer (DISORT) solver were employed for the study. The LW aerosol forcing is often not included in climate models because the aerosol effect on the LW is often assumed to be negligible. We lack knowledge of aerosol characteristics in the LW region, and aerosol properties exhibit high variability. We have found that the LW TOA radiative forcing due to fine mode aerosols, mainly associated with small biomass burning smoke particles, is + 0.4 W/m2 which seems to be small, but it is similar to the LW radiative forcing due to increase in CO2 concentration in the Earth's atmosphere since the preindustrial era of 1750 (+ 1.6 W/m 2). The LW radiative forcing due to coarse mode aerosols, associated with large airborne mineral dust particles, was found to be as much as + 5.02 W/m2 at the surface and + 1.71 W/m2 at the TOA. All of these significant positive values of the aerosol radiative forcing both at the BOA and TOA indicate that the aerosols have a heating effect in the LW range, which contributes to counterbalancing the cooling effect associated with the aerosol radiative forcing in the shortwave (SW) spectral region. In the meantime, we have found that LW radiative forcing by aerosols is highly sensitive to particle size and complex refractive indices of

  7. Radiative transfer in realistic planetary atmospheres. [bibliographies

    NASA Technical Reports Server (NTRS)

    Plass, G. N.; Kattawar, G. W.

    1982-01-01

    Some 40 publications that appeared in scientific journals from 1973 to 1981 as well as 45 scientific reports issued during the grant period are listed by title. Topics cover the development of a matrix operator theory of radiative transfer which made possible the exact model calculations of the radiance as a function of height in planetary atmospheres; calculation of the Mie phase matrix for various types of particles as well as for radiance and polarization in planetary atmospheres; analysis of high dispersion spectroscopic observations of Venus; calculation of curves of growth for Venus; the development of a theory for calculating radiative transfer in spherical shell atmospheres; investigations of zonal winds on Venus; and examination of Rayleigh scattering.

  8. Infrared radiation models for atmospheric methane

    NASA Technical Reports Server (NTRS)

    Cess, R. D.; Kratz, D. P.; Caldwell, J.; Kim, S. J.

    1986-01-01

    Mutually consistent line-by-line, narrow-band and broad-band infrared radiation models are presented for methane, a potentially important anthropogenic trace gas within the atmosphere. Comparisons of the modeled band absorptances with existing laboratory data produce the best agreement when, within the band models, spurious band intensities are used which are consistent with the respective laboratory data sets, but which are not consistent with current knowledge concerning the intensity of the infrared fundamental band of methane. This emphasizes the need for improved laboratory band absorptance measurements. Since, when applied to atmospheric radiation calculations, the line-by-line model does not require the use of scaling approximations, the mutual consistency of the band models provides a means of appraising the accuracy of scaling procedures. It is shown that Curtis-Godson narrow-band and Chan-Tien broad-band scaling provide accurate means of accounting for atmospheric temperature and pressure variations.

  9. Atmospheric Ionizing Radiation and Human Exposure

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Goldhagen, P.; Friedberg, W.; DeAngelis, G.; Clem, J. M.; Copeland, K.; Bidasaria, H. B.

    2004-01-01

    Atmospheric ionizing radiation is of interest, apart from its main concern of aircraft exposures, because it is a principal source of human exposure to radiations with high linear energy transfer (LET). The ionizing radiations of the lower atmosphere near the Earth s surface tend to be dominated by the terrestrial radioisotopes especially along the coastal plain and interior low lands and have only minor contributions from neutrons (11 percent). The world average is substantially larger but the high altitude cities especially have substantial contributions from neutrons (25 to 45 percent). Understanding the world distribution of neutron exposures requires an improved understanding of the latitudinal, longitudinal, altitude and spectral distribution that depends on local terrain and time. These issues are being investigated in a combined experimental and theoretical program. This paper will give an overview of human exposures and describe the development of improved environmental models.

  10. Atmospheric Ionizing Radiation and Human Exposure

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Mertens, Christopher J.; Goldhagen, Paul; Friedberg, W.; DeAngelis, G.; Clem, J. M.; Copeland, K.; Bidasaria, H. B.

    2005-01-01

    Atmospheric ionizing radiation is of interest, apart from its main concern of aircraft exposures, because it is a principal source of human exposure to radiations with high linear energy transfer (LET). The ionizing radiations of the lower atmosphere near the Earth s surface tend to be dominated by the terrestrial radioisotopes. especially along the coastal plain and interior low lands, and have only minor contributions from neutrons (11 percent). The world average is substantially larger but the high altitude cities especially have substantial contributions from neutrons (25 to 45 percent). Understanding the world distribution of neutron exposures requires an improved understanding of the latitudinal, longitudinal, altitude and spectral distribution that depends on local terrain and time. These issues are being investigated in a combined experimental and theoretical program. This paper will give an overview of human exposures and describe the development of improved environmental models.

  11. Satellite observation of atmospheric nuclear gamma radiation

    NASA Technical Reports Server (NTRS)

    Letaw, John R.; Share, G. H.; Kinzer, R. L.; Silberberg, R.; Chupp, E. L.

    1989-01-01

    Satellite observations of the spectrum of gamma radiation from the earth's atmosphere in the energy interval from 300 keV to 8.5 MeV were obtained with a gamma-ray spectrometer during 1980-1983. A total of 20 atmospheric line features are superimposed on a continuum background which is modeled using a power law with an index of -1.16. The line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric N-14 and O-16. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, are explained by Compton scattering of the annihilation line photons in traversing an average of 21 g/sq cm of atmosphere.

  12. Sensitivity of radiation absorbed in the ocean to atmospheric and oceanic parameters in the short wavelength region. I - Cloudless atmosphere

    NASA Astrophysics Data System (ADS)

    Masuda, Kazuhiko; Takashima, Tsutomu

    1988-08-01

    The effects of atmospheric and oceanic parameters on the measured shortwave radiation absorbed in the ocean and on the upward irradiance at the top of the atmosphere were investigated using a model atmosphere-ocean system under the conditions of cloudless atmosphere. The computations showed that, for theta(0) of about 45 deg, the absorbed radiation in the ocean depends mainly on the atmospheric turbidity. Precipitable water vapor and ozone in the atmosphere also affect the absorbed radiation, but they have little effect on the upward irradiance. The surface roughness and whitecaps have little effect on the absorbed radiation or the upward radiance if the surface wind speed is less than about 5 m/sec. Finally, the oceanic hydrosols have little effect on either of these characteristics except when they are of pure scattering type in a turbid condition.

  13. Atmospheric Ionizing Radiation (AIR) Project Review

    NASA Technical Reports Server (NTRS)

    Singleterry, R. C., Jr.; Wilson, J. W.; Whitehead, A. H.; Goldhagen, P. E.

    1999-01-01

    The National Council on Radiation Protection and Measurement (NCRP) and the National Academy of Science (NAS) established that the uncertainty in the data and models associated with the high-altitude radiation environment could and should be reduced. In response, the National Aeronautics and Space Administration (NASA) and the U.S. Department of Energy Environmental Measurements Laboratory (EML) created the Atmospheric Ionizing Radiation (AIR) Project under the auspices of the High Speed Research (HSR) Program Office at the Langley Research Center. NASA's HSR Program was developed to address the potential of a second-generation supersonic transport. A critical element focussed on the environmental issues, including the threat to crew and passengers posed by atmospheric radiation. Various international investigators were solicited to contribute instruments to fly on an ER-2 aircraft at altitudes similar to those proposed for the High Speed Civil Transport (HSCT). A list of participating investigators, their institutions, and instruments with quantities measured is presented. The flight series took place at solar minimum (radiation maximum) with northern, southern, and east/west flights. The investigators analyzed their data and presented preliminary results at the AIR Workshop in March, 1998. A review of these results are included.

  14. Infrared radiation models for atmospheric ozone

    NASA Technical Reports Server (NTRS)

    Kratz, David P.; Ces, Robert D.

    1988-01-01

    A hierarchy of line-by-line, narrow-band, and broadband infrared radiation models are discussed for ozone, a radiatively important atmospheric trace gas. It is shown that the narrow-band (Malkmus) model is in near-precise agreement with the line-by-line model, thus providing a means of testing narrow-band Curtis-Godson scaling, and it is found that this scaling procedure leads to errors in atmospheric fluxes of up to 10 percent. Moreover, this is a direct consequence of the altitude dependence of the ozone mixing ratio. Somewhat greater flux errors arise with use of the broadband model, due to both a lesser accuracy of the broadband scaling procedure and to inherent errors within the broadband model, despite the fact that this model has been tuned to the line-by-line model.

  15. Radiative transfer analyses of Titan's tropical atmosphere

    NASA Astrophysics Data System (ADS)

    Griffith, Caitlin A.; Doose, Lyn; Tomasko, Martin G.; Penteado, Paulo F.; See, Charles

    2012-04-01

    Titan's optical and near-IR spectra result primarily from the scattering of sunlight by haze and its absorption by methane. With a column abundance of 92 km amagat (11 times that of Earth), Titan's atmosphere is optically thick and only ˜10% of the incident solar radiation reaches the surface, compared to 57% on Earth. Such a formidable atmosphere obstructs investigations of the moon's lower troposphere and surface, which are highly sensitive to the radiative transfer treatment of methane absorption and haze scattering. The absorption and scattering characteristics of Titan's atmosphere have been constrained by the Huygens Probe Descent Imager/Spectral Radiometer (DISR) experiment for conditions at the probe landing site (Tomasko, M.G., Bézard, B., Doose, L., Engel, S., Karkoschka, E. [2008a]. Planet. Space Sci. 56, 624-247; Tomasko, M.G. et al. [2008b]. Planet. Space Sci. 56, 669-707). Cassini's Visual and Infrared Mapping Spectrometer (VIMS) data indicate that the rest of the atmosphere (except for the polar regions) can be understood with small perturbations in the high haze structure determined at the landing site (Penteado, P.F., Griffith, C.A., Tomasko, M.G., Engel, S., See, C., Doose, L., Baines, K.H., Brown, R.H., Buratti, B.J., Clark, R., Nicholson, P., Sotin, C. [2010]. Icarus 206, 352-365). However the in situ measurements were analyzed with a doubling and adding radiative transfer calculation that differs considerably from the discrete ordinates codes used to interpret remote data from Cassini and ground-based measurements. In addition, the calibration of the VIMS data with respect to the DISR data has not yet been tested. Here, VIMS data of the probe landing site are analyzed with the DISR radiative transfer method and the faster discrete ordinates radiative transfer calculation; both models are consistent (to within 0.3%) and reproduce the scattering and absorption characteristics derived from in situ measurements. Constraints on the atmospheric

  16. Satellite observation of atmospheric nuclear gamma radiation.

    PubMed

    Letaw, J R; Share, G H; Kinzer, R L; Silberberg, R; Chupp, E L; Forrest, D J; Rieger, E

    1989-02-01

    We present a satellite observation of the spectrum of gamma radiation from the Earth's atmosphere in the energy interval from 300 keV to 8.5 MeV. The data were accumulated by the gamma ray spectrometer on the Solar Maximum Mission over 3 1/2 years, from 1980 to 1983. The excellent statistical accuracy of the data allows 20 atmospheric line features to be identified. The features are superimposed on a continuum background which is modeled using a power law with index -1.16. Many of these features contain a blend of more than one nuclear line. All of these lines (with the exception of the 511-keV annihilation line) are Doppler broadened. Line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric 14N and 16O. Although we find no evidence for other production mechanisms, we cannot rule out significant contributions from direct excitation or spallation by primary cosmic ray protons. The relative intensities of the observed line features are in fair agreement with theoretical models; however, existing models are limited by the availability of neutron cross sections, especially at high energies. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, can be explained by Compton scattering of the annihilation line photons in traversing an average of approximately 21 g cm-2 of atmosphere.

  17. Planetary Atmosphere Dynamics and Radiative Transfer

    NASA Astrophysics Data System (ADS)

    Atkinson, David H.

    1996-01-01

    This research program has dealt with two projects in the field of planetary atmosphere dynamics and radiative energy transfer, one theoretical and one experimental. The first project, in radiative energy transfer, incorporated the capability to isolate and quantify the contribution of individual atmospheric components to the Venus radiative balance and thermal structure to greatly improve the current understanding of the radiative processes occurring within the Venus atmosphere. This is possible by varying the mixing ratios of each gas species, and the location, number density and aerosol size distributions of the clouds. This project was a continuation of the work initiated under a 1992 University Consortium Agreement. Under the just completed grant, work has continued on the use of a convolution-based algorithm that provided the capability to calculate the k coefficients of a gas mixture at different temperatures, pressures and spectral intervals from the separate k-distributions of the individual gas species. The second primary goal of this research dealt with the Doppler wind retrieval for the Successful Galileo Jupiter probe mission in December, 1995. In anticipation of the arrival of Galileo at Jupiter, software development continued to read the radioscience and probe/orbiter trajectory data provided by the Galileo project and required for Jupiter zonal wind measurements. Sample experiment radioscience data records and probe/orbiter trajectory data files provided by the Galileo Radioscience and Navigation teams at the Jet Propulsion Laboratory, respectively, were used for the first phase of the software development. The software to read the necessary data records was completed in 1995. The procedure by which the wind retrieval takes place begins with initial consistency checks of the raw data, preliminary data reductions, wind recoveries, iterative reconstruction of the probe descent profile, and refined wind recoveries. At each stage of the wind recovery

  18. Polarized Continuum Radiation from Stellar Atmospheres

    NASA Astrophysics Data System (ADS)

    Harrington, J. Patrick

    2015-10-01

    Continuum scattering by free electrons can be significant in early type stars, while in late type stars Rayleigh scattering by hydrogen atoms or molecules may be important. Computer programs used to construct models of stellar atmospheres generally treat the scattering of the continuum radiation as isotropic and unpolarized, but this scattering has a dipole angular dependence and will produce polarization. We review an accurate method for evaluating the polarization and limb darkening of the radiation from model stellar atmospheres. We use this method to obtain results for: (i) Late type stars, based on the MARCS code models (Gustafsson et al. 2008), and (ii) Early type stars, based on the NLTE code TLUSTY (Lanz and Hubeny 2003). These results are tabulated at http://www.astro.umd.edu/~jph/Stellar_Polarization.html. While the net polarization vanishes for an unresolved spherical star, this symmetry is broken by rapid rotation or by the masking of part of the star by a binary companion or during the transit of an exoplanet. We give some numerical results for these last cases.

  19. Thermal Radiation In The Lower Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Afanasenko, T. S.; Rodin, A. V.; Rodimova, O. B.; Tvorogov, S. D.

    Venus atmosphere is for a long time known for the strong greenhouse effect that gov- erns this unique climate system, however, the details of its radiative properties remains poorly known. In particular, the complexity of physics related to line broadening un- der Venus conditions results in major uncertainty of simulated infrared opacities and fluxes. Based on the theory of spectral line far wing and available spectroscopic in- formation, we have built an accurate and efficient model for thermal radiation under Venus conditions. Adopted assumptions on the spectral line contour at high pressures and its impact to the thermal balance were comprehensively tested. Simulations of thermal radiation intensities and fluxes show that they are highly dependent on spec- tral line formfactor. 1D thermal balance simulation taking into account dynamical heat transfer has resulted in quantitative evaluation of basic mechanisms that form green- house effect on Venus. In a wide altitude range between 30 and 50 km, dynamical heat transfer appears to substantially contribute to the maintenance of the present thermal profile. This work has been supported by RFBR grant 01-02-17481

  20. Prototype Operational Advances for Atmospheric Radiation Dose Rate Specification

    NASA Astrophysics Data System (ADS)

    Tobiska, W. K.; Bouwer, D.; Bailey, J. J.; Didkovsky, L. V.; Judge, K.; Garrett, H. B.; Atwell, W.; Gersey, B.; Wilkins, R.; Rice, D.; Schunk, R. W.; Bell, D.; Mertens, C. J.; Xu, X.; Crowley, G.; Reynolds, A.; Azeem, I.; Wiltberger, M. J.; Wiley, S.; Bacon, S.; Teets, E.; Sim, A.; Dominik, L.

    2014-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. The coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has developed innovative, new space weather observations that will become part of the toolset that is transitioned into operational use. One prototype operational system for providing timely information about the effects of space weather is SET's Automated Radiation Measurements for Aerospace Safety (ARMAS) system. ARMAS will provide the "weather" of the radiation environment to improve aircraft crew and passenger safety. Through several dozen flights the ARMAS project has successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time via Iridium satellites, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. We are extending the dose measurement domain above commercial aviation altitudes into the stratosphere with a collaborative project organized by NASA's Armstrong Flight Research Center (AFRC) called Upper-atmospheric Space and Earth Weather eXperiment (USEWX). In USEWX we will be flying on the ER-2 high altitude aircraft a micro dosimeter for

  1. Solar and thermal radiation in the Venus atmosphere

    NASA Technical Reports Server (NTRS)

    Moroz, V. I.; Ekonomov, A. P.; Moshkin, B. E.; Revercomb, H. E.; Sromovsky, L. A.; Schofield, J. T.

    1985-01-01

    Attention is given to the solar and thermal radiation fields of Venus. Direct measurements and the results of numerical models based on direct measurements are presented. Radiation outside the atmosphere is considered with emphasis placed on global energy budget parameters, spectral and angular dependences, spatial distribution, and temporal variations of solar and thermal radiation. Radiation fluxes inside the atmosphere below 90 km are also considered with attention given to the solar flux at the surface, solar and thermal radiation fluxes from 100 km to the surface, and radiative heating and cooling below 100 km.

  2. Relationships Among Top-of-atmosphere Radiation and Atmospheric State Variables in Observations and CESM

    NASA Astrophysics Data System (ADS)

    Trenberth, K. E.

    2015-12-01

    A detailed examination is made in both observations and the Community Earth System Model (CESM) of relationships among top-of-atmosphere (TOA) radiation and surface air temperatures, as well as water vapor, tropospheric temperatures and precipitation for 2000-2014 to assess the origins of radiative perturbations and climate feedbacks empirically. The 30-member CESM large ensemble coupled runs are analyzed. Both global and local relationships are examined. There is a lot more high frequency variability in radiative fluxes than in temperature, highlighting the role of clouds and transient weather systems in the radiation statistics. Surface temperatures respond to a radiative imbalance and also greatly affect the outgoing longwave radiation OLR), especially over land. However, tropospheric temperatures are much more influenced by clouds, which affect both absorbed solar radiation (ASR) and OLR, and with large compensation. The vertical structure of the CESM temperature profile tends to be top-heavy in the model, with too much deep convection and not enough lower stratospheric cooling as part of the response to tropospheric heating. There is too much ASR over the southern oceans and not enough in the tropics, and ENSO is too large in amplitude in this version of the model. However, the co-variability of monthly mean anomalies produces remarkably good replication of most of the observed relationships. Over the Warm Pool in the tropical western Pacific and Indian oceans, where non-local effects from the Walker circulation driven by the ENSO events are important, several related biases emerge: in response to high SST anomalies there is more precipitation, water vapor and cloud, and less ASR and OLR in the model than observed. Different model global mean trends are evident, however, and hint at too much positive cloud feedback in the model.

  3. A new one-dimensional radiative equilibrium model for investigating atmospheric radiation entropy flux.

    PubMed

    Wu, Wei; Liu, Yangang

    2010-05-12

    A new one-dimensional radiative equilibrium model is built to analytically evaluate the vertical profile of the Earth's atmospheric radiation entropy flux under the assumption that atmospheric longwave radiation emission behaves as a greybody and shortwave radiation as a diluted blackbody. Results show that both the atmospheric shortwave and net longwave radiation entropy fluxes increase with altitude, and the latter is about one order in magnitude greater than the former. The vertical profile of the atmospheric net radiation entropy flux follows approximately that of the atmospheric net longwave radiation entropy flux. Sensitivity study further reveals that a 'darker' atmosphere with a larger overall atmospheric longwave optical depth exhibits a smaller net radiation entropy flux at all altitudes, suggesting an intrinsic connection between the atmospheric net radiation entropy flux and the overall atmospheric longwave optical depth. These results indicate that the overall strength of the atmospheric irreversible processes at all altitudes as determined by the corresponding atmospheric net entropy flux is closely related to the amount of greenhouse gases in the atmosphere.

  4. Atmospheric radiation measurement program facilities newsletter, September 2001.

    SciTech Connect

    Holdridge, D. J.

    2001-10-10

    Our Changing Climate--Is our climate really changing? How do we measure climate change? How can we predict what Earth's climate will be like for generations to come? One focus of the Atmospheric Radiation Measurement (ARM) Program is to improve scientific climate models enough to achieve reliable regional prediction of future climate. According to the Environmental Protection Agency (EPA), the global mean surface temperature has increased by 0.5-1.0 F since the late 19th century. The 20th century's 10 warmest years all occurred in the last 15 years of the century, with 1998 being the warmest year of record. The global mean surface temperature is measured by a network of temperature-sensing instruments distributed around the world, including ships, ocean buoys, and weather stations on land. The data from this network are retrieved and analyzed by various organizations, including the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and the World Meteorological Organization. Worldwide temperature records date back to 1860. To reconstruct Earth's temperature history before 1860, scientists use limited temperature records, along with proxy indicators such as tree rings, pollen records, and analysis of air frozen in ancient ice. The solar energy received from the sun drives Earth's weather and climate. Some of this energy is reflected and filtered by the atmosphere, but most is absorbed by Earth's surface. The absorbed solar radiation warms the surface and is re-radiated as heat energy into the atmosphere. Some atmospheric gases, called greenhouse gases, trap some of the re-emitted heat, keeping the surface temperature regulated and suitable for sustaining life. Although the greenhouse effect is natural, some evidence indicates that human activities are producing increased levels of some greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Scientists believe that the combustion of fossil fuels is

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  6. Atmospheric Radiation Measurement Program facilities newsletter, May 2000.

    SciTech Connect

    Sisterson, D.L.

    2000-06-01

    This month the authors will visit an ARM CART site with a pleasant climate: the Tropical Western Pacific (TWP) CART site, along the equator in the western Pacific Ocean. The TWP locale lies between 10 degrees North latitude and 10 degrees South latitude and extends from Indonesia east-ward beyond the international date line. This area was selected because it is in and around the Pacific warm pool, the area of warm sea-surface temperatures that determine El Nino/La Nina episodes. The warm pool also adds heat and moisture to the atmosphere and thus fuels cloud formation. Understanding the way tropical clouds and water vapor affect the solar radiation budget is a focus of the ARM Program. The two current island-based CART sites in the TWP are in Manus Province in Papua New Guinea and on Nauru Island.

  7. Interference of spectral lines in thermal radiation from the lower atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Afanasenko, T. S.; Rodin, A. V.

    2007-03-01

    The absorption spectrum and thermal radiation fluxes in the lower atmosphere of Venus are calculated using the theory of molecular state interference in the strong collision approximation. Comparison is made with the absorption and radiative transfer calculations in terms of the statistical theory of collisional line broadening and based on an empirical form factor. The calculations show that the line broadening mechanism does not affect the thermal regime of the atmosphere at heights above 60 km, but affects significantly the behavior of the greenhouse effect below the cloud layer.

  8. Introduction to the Theory of Atmospheric Radiative Transfer

    NASA Technical Reports Server (NTRS)

    Buglia, J. J.

    1986-01-01

    The fundamental physical and mathematical principles governing the transmission of radiation through the atmosphere are presented, with emphasis on the scattering of visible and near-IR radiation. The classical two-stream, thin-atmosphere, and Eddington approximations, along with some of their offspring, are developed in detail, along with the discrete ordinates method of Chandrasekhar. The adding and doubling methods are discussed from basic principles, and references for further reading are suggested.

  9. Spectrally-Invariant Approximation Within Atmospheric Radiative Transfer

    NASA Technical Reports Server (NTRS)

    Marshak, A.; Knyazikhin, Y.; Chiu, J. C.; Wiscombe, W. J.

    2011-01-01

    Certain algebraic combinations of single scattering albedo and solar radiation reflected from, or transmitted through, vegetation canopies do not vary with wavelength. These "spectrally invariant relationships" are the consequence of wavelength independence of the extinction coefficient and scattering phase function in vegetation. In general, this wavelength independence does not hold in the atmosphere, but in clouddominated atmospheres the total extinction and total scattering phase function vary only weakly with wavelength. This paper identifies the atmospheric conditions under which the spectrally invariant approximation can accurately describe the extinction. and scattering properties of cloudy atmospheres. The validity of the assumptions and the accuracy of the approximation are tested with ID radiative transfer calculations using publicly available radiative transfer models: Discrete Ordinate Radiative Transfer (DISORT) and Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART). It is shown for cloudy atmospheres with cloud optical depth above 3, and for spectral intervals that exclude strong water vapor absorption, that the spectrally invariant relationships found in vegetation canopy radiative transfer are valid to better than 5%. The physics behind this phenomenon, its mathematical basis, and possible applications to remote sensing and climate are discussed.

  10. Radiation-affected laminar flame quenching

    SciTech Connect

    Arpaci, V.S.; Tabaczynski, R.J.

    1984-08-01

    A radiation number describing all effects of radiation (emission, absorption, and scattering) near a wall is introduced. The increase in the Peclet number characterizing the flame quench distance and the decrease in flame temperature are shown in terms of this radiation number. Finally, the above considerations have made it possible to qualitatively show that the contribution of radiation to the heat transfer and the laminar flame quenching in small diesel engines can be as much as 35 percent. 27 references.

  11. Space Weather Nowcasting of Atmospheric Ionizing Radiation for Aviation Safety

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.; Wilson, John W.; Blattnig, Steve R.; Solomon, Stan C.; Wiltberger, J.; Kunches, Joseph; Kress, Brian T.; Murray, John J.

    2007-01-01

    There is a growing concern for the health and safety of commercial aircrew and passengers due to their exposure to ionizing radiation with high linear energy transfer (LET), particularly at high latitudes. The International Commission of Radiobiological Protection (ICRP), the EPA, and the FAA consider the crews of commercial aircraft as radiation workers. During solar energetic particle (SEP) events, radiation exposure can exceed annual limits, and the number of serious health effects is expected to be quite high if precautions are not taken. There is a need for a capability to monitor the real-time, global background radiations levels, from galactic cosmic rays (GCR), at commercial airline altitudes and to provide analytical input for airline operations decisions for altering flight paths and altitudes for the mitigation and reduction of radiation exposure levels during a SEP event. The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model is new initiative to provide a global, real-time radiation dosimetry package for archiving and assessing the biologically harmful radiation exposure levels at commercial airline altitudes. The NAIRAS model brings to bear the best available suite of Sun-Earth observations and models for simulating the atmospheric ionizing radiation environment. Observations are utilized from ground (neutron monitors), from the atmosphere (the METO analysis), and from space (NASA/ACE and NOAA/GOES). Atmospheric observations provide the overhead shielding information and the ground- and space-based observations provide boundary conditions on the GCR and SEP energy flux distributions for transport and dosimetry simulations. Dose rates are calculated using the parametric AIR (Atmospheric Ionizing Radiation) model and the physics-based HZETRN (High Charge and Energy Transport) code. Empirical models of the near-Earth radiation environment (GCR/SEP energy flux distributions and geomagnetic cut-off rigidity) are benchmarked

  12. New radiosonde techniques to measure radiation profiles through the atmosphere

    NASA Astrophysics Data System (ADS)

    Kräuchi, Andreas; Philipona, Rolf; Romanens, Gonzague; Levrat, Gilbert

    2013-04-01

    Solar and thermal radiation fluxes are usually measured at Earth's surface and at the top of the atmosphere. Here we show radiosonde techniques that allow measuring radiation flux profiles and the radiation budget from the Earth's surface to above 30 km in the stratosphere. During two-hour flights solar shortwave and thermal longwave irradiance, downward and upward, is measured with four individual sensors at one-second resolution, along with standard PTU radiosonde profiles. Daytime and nighttime shortwave and longwave radiation measurements, and 24 hours surface measurements, allow determining radiation budget- and total net radiation profiles through the atmosphere. We use a double balloon technique to prevent pendulum motion during the ascent and to keep the sonde as horizontal as possible. New techniques using auto controlled airplanes are now investigated to retrieve the sonde after release at a certain altitude and to land it if possible at the launch station.

  13. Atmospheric Aerosols and Earth's Radiative Budget

    NASA Technical Reports Server (NTRS)

    Toon, O. B.; Condon, Estelle (Technical Monitor)

    1997-01-01

    During recent years interest in the radiative properties of aerosols has revived as it has been recognized that their potential radiative forcing rivals that of greenhouse gases, and that the uncertainty in their radiative forcing is so large that meaningful simulations of the climate cannot be done without considering them. In this talk I will review some of the direct and indirect effects that aerosols might have on climate. I will identify areas where considerable progress has been made during the past decade, and I will also highlight areas in which significant uncertainties remain. Unfortunately there is a lot of laboratory, field and theoretical work which remains to be done before we can reduce significantly the uncertainties in determining the radiative forcing by aerosols.

  14. Influence of Dust Loading on Atmospheric Ionizing Radiation on Mars

    NASA Technical Reports Server (NTRS)

    Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

    2014-01-01

    Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

  15. Influence of dust loading on atmospheric ionizing radiation on Mars

    NASA Astrophysics Data System (ADS)

    Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

    2014-01-01

    Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

  16. AN ANALYTIC RADIATIVE-CONVECTIVE MODEL FOR PLANETARY ATMOSPHERES

    SciTech Connect

    Robinson, Tyler D.; Catling, David C.

    2012-09-20

    We present an analytic one-dimensional radiative-convective model of the thermal structure of planetary atmospheres. Our model assumes that thermal radiative transfer is gray and can be represented by the two-stream approximation. Model atmospheres are assumed to be in hydrostatic equilibrium, with a power-law scaling between the atmospheric pressure and the gray thermal optical depth. The convective portions of our models are taken to follow adiabats that account for condensation of volatiles through a scaling parameter to the dry adiabat. By combining these assumptions, we produce simple, analytic expressions that allow calculations of the atmospheric-pressure-temperature profile, as well as expressions for the profiles of thermal radiative flux and convective flux. We explore the general behaviors of our model. These investigations encompass (1) worlds where atmospheric attenuation of sunlight is weak, which we show tend to have relatively high radiative-convective boundaries; (2) worlds with some attenuation of sunlight throughout the atmosphere, which we show can produce either shallow or deep radiative-convective boundaries, depending on the strength of sunlight attenuation; and (3) strongly irradiated giant planets (including hot Jupiters), where we explore the conditions under which these worlds acquire detached convective regions in their mid-tropospheres. Finally, we validate our model and demonstrate its utility through comparisons to the average observed thermal structure of Venus, Jupiter, and Titan, and by comparing computed flux profiles to more complex models.

  17. Solar Atmospheric Magnetic Energy Coupling: Radiative Redistribution Efficiency

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  18. Radiation doses from Hanford site releases to the atmosphere

    SciTech Connect

    Farris, W.T.; Napier, B.A.; Ikenberry, T.A.

    1994-06-01

    Radiation doses to individuals were estimated for the years 1944-1992. The dose estimates were based on the radioactive-releases from the Hanford Site in south central Washington. Conceptual models and computer codes were used to reconstruct doses through the early 1970s. The published Hanford Site annual environmental data were used to complete the does history through 1992. The most significant exposure pathway was found to be the consumption of cow`s milk containing iodine-131. For the atmospheric pathway, median cumulative dose estimates to the thyroid of children ranged from < 0.1 to 235 rad throughout the area studied. The geographic distribution of the dose levels was directly related to the pattern of iodine-131 deposition and was affected by the distribution of commercial milk and leafy vegetables. For the atmospheric pathway, the-highest estimated cumulative-effective-dose-equivalent (EDE) to an adult was estimated to be 1 rem at Ringold, Washington for the period 1944-1992. For the Columbia River pathway, cumulative EDE estimates ranged from <0.5 to l.5 rem cumulative dose to maximally exposed adults downriver from the Hanford Site for the years 1944-1992. The most significant river exposure pathway was consumption of resident fish containing phosphorus-32 and zinc-65.

  19. Atmospheric Radiation Measurement Climate Research Facility (ACRF) Annual Report 2008

    SciTech Connect

    LR Roeder

    2008-12-01

    The Importance of Clouds and Radiation for Climate Change: The Earth’s surface temperature is determined by the balance between incoming solar radiation and thermal (or infrared) radiation emitted by the Earth back to space. Changes in atmospheric composition, including greenhouse gases, clouds, and aerosols, can alter this balance and produce significant climate change. Global climate models (GCMs) are the primary tool for quantifying future climate change; however, there remain significant uncertainties in the GCM treatment of clouds, aerosol, and their effects on the Earth’s energy balance. In 1989, the U.S. Department of Energy (DOE) Office of Science created the Atmospheric Radiation Measurement (ARM) Program to address scientific uncertainties related to global climate change, with a specific focus on the crucial role of clouds and their influence on the transfer of radiation in the atmosphere. To reduce these scientific uncertainties, the ARM Program uses a unique twopronged approach: • The ARM Climate Research Facility, a scientific user facility for obtaining long-term measurements of radiative fluxes, cloud and aerosol properties, and related atmospheric characteristics in diverse climate regimes; and • The ARM Science Program, focused on the analysis of ACRF and other data to address climate science issues associated with clouds, aerosols, and radiation, and to improve GCMs. This report provides an overview of each of these components and a sample of achievements for each in fiscal year (FY) 2008.

  20. 3D Radiative Transfer in Cloudy Atmospheres

    NASA Astrophysics Data System (ADS)

    Marshak, Alexander; Davis, Anthony

    Developments in three-dimensional cloud radiation over the past few decades are assessed and distilled into this contributed volume. Chapters are authored by subject-matter experts who address a broad audience of graduate students, researchers, and anyone interested in cloud-radiation processes in the solar and infrared spectral regions. After two introductory chapters and a section on the fundamental physics and computational techniques, the volume extensively treats two main application areas: the impact of clouds on the Earth's radiation budget, which is an essential aspect of climate modeling; and remote observation of clouds, especially with the advanced sensors on current and future satellite missions. http://www.springeronline.com/alert/article?a=3D1_1fva7w_1j826l_41z_6

  1. Effect of a finite ionization rate on the radiative heating of outer planet atmospheric entry probes

    NASA Technical Reports Server (NTRS)

    Nelson, H. F.

    1982-01-01

    The influence of finite rate ionization in the inviscid gas just behind the stagnation shock wave on the radiative heating of probes entering the hydrogen-helium atmosphere of the major plants was investigated. Two opposing conclusions were reached as to how the ionization rate assumption affects the radiative transfer. Hydrogen-helium shock waves with a cold nonblowing wall boundary condition at the probe heat shield are emphasized. The study is limited to the stagnation shock layer.

  2. Efficient vector radiative transfer calculations in vertically inhomogeneous cloudy atmospheres.

    PubMed

    van Diedenhoven, Bastiaan; Hasekamp, Otto P; Landgraf, Jochen

    2006-08-10

    Accurate radiative transfer calculations in cloudy atmospheres are generally time consuming, limiting their practical use in satellite remote sensing applications. We present a model to efficiently calculate the radiative transfer of polarized light in atmospheres that contain homogeneous cloud layers. This model combines the Gauss-Seidel method, which is efficient for inhomogeneous cloudless atmospheres, with the doubling method, which is efficient for homogeneous cloud layers. Additionally to reduce the computational effort for radiative transfer calculations in absorption bands, the cloud reflection and transmission matrices are interpolated over the absorption and scattering optical thicknesses within the cloud layer. We demonstrate that the proposed radiative transfer model in combination with this interpolation technique is efficient for the simulation of satellite measurements for inhomogeneous atmospheres containing one homogeneous cloud layer. For example, the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) measurements in the oxygen A band (758-773 nm) and the Hartley-Huggins ozone band (295-335 nm) with a spectral resolution of 0.4 nm can be simulated for these atmospheres within 1 min on a 2.8 GHz PC with an accuracy better than 0.1%.

  3. Ionosphere-Earth current density affecting clouds and atmospheric dynamics

    NASA Astrophysics Data System (ADS)

    Tinsley, Brian; Burns, Gary

    Ionosphere-Earth current density affecting clouds and atmospheric dynamics Correlations of atmospheric dynamics, cloud cover, and precipitation with changes in external and internal inputs that affect the downward ionosphere-earth current density, Jz, through the atmosphere have been reported on day-to-day, decadal, century and longer timescales. Such inputs are changes in the cosmic ray flux; in the interplanetary electric field; in solar energetic particles; in relativistic electron precipitation; and in the upward current output of global thunderstorm activity. The interplanetary electric field and relativistic electron and thunderstorm inputs affect Jz while not changing the tropospheric ionization rate, thus ruling out ion-mediated nucleation as the mechanism affecting the cloud processes. Modeling suggests that charge modulation of aerosol scavenging (CMAS) in clouds affects cloud microphysics and can account for the correlations. The CMAS effects are different for cold clouds as compared to warm clouds, and vary with the size of the condensation nuclei and ice-forming nuclei. CMAS effects on cold and warm cloud lifetimes can account for observed changes in cloud cover on day-to-day and decadal time scales. CMAS effects on precipitation from cold clouds can account for increases in winter storm vorticity in cyclogenesis regions. Increases in cyclonic vorticity in these regions generates anticyclonic blocking a half Rossby wavelength downstream. These affect storm tracks and the advection of cold Arctic air in winter onto the continents. Observations, theory and modeling of cloud microphysics supporting these chains of processes will be reviewed, but the needed modeling of resolved clouds and their insertion into GCMs is complex and demanding, and has yet to be undertaken.

  4. 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

  5. Radiative equilibrium model of Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Samuelson, R. E.

    1983-01-01

    The present global radiative equilibrium model for the Saturn satellite Titan is restricted to the two-stream approximation, is vertically homogeneous in its scattering properties, and is spectrally divided into one thermal and two solar channels. Between 13 and 33% of the total incident solar radiation is absorbed at the planetary surface, and the 30-60 ratio of violet to thermal IR absorption cross sections in the stratosphere leads to the large temperature inversion observed there. The spectrally integrated mass absorption coefficient at thermal wavelengths is approximately constant throughout the stratosphere, and approximately linear with pressure in the troposphere, implying the presence of a uniformly mixed aerosol in the stratosphere. There also appear to be two regions of enhanced opacity near 30 and 500 mbar.

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

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

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

  7. Cloud-radiative effects on implied oceanic energy transports as simulated by atmospheric general circulation models

    SciTech Connect

    Gleckler, P.J.; Randall, D.A.; Boer, G.

    1995-04-01

    This paper summarizes the ocean surface net energy flux simulated by fifteen atmospheric general circulation models constrained by realistically-varying sea surface temperatures and sea ice as part of the Atmospheric Model Intercomparison Project. In general, the simulated energy fluxes are within the very large observational uncertainties. However, the annual mean oceanic meridional heat transport that would be required to balance the simulated surface fluxes is shown to be critically sensitive to the radiative effects to clouds, to the extent that even the sign of the Southern Hemisphere ocean heat transport can be affected by the errors in simulated cloud-radiation interactions. It is suggested that improved treatment of cloud radiative effects should help in the development of coupled atmospheric-ocean general circulation models. 16 refs., 3 figs.

  8. Cloud-radiative effects on implied oceanic energy transport as simulated by atmospheric general circulation models

    NASA Technical Reports Server (NTRS)

    Gleckler, P. J.; Randall, D. A.; Boer, G.; Colman, R.; Dix, M.; Galin, V.; Helfand, M.; Kiehl, J.; Kitoh, A.; Lau, W.

    1995-01-01

    This paper summarizes the ocean surface net energy flux simulated by fifteen atmospheric general circulation models constrained by realistically-varying sea surface temperatures and sea ice as part of the Atmospheric Model Intercomparison Project. In general, the simulated energy fluxes are within the very large observational uncertainties. However, the annual mean oceanic meridional heat transport that would be required to balance the simulated surface fluxes is shown to be critically sensitive to the radiative effects of clouds, to the extent that even the sign of the Southern Hemisphere ocean heat transport can be affected by the errors in simulated cloud-radiation interactions. It is suggested that improved treatment of cloud radiative effects should help in the development of coupled atmosphere-ocean general circulation models.

  9. Atmospheric transmittance model for photosynthetically active radiation

    SciTech Connect

    Paulescu, Marius; Stefu, Nicoleta; Gravila, Paul; Paulescu, Eugenia; Boata, Remus; Pacurar, Angel; Mares, Oana; Pop, Nicolina; Calinoiu, Delia

    2013-11-13

    A parametric model of the atmospheric transmittance in the PAR band is presented. The model can be straightforwardly applied for calculating the beam, diffuse and global components of the PAR solar irradiance. The required inputs are: air pressure, ozone, water vapor and nitrogen dioxide column content, Ångström's turbidity coefficient and single scattering albedo. Comparison with other models and ground measured data shows a reasonable level of accuracy for this model, making it suitable for practical applications. From the computational point of view the calculus is condensed into simple algebra which is a noticeable advantage. For users interested in speed-intensive computation of the effective PAR solar irradiance, a PC program based on the parametric equations along with a user guide are available online at http://solar.physics.uvt.ro/srms.

  10. Infrared radiation in the mesosphere and lower thermosphere: energetic effects and coupling with lower atmosphere

    NASA Astrophysics Data System (ADS)

    Feofilov, Artem; Kutepov, Alexander; Rezac, Ladislav

    2013-04-01

    The translational degrees of freedom of atmospheric molecular and atomic gaseous compounds represent the heat reservoir. This reservoir obtains or loses energy due to a number of sources and sinks, among them heating and cooling related to various types of mass motions, redistribution of energy released in the course of various photochemical reactions (the translational energy, the chemical energy and the nascent electronic, vibration and rotational energy of the reaction products), and absorption and emission of the infrared (IR) radiation. In the latter case, one deals with interaction between matter and the IR radiative field, which, for the case of the mesosphere/lower thermosphere (MLT), includes the atmospheric radiation formed in these layers, the upwelling radiation from the ground and lower atmosphere, and, during daytime, the IR solar radiation. In this talk, we address the energetic effects of IR radiation in the MLT and its radiative coupling with lower atmosphere by analyzing the interaction between IR radiation and matter. In the MLT, this interaction is strongly affected by the situation when vibrational (and in its upper part also rotational) excitation of the molecules does not obey Boltzmann's law with the local kinetic temperature. As a result, the IR radiation emitted in these layers does not reflect the thermal state of matter. This situation is referred to as the breakdown of local thermodynamic equilibrium (LTE) for the vibrational (or rotational-vibrational) degrees of freedom. Detailed treatment of non-LTE plays a crucial role for estimating thermal effects of the IR radiation as well as for the diagnostics of space-based IR observations. We discuss the peculiarities of the non-LTE radiation formation in the IR bands of CO2, O3, and H2O molecules, estimate radiative cooling/heating rates for typical atmospheric scenarios, and analyze sensitivity of the MLT radiative energy balance to various mechanisms of populating/depopulating molecular

  11. VUV photochemistry simulation of planetary upper atmosphere using synchrotron radiation.

    PubMed

    Carrasco, Nathalie; Giuliani, Alexandre; Correia, Jean Jacques; Cernogora, Guy

    2013-07-01

    The coupling of a gas reactor, named APSIS, with a vacuum-ultraviolet (VUV) beamline at the SOLEIL synchrotron radiation facility, for a photochemistry study of gas mixtures, is reported. The reactor may be irradiated windowless with gas pressures up to hundreds of millibar, and thus allows the effect of energetic photons below 100 nm wavelength to be studied on possibly dense media. This set-up is perfectly suited to atmospheric photochemistry investigations, as illustrated by a preliminary report of a simulation of the upper atmospheric photochemistry of Titan, the largest satellite of Saturn. Titan's atmosphere is mainly composed of molecular nitrogen and methane. Solar VUV irradiation with wavelengths no longer than 100 nm on the top of the atmosphere enables the dissociation and ionization of nitrogen, involving a nitrogen chemistry specific to nitrogen-rich upper atmospheres.

  12. Hydraulic effects in a radiative atmosphere with ionization

    NASA Astrophysics Data System (ADS)

    Bhat, P.; Brandenburg, A.

    2016-03-01

    Context. In his 1978 paper, Eugene Parker postulated the need for hydraulic downward motion to explain magnetic flux concentrations at the solar surface. A similar process has also recently been seen in simplified (e.g., isothermal) models of flux concentrations from the negative effective magnetic pressure instability (NEMPI). Aims: We study the effects of partial ionization near the radiative surface on the formation of these magnetic flux concentrations. Methods: We first obtain one-dimensional (1D) equilibrium solutions using either a Kramers-like opacity or the H- opacity. The resulting atmospheres are then used as initial conditions in two-dimensional (2D) models where flows are driven by an imposed gradient force that resembles a localized negative pressure in the form of a blob. To isolate the effects of partial ionization and radiation, we ignore turbulence and convection. Results: Because of partial ionization, an unstable stratification always forms near the surface. We show that the extrema in the specific entropy profiles correspond to the extrema in the degree of ionization. In the 2D models without partial ionization, strong flux concentrations form just above the height where the blob is placed. Interestingly, in models with partial ionization, such flux concentrations always form at the surface well above the blob. This is due to the corresponding negative gradient in specific entropy. Owing to the absence of turbulence, the downflows reach transonic speeds. Conclusions: We demonstrate that, together with density stratification, the imposed source of negative pressure drives the formation of flux concentrations. We find that the inclusion of partial ionization affects the entropy profile dramatically, causing strong flux concentrations to form closer to the surface. We speculate that turbulence effects are needed to limit the strength of flux concentrations and homogenize the specific entropy to a stratification that is close to marginal.

  13. Satellite data sets for the atmospheric radiation measurement (ARM) program

    SciTech Connect

    Shi, L.; Bernstein, R.L.

    1996-04-01

    This abstract describes the type of data obtained from satellite measurements in the Atmospheric Radiation Measurement (ARM) program. The data sets have been widely used by the ARM team to derive cloud-top altitude, cloud cover, snow and ice cover, surface temperature, water vapor, and wind, vertical profiles of temperature, and continuoous observations of weather needed to track and predict severe weather.

  14. Science Plan for the Atmospheric Radiation Measurement Program (ARM)

    SciTech Connect

    1996-02-01

    The purpose of this Atmospheric Radiation Measurement (ARM) Science Plan is to articulate the scientific issues driving the ARM Program, and to relate them to DOE`s programmatic objectives for ARM, based on the experience and scientific progress gained over the past five years. ARM programmatic objectives are to: (1) Relate observed radiative fluxes and radiances in the atmosphere, spectrally resolved and as a function of position and time, to the temperature and composition of the atmosphere, specifically including water vapor and clouds, and to surface properties, and sample sufficient variety of situations so as to span a wide range of climatologically relevant possibilities; (2) develop and test parameterizations that can be used to accurately predict the radiative properties and to model the radiative interactions involving water vapor and clouds within the atmosphere, with the objective of incorporating these parameterizations into general circulation models. The primary observational methods remote sending and other observations at the surface, particularly remote sensing of clouds, water vapor and aerosols.

  15. Atmospheric radiation measurement program facilities newsletter, September 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-10-02

    This Atmospheric radiation measurement program facilities newsletter covers the following topics: The Raman lidar at the SGP central facility is receiving upgrades to its environmental controls; The instrument tower at Okmulgee State Park is receiving upgrades to prevent Turkey Vultures from roosting on the booms.

  16. Highly physical penumbra solar radiation pressure modeling with atmospheric effects

    NASA Astrophysics Data System (ADS)

    Robertson, Robert; Flury, Jakob; Bandikova, Tamara; Schilling, Manuel

    2015-10-01

    We present a new method for highly physical solar radiation pressure (SRP) modeling in Earth's penumbra. The fundamental geometry and approach mirrors past work, where the solar radiation field is modeled using a number of light rays, rather than treating the Sun as a single point source. However, we aim to clarify this approach, simplify its implementation, and model previously overlooked factors. The complex geometries involved in modeling penumbra solar radiation fields are described in a more intuitive and complete way to simplify implementation. Atmospheric effects are tabulated to significantly reduce computational cost. We present new, more efficient and accurate approaches to modeling atmospheric effects which allow us to consider the high spatial and temporal variability in lower atmospheric conditions. Modeled penumbra SRP accelerations for the Gravity Recovery and Climate Experiment (GRACE) satellites are compared to the sub-nm/s2 precision GRACE accelerometer data. Comparisons to accelerometer data and a traditional penumbra SRP model illustrate the improved accuracy which our methods provide. Sensitivity analyses illustrate the significance of various atmospheric parameters and modeled effects on penumbra SRP. While this model is more complex than a traditional penumbra SRP model, we demonstrate its utility and propose that a highly physical model which considers atmospheric effects should be the basis for any simplified approach to penumbra SRP modeling.

  17. Atmospheric Radiation Measurement Program facilities newsletter, April 2000

    SciTech Connect

    Sisterson, D. L.

    2000-05-05

    This issue of the Atmospheric Radiation Measurement Program (ARM Program) monthly newsletter is about the ARM Program goal to improve scientific understanding of the interactions of sunlight (solar radiation) with the atmosphere, then incorporate this understanding into computer models of climate change. To model climate accurately all around the globe, a variety of data must be collected from many locations on Earth. For its Cloud and Radiation Testbed (CART) sites, ARM chose locations in the US Southern Great Plains, the North Slope of Alaska, and the Tropical Western Pacific Ocean to represent different climate types around the world. In this newsletter they consider the North Slope of Alaska site, with locations at Barrow and Atqasuk, Alaska.

  18. Radiative transfer in nonuniformly refracting layered media: atmosphere-ocean system.

    PubMed

    Jin, Z; Stamnes, K

    1994-01-20

    We have applied the discrete-ordinate method to solve the radiative-transfer problem pertaining to a system consisting of two strata with different indices of refraction. The refraction and reflection at the interface are taken into account. The relevant changes (as compared with the standard problem with a constant index of refraction throughout the medium) in formulation and solution of the radiative-transfer equation, including the proper application of interface and boundary conditions, are described. Appropriate quadrature points (streams) and weights are chosen for the interface-continuity relations. Examples of radiative transfer in the coupled atmosphere-ocean system are provided. To take into account the region of total reflection in the ocean, additional angular quadrature points are required, compared with those used in the atmosphere and in the refractive region of the ocean that communicates directly with the atmosphere. To verify the model we have tested for energy conservation. We also discuss the effect of the number of streams assigned to the refractive region and the total reflecting region on the convergence. Our results show that the change in the index of refraction between the two strata significantly affects the radiation field. The radiative-transfer model we present is designed for application to the atmosphere-ocean system, but it can be applied to other systems that need to consider the change in the index of refraction between two strata. PMID:20862035

  19. Influence of atmospheric relative humidity on ultraviolet flux and aerosol direct radiative forcing: Observation and simulation

    NASA Astrophysics Data System (ADS)

    Xia, Dong; Chen, Ling; Chen, Huizhong; Luo, Xuyu; Deng, Tao

    2016-08-01

    The atmospheric aerosols can absorb moisture from the environment due to their hydrophilicity and thus affect atmospheric radiation fluxes. In this article, the ultraviolet radiation and relative humidity (RH) data from ground observations and a radiative transfer model were used to examine the influence of RH on ultraviolet radiation flux and aerosol direct radiative forcing under the clear-sky conditions. The results show that RH has a significant influence on ultraviolet radiation because of aerosol hygroscopicity. The relationship between attenuation rate and RH can be fitted logarithmically and all of the R2 of the 4 sets of samples are high, i.e. 0.87, 0.96, 0.9, and 0.9, respectively. When the RH is 60%, 70%, 80% and 90%, the mean aerosol direct radiative forcing in ultraviolet is -4.22W m-2, -4.5W m-2, -4.82W m-2 and -5.4W m-2, respectively. For the selected polluted air samples the growth factor for computing aerosol direct radiative forcing in the ultraviolet for the RH of 80% varies from 1.19 to 1.53, with an average of 1.31.

  20. Application of 3-D radiative transfer theory to atmospheric correction of land surface images

    NASA Technical Reports Server (NTRS)

    Diner, D. J.; Martonchik, J. V.; Danielson, E. D.; Bruegge, C. J.

    1988-01-01

    Three dimensional radiative transfer theory was applied to computation of atmospheric effects on remotely sensed imagery. The atmospheric correction algorithm derived is used to estimate aerosol opacity.

  1. Carbonaceous aerosols influencing atmospheric radiation: Black and organic carbon

    SciTech Connect

    Penner, J.E.

    1994-09-01

    Carbonaceous particles in the atmosphere may both scatter and absorb solar radiation. The fraction associated with the absorbing component is generally referred to as black carbon (BC) and is mainly produced from incomplete combustion processes. The fraction associated with condensed organic compounds is generally referred to as organic carbon (OC) or organic matter and is mainly scattering. Absorption of solar radiation by carbonaceous aerosols may heat the atmosphere, thereby altering the vertical temperature profile, while scattering of solar radiation may lead to a net cooling of the atmosphere/ocean system. Carbonaceous aerosols may also enhance the concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the fine particle (D < 2.5 {mu}m) source rates of both OC and BC. The source rates for anthropogenic organic aerosols may be as large as the source rates for anthropogenic sulfate aerosols, suggesting a similar magnitude of direct forcing of climate. The role of BC in decreasing the amount of reflected solar radiation by OC and sulfates is discussed. The total estimated forcing depends on the source estimates for organic and black carbon aerosols which are highly uncertain. The role of organic aerosols acting as cloud condensation nuclei (CCN) is also described.

  2. Processes linking the hydrological cycle and the atmospheric radiative budget

    NASA Astrophysics Data System (ADS)

    Fueglistaler, Stephan; Dinh, Tra

    2016-04-01

    We study the response of the strength of the global hydrological cycle to changes in carbon dioxide (CO2) using the HiRAM General Circulation Model developed at the Geophysical Fluid Dynamics Laboratory (GFDL), with the objective to better connect the well-known energetic constraints to physical processes. We find that idealized model setups using a global slab ocean and annual mean insolation give similar scalings as coupled atmosphere-ocean models with realistic land and topography. Using the surface temperatures from the slab ocean runs, we analyse the response in the atmospheric state and hydrological cycle separately for a change in CO2 (but fixed surface temperature), and for a change in surface temperature (but fixed CO2). The former perturbation is also referred to as the "fast" response, whereas the latter is commonly used to diagnose a model's climate sensitivity. As expected from the perspective of the atmospheric radiative budget, an increase in CO2 at fixed surface temperature decreases the strength of the hydrological cycle, and an increase in surface temperature increases the strength of the hydrological cycle. However, the physical processes that connect the atmospheric radiative energy budget to the sensible and latent heat fluxes at the surface remain not well understood. The responses to the two perturbations are linearly additive, and we find that the experiment with fixed surface temperature and changes in CO2 is of great relevance to understanding the total response. This result points to the importance of local radiative heating rate changes rather than just the net atmospheric radiative loss of energy. Although larger in magnitude, the response to changes in surface temperature is dominated by the temperature dependence of the water vapor pressure, but in both cases changes in near-surface relative humidity are very important.

  3. Atmospheric general circulation and its low frequency variance - Radiative influences

    NASA Technical Reports Server (NTRS)

    Ramanathan, V.

    1987-01-01

    The possible effects of radiation on the evolution of the atmosphere on time scales ranging from about a week to about 90 days are examined with reference to the available observational and modeling studies. The clear-sky and cloud radiative processes are shown to exert significant vertical, latitudinal, and longitudinal gradients in the diabatic heating within the troposphere and the stratosphere. The meridional heating gradient, which drives the general circulation, is altered significantly by clouds. The major conclusion of the study is that the observed negative anomalies in the outgoing IR radiation following intense warm episodes of tropicl sea-surface temperature (El Nino) are indeed anomalies in the cloud-radiative forcing.

  4. Detection of atmospheric Cherenkov radiation using solar heliostat mirrors

    NASA Astrophysics Data System (ADS)

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

    1996-10-01

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

  5. Albert Gockel, a pioneer in atmospheric electricity and cosmic radiation

    NASA Astrophysics Data System (ADS)

    Lacki, Jan

    2014-01-01

    At the beginning of the 20th century, the community of investigators of atmospheric electricity included scholars from most (Western) European countries and even beyond. If Victor Hess is deservedly remembered as the discoverer of cosmic rays, his achievements was made possible by the work of close predecessors whose contributions went with time almost forgotten. One of the most noteworthy was Albert Gockel (1860-1927) from Freiburg (CH) University. I want to discuss Gockel's achievements in atmospheric electricity and in particular his substantial contribution to the study of ionizing radiation which led to the discovery of its cosmic origin.

  6. The Dynamics of the Atmospheric Radiation Environment at Aviation Altitudes

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, Epaminondas G.

    2004-01-01

    Single Event Effects vulnerability of on-board computers that regulate the: navigational, flight control, communication, and life support systems has become an issue in advanced modern aircraft, especially those that may be equipped with new technology devices in terabit memory banks (low voltage, nanometer feature size, gigabit integration). To address this concern, radiation spectrometers need to fly continually on a multitude of carriers over long periods of time so as to accumulate sufficient information that will broaden our understanding of the very dynamic and complex nature of the atmospheric radiation environment regarding: composition, spectral distribution, intensity, temporal variation, and spatial variation.

  7. How Do Coronal Hole Storms Affect the Upper Atmosphere?

    NASA Astrophysics Data System (ADS)

    Mannucci, A. J.; Tsurutani, B. T.; Solomon, S. C.; Verkhoglyadova, O. P.; Thayer, J. P.

    2012-02-01

    The solar cycle, often described as an increase and decrease of solar activity with a period of about 11 years, can strongly affect Earth's thermosphere and ionosphere. Although the longest direct record of solar activity is based on sunspot number, a more quantifiable parameter is solar irradiance at extreme ultraviolet (EUV) wavelengths, which varies by more than a factor of 3 over the sunspot cycle. To first order, upper atmospheric variation is a result of changes in ionizing fluxes at EUV wavelengths. As the solar cycle passes its EUV peak and approaches minimum, the number of solar active regions declines, leading to a reduction and then a near absence of coronal mass ejections (CMEs)—episodic events of high-energy bursts of solar plasma that cause geomagnetic storms at Earth. During the solar cycle's declining phase, coronal holes begin to occupy lower latitudes on the solar surface and fall in line with the ecliptic plane.

  8. Atmospheric Radiation Measurement program (ARM) -- Summer 1995 review

    SciTech Connect

    MacDonald, G.; Ruderman, M.; Treiman, S.

    1995-10-01

    ARM is a highly focused program designed to improve the understanding of the transport of infrared and solar radiation through the atmosphere. The program pays particular attention to the interaction of radiation with the three phases of water. The goals of ARM are usually articulated in terms of improvements in climate models. The authors agree that ARM can indeed make significant contributions to the understanding of climate change. In addition the authors believe that the results of the program will have wide applicability to a broad range of problems, including more accurate short-term and seasonal weather forecasting. This report examines the issues of anomalous atmospheric absorption and makes recommendations concerning future directions for the ARM program.

  9. Atmospheric Radiation Measurement Program facilities newsletter, July 2001.

    SciTech Connect

    Holdridge, D. J.

    2001-07-23

    Global Warming and Methane--Global warming, an increase in Earth's near-surface temperature, is believed to result from the buildup of what scientists refer to as ''greenhouse gases.'' These gases include water vapor, carbon dioxide, methane, nitrous oxide, ozone, perfluorocarbons, hydrofluoro-carbons, and sulfur hexafluoride. Greenhouse gases can absorb outgoing infrared (heat) radiation and re-emit it back to Earth, warming the surface. Thus, these gases act like the glass of a greenhouse enclosure, trapping infrared radiation inside and warming the space. One of the more important greenhouse gases is the naturally occurring hydrocarbon methane. Methane, a primary component of natural gas, is the second most important contributor to the greenhouse effect (after carbon dioxide). Natural sources of methane include wetlands, fossil sources, termites, oceans, fresh-waters, and non-wetland soils. Methane is also produced by human-related (or anthropogenic) activities such as fossil fuel production, coal mining, rice cultivation, biomass burning, water treatment facilities, waste management operations and landfills, and domesticated livestock operations (Figure 1). These anthropogenic activities account for approximately 70% of the methane emissions to the atmosphere. Methane is removed naturally from the atmosphere in three ways. These methods, commonly referred to as sinks, are oxidation by chemical reaction with tropospheric hydroxyl ion, oxidation within the stratosphere, and microbial uptake by soils. In spite of their important role in removing excess methane from the atmosphere, the sinks cannot keep up with global methane production. Methane concentrations in the atmosphere have increased by 145% since 1800. Increases in atmospheric methane roughly parallel world population growth, pointing to anthropogenic sources as the cause (Figure 2). Increases in the methane concentration reduce Earth's natural cooling efficiency by trapping more of the outgoing

  10. A fast radiative transfer model for SSMIS upper atmosphere sounding channels

    NASA Astrophysics Data System (ADS)

    Han, Yong; Weng, Fuzhong; Liu, Quanhua; van Delst, Paul

    2007-06-01

    Special Sensor Microwave Imager/Sounder (SSMIS) on board the Defense Meteorology Satellite Program (DMSP) F-16 satellite probes the atmospheric temperature from surface to 100 km. SSMIS channels 19-22 are significantly affected by Zeeman splitting, which is dependent on the Earth's magnetic field. Thus, in satellite data assimilation or retrieval systems, SSMIS brightness temperatures and their Jacobians (or gradient with respect to temperature) must be computed with a fast radiative transfer (RT) scheme that takes into account the Zeeman-splitting effect. In this study, an averaged transmittance within the channel frequency passbands is parameterized and predicted with atmospheric temperature, geomagnetic field strength, and the angle between the geomagnetic field vector and the electromagnetic wave propagation direction. The coefficients of predictors are trained with a line-by-line (LBL) radiative transfer model that accurately computes the monochromatic transmittances at fine frequency steps within each passband. The new radiative transfer scheme is compared to the results from the line-by-line model for the dependent and independent data sets. It is shown that the differences between the two models are well below the instrument noise levels but the new scheme is much faster. It is also shown that the SSMIS measurements agree well with the simulations that are based on the atmospheric profiles from the sounding of the atmosphere using broadband emission radiometry (SABER) on the Thermosphere-lonosphere-Mesosphere Energetics and Dynamics satellite and the COSPAR international reference atmosphere (CIRA) model.

  11. Thick galactic cosmic radiation shielding using atmospheric data

    NASA Astrophysics Data System (ADS)

    Youngquist, Robert C.; Nurge, Mark A.; Starr, Stanley O.; Koontz, Steven L.

    2014-01-01

    NASA is concerned with protecting astronauts from the effects of galactic cosmic radiation and has expended substantial effort in the development of computer models to predict the shielding obtained from various materials. However, these models were only developed for shields up to about 120 g/cm2 in mass thickness and have predicted that shields of this mass thickness are insufficient to provide adequate protection for extended deep space flights. Consequently, effort is underway to extend the range of these models to thicker shields and experimental data is required to help confirm the resulting code. In this paper empirically obtained effective dose measurements from aircraft flights in the atmosphere are used to obtain the radiation shielding function of the Earth's atmosphere, a very thick, i.e. high mass, shield. Obtaining this result required solving an inverse problem and the method for solving it is presented. The results are shown to be in agreement with current code in the ranges where they overlap. These results are then checked and used to predict the radiation dosage under thick shields such as planetary regolith and the atmosphere of Venus.

  12. Thick Galactic Cosmic Radiation Shielding Using Atmospheric Data

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.; Nurge, Mark A.; Starr, Stanley O.; Koontz, Steven L.

    2013-01-01

    NASA is concerned with protecting astronauts from the effects of galactic cosmic radiation and has expended substantial effort in the development of computer models to predict the shielding obtained from various materials. However, these models were only developed for shields up to about 120 g!cm2 in thickness and have predicted that shields of this thickness are insufficient to provide adequate protection for extended deep space flights. Consequently, effort is underway to extend the range of these models to thicker shields and experimental data is required to help confirm the resulting code. In this paper empirically obtained effective dose measurements from aircraft flights in the atmosphere are used to obtain the radiation shielding function of the earth's atmosphere, a very thick shield. Obtaining this result required solving an inverse problem and the method for solving it is presented. The results are shown to be in agreement with current code in the ranges where they overlap. These results are then checked and used to predict the radiation dosage under thick shields such as planetary regolith and the atmosphere of Venus.

  13. 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.

  14. Preliminary design for Arctic atmospheric radiative transfer experiments

    NASA Astrophysics Data System (ADS)

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

    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.

  15. Atmospheric aerosol variability in Estonia calculated from solar radiation measurements

    NASA Astrophysics Data System (ADS)

    Russak, Viivi

    1996-10-01

    Direct solar radiation data obtained during 1955 1994 at the Tõravere Actinometric Station (Estonia) have been used to study the long-term variations of the atmospheric aerosol. In a linear approximation, the optical thickness of atmospheric aerosol averaged over months from April to August has increased by 73% at Tõravere during the last 40years. The aerosol loading of the atmosphere depends on wind direction, the southern and southeastern winds being the main carriers of aerosol. During the last decade, the increase in the optical thickness of aerosol in the case of W-, NW- and N-winds has slowed down. This is most likely caused by a reduction in the SO2 emission in Western and Central Europe as well as in Finland. In April, the advection of aerosol is greatest from the NE-direction. We suppose that this effect points to the possibility of aerosol transfer to Estonia through the Arctic regions.

  16. Cloud-radiative effects on implied oceanic energy transports as simulated by atmospheric general circulation models

    SciTech Connect

    Gleckler, P.J.; Randall, D.A.; Boer, G.

    1994-03-01

    This paper reports on energy fluxes across the surface of the ocean as simulated by fifteen atmospheric general circulation models in which ocean surface temperatures and sea-ice boundaries are prescribed. The oceanic meridional energy transport that would be required to balance these surface fluxes is computed, and is shown to be critically sensitive to the radiative effects of clouds, to the extent that even the sign of the Southern Hemisphere ocean energy transport can be affected by the errors in simulated cloud-radiation interactions.

  17. Measurement of microwave radiation from electron beam in the atmosphere

    NASA Astrophysics Data System (ADS)

    Ohta, I. S.; Akimune, H.; Fukushima, M.; Ikeda, D.; Inome, Y.; Matthews, J. N.; Ogio, S.; Sagawa, H.; Sako, T.; Shibata, T.; Yamamoto, T.

    2016-02-01

    We report the use of an electron light source (ELS) located at the Telescope Array Observatory in Utah, USA, to measure the isotropic microwave radiation from air showers. To simulate extensive air showers, the ELS emits an electron beam into the atmosphere and a parabola antenna system for the satellite communication is used to measure the microwave radiation from the electron beam. Based on this measurement, an upper limit on the intensity of a 12.5 GHz microwave radiation at 0.5 m from a 1018 eV air shower was estimated to be 3.96×10-16 W m-2 Hz-1 with a 95% confidence level.

  18. Effects of cirrus composition on atmospheric radiation budgets

    NASA Technical Reports Server (NTRS)

    Kinne, Stefan; Liou, Kuo-Nan

    1988-01-01

    A radiative transfer model that can be used to determine the change in solar and infrared fluxes caused by variations in the composition of cirrus clouds was used to investigate the importance of particle size and shape on the radiation budget of the Earth-atmosphere system. Even though the cloud optical thickness dominates the radiative properties of ice clouds, the particle size and nonsphericity of ice crystals are also important in calculations of the transfer of near-IR solar wavelengths. Results show that, for a given optical thickness, ice clouds composed of larger particles would produce larger greenhouse effects than those composed of smaller particles. Moreover, spherical particles with equivalent surface areas, frequently used for ice crystal clouds, would lead to an overestimation of the greenhouse effect.

  19. Atmospheric radiation measurement program facilities newsletter, August 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-08-29

    ARM in Australia--The Atmospheric Radiation Measurement (ARM) Program of the U.S. Department of Energy (DOE) has launched its newest Atmospheric Radiation and Cloud Station (ARCS) in Darwin, Australia. This is the fifth research site established since ARM Program inception in 1989. The new Darwin site and two other ARCS sites--on Manus Island and the island of Nauru--are in the Tropical Western Pacific region. The North American sites in the U.S. Southern Great Plains and on the North Slope of Alaska represent two different climate regions. A goal of the ARM Program is to improve understanding of (1) the ways clouds and atmospheric moisture interact with solar radiation and (2) the effects of these interactions on both a local and global climate. Years of collected data are being used to improve computer climate models so that their predictions are more accurate. The new Darwin site is at the Darwin International Airport, adjacent to the Darwin Airport Meteorological Office. The site features state-of-the-art instrumentation used to measure solar radiation and surface radiation balance; cloud parameters; and standard meteorological variables such as temperature, wind speed and direction, atmospheric moisture, precipitation rates, and barometric pressure. A data management system (DMS) consisting of two computer workstations collects, stores, processes, and backs up data from each of the ARCS instruments. Data are transmitted via the Internet to the United States for further processing and archiving with data from the other ARM sites. All ARM data are freely available via the Internet to the public and the worldwide scientific community (http://www.arm.gov/). Operational since April 2002, the Darwin site was officially dedicated on July 30, 2002, by dignitaries from both the United States and Australia. The site is a collaborative effort between DOE and the Australian Bureau of Meteorology's Special Services Unit--the equivalent of the U.S. National Weather Service

  20. Remote sensing strategy at the first Atmospheric Radiation Measurement field site

    SciTech Connect

    Wesely, M.L.; Griffin, J.W.

    1994-07-01

    The Atmospheric Radiation Measurement (ARM) Program was initiated in 1990 by the US Department of Energy to improve climate model simulations of radiative energy transport and cloud formation, maintenance, and dissipation. ARM stresses the modeling of phenomena occurring at subgrid scales in general circulation models (GCMs). Measurements to support the modeling research will be made at three primary locations. The central facility, the primary location at the Southern Great Plains (SGP) site for study of radiative transfer, uses ground-based remote sensing instrumentation to observe radiation and the atmospheric properties that affect it. Remote sensing instruments and balloon-borne sounding systems installed at several boundary facilities on the perimeter of the overall Cloud and Radiation Testbed (CART) site evaluate vertical profiles of wind, temperature, and humidity. These observations are needed to run single-column models derived from GCMs for a single grid square with an area equivalent to the overall CART area. Observations of local meteorological conditions, air-surface exchange, and solar and infrared radiation at up to 23 extended facilities scattered throughout the CART site provide the surface boundary information needed in the single-column models. Finally, auxiliary facilities at the central facility and at a few locations within 10 km of the central facility will contain whole-sky imaging systems to map cloud characteristics. The purpose of this presentation is to describe the strategy used to obtain remote sensing instrumentation for continuous operation at the central facility.

  1. Theory of Radiation Transfer in Neutron Star Atmospheres

    NASA Technical Reports Server (NTRS)

    Zavlin, Vyacheslav

    2006-01-01

    The possibility for direct investigation of thermal emission from isolated neutron stars opened about a quarter of century ago with the launch of the first X-ray observatories Einstein and EXOSAT stimulated developing models of the neutron star surface radiation which began at the end of 80's. Confronting observational data with theoretical models of thermal emission allows one to infer the surface temperatures, magnetic fields, chemical composition, and neutron star masses and radii. This information, supplemented with the model equations of state and neutron star cooling models, provides an opportunity to understand the fundamental properties of the superdense matter in the stars' interiors. Almost all available models are based on the assumption that thermal radiation emitted by a neutron star is formed in the superficial star's layers--atmosphere. The neutron star atmospheres are very different from those of usual stars due to the immense gravity and huge magnetic fields. In this presentation we review the current status of the neutron star atmosphere modeling, present most important results, discuss problems and possible future developments.

  2. Design of a differential radiometer for atmospheric radiative flux measurements

    SciTech Connect

    LaDelfe, P.C.; Weber, P.G.; Rodriguez, C.W.

    1994-11-01

    The Hemispherical Optimized NEt Radiometer (HONER) is an instrument under development at the Los Alamos National Laboratory for deployment on an unmanned aerospace vehicle as part of the Atmospheric Radiation Measurements (ARM/UAV) program. HONER is a differential radiometer which will measure the difference between the total upwelling and downwelling fluxes and is intended to provide a means of measuring the atmospheric radiative flux divergence. Unlike existing instruments which measure the upwelling and downwelling fluxes separately, HONER will achieve an optical difference by chopping the two fluxes alternately onto a common pyroelectric detector. HONER will provide data resolved into two spectral bands; one covering the solar dominated region from less than 0.4 micrometer to approximately 4.5 micrometers and the other covering the region from approximately 4.5 micrometers to greater than 50 micrometers, dominated by thermal radiation. The means of separating the spectral regions guarantees seamless summation to calculate the total flux. The fields-of-view are near-hemispherical, upward and downward. The instrument can be converted, in flight, from the differential mode to absolute mode, measuring the upwelling and downwelling fluxes separately and simultaneously. The instrument also features continuous calibration from on-board sources. We will describe the design and operation of the sensor head and the on-board reference sources as well as the means of deployment.

  3. Monitoring precipitation and lightning via changes in atmospheric gamma radiation

    SciTech Connect

    Greenfield, M.B.; Domondon, A.; Tsuchiya, S.; Tomiyama, G.

    2003-08-26

    Atmospheric {gamma}-radiation has been measured since 1999 and recently at three elevations 220m from the first site to ascertain position dependency and optimal elevation for observing {gamma}-rays from radon and radon-progeny found in precipitation. Radiation from time-independent and diurnal components was minimized in order to ascertain the reliability, accuracy and practicality of determining precipitation rates from correlated {gamma}-rates. Data taken with 4-12.9cm3 NaI detectors at elevations above ground of 9.91, 14.2, 15.7, and 21.4 m were fit with a model assuming a surface and/or volume deposition of radon progeny on/in water droplets during precipitation which predicts {gamma} -ray rates proportional to the 2/5 and/or 3/5 power of rain rates, respectively. With mostly surface deposition and age corrections for radon progeny, the correlation coefficients improved with elevation and reached a maximum at 0.95 around 20m. Atmospheric {gamma} radiation enables monitoring precipitation rates to 0.3 mm/h with time resolution limited only by counting statistics. High {gamma}-ray rates, decreasing with 40-minute half-life following lightning may be indirectly due to ions accelerated in electric field.

  4. NONLINEAR EVOLUTION OF RAYLEIGH-TAYLOR INSTABILITY IN A RADIATION-SUPPORTED ATMOSPHERE

    SciTech Connect

    Jiang, Yan-Fei; Stone, James M.; Davis, Shane W.

    2013-02-15

    The nonlinear regime of Rayleigh-Taylor instability (RTI) in a radiation supported atmosphere, consisting of two uniform fluids with different densities, is studied numerically. We perform simulations using our recently developed numerical algorithm for multi-dimensional radiation hydrodynamics based on a variable Eddington tensor (VET) as implemented in Athena, focusing on the regime where scattering opacity greatly exceeds absorption opacity. We find that the radiation field can reduce the growth and mixing rate of RTI, but this reduction is only significant when radiation pressure significantly exceeds gas pressure. Small-scale structures are also suppressed in this case. In the nonlinear regime, dense fingers sink faster than rarefied bubbles can rise, leading to asymmetric structures about the interface. By comparing the calculations that use a VET versus the Eddington approximation, we demonstrate that anisotropy in the radiation field can affect the nonlinear development of RTI significantly. We also examine the disruption of a shell of cold gas being accelerated by strong radiation pressure, motivated by models of radiation driven outflows in ultraluminous infrared galaxies. We find that when the growth timescale of RTI is smaller than acceleration timescale, the amount of gas that would be pushed away by the radiation field is reduced due to RTI.

  5. Nonlinear Evolution of Rayleigh-Taylor Instability in a Radiation-supported Atmosphere

    NASA Astrophysics Data System (ADS)

    Jiang, Yan-Fei; Davis, Shane W.; Stone, James M.

    2013-02-01

    The nonlinear regime of Rayleigh-Taylor instability (RTI) in a radiation supported atmosphere, consisting of two uniform fluids with different densities, is studied numerically. We perform simulations using our recently developed numerical algorithm for multi-dimensional radiation hydrodynamics based on a variable Eddington tensor (VET) as implemented in Athena, focusing on the regime where scattering opacity greatly exceeds absorption opacity. We find that the radiation field can reduce the growth and mixing rate of RTI, but this reduction is only significant when radiation pressure significantly exceeds gas pressure. Small-scale structures are also suppressed in this case. In the nonlinear regime, dense fingers sink faster than rarefied bubbles can rise, leading to asymmetric structures about the interface. By comparing the calculations that use a VET versus the Eddington approximation, we demonstrate that anisotropy in the radiation field can affect the nonlinear development of RTI significantly. We also examine the disruption of a shell of cold gas being accelerated by strong radiation pressure, motivated by models of radiation driven outflows in ultraluminous infrared galaxies. We find that when the growth timescale of RTI is smaller than acceleration timescale, the amount of gas that would be pushed away by the radiation field is reduced due to RTI.

  6. Atmospheric, Ionospheric, and Energetic Radiation Environments of Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Cooper, J. F.; Kollmann, P.; Sittler, E. C., Jr.; Johnson, R. E.; Sturner, S. J.

    2015-12-01

    Planetary magnetospheric and high-energy cosmic ray interactions with Saturn's rings were first explored in-situ during the Pioneer 11 flyby in 1979. The following Voyager flybys produced a wealth of new information on ring structure and mass, and on spatial structure of the radiation belts beyond the main rings. Next came the Cassini Orbiter flyover of the rings during Saturn Orbital Insertion in 2004 with the first in-situ measurements of the ring atmosphere and plasma ionosphere. Cassini has since fully explored the radiation belt and magnetospheric plasma region beyond the main rings, discovering how Enceladus acts as a source of water group neutrals and water ions for the ion plasma. But do the main rings also substantially contribute by UV photolysis to water group plasma (H+, O+, OH+, H2O+, H3O+, O2+) and neutrals inwards from Enceladus? More massive rings, than earlier inferred from Pioneer 11 and Voyager observations, would further contribute by bulk ring ice radiolysis from interactions of galactic cosmic ray particles. Products of these interactions include neutron-decay proton and electron injection into the radiation belts beyond the main rings. How does radiolysis from moon and ring sweeping of the radiation belt particles compare with direct gas and plasma sources from the main rings and Enceladus? Can the magnetospheric ion and electron populations reasonably be accounted for by the sum of the ring-neutron-decay and outer magnetospheric inputs? Pioneer 11 made the deepest radial penetration into the C-ring, next followed by Cassini SOI. What might Cassini's higher-inclination proximal orbits reveal about the atmospheric, ionospheric, and energetic radiation environments in the D-ring and the proximal gap region? Recent modeling predicts a lower-intensity innermost radiation belt extending from the gap to the inner D-ring. Other remaining questions include the lifetimes of narrow and diffuse dust rings with respect to plasma and energetic particle

  7. The effects of atmospheric chemistry on radiation budget in the Community Earth Systems Model

    NASA Astrophysics Data System (ADS)

    Choi, Y.; Czader, B.; Diao, L.; Rodriguez, J.; Jeong, G.

    2013-12-01

    The Community Earth Systems Model (CESM)-Whole Atmosphere Community Climate Model (WACCM) simulations were performed to study the impact of atmospheric chemistry on the radiation budget over the surface within a weather prediction time scale. The secondary goal is to get a simplified and optimized chemistry module for the short time period. Three different chemistry modules were utilized to represent tropospheric and stratospheric chemistry, which differ in how their reactions and species are represented: (1) simplified tropospheric and stratospheric chemistry (approximately 30 species), (2) simplified tropospheric chemistry and comprehensive stratospheric chemistry from the Model of Ozone and Related Chemical Tracers, version 3 (MOZART-3, approximately 60 species), and (3) comprehensive tropospheric and stratospheric chemistry (MOZART-4, approximately 120 species). Our results indicate the different details in chemistry treatment from these model components affect the surface temperature and impact the radiation budget.

  8. Elevated atmospheric carbon dioxide in agroecosystems affects groundwater quality

    SciTech Connect

    Torbert, H.A.; Prior, S.A.; Rogers, H.H.; Schlesinger, W.H.; Mullins, G.L.; Runion, G.B.

    1996-07-01

    Increasing atmospheric carbon dioxide (CO{sub 2}) concentration has led to concerns about global changes to the environment. One area of global change that has not been addressed is the effect of elevated atmospheric CO{sub 2} on groundwater quality below agroecosystems. Elevated CO{sub 2} concentration alterations of plant growth and C/N ratios may modify C and N cycling in soil and affect nitrate (NO{sub 3}{sup {minus}}) leaching to groundwater. This study was conducted to examine the effects of a legume (soybean [Glycine max (L.) Merr.]) and a nonlegume (grain sorghum [Sorghum bicolor (L.) Moench]) CO{sub 2}-enriched agroecosystems on NO{sub 3}{sup {minus}} movement below the root zone in a Blanton loamy sand (loamy siliceous, thermic, Grossarenic Paleudults). The study was a split-plot design replicated three times with plant species (soybean and grain sorghum) as the main plots and CO{sub 2} concentration ({approximately}360 and {approximately}720 {mu}L L{sup {minus}1} CO{sub 2}) as subplots using open-top field chambers. Fertilizer application was made with {sup 15}N-depleted NH{sub 4}NO{sub 3} to act as a fertilizer tracer. Soil solution samples were collected weekly at 90-cm depth for a 2-yr period and monitored for NO{sub 3}{sup {minus}}-N concentrations. Isotope analysis of soil solution indicated that the decomposition of organic matter was the primary source of No{sub 3}{sup {minus}}-N in soil solution below the root zone through most of the monitoring period. Significant differences were observed for NO{sub 3}{sup {minus}}-N concentrations between soybean and grain sorghum, with soybean having the higher NO{sub 3}{sup {minus}}-N concentration. Elevated CO{sub 2} increased total dry weight, total N content, and C/N ratio of residue returned to soil in both years. Elevated CO{sub 2} significantly decreased NO{sub 3}{sup {minus}}-N concentrations below the root zone in both soybean and grain sorghum. 37 refs., 2 figs., 2 tabs.

  9. Radiative transfer in an atmosphere-ocean system.

    PubMed

    Plass, G N; Kattawar, G W

    1969-02-01

    The radiation field for an atmosphere-ocean system is calculated by a Monte Carlo method. In the atmosphere, both Rayleigh scattering by the molecules and Mie scattering by the aerosols and water droplets, when present, as well as molecular and aerosol absorption are included in the model. Similarly, in the ocean, both Rayleigh scattering by the water molecules and Mie scattering by the hydrosols as well as absorption by the water molecules and hydrosols are considered. Separate scattering functions are calculated from the Mie theory for the water droplets in clouds, the aerosols, and the hydrosols with an appropriate and different size distribution in each case. The photon path is followed accurately in three dimensions with new scattering angles determined from the appropriate scattering function including the strong forward scattering peak. Both the reflected and refracted rays, as well as the rays that undergo total internal reflection, are followed at the ocean surface, which is assumed smooth. The ocean floor is represented by a Lambert surface. The radiance and flux are given for two wavelengths, three solar angles, shallow and deep oceans, various albedos of ocean floor, various depths in atmosphere and ocean, and with and without clouds in the atmosphere.

  10. History of one family of atmospheric radiative transfer codes

    NASA Astrophysics Data System (ADS)

    Anderson, Gail P.; Wang, Jinxue; Hoke, Michael L.; Kneizys, F. X.; Chetwynd, James H., Jr.; Rothman, Laurence S.; Kimball, L. M.; McClatchey, Robert A.; Shettle, Eric P.; Clough, Shepard (.; Gallery, William O.; Abreu, Leonard W.; Selby, John E. A.

    1994-12-01

    Beginning in the early 1970's, the then Air Force Cambridge Research Laboratory initiated a program to develop computer-based atmospheric radiative transfer algorithms. The first attempts were translations of graphical procedures described in a 1970 report on The Optical Properties of the Atmosphere, based on empirical transmission functions and effective absorption coefficients derived primarily from controlled laboratory transmittance measurements. The fact that spectrally-averaged atmospheric transmittance (T) does not obey the Beer-Lambert Law (T equals exp(-(sigma) (DOT)(eta) ), where (sigma) is a species absorption cross section, independent of (eta) , the species column amount along the path) at any but the finest spectral resolution was already well known. Band models to describe this gross behavior were developed in the 1950's and 60's. Thus began LOWTRAN, the Low Resolution Transmittance Code, first released in 1972. This limited initial effort has how progressed to a set of codes and related algorithms (including line-of-sight spectral geometry, direct and scattered radiance and irradiance, non-local thermodynamic equilibrium, etc.) that contain thousands of coding lines, hundreds of subroutines, and improved accuracy, efficiency, and, ultimately, accessibility. This review will include LOWTRAN, HITRAN (atlas of high-resolution molecular spectroscopic data), FASCODE (Fast Atmospheric Signature Code), and MODTRAN (Moderate Resolution Transmittance Code), their permutations, validations, and applications, particularly as related to passive remote sensing and energy deposition.

  11. Optical remote diagnostics of atmospheric propagating beams of ionizing radiation

    DOEpatents

    Karl JR., Robert R.

    1990-03-06

    Data is obtained for use in diagnosing the characteristics of a beam of ionizing radiation, such as charged particle beams, neutral particle beams, and gamma ray beams. In one embodiment the beam is emitted through the atmosphere and produces nitrogen fluorescence during passage through air. The nitrogen fluorescence is detected along the beam path to provide an intensity from which various beam characteristics can be calculated from known tabulations. Optical detecting equipment is preferably located orthogonal to the beam path at a distance effective to include the entire beam path in the equipment field of view.

  12. Effect of chlorofluoromethane infrared radiation on zonal atmospheric temperatures

    NASA Technical Reports Server (NTRS)

    Dickinson, R. E.; Donahue, T. M.; Liu, S. C.

    1978-01-01

    Estimates are made of changes in the atmospheric climate due to the radiative effects of 10 ppb of chlorofluoromethanes (CFM's). The estimates are derived on the basis of a 12-layer stratospheric general circulation model with a specified change of ocean temperature. Two tropical maxima in zonal average temperature change were observed: one in the upper troposphere and one centered at the tropopause. The temperature change exceeds the surface temperature change by a factor of at least two. If the 1975 CFM emission rate were to continue indefinitely, stratospheric water-vapor concentrations would increase by up to 60% due to CFM radiative effects. This would reduce ozone concentrations by an additional 4% of the natural ozone column.

  13. Atmospheric Radiation Measurement (ARM) Data from Niamey, Niger for the Radiative Atmospheric Divergence using AMF, GERB and AMMA Stations (RADAGAST)

    DOE Data Explorer

    The Atmospheric Radiation Measurement (ARM) Program is the largest global change research program supported by the U.S. Department of Energy. The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. To achieve this goal, ARM scientists and researchers around the world use continuous data obtained through the ARM Climate Research Facility. The ARM Mobile Facility (AMF) operates at non-permanent sites selected by the ARM Program. Sometimes these sites can become permanent ARM sites, as was the case with Graciosa Island in the Azores. It is now known as the Eastern North Atlantic permanent site. In January 2006 the AMF deployed to Niamey, Niger, West Africa, at the Niger Meteorological Office at Niamey International Airport. This deployment was timed to coincide with the field phases and Special Observing Periods of the African Monsoon Multidisciplinary Analysis (AMMA). The ARM Program participated in this international effort as a field campaign called "Radiative Divergence using AMF, GERB and AMMA Stations (RADAGAST).The primary purpose of the Niger deployment was to combine an extended series of measurements from the AMF with those from the Geostationary Earth Radiation Budget (GERB) Instrument on the Meteosat operational geostationary satellite in order to provide the first well-sampled, direct estimates of the divergence of solar and thermal radiation across the atmosphere. A large collection of data plots based on data streams from specific instruments used at Niamey are available via a link from ARM's Niamey, Niger site information page. Other data can be found at the related websites mentioned above and in the ARM Archive. Users will be requested to create a password, but the plots and data files are free for viewing and downloading. The ARM Archive physically resides at the Oak Ridge National Laboratory.

  14. Three Dimensional Atmospheric Radiative Transfer-Applications and Methods Comparison

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert F.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    We review applications of 3D radiative transfer in the atmosphere, emphasizing the wide spectrum of scales important to remote sensing and modeling of cloud fields, and the characteristic scales introduced into observed radiances and fluxes by the distribution of photon pathlengths at conservative and absorbing wavelengths. We define the "plane-parallel bias", which is a measure of the importance of 3D cloud structure in large-scale models, and the "independent pixel errors" that quantify the significance of 3D effects in remote sensing, and emphasize their relative magnitude and scale dependence. A variety of approaches in current use in 3D radiative transfer, and issues of speed, accuracy, and flexibility are summarized. We also describe a recently initiated "International Intercomparison of 3-Dimensional Radiation Codes", or I3RC. I3RC is a 3-phase effort that has as its goals to: (1) understand the errors and limits of 3D methods; (2) provide "baseline" cases for future 3D code development; (3) promote sharing of 3D tools; (4) derive guidelines for 3D tool selection; and (5) improve atmospheric science education in 3D radiative transfer. Selected results from Phases 1 and 2 of I3RC are discussed. These are taken from five cloud fields: a 1D field of bar clouds, a 2D radar-derived field, a 3D Landsat-derived field, a stratiform cloud from the model of C. Moeng, and a convective cloud from the model of B. Stevens. Computations have been carried out for three monochromatic wavelengths (one conservative, one absorptive, and one thermal) and two solar zenith angles (0, 60 degrees).

  15. Observations of the Earth's Radiation Budget in relation to atmospheric hydrology. 4: Atmospheric column radiative cooling over the world's oceans

    NASA Technical Reports Server (NTRS)

    Stephens, Graeme L.; Slingo, Anthony; Webb, Mark J.; Minnett, Peter J.; Daum, Peter H.; Kleinman, Lawrence; Wittmeyer, Ian; Randall, David A.

    1994-01-01

    This paper introduces a simple method for deriving climatological values of the longwave flux emitted from the clear sky atmosphere to the ice-free ocean surface. It is shown using both theory and data from simulations how the ratio of the surface to top-of-atmosphere (TOA) flux is a simple function of water vapor (W) and a validation of the simple relationship is presented based on a limited set of surface flux measurements. The rms difference between the retrieved surface fluxes and the simulated surface fluxes is approximately 6 W/sq m. The clear sky column cooling rate of the atmosphere is derived from the Earth Radiation Budget Experiment (ERBE) values of the clear sky TOA flux and the surface flux retrieved using Special Scanning Microwave Imager (SSM/I) measurements of w together with ERBE clear sky fluxes. The relationship between this column cooling rate, w, and the sea surface temperature (SST) is explored and it is shown how the cooling rate systematically increases as both w and SST increase. The uncertainty implied in these estmates of cooling are approximately +/- 0.2 K/d. The effects of clouds on this longwave cooling are also explored by placing bounds on the possible impact of clouds on the column cooling rate based on certain assumptions about the effect of clouds on the longwave flux to the surface. It is shown how the longwave effects of clouds in a moist atmosphere where the column water vapor exceeds approximately 30 kg/sq m may be estimated from presently available satellite data with an uncertainty estimated to be approximately 0.2 K/d. Based on an approach described in this paper, we show how clouds in these relatively moist regions decrease the column cooling by almost 50% of the clear sky values and the existence of significant longitudinal gradients in column radiative heating across the equatorial and subtropical Pacific Ocean.

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

    PubMed

    O'Brien, K; Sauer, H H

    2003-01-01

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

  17. Radiative characteristics for atmospheric models from lidar sounding and AERONET

    NASA Astrophysics Data System (ADS)

    Sapunov, Maxim; Kuznetsov, Anatoly; Efremenko, Dmitry; Bochalov, Valentin; Melnikova, Irina; Samulenkov, Dimity; Vasilyev, Alexander; Poberovsky, Anatoly; Frantsuzova, Inna

    2016-04-01

    Optical models of atmospheric aerosols above of St. Petersburg are constraint on the base of the results of lidar sounding. The lidar system of the Resource Center "Observatory of environmental safety" of the St. Petersburg University Research Park is situated the city center, Vasilievsky Island. The measurements of the vertical profile of velocity and wind direction in the center of St. Petersburg for 2014 -2015 are fulfilled in addition. Height of laser sounding of aerosols is up to 25 km and wind up to 12 km. Observations are accomplished in the daytime and at night and mapped to vertical profiles of temperature, humidity, wind speed and pressure obtained from radiosounding in Voeikovo (St. Petersburg suburb). Results of wind observations are compared with those of upper-air measurements of meteorological service in Voeikovo. The distance between the points of observation is 25 km. Statistics of wind directions at different heights are identified. The comparison is based on the assumption of homogeneity of the wind field on such a scale. In most cases, good agreement between the observed vertical profiles of wind, obtained by both methods is appeared. However, there were several cases, when the results differ sharply or at high altitudes, or, on the contrary, in the surface layer. The analysis of the impact of wind, temperature, and humidity profiles in the atmosphere on the properties and dynamics of solid impurities is implemented. Comparison with AOT results from AERONET observations in St. Petersburg suburb Peterhof is done. It is shown that diurnal and seasonal variations of optical and morphological parameters of atmospheric aerosols in the pollution cap over the city to a large extent determined by the variability of meteorological parameters. The results of the comparison are presented and possible explanation of the differences is proposed. Optical models of the atmosphere in day and night time in different seasons are constructed from lidar and AERONET

  18. Algorithmic vs. finite difference Jacobians for infrared atmospheric radiative transfer

    NASA Astrophysics Data System (ADS)

    Schreier, Franz; Gimeno García, Sebastián; Vasquez, Mayte; Xu, Jian

    2015-10-01

    Jacobians, i.e. partial derivatives of the radiance and transmission spectrum with respect to the atmospheric state parameters to be retrieved from remote sensing observations, are important for the iterative solution of the nonlinear inverse problem. Finite difference Jacobians are easy to implement, but computationally expensive and possibly of dubious quality; on the other hand, analytical Jacobians are accurate and efficient, but the implementation can be quite demanding. GARLIC, our "Generic Atmospheric Radiation Line-by-line Infrared Code", utilizes algorithmic differentiation (AD) techniques to implement derivatives w.r.t. atmospheric temperature and molecular concentrations. In this paper, we describe our approach for differentiation of the high resolution infrared and microwave spectra and provide an in-depth assessment of finite difference approximations using "exact" AD Jacobians as a reference. The results indicate that the "standard" two-point finite differences with 1 K and 1% perturbation for temperature and volume mixing ratio, respectively, can exhibit substantial errors, and central differences are significantly better. However, these deviations do not transfer into the truncated singular value decomposition solution of a least squares problem. Nevertheless, AD Jacobians are clearly recommended because of the superior speed and accuracy.

  19. Atmospheric Radiation Measurement site atmospheric state best estimates for Atmospheric Infrared Sounder temperature and water vapor retrieval validation

    NASA Astrophysics Data System (ADS)

    Tobin, David C.; Revercomb, Henry E.; Knuteson, Robert O.; Lesht, Barry M.; Strow, L. Larrabee; Hannon, Scott E.; Feltz, Wayne F.; Moy, Leslie A.; Fetzer, Eric J.; Cress, Ted S.

    2006-05-01

    The Atmospheric Infrared Sounder (AIRS) is the first of a new generation of advanced satellite-based atmospheric sounders with the capability of obtaining high-vertical resolution profiles of temperature and water vapor. The high-accuracy retrieval goals of AIRS (e.g., 1 K RMS in 1 km layers below 100 mbar for air temperature, 10% RMS in 2 km layers below 100 mbar for water vapor concentration), combined with the large temporal and spatial variability of the atmosphere and difficulties in making accurate measurements of the atmospheric state, necessitate careful and detailed validation using well-characterized ground-based sites. As part of ongoing AIRS Science Team efforts and a collaborative effort between the NASA Earth Observing System (EOS) project and the Department of Energy Atmospheric Radiation Measurement (ARM) program, data from various ARM and other observations are used to create best estimates of the atmospheric state at the Aqua overpass times. The resulting validation data set is an ensemble of temperature and water vapor profiles created from radiosondes launched at the approximate Aqua overpass times, interpolated to the exact overpass time using time continuous ground-based profiles, adjusted to account for spatial gradients within the Advanced Microwave Sounding Unit (AMSU) footprints, and supplemented with limited cloud observations. Estimates of the spectral surface infrared emissivity and local skin temperatures are also constructed. Relying on the developed ARM infrastructure and previous and ongoing characterization studies of the ARM measurements, the data set provides a good combination of statistics and accuracy which is essential for assessment of the advanced sounder products. Combined with the collocated AIRS observations, the products are being used to study observed minus calculated AIRS spectra, aimed at evaluation of the AIRS forward radiative transfer model, AIRS observed radiances, and temperature and water vapor profile

  20. Overview of Atmospheric Ionizing Radiation (AIR) research: SST-present

    NASA Astrophysics Data System (ADS)

    Wilson, J.; Goldhagen, P.; Rafnson, V.; Clem, J.; Deangelis, G.

    The Super Sonic Transport (SST) program, proposed in 1961, first raised concern for the exposure of pregnant passengers and crew by solar energetic particles (SEP), and neutrons were suspected to have a main role in effects due to particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray exposures, with the largest contribution from neutrons above 10 MeV. The FAA Standing Committee provided recommendations on SST radiobiological issues and operational requirements. The lowering of ICRP-recommended exposure limits (1990) with the classification of aircrew as "radiation workers" renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum (June 1997) and studies of effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in 2000 and more recent European aircrew epidemiological studies of health outcomes brings renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented.

  1. Overview of atmospheric ionizing radiation (AIR) Research: SST-present

    NASA Astrophysics Data System (ADS)

    Wilson, J. W.; Goldhagen, P.; Rafnsson, V.; Clem, J. M.; De Angelis, G.; Friedberg, W.

    The Supersonic Transport (SST) program proposed in 1961, first raised concern for the exposure of pregnant occupants by solar energetic particles (SEP), and neutrons were suspected to have a main role in particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray exposures, with the largest contribution from neutrons above 10 MeV. The FAA Advisory Committee on the Radiobiological Aspects of the SST provided operational requirements. The more recent lowering of ICRP-recommended exposure limits 1990 with the classification of aircrew as "radiation workers" renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum June 1997 and studies on effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in year 2000 and recent European aircrew epidemiological studies of health outcomes bring renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented.

  2. Overview of atmospheric ionizing radiation (AIR) research: SST-present.

    PubMed

    Wilson, J W; Goldhagen, P; Rafnsson, V; Clem, J M; De Angelis, G; Friedberg, W

    2003-01-01

    The Supersonic Transport (SST) program, proposed in 1961, first raised concern for the exposure of pregnant occupants by solar energetic particles (SEP), and neutrons were suspected to have a main role in particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray exposures, with the largest contribution from neutrons above 10 MeV. The FAA Advisory Committee on the Radiobiological Aspects of the SST provided operational requirements. The more recent lowering of ICRP-recommended exposure limits (1990) with the classification of aircrew as "radiation workers" renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum (June 1997) and studies on effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in year 2000 and recent European aircrew epidemiological studies of health outcomes bring renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented. PMID:14727657

  3. Overview of atmospheric ionizing radiation (AIR) research: SST-present

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Goldhagen, P.; Rafnsson, V.; Clem, J. M.; De Angelis, G.; Friedberg, W.

    2003-01-01

    The Supersonic Transport (SST) program, proposed in 1961, first raised concern for the exposure of pregnant occupants by solar energetic particles (SEP), and neutrons were suspected to have a main role in particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray exposures, with the largest contribution from neutrons above 10 MeV. The FAA Advisory Committee on the Radiobiological Aspects of the SST provided operational requirements. The more recent lowering of ICRP-recommended exposure limits (1990) with the classification of aircrew as "radiation workers" renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum (June 1997) and studies on effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in year 2000 and recent European aircrew epidemiological studies of health outcomes bring renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented. Published by Elsevier Ltd on behalf of COSPAR.

  4. Overview of Atmospheric Ionizing Radiation (AIR) Research: SST - Present

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Goldhagen, P.; Rafnsson, V.; Clem, J. M.; DeAngelis, G.; Friedberg, W.

    2002-01-01

    The Supersonic Transport (SST) program, proposed in 1961, first raised concern for the exposure of pregnant occupants by solar energetic particles (SEP), and neutrons were suspected to have a main role in particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray (GCR) exposures, with the largest contribution from neutrons above 10 MeV. The FAA Advisory Committee on the Radiobiological Aspects of the SST provided operational requirements. The more recent (1990) lowering of recommended exposure limits by the International Commission on Radiological Protection with the classification of aircrew as "radiation workers" renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum (June 1997) and studies on effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in year 2000 and recent European aircrew epidemiological studies of health outcomes bring renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented.

  5. The radiation balance of the earth-atmosphere system from Nimbus 3 radiation measurements

    NASA Technical Reports Server (NTRS)

    Raschke, E.; Vonderhaar, T. H.; Pasternak, M.; Bandeen, W. R.

    1973-01-01

    The radiation balance of the earth-atmosphere system and its components was computed from global measurements of radiation reflected and emitted from the earth to space. These measurements were made from the meteorological satellite Nimbus 3 during the periods from April 16 to August 15, 1969; October 3 to 17, 1969; and January 21 to February 3, 1970. Primarily the method of evaluation, its inherent assumptions, and possible error sources were discussed. Results are presented by various methods: (1) global, hemispherical, and zonal averages obtained from measurements in all semimonthly periods and (2) global maps of the absorbed solar radiation, the albedo, the outgoing longwave radiation, and the radiation balance obtained from measurements during semimonthly periods in each season (May 1 to 15, July 16 to 31, and October 3 to 17, 1969, and January 21 to February 3, 1970). Annual global averages of the albedo and of the outgoing longwave radiation were determined. These values balance to within 1 percent the annual global energy input by solar radiation that was computed for a solar constant.

  6. Fast adjustment of the climate system to changes in atmospheric CO2 and solar radiation

    NASA Astrophysics Data System (ADS)

    Cao, L.; Caldeira, K.; Bala, G.

    2011-12-01

    A key issue in the study of global climate change is the climate response to external forcing. When radiative forcing is applied to the climate system, the climate system starts to respond, resulting in changes in temperature and other fields. A new quasi-equilibrium climate state is achieved when the global mean net energy balance at the top-of-atmosphere returns to zero. The adjustment of the climate system is governed by different processes on different timescales. Within days to months, the climate system adjusts mainly to the imposed forcing and the change of land surface temperature. On longer timescale of years to centuries, when the ocean temperature starts to respond, changes in sea surface temperature exert a strong control on the adjustment of the climate system. By performing ensemble simulations using Hadley Center climate model, HadCM3L, we investigate climate system response to the applied forcing in the forms of additional atmospheric carbon dioxide and an increase in solar insolation. Both carbon dioxide and solar forcing affects the Earth's radiation balance and carbon dioxide also affects the climate system through its impact on plant stomata. We focus on the daily evolution of climate response within a timescale of one month over land and oceans. We will provide a mechanistic understanding of why increasing atmospheric CO2 causes a reduction in global-mean precipitation in the absence of sea surface temperature change. We will also discuss the adjustment of radiative forcing and the usefulness in radiative forcing as a predictor of equilibrium climate change. A discussion of the climate response from daily to millennium timescale will also be presented.

  7. Evaluating Direct Radiative Effects of Absorbing Aerosols on Atmospheric Dynamics with Aquaplanet and Regional Model Results

    NASA Astrophysics Data System (ADS)

    Can, Ö.; Tegen, I.; Quaas, J.

    2015-12-01

    Effects of absorbing aerosol on atmospheric dynamics are usually investigated with help of general circulation models or also regional models that represent the atmospheric system as realistic as possible. Reducing the complexity of models used to study the effects of absorbing aerosol on atmospheric dynamics helps to understand underlying mechanisms. In this study, by using ECHAM6 General Circulation Model (GCM) in an Aquaplanet setting and using simplified aerosol climatology, an initial idealization step has been taken. The analysis only considers direct radiative effects, furthering the reduction of complex model results. The simulations include cases including aerosol radiative forcing, no aerosol forcing, coarse mode aerosol forcing only (as approximation for mineral dust forcing) and forcing with increased aerosol absorption. The results showed that increased absorption affects cloud cover mainly in subtropics. Hadley circulation is found to be weakened in the increased absorption case. To compare the results of the idealized model with a more realistic model setting, the results of the regional model COSMO-MUSCAT that includes interactive mineral dust aerosol and considers the effects of dust radiative forcing are also analyzed. The regional model computes the atmospheric circulation for the year 2007 twice, including the feedback of dust and excluding the dust aerosol forcing. It is investigated to which extent the atmospheric response to the dust forcing agrees with the simplified Aquaplanet results. As expected, in the regional model mineral dust causes an increase in the temperature right above the dust layer while reducing the temperature close to the surface. In both models the presence of aerosol forcing leads to increased specific humidity, close to ITCZ. Notwithstanding the difference magnitudes, comparisons of the global aquaplanet and the regional model showed similar patterns. Further detailed comparisons will be presented.

  8. Environmental assessment for the Atmospheric Radiation Measurement (ARM) Program: Southern Great Plains Cloud and Radiation Testbed (CART) site

    SciTech Connect

    Policastro, A.J.; Pfingston, J.M.; Maloney, D.M.; Wasmer, F.; Pentecost, E.D.

    1992-03-01

    The Atmospheric Radiation Measurement (ARM) Program is aimed at supplying improved predictive capability of climate change, particularly the prediction of cloud-climate feedback. The objective will be achieved by measuring the atmospheric radiation and physical and meteorological quantities that control solar radiation in the earth`s atmosphere and using this information to test global climate and related models. The proposed action is to construct and operate a Cloud and Radiation Testbed (CART) research site in the southern Great Plains as part of the Department of Energy`s Atmospheric Radiation Measurement Program whose objective is to develop an improved predictive capability of global climate change. The purpose of this CART research site in southern Kansas and northern Oklahoma would be to collect meteorological and other scientific information to better characterize the processes controlling radiation transfer on a global scale. Impacts which could result from this facility are described.

  9. Identification of patterns in diffraction intensities affected by radiation exposure.

    PubMed

    Borek, Dominika; Dauter, Zbigniew; Otwinowski, Zbyszek

    2013-01-01

    In an X-ray diffraction experiment, the structure of molecules and the crystal lattice changes owing to chemical reactions and physical processes induced by the absorption of X-ray photons. These structural changes alter structure factors, affecting the scaling and merging of data collected at different absorbed doses. Many crystallographic procedures rely on the analysis of consistency between symmetry-equivalent reflections, so failure to account for the drift of their intensities hinders the structure solution and the interpretation of structural results. The building of a conceptual model of radiation-induced changes in macromolecular crystals is the first step in the process of correcting for radiation-induced inconsistencies in diffraction data. Here the complexity of radiation-induced changes in real and reciprocal space is analysed using matrix singular value decomposition applied to multiple complete datasets obtained from single crystals. The model consists of a resolution-dependent decay correction and a uniform-per-unique-reflection term modelling specific radiation-induced changes. This model is typically sufficient to explain radiation-induced effects observed in diffraction intensities. This analysis will guide the parameterization of the model, enabling its use in subsequent crystallographic calculations.

  10. Enhancement of atmospheric radiation by an aerosol layer

    NASA Technical Reports Server (NTRS)

    Michelangeli, Diane V.; Yung, Yuk L.; Shia, Run-Lie; Eluszkiewicz, Janusz; Allen, Mark; Crisp, David

    1992-01-01

    The presence of a stratospheric haze layer may produce increases in both the actinic flux and the irradiance below this layer. Such haze layers result from the injection of aerosol-forming material into the stratosphere by volcanic eruptions. Simple heuristic arguments show that the increase in flux below the haze layer, relative to a clear sky case, is a consequence of 'photon trapping'. The magnitude of these flux perturbations, as a function of aerosol properties and illumination conditions, is explored with a new radiative transfer model that can accurately compute fluxes in an inhomogeneous atmosphere with nonconservative scatterers having arbitrary phase function. One calculated consequence of the El Chichon volcanic eruption is an increase in the midday surface actinic flux at 20 deg N latitude, summer, by as much as 45 percent at 2900 A. This increase in flux in the UV-B wavelength range was caused entirely by aerosol scattering, without any reduction in the overhead ozone column.

  11. An infrared radiation routine for use in numerical atmospheric models

    NASA Technical Reports Server (NTRS)

    Chow, M.-D.; Arking, A.

    1978-01-01

    Previous methods for calculating radiative fluxes due to water vapor and CO2 absorption bands are extended to take into consideration the entire water vapor and CO2 bands, including e-type absorption in the window region and the overlapping of different absorptions. Cooling rate profiles in the water vapor bands for a tropical atmosphere were computed by a detailed line-by-line method and by a far-wing approximation method, and the error of both methods is less than 0.2 C/day. Cooling rate profiles in the 15 micron band including overlapping of CO2 absorption with water vapor were calculated by a method in which flux transmittance is computed by means of a linear expansion and the multiplication rule, and maximum errors of 0.3 C/day were found in comparison with the exact line-by-line method.

  12. Enhancement of atmospheric radiation by an aerosol layer.

    PubMed

    Michelangeli, D V; Allen, M; Yung, Y L; Shia, R L; Crisp, D; Eluszkiewicz, J

    1992-01-20

    The presence of a stratospheric haze layer may produce increases in both the actinic flux and the irradiance below this layer. Such haze layers result from the injection of aerosol-forming material into the stratosphere by volcanic eruptions. Simple heuristic arguments show that the increase in flux below the haze layer, relative to a clear sky case, is a consequence of "photon trapping." We explore the magnitude of these flux perturbations, as a function of aerosol properties and illumination conditions, with a new radiative transfer model that can accurately compute fluxes in an inhomogenous atmosphere with nonconservative scatterers having arbitrary phase function. One calculated consequence of the El Chichon volcanic eruption is an increase in the midday surface actinic flux at 20 degrees N latitude, summer, by as much as 45% at 2900 angstroms. This increase in flux in the UV-B wavelength range was caused entirely by aerosol scattering, without any reduction in the overhead ozone column.

  13. Atmospheric radiation measurement: A program for improving radiative forcing and feedback in general circulation models

    SciTech Connect

    Patrinos, A.A. ); Renne, D.S.; Stokes, G.M. ); Ellingson, R.G. )

    1991-01-01

    The Atmospheric Radiation Measurement (ARM) Program is a key element of the Department of Energy's (DOE's) global change research strategy. ARM represents a long-term commitment to conduct comprehensive studies of the spectral atmospheric radiative energy balance profile for a wide range of cloud conditions and surface types, and to develop the knowledge necessary to improve parameterizations of radiative processes under various cloud regimes for use in general circulation models (GCMs) and related models. The importance of the ARM program is a apparent from the results of model assessments of the impact on global climate change. Recent studies suggest that radiatively active trace gas emissions caused by human activity can lead to a global warming of 1.5 to 4.5 degrees Celsius and to important changes in water availability during the next century (Cess, et al. 1989). These broad-scale changes can be even more significant at regional levels, where large shifts in temperature and precipitation patterns are shown to occur. However, these analyses also indicate that considerable uncertainty exists in these estimates, with the manner in which cloud radiative processes are parameterized among the most significant uncertainty. Thus, although the findings have significant policy implications in assessment of global and regional climate change, their uncertainties greatly influence the policy debate. ARM's highly focused observational and analytical research is intended to accelerate improvements and reduce key uncertainties associated with the way in which GCMs treat cloud cover and cloud characteristics and the resulting radiative forcing. This paper summarizes the scientific context for ARM, ARM's experimental approach, and recent activities within the ARM program.

  14. Atmospheric radiation measurement: A program for improving radiative forcing and feedback in general circulation models

    SciTech Connect

    Patrinos, A.A.; Renne, D.S.; Stokes, G.M.; Ellingson, R.G.

    1991-01-01

    The Atmospheric Radiation Measurement (ARM) Program is a key element of the Department of Energy`s (DOE`s) global change research strategy. ARM represents a long-term commitment to conduct comprehensive studies of the spectral atmospheric radiative energy balance profile for a wide range of cloud conditions and surface types, and to develop the knowledge necessary to improve parameterizations of radiative processes under various cloud regimes for use in general circulation models (GCMs) and related models. The importance of the ARM program is a apparent from the results of model assessments of the impact on global climate change. Recent studies suggest that radiatively active trace gas emissions caused by human activity can lead to a global warming of 1.5 to 4.5 degrees Celsius and to important changes in water availability during the next century (Cess, et al. 1989). These broad-scale changes can be even more significant at regional levels, where large shifts in temperature and precipitation patterns are shown to occur. However, these analyses also indicate that considerable uncertainty exists in these estimates, with the manner in which cloud radiative processes are parameterized among the most significant uncertainty. Thus, although the findings have significant policy implications in assessment of global and regional climate change, their uncertainties greatly influence the policy debate. ARM`s highly focused observational and analytical research is intended to accelerate improvements and reduce key uncertainties associated with the way in which GCMs treat cloud cover and cloud characteristics and the resulting radiative forcing. This paper summarizes the scientific context for ARM, ARM`s experimental approach, and recent activities within the ARM program.

  15. Downward Atmospheric Longwave Radiation in the City of Sao Paulo

    SciTech Connect

    Barbaro, Eduardo W.; Oliveira, Amauri P.; Soares, Jacyra; Ferreira, Mauricio J.; Boznar, Marija Z.; Mlakar, Primoz; Escobedo, Joao F.

    2009-03-11

    This work evaluates objectively the consistency and quality of a 9 year dataset based on 5 minute average values of downward longwave atmospheric (LW) emission, shortwave radiation, temperature and relative humidity. All these parameters were observed simultaneously and continuously from 1997 to 2006 in the IAG micrometeorological platform, located at the top of the IAG-USP building. The pyrgeometer dome emission effect was removed using neural network technique reducing the downward long wave atmospheric emission error to 3.5%. The comparison, between the monthly average values of LW emission observed in Sao Paulo and satellite estimates from SRB-NASA project, indicated a very good agreement. Furthermore, this work investigates the performance of 10 empirical expressions to estimate the LW emission at the surface. The comparison between the models indicates that Brunt's one presents the better results, with smallest ''MBE,''''RMSE'' and biggest ''d'' index of agreement, therefore Brunt is the most indicated model to estimate LW emission under clear sky conditions in the city of Sao Paulo.

  16. Atmospheric Radiation Measurement Program facilities newsletter, January 2000

    SciTech Connect

    Sisterson, D.L.

    2000-02-16

    The subject of this newsletter is the ARM unmanned aerospace vehicle program. The ARM Program's focus is on climate research, specifically research related to solar radiation and its interaction with clouds. The SGP CART site contains highly sophisticated surface instrumentation, but even these instruments cannot gather some crucial climate data from high in the atmosphere. The Department of Energy and the Department of Defense joined together to use a high-tech, high-altitude, long-endurance class of unmanned aircraft known as the unmanned aerospace vehicle (UAV). A UAV is a small, lightweight airplane that is controlled remotely from the ground. A pilot sits in a ground-based cockpit and flies the aircraft as if he were actually on board. The UAV can also fly completely on its own through the use of preprogrammed computer flight routines. The ARM UAV is fitted with payload instruments developed to make highly accurate measurements of atmospheric flux, radiance, and clouds. Using a UAV is beneficial to climate research in many ways. The UAV puts the instrumentation within the environment being studied and gives scientists direct measurements, in contrast to indirect measurements from satellites orbiting high above Earth. The data collected by UAVs can be used to verify and calibrate measurements and calculated values from satellites, therefore making satellite data more useful and valuable to researchers.

  17. Atmospheric Radiation Measurement (ARM) Data from the ARM Aerial Facility

    DOE Data Explorer

    The Atmospheric Radiation Measurement (ARM) Program is the largest global change research program supported by the U.S. Department of Energy. The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. ARM data is collected both through permanent monitoring stations and field campaigns around the world. Airborne measurements required to answer science questions from researchers or to validate ground data are also collected. To find data from all categories of aerial operations, follow the links from the AAF information page at http://www.arm.gov/sites/aaf. Tables of information will provide start dates, duration, lead scientist, and the research site for each of the named campaigns. The title of a campaign leads, in turn, to a project description, contact information, and links to the data. Users will be requested to create a password, but the data files are free for viewing and downloading. The ARM Archive physically resides at the Oak Ridge National Laboratory.

  18. Atmospheric Radiation Measurement Climate Research Facility (ACRF) Annual Report 2007

    SciTech Connect

    LR Roeder

    2007-12-01

    This annual report describes the purpose and structure of the program, and presents key accomplishments in 2007. Notable achievements include: • Successful review of the ACRF as a user facility by the DOE Biological and Environmental Research Advisory Committee. The subcommittee reinforced the importance of the scientific impacts of this facility, and its value for the international research community. • Leadership of the Cloud Land Surface Interaction Campaign. This multi-agency, interdisciplinary field campaign involved enhanced surface instrumentation at the ACRF Southern Great Plains site and, in concert with the Cumulus Humilis Aerosol Processing Study sponsored by the DOE Atmospheric Science Program, coordination of nine aircraft through the ARM Aerial Vehicles Program. • Successful deployment of the ARM Mobile Facility in Germany, including hosting nearly a dozen guest instruments and drawing almost 5000 visitors to the site. • Key advancements in the representation of radiative transfer in weather forecast models from the European Centre for Medium-Range Weather Forecasts. • Development of several new enhanced data sets, ranging from best estimate surface radiation measurements from multiple sensors at all ACRF sites to the extension of time-height cloud occurrence profiles to Niamey, Niger, Africa. • Publication of three research papers in a single issue (February 2007) of the Bulletin of the American Meteorological Society.

  19. The Radiative Effects of Martian Water Ice Clouds on the Local Atmospheric Temperature Profile

    NASA Technical Reports Server (NTRS)

    Colaprete, Anthony; Toon, Owen B.

    2000-01-01

    Mars Pathfinder made numerous discoveries, one of which was a deep temperature inversion that extended from about 15 km down to 8 km above the surface. It has been suggested by Haberle et al. (1999. J. Geophys. Res. 104, 8957-8974.) that radiative cooling by a water ice cloud may generate such an inversion. Clouds can strongly affect the local air temperature due to their ability to radiate efficiently in the infrared and due to the low air mass of the martian atmosphere, which allows the temperature to change during the relatively short lifetime of a cloud. We utilize a time-dependent microphysical aerosol model coupled to a radiative--convective model to explore the effects water ice clouds have on the local martian temperature profile. We constrain the dust and water vapor abundance using data from the Viking Missions and Mars Pathfinder. Water t ice clouds with visible optical depths of r > 0.1 form readily in these simulations. These clouds alter the local air temperature directly, through infrared cooling, and indirectly, by redistributing atmospheric dust. With this model we are able to reproduce the temperature inversions observed by Mars Pathfinder and Mars Global t Surveyor 2000 Academic Press

  20. Natural aerosols and atmospheric radiation: Impacts and consequent feedbacks on meteorology and photochemistry

    NASA Astrophysics Data System (ADS)

    Kushta, Jonilda; Astitha, Marina; Kallos, George

    2014-05-01

    The aim of this work is to study the complex direct, semi-direct and indirect links and feedbacks between natural aerosols, radiation budget and the meteorological and chemical state of the atmosphere. This is realized with the implementation of an integrated modeling system (RAMS/ICLAMS) for a ten day test period that includes an intense dust event over the Eastern Mediterranean region. The capabilities of this modeling system include the online coupling between chemical and meteorological processes, as well as the explicit treatment of cloud condensation, giant and ice nuclei (CCN, GCCN, IN), and size and humidity dependent optical properties for aerosols. The results from this work show that the presence of mineral dust leads to a linear reduction in solar radiation and nonlinear increase in net downward longwave radiation that is larger during daytime than nighttime. The magnitude of change in the radiation budget is determined by the vertical structure of the dust cloud and mainly its height. The perturbations in the radiation budget affect the air temperature and moisture vertical profile, leading to a cloud base lifting and redistribution of condensates. The explicit activation of aerosols as CCN and IN causes changes in the spatiotemporal patterns of the precipitation field during and after the event. Those influences are caused more by the indirect rather than the direct and semi-direct effects. The changes in the diffuse and direct components of the radiation budget lead to a net negative effect on the photolysis rates that, in turn, alter the pollutants distribution. Ozone concentration, in particular, is affected by dust in a non-monotonous way determined by the availability of ozone precursors.

  1. Atmospheric radiation measurement program facilities newsletter, April 2001.

    SciTech Connect

    Holdridge, D. J.

    2001-05-03

    Intensive Observation Period Projects Scheduled--Several IOP projects have been scheduled for the SGP CART site this spring. These projects either have already begun or will begin shortly. Radiosondes--The RS-90 Transition IOP is currently under way. The RS-90 model radiosonde is gradually replacing the older RS-80 model. Radiosondes are instrument packages attached to and launched by weather balloons. The instruments measure atmospheric pressure, temperature, and relative humidity as the balloon rises through the air. The new RS-90 model is a high-performance radiosonde with fast-response sensors capable of providing data for each variable every second. The relatively environmentally friendly package is constructed of cardboard and steel rather than Styrofoam, and it has a water-activated battery that contains no toxic substances. The RS-90 Transition IOP is taking place during April. Operators will launch both the old RS-80 and the new RS-90 radiosondes simultaneously once each day to obtain duplicate vertical profiles of the atmosphere for comparison. This procedure will also allow data users to test the output from the old and new radiosondes in models. Narrow Field of View (NFOV) Solar Spectrometer Cloud Optical Depth Retrieval Campaign--The NFOV IOP is scheduled to take place on May 7-August 31, 2001. A researcher from Pennsylvania State University will be deploying a dual-spectrometer instrument that measures the hemispheric flux and zenith NFOV radiance over a wavelength range of 300- 1000 nanometers. (One nanometer equals 1 billionth of a meter or 0.000000039 inches.) This wavelength range includes the ultraviolet, visible, and near-infrared spectra. These measurements are used to estimate cloud optical depth--a quantity related to the amount of solar radiation intercepted by a cloud--for broken cloud fields over vegetated surfaces. The IOP measurements will be compared with optical depth measurements made by SGP instruments. Precision Gas Sampling (PGS

  2. Atmospheric Radiation Measurement Program facilities newsletter, November 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-12-03

    Fall 2002 Intensive Operation Periods: Single Column Model and Unmanned Aerospace Vehicle--In an Intensive Operation Period (IOP) on November 3-23, 2002, researchers at the SGP CART site are collecting a detailed data set for use in improving the Single Column Model (SCM), a scaled-down climate model. The SCM represents one vertical column of air above Earth's surface and requires less computation time than a full-scale global climate model. Researchers first use the SCM to efficiently improve submodels of clouds, solar radiation transfer, and atmosphere-surface interactions, then implement the results in large-scale global models. With measured values for a starting point, the SCM predicts atmospheric variables during prescribed time periods. A computer calculates values for such quantities as the amount of solar radiation reaching the surface and predicts how clouds will evolve and interact with incoming light from the sun. Researchers compare the SCM's predictions with actual measurements made during the IOP, then adjust the submodels to make predictions more reliable. A second IOP conducted concurrently with the SCM IOP involves high-altitude, long-duration aircraft flights. The original plan was to use an unmanned aerospace vehicle (UAV), but the National Aeronautics and Space Administration (NASA) aircraft Proteus will be substituted because all UAVs have been deployed elsewhere. The UAV is a small, instrument-equipped, remote-control plane that is operated from the ground by a computer. The Proteus is a manned aircraft, originally designed to carry telecommunications relay equipment, that can be reconfigured for uses such as reconnaissance and surveillance, commercial imaging, launching of small space satellites, and atmospheric research. The plane is designed for two on-board pilots in a pressurized cabin, flying to altitudes up to 65,000 feet for as long as 18 hours. The Proteus has a variable wingspan of 77-92 feet and is 56 feet long. The plane can carry

  3. Non-LTE diagnositics of infrared radiation of Titan's atmosphere

    NASA Astrophysics Data System (ADS)

    Feofilov, Artem; Rezac, Ladislav; Kutepov, Alexander; Vinatier, Sandrine; Rey, Michael; Nikitin, Andrew; Tyuterev, Vladimir

    2016-06-01

    Yelle (1991) and Garcia-Comas et al, (2011) demonstrated the importance of accounting for the local thermodynamic equilibrium (LTE) breakdown in the middle and upper atmosphere of Titan for the interpretation of infrared radiances measured at these heights. In this work, we make further advance in this field by: • updating the non-LTE model of CH4 emissions in Titan's atmosphere and including a new extended database of CH4 spectroscopic parameters • studying the non-LTE CH4 vibrational level populations and the impact of non-LTE on limb infrared emissions of various CH4 ro-vibrational bands including those at 7.6 and 3.3 µm • implementing our non-LTE model into the LTE-based retrieval algorithm applied by Vinatier et al., (2015) for processing the Cassini/CIRS spectra. We demonstrate that accounting for non-LTE leads to an increase in temperatures retrieved from CIRS 7.6 µm limb emissions spectra (˜10 K at 600 km altitude) and estimate how this affects the trace gas density retrieval. Finally, we discuss the effects of including a large number of weak one-quantum and combinational bands on the calculated daytime limb 3.3 µm emissions and the impact they may have on the CH4 density retrievals from the Cassini VIMS 3.3 µm limb emission observations.

  4. Uncertainties in carbon dioxide radiative forcing in atmospheric general circulation models.

    PubMed

    Cess, R D; Zhang, M H; Potter, G L; Barker, H W; Colman, R A; Dazlich, D A; Del Genio, A D; Esch, M; Fraser, J R; Galin, V; Gates, W L; Hack, J J; Ingram, W J; Kiehl, J T; Lacis, A A; Le Treut, H; Li, Z X; Liang, X Z; Mahfouf, J F; McAvaney, B J; Meleshko, V P; Morcrette, J J; Randall, D A; Roeckner, E; Royer, J F; Sokolov, A P; Sporyshev, P V; Taylor, K E; Wang, W C; Wetherald, R T

    1993-11-19

    Global warming caused by an increase in the concentrations of greenhouse gases, is the direct result of greenhouse gas-induced radiative forcing. When a doubling of atmospheric carbon dioxide is considered, this forcing differed substantially among 15 atmospheric general circulation models. Although there are several potential causes, the largest contributor was the carbon dioxide radiation parameterizations of the models.

  5. Uncertainties in Carbon Dioxide Radiative Forcing in Atmospheric General Circulation Models

    NASA Technical Reports Server (NTRS)

    Cess, R. D.; Zhang, M.-H.; Potter, G. L.; Gates, W. L.; Taylor, K. E.; Barker, H. W.; Colman, R. A.; Fraser, J. R.; McAvaney, B. J.; Dazlich, D. A.; Randall, D. A.; DelGenio, A. D.; Lacis, A. A.; Esch, M.; Roeckner, E.; Galin, V.; Hack, J. J.; Kiehl, J. T.; Ingram, W. J.; LeTreut, H.

    1993-01-01

    Global warming, caused by an increase in the concentrations of greenhouse gases, is the direct result of greenhouse gas-induced radiative forcing. When a doubling of atmospheric carbon dioxide is considered, this forcing differed substantially among 15 atmospheric general circulation models. Although there are several potential causes, the largest contributor was the carbon dioxide radiation parameterizations of the models.

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

    SciTech Connect

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

    1990-08-01

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

  7. How stellar activity affects exoplanet's parameters estimation and exoplanet's atmosphere

    NASA Astrophysics Data System (ADS)

    Oshagh, Mahmoudreza

    2015-07-01

    The next large facility with the potential to characterize the atmosphere of exoplanets will be the James Webb Space Telescope (JWST), a 6.5 m telescope to be launched in 2018. The JWST will be equipped with four instruments; three in the near InfaRed (1-5 microns): NIRCAM, NIRSPEC and NIRISS, and one in the mid-InfraRed (5-28 microns): MIRI. MIRI is of particular interest to characterize temperate exoplanets; it includes an imager with three observing modes: imagery, coronagraphy and low resolution (R=100) spectroscopy, and an Integral Field Spectrometer with a spectral resolution around 3000. I will discuss the capabilities of the instrument to characterize exoplanets, showing simulations of transit observations, as well as direct imaging observations, which include instrumental test results. It should be stressed that the JWST is not dedicated to exoplanets and we can expect a large pressure on the observing time.

  8. Surface summertime radiative forcing by shallow cumuli at the Atmospheric Radiation Measurement Southern Great Plains site

    SciTech Connect

    Berg, Larry K.; Kassianov, Evgueni I.; Long, Charles N.; Mills Jr., David L.

    2011-01-08

    Although shallow cumuli are common over large areas of the globe, their impact on the surface radiative forcing has not been carefully evaluated. This study addresses this shortcoming by analyzing data from days with shallow cumuli collected over eight summers (2000-2007) at the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility (collectively ACRF) Southern Great Plains site. During periods with clouds, the average shortwave and longwave radiative forcings are 45.5 W m-2 and +11.6 W m-2, respectively. The forcing has been defined so that a negative (positive) forcing indicates a surface cooling (warming). On average, the shortwave forcing is negative, however, instances with positive shortwave forcing are observed approximately 20% of the time. These positive values of shortwave forcing are associated with three-dimensional radiative effects of the clouds. The three-dimensional effects are shown to be largest for intermediate cloud amounts. The magnitude of the three-dimensional effects decreased with averaging time, but it is not negligibly small even for large averaging times as long as four hours.

  9. Radiation resistance of methanogenic archaea from Siberian permafrost-affected soils

    NASA Astrophysics Data System (ADS)

    Morozova, Daria; Moeller, Ralf; Rettberg, Petra; Wagner, Dirk

    2007-08-01

    Methanogenic archaea from the Siberian permafrost-affected soils and from nonpermafrost habitats were exposed to solar UV- and ionizing radiation in order to assess their limits of survival. Metabolic activity and viability of methanogenic archaea in environmental samples remained unaffected by exposure to monochromatic and polychromatic UV radiation caused by the shielding of the soil layers. Pure methanogenic cultures isolated from the permafrost's active layer exhibit an increase in radioresistance to UV (20-fold) and ionizing radiation (32-fold) compared to the non-permafrost isolates. The F37 (UV radiation) and D37 (X-rays) values of the permafrost strain Methanosarcina sp. SMA-21 were 700 J m-2 and 6-12 kGy, respectively. This resistance is comparable to values for Deinococcus radiodurans (F37 640 Jm-2, D37 6-7 kGy). Due to the increased radiation-resistance of permafrost isolates, their long-term survival, and their anaerobic lithoautotrophic metabolism, methanogenic archaea from permafrost can be considered as suitable candidates in the search for microbial life in the Martian subsurface. The ESA mission Mars Express confirmed the existence of water on Mars, which is a fundamental requirement for life, as well as CH4 in the Martian atmosphere, which could only originate from active volcanism or from biological sources; both these results suggest that microbial life could still exist on Mars, for example in the form of subsurface lithoautotrophic ecosystems, which also exist in permafrost regions on Earth.

  10. Differential Meteoric Ablation and its affects in the atmosphere (Invited)

    NASA Astrophysics Data System (ADS)

    Plane, J. M.; Broadley, S. L.; Whalley, C. L.; Saunders, R. W.; Gomez Martin, J.; Janches, D.; Dyrud, L.

    2009-12-01

    Differential ablation occurs when the constituents of a molten meteoroid evaporate at different rates during the passage of the meteoroid through the upper atmosphere. This can result in relatively volatile elements (e.g., Na and K) evaporating more than 20 km higher than a refractory element such as Ca. This paper will describe a new chemical ablation model (CABMOD) which predicts the ablation rates of individual elements from a meteoroid under specified entry conditions. The model also treats ionization of the individual elements by hyperthermal collisions with air molecules. This data has been used to compute the fine structure in the altitude profile of the "head echo" which would be observed by a large aperture radar. Good agreement was found with observations from the Arecibo radar in Puerto Rico. CABMOD has also been used to explain the curious results of multiple common-volume lidar observations of meteor trails, and to predict the most likely composition of meteoric smoke particles which result from the recondensation of vaporized meteoroids.

  11. Ocean and atmosphere feedbacks affecting AMOC hysteresis in a GCM

    NASA Astrophysics Data System (ADS)

    Jackson, L. C.; Smith, R. S.; Wood, R. A.

    2016-10-01

    Theories suggest that the Atlantic Meridional Overturning Circulation (AMOC) can exhibit a hysteresis where, for a given input of fresh water into the north Atlantic, there are two possible states: one with a strong overturning in the north Atlantic (on) and the other with a reverse Atlantic cell (off). A previous study showed hysteresis of the AMOC for the first time in a coupled general circulation model (Hawkins et al. in Geophys Res Lett. doi: 10.1029/2011GL047208, 2011). In this study we show that the hysteresis found by Hawkins et al. (2011) is sensitive to the method with which the fresh water input is compensated. If this compensation is applied throughout the volume of the global ocean, rather than at the surface, the region of hysteresis is narrower and the off states are very different: when the compensation is applied at the surface, a strong Pacific overturning cell and a strong Atlantic reverse cell develops; when the compensation is applied throughout the volume there is little change in the Pacific and only a weak Atlantic reverse cell develops. We investigate the mechanisms behind the transitions between the on and off states in the two experiments, and find that the difference in hysteresis is due to the different off states. We find that the development of the Pacific overturning cell results in greater atmospheric moisture transport into the North Atlantic, and also is likely responsible for a stronger Atlantic reverse cell. These both act to stabilize the off state of the Atlantic overturning.

  12. Multi-decadal Change of Atmospheric Aerosols and their Effect on Surface Radiation

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diel, Thomas; Streets, David; Wild, Martin; Qian, Yun; Yu, Hongbin; Tan, Qian; Bian, Huisheng; Wang. Weiguo

    2012-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model GOCART along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007 during which a suite of aerosol data from satellite observations, ground-based measurements, and intensive field experiments have become available. Particularly: (1) We compare the model calculated clear sky downward radiation at the surface with surface network data from Baseline Surface Radiation Network (BSRN) and CMA (2) We compare the model and surface data with satellite derived downward radiation products from ISCCP and SRB (3) We analyze the long-term global and regional aerosol trends in major anthropogenic source regions (North America, Europe, Asia) that have been experiencing considerable changes of emissions during the three decades, dust and biomass burning regions that have large interannual variability, downwind regions that are directly affected by the changes in the source area, and remote regions that are considered to representing "background" conditions.

  13. Atmospheric radiation measurement program facilities newsletter, August 1999.

    SciTech Connect

    Sisterson, D.L.

    1999-09-03

    With the end of summer drawing near, the fall songbird migration season will soon begin. Scientists with the ARM Program will be able to observe the onset of the migration season as interference in the radar wind profiler (RWP) data. An RWP measures vertical profiles of wind and temperature directly above the radar from approximately 300 feet to 3 miles above the ground. The RWP accomplishes this by sending a pulse of electromagnetic energy skyward. Under normal conditions, the energy is scattered by targets in the atmosphere. Targets generally consist of atmospheric irregularities such as variations in temperature, humidity, and pressure over relatively short distances. During the spring and fall bird migration seasons, RWP beam signals are susceptible to overflying birds. The radar beams do not harm the birds, but the birds' presence hampers data collection by providing false targets to reflect the RWP beam, introducing errors into the data. Because of the wavelength of the molar beam, the number of individuals, and the small size of songbirds' bodies (compared to the larger geese or hawks), songbirds are quite likely to be sampled by the radar. Migrating birds usually fly with the prevailing wind, making their travel easier. As a result, winds from the south are ''enhanced'' or overestimated in the spring as the migrating birds travel northward, and winds from the north are overestimated in the fall as birds make their way south. This fact is easily confirmed by comparison of RWP wind data to wind data gathered by weather balloons, which are not affected by birds.

  14. Atmospheric Radiation Measurement Program facilities newsletter, January 2001.

    SciTech Connect

    Holdridge, D. J.

    2001-02-05

    In the realm of global climate modeling, numerous variables affect the state of the atmosphere and climate. One important area is soil moisture and temperature. The ARM Program uses several types of instruments to gather soil moisture information. An example is the soil water and temperature system (SWATS). A SWATS is located at each of 21 extended facility sites within the CART site boundary. Each system is configured to measure soil moisture and temperature at eight distinct subsurface levels. A special set of probes used in the SWATS measures soil temperature, soil-water potential, and volumetric water content. Sensors are placed at eight different depths below the soil surface, starting at approximately 5 cm (2 in.) below the surface and ending as deep as 175 cm (69 in.). Each site has two identical sets of probes buried 1 m (3.3 ft) apart, to yield duplicate measurements as a quality control measure. At some sites, impenetrable soil or rock layers prevented installation of probes at the deeper levels. The sensors are connected to an electronic data logger that collects and stores the data. Communication equipment transfers data from the site. All of the electronic equipment is housed in a weatherproof enclosure mounted on a concrete slab.

  15. Radiation profiles through the atmosphere measured by an auto controlled glider aircraft

    NASA Astrophysics Data System (ADS)

    Kräuchi, Andreas; Philipona, Rolf

    2014-05-01

    In 2011 radiation measurements through the atmosphere were made with a balloon borne short- and longwave net radiometer. These measurements were very promising and therefore new and improved sensors from Kipp&Zonen were used to equip a glider aircraft together with the standard Swiss radiosonde from Meteolabor AG. The glider serves as returning platform for the expensive and well calibrated radiation sensors. Double balloon technique is used to prevent pendulum motion during the ascent and to keep the radiation instruments as horizontal as possible. The built-in autopilot allows to return the gliderradiosonde to the launch site or to land it on predefined open space, which makes recovery much easier. The new return gliderradiosonde technique as well as new measurement possibilities will be shown. First measurements show radiation profiles through the atmosphere during different cloud conditions. Radiation profiles during different daytimes show the temporal resolution of vertical radiation profiles trough the atmosphere.

  16. Radiation-induced health effects on atmospheric flight crew members: clues for a radiation-related risk analysis.

    PubMed

    De Angelis, G; Caldora, M; Santaquilani, M; Scipione, R; Verdecchia, A

    2002-01-01

    There are few human data on low-dose-rate-radiation exposure and the consequent acute and late effects. This fact makes it difficult to assess health risks due to radiation in the space environment, especially for long-term missions. Epidemiological data on civilian flight personnel cohorts can provide information on effects due to the low-dose and low-dose rate mixed high- and low-LET radiation environment in the earth's atmosphere. The physical characteristics of the radiation environment of the atmosphere make the results of the studies of commercial flight personnel relevant to the studies of activities in space. The cooperative international effort now in progress to investigate dose reconstructions will contribute to our understanding of radiation risks for space exploration. PMID:12539781

  17. Multi-Decadal Change of Atmospheric Aerosols and their Effect on Surface Radiation

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Streets, David; Wild, Martin; Qian, Yun; Yu, Hongbin; Tan, Qian; Bian, Huisheng; Wang, Weiguo

    2011-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model, GOCART, along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007 during which a suite of aerosol data from satellite observations, ground-based measurements, and intensive field experiments have become available. Particularly: (1) We compare the model calculated clear sky downward radiation at the surface with surface network data from BSRN and CMA (2) We compare the model and surface data with satellite derived downward radiation products from ISCCP and SRS (3) We analyze the long-term global and regional aerosol trends in major anthropogenic source regions (North America, Europe, Asia) that have been experiencing considerable changes of emissions during the three decades, dust and biomass burning regions that have large interannual variability, downwind regions that are directly affected by the changes in the source area, and remote regions that are considered to representing "background" conditions. The comparisons and methods from this study can be applied to multiple model analysis in the AeroCom framework.

  18. Cloud Classes and Radiative Heating profiles at the Manus and Nauru Atmospheric Radiation Measurement (ARM) Sites

    SciTech Connect

    Mather, James H.; McFarlane, Sally A.

    2009-10-07

    The Tropical Western Pacific (TWP) is a convective regime; however, the frequency and depth of convection is dependant on dynamical forcing which exhibits variability on a range of temporal scales and also on location within the region. Manus Island, Papua New Guinea lies in the heart of the western Pacific warm pool region and exhibits frequent deep convection much of the time while Nauru, which lies approximately 20 degrees to the East of Manus, lies in a transition zone where the frequency of convection is dependent on the phase of the El Nino/Southern Oscillation. Because of this difference in dynamical regime, the distribution of clouds and the associated radiative heating is quite different at the two sites. Individual cloud types: boundary layer cumulus, thin cirrus, stratiform convective outflow, do occur at both sites – but with different frequencies. In this study we compare cloud profiles and heating profiles for specific cloud types at these two sites using data from the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF). Results of this comparison indicate that, while the frequency of specific cloud types differ between the two sites as one would expect, the characteristics of individual cloud classes are remarkably similar. This information could prove to be very useful for applying tropical ARM data to the broader region.

  19. Skill Assessment of a Spectral Ocean-Atmosphere Radiative Model

    NASA Technical Reports Server (NTRS)

    Gregg, Watson, W.; Casey, Nancy W.

    2009-01-01

    Ocean phytoplankton, detrital material, and water absorb and scatter light spectrally. The Ocean- Atmosphere Spectral Irradiance Model (OASIM) is intended to provide surface irradiance over the oceans with sufficient spectral resolution to support ocean ecology, biogeochemistry, and heat exchange investigations, and of sufficient duration to support inter-annual and decadal investigations. OASIM total surface irradiance (integrated 200 nm to 4 microns) was compared to in situ data and three publicly available global data products at monthly 1-degree resolution. OASIM spectrally-integrated surface irradiance had root mean square (RMS) difference= 20.1 W/sq m (about 11%), bias=1.6 W/sq m (about 0.8%), regression slope= 1.01 and correlation coefficient= 0.89, when compared to 2322 in situ observations. OASIM had the lowest bias of any of the global data products evaluated (ISCCP-FD, NCEP, and ISLSCP 11), and the best slope (nearest to unity). It had the second best RMS, and the third best correlation coefficient. OASIM total surface irradiance compared well with ISCCP-FD (RMS= 20.7 W/sq m; bias=-11.4 W/sq m, r=0.98) and ISLSCP II (RMS =25.2 W/sq m; bias= -13.8 W/sq m; r=0.97), but less well with NCEP (RMS =43.0 W/sq m ;bias=-22.6 W/sq m; x=0.91). Comparisons of OASIM photosynthetically available radiation (PAR) with PAR derived from SeaWiFS showed low bias (-1.8 mol photons /sq m/d, or about 5%), RMS (4.25 mol photons /sq m/d ' or about 12%), near unity slope (1.03) and high correlation coefficient (0.97). Coupled with previous estimates of clear sky spectral irradiance in OASIM (6.6% RMS at 1 nm resolution), these results suggest that OASIM provides reasonable estimates of surface broadband and spectral irradiance in the oceans, and can support studies on ocean ecosystems, carbon cycling, and heat exchange.

  20. Skill assessment of a spectral ocean-atmosphere radiative model

    NASA Astrophysics Data System (ADS)

    Gregg, Watson W.; Casey, Nancy W.

    2009-02-01

    Ocean phytoplankton, detrital material, and water absorb and scatter light spectrally. The Ocean-Atmosphere Spectral Irradiance Model (OASIM) is intended to provide surface irradiance over the oceans with sufficient spectral resolution to support ocean ecology, biogeochemistry, and heat exchange investigations, and of sufficient duration to support inter-annual and decadal investigations. OASIM total surface irradiance (integrated 200 nm to 4 μm) was compared to in situ data and three publicly available global data products at monthly 1-degree resolution. OASIM spectrally-integrated surface irradiance had root mean square (RMS) difference = 20.1 W m - 2 (about 11%), bias = 1.6 W m - 2 (about 0.8%), regression slope = 1.01 and correlation coefficient = 0.89, when compared to 2322 in situ observations. OASIM had the lowest bias of any of the global data products evaluated (ISCCP-FD, NCEP, and ISLSCP II), and the best slope (nearest to unity). It had the second best RMS, and the third best correlation coefficient. OASIM total surface irradiance compared well with ISCCP-FD (RMS = 20.7 W m - 2 ; bias = - 11.4 W m - 2 , r = 0.98) and ISLSCP II (RMS = 25.2 W m - 2 ; bias = - 13.8 W m - 2 ; r = 0.97), but less well with NCEP (RMS = 43.0 W m - 2 ; bias = - 22.6 W m - 2 ; r = 0.91). Comparisons of OASIM photosynthetically available radiation (PAR) with PAR derived from SeaWiFS showed low bias (- 1.8 mol photons m - 2 d - 1 , or about 5%), RMS (4.25 mol photons m - 2 d - 1 , or about 12%), near unity slope (1.03) and high correlation coefficient (0.97). Coupled with previous estimates of clear sky spectral irradiance in OASIM (6.6% RMS at 1 nm resolution), these results suggest that OASIM provides reasonable estimates of surface broadband and spectral irradiance in the oceans, and can support studies on ocean ecosystems, carbon cycling, and heat exchange.

  1. Measuring solar- and greenhouse radiation profiles in the atmosphere using upper-air radiosondes

    NASA Astrophysics Data System (ADS)

    Philipona, R.; Kräuchi, A.

    2012-04-01

    Solar shortwave and thermal longwave irradiance is usually measured at the Earth's surface with ground radiation stations and at the top of the atmosphere with satellites. Here we show for the first time radiative flux profiles and the radiation budget in the atmosphere measured with radiosondes ascending from the Earth's surface to 35 km into the stratosphere. During two-hour flights solar shortwave and thermal longwave irradiance, downward and upward, is measured with four individual sensors at one-second resolution, along with standard PTU radiosonde profiles. Nighttime longwave radiation measurements are contrasted to daytime measurements and 24 hours means of radiation budget- and total net radiation profiles are shown. Of particular interest for greenhouse effect investigations are in situ measured longwave greenhouse radiation profiles and their vertical changes in relation to temperature, clouds, water vapour and other greenhouse gases.

  2. 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

  3. A toy model linking atmospheric thermal radiation and sea ice growth

    NASA Technical Reports Server (NTRS)

    Thorndike, A. S.

    1992-01-01

    A simplified analytical model of sea ice growth is presented where the atmosphere is in thermal radiative equilibrium with the ice. This makes the downwelling longwave radiation reaching the ice surface an internal variable rather than a specified forcing. Analytical results demonstrate how the ice state depends on properties of the ice and on the externally specified climate.

  4. 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).

  5. Radiation-Related Risk Analysis for Atmospheric Flight Civil Aviation Flight Personnel

    NASA Technical Reports Server (NTRS)

    DeAngelis, G.; Wilson, J. W.

    2003-01-01

    Human data on low dose rate radiation exposure and consequent effects are not readily available, and this fact generates groundtruth concerns for all risk assessment techniques for possible health effects induced by the space radiation environment, especially for long term missions like those foreseen now and in the near future. A large amount of such data may be obtained through civil aviation flight personnel cohorts, in the form of epidemiological studies on delayed health effects induced by the cosmic-ray generated atmospheric radiation environment, a high- LET low dose and low dose rate ionizing radiation with its typical neutron component, to which flight personnel are exposed all throughout their work activity. In the perspective of worldwide studies on radiation exposure of the civil aviation flight personnel, all the available results from previous studies on flight personnel radiation exposure have been examined in various ways (i.e. literature review, meta-analysis) to evaluate possible significant associations between atmospheric ionizing radiation environment and health risks, and to assess directions for future investigations. The physical characteristics of the atmospheric ionizing radiation environment make the results obtained for atmospheric flight personnel relevant for space exploration.

  6. Radiative heating and cooling in the middle and lower atmosphere of Venus and responses to atmospheric and spectroscopic parameter variations

    NASA Astrophysics Data System (ADS)

    Haus, R.; Kappel, D.; Arnold, G.

    2015-11-01

    A sophisticated radiative transfer model that considers absorption, emission, and multiple scattering by gaseous and particulate constituents over the broad spectral range 0.125-1000 μm is applied to calculate radiative fluxes and temperature change rates in the middle and lower atmosphere of Venus (0-100 km). Responses of these quantities to spectroscopic and atmospheric parameter variations are examined in great detail. Spectroscopic parameter studies include the definition of an optimum spectral grid for monochromatic calculations as well as comparisons for different input data with respect to spectral line databases, continuum absorption, line shape factors, and solar irradiance spectra. Atmospheric parameter studies are based on distinct variations of an initial model data set. Analyses of actual variations of the radiative energy budget using atmospheric features that have been recently retrieved from Venus Express data will be subject of a subsequent paper. The calculated cooling (heating) rates are very reliable at altitudes below 95 (85) km with maximum uncertainties of about 0.25 K/day. Heating uncertainties may reach 3-5 K/day at 100 km. Using equivalent Planck radiation as solar insolation source in place of measured spectra is not recommended. Cooling rates strongly respond to variations of atmospheric thermal structure, while heating rates are less sensitive. The influence of mesospheric minor gas variations is small, but may become more important near the cloud base and in case of episodic SO2 boosts. Responses to cloud mode 1 particle abundance changes are weak, but variations of other mode parameters (abundances, cloud top and base altitudes) may significantly alter radiative temperature change rates up to 50% in Venus' lower mesosphere and upper troposphere. A new model for the unknown UV absorber for two altitude domains is proposed. It is not directly linked to cloud particle modes and permits an investigation of radiative effects regardless of

  7. The Atmospheric Radiation Measurement Program May 2003 Intensive Operations Period Examining Aerosol Properties and Radiative Influences: Preface to Special Section

    NASA Technical Reports Server (NTRS)

    Ferrare, Richard; Feingold, Graham; Ghan, Steven; Ogren, John; Schmid, Beat; Schwartz, Stephen E.; Sheridan, Pat

    2006-01-01

    Atmospheric aerosols influence climate by scattering and absorbing radiation in clear air (direct effects) and by serving as cloud condensation nuclei, modifying the microphysical properties of clouds, influencing radiation and precipitation development (indirect effects). Much of present uncertainty in forcing of climate change is due to uncertainty in the relations between aerosol microphysical and optical properties and their radiative influences (direct effects) and between microphysical properties and their ability to serve as cloud condensation nuclei at given supersaturations (indirect effects). This paper introduces a special section that reports on a field campaign conducted at the Department of Energy Atmospheric Radiation Measurement site in North Central Oklahoma in May, 2003, examining these relations using in situ airborne measurements and surface-, airborne-, and space-based remote sensing.

  8. Fractional integration and radiative transfer in a multifractal atmosphere

    SciTech Connect

    Naud, C.; Schertzer, D.; Lovejoy, S.

    1996-04-01

    Recently, Cess et al. (1995) and Ramathan et al. (1995) cited observations which exhibit an anomalous absorption of cloudy skies in comparison with the value predicted by usual models and which thus introduce large uncertainties for climatic change assessments. These observation raise questions concerning the way general circulation models have been tuned for decades, relying on classical methods, of both radiative transfer and dynamical modeling. The observations also tend to demonstrate that homogeneous models are simply not relevant in relating the highly variable properties of clouds and radiation fields. However smoothed, the intensity of cloud`s multi-scattered radiation fields reflect this extreme variability.

  9. Atmospheric radiation measurement program facilities newsletter, July 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-08-12

    ARM Participating in Off-site Intensive Operational Period--The ARM Program is playing a role in the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) intensive operational period (IOP), under way through July in South Florida. The objective of CRYSTAL-FACE is to investigate the physical properties and formation processes of tropical cirrus clouds. The ARM Program has deployed a suite of ground-based instruments in Florida for CRYSTAL-FACE. In addition, the National Aeronautics and Space Administration provides six research aircraft equipped with state-of-the-art instruments to measure characteristics of cirrus clouds and their ability to alter the temperature of the atmosphere. The reliability of climate predictions depends on the accuracy of computer models of climate. Interactions between clouds and solar radiation are a major source of current uncertainty in the models, hindering accurate climate prediction. A goal of CRYSTAL-FACE is to improve on the way clouds are represented in and integrated into the models and thus achieve more reliable climate predictions. CRYSTAL-FACE will be followed in 2004 by CRYSTAL-TWP, to be held at ARM's Tropical Western Pacific (TWP) location on Manus and Nauru Islands. New Storage Building Proposed for Central Facility--Now in the design phase is a new storage building to be erected at the central facility, west of the shipping and receiving trailer. The added storage is needed because shipping needs for the TWP are now being handled by the SGP site. New Seminole Extended Facility Location Approved--The extended facility formerly on the property of the Seminole Industrial Foundation had to be removed from service in April, after the land was sold to a new owner. Both the foundation and the new land owner offered options for new extended facility locations in the area. An Environmental Evaluation Notification Form has now been approved by the USDOE (ARM Program sponsor), as

  10. Atmospheric Radiation Measurement program climate research facility operations quarterly report.

    SciTech Connect

    Sisterson, D. L.; Decision and Information Sciences

    2006-09-06

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1-(ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter for the Southern Great Plains (SGP) site is 2,074.80 hours (0.95 x 2,184 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,965.60 hours (0.90 x 2,184), and that for the Tropical Western Pacific (TWP) locale is 1,856.40 hours (0.85 x 2,184). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,074.80 hours (0.95 x 2,184). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive

  11. Stochastic simulation of interaction between solar radio radiation and rarefied gas of the earth's upper atmosphere.

    NASA Astrophysics Data System (ADS)

    Marov, M. Ya.; Shematovich, V. I.; Zmievskaya, G. I.

    A numerical model is considered for the interaction between the shortwave solar radiation and the earth's upper atmosphere, which results in photoexcitation, photoionization and photodissociation processes violating thermodynamical equilibrium in a medium. The field of radiation is assumed to be equivalent to a set of photons with energies corresponding to the considered spectrum of radiation. An analogy of collisional processes in a partially ionized rarefied gas is used that leads to photochemical reactions.

  12. How Radiation Feedback Affects Fragmentation and the IMF

    NASA Astrophysics Data System (ADS)

    Krumholz, M. R.

    2011-06-01

    The stellar initial mass function (IMF) is determined by a process of fragmentation and accretion in the opaque, dense center of a giant molecular cloud. This environment effectively traps radiation from newborn stars, and the interaction between the gas and the radiation is the dominant feature controlling the thermodynamics and in some extreme cases the bulk motion of the gas. Not surprisingly, radiation feedback therefore plays a dominant role in determining how gas fragments to produce the IMF. In this contribution I focus on simulations exploring two radiative effects particularly relevant to the formation of massive stars: suppression of fragmentation by radiative heating, and interruption of accretion by radiation pressure. Contrary to past theoretical expectations, simulations show that the former is a dominant effect that may ultimately control when and where massive stars form, while the latter does not appear to have a significant effect on stellar masses.

  13. Radiative-Convective Processes in Regulating Tropical Ocean-Atmosphere

    NASA Technical Reports Server (NTRS)

    Sui, C.-H.; Lau, K.-M.; Li, X.; Ho, C.-H.

    2000-01-01

    Relationship between sea surface temperature (SST) and cloud/water vapor reveals important information about radiative-climate feedbacks. Many previous studies have found that cloud amount and SST are positively correlated for SST between 28-29.5 C, for SST greater than 29.5 C, cloud amount actually decreases with increasing SST. The breakdown of SST-cloud correlation at 29.5 C was suggested to be related to the formation of localized hot spots with very high SST due to increased solar radiation in regions of strong subsidence forced by convection elsewhere. In this study, the breakdown is related to the radiative cooling in the subsidence regime over the cold pool surrounding the warm pool. We show model and observational evidence that radiative cooling over the cold pool limits the strength of SST-induced tropical circulation. As a result, occurrence of convection is also limited when SST contrast between the warm pool and cold pool is large.

  14. Infrared radiative transfer in the dust-free Martian atmosphere

    SciTech Connect

    Crisp, D. )

    1990-08-30

    Gases in the Martian atmosphere, including CO{sub 2}, H{sub 2}O, CO, and O{sub 3}, combine to produce some absorption at most infrared wavelengths. Line-by-line and quasi-random models are used to derive synthetic spectra of dust-free Martian atmospheres. These spectra show where gases absorb most strongly and provide a baseline for comparison with the results from more complete models that include the effects of dust. Gas absorption and emission features at many infrared wavelengths provide a source of contamination that must be removed from remote sensing observations of the Martian surface. For example, the weak reflectance minimum observed at wavelengths near 2.35 {mu}m, which has been interpreted as evidence for a variety of surface materials, is produced almost entirely by atmospheric CO and CO{sub 2} absorption. Isotopic CO{sub 2} bands near 7 and 8 {mu}m and near-infrared water vapor absorption bands partially overlap strong carbonate and hydrate features and frustrate systematic spectroscopic searches for these important candidate surface materials on Mars. In other spectral regions, gas absorption bands provide opportunities to study the structure and composition of the Martian atmosphere. Computed radiances within the strong CO{sub 2} 15-{mu}m band are incorporated into an atmospheric retrieval algorithm to derive the atmospheric temperature structure from Mariner 9 IRIS observations. Absorption and emission by gases also contributes to the energetics of the Martian atmosphere. Near-infrared CO{sub 2} bands absorb enough sunlight to produce globally-averaged solar heating rates that vary from 1 K/Earth day at the surface, to 10 K/Earth day at pressures near 0.01 mbar. Other gases contribute 1-5% of the heating at some levels.

  15. Radiation-induced biological effects on crew members: a combined analysis on atmospheric flight personnel.

    PubMed

    De Angelis, G; Caldora, M; Santaquilani, M; Scipione, R; Verdecchia, A

    2001-01-01

    Human data on low dose rate radiation exposure and its effects are not readily available. A huge amount of such data may be obtained through flight personnel cohorts, in the form of epidemiological studies on delayed health effects induced by the cosmic-ray generated atmospheric ionizing radiation, to which flight personnel are exposed all throughout their work activity. All the available results from different studies on flight personnel exposure have been combined in various ways to evaluate the association between atmospheric ionizing radiation environment and health risks and to assess directions for future investigations. PMID:11771549

  16. A method for computing visible and infrared polarized monochromatic radiation in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Wauben, W. M. F.; de Haan, J. F.; Hovenier, J. W.

    1994-02-01

    In this paper we present a computational method, based on the so-called adding principle, for calculating the polarized monochromatic radiation in plane-parallel vertically inhomogeneous atmospheres. Our computer code is verified by comparing numerical results with those obtained by other investigators using different methods. We consider not only the well-known case of illumination by a unidirectional beam of light at the top of the atmosphere, but also illumination by isotropically radiating internal sources and illumination by an isotropically radiating ground surface below the atmosphere. Numerical results for all relevant Stokes parameters are tabulated for a two-layer atmosphere containing molecules and haze particles. These results pertain to the three types of illumination mentioned above. Furthermore, we describe some general features of polarized radiation in an optically thick homogeneous atmosphere containing cloud C1 water droplets. It is shown that multiple scattering of radiation in such a cloudy atmosphere may not be ignored at infrared wavelengths if molecular absorption is negligible.

  17. Radiative Forcing Effects Due to Black Carbon and Dust in the Atmosphere and Snow in the Western United States

    NASA Astrophysics Data System (ADS)

    Mao, Y.; Li, Q.; Liou, K. N.; Liao, H.; Gu, Y.; He, C.; Zhang, L.

    2014-12-01

    BC and dust are two of the most important light absorbing aerosols in the atmosphere and thus have significant direct radiative forcing and snow albedo effects regionally. There are large uncertainties in the estimates of direct radiative forcing of BC and dust, which range from 0.2 to 0.9 W m-2 for BC (Bond et al., 2013) and 0.07 to 0.31 W m-2 in the long waves for dust (IPCC, 2007). BC and dust deposited on snow can significantly reduce the surface albedos and further affect the regional hydrological cycle. In the western U.S. (WUS), mountain snowmelt accounts for over 70% of the annual fresh water supply, which is facing severe challenges in the region recently. Transpacific transport of Asian emissions is likely becoming an even larger contributor to the fine particulate matter in the WUS in spring, as the Asian emissions are increasing under the rapid economic development in this region. We thus intend to better understand the radiative forcing effects of BC and dust in the atmosphere and snow in the WUS using an offline coupled 3-D global chemical transport model with a radiative transfer model. With improved dust and BC emissions and dust particle size distributions, we would like to quantify the relative contributions from different sources and source regions to the radiative forcing of BC and dust.

  18. Atmospheric Lifetimes and Radiative Forcing of CFC-11 and CFC-12

    NASA Astrophysics Data System (ADS)

    Minschwaner, Kenneth; Hoffmann, Lars; Brown, Alex; Riese, Martin; Müller, Rolf; Bernath, Peter

    2013-03-01

    Atmospheric lifetimes for chlorofluorocarbons (CFCs) are important for interpreting their temporal trends and for evaluating their impact on stratospheric chemistry and radiative forcing of climate. The lifetimes of CFC-11 and CFC-12 have been evaluated using global observations of their stratospheric distributions from satellite-based instruments between the period 1992 and 2010. The CFC data sets are from the Cryogen Limb Array Etalon Spectrometer (CLAES), the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA-1 and CRISTA-2), the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), and the Atmospheric Chemistry Experiment (ACE). Stratospheric loss rates were calculated using an ultraviolet radiative transfer code with updated molecular cross section and solar irradiance data. Infrared radiative forcings (net flux changes at the tropopause) were determined using CFC distributions from the satellite observations.

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  20. Radiative transfer solutions for coupled atmosphere ocean systems using the matrix operator technique

    NASA Astrophysics Data System (ADS)

    Hollstein, André; Fischer, Jürgen

    2012-05-01

    Accurate radiative transfer models are the key tools for the understanding of radiative transfer processes in the atmosphere and ocean, and for the development of remote sensing algorithms. The widely used scalar approximation of radiative transfer can lead to errors in calculated top of atmosphere radiances. We show results with errors in the order of±8% for atmosphere ocean systems with case one waters. Variations in sea water salinity and temperature can lead to variations in the signal of similar magnitude. Therefore, we enhanced our scalar radiative transfer model MOMO, which is in use at Freie Universität Berlin, to treat these effects as accurately as possible. We describe our one-dimensional vector radiative transfer model for an atmosphere ocean system with a rough interface. We describe the matrix operator scheme and the bio-optical model for case one waters. We discuss some effects of neglecting polarization in radiative transfer calculations and effects of salinity changes for top of atmosphere radiances. Results are shown for the channels of the satellite instruments MERIS and OLCI from 412.5 nm to 900 nm.

  1. The effect of cumulus cloud field anisotropy on solar radiative fluxes and atmospheric heating rates

    NASA Astrophysics Data System (ADS)

    Hinkelman, Laura M.

    The effect of fair-weather cumulus cloud field anisotropy on domain average surface fluxes and atmospheric heating profiles was studied. Causes of anisotropy were investigated using a large-eddy simulation (LES) model. Cloud formation under a variety of environmental conditions was simulated and the degree of anisotropy in the output fields was calculated. Wind shear was found to be the single greatest factor in the development of both vertically tilted and horizontally stretched cloud structures. A stochastic field generation algorithm was used to produce twenty three-dimensional liquid water content fields based on the statistical properties of the LES cloud scenes. Progressively greater degrees of tilt and stretching were imposed on each of these scenes, so that an ensemble of scenes were produced for each level of distortion. The resulting scenes were used as input to a three-dimensional Monte Carlo model. Domain-average transmission, reflection, and absorption of broadband solar radiation were computed for each scene along with the average heating rate profile. Both tilt and horizontal stretching were found to significantly affect calculated fluxes, with the amount and sign of flux differences depending strongly on sun position relative to cloud distortion geometry. For nearly all solar geometries, domain-averaged fluxes and atmospheric heating rate profiles calculated using the Independent Pixel Approximation differed substantially from the corresponding three-dimensional Monte Carlo results.

  2. A Consummate Radiative Transfer Package for Studying the Atmosphere and Oceans

    NASA Astrophysics Data System (ADS)

    Zhai, P.; Hu, Y.; Trepte, C. R.; Winker, D. M.

    2015-12-01

    We will present a radiative transfer package based on the successive order of scattering method. This code is capable to calculate the radiation field in turbid media, which can be either the atmosphere-land or atmosphere-ocean coupled systems. The outputs include all four Stokes parameters at arbitrary detector locations and viewing angles in the turbid medium. Both the elastic and inelastic scattering are implemented in the package. This radiative transfer tool has been used in various applications, for instance, generating an aerosol look-up table for atmospheric correction in ocean color remote sensing; retrieving water cloud size distribution using the polarized multi-angle measurements; simulating the OCO2 O2 A band radiance measurement, etc. Our radiative transfer package is a great tool to interpret and predict the measurements from the future polarimeters and multipolarization-state lidars for Earth observing missions.

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

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  4. Radiative transfer in real atmospheres. [the implications for recognition processing of multispectral remote sensing data

    NASA Technical Reports Server (NTRS)

    Turner, R. E.

    1974-01-01

    The problem of multiple radiation scattering in an atmosphere characterized by various amounts of aerosol absorption and different particle size distributions was investigated. The visible part of the spectrum was emphasized, including the effect of ozone absorption. An atmosphere bounded by a nonhomogenous, Lambertian surface was also studied, along with the effect of background radiation on target in terms of various atmopheric and geometric conditions. Results of the investigation indicate that comtaminated atmospheres can change the radiation field by a considerable amount, and that the effect of non-uniform surface significantly alters the intrinsic radiation from a target element. The implications of these results for the recognition processing of multispectral remote sensing data is discussed.

  5. Atmospheric Radiation Measurement Program facilities newsletter, September 2000

    SciTech Connect

    Sisterson, D. L.; Holdridge, D. J., ed.

    2000-09-19

    This is the third water vapor IOP and it will focus on the lower portions of the atmosphere. Again, scientists will work to achieve absolute calibrations of water vapor instrumentation. For this purpose, several instruments will be deployed, and measurements will be compared. Instruments to be used include radiosondes, Raman lidar, chilled-mirror hygrometers, surface meteorological observation station (SMOS) towers, a variety of microwave radiometers, and global positioning systems (GPS). The current experiment has two goals. The first is to characterize the accuracy of the water vapor measurements, especially the daily operational observations being made around the clock in the lower levels of the atmosphere at the CART site. The second goal is to develop techniques for improving the accuracy of these observations in order to obtain the best possible water vapor measurements under a wide range of atmospheric conditions.

  6. Multi-Decadal Change of Atmospheric Aerosols and their Effects on Surface Radiation

    NASA Technical Reports Server (NTRS)

    Chin, Mian

    2011-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007) during which a suite of aerosol data from satellite observations) ground-based measurements) and intensive field experiments have become available. We analyze the long-term global and regional aerosol trends and their relationship to the changes of aerosol and precursor emissions and assess the role aerosols play in the multi-decadal change of solar radiation reaching the surface (known as "dimming" or "brightening") at different regions of the world) including the major anthropogenic source regions (North America) Europe) Asia) that have been experiencing considerable changes of emissions) dust and biomass burning regions that have large interannual variabilities) downwind regions that are directly affected by the changes in the source area) and remote regions that are considered to representing "backgroundH conditions.

  7. Multi-Decadal Change of Atmospheric Aerosols and Their Effect on Surface Radiation

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Tan, Qian; Wild, Martin; Qian, Yun; Yu, Hongbin; Bian, Huisheng; Wang, Weiguo

    2012-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007, during which a suite of aerosol data from satellite observations and ground-based remote sensing and in-situ measurements have become available. We analyze the long-term global and regional aerosol optical depth and concentration trends and their relationship to the changes of emissions" and assess the role aerosols play in the multi-decadal change of solar radiation reaching the surface (known as "dimming" or "brightening") at different regions of the world, including the major anthropogenic source regions (North America, Europe, Asia) that have been experiencing considerable changes of emissions, dust and biomass burning regions that have large interannual variabilities, downwind regions that are directly affected by the changes in the source area, and remote regions that are considered to representing "background" conditions.

  8. An analytic radiative transfer model for a coupled atmosphere and leaf canopy

    NASA Technical Reports Server (NTRS)

    Liang, Shunlin; Strahler, Alan H.

    1995-01-01

    A new analytical radiative transfer model of a leaf canopy is developed that approximates multiple-scattering radiance by a four-stream formulation. The canopy model is coupled to a homogeneous atmospheric model as well as a non-Lambertian lower boundary soil surface. The same four-stream formulation is also used for the calculation of multiple scattering in the atmosphere. Comparisons of radiance derived from the four-stream model with those calculated by an iterative numerical solution of the radiative transfer equation show that the analytic model has a very high accuracy, even with a turbid atmosphere and a very dense canopy in which multiple scattering dominates. Because the coupling of canopy and atmospheric models fully accommodates anisotropic surface reflectance and atmospheric scattering and its effect on directional radiance, the model is especially useful for application to directional radiance and measurements obtained by remote sensing. Retrieval of biophysical parameters using this model is under investigation.

  9. Vertical profiles of BC direct radiative effect over Italy: high vertical resolution data and atmospheric feedbacks

    NASA Astrophysics Data System (ADS)

    Močnik, Griša; Ferrero, Luca; Castelli, Mariapina; Ferrini, Barbara S.; Moscatelli, Marco; Grazia Perrone, Maria; Sangiorgi, Giorgia; Rovelli, Grazia; D'Angelo, Luca; Moroni, Beatrice; Scardazza, Francesco; Bolzacchini, Ezio; Petitta, Marcello; Cappelletti, David

    2016-04-01

    Black carbon (BC), and its vertical distribution, affects the climate. Global measurements of BC vertical profiles are lacking to support climate change research. To fill this gap, a campaign was conducted over three Italian basin valleys, Terni Valley (Appennines), Po Valley and Passiria Valley (Alps), to characterize the impact of BC on the radiative budget under similar orographic conditions. 120 vertical profiles were measured in winter 2010. The BC vertical profiles, together with aerosol size distribution, aerosol chemistry and meteorological parameters, have been determined using a tethered balloon-based platform equipped with: a micro-Aethalometer AE51 (Magee Scientific), a 1.107 Grimm OPC (0.25-32 μm, 31 size classes), a cascade impactor (Siuotas SKC), and a meteorological station (LSI-Lastem). The aerosol chemical composition was determined from collected PM2.5 samples. The aerosol absorption along the vertical profiles was measured and optical properties calculated using the Mie theory applied to the aerosol size distribution. The aerosol optical properties were validated with AERONET data and then used as inputs to the radiative transfer model libRadtran. Vertical profiles of the aerosol direct radiative effect, the related atmospheric absorption and the heating rate were calculated. Vertical profile measurements revealed some common behaviors over the studied basin valleys. From below the mixing height to above it, a marked concentration drop was found for both BC (from -48.4±5.3% up to -69.1±5.5%) and aerosol number concentration (from -23.9±4.3% up to -46.5±7.3%). These features reflected on the optical properties of the aerosol. Absorption and scattering coefficients decreased from below the MH to above it (babs from -47.6±2.5% up to -71.3±3.0% and bsca from -23.5±0.8% up to -61.2±3.1%, respectively). Consequently, the Single Scattering Albedo increased above the MH (from +4.9±2.2% to +7.4±1.0%). The highest aerosol absorption was

  10. Radiative transfer in CO2-rich atmospheres: 1. Collisional line mixing implies a colder early Mars

    NASA Astrophysics Data System (ADS)

    Ozak, N.; Aharonson, O.; Halevy, I.

    2016-06-01

    Fast and accurate radiative transfer methods are essential for modeling CO2-rich atmospheres, relevant to the climate of early Earth and Mars, present-day Venus, and some exoplanets. Although such models already exist, their accuracy may be improved as better theoretical and experimental constraints become available. Here we develop a unidimensional radiative transfer code for CO2-rich atmospheres, using the correlated k approach and with a focus on modeling early Mars. Our model differs from existing models in that it includes the effects of CO2 collisional line mixing in the calculation of the line-by-line absorption coefficients. Inclusion of these effects results in model atmospheres that are more transparent to infrared radiation and, therefore, in colder surface temperatures at radiative-convective equilibrium, compared with results of previous studies. Inclusion of water vapor in the model atmosphere results in negligible warming due to the low atmospheric temperatures under a weaker early Sun, which translate into climatically unimportant concentrations of water vapor. Overall, the results imply that sustained warmth on early Mars would not have been possible with an atmosphere containing only CO2 and water vapor, suggesting that other components of the early Martian climate system are missing from current models or that warm conditions were not long lived.

  11. Reports of workshops on Probe Measurements of Particles and Radiation in the Atmosphere of Titan

    NASA Technical Reports Server (NTRS)

    Ragent, Boris (Compiler); Swenson, Byron L. (Compiler)

    1990-01-01

    The planned 1995 joint ESA-NASA Cassini mission to the Saturnian system will include an atmospheric probe to be dropped into the atmosphere of Titan for in situ measurements during descent. Because of the unique properties of the Titan atmosphere it is necessary to consider the peculiar requirements for such measurements and applicable techniques. The proceedings of two workshops dealing with the measurement of particles and radiation in the atmosphere of Titan are presented in two parts. The first part dealt with the measurement of particulate matter in the atmosphere of Titan. The second part dealt with the measurement of radiation in the atmosphere of Titan. The proceedings were first published and distributed informally, and are presented with only minor editorial changes. In the report of the particulate matter workshop, discussions of the mission background, the importance of the measurements, and descriptions of the desired information are followed by a description of appropriate measurement techniques and conclusions and recommendations. The proceeding for the workshop on radiation measurement and imaging contains a discussion of the importance of radiation measurements and imaging, and presents a summary of participants' experience with such measurements made from entry probes. This is followed by a description of appropriate measurement techniques and conclusions and recommendations.

  12. Site/Systems Operations, Maintenance and Facilities Management of the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site

    SciTech Connect

    Wu, Susan

    2005-08-01

    This contract covered the site/systems operations, maintenance, and facilities management of the DOE Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site.

  13. Infrared radiation and inversion population of CO2 laser levels in Venusian and Martian atmospheres

    NASA Technical Reports Server (NTRS)

    Gordiyets, B. F.; Panchenko, V. Y.

    1983-01-01

    Formation mechanisms of nonequilibrium 10 micron CO2 molecule radiation and the possible existence of a natural laser effect in the upper atmospheres of Venus and Mars are theoretically studied. An analysis is made of the excitation process of CO2 molecule vibrational-band levels (with natural isotropic content) induced by direct solar radiation in bands 10.6, 9.4, 4.3, 2.7 and 2.0 microns. The model of partial vibrational-band temperatures was used in the case. The problem of IR radiation transfer in vibrational-rotational bands was solved in the radiation escape approximation.

  14. Net thermal radiation in the atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Revercomb, H. E.; Sromovsky, L. A.; Suomi, V. E.; Boese, R. W.

    1985-01-01

    Estimates of the true atmospheric net fluxes at the four Pioneer Venus entry sites are presently obtained through corrections of measured values that are relatively small for the case of the clouds, but generally large deeper in the atmosphere. The correction procedure for both the small and large probe fluxes used model results near 14 km to establish the size of the correction. The thermal net fluxes obtained imply that the contribution of mode 3 particles to the IR opacity of the middle and lower clouds is smaller than indicated by the Pioneer Venus cloud particle spectrometer measurements, and the day probe results favor a reduction of only about 50 percent. The fluxes at all sites imply that a yet-undetermined source of considerable opacity is present in the upper cloud. Beneath the clouds, the thermal net fluxes generally increase with increasing latitude.

  15. Return glider radiosonde to measure temperature, humidity and radiation profiles through the atmosphere

    NASA Astrophysics Data System (ADS)

    Kraeuchi, Andreas; Philipona, Rolf

    2015-04-01

    Very promising radiation profile measurements through the atmosphere were made in 2011 with a balloon borne short- and longwave net radiometer. New and improved radiation sensors from Kipp&Zonen are now used in a glider aircraft together with a standard Swiss radiosonde from Meteolabor AG. This new return glider radiosonde (RG-R), is lifted up with double balloon technique to prevent pendulum motion and to keep the radiation instruments as horizontal as possible during the ascent measuring phase. The RG-R is equipped with a mechanism that allows to release the radiosonde at a preset altitude, and an autopilot allowing to fly the radiosonde back to the launch site and to land it savely with a parachute at a preset location. The return glider radiosonde technique as well as new measurement possibilities will be shown. First measurements show temperature, humidity and radiation profiles through the atmosphere up to 30 hPa (24 km) during different atmospheric conditions. Radiation profiles during different daytimes show possibilities with respect to temporal resolution of vertical radiation profiles trough the atmosphere.

  16. Female reproductive function in areas affected by radiation after the Chernobyl power station accident

    SciTech Connect

    Kulakov, V.I.; Sokur, T.N.; Volobuev, A.I.

    1993-07-01

    This paper reports the results of a comprehensive survey of the effects of the accidental release of radiation caused by the accident at the Chernobyl nuclear power station in April 1986. The accident and the resulting release of radiation and radioactive products into the atmosphere produced the most serious environmental contamination so far recorded. We have concentrated on evaluating the outcomes and health risks to women, their reproductive situation, and consequences for their progeny. We have concentrated on two well-defined areas: the Chechersky district of the Gomel region in Belorussia and the Polessky district of the Kiev region in the Ukraine. A number of investigations were carried out on 688 pregnant women and their babies, and data were obtained from 7000 labor histories of the development of newborns for a period of 8 years (3 years before the accident and 5 years after it). Parameters examined included birth rate, thyroid pathology, extragenital pathology such as anemias, renal disorders, hypertension, and abnormalities in the metabolism of fats, complications of gestation, spontaneous abortions, premature deliveries, perinatal morbidity and mortality, stillbirths and early neonatal mortality, infections and inflammatory diseases, neurological symptoms and hemic disturbances in both mothers and infants, trophic anomalies, and biochemical and structural changes in the placenta. Several exogenous, complicating influences were also considered such as psycho-emotional factors, stress, lifestyle changes, and others caused directly by the hazardous situation and by its consequences such as treatment, removal from affected areas, etc. 9 figs.

  17. The Chandrasekhar method and its applications to atmospheric radiative transfer

    SciTech Connect

    Stamnes, K.

    1994-12-31

    Problems involving radiation and particle transport in a host medium require solution of the linear (or linearized) Boltzmann equation. A convenient strategy for solving such problems is to apply a multigroup procedure in which the problem is reformulated as a series of one-group problems in such a way that each one-group problem may be cast into a form identical to the monochromatic radiative transfer equation. In essence, Chandrasekhar`s method consists of converting the integro-differential equation for the resulting one-group problem into a system of coupled differential equations for which eigensolutions are sought. The basic method is well described in Chandrasekhar`s classic text in which applications to simple problems were used to demonstrate the potential power of the method before the advent of the modern computer.

  18. Atmospheric Radiation Measurement program facilities newsletter, May 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-06-03

    Eight eddy correlation (ECOR) flux measurement systems are now deployed throughout the ARM SGP CART site. These systems are used to determine the flux (flow) of sensible heat, the flux of latent heat, and air momentum just above cropland a few hundred feet upwind of the ECOR locations. Sensible heat is energy we feel as warmth. Latent heat is the energy that evaporated water vapor measured in the atmosphere. The ECOR systems actually measure wind velocity and temperature fluctuations, water vapor, and barometric pressure. The surface flux values for sensible heat, latent heat, and momentum are calculated from these measurements.

  19. Overview of the United States Department of Energy's ARM (Atmospheric Radiation Measurement) Program

    SciTech Connect

    Stokes, G.M. ); Tichler, J.L. )

    1990-06-01

    The Department of Energy (DOE) is initiating a major atmospheric research effort, the Atmospheric Radiation Measurement Program (ARM). The program is a key component of DOE's research strategy to address global climate change and is a direct continuation of DOE's decade-long effort to improve the ability of General Circulation Models (GCMs) to provide reliable simulations of regional, and long-term climate change in response to increasing greenhouse gases. The effort is multi-disciplinary and multi-agency, involving universities, private research organizations and more than a dozen government laboratories. The objective of the ARM Research is to provide an experimental testbed for the study of important atmospheric effects, particularly cloud and radiative processes, and to test parameterizations of these processes for use in atmospheric models. This effort will support the continued and rapid improvement of GCM predictive capability. 2 refs.

  20. Atmospheric Radiation Measurement Program facilities newsletter, February 2001.

    SciTech Connect

    Holdridge, D. J.

    2001-03-08

    This newsletter consists of the following: (1) ARM Science Team Meeting Scheduled--The 11th Annual ARM Science Team meeting is scheduled for March 19-23, 2001, in Atlanta, Georgia. Members of the science team will exchange research results achieved by using ARM data. The science team is composed of working groups that investigate four topics: instantaneous radiative flux, cloud parameterizations and modeling, cloud properties, and aerosols. The annual meeting brings together the science team's 150 members to discuss issues related to ARM and its research. The members represent universities, government laboratories and research facilities, and independent research companies. (2) Communications to Extended Facilities Upgraded--New communications equipment has been installed at all of the SGP extended facilities. Shelters were installed to house the new equipment used to transfer data from instruments via the Internet to the site data system at the central facility. This upgrade has improved data availability from the extended facilities to 100% and reduced telephone costs greatly. (3) SGP Goes ''Buggy''--Steve Sekelsky, a researcher from the University of Massachusetts, is planning to bring a 95-GHz radar to the SGP central facility for deployment in March-October 2001. The radar will help to identify signals due to insects flying in the air. The ARM millimeter cloud radar, which operates at 35 GHz, is sensitive to such insect interference. Testing will also be performed by using a second 35-GHz radar with a polarized radar beam, which can differentiate signals from insects versus cloud droplets. (4) Winter Fog--Fog can add to hazards already associated with winter weather. Common types of fog formation include advection, radiation, and steam. Advection fog: An advection fog is a dense fog that forms when a warm, moist air mass moves into an area with cooler ground below. For example, fog can form in winter when warmer, water-saturated air from the south (associated

  1. Atmospheric Radiation Measurement program facilities newsletter, April 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-04-29

    The National Oceanic and Atmospheric Administration (NOAA) recently announced the development of El Nino conditions in the tropical Pacific Ocean near the South American coastline. Scientists detected a 4 F increase in the sea-surface temperatures during February. Conrad C. Lautenbacher, NOAA administrator and Under Secretary of Commerce for Oceans and Atmosphere, indicated that this warming is a sign that the Pacific Ocean is heading toward an El Nino condition. Although it is too early to predict how strong the El Nino will become or the conditions it will bring to the United States, Lautenbacher said that the country is likely to feel the effects as soon as midsummer (Figure 1). During the last El Nino in 1997-1998, the United States experienced strong weather impacts. Even though researchers don't understand what causes the onset of El Nino, they do recognize what to expect once development has begun. Scientists can monitor the development of El Nino through NOAA's advanced global climate monitoring system of polar-orbiting satellites and 72 ocean buoys moored across the equator in the Pacific Ocean. The resulting measurements of surface meteorological parameters and upper ocean temperatures are made available to scientists on a real-time basis, allowing for timely monitoring and predictions. This complex monitoring array enabled NOAA to predict the 1997-1998 El Nino six months in advance.

  2. A Thermal Infrared Radiation Parameterization for Atmospheric Studies

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah; Suarez, Max J.; Liang, Xin-Zhong; Yan, Michael M.-H.; Cote, Charles (Technical Monitor)

    2001-01-01

    This technical memorandum documents the longwave radiation parameterization developed at the Climate and Radiation Branch, NASA Goddard Space Flight Center, for a wide variety of weather and climate applications. Based on the 1996-version of the Air Force Geophysical Laboratory HITRAN data, the parameterization includes the absorption due to major gaseous absorption (water vapor, CO2, O3) and most of the minor trace gases (N2O, CH4, CFCs), as well as clouds and aerosols. The thermal infrared spectrum is divided into nine bands. To achieve a high degree of accuracy and speed, various approaches of computing the transmission function are applied to different spectral bands and gases. The gaseous transmission function is computed either using the k-distribution method or the table look-up method. To include the effect of scattering due to clouds and aerosols, the optical thickness is scaled by the single-scattering albedo and asymmetry factor. The parameterization can accurately compute fluxes to within 1% of the high spectral-resolution line-by-line calculations. The cooling rate can be accurately computed in the region extending from the surface to the 0.01-hPa level.

  3. Atmospheric Ionizing Radiation (AIR): Analysis, Results, and Lessons Learned From the June 1997 ER-2 Campaign

    NASA Technical Reports Server (NTRS)

    Wilson, J. W. (Editor); Jones, I. W. (Editor); Maiden, D. L. (Editor); Goldhagen, P. (Editor)

    2003-01-01

    The United States initiated a program to assess the technology required for an environmentally safe and operationally efficient High Speed Civil Transport (HSCT) for entrance on the world market after the turn of the century. Due to the changing regulations on radiation exposures and the growing concerns over uncertainty in our knowledge of atmospheric radiations, the NASA High Speed Research Project Office (HSRPO) commissioned a review of "Radiation Exposure and High-Altitude Flight" by the National Council on Radiation Protection and Measurements (NCRP). On the basis of the NCRP recommendations, the HSRPO funded a flight experiment to resolve the environmental uncertainty in the atmospheric ionizing radiation levels as a step in developing an approach to minimize the radiation impact on HSCT operations. To minimize costs in this project, an international investigator approach was taken to assure coverage with instrument sensitivity across the range of particle types and energies to allow unique characterization of the diverse radiation components. The present workshop is a result of the flight measurements made at the maximum intensity of the solar cycle modulated background radiation levels during the month of June 1997.

  4. An Introduction to Atmospheric Radiation: Review for the Bulletin of AMS

    NASA Technical Reports Server (NTRS)

    Marshak, Alexander

    2003-01-01

    Whether you like a certain geophysical book or not, largely depends on your background. The field of radiative transfer and atmospheric radiation, in particular, combines people with a wide range of mathematical skills: from theoretical astrophysicists and nuclear physicists to meteorologists and ecologists. There is always a delicate balance between physical explanations and their mathematical interpretations. This balance is very personal and is based on your background. I came to the field of atmospheric radiative transfer as a mathematician with little knowledge of atmospheric physics. After being in the field for more than a decade, I still have gaps in my atmospheric science education. Thus I assess a radiative transfer book fi-om two main criteria: how well does it describe the material that is familiar to me (the radiative transfer equation and its numerical solutions) and how well does it help me to fill the gaps in my personal knowledge. So I present this review fi-om the perspective of a former mathematician working in the field of atmospheric radiation. . After being asked to review the book, my first intention was to compare the new edition with the previous one (Liou, 1980). In doing so, you can clearly follow the progress made in the field of atmospheric radiation over the past two decades. If there are few changes (as in Fundamental Radiative Transfer) or no changes at all (as in the Maxwell s equations), then the field has not seen much development. To the contrary, many differences between the two editions illustrate areas of major progress in the field, such as evidenced in Thermal Ineared Radiative Transfer and even in the creations of completely new fields like Three-Dimensional Radiative Transfer or Light Scattering by Nonspherical Particles. Obviously, the major changes happened not in the theory, which is at least half a century old, but in data quality and completely new measurements (mostly due to new satellite data) with higher accuracy

  5. An Analytical Solution of Radiative Transfer in the Coupled Atmosphere-Ocean System with Rough Surface

    NASA Technical Reports Server (NTRS)

    Jin, Zhonghai; Charlock, Thomas P.; Rutledge, Ken; Knut Stamnes; Wang, Yingjian

    2006-01-01

    Using the efficient discrete-ordinate method, we present an analytical solution for radiative transfer in the coupled atmosphere-ocean system with rough air-water interface. The theoretical formulations of the radiative transfer equation and solution are described. The effects of surface roughness on radiation field in the atmosphere and ocean are studied and compared with measurements. The results show that ocean surface roughness has significant effects on the upwelling radiation in the atmosphere and the downwelling radiation in the ocean. As wind speed increases, the angular domain of sunglint broadens, the surface albedo decreases, and the transmission to ocean increases. The downward radiance field in the upper ocean is highly anisotropic, but this anisotropy decreases rapidly as surface wind increases and as depth in ocean increases. The effects of surface roughness on radiation also depend greatly on both wavelength and angle of incidence (i.e., solar elevation); these effects are significantly smaller throughout the spectrum at high sun. The model-observation discrepancies may indicate that the Cox-Munk surface roughness model is not sufficient for high wind conditions.

  6. Radiation Budget Profiles measured through the Atmosphere with a Return Glider Radiosonde

    NASA Astrophysics Data System (ADS)

    Philipona, R.; Kraeuchi, A.; Kivi, R.

    2015-12-01

    Very promising radiation budget profile measurements through the atmosphere were made in 2011 with a balloon borne short- and longwave net radiometer. New and improved radiation sensors from Kipp&Zonen are now used in a glider aircraft together with a standard Swiss radiosonde from Meteolabor AG. This new return glider radiosonde (RG-R), is lifted up with double balloon technique to prevent pendulum motion and to keep the radiation instruments as horizontal as possible during the ascent measuring phase. The RG-R is equipped with a release mechanism and an autopilot that flies the glider radiosonde back to the launch site, or to a predefined open space, where it releases a parachute for landing once it is 100 meter above ground. The RG-R was successfully tested and deployed for tropospheric and stratospheric radiation measurements up to 30 hPa (24 km altitude) at the GRUAN sites Payerne (Switzerland) and Sodankylä (Finland). Radiation profiles and the radiation budget through the atmosphere during different daytimes and under cloud-free and cloudy situations will be shown in relation to temperature and humidity at the surface and in the atmosphere. The RG-R flight characteristics and new measurement possibilities will also be discussed.

  7. Ultraviolet radiation affects emission of ozone-depleting substances by marine macroalgae: results from a laboratory incubation study.

    PubMed

    Laturnus, Frank; Svensson, Teresia; Wiencke, Christian; Oberg, Gunilla

    2004-12-15

    The depletion of stratospheric ozone due to the effects of ozone-depleting substances, such as volatile organohalogens, emitted into the atmosphere from industrial and natural sources has increased the amount of ultraviolet radiation reaching the earth's surface. Especially in the subpolar and polar regions, where stratospheric ozone destruction is the highest, individual organisms and whole ecosystems can be affected. In a laboratory study, several species of marine macroalgae occurring in the polar and northern temperate regions were exposed to elevated levels of ultraviolet radiation. Most of the macroalgae released significantly more chloroform, bromoform, dibromomethane, and methyl iodide-all volatile organohalogens. Calculating on the basis of the release of total chlorine, bromine, and iodine revealed that, except for two macroalgae emitting chlorine and one alga emitting iodine, exposure to ultraviolet radiation caused macroalgae to emit significantly more total chlorine, bromine, and iodine. Increasing levels of ultraviolet radiation due to possible further destruction of the stratospheric ozone layer as a result of ongoing global atmospheric warming may thus increase the future importance of marine macroalgae as a source for the global occurrence of reactive halogen-containing compounds.

  8. Atmospheric Radiation Measurement (ARM) Data from Point Reyes, California for the Marine Stratus, Radiation, Aerosol, and Drizzle (MASRAD) Project

    DOE Data Explorer

    Point Reyes National Seashore, on the California coast north of San Francisco, was the location of the first deployment of the DOE's Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF). The ARM Program collaborated with the U.S. Office of Naval Research and DOE's Aerosol Science Program in the Marine Stratus, Radiation, Aerosol, and Drizzle (MASRAD) project. Their objectives were to collect data from cloud/aerosol interactions and to improve understanding of cloud organization that is often associated with patches of drizzle. Between March and September 2005, the AMF and at least two research aircraft were used to collect data.

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

    PubMed

    Flamm, E J; Lingenfelter, R E

    1964-06-26

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

  10. Black Carbon Vertical Profiles Strongly Affect Its Radiative Forcing Uncertainty

    NASA Technical Reports Server (NTRS)

    Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, S.; Berntsen, T. K.; Bian, H.; Bellouin, N.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kinne, S.; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2013-01-01

    The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

  11. Black Carbon Vertical Profiles Strongly Affect its Radiative Forcing Uncertainty

    SciTech Connect

    Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, Susanne E.; Berntsen, T.; Bian, Huisheng; Bellouin, N.; Diehl, T.; Easter, Richard C.; Ghan, Steven J.; Iversen, T.; Kinne, Stefan; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, Xiaohong; Penner, Joyce E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, Kai

    2013-03-01

    The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

  12. Atmospheric Ionizing Radiation and the High Speed Civil Transport. Chapter 1

    NASA Technical Reports Server (NTRS)

    Maiden, D. L.; Wilson, J. W.; Jones, I. W.; Goldhagen, P.

    2003-01-01

    Atmospheric ionizing radiation is produced by extraterrestrial radiations incident on the Earth's atmosphere. These extraterrestrial radiations are of two sources: ever present galactic cosmic rays with origin outside the solar system and transient solar particle events that are at times very intense events associated with solar activity lasting several hours to a few days. Although the galactic radiation penetrating through the atmosphere to the ground is low in intensity, the intensity is more than two orders of magnitude greater at commercial aircraft altitudes. The radiation levels at the higher altitudes of the High Speed Civil Transport (HSCT) are an additional factor of two higher. Ionizing radiation produces chemically active radicals in biological tissues that alter the cell function or result in cell death. Protection standards against low levels of ionizing radiation are based on limitation of excess cancer mortality or limitation of developmental injury resulting in permanent damage to the offspring during pregnancy. The crews of commercial air transport operations are considered as radiation workers by the EPA, the FAA, and the International Commission on Radiological Protection (ICRP). The annual exposures of aircrews depend on the latitudes and altitudes of operation and flight time. Flight hours have significantly increased since deregulation of the airline industry in the 1980's. The FAA estimates annual subsonic aircrew exposures to range from 0.2 to 9.1 mSv compared to 0.5 mSv exposure of the average nuclear power plant worker in the nuclear industry. The commercial aircrews of the HSCT may receive exposures above recently recommended allowable limits for even radiation workers if flying their allowable number of flight hours. An adequate protection philosophy for background exposures in HSCT commercial airtraffic cannot be developed at this time due to current uncertainty in environmental levels. In addition, if a large solar particle event

  13. Observations of the impact of a major Saharan dust storm on the atmospheric radiation balance

    SciTech Connect

    Slingo, A.; Ackerman, Thomas P.; Allan, R. P.; Kassianov, Evgueni I.; McFarlane, Sally A.; Robinson, G. J.; Barnard, James C.; Miller, Mark; Harries, J. E.; Russell, J. E.; Dewitte, S.

    2006-12-01

    Saharan dust storms transport large quantities of material across the African continent and beyond, causing widespread disruption and hazards to health. The dust may be deposited into the Atlantic Ocean, where it provides an important source of nutrients1, and may be carried as far as the West Indies. Such events may also influence the growth of Atlantic tropical cyclones. Satellite observations have enabled estimates to be made of the effect of the dust on the radiation budget seen from space, but only limited in situ observations have hitherto been made at the surface. Here we present the first simultaneous and continuous observations of the effect of a major dust storm in March 2006 on the radiation budget both at the top of the atmosphere (TOA) and at the surface. We combine data from the Geostationary Earth Radiation Budget (GERB) broadband radiometer and the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) on the Meteosat-8 weather satellite with remote sensing and in situ measurements from a new Mobile Facility located in Niamey, Niger (13{sup o} 29'N, 2{sup o} 10'E), operated by the US Atmospheric Radiation Measurement (ARM) program. We show that the dust produced major perturbations to the radiation budget seen from space and from the surface. By combining the two datasets, we estimate the impact on the radiation budget of the atmosphere itself. Using independent data from the Mobile Facility, we derive the optical properties of the dust and input these and other information into radiation codes to simulate the radiative fluxes. Comparisons with the observed fluxes provides a stringent test of the ability of the codes to represent the radiative properties of this important component of the global aerosol burden.

  14. Atmospheric Deposition of Heavy Metals in Soil Affected by Different Soil Uses of Southern Spain

    NASA Astrophysics Data System (ADS)

    Acosta, J. A.; Faz, A.; Martínez-Martínez, S.; Bech, J.

    2009-04-01

    Heavy metals are a natural constituent of rocks, sediments and soils. However, the heavy metal content of top soils is also dependent on other sources than weathering of the indigenous minerals; input from atmospheric deposition seems to be an important pathway. Atmospheric deposition is defined as the process by which atmospheric pollutants are transferred to terrestrial and aquatic surfaces and is commonly classified as either dry or wet. The interest in atmospheric deposition has increased over the past decade due to concerns about the effects of deposited materials on the environment. Dry deposition provides a significant mechanism for the removal of particles from the atmosphere and is an important pathway for the loading of heavy metals into the soil ecosystem. Within the last decade, an intensive effort has been made to determine the atmospheric heavy metal deposition in both urban and rural areas. The main objective of this study was to identification of atmospheric heavy metals deposition in soil affected by different soil uses. Study area is located in Murcia Province (southeast of Spain), in the surroundings of Murcia City. The climate is typically semiarid Mediterranean with an annual average temperature of 18°C and precipitation of 350 mm. In order to determine heavy metals atmospheric deposition a sampling at different depths (0-1 cm, 1-5 cm, 5-15 cm and 15-30 cm) was carried out in 7 sites including agricultural soils, two industrial areas and natural sites. The samples were taken to the laboratory where, dried, passed through a 2 mm sieve, and grinded. For the determination of the moisture the samples were weighed and oven dried at 105 °C for 24 h. The total amounts of metals (Pb, Cu, Pb, Zn, Cd, Mn, Ni and Cr) were determined by digesting the samples with nitric/perchoric acids and measuring with ICP-MS. Results showed that zinc contamination in some samples of industrial areas was detected, even this contamination reaches 30 cm depth; thus it is

  15. Angular radiation models for Earth-atmosphere system. Volume 1: Shortwave radiation

    NASA Technical Reports Server (NTRS)

    Suttles, J. T.; Green, R. N.; Minnis, P.; Smith, G. L.; Staylor, W. F.; Wielicki, B. A.; Walker, I. J.; Young, D. F.; Taylor, V. R.; Stowe, L. L.

    1988-01-01

    Presented are shortwave angular radiation models which are required for analysis of satellite measurements of Earth radiation, such as those fro the Earth Radiation Budget Experiment (ERBE). The models consist of both bidirectional and directional parameters. The bidirectional parameters are anisotropic function, standard deviation of mean radiance, and shortwave-longwave radiance correlation coefficient. The directional parameters are mean albedo as a function of Sun zenith angle and mean albedo normalized to overhead Sun. Derivation of these models from the Nimbus 7 ERB (Earth Radiation Budget) and Geostationary Operational Environmental Satellite (GOES) data sets is described. Tabulated values and computer-generated plots are included for the bidirectional and directional modes.

  16. Angular radiation models for earth-atmosphere system. Volume 2: Longwave radiation

    NASA Technical Reports Server (NTRS)

    Suttles, J. T.; Green, R. N.; Smith, G. L.; Wielicki, B. A.; Walker, I. J.; Taylor, V. R.; Stowe, L. L.

    1989-01-01

    The longwave angular radiation models that are required for analysis of satellite measurements of Earth radiation, such as those from the Earth Radiation Budget Experiment (ERBE) are presented. The models contain limb-darkening characteristics and mean fluxes. Limb-darkening characteristics are the longwave anisotropic factor and the standard deviation of the longwave radiance. Derivation of these models from the Nimbus 7 ERB (Earth Radiation Budget) data set is described. Tabulated values and computer-generated plots are included for the limb-darkening and mean-flux models.

  17. Radiation Effects Investigations Based on Atmospheric Radiation Model (ATMORAD) Considering GEANT4 Simulations of Extensive Air Showers and Solar Modulation Potential.

    PubMed

    Hubert, Guillaume; Cheminet, Adrien

    2015-07-01

    The natural radiative atmospheric environment is composed of secondary cosmic rays produced when primary cosmic rays hit the atmosphere. Understanding atmospheric radiations and their dynamics is essential for evaluating single event effects, so that radiation risks in aviation and the space environment (space weather) can be assessed. In this article, we present an atmospheric radiation model, named ATMORAD (Atmospheric Radiation), which is based on GEANT4 simulations of extensive air showers according to primary spectra that depend only on the solar modulation potential (force-field approximation). Based on neutron spectrometry, solar modulation potential can be deduced using neutron spectrometer measurements and ATMORAD. Some comparisons between our methodology and standard approaches or measurements are also discussed. This work demonstrates the potential for using simulations of extensive air showers and neutron spectroscopy to monitor solar activity.

  18. Atmospheric radiation measurement unmanned aerospace vehicle (ARM-UAV) program

    SciTech Connect

    Bolton, W.R.

    1996-11-01

    ARM-UAV is part of the multi-agency U.S. Global Change Research Program and is addressing the largest source of uncertainty in predicting climatic response: the interaction of clouds and the sun`s energy in the Earth`s atmosphere. An important aspect of the program is the use of unmanned aerospace vehicles (UAVs) as the primary airborne platform. The ARM-UAV Program has completed two major flight series: The first series conducted in April, 1994, using an existing UAV (the General Atomics Gnat 750) consisted of eight highly successful flights at the DOE climate site in Oklahoma. The second series conducted in September/October, 1995, using two piloted aircraft (Egrett and Twin Otter), featured simultaneous measurements above and below clouds and in clear sky. Additional flight series are planned to continue study of the cloudy and clear sky energy budget in the Spring and Fall of 1996 over the DOE climate site in Oklahoma. 3 refs., 4 figs., 1 tab.

  19. How does the radiation therapist affect the cancer patients' experience of the radiation treatment?

    PubMed

    Egestad, H

    2013-09-01

    Previous studies of head and neck cancer patients going through radiation treatment have shown the treatment causes great physical as well as psychosocial problems. Although previous research acknowledges the needs of cancer patients, there is a lack of literature regarding the patient's perspective about radiation therapy. Studies have rarely focused on the whole experience of radiation treatment. The aim of this study was to illuminate how head and neck cancer patients' encounters with radiation therapists influence patients' experiences going through radiation therapy. The study was conducted via qualitative interviews, using a phenomenological hermeneutic approach. Eleven cancer patients were treated with radiation therapy. This study showed that encounters with radiation therapists have a significant influence on patients' experiences. Cancer patients' contact with radiation therapists can lead to increases or decreases in existential anxiety. When patients experience that the radiation therapist is professionally competent, the existential anxiety decreases. When the radiation therapist make time to build relationships and take responsibility for treatment and side effects, this creates a feeling of security and the treatment is easier to review. The study may indicate that the patients' existential anxiety increases when the radiation therapist shows professional incompetence. PMID:23731059

  20. Advances in Atmospheric Radiation Measurements and Modeling Needed to Improve Air Safety

    NASA Astrophysics Data System (ADS)

    Tobiska, W. Kent; Atwell, William; Beck, Peter; Benton, Eric; Copeland, Kyle; Dyer, Clive; Gersey, Brad; Getley, Ian; Hands, Alex; Holland, Michael; Hong, Sunhak; Hwang, Junga; Jones, Bryn; Malone, Kathleen; Meier, Matthias M.; Mertens, Chris; Phillips, Tony; Ryden, Keith; Schwadron, Nathan; Wender, Stephen A.; Wilkins, Richard; Xapsos, Michael A.

    2015-04-01

    Air safety is tied to the phenomenon of ionizing radiation from space weather, primarily from galactic cosmic rays but also from solar energetic particles. A global framework for addressing radiation issues in this environment has been constructed, but more must be done at international and national levels. Health consequences from atmospheric radiation exposure are likely to exist. In addition, severe solar radiation events may cause economic consequences in the international aviation community due to exposure limits being reached by some crew members. Impacts from a radiation environment upon avionics from high-energy particles and low-energy, thermalized neutrons are now recognized as an area of active interest. A broad community recognizes that there are a number of mitigation paths that can be taken relative to the human tissue and avionics exposure risks. These include developing active monitoring and measurement programs as well as improving scientific modeling capabilities that can eventually be turned into operations. A number of roadblocks to risk mitigation still exist, such as effective pilot training programs as well as monitoring, measuring, and regulatory measures. An active international effort toward observing the weather of atmospheric radiation must occur to make progress in mitigating radiation exposure risks. Stakeholders in this process include standard-making bodies, scientific organizations, regulatory organizations, air traffic management systems, aircraft owners and operators, pilots and crew, and even the public.

  1. Bayesian Atmospheric Radiative Transfer (BART) Code and Application to WASP-43b

    NASA Astrophysics Data System (ADS)

    Blecic, Jasmina; Harrington, Joseph; Cubillos, Patricio; Bowman, Oliver; Rojo, Patricio; Stemm, Madison; Lust, Nathaniel B.; Challener, Ryan; Foster, Austin James; Foster, Andrew S.; Blumenthal, Sarah D.; Bruce, Dylan

    2016-01-01

    We present a new open-source Bayesian radiative-transfer framework, Bayesian Atmospheric Radiative Transfer (BART, https://github.com/exosports/BART), and its application to WASP-43b. BART initializes a model for the atmospheric retrieval calculation, generates thousands of theoretical model spectra using parametrized pressure and temperature profiles and line-by-line radiative-transfer calculation, and employs a statistical package to compare the models with the observations. It consists of three self-sufficient modules available to the community under the reproducible-research license, the Thermochemical Equilibrium Abundances module (TEA, https://github.com/dzesmin/TEA, Blecic et al. 2015}, the radiative-transfer module (Transit, https://github.com/exosports/transit), and the Multi-core Markov-chain Monte Carlo statistical module (MCcubed, https://github.com/pcubillos/MCcubed, Cubillos et al. 2015). We applied BART on all available WASP-43b secondary eclipse data from the space- and ground-based observations constraining the temperature-pressure profile and molecular abundances of the dayside atmosphere of WASP-43b. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

  2. Infrared characteristic radiation of water condensation and freezing in connection with atmospheric phenomena

    NASA Astrophysics Data System (ADS)

    Tatartchenko, Vitali A.

    2010-07-01

    This paper considers the emission of infrared characteristic radiation during the first order phase transitions of water (condensation and crystallization). Experimental results are analyzed in terms of their correspondence to the theoretical models. These models are based on the assumption that the particle's (atom, molecule, or cluster) transition from the higher energetic level (vapor or liquid) to a lower one (liquid or crystal) produces an emission of one or more photons. The energy of these photons depends on the latent energy of the phase transition and the character of bonds formed by the particle in the new phase. Based on experimental data, the author proposes a model explaining the appearance of a window of transparency for the characteristic radiation in the substances when first order phase transitions take place. The effect under investigation must play a very important role in atmospheric phenomena: it is one of the sources of Earth's cooling; formation of hailstorm clouds in the atmosphere is accompanied by intensive characteristic infrared radiation that could be detected for process characterization and meteorological warnings. The effect can be used for atmospheric heat accumulation. Together with the energy of wind, falling water, and solar energy, fog and cloud formation could give us a forth source of ecologically pure energy. Searching for the presence of water in the atmospheres of other planets might also be possible using this technique. Furthermore, this radiation might explain the red color and infrared emission of Jupiter.

  3. Proceedings of the third Atmospheric Radiation Measurement (ARM) science team meeting

    SciTech Connect

    Not Available

    1994-03-01

    This document contains the summaries of papers presented at the 1993 Atmospheric Radiation Measurement (ARM) Science Team meeting held in Morman, Oklahoma. To put these papers in context, it is useful to consider the history and status of the ARM Program at the time of the meeting. Individual papers have been cataloged separately.

  4. Atmospheric Radiation Measurement Climate Research Facility (ACRF Instrumentation Status: New, Current, and Future)

    SciTech Connect

    JW Voyles

    2008-01-30

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  5. Experimental study of the interaction of THz radiation FEL with the atmosphere and water droplet aerosol

    NASA Astrophysics Data System (ADS)

    Matvienko, G. G.; Lisenko, A. A.; Babchenko, S. V.; Kargin, B. A.; Kablukova, E. G.; Kubarev, V. V.

    2015-11-01

    The interaction of radiation of the Novosibirsk Free Electron Laser (FEL) at a wavelength of 130 μm in the atmospheric transmission window with a model aerosol cloud having the known droplet size distribution function has been studied experimentally. The experimental findings are compared with theoretical calculations obtained from solution of the lidar equation for the conditions of the experiment.

  6. Fundamental remote sensing science research program. Part 1: Scene radiation and atmospheric effects characterization project

    NASA Technical Reports Server (NTRS)

    Murphy, R. E.; Deering, D. W.

    1984-01-01

    Brief articles summarizing the status of research in the scene radiation and atmospheric effect characterization (SRAEC) project are presented. Research conducted within the SRAEC program is focused on the development of empirical characterizations and mathematical process models which relate the electromagnetic energy reflected or emitted from a scene to the biophysical parameters of interest.

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

    PubMed

    Yagoda, H

    1964-01-01

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

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

    PubMed

    Yagoda, H

    1964-01-01

    Assuming a constant interplanetary flux of galactic cosmic radiation and a model planetary atmosphere, it is possible to evaluate the magnitude of secondary ionization phenomena therein from parameters measured on Earth. The Martian atmosphere is of particular interest as its total air mass, estimated between 354 and 109 g cm-2, is in the vicinity of the Pfotzer cosmic ray maximum. Assuming the absence of a magnetic field on Mars the maximum neutron production would occur at an atmospheric depth of 75 +/- 5 g cm-2. With the lower air mass limit the surface flux of neutrons reaching the Martian surface could be about 240 times greater than observed at Earth's sea level. Surface minerals containing nuclei with large capture cross sections for slow neutrons, such as Li6, B10 and U235, could thus serve as valuable indicators for the age of the Martian crust. In general, the tenuous Martian atmosphere would result in greater surface radiation dose rates, particularly during times of relativistic solar flares. If the surface air mass is as low as 109 g cm-2 then the rate of nuclear disintegrations due to galactic cosmic radiation would exceed that on Earth's sea level approximately 1000-fold. The tenuous Martian atmosphere would not be a complete shield for heavy primary nuclei and about 1 percent of the incident flux could reach the surface. PMID:11881641

  9. Investigation of Radiation Affected High Temperature Superconductors - YBCO

    NASA Astrophysics Data System (ADS)

    Veterníková, J.; Chudý, M.; Slugeň, V.; Sojak, S.; Degmová, J.; Snopek, J.

    In this paper, high temperature superconductors are studied in terms of radiation stability, which is necessary for application in fusion reactors. Perspective superconducting materials based on YBCO (Perkovskite structure) were measured by positron annihilation lifetime spectroscopy. Measurements were performed for samples prior to and after fast neutron irradiation in TRIGA MARK II reactor in Vienna. The samples demonstrated accumulation of Cu-O di-vacancies due to the irradiation. Nevertheless, the structure showed regeneration during thermal treatment by defects recombination. Positron spectroscopy results were complemented with values of critical temperature, which also showed changes of superconducting properties after the irradiation and the annealing.

  10. Atmospheric Radiation Measurement Program facilities newsletter, July 1999.

    SciTech Connect

    Sisterson, D. L.

    1999-07-30

    Summer research efforts continue in July with the SGP99 Hydrology Campaign headed by the US Department of Agriculture, Agricultural Research Service. Other participants are the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration, and the ARM Program. This campaign focuses on measuring soil moisture by using satellite-based instruments and takes place July 7--22, 1999. Soil moisture is an important component of Earth's hydrologic cycle and climate, but the understanding of it and the ability to measure it accurately are limited. Scientists need to understand soil moisture better so that it can be incorporated correctly into general circulation models. As an important factor in growing crops, soil moisture dictates a farmer's success or failure. Too much soil moisture can drown out croplands and cause flooding, whereas too little can lead to drought conditions, robbing crops of their life-supporting water. Decisions about which crops to plant and other land use issues depend on the understanding of soil moisture patterns. Soil moisture can be measured in various ways. ARM employs several direct methods using soil moisture probes buried from 1 inch to 6.5 feet below the surface. One type of probe has two stainless steel screens separated by a piece of fiberglass. Electrical resistance, which is a function of soil moisture content, is measured between the screens. Another type of probe measures soil temperature and the increase in temperature after the soil is heated by small heating element. From this measurement, the volume of water in the soil can be calculated.

  11. Modelled Black Carbon Radiative Forcing and Atmospheric Lifetime in AeroCom Phase II Constrained by Aircraft Observations

    SciTech Connect

    Samset, B. H.; Myhre, G.; Herber, Andreas; Kondo, Yutaka; Li, Shao-Meng; Moteki, N.; Koike, Makoto; Oshima, N.; Schwarz, Joshua P.; Balkanski, Y.; Bauer, S.; Bellouin, N.; Berntsen, T.; Bian, Huisheng; Chin, M.; Diehl, Thomas; Easter, Richard C.; Ghan, Steven J.; Iversen, T.; Kirkevag, A.; Lamarque, Jean-Francois; Lin, Guang; Liu, Xiaohong; Penner, Joyce E.; Schulz, M.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, Kostas; Zhang, Kai

    2014-11-27

    Black carbon (BC) aerosols absorb solar radiation, and are generally held to exacerbate global warming through exerting a positive radiative forcing1. However, the total contribution of BC to the ongoing changes in global climate is presently under debate2-8. Both anthropogenic BC emissions and the resulting spatial and temporal distribution of BC concentration are highly uncertain2,9. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood, leading to large estimated uncertainty in BC concentration at high altitudes and far from emission sources10. These uncertainties limit our ability to quantify both the historical, present and future anthropogenic climate impact of BC. Here we compare vertical profiles of BC concentration from four recent aircraft measurement campaigns with 13 state of the art aerosol models, and show that recent assessments may have overestimated present day BC radiative forcing. Further, an atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in transport dominated remote regions. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in the multi-model median direct BC forcing from fossil fuel and biofuel burning over the industrial era.

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

    PubMed

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

    1998-01-01

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

  13. Spectral Invariant Approximation within Atmospheric Radiative Transfer; Applications to EarthCare

    NASA Technical Reports Server (NTRS)

    Marshak, Alexander

    2012-01-01

    Certain algebraic combinations of single-scattering albedo and solar radiation reflected from, or transmitted through, vegetation canopies do not vary with wavelength. These "spectrally-invariant relationships" are the consequence of wavelength independence of the extinction coefficient and scattering phase function in vegetation. In general, this wavelength-independence does not hold in the atmosphere, but in cloud-dominated atmospheres the total extinction and total scattering phase function vary only weakly with wavelength. We identify the conditions under which the spectrally-invariant approximation can accurately describe the extinction and scattering properties of cloudy atmospheres. Validity of the assumptions and accuracy of the approximation is tested with radiative transfer calculations. We discuss the physics behind this phenomenon and possible applications to remote sensing, climate, and the EarthCare, mission in particular.

  14. The effect of atmospheric radiative heating by clouds on the Madden-Julian Oscillation

    NASA Astrophysics Data System (ADS)

    Crueger, Traute; Stevens, Bjorn

    2015-06-01

    This article explores how atmospheric radiative heating, due to the presence of clouds, influences the Madden-Julian Oscillation (MJO) as simulated by four comprehensive atmosphere general circulation models. Simulations in which clouds are transparent to electromagnetic radiation ("clouds-off") are compared with control simulations in which clouds are allowed to interact with radiation ("clouds-on"). Making clouds transparent to radiation leads to robust changes of the mean state: the westerly winds in the equatorial Indo-Pacific area weaken and the precipitation reveals a shift from single to double Intertropical Convergence Zones. These changes are accompanied by weaker MJOs. Also, the moisture sensitivity of precipitation changes, however not consistently within our group of models. Further analyses show that within the active phase of intraseasonal variability, cloud-radiative effects amplify the heating profiles compared to clouds-off. Heating from nonradiative processes is dominated by the parameterized convection, but large-scale heating associated with cloud microphysical processes acting on the grid-scale modifies the shape of the heating profile, leading to a top-heaviness when cloud-radiative effects are accounted for. The radiative heating due to clouds slows down the phase speed of the MJO. Averaged over the entire MJO life cycle, the column-integrated radiative heating due to clouds lags the vertically integrated moist static energy by 40°-60° of longitude (equivalently 7-10 days assuming a period of 60 days). All four models studied reveal more pronounced Kelvin waves when clouds are transparent to radiation, suggesting that cloud-radiative effects on large-scale heating profiles damp smaller scale, or faster, Kelvin waves and amplify MJO-like disturbances.

  15. Atmospheric Radiation Measurement Program facilities newsletter, October 2000.

    SciTech Connect

    Sisterson, D. L.

    2000-11-09

    Energy Balance Bowen Ratio System--Estimates of surface energy fluxes are a primary product of the data collection systems at the ARM SGP CART site. Surface fluxes tell researchers a great deal about the effects of interactions between the sun's energy and Earth. Surface fluxes of latent and sensible heat can be estimated by measuring temperature and relative humidity gradients across a vertical distance. Sensible heat is what we feel coming from a warm sidewalk or a metal car door; it can be measured with a thermometer. Latent heat, on the other hand, is released or absorbed during transformations such as the freezing of water into ice or the evaporation of morning dew from a lawn. Such a transformation is referred to as a ''phase change,'' the conversion of a substance among its solid, liquid, and vapor phases. Phase change is an important aspect of our climate. Earth's water cycle abounds with phase changes: rain falls and evaporates, changing from liquid to vapor; the water vapor in the air condenses to form clouds, changing from a gas into a liquid cloud droplet, and eventually falls to Earth's surface as rain or snow; snow falls and melts to liquid or sublimes directly to water vapor. This cyclic process has no end. Surface vegetation and land use play extremely important roles in surface energy fluxes. Plants absorb and reflect solar radiation and also take up water and expel water vapor. The type of plant material, its stage of growth, and its color determine whether and to what extent the surface and air can couple and exchange energy.

  16. Atmospheric Radiation Measurement Program facilities newsletter, October 2002.

    SciTech Connect

    Holdridge, D. J.

    2002-11-04

    Aerosol Observing System Upgraded--The Aerosol Observing System (AOS) at the SGP central facility recently received maintenance and was upgraded to improve its performance. The AOS measures the properties of the aerosol particles around it. Several AOS components were removed, repaired, and calibrated to operate within specifications. The system continuously gathers information about the way minute aerosol particles interact with solar radiation. A better understanding of these interactions will help climate change researchers integrate aerosol effects more accurately into global climate computer models. Polar Bears Make Work Dangerous at ARM North Slope of Alaska Site--The late development of seasonal sea ice has increased polar bear sitings at ARM's Barrow site. The bears were recently seen next to the ARM instrument towers at Barrow, making the normal work day a bit more tricky for the technicians who are at the site year-round. Polar bears are not afraid of people and will attack and kill. The bears usually spend most of their time on off-shore ice floes hunting seals. This season, a large storm pushed the floes out to sea while the bears were ashore at Barrow, leaving them to forage for food on land until the sea ice reforms with the onset of colder weather. The hungry bears have made working at the Barrow CART site a dangerous proposition. ARM workers carry shotguns with them at all times for protection. On a recent journey to the site, ARM instrument mentor Michael Ritsche encountered the animals. ''You become much more aware of your surroundings,'' said Ritsche after returning safely to Argonne. Barrow residents protect themselves by shooting warning shells to scare the bears away from developed areas. Hearing the firing in the early mornings and late evenings at Barrow reminded Ritsche that he was in a more dangerous world.

  17. 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.

  18. Radiative transfer in the dynamic atmospheres of long period variable stars

    NASA Technical Reports Server (NTRS)

    Luttermoser, Donald G.; Bowen, George H.

    1990-01-01

    An iterative procedure is presented for determining the thermal structure and dynamics of Mira-type stellar atmospheres, where the non-LTE radiative transfer code PANDORA is used in conjunction with the Bowen hydrodynamics code of Iowa State University. Preliminary results are reported for an atmospheric model of a pulsating AGB star of 1 solar mass, 240 solar radii, Teff = 3000 K, and a period of 320 days. At the present time, H, H(-), Mg I, and Mg II radiative transfer calculations have been completed and synthetic spectra are shown for H-alpha. The radiative transfer calculations demonstrate that cooling in the innermost shock of the original Bowen model is underestimated due to the omission of various hydrogen transitions. These initial results suggest that the main shock of the Bowen models are too hot and/or too deep.

  19. Polarization radiation in the planetary atmosphere delimited by a heterogeneous diffusely reflecting surface

    NASA Technical Reports Server (NTRS)

    Strelkov, S. A.; Sushkevich, T. A.

    1983-01-01

    Spatial frequency characteristics (SFC) and the scattering functions were studied in the two cases of a uniform horizontal layer with absolutely black bottom, and an isolated layer. The mathematical model for these examples describes the horizontal heterogeneities in a light field with regard to radiation polarization in a three dimensional planar atmosphere, delimited by a heterogeneous surface with diffuse reflection. The perturbation method was used to obtain vector transfer equations which correspond to the linear and nonlinear systems of polarization radiation transfer. The boundary value tasks for the vector transfer equation that is a parametric set and one dimensional are satisfied by the SFC of the nonlinear system, and are expressed through the SFC of linear approximation. As a consequence of the developed theory, formulas were obtained for analytical calculation of albedo in solving the task of dissemination of polarization radiation in the planetary atmosphere with uniform Lambert bottom.

  20. Earth radiation pressure and the determination of density from atmospheric drag.

    NASA Technical Reports Server (NTRS)

    Slowey, J. W.

    1973-01-01

    The effect of earth radiation pressure relative to that of atmospheric drag increases with height through the lower thermosphere. While it can be entirely neglected as a correction in the determination of density at lower heights, it becomes significant somewhat below 1000 km and rapidly becomes comparable in magnitude to drag above 1000 km. The effects of earth radiation pressure on the orbit of the balloon satellite 1963 30D were calculated during two series of intervals when the orbit was entirely in sunlight. The first of these was when the perigee was very high so that hydrogen was expected to be the dominant atmospheric constituent. The second was when the perigee was lower and helium was expected to be the dominant constituent. Two sets of calculations were performed, one using a constant mean model and the other using a seasonal-latitudinal model, based on reported Tiros VII data, for the albedo and infrared radiation.

  1. Atmospheric Radiation Measurement Program facilities newsletter, November 2000.

    SciTech Connect

    Sisterson, D. L.

    2000-12-01

    Winter Weather Outlook--With the chill of colder temperatures in the air, we can rest assured that the icy grips of winter are just around the corner. The Climate Prediction Center (CPC), a specialized part of the National Weather Service (NWS), has issued its annual winter outlook for the 2000-2001 winter season. The CPC, located in Camp Springs, Maryland, is a government agency that focuses its predictions on Earth's climate. In comparison to the NWS forecasts of short-term weather events, the CPC goes farther into the future (from a week to seasons). The CPC conducts real-time monitoring of Earth's climate and makes predictions of climate variability over land and ocean and in the atmosphere. The CPC also evaluates the sources of major climate anomalies. The operations branch of the CPC prepares long-range forecasts by applying dynamical, empirical, and statistical techniques. The analysis branch performs applied research to identify physical factors responsible for climate fluctuations. The two branches work jointly to test new forecast methods and models, with the goal of improving model output. The CPC also evaluates the outlook for floods, droughts, hurricanes, ozone depletion, and El Nino and La Nina environments. So, what is the CPC outlook for winter 2000-2001? For the most part, winter weather will return to ''normal'' this season, because the El Nino and La Nina anomalies that shaped our past three winters have dissipated. Normal winter weather statistics are based on data for 1961-1990. The strong influence of the sea surface temperature in the tropical Pacific Ocean during an El Nino or La Nina episode, which makes it easier for forecasters to predict the trend for weather events, has given way to more neutral conditions. This winter, we should be prepared for swings in temperature and precipitation. The CPC is forecasting a more normal winter in general. Thus, we should expect colder temperatures than during the past three winters, which were greatly

  2. Do Diurnal Aerosol Changes Affect Daily Average Radiative Forcing?

    SciTech Connect

    Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Berg, Larry K.; Michalsky, Joseph J.; Lantz, K.; Hodges, G. B.

    2013-06-17

    Strong diurnal variability of aerosol has been observed frequently for many urban/industrial regions. How this variability may alter the direct aerosol radiative forcing (DARF), however, is largely unknown. To quantify changes in the time-averaged DARF, we perform an assessment of 29 days of high temporal resolution ground-based data collected during the Two-Column Aerosol Project (TCAP) on Cape Cod, which is downwind of metropolitan areas. We demonstrate that strong diurnal changes of aerosol loading (about 20% on average) have a negligible impact on the 24-h average DARF, when daily averaged optical properties are used to find this quantity. However, when there is a sparse temporal sampling of aerosol properties, which may preclude the calculation of daily averaged optical properties, large errors (up to 100%) in the computed DARF may occur. We describe a simple way of reducing these errors, which suggests the minimal temporal sampling needed to accurately find the forcing.

  3. Atmospheric Radiation Measurement Program facilities newsletter, December 2000.

    SciTech Connect

    Liljegren, J. C.; Holdridge, D. J., ed.

    2001-01-09

    Winter has set its sights upon us, just in time to make the holidays bright. Remembering the joy winter brought us when we were children might help us cope with the hazards and inconvenience of the season, but we can't avoid the coping. The basic mechanisms that support summer storms also occur in winter storms. These mechanisms include low-pressure centers, warm fronts, and cold fronts. As winter approaches, the northern branch of the jet stream dips to the south, bringing cold polar air into the Midwest and Southern Great Plains states. Counterclockwise rotation around a low-pressure center allows relatively warm, moist air from the south to flow northward on the eastern side of the low. Cold air from the north is drawn southward, behind the low-pressure center. Sufficiently cold air and abundant moisture are two ingredients necessary to fuel a winter storm system. The intensity of a storm depends on the strength and position of the jet stream relative to the low-pressure center, as well as horizontal temperature gradients and upper-air disturbances. The most frequent origin for snowstorms that affect the Southern Great Plains states is the lee of the Rocky Mountains. Low-pressure systems develop in this area and move eastward or northeastward, encountering and picking up moisture from the Gulf of Mexico. Such storms contribute to average annual snowfall levels over the ARM Program sites ranging from 5-15 inches in Oklahoma to 15-30 inches in Kansas.

  4. The budget of biologically active ultraviolet radiation in the earth-atmosphere system

    NASA Technical Reports Server (NTRS)

    Frederick, John E.; Lubin, Dan

    1988-01-01

    This study applies the concept of a budget to describe the interaction of solar ultraviolet (UV) radiation with the earth-atmosphere system. The wavelength ranges of interest are the biologically relevant UV-B between 280 and 320 nm and the UV-A from 32000 to 400 nm. The Nimbus 7 solar backscattered ultraviolet (SBUV) instrument provides measurements of total column ozone and information concerning cloud cover which, in combination with a simple model of radiation transfer, define the fractions of incident solar irradiance absorbed in the atmosphere, reflected to space, and absorbed at the ground. Results for the month of July quantify the contribution of fractional cloud cover and cloud optical thickness to the radiation budget's three components. Scattering within a thick cloud layer makes the downward radiation field at the cloud base more isotropic than is the case for clear skies. For small solar zenith angles, typical of summer midday conditions, the effective pathlength of this diffuse irradiance through tropospheric ozone is greater than that under clear-sky conditions. The result is an enhanced absorption of UV-B radiation in the troposphere during cloud-covered conditions. Major changes in global cloud cover or cloud optical thicknesses could alter the ultraviolet radiation received by the biosphere by an amount comparable to that predicted for long-term trends in ozone.

  5. Atmospheric oxygen levels affect mudskipper terrestrial performance: implications for early tetrapods.

    PubMed

    Jew, Corey J; Wegner, Nicholas C; Yanagitsuru, Yuzo; Tresguerres, Martin; Graham, Jeffrey B

    2013-08-01

    The Japanese mudskipper (Periophthalmus modestus), an amphibious fish that possesses many respiratory and locomotive specializations for sojourns onto land, was used as a model to study how changing atmospheric oxygen concentrations during the middle and late Paleozoic Era (400-250 million years ago) may have influenced the emergence and subsequent radiation of the first tetrapods. The effects of different atmospheric oxygen concentrations (hyperoxia = 35%, normoxia = 21%, and hypoxia = 7% O2) on terrestrial performance were tested during exercise on a terrestrial treadmill and during recovery from exhaustive exercise. Endurance and elevated post-exercise oxygen consumption (EPOC; the immediate O2 debt repaid post-exercise) correlated with atmospheric oxygen concentration indicating that when additional oxygen is available P. modestus can increase oxygen utilization both during and following exercise. The time required post-exercise for mudskippers to return to a resting metabolic rate did not differ between treatments. However, in normoxia, oxygen consumption increased above hyperoxic values 13-20 h post-exercise suggesting a delayed repayment of the incurred oxygen debt. Finally, following exercise, ventilatory movements associated with buccopharyngeal aerial respiration returned to their rest-like pattern more quickly at higher concentrations of oxygen. Taken together, the results of this study show that P. modestus can exercise longer and recover quicker under higher oxygen concentrations. Similarities between P. modestus and early tetrapods suggest that increasing atmospheric oxygen levels during the middle and late Paleozoic allowed for elevated aerobic capacity and improved terrestrial performance, and likely led to an accelerated diversification and expansion of vertebrate life into the terrestrial biosphere.

  6. An analytic solution of the radiative transfer equation for a gray scattering atmosphere in motion

    NASA Technical Reports Server (NTRS)

    Pistinner, Shlomi; Shaviv, Giora

    1994-01-01

    We provide a formal analytic solution of the radiative transfer equation for a gray moving atmosphere in a plane parallel geometry. A formal solution in the diffusion and the free-streaming limit is also provided in the case of a spherically extended atmosphere. The formal solutions are written explicitly for scattering atmospheres in which the density and the velocity fields are given by a power law. A self-consistent temperature profile accurate to O(Beta = v/c) is provided for the case in which the absorption or the scattering are temperature independent. The gray extinction temperature profile is considerably simplified in the case of a scattering atmosphere. Steady state flow and homologous expansion are special cases that are considered in detail.

  7. Defining Top-of-Atmosphere Flux Reference Level for Earth Radiation Budget Studies

    NASA Technical Reports Server (NTRS)

    Loeb, N. G.; Kato, S.; Wielicki, B. A.

    2002-01-01

    To estimate the earth's radiation budget at the top of the atmosphere (TOA) from satellite-measured radiances, it is necessary to account for the finite geometry of the earth and recognize that the earth is a solid body surrounded by a translucent atmosphere of finite thickness that attenuates solar radiation differently at different heights. As a result, in order to account for all of the reflected solar and emitted thermal radiation from the planet by direct integration of satellite-measured radiances, the measurement viewing geometry must be defined at a reference level well above the earth s surface (e.g., 100 km). This ensures that all radiation contributions, including radiation escaping the planet along slant paths above the earth s tangent point, are accounted for. By using a field-of- view (FOV) reference level that is too low (such as the surface reference level), TOA fluxes for most scene types are systematically underestimated by 1-2 W/sq m. In addition, since TOA flux represents a flow of radiant energy per unit area, and varies with distance from the earth according to the inverse-square law, a reference level is also needed to define satellite-based TOA fluxes. From theoretical radiative transfer calculations using a model that accounts for spherical geometry, the optimal reference level for defining TOA fluxes in radiation budget studies for the earth is estimated to be approximately 20 km. At this reference level, there is no need to explicitly account for horizontal transmission of solar radiation through the atmosphere in the earth radiation budget calculation. In this context, therefore, the 20-km reference level corresponds to the effective radiative top of atmosphere for the planet. Although the optimal flux reference level depends slightly on scene type due to differences in effective transmission of solar radiation with cloud height, the difference in flux caused by neglecting the scene-type dependence is less than 0.1%. If an inappropriate

  8. The Cloud-Radiative Forcing of North American landfalling Atmospheric Rivers

    NASA Astrophysics Data System (ADS)

    Luo, Q.; Tung, W. W.

    2015-12-01

    Atmospheric Rivers (ARs) are narrow elongated regions with strong horizontal water vapor flux associated with extratropical cyclones. Upon making landfall, conspicuous mid-to-high-latitude stratiform cloud decks with high reflectivity are observed along with the ARs in satellite imagery. The cloud-radiative forcing (CRF) associated with these clouds has only been preliminarily established (e.g., Luo and Tung 2015). Their climatological impacts are not understood, yet the related cloud microphysics and radiation processes are poorly represented in global climate models. We studied the correlations between observed variables including the ECMWF-Interim horizontal water vapor fluxes (IVT) integrated from 1000—300 hPa, CERES-derived cloud water path and CRF, and MODIS cirrus reflectance before, during, and after the ARs impinged on the southwest and northwest coasts of North America (NA) in Nov—March, 2000-2008, with 60 ARs affecting the southwest coast (southwest ARs), and 60 ARs affecting the northwest coast (northwest ARs, Dettinger et al., 2011). Anomalies were calculated by subtracting the average over all time steps. For the southwest ARs, a significant increase of ice clouds took place around the landfalling regions with IVT anomalies >130 kg/m/s on landfalling day-1 and day+0. On day+1, a substantial increase of ice clouds with 50% reduction of IVT anomalies was found along with the ARs. On day+2 to day+3, positive IVT anomalies existed over the central and eastern US. These anomalies could be attributed to the southwest ARs and the secondary ARs that rooted in the Gulf of Mexico and made landfall over central and eastern US. Many parts of the NA continent were covered under ice cloud decks. The IVT anomalies for the northwest ARs were >250 kg/m/s on day-1 to day+0, and approximately 120 kg/m/s on day+1. Nevertheless, the northwest ARs were not observed to make landfall concurrently with the secondary landfalling ARs from the Gulf of Mexico. Only a small

  9. Ultraviolet-radiation-induced methane emissions from meteorites and the Martian atmosphere.

    PubMed

    Keppler, Frank; Vigano, Ivan; McLeod, Andy; Ott, Ulrich; Früchtl, Marion; Röckmann, Thomas

    2012-06-01

    Almost a decade after methane was first reported in the atmosphere of Mars there is an intensive discussion about both the reliability of the observations--particularly the suggested seasonal and latitudinal variations--and the sources of methane on Mars. Given that the lifetime of methane in the Martian atmosphere is limited, a process on or below the planet's surface would need to be continuously producing methane. A biological source would provide support for the potential existence of life on Mars, whereas a chemical origin would imply that there are unexpected geological processes. Methane release from carbonaceous meteorites associated with ablation during atmospheric entry is considered negligible. Here we show that methane is produced in much larger quantities from the Murchison meteorite (a type CM2 carbonaceous chondrite) when exposed to ultraviolet radiation under conditions similar to those expected at the Martian surface. Meteorites containing several per cent of intact organic matter reach the Martian surface at high rates, and our experiments suggest that a significant fraction of the organic matter accessible to ultraviolet radiation is converted to methane. Ultraviolet-radiation-induced methane formation from meteorites could explain a substantial fraction of the most recently estimated atmospheric methane mixing ratios. Stable hydrogen isotope analysis unambiguously confirms that the methane released from Murchison is of extraterrestrial origin. The stable carbon isotope composition, in contrast, is similar to that of terrestrial microbial origin; hence, measurements of this signature in future Mars missions may not enable an unambiguous identification of biogenic methane.

  10. Ultraviolet-radiation-induced methane emissions from meteorites and the Martian atmosphere.

    PubMed

    Keppler, Frank; Vigano, Ivan; McLeod, Andy; Ott, Ulrich; Früchtl, Marion; Röckmann, Thomas

    2012-06-01

    Almost a decade after methane was first reported in the atmosphere of Mars there is an intensive discussion about both the reliability of the observations--particularly the suggested seasonal and latitudinal variations--and the sources of methane on Mars. Given that the lifetime of methane in the Martian atmosphere is limited, a process on or below the planet's surface would need to be continuously producing methane. A biological source would provide support for the potential existence of life on Mars, whereas a chemical origin would imply that there are unexpected geological processes. Methane release from carbonaceous meteorites associated with ablation during atmospheric entry is considered negligible. Here we show that methane is produced in much larger quantities from the Murchison meteorite (a type CM2 carbonaceous chondrite) when exposed to ultraviolet radiation under conditions similar to those expected at the Martian surface. Meteorites containing several per cent of intact organic matter reach the Martian surface at high rates, and our experiments suggest that a significant fraction of the organic matter accessible to ultraviolet radiation is converted to methane. Ultraviolet-radiation-induced methane formation from meteorites could explain a substantial fraction of the most recently estimated atmospheric methane mixing ratios. Stable hydrogen isotope analysis unambiguously confirms that the methane released from Murchison is of extraterrestrial origin. The stable carbon isotope composition, in contrast, is similar to that of terrestrial microbial origin; hence, measurements of this signature in future Mars missions may not enable an unambiguous identification of biogenic methane. PMID:22678286

  11. Measurements and simulations of the radiation exposure to aircraft crew workplaces due to cosmic radiation in the atmosphere.

    PubMed

    Beck, P; Latocha, M; Dorman, L; Pelliccioni, M; Rollet, S

    2007-01-01

    As required by the European Directive 96/29/Euratom, radiation exposure due to natural ionizing radiation has to be taken into account at workplaces if the effective dose could become more than 1 mSv per year. An example of workers concerned by this directive is aircraft crew due to cosmic radiation exposure in the atmosphere. Extensive measurement campaigns on board aircrafts have been carried out to assess ambient dose equivalent. A consortium of European dosimetry institutes within EURADOS WG5 summarized experimental data and results of calculations, together with detailed descriptions of the methods for measurements and calculations. The radiation protection quantity of interest is the effective dose, E (ISO). The comparison of results by measurements and calculations is done in terms of the operational quantity ambient dose equivalent, H(10). This paper gives an overview of the EURADOS Aircraft Crew In-Flight Database and it presents a new empirical model describing fitting functions for this data. Furthermore, it describes numerical simulations performed with the Monte Carlo code FLUKA-2005 using an updated version of the cosmic radiation primary spectra. The ratio between ambient dose equivalent and effective dose at commercial flight altitudes, calculated with FLUKA-2005, is discussed. Finally, it presents the aviation dosimetry model AVIDOS based on FLUKA-2005 simulations for routine dose assessment. The code has been developed by Austrian Research Centers (ARC) for the public usage (http://avidos.healthphysics.at).

  12. Thermal balance of the lower Venus atmosphere: radiative and dynamical effects

    NASA Astrophysics Data System (ADS)

    Afanasenko, T. S.; Rodin, A. V.

    2003-04-01

    The current state and recent evolution of Venus climate is believed to be controlled by greenhouse effect variations in response to modified composition of the atmosphere. The quantitative assessment of the thermal regime of the lower Venus atmosphere is, however, highly complicated due to major uncertaintues in its spectral properties, in particular, spectral line profile, which shape is dependent on temperature, pressure, and specific molecular transition. We present a comprehensive, high-resolution model of the thermal radiation and 1D calculations of the thermal balance, involving both radiative and dynamical heat transfer. Spectroscopic model is based on the war-wing approximation for molecular absorption, and self-consistent micorphysical model of the cloud layer. In the lower atmospheric layers simulated radiative fluxes are concentrated within the windows in between absorption bands and reveal high sensitivity to the far-wing spectral line formfactor. Radiation flux effectively generated at 30-40 km is absorbed at the lower boundary of the cloud deck, with the excess heat being removed by convection and large-scale circulation. Sensitivities of the thermal state and dynamical fluxes to minor constituents and aerosol properties are explored. This work has been supported by RFBR grant #01-02-17481

  13. SPARTA - Solver for Polarized Atmospheric Radiative Transfer Applications: Introduction and application to Saharan dust fields

    NASA Astrophysics Data System (ADS)

    Barlakas, Vasileios; Macke, Andreas; Wendisch, Manfred

    2016-07-01

    Non-spherical particles in the atmosphere absorb and scatter solar radiation. They change the polarization state of solar radiation depending on their shape, size, chemical composition and orientation. To quantify polarization effects, a new three-dimensional (3D) vector radiative transfer model, SPARTA (Solver for Polarized Atmospheric Radiative Transfer Applications) is introduced and validated against benchmark results. SPARTA employs the statistical forward Monte Carlo technique for efficient column-response pixel-based radiance calculations including polarization for 3D inhomogeneous cloudless and cloudy atmospheres. A sensitivity study has been carried out and exemplarily results are presented for two lidar-based mineral dust fields. The scattering and absorption properties of the dust particles have been computed for spheroids and irregular shaped particles. Polarized radiance fields in two-dimensional (2D) and one-dimensional (1D) inhomogeneous Saharan dust fields have been calculated at 532 nm wavelength. The domain-averaged results of the normalized reflected radiance are almost identical for the 1D and 2D modes. In the areas with large spatial gradient in optical thickness with expected significant horizontal photon transport, the radiance fields of the 2D mode differ by about ±12% for the first Stokes component (radiance, I) and ±8% for the second Stokes component (linear polarization, Q) from the fields of the 1D mode.

  14. Global climate modeling of Saturn's atmosphere: fast and accurate radiative transfer and exploration of seasonal variability

    NASA Astrophysics Data System (ADS)

    Guerlet, Sandrine; Spiga, A.; Sylvestre, M.; Fouchet, T.; Millour, E.; Wordsworth, R.; Leconte, J.; Forget, F.

    2013-10-01

    Recent observations of Saturn’s stratospheric thermal structure and composition revealed new phenomena: an equatorial oscillation in temperature, reminiscent of the Earth's Quasi-Biennal Oscillation ; strong meridional contrasts of hydrocarbons ; a warm “beacon” associated with the powerful 2010 storm. Those signatures cannot be reproduced by 1D photochemical and radiative models and suggest that atmospheric dynamics plays a key role. This motivated us to develop a complete 3D General Circulation Model (GCM) for Saturn, based on the LMDz hydrodynamical core, to explore the circulation, seasonal variability, and wave activity in Saturn's atmosphere. In order to closely reproduce Saturn's radiative forcing, a particular emphasis was put in obtaining fast and accurate radiative transfer calculations. Our radiative model uses correlated-k distributions and spectral discretization tailored for Saturn's atmosphere. We include internal heat flux, ring shadowing and aerosols. We will report on the sensitivity of the model to spectral discretization, spectroscopic databases, and aerosol scenarios (varying particle sizes, opacities and vertical structures). We will also discuss the radiative effect of the ring shadowing on Saturn's atmosphere. We will present a comparison of temperature fields obtained with this new radiative equilibrium model to that inferred from Cassini/CIRS observations. In the troposphere, our model reproduces the observed temperature knee caused by heating at the top of the tropospheric aerosol layer. In the lower stratosphere (20mbar radiative heating/cooling by trace

  15. A probabilistic approach to radiative energy loss calculations for optically thick atmospheres - Hydrogen lines and continua

    NASA Technical Reports Server (NTRS)

    Canfield, R. C.; Ricchiazzi, P. J.

    1980-01-01

    An approximate probabilistic radiative transfer equation and the statistical equilibrium equations are simultaneously solved for a model hydrogen atom consisting of three bound levels and ionization continuum. The transfer equation for L-alpha, L-beta, H-alpha, and the Lyman continuum is explicitly solved assuming complete redistribution. The accuracy of this approach is tested by comparing source functions and radiative loss rates to values obtained with a method that solves the exact transfer equation. Two recent model solar-flare chromospheres are used for this test. It is shown that for the test atmospheres the probabilistic method gives values of the radiative loss rate that are characteristically good to a factor of 2. The advantage of this probabilistic approach is that it retains a description of the dominant physical processes of radiative transfer in the complete redistribution case, yet it achieves a major reduction in computational requirements.

  16. Comparison of free radicals formation induced by cold atmospheric plasma, ultrasound, and ionizing radiation.

    PubMed

    Rehman, Mati Ur; Jawaid, Paras; Uchiyama, Hidefumi; Kondo, Takashi

    2016-09-01

    Plasma medicine is increasingly recognized interdisciplinary field combining engineering, physics, biochemistry and life sciences. Plasma is classified into two categories based on the temperature applied, namely "thermal" and "non-thermal" (i.e., cold atmospheric plasma). Non-thermal or cold atmospheric plasma (CAP) is produced by applying high voltage electric field at low pressures and power. The chemical effects of cold atmospheric plasma in aqueous solution are attributed to high voltage discharge and gas flow, which is transported rapidly on the liquid surface. The argon-cold atmospheric plasma (Ar-CAP) induces efficient reactive oxygen species (ROS) in aqueous solutions without thermal decomposition. Their formation has been confirmed by electron paramagnetic resonance (EPR) spin trapping, which is reviewed here. The similarities and differences between the plasma chemistry, sonochemistry, and radiation chemistry are explained. Further, the evidence for free radical formation in the liquid phase and their role in the biological effects induced by cold atmospheric plasma, ultrasound and ionizing radiation are discussed.

  17. An Open-Source Bayesian Atmospheric Radiative Transfer (BART) Code, and Application to WASP-12b

    NASA Astrophysics Data System (ADS)

    Harrington, Joseph; Blecic, Jasmina; Cubillos, Patricio; Rojo, Patricio M.; Loredo, Thomas J.; Bowman, Matthew O.; Foster, Andrew S.; Stemm, Madison M.; Lust, Nate B.

    2014-11-01

    Atmospheric retrievals for solar-system planets typically fit, either with a minimizer or by eye, a synthetic spectrum to high-resolution (Δλ/λ ~ 1000-100,000) data with S/N > 100 per point. In contrast, exoplanet data often have S/N ~ 10 per point, and may have just a few points representing bandpasses larger than 1 um. To derive atmospheric constraints and robust parameter uncertainty estimates from such data requires a Bayesian approach. To date there are few investigators with the relevant codes, none of which are publicly available. We are therefore pleased to announce the open-source Bayesian Atmospheric Radiative Transfer (BART) code. BART uses a Bayesian phase-space explorer to drive a radiative-transfer model through the parameter phase space, producing the most robust estimates available for the thermal profile and chemical abundances in the atmosphere. We present an overview of the code and an initial application to Spitzer eclipse data for WASP-12b. We invite the community to use and improve BART via the open-source development site GitHub.com. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

  18. An Open-Source Bayesian Atmospheric Radiative Transfer (BART) Code, with Application to WASP-12b

    NASA Astrophysics Data System (ADS)

    Harrington, Joseph; Blecic, Jasmina; Cubillos, Patricio; Rojo, Patricio; Loredo, Thomas J.; Bowman, M. Oliver; Foster, Andrew S. D.; Stemm, Madison M.; Lust, Nate B.

    2015-01-01

    Atmospheric retrievals for solar-system planets typically fit, either with a minimizer or by eye, a synthetic spectrum to high-resolution (Δλ/λ ~ 1000-100,000) data with S/N > 100 per point. In contrast, exoplanet data often have S/N ~ 10 per point, and may have just a few points representing bandpasses larger than 1 um. To derive atmospheric constraints and robust parameter uncertainty estimates from such data requires a Bayesian approach. To date there are few investigators with the relevant codes, none of which are publicly available. We are therefore pleased to announce the open-source Bayesian Atmospheric Radiative Transfer (BART) code. BART uses a Bayesian phase-space explorer to drive a radiative-transfer model through the parameter phase space, producing the most robust estimates available for the thermal profile and chemical abundances in the atmosphere. We present an overview of the code and an initial application to Spitzer eclipse data for WASP-12b. We invite the community to use and improve BART via the open-source development site GitHub.com. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

  19. Modeling Io's Sublimation-Driven Atmosphere: Gas Dynamics and Radiation Emission

    SciTech Connect

    Walker, Andrew C.; Goldstein, David B.; Varghese, Philip L.; Trafton, Laurence M.; Moore, Chris H.; Stewart, Benedicte; Gratiy, Sergey L.; Levin, Deborah A.

    2008-12-31

    Io's sublimation-driven atmosphere is modeled using the direct simulation Monte Carlo method. These rarefied gas dynamics simulations improve upon earlier models by using a three-dimensional domain encompassing the entire planet computed in parallel. The effects of plasma impact heating, planetary rotation, and inhomogeneous surface frost are investigated. Circumplanetary flow is predicted to develop from the warm subsolar region toward the colder night-side. The non-equilibrium thermal structure of the atmosphere, including vibrational and rotational temperatures, is also presented. Io's rotation leads to an asymmetric surface temperature distribution which is found to strengthen circumplanetary flow near the dusk terminator. Plasma heating is found to significantly inflate the atmosphere on both day- and night-sides. The plasma energy flux also causes high temperatures at high altitudes but permits relatively cooler temperatures at low altitudes near the dense subsolar point due to plasma energy depletion. To validate the atmospheric model, a radiative transfer model was developed utilizing the backward Monte Carlo method. The model allows the calculation of the atmospheric radiation from emitting/absorbing and scattering gas using an arbitrary scattering law and an arbitrary surface reflectivity. The model calculates the spectra in the {nu}{sub 2} vibrational band of SO{sub 2} which are then compared to the observational data.

  20. Comparison of free radicals formation induced by cold atmospheric plasma, ultrasound, and ionizing radiation.

    PubMed

    Rehman, Mati Ur; Jawaid, Paras; Uchiyama, Hidefumi; Kondo, Takashi

    2016-09-01

    Plasma medicine is increasingly recognized interdisciplinary field combining engineering, physics, biochemistry and life sciences. Plasma is classified into two categories based on the temperature applied, namely "thermal" and "non-thermal" (i.e., cold atmospheric plasma). Non-thermal or cold atmospheric plasma (CAP) is produced by applying high voltage electric field at low pressures and power. The chemical effects of cold atmospheric plasma in aqueous solution are attributed to high voltage discharge and gas flow, which is transported rapidly on the liquid surface. The argon-cold atmospheric plasma (Ar-CAP) induces efficient reactive oxygen species (ROS) in aqueous solutions without thermal decomposition. Their formation has been confirmed by electron paramagnetic resonance (EPR) spin trapping, which is reviewed here. The similarities and differences between the plasma chemistry, sonochemistry, and radiation chemistry are explained. Further, the evidence for free radical formation in the liquid phase and their role in the biological effects induced by cold atmospheric plasma, ultrasound and ionizing radiation are discussed. PMID:27085689

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

    NASA Technical Reports Server (NTRS)

    Beebe, R.; Suggs, R.

    1986-01-01

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

  2. Continuous Water Vapor Profiles for the Fixed Atmospheric Radiation Measurement Sites

    SciTech Connect

    Jensen, M.; Troyan, D.

    2006-01-09

    The Atmospheric Radiation Measurement (ARM) Program defined a specific metric for the first quarter of Fiscal Year 2006 to complete a continuous time series of the vertical profile of water vapor for selected 30-day periods from each of the fixed ARM sites. In order to accomplish this metric, a new technique devised to incorporate radiosonde data, microwave radiometer data and analysis information from numerical weather forecast models has been developed. The product of this analysis, referred to as the merged sounding value-added product, includes vertical profiles of atmospheric water vapor concentration and several other important thermodynamic state variables at 1-minute time intervals and 266 vertical levels.

  3. Clear-sky Atmospheric Radiative Transfer: A Model Intercomparison for Shortwave Irradiances

    NASA Astrophysics Data System (ADS)

    Wang, P.; Knap, W. H.; Munneke, P. Kuipers; Stammes, P.

    2009-03-01

    This study consists of an intercomparison of clear-sky shortwave irradiances calculated by the Doubling Adding model of KNMI (DAK) and the Simple Model of the Atmospheric Radiative Transfer of Sunshine (SMARTS). The DAK and SMARTS models are run with identical input (state profiles, water vapour, ozone, aerosols, etc.) and the differences between the models are examined in terms of broadband shortwave irradiances as a function of solar zenith angle. The DAK and SMARTS models agree very well. For a pure Rayleigh atmosphere the differences in the irradiances are less than 5 W/m2. For cases with aerosols the differences of the irradiances are within 10 W/m2.

  4. Methods of editing cloud and atmospheric layer affected pixels from satellite data

    NASA Technical Reports Server (NTRS)

    Nixon, P. R. (Principal Investigator); Wiegand, C. L.; Richardson, A. J.; Johnson, M. P.

    1982-01-01

    Practical methods of computer screening cloud-contaminated pixels from data of various satellite systems are proposed. Examples are given of the location of clouds and representative landscape features in HCMM spectral space of reflectance (VIS) vs emission (IR). Methods of screening out cloud affected HCMM are discussed. The character of subvisible absorbing-emitting atmospheric layers (subvisible cirrus or SCi) in HCMM data is considered and radiosonde soundings are examined in relation to the presence of SCi. The statistical characteristics of multispectral meteorological satellite data in clear and SCi affected areas are discussed. Examples in TIROS-N and NOAA-7 data from several states and Mexico are presented. The VIS-IR cluster screening method for removing clouds is applied to a 262, 144 pixel HCMM scene from south Texas and northeast Mexico. The SCi that remain after cluster screening are sited out by applying a statistically determined IR limit.

  5. Radiation

    NASA Video Gallery

    Outside the protective cocoon of Earth's atmosphere, the universe is full of harmful radiation. Astronauts who live and work in space are exposed not only to ultraviolet rays but also to space radi...

  6. Ultraviolet radiation climatology of the Earth`s surface and lower atmosphere. Final report

    SciTech Connect

    Madronich, S.; Stamnes, K.

    1999-03-01

    Ultraviolet (UV) radiation is the driving force of tropospheric chemistry and is furthermore detrimental to most living tissues. A three year modeling program was carried out to characterize the UV radiation in the lower atmosphere, with the objective of development a climatology of UV biologically active radiation, and of photo-dissociation reaction rates that are key to tropospheric chemistry. A comprehensive model, the Tropospheric Ultraviolet-Visible (TUV) model, was developed and made available to the scientific community. The model incorporates updated spectroscopic data, recent advances in radiative transfer theory, and allows flexible customization for the needs of different users. The TUV model has been used in conjunction with satellite-derived measurements of total atmospheric ozone and cloud amount, to develop a global climatology of UV radiation reaching the surface of the Earth. Initial validation studies are highly encouraging, showing that model predictions agree with direct measurements to ca. 5--10% at times when environmental conditions are well known, and to 10--30% for monthly averages when local environmental conditions can only be estimated remotely from satellite-based measurements. Additional validation studies are continuing.

  7. Model atmospheres and radiation of magnetic neutron stars: Anisotropic thermal emission

    NASA Technical Reports Server (NTRS)

    Pavlov, G. G.; Shibanov, Yu. A.; Ventura, J.; Zavlin, V. E.

    1994-01-01

    We investigate the anisotropy of the thermal radiation emitted by a surface element of a neutron star atmosphere (e.g., by a polar cap of a radio pulsar). Angular dependences of the partial fluxes at various photon energies, and spectra at various angles are obtained for different values of the effective temperature T(sub eff) and magnetic field strength B, and for different directions of the magnetic field. It is shown that the local radiation of the magnetized neutron star atmospheres is highly anisotropic, with the maximum flux emitted in the magnetic field direction. At high B the angular dependences in the soft X-ray range have two maxima, a high narrow peak along B and a lower and broader maximum at intermediate angles. The radiation is strongly polarized, the modulation of the degree of polarization due to the rotation of the neurtron star may be much higher than that for the radiative flux. The results obtained are compared with recent ROSAT observations of the thermal-like radiation from the radio pulsars PSR 1929+10 and PSR J0437-4715.

  8. Improvement and Application of Atmospheric Radiative Transfer Models for Prediction of the Climatic Effects of Aerosol

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Mlawer, Eli J.; Sokolik, Irina N.; Clough, Shepard A.; Toon, Owen B.

    1998-01-01

    This paper presents a radiative transfer model that has been developed to accurately predict the atmospheric radiant flux in both the infrared and the solar spectrum with a minimum of computational effort. The model is designed to be included in numerical climate models. To assess the accuracy of the model, the results are compared to other more detailed models for several standard cases in the solar and thermal spectrum. As the thermal spectrum has been treated in other publications, we focus here on the solar part of the spectrum. We perform several example calculations focussing on the question of absorption of solar radiation by gases and aerosols.

  9. Improvement and Application of Atmospheric Radiative Transfer Models for Prediction of the Climatic Effects of Aerosol

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.

    1998-01-01

    This paper presents a radiative transfer model that has been developed to accurately predict the atmospheric radiant flux in both the infrared and the solar spectrum with a minimum of computational effort. The model is designed to be included in numerical climate models. To assess the accuracy of the model, the results are compared to other more detailed models for several standard cases in the solar and thermal spectrum. As the thermal spectrum has been treated in other publications we focus here on the solar part of the spectrum. We perform several example calculations focussing on the question of absorption of solar radiation by gases and aerosols.

  10. Tools for Atmospheric Radiative Transfer: Streamer and FluxNet. Revised

    NASA Technical Reports Server (NTRS)

    Key, Jeffrey R.; Schweiger, Axel J.

    1998-01-01

    Two tools for the solution of radiative transfer problems are presented. Streamer is a highly flexible medium spectral resolution radiative transfer model based on the plane-parallel theory of radiative transfer. Capable of computing either fluxes or radiances, it is suitable for studying radiative processes at the surface or within the atmosphere and for the development of remote-sensing algorithms. FluxNet is a fast neural network-based implementation of Streamer for computing surface fluxes. It allows for a sophisticated treatment of radiative processes in the analysis of large data sets and potential integration into geophysical models where computational efficiency is an issue. Documentation and tools for the development of alternative versions of Fluxnet are available. Collectively, Streamer and FluxNet solve a wide variety of problems related to radiative transfer: Streamer provides the detail and sophistication needed to perform basic research on most aspects of complex radiative processes while the efficiency and simplicity of FluxNet make it ideal for operational use.

  11. Radiation Power Affected by Current and Wall Radius in Water Cooled Vortex Wall-stabilized Arc

    NASA Astrophysics Data System (ADS)

    Iwao, Toru; Nakamura, Takaya; Yanagi, Kentaro; Yamamoto, Shinji

    2015-11-01

    The arc lighting to obtain the environment to evacuate, save the life, keep the safety and be comfortable are focus on. The lack of radiation intensity and color rendering is problem because of inappropriate energy balance. Some researchers have researched the arc lamp mixed with metal vapor for improvement of color rendering spectrum. The metal vapor can emit the high intense radiation. In addition, the radiation is derived from the high temperature medium. Because the arc temperature can be controlled by current and arc radius, the radiation can be controlled by the current and arc radius. This research elucidates the radiation power affected by the current and wall radius in wall-stabilized arc of water-cooled vortex type. As a result, the radiation power increases with increasing the square of current / square of wall radius because of the temperature distribution which is derived from the current density at the simulation.

  12. Radiative energy balance of Venus based on improved models of the middle and lower atmosphere

    NASA Astrophysics Data System (ADS)

    Haus, R.; Kappel, D.; Tellmann, S.; Arnold, G.; Piccioni, G.; Drossart, P.; Häusler, B.

    2016-07-01

    The distribution of sources and sinks of radiative energy forces the atmospheric dynamics. The radiative transfer simulation model described by Haus et al. (2015b) is applied to calculate fluxes and temperature change rates in the middle and lower atmosphere of Venus (0-100 km) covering the energetic significant spectral range 0.125-1000 μm. The calculations rely on improved models of atmospheric parameters (temperature profiles, cloud parameters, trace gas abundances) retrieved from Venus Express (VEX) data (mainly VIRTIS-M-IR, but also VeRa and SPICAV/SOIR with respect to temperature results). The earlier observed pronounced sensitivity of the radiative energy balance of Venus to atmospheric parameter variations is confirmed, but present detailed comparative analyses of possible influence quantities ensure unprecedented insights into radiative forcing on Venus by contrast with former studies. Thermal radiation induced atmospheric cooling rates strongly depend on temperature structure and cloud composition, while heating rates are mainly sensitive to insolation conditions and UV absorber distribution. Cooling and heating rate responses to trace gas variations and cloud mode 1 abundance changes are small, but observed variations of cloud mode 2 abundances and altitude profiles reduce cooling at altitudes 65-80 km poleward of 50°S by up to 30% compared to the neglect of cloud parameter changes. Cooling rate variations with local time below 80 km are in the same order of magnitude. Radiative effects of the unknown UV absorber are modeled considering a proxy that is based on a suitable parameterization of optical properties, not on a specific chemical composition, and that is independent of the used cloud model. The UV absorber doubles equatorial heating near 68 km. Global average radiative equilibrium at the top of atmosphere (TOA) is characterized by the net flux balance of 156 W/m2, the Bond albedo of 0.76, and the effective planetary emission temperature of 228

  13. Fundamental remote sensing science research program: The Scene Radiation and Atmospheric Effects Characterization Project

    NASA Technical Reports Server (NTRS)

    Deering, D. W.

    1985-01-01

    The Scene Radiation and Atmospheric Effects Characterization (SRAEC) Project was established within the NASA Fundamental Remote Sensing Science Research Program to improve our understanding of the fundamental relationships of energy interactions between the sensor and the surface target, including the effect of the atmosphere. The current studies are generalized into the following five subject areas: optical scene modeling, Earth-space radiative transfer, electromagnetic properties of surface materials, microwave scene modeling, and scatterometry studies. This report has been prepared to provide a brief overview of the SRAEC Project history and objectives and to report on the scientific findings and project accomplishments made by the nineteen principal investigators since the project's initiation just over three years ago. This annual summary report derives from the most recent annual principal investigators meeting held January 29 to 31, 1985.

  14. Infrared radiative transfer in atmospheres of Earth-like planets around F, G, K, and M stars. II. Thermal emission spectra influenced by clouds

    NASA Astrophysics Data System (ADS)

    Vasquez, M.; Schreier, F.; Gimeno García, S.; Kitzmann, D.; Patzer, B.; Rauer, H.; Trautmann, T.

    2013-09-01

    Context. Clouds play an important role in the radiative transfer of planetary atmospheres because of the influence they have on the different molecular signatures through scattering and absorption processes. Furthermore, they are important modulators of the radiative energy budget affecting surface and atmospheric temperatures. Aims: We present a detailed study of the thermal emission of cloud-covered planets orbiting F-, G-, K-, and M-type stars. These Earth-like planets include planets with the same gravity and total irradiation as Earth, but can differ significantly in the upper atmosphere. The impact of single-layered clouds is analyzed to determine what information on the atmosphere may be lost or gained. The planetary spectra are studied at different instrument resolutions and compared to previously calculated low-resolution spectra. Methods: A line-by-line molecular absorption model coupled with a multiple scattering radiative transfer solver was used to calculate the spectra of cloud-covered planets. The atmospheric profiles used in the radiation calculations were obtained with a radiative-convective climate model combined with a parametric cloud description. Results: In the high-resolution flux spectra, clouds changed the intensities and shapes of the bands of CO2, N2O, H2O, CH4, and O3. Some of these bands turned out to be highly reduced by the presence of clouds, which causes difficulties for their detection. The most affected spectral bands resulted for the planet orbiting the F-type star. Clouds could lead to false negative interpretations for the different molecular species investigated. However, at low resolution, clouds were found to be crucial for detecting some of the molecular bands that could not be distinguished in the cloud-free atmospheres. The CO2 bands were found to be less affected by clouds. Radiation sources were visualized with weighting functions at high resolution. Conclusions: Knowledge of the atmospheric temperature profile is

  15. Analysis of Atmospheric Aerosol Data Sets and Application of Radiative Transfer Models to Compute Aerosol Effects

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Bergstrom, Robert W.; Redemann, Jens

    2002-01-01

    This report is the final report for "Analysis of Atmospheric Aerosol Data Sets and Application of Radiative Transfer Models to Compute Aerosol Effects". It is a bibliographic compilation of 29 peer-reviewed publications (published, in press or submitted) produced under this Cooperative Agreement and 30 first-authored conference presentations. The tasks outlined in the various proposals are listed below with a brief comment as to the research performed. Copies of title/abstract pages of peer-reviewed publications are attached.

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

    NASA Technical Reports Server (NTRS)

    Raschke, E.

    1986-01-01

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

  17. Continuous Profiles of Cloud Microphysical Properties for the Fixed Atmospheric Radiation Measurement Sites

    SciTech Connect

    Jensen, M; Jensen, K

    2006-06-01

    The Atmospheric Radiation Measurement (ARM) Program defined a specific metric for the third quarter of Fiscal Year 2006 to produce and refine a one-year continuous time series of cloud microphysical properties based on cloud radar measurements for each of the fixed ARM sites. To accomplish this metric, we used a combination of recently developed algorithms that interpret radar reflectivity profiles, lidar backscatter profiles, and microwave brightness temperatures into the context of the underlying cloud microphysical structure.

  18. Further considerations of cosmic ray modulation of infra-red radiation in the atmosphere

    NASA Astrophysics Data System (ADS)

    Aplin, K. L.; Lockwood, M.

    2015-08-01

    Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing the traditionally distinct scientific boundaries between astro-particle and atmospheric physics and also requiring understanding of both heliospheric and magnetospheric influences on cosmic rays. Following the paper of Erlykin et al. (2014) we develop further the interpretation of our observed changes in long-wave (LW) radiation, Aplin and Lockwood (2013) by taking account of both cosmic ray ionisation yields and atmospheric radiative transfer. To demonstrate this, we show that the thermal structure of the whole atmosphere needs to be considered along with the vertical profile of ionisation. Allowing for, in particular, ionisation by all components of a cosmic ray shower and not just by the muons, reveals that the effect we have detected is certainly not inconsistent with laboratory observations of the LW absorption cross section. The analysis presented here, although very different from that of Erlykin et al., does come to the same conclusion that the events detected by AL were not caused by individual cosmic ray primaries - not because it is impossible on energetic grounds, but because events of the required energy are too infrequent for the 12 h-1 rate at which they were seen by the AL experiment. The present paper numerically models the effect of three different scenario changes to the primary GCR spectrum which all reproduce the required magnitude of the effect observed by AL. However, they cannot solely explain the observed delay in the peak effect which, if confirmed, would appear to open up a whole new and interesting area in the study of water oligomers and their effects on LW radiation. We argue that a technical artefact in the AL experiment is highly unlikely and that our initial observations merit both a wide-ranging follow-up experiment and more rigorous, self-consistent, three-dimensional radiative transfer modelling.

  19. Radiation-induced late effects in two affected individuals of the Lilo radiation accident.

    PubMed

    Scherthan, Harry; Abend, Michael; Müller, Kerstin; Beinke, Christina; Braselmann, Herbert; Zitzelsberger, Horst; Köhn, Frank M; Pillekamp, Hans; Schiener, Ralf; Das, Oliver; Peter, Ralf U; Herzog, Gerhard; Tzschach, Andreas; Dörr, Harald D; Fliedner, Theodor M; Meineke, Viktor

    2007-05-01

    Radiation exposure leads to a risk for long-term deterministic and stochastic late effects. Two individuals exposed to protracted photon radiation in the radiological accident at the Lilo Military site in Georgia in 1997 received follow-up treatment and resection of several chronic radiation ulcers in the Bundeswehr Hospital Ulm, Germany, in 2003. Multi-parameter analysis revealed that spermatogenetic arrest and serum hormone levels in both patients had recovered compared to the status in 1997. However, we observed a persistence of altered T-cell ratios, increased ICAM1 and beta1-integrin expression, and aberrant bone marrow cells and lymphocytes with significantly increased translocations 6 years after the accident. This investigation thus identified altered end points still detectable years after the accident that suggest persistent genomic damage as well as epigenetic effects in these individuals, which may be associated with an elevated risk for the development of further late effects. Our observations further suggest the development of a chronic radiation syndrome and indicate follow-up parameters in radiation victims.

  20. A treatment of the Zeeman effect using Stokes formalism and its implementation in the Atmospheric Radiative Transfer Simulator (ARTS)

    NASA Astrophysics Data System (ADS)

    Larsson, Richard; Buehler, Stefan A.; Eriksson, Patrick; Mendrok, Jana

    2014-01-01

    This paper presents the practical theory that was used to implement the Zeeman effect using Stokes formalism in the Atmospheric Radiative Transfer Simulator (ARTS). ARTS now treats the Zeeman effect in a general manner for several gas species for all polarizations and takes into account variations in both magnetic and atmospheric fields along a full 3D geometry. We present how Zeeman splitting affects polarization in radiative transfer simulations and find that the effect may be large in Earth settings for polarized receivers in limb observing geometry. We find that not taking a spatially varying magnetic field into account can result in absolute errors in the measurement vector of at least 10 K in Earth magnetic field settings. The paper also presents qualitative tests for O2 lines against previous models (61.15 GHz line) and satellite data from Odin-SMR (487.25 GHz line), and the overall consistency between previous models, satellite data, and the new ARTS Zeeman module seems encouraging.

  1. Infrared Aerosol Radiative Forcing at the Surface and the Top of the Atmosphere

    NASA Technical Reports Server (NTRS)

    Markowicz, Krzysztof M.; Flatau, Piotr J.; Vogelmann, Andrew M.; Quinn, Patricia K.; Welton, Ellsworth J.

    2003-01-01

    We study the clear-sky aerosol radiative forcing at infrared wavelengths using data from the Aerosol Characterization Experiment (ACE-Asia) cruise of the NOAA R/V Ronald H. Brown. Limited number of data points is analyzed mostly from ship and collocated satellite values. An optical model is derived from chemical measurements, lidar profiles, and visible extinction measurements which is used to and estimate the infrared aerosol optical thickness and the single scattering albedo. The IR model results are compared to detailed Fourier Transform Interferometer based infrared aerosol forcing estimates, pyrgeometer based infrared downward fluxes, and against the direct solar forcing observations. This combined approach attests for the self-consistency of the optical model and allows to derive quantities such as the infrared forcing at the top of the atmosphere or the infrared optical thickness. The mean infrared aerosol optical thickness at 10 microns is 0.08 and the single scattering albedo is 0.55. The modeled infrared aerosol forcing reaches 10 W/sq m during the cruise, which is a significant contribution to the total direct aerosol forcing. The surface infrared aerosol radiative forcing is between 10 to 25% of the shortwave aerosol forcing. The infrared aerosol forcing at the top of the atmosphere can go up to 19% of the solar aerosol forcing. We show good agreement between satellite (CERES instrument) retrievals and model results at the top of the atmosphere. Over the Sea of Japan, the average infrared radiative forcing is 4.6 W/sq m in the window region at the surface and it is 1.5 W/sq m at top of the atmosphere. The top of the atmosphere IR forcing efficiency is a strong function of aerosol temperature while the surface IR forcing efficiency varies between 37 and 55 W/sq m (per infrared optical depth unit). and changes between 10 to 18 W/sq m (per infrared optical depth unit).

  2. Exposure to the atmospheric ionizing radiation environment: studies on Icelandic and Italian civilian aviation flight personnel

    NASA Astrophysics Data System (ADS)

    de Angelis, G.; Caldora, M.; Santaquilani, M.; Scipione, R.; Verdecchia, A.; Rafnsson, V.; Hrafnkelsson, J.; Sulem, P.; Gudjonsdottir, A. J.

    The largest source of data on human exposure to low dose rate radiation may be airline flight personnel, if enrolled for studies on health effects induced by the cosmic-ray-generated atmospheric ionizing radiation, whose total dose, increasing over the years, may cause delayed radiation-induced health effects, with the high-LET and highly ionizing neutron component typical of atmospheric radiation. With regards to this, the Italian civilian airline flight personnel have been studied by analyzing the atmospheric ionizing radiation exposure and associated effects. The study population includes all Italian civilian airline flight personnel, both cockpit and cabin crewmembers, whose work history records and actual flights (route, aircraft type, and date for each individual flight for each person where possible) were available. The dose calculations were performed along specific flight legs, taking into account the actual flight profiles for all different routes and the variations with time of solar and geomagnetic parameters, in order to take into account the whole atmospheric neutron spectrum. Dose values for each flight are applied to the flight history of study participants in order to estimate the individual annual and lifetime occupational radiation dose. Following the same protocols for both cohorts in terms of dose evaluation, a comparative study has been performed between the radiation exposure patterns of the Icelandic and the Italian civilian aviation flight personnel. These two populations represent two extremes within the group of worldwide airline personnel. The Icelandic crewmembers, like only in the world their Canadian colleagues, always fly over or very close to the geomagnetic pole, and are this way exposed to high doses within each flight leg, whereas the Italian crewmembers, apart from transatlantic flights, are always flying close to the geomagnetic equator or anyhow quite far from the geomagnetic pole, receiving a small dose rates for each flight

  3. Transport and radiative impacts of atmospheric pollen using online, observation-based emissions

    NASA Astrophysics Data System (ADS)

    Wozniak, M. C.; Steiner, A. L.; Solmon, F.; Li, Y.

    2015-12-01

    Atmospheric pollen emitted from trees and grasses exhibits both a high temporal variability and a highly localized spatial distribution that has been difficult to quantify in the atmosphere. Pollen's radiative impact is also not quantified because it is neglected in climate modeling studies. Here we couple an online, meteorological active pollen emissions model guided by observations of airborne pollen to understand the role of pollen in the atmosphere. We use existing pollen counts from 2003-2008 across the continental U.S. in conjunction with a tree database and historical meteorological data to create an observation-based phenological model that produces accurately scaled and timed emissions. These emissions are emitted and transported within the regional climate model (RegCM4) and the direct radiative effect is calculated. Additionally, we simulate the rupture of coarse pollen grains into finer particles by adding a second size mode for pollen emissions, which contributes to the shortwave radiative forcing and also has an indirect effect on climate.

  4. Analysis of the radiative budget of Venus atmosphere based on infrared Net Exchange Rate formalism

    NASA Astrophysics Data System (ADS)

    Lebonnois, S.; Eymet, V.; Lee, C.; Vatant d'Ollone, J.

    2015-10-01

    The thick cloud cover present in the atmosphere of Venus between roughly 47 and 70 km of altitude plays a crucial role in the radiative balance of this system,by reflecting more than 75 % of the incoming solar flux back to space, absorbing half of the remaining flux, and being also optically thick over most of the infrared spectral range. The temperature profile of the atmosphere of Venus is characterized by a very hot troposphere from the surface (˜735 K) to roughly 60 km altitude, in the middle clouds. The strong greenhouse effect is provided by the 92 bars of CO2 that is the main constituent of the atmosphere and by the thick cloud layer.

  5. Instrument Cross-Comparisons and Automated Quality Control of Atmospheric Radiation Measurement Data

    SciTech Connect

    Moore, S.; Hughes, G.

    2005-03-18

    Within the Atmospheric Radiation Measurement (ARM) instrument network, several different systems often measure the same quantity at the same site. For example, several ARM instruments measure time-series profiles of the atmosphere that were previously available only from balloon-borne radiosonde systems. These instruments include the Radar Wind Profilers (RWP) with Radio-Acoustic Sounding Systems (RASS), the Atmospheric Emitted Radiance Interferometer (AERI), the Microwave Radiometer Profiler (MWRP), and the Raman Lidar (RL). ARM researchers have described methods for direct cross-comparison of time-series profiles (Coulter and Lesht 1996; Turner et al. 1996) and we have extended this concept to the development of methods for automated quality control (QC) of ARM datastreams.

  6. Solar radiation incident on Mars and the outer planets - Latitudinal, seasonal, and atmospheric effects

    NASA Technical Reports Server (NTRS)

    Levine, J. S.; Kraemer, D. R.; Kuhn, W. R.

    1977-01-01

    Calculations of the daily solar radiation incident at the tops of the atmospheres of Mars and the outer planets and its variability with latitude and season are presented in a series of figures and tables. The changes in the latitudinal and seasonal distributions of daily surface insolation during the great Martian dust storm of 1971 (when Martian atmospheric optical depth increased from about tau = 0.1 to 2.0) were significant and dramatically illustrate the effect of atmospheric aerosols on surface insolation; i.e., the mean annual daily insolation at the poles decreased by more than a factor of 100 as tau increased from 0.1 to 2.0.

  7. Comparison of radiative and physiological effects of doubled atmospheric CO{sub 2} on climate

    SciTech Connect

    Sellers, P.J.; Collatz, G.J.; Los, S.O.

    1996-03-08

    The physiological response of terrestrial vegetation when directly exposed to an increase in atmospheric carbon dioxide (CO{sub 2}) concentration could result in warming over the continents in addition to that due to the conventional CO{sub 2} {open_quotes}greenhouse effect.{close_quotes} Results from a coupled biosphere-atmosphere model (SiB2-GCM) indicate that, for doubled CO{sub 2} conditions, evapotranspiration will drop and air temperature will increase over the tropical continents, amplifying the changes resulting from atmospheric radiative effects. The range of responses in surface air temperature and terrestrial carbon uptake due to increased CO{sub 2} are projected to be inversely related in the tropics year-round and inversely related during the growing season elsewhere. 21 refs., 4 figs., 2 tabs.

  8. Direct Measure of Radiative and Dynamical Properties of an Exoplanet Atmosphere

    NASA Astrophysics Data System (ADS)

    de Wit, Julien; Lewis, Nikole K.; Langton, Jonathan; Laughlin, Gregory; Deming, Drake; Batygin, Konstantin; Fortney, Jonathan J.

    2016-04-01

    Two decades after the discovery of 51 Peg b, the formation processes and atmospheres of short-period gas giants remain poorly understood. Observations of eccentric systems provide key insights on those topics as they can illuminate how a planet’s atmosphere responds to changes in incident flux. We report here the analysis of multi-day multi-channel photometry of the eccentric (e∼ 0.93) hot Jupiter HD 80606 b obtained with the Spitzer Space Telescope. The planet’s extreme eccentricity combined with the long coverage and exquisite precision of new periastron-passage observations allow us to break the degeneracy between the radiative and dynamical timescales of HD 80606 b’s atmosphere and constrain its global thermal response. Our analysis reveals that the atmospheric layers probed heat rapidly (∼4 hr radiative timescale) from \\lt 500 to 1400 K as they absorb ∼ 20% of the incoming stellar flux during the periastron passage, while the planet’s rotation period is {93}-35+85 hr, which exceeds the predicted pseudo-synchronous period (40 hr).

  9. Cosmic ray modulation of infra-red radiation in the atmosphere

    NASA Astrophysics Data System (ADS)

    Aplin, Karen; Lockwood, Michael

    2013-04-01

    Cosmic rays produce small charged clusters, known as molecular cluster ions, as they pass through the lower atmosphere. Neutral molecular clusters such as dimers and complexes are expected to make a small contribution to the radiative balance, but atmospheric absorption by charged clusters has not hitherto been observed. Here we describe results from an atmospheric experiment where a thermopile filter radiometer tuned to a 9.15μm absorption band, already associated with infra-red absorption of molecular cluster ions, was used to monitor changes following events identified by a cosmic ray telescope sensitive to high energy (>400MeV) particles, principally muons at the surface. The change in longwave radiation in this absorption band due to molecular cluster ions is 7 mWm-2 for each event recorded by the cosmic ray telescope. The integrated atmospheric energy change for each event is 1.9 Jm-2, whereas the energy density of a typical air shower (40m radius from a 10GeV primary) is estimated to be 10-13 Jm-2, representing a direct amplification factor of 1012. This infra-red absorption from molecular cluster-ions is expected to occur continuously and globally, but calculations suggest that it has only a small effect on climate.

  10. Cosmic ray modulation of infra-red radiation in the atmosphere

    NASA Astrophysics Data System (ADS)

    Aplin, K. L.; Lockwood, M.

    2013-03-01

    Cosmic rays produce molecular cluster ions as they pass through the lower atmosphere. Neutral molecular clusters such as dimers and complexes are expected to make a small contribution to the radiative balance, but atmospheric absorption by charged clusters has not hitherto been observed. In an atmospheric experiment, a narrowband thermopile filter radiometer centred on 9.15 μm, an absorption band previously associated with infra-red absorption of molecular cluster ions, was used to monitor changes following events identified by a cosmic ray telescope sensitive to high-energy (>400 MeV) particles, principally muons. The average change in longwave radiation in this absorption band due to molecular cluster ions is 7 mWm-2. The integrated atmospheric energy density for each event is 2 Jm-2, representing an amplification factor of 1012 compared to the estimated energy density of a typical air shower. This absorption is expected to occur continuously and globally, but calculations suggest that it has only a small effect on climate.

  11. Shortwave radiative heating rate profiles in hazy and clear atmosphere: a sensitivity study

    NASA Astrophysics Data System (ADS)

    Doppler, Lionel; Fischer, Jürgen; Ravetta, François; Pelon, Jacques; Preusker, René

    2010-05-01

    Aerosols have an impact on shortwave heating rate profiles (additional heating or cooling). In this survey, we quantify the impact of several key-parameters on the heating rate profiles of the atmosphere with and without aerosols. These key-parameters are: (1) the atmospheric model (tropical, midlatitude summer or winter, US Standard), (2) the integrated water vapor amount (IWV ), (3) the ground surface (flat and rough ocean, isotropic surface albedo for land), (4) the aerosol composition (dusts, soots or maritimes mixtures with respect to the OPAC-database classification), (5) the aerosol optical depth and (6) vertical postion, and (7) the single-scattering albedo (?o) of the aerosol mixture. This study enables us to evaluate which parameters are most important to take into account in a radiative energy budget of the atmosphere and will be useful for a future study: the retrieval of heating rates profiles from satellite data (CALIPSO, MODIS, MERIS) over the Mediterranean Sea. All the heating rates are computed by using the vector irradiances computed at each pressure level in the spectral interval 0.2 - 3.6μm (shortwave) by the 1D radiative transfer model for atmosphere and ocean: MOMO (Matrix-Operator MOdel) of the Institute for Space Science, FU Berlin 1

  12. Atmospheric Radiation Measurement program climate research facility operations quarterly report July 1 - September 30, 2008.

    SciTech Connect

    Sisterson, D. L.

    2008-10-08

    research accounts are located at the Barrow and Atqasuk sites; the SGP central facility; the TWP Manus, Nauru, and Darwin sites; and the DMF at PNNL. In addition, the ACRF serves as a data repository for a long-term Arctic atmospheric observatory in Eureka, Canada (80 degrees 05 minutes N, 86 degrees 43 minutes W) as part of the multiagency Study of Environmental Arctic Change (SEARCH) Program. NOAA began providing instruments for the site in 2005, and currently cloud radar data are available. The intent of the site is to monitor the important components of the Arctic atmosphere, including clouds, aerosols, atmospheric radiation, and local-scale atmospheric dynamics. Because of the similarity of ACRF NSA data streams and the important synergy that can be formed between a network of Arctic atmospheric observations, much of the SEARCH observatory data are archived in the ARM archive. Instruments will be added to the site over time. For more information, please visit http://www.db.arm.gov/data. The designation for the archived Eureka data is YEU and is now included in the ACRF user metrics. This quarterly report provides the cumulative numbers of visitors and user accounts by site for the period October 1, 2007 - September 30, 2008. Table 2 shows the summary of cumulative users for the period October 1, 2007 - September 30, 2008. For the fourth quarter of FY 2008, the overall number of users is down substantially (about 30%) from last quarter. Most of this decrease resulted from a reduction in the ACRF Infrastructure users (e.g., site visits, research accounts, on-site device accounts, etc.) associated with the AMF China deployment. While users had easy access to the previous AMF deployment in Germany that resulted in all-time high user statistics, physical and remote access to on-site accounts are extremely limited for the AMF deployment in China. Furthermore, AMF data have not yet been released from China to the Data Management Facility for processing, which affects Archive

  13. Atmospheric Radiation Measurement program climate research facility operations quarterly report October 1 - December 31, 2007.

    SciTech Connect

    Sisterson, D. L.

    2008-01-24

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period October 1 - December 31, 2007, for the fixed sites and the mobile site. The AMF has been deployed to Germany and this was the final operational quarter. The first quarter comprises a total of 2,208 hours. Although the average exceeded our goal this quarter, a series of severe weather events (i.e., widespread ice storms) disrupted utility services, which affected the SGP performance measures. Some instruments were covered in ice and power and data communication lines were down for more than 10 days in some areas of Oklahoma and Kansas, which resulted in lost data at the SGP site. The Site Access Request System is a web-based database used to track visitors to the fixed sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. The AMF completed its mission at the end of this quarter in Haselback, Germany (FKB designation). NIM represents the AMF statistics for the Niamey, Niger, Africa, past deployment in 2006. PYE

  14. 3D-radiative transfer in terrestrial atmosphere: An efficient parallel numerical procedure

    NASA Astrophysics Data System (ADS)

    Bass, L. P.; Germogenova, T. A.; Nikolaeva, O. V.; Kokhanovsky, A. A.; Kuznetsov, V. S.

    2003-04-01

    Light propagation and scattering in terrestrial atmosphere is usually studied in the framework of the 1D radiative transfer theory [1]. However, in reality particles (e.g., ice crystals, solid and liquid aerosols, cloud droplets) are randomly distributed in 3D space. In particular, their concentrations vary both in vertical and horizontal directions. Therefore, 3D effects influence modern cloud and aerosol retrieval procedures, which are currently based on the 1D radiative transfer theory. It should be pointed out that the standard radiative transfer equation allows to study these more complex situations as well [2]. In recent year the parallel version of the 2D and 3D RADUGA code has been developed. This version is successfully used in gammas and neutrons transport problems [3]. Applications of this code to radiative transfer in atmosphere problems are contained in [4]. Possibilities of code RADUGA are presented in [5]. The RADUGA code system is an universal solver of radiative transfer problems for complicated models, including 2D and 3D aerosol and cloud fields with arbitrary scattering anisotropy, light absorption, inhomogeneous underlying surface and topography. Both delta type and distributed light sources can be accounted for in the framework of the algorithm developed. The accurate numerical procedure is based on the new discrete ordinate SWDD scheme [6]. The algorithm is specifically designed for parallel supercomputers. The version RADUGA 5.1(P) can run on MBC1000M [7] (768 processors with 10 Gb of hard disc memory for each processor). The peak productivity is equal 1 Tfl. Corresponding scalar version RADUGA 5.1 is working on PC. As a first example of application of the algorithm developed, we have studied the shadowing effects of clouds on neighboring cloudless atmosphere, depending on the cloud optical thickness, surface albedo, and illumination conditions. This is of importance for modern satellite aerosol retrieval algorithms development. [1] Sobolev

  15. Solar Radiation Transport in the Cloudy Atmosphere: A 3D Perspective on Observations and Climate Impacts

    NASA Technical Reports Server (NTRS)

    Davis, Anthony B.; Marshak, Alexander

    2010-01-01

    The interplay of sunlight with clouds is a ubiquitous and often pleasant visual experience, but it conjures up major challenges for weather, climate, environmental science and beyond. Those engaged in the characterization of clouds (and the clear air nearby) by remote sensing methods are even more confronted. The problem comes, on the one hand, from the spatial complexity of real clouds and, on the other hand, from the dominance of multiple scattering in the radiation transport. The former ingredient contrasts sharply with the still popular representation of clouds as homogeneous plane-parallel slabs for the purposes of radiative transfer computations. In typical cloud scenes the opposite asymptotic transport regimes of diffusion and ballistic propagation coexist. We survey the three-dimensional (3D) atmospheric radiative transfer literature over the past 50 years and identify three concurrent and intertwining thrusts: first, how to assess the damage (bias) caused by 3D effects in the operational 1D radiative transfer models? Second, how to mitigate this damage? Finally, can we exploit 3D radiative transfer phenomena to innovate observation methods and technologies? We quickly realize that the smallest scale resolved computationally or observationally may be artificial but is nonetheless a key quantity that separates the 3D radiative transfer solutions into two broad and complementary classes: stochastic and deterministic. Both approaches draw on classic and contemporary statistical, mathematical and computational physics.

  16. Two-dimensional radiative transfer in cloudy atmospheres - The spherical harmonic spatial grid method

    NASA Technical Reports Server (NTRS)

    Evans, K. F.

    1993-01-01

    A new two-dimensional monochromatic method that computes the transfer of solar or thermal radiation through atmospheres with arbitrary optical properties is described. The model discretizes the radiative transfer equation by expanding the angular part of the radiance field in a spherical harmonic series and representing the spatial part with a discrete grid. The resulting sparse coupled system of equations is solved iteratively with the conjugate gradient method. A Monte Carlo model is used for extensive verification of outgoing flux and radiance values from both smooth and highly variable (multifractal) media. The spherical harmonic expansion naturally allows for different levels of approximation, but tests show that the 2D equivalent of the two-stream approximation is poor at approximating variations in the outgoing flux. The model developed here is shown to be highly efficient so that media with tens of thousands of grid points can be computed in minutes. The large improvement in efficiency will permit quick, accurate radiative transfer calculations of realistic cloud fields and improve our understanding of the effect of inhomogeneity on radiative transfer in cloudy atmospheres.

  17. Solar and thermal radiation in the atmosphere of Venus: a proposal for the VIRA update

    NASA Astrophysics Data System (ADS)

    Titov, Dmitrij

    2012-07-01

    The update of the Venus International Reference Atmosphere (VIRA) chapter on solar and thermal radiation is based on the following new data sources that became available in the past two decades passed since the first VIRA model was published in 1985: 1) Venera-15 measurements of the spectra of the outgoing thermal radiation; 2) measurements of the scattered solar radiation within the cloud layer on Vega balloons; 3) ground-based and NIMS/Galileo observations of the Venus night side in the near-infrared spectral range; 4) re-analysis of the earlier measurements of the solar and thermal fluxes onboard Pioneer-Venus and Venera probes; 5) great data set collected by Venus Express during 6 years of orbital observations. The advances in numerical modeling are due to the use of updated catalogues of spectral lines of the atmospheric gases and recently developed fast and accurate methods of radiative flux calculations. This paper will summarize relevant data sets and will present a plan for updating of the corresponding chapter of the VIRA model.

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

    NASA Astrophysics Data System (ADS)

    Trujillo Bueno, J.

    2012-12-01

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

  19. Influence of the radiation pressure on the planetary exospheres: density profiles, escape flux and atmospheric stability

    NASA Astrophysics Data System (ADS)

    Beth, A.; Garnier, P.; Toublanc, D.; Dandouras, I.; Mazelle, C.

    2015-10-01

    The uppermost layer of the atmosphere, the exosphere,is not well-known in its global structure since the densities are very low compared to instrument detection capabilities. Because of rare collisions and high Knudsen numbers, the motion of light species (H,H2, ...)in the corona is essentially determined by the external forces : the gravitation from the planet, the radiation pressure, as well the stellar gravity. In this work, we calculate rigorously and analytically,based on the Hamiltonian mechanics and Liouville theorem, the impact of the radiation pressure and gravitation from the planet on the structure of the exosphere. This approach was partially used by Bishop and Chamberlain (1989) but only in the 2D case : we extend it to the 3D case. Assuming a collisionless exosphere and a constant radiation pressure near the planet, we determine the density profiles for ballistic particles (the main contribution for densities in the lower exosphere) for light species as a function of the angle with respect to the Sun direction. We also obtain an analytical formula for the escape flux at the subsolar point, which can be compared with the Jeans' escape flux. Finally, we study the effect of the radiation pressure on the zero velocity curves, position of the Roche lobe and Hill's region for the well-known Three-Body problem especially for Hot Jupiters and discuss about the validity of our model. The goal is to bring some constraints on modelling of exoplanet atmospheres.

  20. Simulating contemporary and preindustrial atmospheric chemistry and aerosol radiative forcing in the Southeast Pacific (Invited)

    NASA Astrophysics Data System (ADS)

    Spak, S.; Mena-Carrasco, M.; Carmichael, G. R.

    2010-12-01

    Accurately quantifying the aerosol burden and resultant radiative impacts over the Southeast Pacific presents a critical challenge in constraining the region's upper ocean heat budget and sea surface temperatures. Recent observations and preliminary modeling studies have found consistent aerosol transport above the region's extensive stratoculumus, indicating the need to consider aerosol composition and direct radiative effects in addition to indirect effects on clouds. We simulate regional chemical transport of aerosols and trace gases during VOCALS REx, identifying contributions from coastal anthropogenic emissions, biogenic emissions, biomass burning, and long-range transport to aerosol mass and composition. We evaluate a new emissions inventory through comparison with in-situ observations. Spatial and temporal variability in transport from these varied emissions sources provide insights into land-ocean-atmosphere coupling. We will compare aerosol radiative forcing under present day and preindustrial emissions rates.

  1. Fluctuations of energy density of short-pulse optical radiation in the turbulent atmosphere.

    PubMed

    Banakh, V A; Smalikho, I N

    2014-09-22

    Fluctuations of energy density of short-pulse optical radiation in the turbulent atmosphere have been studied based on numerical solution of the parabolic wave equation for the complex spectral amplitude of the wave field by the split-step method. It has been shown that under conditions of strong optical turbulence, the relative variance of energy density fluctuations of pulsed radiation of femtosecond duration becomes much less than the relative variance of intensity fluctuations of continuous-wave radiation. The spatial structure of fluctuations of the energy density with a decrease of the pulse duration becomes more large-scale and homogeneous. For shorter pulses the maximal value of the probability density distribution of energy density fluctuations tends to the mean value of the energy density.

  2. Absorption of Solar Radiation by the Cloudy Atmosphere: Further Interpretations of Collocated Aircraft Measurements

    NASA Technical Reports Server (NTRS)

    Cess, R. D.; Zhang, Minghua; Valero, Francisco P. J.; Pope, Shelly K.; Bucholtz, Anthony; Bush, Brett; Zender, Charles S.

    1998-01-01

    We have extended the interpretations made in two prior studies of the aircraft shortwave radiation measurements that were obtained as part of the Atmospheric Radiation Measurements (ARM) Enhanced Shortwave Experiments (ARESE). These extended interpretations use the 500 nm (10 nm bandwidth) measurements to minimize sampling errors in the broadband measurements. It is indicated that the clouds present during this experiment absorb more shortwave radiation than predicted by clear skies and thus by theoretical models, that at least some (less than or equal to 20%) of this enhanced cloud absorption occurs at wavelengths less than 680 nm, and that the observed cloud absorption does not appear to be an artifact of sampling errors nor of instrument calibration errors.

  3. Elevated atmospheric CO2 levels affect community structure of rice root-associated bacteria

    PubMed Central

    Okubo, Takashi; Liu, Dongyan; Tsurumaru, Hirohito; Ikeda, Seishi; Asakawa, Susumu; Tokida, Takeshi; Tago, Kanako; Hayatsu, Masahito; Aoki, Naohiro; Ishimaru, Ken; Ujiie, Kazuhiro; Usui, Yasuhiro; Nakamura, Hirofumi; Sakai, Hidemitsu; Hayashi, Kentaro; Hasegawa, Toshihiro; Minamisawa, Kiwamu

    2015-01-01

    A number of studies have shown that elevated atmospheric CO2 ([CO2]) affects rice yields and grain quality. However, the responses of root-associated bacteria to [CO2] elevation have not been characterized in a large-scale field study. We conducted a free-air CO2 enrichment (FACE) experiment (ambient + 200 μmol.mol−1) using three rice cultivars (Akita 63, Takanari, and Koshihikari) and two experimental lines of Koshihikari [chromosome segment substitution and near-isogenic lines (NILs)] to determine the effects of [CO2] elevation on the community structure of rice root-associated bacteria. Microbial DNA was extracted from rice roots at the panicle formation stage and analyzed by pyrosequencing the bacterial 16S rRNA gene to characterize the members of the bacterial community. Principal coordinate analysis of a weighted UniFrac distance matrix revealed that the community structure was clearly affected by elevated [CO2]. The predominant community members at class level were Alpha-, Beta-, and Gamma-proteobacteria in the control (ambient) and FACE plots. The relative abundance of Methylocystaceae, the major methane-oxidizing bacteria in rice roots, tended to decrease with increasing [CO2] levels. Quantitative PCR revealed a decreased copy number of the methane monooxygenase (pmoA) gene and increased methyl coenzyme M reductase (mcrA) in elevated [CO2]. These results suggest elevated [CO2] suppresses methane oxidation and promotes methanogenesis in rice roots; this process affects the carbon cycle in rice paddy fields. PMID:25750640

  4. A study of the 3D radiative transfer effect in cloudy atmospheres

    NASA Astrophysics Data System (ADS)

    Okata, M.; Teruyuki, N.; Suzuki, K.

    2015-12-01

    Evaluation of the effect of clouds in the atmosphere is a significant problem in the Earth's radiation budget study with their large uncertainties of microphysics and the optical properties. In this situation, we still need more investigations of 3D cloud radiative transer problems using not only models but also satellite observational data.For this purpose, we have developed a 3D-Monte-Carlo radiative transfer code that is implemented with various functions compatible with the OpenCLASTR R-Star radiation code for radiance and flux computation, i.e. forward and backward tracing routines, non-linear k-distribution parameterization (Sekiguchi and Nakajima, 2008) for broad band solar flux calculation, and DM-method for flux and TMS-method for upward radiance (Nakajima and Tnaka 1998). We also developed a Minimum cloud Information Deviation Profiling Method (MIDPM) as a method for a construction of 3D cloud field with MODIS/AQUA and CPR/CloudSat data. We then selected a best-matched radar reflectivity factor profile from the library for each of off-nadir pixels of MODIS where CPR profile is not available, by minimizing the deviation between library MODIS parameters and those at the pixel. In this study, we have used three cloud microphysical parameters as key parameters for the MIDPM, i.e. effective particle radius, cloud optical thickness and top of cloud temperature, and estimated 3D cloud radiation budget. We examined the discrepancies between satellite observed and mode-simulated radiances and three cloud microphysical parameter's pattern for studying the effects of cloud optical and microphysical properties on the radiation budget of the cloud-laden atmospheres.

  5. The annual radiation balance of the earth-atmosphere system during 1969-70 from Nimbus 3 measurements.

    NASA Technical Reports Server (NTRS)

    Raschke, E.; Vonder Haar, T. H.; Bandeen, W. R.; Pasternak , M.

    1973-01-01

    Measurements of reflected solar radiation and emitted thermal radiation taken with a radiometer on the meteorological satellite Nimbus 3 during 10 semi-monthly periods (April-15 August, 3-17 October, 1969; 21 January-3 February, 1970) provided for the first time high-resolution data on the earth's annual global radiation budget. Results on the planetary albedo, the amount of absorbed solar radiation, the infrared radiation loss to space, and the radiation balance of the earth-atmosphere system are discussed at various scales: global, hemispherical, and zonal averages; as well as global and polar maps with a spatial resolution of about synoptic scale.

  6. The Refurbishment and Upgrade of the Atmospheric Radiation Measurement Raman Lidar

    SciTech Connect

    Turner, D.D.; Goldsmith, J.E.M.

    2005-03-18

    The Atmospheric Radiation Measurement Program (ARM) Climate Research Facility (ACRF) Raman lidar (CARL) is an autonomous, turn-key system that profiles water vapor, aerosols, and clouds throughout the diurnal cycle for days without attention (Goldsmith et al. 1998). CARL was first deployed to the Southern Great Plains CRF during the summer of 1996 and participated in the 1996 and 1997 water vapor intensive operational periods (IOPs). Since February 1998, the system has collected over 38,000 hrs of data (equivalent of almost 4.4 years), with an average monthly uptime of 62% during this time period. This unprecedented performance by CARL makes it the premier operational Raman lidar in the world. Unfortunately, CARL began degrading in early 2002. This loss of sensitivity, which affected all observed variables, was very gradual and thus was not identified until the autumn of 2003. Analysis of the data suggested the problem was not associated with the laser or transmit portion of the system, but rather in the detection subsystem, as both the background values and the peak signals showed a marked decreases over this time period. The loss of sensitivity of a factor of 2-4, depending on the channel, resulted in higher random error in the retrieved products, such as the aerosol backscatter coefficient and water vapor mixing ratio. Figure 1 shows the random error at 2 km for aerosol backscatter coefficient (top) and water vapor mixing ratio (middle), in terms of percent of the signal for both average daytime (red) and nighttime (blue) data from 1998 to 2005. The seasonal variation of water vapor is easily seen in the random error in the water vapor mixing ratio data. The loss of sensitivity also affected the maximum range of the usable data, as illustrated by the dramatic decrease in the maximum height seen in the water vapor mixing ratio data (bottom). This degradation, which results in much larger random errors, greatly hinders the analysis of data sets such as the Aerosol

  7. An objective definition of air mass types affecting Athens, Greece; the corresponding atmospheric pressure patterns and air pollution levels.

    PubMed

    Sindosi, O A; Katsoulis, B D; Bartzokas, A

    2003-08-01

    This work aims at defining characteristic air mass types that dominate in the region of Athens, Greece during the cold (November-March) and the warm (May-September) period of the year and also at evaluating the corresponding concentration levels of the main air pollutants. For each air mass type, the mean atmospheric pressure distribution (composite maps) over Europe and the Mediterranean is estimated in order to reveal the association of atmospheric circulation with air pollution levels in Athens. The data basis for this work consists of daily values of thirteen meteorological and six pollutant parameters covering the period 1993-97. The definition of the characteristic air mass types is attempted objectively by using the methods of Factor Analysis and Cluster Analysis. The results show that during the cold period of the year there are six prevailing air mass types (at least 3% of the total number of days) and six infrequent ones. The examination of the corresponding air pollution concentration levels shows that the primary air pollutants appear with increased concentrations when light or southerly winds prevail. This is usually the case when a high pressure system is located over the central Mediterranean or a low pressure system lays over south Italy, respectively. Low levels of the primary pollutants are recorded under northeasterly winds, mainly caused by a high pressure system over Ukraine. During the warm period of the year, the southwestern Asia thermal low and the subtropical anticyclone of the Atlantic Ocean affect Greece. Though these synoptic systems cause almost stagnant conditions, four main air mass types are dominant and ten others, associated with extreme weather, are infrequent. Despite the large amounts of total solar radiation characterizing this period, ozone concentrations remain at low levels in central Athens because of its destruction by nitric oxide.

  8. Radiative energy balance of Venus based on improved models of the middle and lower atmosphere

    NASA Astrophysics Data System (ADS)

    Haus, R.; Kappel, D.; Tellmann, S.; Arnold, G.; Piccioni, G.; Drossart, P.; Häusler, B.

    2016-07-01

    The distribution of sources and sinks of radiative energy forces the atmospheric dynamics. The radiative transfer simulation model described by Haus et al. (2015b) is applied to calculate fluxes and temperature change rates in the middle and lower atmosphere of Venus (0-100 km) covering the energetic significant spectral range 0.125-1000 μm. The calculations rely on improved models of atmospheric parameters (temperature profiles, cloud parameters, trace gas abundances) retrieved from Venus Express (VEX) data (mainly VIRTIS-M-IR, but also VeRa and SPICAV/SOIR with respect to temperature results). The earlier observed pronounced sensitivity of the radiative energy balance of Venus to atmospheric parameter variations is confirmed, but present detailed comparative analyses of possible influence quantities ensure unprecedented insights into radiative forcing on Venus by contrast with former studies. Thermal radiation induced atmospheric cooling rates strongly depend on temperature structure and cloud composition, while heating rates are mainly sensitive to insolation conditions and UV absorber distribution. Cooling and heating rate responses to trace gas variations and cloud mode 1 abundance changes are small, but observed variations of cloud mode 2 abundances and altitude profiles reduce cooling at altitudes 65-80 km poleward of 50°S by up to 30% compared to the neglect of cloud parameter changes. Cooling rate variations with local time below 80 km are in the same order of magnitude. Radiative effects of the unknown UV absorber are modeled considering a proxy that is based on a suitable parameterization of optical properties, not on a specific chemical composition, and that is independent of the used cloud model. The UV absorber doubles equatorial heating near 68 km. Global average radiative equilibrium at the top of atmosphere (TOA) is characterized by the net flux balance of 156 W/m2, the Bond albedo of 0.76, and the effective planetary emission temperature of 228

  9. Radiative Transfer Model in the Atmosphere and Experimental Solar Data of Yaounde Location

    NASA Astrophysics Data System (ADS)

    Dountio, E. G.; Njomo, D.; Fouda, E.; Simo, A.

    2006-11-01

    The Sun is the primary source of energy supplying the Earth. This energy absorbed by the various components of the atmosphere, the oceans, the vegetation and Earth’s surface, is at the origin of the forces that control the climatic changes, the general circulation of the atmosphere, the temperature of the atmosphere and that of the oceans and the ionization of atmospheric gases, etc. The solar energy received on Earth’s surface is also directly used in technological applications such as solar heaters, solar dryers and other solar distillers, and the photovoltaic generators, etc. The calculation of the thermal performances of these apparatuses can be well made only if the spectral and even angular distribution of the solar irradiation arriving on the ground surface is well known. Moreover, the well known characteristics of the solar radiation arriving on the ground could inform us about the atmospheric phenomena that influenced its transfer, and consequently provide a better correction of the sensors response while receiving a signal from outer space in its direction, or the correction to be made on the response of a sensor while receiving data from a terrestrial sender. Only a few measurement stations of solar radiation are currently running and are not well managed, particularly in developing countries where the maintenance of a park of pyranometers on the ground is difficult and expensive. Moreover, where these measurements exist, they are rarely carried out for various wavelengths and/or angles. Such data are on the other hand accessible by numerical calculation, by solving the radiative transfer equation (ETR) in the atmosphere. One of the major factors attenuating the solar radiation received on the ground is scattering by clouds. The non- homogeneous nature of the clouds justifies the difficulty shown by the researchers to insert realistic profiles of clouds in radiative transfer models in a parallel stratified atmosphere [1, 2]. Several recent studies

  10. Photosynthesis of Quercus suber is affected by atmospheric NH3 generated by multifunctional agrosystems.

    PubMed

    Pintó-Marijuan, Marta; Da Silva, Anabela Bernardes; Flexas, Jaume; Dias, Teresa; Zarrouk, Olfa; Martins-Loução, Maria Amélia; Chaves, Maria Manuela; Cruz, Cristina

    2013-12-01

    Montados are evergreen oak woodlands dominated by Quercus species, which are considered to be key to biodiversity conservation and ecosystem services. This ecosystem is often used for cattle breeding in most regions of the Iberian Peninsula, which causes plants to receive extra nitrogen as ammonia (NH(3)) through the atmosphere. The effect of this atmospheric NH(3) (NH(3atm)) on ecosystems is still under discussion. This study aimed to evaluate the effects of an NH(3atm) concentration gradient downwind of a cattle barn in a Montado area. Leaves from the selected Quercus suber L. trees along the gradient showed a clear influence of the NH(3) on δ(13)C, as a consequence of a strong limitation on the photosynthetic machinery by a reduction of both stomatal and mesophyll conductance. A detailed study of the impact of NH(3atm) on the photosynthetic performance of Q. suber trees is presented, and new mechanisms by which NH(3) affects photosynthesis at the leaf level are suggested.

  11. Atmospheric Teleconnection over Eurasia Induced by Aerosol Radiative Forcing During Boreal Spring

    NASA Technical Reports Server (NTRS)

    Kim, Maeng-Ki; Lau, K. M.; Chin, Mian; Kim, Kyu-Myong; Sud, Y. C.; Walker, Greg K.

    2005-01-01

    The direct effects of aerosols on global and regional climate during boreal spring are investigated based on simulations using the NASA Global Modeling and Assimilation Office (GMAO) finite-volume general circulation model (fvGCM) with Microphyics of clouds in Relaxed Arakawa Schubert Scheme (McRAS). The aerosol loading are prescribed from three-dimensional monthly distribution of tropospheric aerosols viz., sulfate, black carbon, organic carbon, soil dust, and sea salt from output of the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The aerosol extinction coefficient, single scattering albedo, and asymmetric factor are computed as wavelength-dependent radiative forcing in the radiative transfer scheme of the fvGCM, and as a function of the aerosol loading and ambient relative humidity. We find that anomalous atmospheric heat sources induced by absorbing aerosols (dust and black carbon) excites a planetary scale teleconnection pattern in sea level pressure, temperature and geopotential height spanning North Africa through Eurasia to the North Pacific. Surface cooling due to direct effects of aerosols is found in the vicinity and downstream of the aerosol source regions, i.e., South Asia, East Asia, and northern and western Africa. Additionally, atmospheric heating is found in regions with large loading of dust (over Northern Africa, and Middle East), and black carbon (over South-East Asia). Paradoxically, the most pronounced feature in aerosol-induced surface temperature is an east-west dipole anomaly with strong cooling over the Caspian Sea, and warming over central and northeastern Asia, where aerosol concentration are low. Analyses of circulation anomalies show that the dipole anomaly is a part of an atmospheric teleconnection driven by atmospheric heating anomalies induced by absorbing aerosols in the source regions, but the influence was conveyed globally through barotropic energy dispersion and sustained by feedback processes

  12. Processes affecting oxygen isotope ratios of atmospheric and ecosystem sulfate in two contrasting forest catchments in Central Europe.

    PubMed

    Novák, Martin; Mitchell, Myron J; Jacková, Iva; Buzek, Frantisek; Schweigstillová, Jana; Erbanová, Lucie; Prikryl, Richard; Fottová, Daniela

    2007-02-01

    Sulfate aerosols are harmful as respirable particles. They also play a role as cloud condensation nuclei and have radiative effects on global climate. A combination of delta18O-SO4 data with catchment sulfur mass balances was used to constrain processes affecting S cycling in the atmosphere and spruce forests of the Czech Republic. Extremely high S fluxes via spruce throughfall and runoff were measured at Jezeri (49 and 80 kg S ha(-1) yr(-1), respectively). The second catchment, Na Lizu, was 10 times less polluted. In both catchments, delta18O-SO4 decreased in the following order: open-area precipitation > throughfall > runoff. The delta18O-SO4 values of throughfall exhibited a seasonal pattern at both sites, with maxima in summer and minima in winter. This seasonal pattern paralleled delta18O-H2O values, which were offset by -18 per thousand. Sulfate in throughfall was predominantly formed by heterogeneous (aqueous) oxidation of SO2. Wet-deposited sulfate in an open area did not show systematic delta18O-SO4 trends, suggesting formation by homogeneous (gaseous) oxidation and/or transport from large distances. The percentage of incoming S that is organically cycled in soil was similar under the high and the low pollution. High-temperature 18O-rich sulfate was not detected, which contrasts with North American industrial sites.

  13. Cloud radiative forcing induced by layered clouds and associated impact on the atmospheric heating rate

    NASA Astrophysics Data System (ADS)

    Lü, Qiaoyi; Li, Jiming; Wang, Tianhe; Huang, Jianping

    2015-10-01

    A quantitative analysis of cloud fraction, cloud radiative forcing, and cloud radiative heating rate (CRH) of the single-layered cloud (SLC) and the multi-layered cloud (MLC), and their differences is presented, based on the 2B-CLDCLASS-LIDAR and 2B-FLXHR-LIDAR products on the global scale. The CRH at a given atmospheric level is defined as the cloudy minus clear-sky radiative heating rate. The statistical results show that the globally averaged cloud fraction of the MLC (24.9%), which is primarily prevalent in equatorial regions, is smaller than that of the SLC (46.6%). The globally averaged net radiative forcings (NET CRFs) induced by the SLC (MLC) at the top and bottom of the atmosphere (TOA and BOA) and in the atmosphere (ATM) are-60.8 (-40.9),-67.5 (-49.6), and 6.6 (8.7) W m-2, respectively, where the MLC contributes approximately 40.2%, 42.4%, and 57% to the NET CRF at the TOA, BOA, and in the ATM, respectively. The MLC exhibits distinct differences to the SLC in terms of CRH. The shortwave CRH of the SLC (MLC) reaches a heating peak at 9.75 (7.5) km, with a value of 0.35 (0.60) K day-1, and the differences between SLC and MLC transform from positive to negative with increasing altitude. However, the longwave CRH of the SLC (MLC) reaches a cooling peak at 2 (8) km, with a value of-0.45 (-0.42) K day-1, and the differences transform from negative to positive with increasing altitude. In general, the NET CRH differences between SLC and MLC are negative below 7.5 km. These results provide an observational basis for the assessment and improvement of the cloud parameterization schemes in global models.

  14. Radiative Impacts of Cloud Heterogeneity and Overlap in an Atmospheric General Circulation Model

    NASA Technical Reports Server (NTRS)

    Oreopoulos, L.; Lee, D.; Sud, Y. C.; Suarez, M. J.

    2012-01-01

    The radiative impacts of introducing horizontal heterogeneity of layer cloud condensate, and vertical overlap of condensate and cloud fraction are examined with the aid of a new radiation package operating in the GEOS-5 Atmospheric General Circulation Model. The impacts are examined in terms of diagnostic top-of-the-atmosphere shortwave (SW) and longwave (LW) cloud radiative effect (CRE) calculations for a range of assumptions and parameter specifications about the overlap. The investigation is conducted for two distinct cloud schemes, the one that comes with the standard GEOS-5 distribution, and another which has been recently used experimentally for its enhanced GEOS-5 distribution, and another which has been recently used experimentally for its enhanced cloud microphysical capabilities; both are coupled to a cloud generator allowing arbitrary cloud overlap specification. We find that cloud overlap radiative impacts are significantly stronger for the operational cloud scheme for which a change of cloud fraction overlap from maximum-random to generalized results to global changes of SW and LW CRE of approximately 4 Watts per square meter, and zonal changes of up to approximately 10 Watts per square meter. This is because of fewer occurrences compared to the other scheme of large layer cloud fractions and of multi-layer situations with large numbers of atmospheric being simultaneously cloudy, conditions that make overlap details more important. The impact on CRE of the details of condensate distribution overlap is much weaker. Once generalized overlap is adopted, both cloud schemes are only modestly sensitive to the exact values of the overlap parameters. We also find that if one of the CRE components is overestimated and the other underestimated, both cannot be driven towards observed values by adjustments to cloud condensate heterogeneity and overlap alone.

  15. Radiative Susceptibility of Cloudy Atmospheres to Droplet Number Perturbations: 1. Theoretical Analysis and Examples from MODIS

    NASA Technical Reports Server (NTRS)

    Platnick, Steven; Oreopoulos, Lazaros

    2008-01-01

    Theoretical and satellite-based assessments of the sensitivity of broadband shortwave radiative fluxes in cloudy atmospheres to small perturbations in the cloud droplet number concentration (N) of liquid water clouds under constant water conditions are performed. Two approaches to study this sensitivity are adopted: absolute increases in N, for which the radiative response is referred to as absolute cloud susceptibility, and relative increases in N or relative cloud susceptibility. Estimating the former is more challenging as it requires an assumed value for either cloud liquid water content or geometrical thickness; both susceptibilities require an assumed relationship between the droplet volume and effective radius. Expanding upon previous susceptibility studies, present radiative calculations include the effect of AN perturbations on droplet asymmetry parameter and single-scattering albedo, in addition to extinction. Absolute cloud susceptibility has a strong nonlinear dependence on the droplet effective radius as expected, while relative cloud susceptibility is primarily dependent on optical thickness. Molecular absorption and reflecting surfaces both reduce the relative contribution of the cloud to the top-of-atmosphere (TOA) flux and therefore also reduce the TOA albedo susceptibility. Transmittance susceptibilities are negative with absolute values similar to albedo susceptibility, while atmospheric absorptance susceptibilities are about an order of magnitude smaller than albedo susceptibilities and can be either positive or negative. Observation-based susceptibility calculations are derived from MODIS pixel-level retrievals of liquid water cloud optical thickness, effective radius, and cloud top temperature; two data granule examples are shown. Susceptibility quantifies the aerosol indirect effect sensitivity in a way that can be easily computed from model fields. As such, susceptibilities derived from MODIS observations provide a higher-order test of model

  16. Final Technical Report. Cloud and Radiation Testbed (CART) Raman Lidar measurement of atmospheric aerosols for the Atmospheric Radiation Measurement (ARM) Program

    SciTech Connect

    Ferrare, Richard A.

    2002-08-19

    Vertical profiles of aerosol extinction are required for determination of the effects of aerosols on the clear-sky radiative flux. Since recent studies have demonstrated the inability to compute these profiles on surface aerosol measurements alone, vertical profiles of aerosol optical properties must be acquired to compute aerosol radiative effects throughout the entire atmospheric column. Following the recommendation of the ARM Aerosol Working Group, the investigator developed, evaluated, and implemented algorithms for the CART Raman Lidar to provide profiles of aerosol extinction and backscattering. By virtue of its ability to measure vertical profiles of both aerosol extinction and water vapor simultaneously in the same scattering volume, we used the resulting profiles from the CART Raman Lidar to investigate the impact of water vapor and relative humidity on aerosol extinction throughout the column on a continuous and routine basis. The investigator used these the CART Raman Lidar aerosol extinction and backscattering profiles to evaluate the vertical variability of aerosol extinction and the extinction/backscatter ratio over the ARM SGP site.

  17. 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.

  18. A simplified method for calculating the atmospheric heating rate by absorption of solar radiation in the stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Shimazaki, T.; Helmle, L. C.

    1979-01-01

    Calculations of the atmospheric heating rate by absorption of solar radiation by O3, H2O, and CO2 are reported. The method needs only seven parameters for each molecule and is particularly useful for heating calculations in three-dimensional global circulation models below 80 km. Applying the formula to the observed distributions of O3, H2O, and CO2 produces reasonable latitudinal and seasonal variations in the heating rate. The calculated heating rate, however, is sensitive to the global distributions of the absorbing gases, and uncertainties in the O3 distribution above approximately 50 km and the H2O distribution below approximately 20 km may seriously affect the global distributions of the heating rate in these regions.

  19. Scientific Infrastructure to Support Atmospheric Science and Aerosol Science for the Department of Energy's Atmospheric Radiation Measurement Programs at Barrow, Alaska.

    NASA Astrophysics Data System (ADS)

    Lucero, D. A.; Ivey, M.; Helsel, F.; Hardesty, J.; Dexheimer, D.

    2015-12-01

    Scientific infrastructure to support atmospheric science and aerosol science for the Department of Energy's Atmospheric Radiation Measurement programs at Barrow, Alaska.The Atmospheric Radiation Measurement (ARM) Program's located at Barrow, Alaska is a U.S. Department of Energy (DOE) site. The site provides a scientific infrastructure and data archives for the international Arctic research community. The infrastructure at Barrow has been in place since 1998, with many improvements since then. Barrow instruments include: scanning precipitation Radar-cloud radar, Doppler Lidar, Eddy correlation flux systems, Ceilometer, Manual and state-of-art automatic Balloon sounding systems, Atmospheric Emitted Radiance Interferometer (AERI), Micro-pulse Lidar (MPL), Millimeter cloud radar, High Spectral Resolution Lidar (HSRL) along with all the standard metrological measurements. Data from these instruments is placed in the ARM data archives and are available to the international research community. This poster will discuss what instruments are at Barrow and the challenges of maintaining these instruments in an Arctic site.

  20. Evaluation of the Multi-Scale Modeling Framework using Data from the Atmospheric Radiation Measurement Program

    SciTech Connect

    Ovchinnikov, Mikhail; Ackerman, Thomas P.; Marchand, Roger T.; Khairoutdinov, Marat

    2004-07-01

    One of the goals of the Atmospheric Radiation Measurement (ARM) program was to provide long-term observations for evaluation of cloud and radiation treatment in global climate models. Unfortunately, traditional parametric approach of diagnosing cloud and radiation properties from large-scale model fields is not well suited for comparison with observed time series at selected locations. A recently emerging approach called the multi-scale modeling framework (MMF) has shown promise to bridge the gap. MMF consists of a two-dimensional cloud system resolving model (CSRM) embedded into each CAM grid column of the Community Atmospheric Model (CAM), thereby computing cloud properties at a scale that is more consistent with observations. Because the approach is computationally expensive only limited simulations have been carried out. In this presentation, we will present a comparison of data from two ARM sites, one at the Southern Great Plains (SGP) in Oklahoma and one at Nauru island in the Tropical Western Pacific (TWP) region, with output from both CAM and MMF. Two sets of one year long simulations are considered: one using climatological sea surface temperatures (SST) and another using 1999 SST. Each set includes a run with MMF as well as CAM run with traditional or standard cloud and radiation treatment. Time series of cloud fraction, precipitation intensity, and downwelling solar radiation flux at the surface are statistically analyzed. For the TWP site, nearly all parameters of frequency distributions of these variables from MMF run are shown to be more consistent with observation than those from CAM run. For the SGP, the improvements are marginal.

  1. Daily spectral effects on concentrating PV solar cells as affected by realistic aerosol optical depth and other atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Gueymard, Christian A.

    2009-08-01

    This contribution addresses the need for more information about the spectral effect affecting solar cells specifically designed for concentrating photovoltaic (CPV) applications. Spectral effects result from differences between the actual (dynamically variable) solar spectrum incident on a solar cell in the field and the standard (fixed) solar spectrum used for rating purposes. A methodology is proposed to quantify this spectral effect at any site where basic atmospheric information exists, and predict what semiconductor material(s) may benefit from operating under non-standard conditions. Using the same SMARTS radiative code as for the development of the improved reference spectrum for concentrating PV rating, an analysis of the spectral sensitivity of five specific PV technologies to varying atmospheric factors is presented, using simulated spectra at 5-nm resolution. (The alternative of using the average photon energy (APE) concept was also considered, but proved inappropriate in the present context.) The technologies investigated here include a 21.5%-efficient CIGS cell, a 22%-efficient crystalline silicon cell (both appropriate for low-concentration applications), as well as three high-performance multijunction cells, which are specifically designed for high-concentration applications. To the difference of most previous studies, the approach taken here considers realistic atmospheric conditions. The proposed Daily Spectral Enhancement Factor (DSEF) is obtained from a typical daily-average incident spectrum, which is purposefully weighted to minimize the incidence of large spectral effects at low sun. Calculations of DSEF are performed here at fifteen world sites from an atmospheric monitoring network. These sites have largely different latitudes and climates, and yet are all potentially interesting for CPV applications. Results are obtained for a typical clear day of January and July, and for each of the five PV technologies just mentioned. This analysis

  2. Exoplanet Atmospheres: From Light-Curve Analyses to Radiative-Transfer Modeling

    NASA Astrophysics Data System (ADS)

    Cubillos, Patricio; Harrington, Joseph; Blecic, Jasmina; Rojo, Patricio; Stemm, Madison; Lust, Nathaniel B.; Foster, Andrew S.; Loredo, Thomas J.

    2015-01-01

    Multi-wavelength transit and secondary-eclipse light-curve observations are some of the most powerful techniques to probe the thermo-chemical properties of exoplanets. Although the small planet-to-star constrast ratios demand a meticulous data analysis, and the limited available spectral bands can further restrain constraints, a Bayesian approach can robustly reveal what constraints can we set, given the data.We review the main aspects considered during the analysis of Spitzer time-series data by our group with an aplication to WASP-8b and TrES-1. We discuss the applicability and limitations of the most commonly used correlated-noise estimators. We describe our open-source Bayesian Atmospheric Radiative Transfer (BART) code. BART calculates the planetary emission or transmission spectrum by solving a 1D line-by-line radiative-transfer equation. The generated spectra are integrated over determined bandpasses for comparison to the data. Coupled to our Multi-core Markov-chain Monte Carlo (MC3) statistical package, BART constrains the temperature profile and chemical abundances in the planet's atmosphere. We apply the BART retrieval code to the HD 209458b data set to estimate the planet's temperature profile and molecular abundances.This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

  3. Atmospheric Radiation Measurement (ARM) Data from the ARM Specific Measurement Categories

    DOE Data Explorer

    The ARM Program gathers a wide variety of measurements from many different sources. Each day, the Data Archive stores and distributes large quantities of data collected from these sources. Scientists then use these data to research atmospheric radiation balance and cloud feedback processes, which are critical elements of global climate change. The huge archive of ARM data can be organized by measurement categories into six "collections:" Aerosols, Atmospheric Carbon, Atmospheric State, Cloud Properties, Radiometric, and Surface Properties. Clicking on one of the measurement categories leads to a page that breaks that category down into sub-categories. For example, "Aerosols" is broken down into Microphysical and Chemical Properties (with 9 subsets) and Optical and Radiative Properties (with 7 subsets). Each of the subset links, in turn, leads to detailed information pages and links to specific data streams. Users will be requested to create a password, but the data files are free for viewing and downloading. The ARM Archive physically resides at the Oak Ridge National Laboratory.

  4. MOCRA: a Monte Carlo code for the simulation of radiative transfer in the atmosphere.

    PubMed

    Premuda, Margherita; Palazzi, Elisa; Ravegnani, Fabrizio; Bortoli, Daniele; Masieri, Samuele; Giovanelli, Giorgio

    2012-03-26

    This paper describes the radiative transfer model (RTM) MOCRA (MOnte Carlo Radiance Analysis), developed in the frame of DOAS (Differential Optical Absorption Spectroscopy) to correctly interpret remote sensing measurements of trace gas amounts in the atmosphere through the calculation of the Air Mass Factor. Besides the DOAS-related quantities, the MOCRA code yields: 1- the atmospheric transmittance in the vertical and sun directions, 2- the direct and global irradiance, 3- the single- and multiple- scattered radiance for a detector with assigned position, line of sight and field of view. Sample calculations of the main radiometric quantities calculated with MOCRA are presented and compared with the output of another RTM (MODTRAN4). A further comparison is presented between the NO2 slant column densities (SCDs) measured with DOAS at Evora (Portugal) and the ones simulated with MOCRA. Both comparisons (MOCRA-MODTRAN4 and MOCRA-observations) gave more than satisfactory results, and overall make MOCRA a versatile tool for atmospheric radiative transfer simulations and interpretation of remote sensing measurements.

  5. MOCRA: a Monte Carlo code for the simulation of radiative transfer in the atmosphere.

    PubMed

    Premuda, Margherita; Palazzi, Elisa; Ravegnani, Fabrizio; Bortoli, Daniele; Masieri, Samuele; Giovanelli, Giorgio

    2012-03-26

    This paper describes the radiative transfer model (RTM) MOCRA (MOnte Carlo Radiance Analysis), developed in the frame of DOAS (Differential Optical Absorption Spectroscopy) to correctly interpret remote sensing measurements of trace gas amounts in the atmosphere through the calculation of the Air Mass Factor. Besides the DOAS-related quantities, the MOCRA code yields: 1- the atmospheric transmittance in the vertical and sun directions, 2- the direct and global irradiance, 3- the single- and multiple- scattered radiance for a detector with assigned position, line of sight and field of view. Sample calculations of the main radiometric quantities calculated with MOCRA are presented and compared with the output of another RTM (MODTRAN4). A further comparison is presented between the NO2 slant column densities (SCDs) measured with DOAS at Evora (Portugal) and the ones simulated with MOCRA. Both comparisons (MOCRA-MODTRAN4 and MOCRA-observations) gave more than satisfactory results, and overall make MOCRA a versatile tool for atmospheric radiative transfer simulations and interpretation of remote sensing measurements. PMID:22453470

  6. Multiangle Implementation of Atmospheric Correction (MAIAC):. 1; Radiative Transfer Basis and Look-up Tables

    NASA Technical Reports Server (NTRS)

    Lyapustin, Alexei; Martonchik, John; Wang, Yujie; Laszlo, Istvan; Korkin, Sergey

    2011-01-01

    This paper describes a radiative transfer basis of the algorithm MAIAC which performs simultaneous retrievals of atmospheric aerosol and bidirectional surface reflectance from the Moderate Resolution Imaging Spectroradiometer (MODIS). The retrievals are based on an accurate semianalytical solution for the top-of-atmosphere reflectance expressed as an explicit function of three parameters of the Ross-Thick Li-Sparse model of surface bidirectional reflectance. This solution depends on certain functions of atmospheric properties and geometry which are precomputed in the look-up table (LUT). This paper further considers correction of the LUT functions for variations of surface pressure/height and of atmospheric water vapor, which is a common task in the operational remote sensing. It introduces a new analytical method for the water vapor correction of the multiple ]scattering path radiance. It also summarizes the few basic principles that provide a high efficiency and accuracy of the LUT ]based radiative transfer for the aerosol/surface retrievals and optimize the size of LUT. For example, the single-scattering path radiance is calculated analytically for a given surface pressure and atmospheric water vapor. The same is true for the direct surface-reflected radiance, which along with the single-scattering path radiance largely defines the angular dependence of measurements. For these calculations, the aerosol phase functions and kernels of the surface bidirectional reflectance model are precalculated at a high angular resolution. The other radiative transfer functions depend rather smoothly on angles because of multiple scattering and can be calculated at coarser angular resolution to reduce the LUT size. At the same time, this resolution should be high enough to use the nearest neighbor geometry angles to avoid costly three ]dimensional interpolation. The pressure correction is implemented via linear interpolation between two LUTs computed for the standard and reduced

  7. Atmospheric Radiation Measurement (ARM) Data from the North Slope Alaska (NSA) Site

    DOE Data Explorer

    The Atmospheric Radiation Measurement (ARM) Program is the largest global change research program supported by the U.S. Department of Energy. The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. To achieve this goal, ARM scientists and researchers around the world use continuous data obtained through the ARM Climate Research Facility. ARM maintains four major, permanent sites for data collection and deploys the ARM Mobile Facility to other sites as determined. The North Slope of Alaska (NSA) site is a permanent site providing data about cloud and radiative processes at high latitudes. These data are being used to refine models and parameterizations as they relate to the Arctic. Centered at Barrow and extending to the south (to the vicinity of Atqasuk), west (to the vicinity of Wainwright), and east (towards Oliktok), the NSA site has become a focal point for atmospheric and ecological research activity on the North Slope. Approximately 300,000 NSA data sets from 1993 to the present reside in the ARM Archive at http://www.archive.arm.gov/. Users will need to register for a password, but all files are then free for viewing or downloading. The ARM Archive physically resides at the Oak Ridge National Laboratory.

  8. Trends of solar radiation, cloudiness and atmospheric transparency during recent decades in Estonia

    NASA Astrophysics Data System (ADS)

    Russak, V.

    1990-04-01

    Data obtained during 1955 1986 at the Tôravere Actinometric Station (Estonia, USSR) are used to study the long-term variations of the direct (S') and global solar radiation (Q) at the earth's surface. During these years, a certain decreasing trend was observed both in S' and in Q (ΔS'= 13%, ΔQ= 6.8%). The results from Tôravere are compared with the data on global radiation acquired in 1964 1986 at 9 different actinometric stations in northern Europe (8) and western Siberia (1). Decreasing trends have been observed in Helsinki and Stockholm (ΔQ=-11%), and also in Kaunas (ΔQ=-12%) in the same period. The variations of the cloudiness regime and atmospheric transparency as the main reasons for the decrease of radiation are discussed. According to the measurement data from Tôravere, the mean annual amount of low clouds increased by 11%, whereas the value of the Bouguer atmospheric transparency coefficient decreased by 3.7%.

  9. Broadband Outdoor Radiometer Calibration Process for the Atmospheric Radiation Measurement Program

    SciTech Connect

    Dooraghi, Michael

    2015-09-01

    The Atmospheric Radiation Measurement program (ARM) maintains a fleet of monitoring stations to aid in the improved scientific understanding of the basic physics related to radiative feedback processes in the atmosphere, particularly the interactions among clouds and aerosols. ARM obtains continuous measurements and conducts field campaigns to provide data products that aid in the improvement and further development of climate models. All of the measurement campaigns include a suite of solar measurements. The Solar Radiation Research Laboratory at the National Renewable Energy Laboratory supports ARM's full suite of stations in a number of ways, including troubleshooting issues that arise as part of the data-quality reviews; managing engineering changes to the standard setup; and providing calibration services and assistance to the full fleet of solar-related instruments, including pyranometers, pyrgeometers, pyrheliometers, as well as the temperature/relative humidity probes, multimeters, and data acquisition systems that are used in the calibrations performed at the Southern Great Plains Radiometer Calibration Facility. This paper discusses all aspects related to the support provided to the calibration of the instruments in the solar monitoring fleet.

  10. Polarization of radiation of point-like source reflected from turbulent magnetized atmosphere

    NASA Astrophysics Data System (ADS)

    Silant'ev, N. A.; Gnedin, Yu. N.

    2008-04-01

    We consider the multiple scattering of the light from a point-like source located above the semi-infinite electron, turbulent, and magnetized atmospheres. The frozen magnetic field has both the regular B0 and stochastic B' components (B= B_0+ B'). The stochastic Faraday rotations due to fluctuations B' decrease the intensity of each separate polarized beam (the extinction factor is proportional to λ^4< B'^2>). This decrease at large λ dominates the usual decrease (∝λ^2B_0 cosΘ_0) caused by summing beams with very different Faraday's rotation angles. This effect changes the spectrum of polarization degree as compared with what is influenced by the regular magnetic field. We calculated the integral (observed) polarization of the reflected radiation with the inclusion of unpolarized radiation going directly from the point-like source. We present the observed polarization for various degrees of true absorption of the radiation into the atmosphere and the values of magnetic energy fluctuations. The spectra of polarization in the optical (λ =0-1 μm), infrared (λ =1-5 μ m), and X-ray (E=1-50 keV) regions of the wavelengths are presented. We discuss the possibility of estimating parameters of magnetic field fluctuations from the observation of the spectra of polarization in AGNs with the X-ray excesses and in the turbulent accretion disk in NGC 4258.

  11. Radiative transfer in the atmosphere-ocean system: the finite-element method.

    PubMed

    Bulgarelli, B; Kisselev, V B; Roberti, L

    1999-03-20

    The finite-element method has been applied to solving the radiative-transfer equation in a layered medium with a change in the refractive index, such as the atmosphere-ocean system. The physical processes that are included in the algorithm are multiple scattering, bottom-boundary bidirectional reflectivity, and refraction and reflection at the interface between the media with different refractive properties. The incident radiation is a parallel flux on the top boundary that is characteristic of illumination of the atmosphere by the Sun in the UV, visible, and near-IR regions of the electromagnetic spectrum. The necessary changes, compared with the case of a uniformly refracting layered medium, are described. An energy-conservation test has been performed on the model. The algorithm has also been validated through comparison with an equivalent backward Monte Carlo code and with data taken from the literature, and optimal agreement was shown. The results show that the model allows energy conservation independently of the adopted phase function, the number of grid points, and the relative refractive index. The radiative-transfer model can be applied to any other layered system with a change in the refractive index. The fortran code for this algorithm is documented and is available for applications. PMID:18305777

  12. Transport of Chemical Vapors from Subsurface Sources to Atmosphere as Affected by Shallow Subsurface and Atmospheric Conditions

    NASA Astrophysics Data System (ADS)

    Rice, A. K.; Smits, K. M.; Hosken, K.; Schulte, P.; Illangasekare, T. H.

    2012-12-01

    Understanding the movement and modeling of chemical vapor through unsaturated soil in the shallow subsurface when subjected to natural atmospheric thermal and mass flux boundary conditions at the land surface is of importance to applications such as landmine detection and vapor intrusion into subsurface structures. New, advanced technologies exist to sense chemical signatures at the land/atmosphere interface, but interpretation of these sensor signals to make assessment of source conditions remains a challenge. Chemical signatures are subject to numerous interactions while migrating through the unsaturated soil environment, attenuating signal strength and masking contaminant source conditions. The dominant process governing movement of gases through porous media is often assumed to be Fickian diffusion through the air phase with minimal or no quantification of other processes contributing to vapor migration, such as thermal diffusion, convective gas flow due to the displacement of air, expansion/contraction of air due to temperature changes, temporal and spatial variations of soil moisture and fluctuations in atmospheric pressure. Soil water evaporation and interfacial mass transfer add to the complexity of the system. The goal of this work is to perform controlled experiments under transient conditions of soil moisture, temperature and wind at the land/atmosphere interface and use the resulting dataset to test existing theories on subsurface gas flow and iterate between numerical modeling efforts and experimental data. Ultimately, we aim to update conceptual models of shallow subsurface vapor transport to include conditionally significant transport processes and inform placement of mobile sensors and/or networks. We have developed a two-dimensional tank apparatus equipped with a network of sensors and a flow-through head space for simulation of the atmospheric interface. A detailed matrix of realistic atmospheric boundary conditions was applied in a series of

  13. New calculations of the atmospheric cosmic radiation field--results for neutron spectra.

    PubMed

    Clem, J M; De Angelis, G; Goldhagen, P; Wilson, J W

    2004-01-01

    The propagation of primary cosmic rays through the Earth's atmosphere and the energy spectra of the resulting secondary particles have been calculated using the Monte Carlo transport code FLUKA with several novel auxiliary methods. Solar-modulated primary cosmic ray spectra were determined through an analysis of simultaneous proton and helium measurements made on spacecraft or high-altitude balloon flights. Primary protons and helium ions are generated within the rigidity range of 0.5 GV-20 TV, uniform in cos2theta. For a given location, primaries above the effective angle-dependent geomagnetic cut-off rigidity, and re-entrant albedo protons, are transported through the atmosphere. Helium ions are initially transported using a separate transport code called HEAVY to simulate fragmentation. HEAVY interfaces with FLUKA to provide interaction starting points for each nucleon originating from a helium nucleus. Calculated cosmic ray neutron spectra and consequent dosimetric quantities for locations with a wide range of altitude (atmospheric depth) and geomagnetic cut-off are presented and compared with measurements made on a high-altitude aeroplane. Helium ion propagation using HEAVY and inclusion of re-entrant albedo protons with the incident primary spectra significantly improved the agreement of the calculated cosmic ray neutron spectra with measured spectra. These cosmic ray propagation calculations provide the basis for a new atmospheric ionising radiation (AIR) model for air-crew dosimetry, calculation of effects on microelectronics, production of cosmogenic radionuclides and other uses. PMID:15353685

  14. The Exploration Atmospheres Working Group's Report on Space Radiation Shielding Materials

    NASA Technical Reports Server (NTRS)

    Barghouty, A. F.; Thibeault, S. A.

    2006-01-01

    This part of Exploration Atmospheres Working Group analyses focuses on the potential use of nonmetallic composites as the interior walls and structural elements exposed to the atmosphere of the spacecraft or habitat. The primary drive to consider nonmetallic, polymer-based composites as an alternative to aluminum structure is due to their superior radiation shielding properties. But as is shown in this analysis, these composites can also be made to combine superior mechanical properties with superior shielding properties. In addition, these composites can be made safe; i.e., with regard to flammability and toxicity, as well as "smart"; i.e., embedded with sensors for the continuous monitoring of material health and conditions. The analysis main conclusions are that (1) smart polymer-based composites are an enabling technology for safe and reliable exploration missions, and (2) an adaptive, synergetic systems approach is required to meet the missions requirements from structure, properties, and processes to crew health and protection for exploration missions.

  15. Polarimetry of hot-Jupiter systems and radiative transfer models of planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Bott, Kimberly; Bailey, Jeremy; Kedziora-Chudczer, Lucyna; Cotton, Daniel; Marshall, Jonathan

    2016-01-01

    Thousands of exoplanets and planet candidates have been detected. The next important step in the contexts of astrobiology, planetary classification and planet formation is to characterise them. My dissertation aims to provide further characterisation to four hot Jupiter exoplanets: the relatively well-characterised HD 189733b, WASP-18b which is nearly large enough to be a brown dwarf, and two minimally characterised non-transiting hot Jupiters: HD 179949b and tau Bootis b.For the transiting planets, this is done through two means. First, published data from previous observations of the secondary eclipse (and transit for HD 189733b) are compared to models created with the Versatile Software for the Transfer of Atmospheric Radiation (VSTAR). Second, new polarimetric observations from the HIgh Precision Polarimetric Instrument are compared to Lambert-Rayleigh polarised light phase curves. For the non-transiting planets, only the polarimetric measurements are compared to models, but toy radiative transfer models are produced for concept. As an introduction to radiative transfer models, VSTAR is applied to the planet Uranus to measure its D/H isotope ratio. A preliminary value is derived for D/H in one part of the atmosphere.Fitting a single atmospheric model to the transmitted, reflected, and emitted light, I confirm the presence of water on HD 189733b, and present a new temperature profile and cloud profile for the planet. For WASP-18b, I confirm the general shape of the temperature profile. No conclusions can be drawn from the polarimetric measurements for the non-transiting planets. I detect a possible variation with phase for transiting planet WASP-18b but cannot confirm it at this time. Alternative sources to the planet are discussed. For HD 189733b, I detect possible variability in the polarised light at the scale expected for the planet. However, the data are also statistically consistent with no variability and are not matched to the phase of the planet.

  16. Fire risk, atmospheric chemistry and radiative forcing assessment of wildfires in eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Athanasopoulou, E.; Rieger, D.; Walter, C.; Vogel, H.; Karali, A.; Hatzaki, M.; Gerasopoulos, E.; Vogel, B.; Giannakopoulos, C.; Gratsea, M.; Roussos, A.

    2014-10-01

    The current research study aims at investigating the atmospheric implications of a major fire event in the Mediterranean area. For this purpose, a regional aerosol model coupled online with meteorology (COSMO-ART) is applied over Greece during late summer 2007. Fire risk model results proved to be adequate in reproducing the highly destructive event, which supports further applications for national meteorological forecasts and early warning systems for fire prevention. Columnar aerosol loading field predictions are consistent with satellite maps, which further allows for the correlation of this wildfire event to the atmospheric chemistry and the radiative forcing. Gaseous chemistry resembles that in urban environments and led to nitrogen dioxide and ozone exceedances in several cities in proximity to and downwind the fire spots, respectively. Influence in Athens is found significant from the Euboean plume (45% of total surface PM10) and small (5%) from the fires in Peloponnese. Fire events are indicated by sharp increases in organic to elemental carbon (6), together with sharp decreases in secondary to total organic components (0.1), in comparison to their values during the pre- and post-fire period over Athens (1 and 0.6, respectively). The change in the radiative budget induced by the fire plume is found negative (3-day-average value up to -10 W m-2). Direct heat input is found negligible, thus the net temperature effect is also negative over land (-0.5 K). Nevertheless, positive temperature changes are found overseas (hourly value up to +2 K), due to the amplified radiation absorption by aged soot, coupled to the intense stabilization of the atmosphere above the sea surface.

  17. Investigation of seasonal dynamics of β- and γ-radiation Helds vertical profile in the surface atmospheric layer

    NASA Astrophysics Data System (ADS)

    Ryabkina, K. S.; Kondratyeva, A. G.; Nagorskiy, P. M.; Yakovleva, V. S.

    2016-06-01

    This paper is devoted to the seasonal dynamics of β- and γ-radiation field vertical profile in the surface atmospheric layer study. The findings revealed the following: a) significant seasonal variation in vertical distribution characteristics fields β- and γ-radiation b) reduced β-radiation flux density and γ-radiation dose with increasing height is maintained in the range of spring and fall, namely, starting with snow melt and finishing its setting; c) distortion vertical profile in the winter season, an inverse relationship β-flux density and dose rate of γ-radiation from the heights above the earth's surface was registered.

  18. Atmospheric parameters affecting sea ice losses in the context of gravity desalination

    NASA Astrophysics Data System (ADS)

    Li, Ying; Gu, Wei; Chao, Jinlong; Li, Lantao; Liu, Chengyu; Xu, Yinjun; Chang, Zhiyun; Wu, Linhong; Chen, Jie

    2015-08-01

    Gravity desalination is an important method for obtaining fresh water from sea ice; however, the large amount of ice that is exposed to air for long periods of time sublimates and evaporates, which results in a reduction of the freshwater resource. This paper describes a study of sea ice sublimation and evaporation performed during the winter of 2013 at the western shore of Bohai Bay, China, to determine the relationship between the amount of sublimation and evaporation and the atmospheric parameters. Substantial amounts of the Bohai sea ice sublimated and evaporated, ranging from 15 to 35 % of the total. The sublimation and evaporation amount was significantly different between the day and night and was greater in the daytime because of the relative humidity difference. Sublimation and evaporation is primarily affected by atmospheric parameters, and the amount of sublimation and evaporation exhibits a good linear relationship with the relative humidity and the wind speed; a comprehensive parameters formula was determined for the Bohai Rim in China. A 10 % increase of daily relative humidity will reduce approximately 1.5 kg/m2/day of the sublimation and evaporation, and the amount of sublimation and evaporation increases by 1.76 kg/m2/day when the daily wind speed increases by 1 m/s. To reduce the sublimation and evaporation and maximize the amount of this freshwater resource, gravity desalination sites should be selected where the wind speed is low and the relative humidity is high, i.e., the sea ice should be configured to reduce the adverse effects of sunlight, low humidity, and air turbulence.

  19. Is UV-B radiation affecting charophycean algae in shallow freshwater systems?

    PubMed

    de Bakker, Nancy V J; van Bodegom, P M; van de Poll, W H; Boelen, P; Nat, E; Rozema, J; Aerts, R

    2005-06-01

    The objective of this study was to determine the effects of UV-B radiation on charophycean algae under natural conditions, since charophytes enhance water transparency in freshwater systems and levels of UV-B radiation have increased by ozone depletion. Potential and actual UV-B effects were studied by combining a glasshouse experiment in which plants were exposed to various levels of UV-B radiation and field measurements in two freshwater systems dominated by charophytes in the Netherlands. The glasshouse experiment showed that charophytes were sensitive to UV-B radiation. UV-B radiation negatively affected growth, while it increased levels of DNA damage in Chara aspera. Moreover, the charophytes did not seem to develop UV-B screens to protect against UV-B radiation since no increase in UV-B absorbing compounds was found. At field conditions, both spectroradiometrical measurements and DNA dosimeters showed that UV-B radiation was attenuated quickly in both freshwater systems, indicating that UV-B does not reach the submerged charophyte vegetation. However, specific conditions, like fluctuating water tables, may result in UV-B exposure to charophytes for certain periods annually.

  20. Radiative ion-ion neutralization: a new gas-phase atmospheric pressure ion transduction mechanism.

    PubMed

    Davis, Eric J; Siems, William F; Hill, Herbert H

    2012-06-01

    All atmospheric pressure ion detectors, including photo ionization detectors, flame ionization detectors, electron capture detectors, and ion mobility spectrometers, utilize Faraday plate designs in which ionic charge is collected and amplified. The sensitivity of these Faraday plate ion detectors are limited by thermal (Johnson) noise in the associated electronics. Thus approximately 10(6) ions per second are required for a minimal detection. This is not the case for ion detection under vacuum conditions where secondary electron multipliers (SEMs) can be used. SEMs produce a cascade of approximately 10(6) electrons per ion impinging on the conversion dynode. Similarly, photomultiplier tubes (PMTs) can generate approximately 10(6) electrons per photon. Unlike SEMs, however, PMTs are evacuated and sealed so that they are commonly used under atmospheric pressure conditions. This paper describes an atmospheric pressure ion detector based on coupling a PMT with light emitted from ion-ion neutralization reactions. The normal Faraday plate collector electrode was replaced with an electrode "needle" used to concentrate the anions as they were drawn to the tip of the needle by a strong focusing electric field. Light was emitted near the surface of the electrode when analyte ions were neutralized with cations produced from the anode. Although radiative-ion-ion recombination has been previously reported, this is the first time ions from separate ionization sources have been combined to produce light. The light from this radiative-ion-ion-neutralization (RIIN) was detected using a photon multiplier such that an ion mobility spectrum was obtained by monitoring the light emitted from mobility separated ions. An IMS spectrum of nitroglycerin (NG) was obtained utilizing RIIN for tranducing the mobility separated ions into an analytical signal. The implications of this novel ion transduction method are the potential for counting ions at atmospheric pressure and for obtaining ion

  1. Seasonal variation of surface and atmospheric cloud radiative forcing over the globe derived from satellite data

    NASA Technical Reports Server (NTRS)

    Gupta, Shashi K.; Staylor, W. Frank; Darnell, Wayne L.; Wilber, Anne C.; Ritchey, Nancy A.

    1993-01-01

    Global distributions of surface and atmospheric cloud radiative forcing parameters have been derived using parameterized radiation models with satellite meteorological data from the International Satellite Cloud Climatology Project, and directly measured top-of-atmosphere radiative fluxes from the Earth Radiation Budget Experiment. Specifically, shortwave, longwave, and total cloud forcing at the surface, and column-averaged values of longwave cloud forcing of the atmosphere were derived for the midseasonal months of April, July, and October 1985 and January 1986, covering a complete annual cycle. Seasonal variability is illustrated by comparing the results for July 1985 and January 1986, which represent the seasonal extremes. Surface shortwave cloud forcing is always negative, representing a cooling of the surface, with strongest cooling (-120 to -180 W/sq m) occurring over midlatitude storm tracks of the summer hemisphere. Surface longwave cloud forcing is always positive, representing a warming of the surface, with strongest warming (60 to 75 W/sq m) occurring over storm tracks of the winter hemisphere. Zonal averages show the entire summer hemisphere dominated by shortwave cooling, the middle and high latitudes of the winter hemisphere dominated by longwave warming, and a broad zone of transition in between. The globally averaged total cloud forcing amounts to a cooling throughout the year, ranging from a low of about -12 W/sq m for July 1985 to a high of about -25 W/sq m for January 1986. The longwave cloud forcing of the atmosphere shows a strong warming over deep convective regions in the tropics and a moderate cooling outside the tropics, amounting to a weak cooling (-2 to -5 W/sq m) in the global average. Comparisons of the results with general circulation model simulations show broad qualitative agreement regarding the locations of prominent warming and cooling regions. Quantitative comparisons, on the other hand, show significant differences between the

  2. A TIME-DEPENDENT RADIATIVE MODEL FOR THE ATMOSPHERE OF THE ECCENTRIC EXOPLANETS

    SciTech Connect

    Iro, N.; Deming, L. D. E-mail: leo.d.deming@nasa.go

    2010-03-20

    We present a time-dependent radiative model for the atmosphere of extrasolar planets that takes into account the eccentricity of their orbit. In addition to the modulation of stellar irradiation by the varying planet-star distance, the pseudo-synchronous rotation of the planets may play a significant role. We include both of these time-dependent effects when modeling the planetary thermal structure. We investigate the thermal structure and spectral characteristics for time-dependent stellar heating for two highly eccentric planets. Finally, we discuss observational aspects for those planets suitable for Spitzer measurements and investigate the role of the rotation rate.

  3. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report October 1–December 31, 2012

    SciTech Connect

    Voyles, JW

    2013-01-11

    Individual datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile research sites are collected and routed to the Data Management Facility (DMF) for processing in near-real-time. Instrument and processed data are then delivered approximately daily to the ARM Data Archive, where they are made freely available to the research community. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Data Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year dating back to 1998.

  4. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report July 1–September 30, 2012

    SciTech Connect

    Voyles, JW

    2012-10-10

    Individual datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile research sites are collected and routed to the Data Management Facility (DMF) for processing in near-real-time. Instrument and processed data are then delivered approximately daily to the ARM Data Archive, where they are made freely available to the research community. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Data Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  5. A Time-Dependent Radiative Model for the Atmosphere of the Eccentric Exoplanets

    NASA Astrophysics Data System (ADS)

    Iro, N.; Deming, L. D.

    2010-03-01

    We present a time-dependent radiative model for the atmosphere of extrasolar planets that takes into account the eccentricity of their orbit. In addition to the modulation of stellar irradiation by the varying planet-star distance, the pseudo-synchronous rotation of the planets may play a significant role. We include both of these time-dependent effects when modeling the planetary thermal structure. We investigate the thermal structure and spectral characteristics for time-dependent stellar heating for two highly eccentric planets. Finally, we discuss observational aspects for those planets suitable for Spitzer measurements and investigate the role of the rotation rate.

  6. Inverse atmospheric radiative transfer problems - A nonlinear minimization search method of solution. [aerosol pollution monitoring

    NASA Technical Reports Server (NTRS)

    Fymat, A. L.

    1976-01-01

    The paper studies the inversion of the radiative transfer equation describing the interaction of electromagnetic radiation with atmospheric aerosols. The interaction can be considered as the propagation in the aerosol medium of two light beams: the direct beam in the line-of-sight attenuated by absorption and scattering, and the diffuse beam arising from scattering into the viewing direction, which propagates more or less in random fashion. The latter beam has single scattering and multiple scattering contributions. In the former case and for single scattering, the problem is reducible to first-kind Fredholm equations, while for multiple scattering it is necessary to invert partial integrodifferential equations. A nonlinear minimization search method, applicable to the solution of both types of problems has been developed, and is applied here to the problem of monitoring aerosol pollution, namely the complex refractive index and size distribution of aerosol particles.

  7. Radiation Exchanges at the Atmosphere-Vegetation Canopy Boundary Layer Based on Unmanned Aerial Vehicle Observations

    NASA Astrophysics Data System (ADS)

    Dim, J. R.; Kajiwara, K.; Honda, Y.

    2007-12-01

    Radiation exchanges at the vegetation boundary layer, regulating the amount of energy received by the vegetation canopy are examined through remote sensing observations carried out by an unmanned helicopter, flying according to pre-programmed plans, above a forested area. Information obtained from the laser scanning system, radiometric measurements and aerial photographs are combined to ambient meteorological parameters in order to examine interactions between leaf characteristics, elements of vegetation structure, and the surrounding atmosphere. A vegetation mass transfer model showing variable dependencies of leaf water content, leaf temperature, leaf-air vapor-pressure differences and solar radiation intensity as well as canopy structure is used to discuss transpiration mechanisms of the studied forest.

  8. On the magnetic field signal radiated by an atmospheric pressure room temperature plasma jet

    SciTech Connect

    Wu, S.; Huang, Q.; Wang, Z.; Lu, X.

    2013-01-28

    In this paper, the magnetic field signal radiated from an atmospheric pressure room temperature plasma plume is measured. It's found that the magnetic field signal has similar waveform as the current carried by the plasma plume. By calibration of the magnetic field signal, the plasma plume current is obtained by measuring the magnetic field signal radiated by the plasma plume. In addition, it is found that, when gas flow modes changes from laminar regime to turbulence regime, the magnetic field signal waveforms appears different, it changes from a smooth curve to a curve with multiple spikes. Furthermore, it is confirmed that the plasma plume generated by a single electrode (without ground electrode) plasma jet device carries higher current than that with ground electrode.

  9. Large-Scale Modes of a Nonrotating Atmosphere with Water Vapor and Cloud-Radiation Feedbacks.

    NASA Astrophysics Data System (ADS)

    Fuchs, Eljka; Raymond, David J.

    2002-05-01

    A minimal model of a moist equatorial atmosphere is presented in which the precipitation rate is assumed to depend on just the vertically averaged saturation deficit and the convective available potential energy. When wind-induced surface heat exchange (WISHE) and cloud-radiation interactions are turned off, there are no growing modes. Gravity waves with wavenumbers smaller than a certain limit respond to a reduced static stability due to latent heat release, and therefore propagate more slowly than dry modes, while those with larger wavenumbers respond to the normal dry static stability. In addition, there exists a stationary mode that decays slowly with time. For realistic parameter values, the effect of reduced static stability on gravity waves is limited to wavelengths greater than the circumference of the earth. WISHE and cloud-radiation interactions both destabilize the stationary mode, but not the gravity waves.

  10. Electron density and temperature measurement by continuum radiation emitted from weakly ionized atmospheric pressure plasmas

    SciTech Connect

    Park, Sanghoo; Choe, Wonho; Youn Moon, Se; Park, Jaeyoung

    2014-02-24

    The electron-atom neutral bremsstrahlung continuum radiation emitted from weakly ionized plasmas is investigated for electron density and temperature diagnostics. The continuum spectrum in 450–1000 nm emitted from the argon atmospheric pressure plasma is found to be in excellent agreement with the neutral bremsstrahlung formula with the electron-atom momentum transfer cross-section given by Popović. In 280–450 nm, however, a large discrepancy between the measured and the neutral bremsstrahlung emissivities is observed. We find that without accounting for the radiative H{sub 2} dissociation continuum, the temperature, and density measurements would be largely wrong, so that it should be taken into account for accurate measurement.

  11. Multi-Decadal Variations of Atmospheric Aerosols and Their Effects on Surface Radiation Trends

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Wild, Martin; Qian, Yun; Yu, Hongbin; Streets, David; Bian, Huisheng; Wang, Weiguo

    2010-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007, during which a suite of aerosol data from satellite observations, ground-based measurements, and intensive field experiments have become available. We analyze the long-term global and regional aerosol trends and their relationship to the changes of aerosol and precursor emissions and assess the role aerosols play in the multi-decadal change of solar radiation reaching the surface (known as "dimming" or "brightening") at different regions of the world.

  12. Atmospheric Radiation Measurement Program Science Plan. Current Status and Future Directions of the ARM Science Program

    SciTech Connect

    Ackerman, Thomas P.; Del Genio, Anthony D.; Ellingson, Robert G.; Ferrare, Richard A.; Klein, Steve A.; McFarquhar, Gregory M.; Lamb, Peter J.; Long, Charles M.; Verlinde, Johannes

    2004-10-30

    The Atmospheric Radiation Measurement (ARM) Program has matured into one of the key programs in the U.S. Climate Change Science Program. The ARM Program has achieved considerable scientific success in a broad range of activities, including site and instrument development, atmospheric radiative transfer, aerosol science, determination of cloud properties, cloud modeling, and cloud parameterization testing and development. The focus of ARM science has naturally shifted during the last few years to an increasing emphasis on modeling and parameterization studies to take advantage of the long time series of data now available. During the next 5 years, the principal focus of the ARM science program will be to: Maintain the data record at the fixed ARM sites for at least the next five years; Improve significantly our understanding of and ability to parameterize the 3-D cloud-radiation problem at scales from the local atmospheric column to the global climate model (GCM) grid square; Continue developing techniques to retrieve the properties of all clouds, with a special focus on ice clouds and mixed-phase clouds; Develop a focused research effort on the indirect aerosol problem that spans observations, physical models, and climate model parameterizations; Implement and evaluate an operational methodology to calculate broad-band heating rates in the atmospheric columns at the ARM sites; Develop and implement methodologies to use ARM data more effectively to test atmospheric models, both at the cloud-resolving model scale and the GCM scale; and, Use these methodologies to diagnose cloud parameterization performance and then refine these parameterizations to improve the accuracy of climate model simulations. In addition, the ARM Program is actively developing a new ARM Mobile Facility (AMF) that will be available for short deployments (several months to a year or more) in climatically important regions. The AMF will have much of the same instrumentation as the remote

  13. Infrared radiative transfer in atmospheres of Earth-like planets around F, G, K, and M stars. I. Clear-sky thermal emission spectra and weighting functions

    NASA Astrophysics Data System (ADS)

    Vasquez, M.; Schreier, F.; Gimeno García, S.; Kitzmann, D.; Patzer, B.; Rauer, H.; Trautmann, T.

    2013-01-01

    Context. The atmosphere of Earth-like extrasolar planets orbiting different types of stars is influenced by the spectral dependence of the incoming stellar radiation. The changes in structure and composition affect atmospheric radiation, hence the spectral appearance of these exoplanets. Aims: We provide a thorough investigation of infrared radiative transfer in cloud-free exoplanets atmospheres by not only analyzing the planetary spectral appearance but also discussing the radiative processes behind the spectral features in detail and identifying the regions in the atmosphere that contribute most at a given wavelength. Methods: Using cloud-free scenarios provided by a one-dimensional radiative-convective steady-state atmospheric model, we computed high-resolution infrared transmission and emission spectra, as well as weighting functions for exoplanets located within the habitable zone of F, G, K, and M stars by means of a line-by-line molecular absorption model and a Schwarzschild solver for the radiative transfer. The monochromatic spectra were convolved with appropriate spectral response functions to study the effects of finite instrument resolution. Results: Spectra of the exoplanets of F, G, K, and M stars were analyzed in the 4.5 μm N2O band, the 4.3 μm and 15 μm CO2 bands, the 7.7 μm CH4 band, the 6.3 μm H2O band, and the 9.6 μm O3 band. Differences in the state of the atmosphere of the exoplanets clearly show up in the thermal infrared spectra; absorption signatures known from Earth can be transformed to emission features (and vice versa). Weighting functions show that radiation in the absorption bands of the uniformly mixed gases (CO2, CH4, N2O) and (to some extent) ozone comes from the stratosphere and upper troposphere, and also indicate that changes in the atmospheres can shift sources of thermal radiation to lower or higher altitudes. Molecular absorption and/or emission features can be identified in the high-resolution spectra of all planets and

  14. Global climate modeling of Saturn’s atmosphere. Part I: Evaluation of the radiative transfer model

    NASA Astrophysics Data System (ADS)

    Guerlet, S.; Spiga, A.; Sylvestre, M.; Indurain, M.; Fouchet, T.; Leconte, J.; Millour, E.; Wordsworth, R.; Capderou, M.; Bézard, B.; Forget, F.

    2014-08-01

    We have developed and optimized a seasonal, radiative-convective model of Saturn’s upper troposphere and stratosphere. It is used to investigate Saturn’s radiatively-forced thermal structure between 3 and 10-6 bar, and is intended to be included in a Saturn global climate model (GCM), currently under development. The main elements of the radiative transfer model are detailed as well as the sensitivity to spectroscopic parameters, hydrocarbon abundances, aerosol properties, oblateness, and ring shadowing effects. The vertical temperature structure and meridional seasonal contrasts obtained by the model are then compared to Cassini/CIRS observations. Several significant model-observation mismatches reveal that Saturn’s atmosphere departs from radiative equilibrium. For instance, we find that the modeled temperature profile is close to isothermal above the 2-mbar level, while the temperature retrieved from ground-based or Cassini/CIRS data continues to increase with altitude. Also, no local temperature minimum associated to the ring shadowing is observed in the data, while the model predicts stratospheric temperatures 10 K to 20 K cooler than in the absence of rings at winter tropical latitudes. These anomalies are strong evidence that processes other that radiative heating and cooling control Saturn’s stratospheric thermal structure. Finally, the model is used to study the warm stratospheric anomaly triggered after the 2010 Great White Spot. Comparison with recent Cassini/CIRS observations suggests that the rapid cooling phase of this warm “beacon” in May-June 2011 can be explained by radiative processes alone. Observations on a longer timeline are needed to better characterize and understand its long-term evolution.

  15. Bayesian Atmospheric Radiative Transfer (BART): Model, Statistics Driver, and Application to HD 209458b

    NASA Astrophysics Data System (ADS)

    Cubillos, Patricio; Harrington, Joseph; Blecic, Jasmina; Stemm, Madison M.; Lust, Nate B.; Foster, Andrew S.; Rojo, Patricio M.; Loredo, Thomas J.

    2014-11-01

    Multi-wavelength secondary-eclipse and transit depths probe the thermo-chemical properties of exoplanets. In recent years, several research groups have developed retrieval codes to analyze the existing data and study the prospects of future facilities. However, the scientific community has limited access to these packages. Here we premiere the open-source Bayesian Atmospheric Radiative Transfer (BART) code. We discuss the key aspects of the radiative-transfer algorithm and the statistical package. The radiation code includes line databases for all HITRAN molecules, high-temperature H2O, TiO, and VO, and includes a preprocessor for adding additional line databases without recompiling the radiation code. Collision-induced absorption lines are available for H2-H2 and H2-He. The parameterized thermal and molecular abundance profiles can be modified arbitrarily without recompilation. The generated spectra are integrated over arbitrary bandpasses for comparison to data. BART's statistical package, Multi-core Markov-chain Monte Carlo (MC3), is a general-purpose MCMC module. MC3 implements the Differental-evolution Markov-chain Monte Carlo algorithm (ter Braak 2006, 2009). MC3 converges 20-400 times faster than the usual Metropolis-Hastings MCMC algorithm, and in addition uses the Message Passing Interface (MPI) to parallelize the MCMC chains. We apply the BART retrieval code to the HD 209458b data set to estimate the planet's temperature profile and molecular abundances. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

  16. Comparison of polarized radiative transfer programs with applications to atmospheric and oceanic physics

    NASA Astrophysics Data System (ADS)

    Cohen, Dennis

    We first introduce the topic of radiative transfer and how it applies to a range of problems in physics from remote sensing of the Earth's atmospheres and oceans to investigating skin cancer. We then review the theoretical basis for radiative transfer modeling, which is further supplemented by Appendices 1-3. Afterwards a comparison is presented of two different methods for polarized radiative transfer in coupled media consisting of two adjacent slabs with different refractive indices, each slab being a stratified medium with no change in optical properties except in the direction of stratification. One of the methods is based on solving the integro-differential radiative transfer equation for the two coupled slabs using the discrete ordinate approximation. The other method is based on probabilistic and statistical concepts and simulates the propagation of polarized light using the Monte Carlo approach. The emphasis is on non-Rayleigh scattering for particles in the Mie regime. Comparisons with benchmark results available for a slab with constant refractive index show that both methods reproduce these benchmark results when the refractive index is set to be the same in the two slabs. We then we present a simple study to investigate the sensitivity of the Stokes components I, Q, and U to changes in a bimodal aerosol model for atmosphere-ocean scenes. Preliminary results show that there is significant promise in using the Q Stokes parameter in addition to I, while for this case U is deemed to be insensitive to our simple aerosol model. Lastly we conclude the work completed and suggest possible avenues for future work.

  17. Shortwave Radiative Closure Studies for Clear Skies During the Atmospheric Radiation Measurement 2003 Aerosol Intensive Observation Period

    SciTech Connect

    Michalsky, Joseph J.; Anderson, Gail; Barnard, James C.; Delamere, Jennifer; Gueymard, C.; Kato, Seiji; Kiedron, P.; McComiskey, A.; Ricchiazzi, P.

    2006-07-20

    The Department of Energy's Atmospheric Radiation Measurement (ARM) program sponsored a large aerosol intensive observation period (AIOP) to study aerosol during the month of May 2003 around the Southern Great Plains (SGP) Climate Research Facility (CRF) in north central Oklahoma. Redundant measurements of aerosol optical properties were made using different techniques at the surface as well as in vertical profile with sensors aboard two aircraft. One of the principal motivations for this experiment was to resolve the disagreement between models and measurements of diffuse horizontal broadband shortwave irradiance at the surface, especially for modest aerosol loading. This paper focuses on using the redundant aerosol and radiation measurements during this AIOP to compare direct beam and diffuse horizontal broadband shortwave irradiance measurements and models at the surface for a wide range of aerosol cases that occurred during 30 clear-sky periods on 13 days of May 2003. Models and measurements are compared over a large range of solar-zenith angles. Six different models are used to assess the relative agreement among them and the measurements. Better agreement than previously achieved appears to be the result of better specification of input parameters and better measurements of irradiances than in prior studies. Biases between modeled and measured direct irradiances are in the worst case 1%, and biases between modeled and measured diffuse irradiances are less than 1.9%.

  18. Preliminary results on soil-emitted gamma radiation and its relation with the local atmospheric electric field at Amieira (Portugal)

    NASA Astrophysics Data System (ADS)

    Lopes, F.; Silva, H. G.; Bárias, S.; Barbosa, S. M.

    2015-10-01

    The atmospheric electric field near the Earth's surface is dominated by atmospheric pollutants and natural radioactivity, with the latter directly linked to radon (222Rn) gas. For a better comprehension on the temporal variability of both the atmospheric electric field and the radon concentration and its relation with local atmospheric variables, simultaneous measurements of soil-emitted gamma radiation and potential gradient (defined from the vertical component of the atmospheric electric field) were taken every minute, along with local meteorological parameters (e.g., temperature, atmospheric pressure, relative humidity and daily solar radiation). The study region is Amieira, part of the Alqueva lake in Alentejo Portugal, where an interdisciplinary meteorological campaign, ALEX2014, took place from June to August 2014. Soil gamma radiation is more sensitive to small concentrations of radon as compared with alpha particles measurements, for that reason it is more suited for sites with low radon levels, as expected in this case. Preliminary results are presented here: statistical and spectral analysis show that i) the potential gradient has a stronger daily cycle as compared with the gamma radiation, ii) most of the energy of the gamma signal is concentrated in the low frequencies (close to 0), contrary to the potential gradient that has most of the energy in frequency 1 (daily cycle) and iii) a short-term relation between gamma radiation and the potential gradient has not been found. Future work and plans are also discussed.

  19. Assessing 1D Atmospheric Solar Radiative Transfer Models: Interpretation and Handling of Unresolved Clouds.

    NASA Astrophysics Data System (ADS)

    Barker, H. W.; Stephens, G. L.; Partain, P. T.; Bergman, J. W.; Bonnel, B.; Campana, K.; Clothiaux, E. E.; Clough, S.; Cusack, S.; Delamere, J.; Edwards, J.; Evans, K. F.; Fouquart, Y.; Freidenreich, S.; Galin, V.; Hou, Y.; Kato, S.; Li, J.;  Mlawer, E.;  Morcrette, J.-J.;  O'Hirok, W.;  Räisänen, P.;  Ramaswamy, V.;  Ritter, B.;  Rozanov, E.;  Schlesinger, M.;  Shibata, K.;  Sporyshev, P.;  Sun, Z.;  Wendisch, M.;  Wood, N.;  Yang, F.

    2003-08-01

    The primary purpose of this study is to assess the performance of 1D solar radiative transfer codes that are used currently both for research and in weather and climate models. Emphasis is on interpretation and handling of unresolved clouds. Answers are sought to the following questions: (i) How well do 1D solar codes interpret and handle columns of information pertaining to partly cloudy atmospheres? (ii) Regardless of the adequacy of their assumptions about unresolved clouds, do 1D solar codes perform as intended?One clear-sky and two plane-parallel, homogeneous (PPH) overcast cloud cases serve to elucidate 1D model differences due to varying treatments of gaseous transmittances, cloud optical properties, and basic radiative transfer. The remaining four cases involve 3D distributions of cloud water and water vapor as simulated by cloud-resolving models. Results for 25 1D codes, which included two line-by-line (LBL) models (clear and overcast only) and four 3D Monte Carlo (MC) photon transport algorithms, were submitted by 22 groups. Benchmark, domain-averaged irradiance profiles were computed by the MC codes. For the clear and overcast cases, all MC estimates of top-of-atmosphere albedo, atmospheric absorptance, and surface absorptance agree with one of the LBL codes to within ±2%. Most 1D codes underestimate atmospheric absorptance by typically 15-25 W m-2 at overhead sun for the standard tropical atmosphere regardless of clouds.Depending on assumptions about unresolved clouds, the 1D codes were partitioned into four genres: (i) horizontal variability, (ii) exact overlap of PPH clouds, (iii) maximum/random overlap of PPH clouds, and (iv) random overlap of PPH clouds. A single MC code was used to establish conditional benchmarks applicable to each genre, and all MC codes were used to establish the full 3D benchmarks. There is a tendency for 1D codes to cluster near their respective conditional benchmarks, though intragenre variances typically exceed those for

  20. Influence of higher atmospheric pressure on the Martian radiation environment: Implications for possible habitability in the Noachian epoch

    NASA Astrophysics Data System (ADS)

    Ehresmann, B.; Burmeister, S.; Wimmer-Schweingruber, R. F.; Reitz, G.

    2011-10-01

    The Noachian epoch (˜4.5-3.5 billion years ago) is a promising era for a possible emergence of life on Mars. The presence of runoff channels in areas formed during the Noachian suggests that liquid water existed at least sporadically during that time, with liquid water being regarded as a prerequisite for life. To have sustained liquid water, the atmospheric pressure on Noachian Mars must have been significantly higher than in the present. When considering the possibility of life on Noachian Mars, one conceivable restriction is given by the ionising radiation environment. Using PLANETOCOSMICS- and Geant4-simulation codes, we calculate the radiation environment on the Martian surface and the resulting radiation exposure for different atmospheric conditions. Here, we present absorbed dose and dose equivalent rates resulting from galactic-cosmic-proton and alpha-particle-induced radiation environments, as well as changes of these rates caused by an increase of atmospheric pressure.

  1. Results of a comprehensive atmospheric aerosol-radiation experiment in the southwestern United States. I - Size distribution, extinction optical depth and vertical profiles of aerosols suspended in the atmosphere. II - Radiation flux measurements and

    NASA Technical Reports Server (NTRS)

    Deluisi, J. J.; Furukawa, F. M.; Gillette, D. A.; Schuster, B. G.; Charlson, R. J.; Porch, W. M.; Fegley, R. W.; Herman, B. M.; Rabinoff, R. A.; Twitty, J. T.

    1976-01-01

    Results are reported for a field test that was aimed at acquiring a sufficient set of measurements of aerosol properties required as input for radiative-transfer calculations relevant to the earth's radiation balance. These measurements include aerosol extinction and size distributions, vertical profiles of aerosols, and radiation fluxes. Physically consistent, vertically inhomogeneous models of the aerosol characteristics of a turbid atmosphere over a desert and an agricultural region are constructed by using direct and indirect sampling techniques. These results are applied for a theoretical interpretation of airborne radiation-flux measurements. The absorption term of the complex refractive index of aerosols is estimated, a regional variation in the refractive index is noted, and the magnitude of solar-radiation absorption by aerosols and atmospheric molecules is determined.

  2. Local and regional factors affecting atmospheric mercury speciation at a remote location

    USGS Publications Warehouse

    Manolopoulos, H.; Schauer, J.J.; Purcell, M.D.; Rudolph, T.M.; Olson, M.L.; Rodger, B.; Krabbenhoft, D.P.

    2007-01-01

    Atmospheric concentrations of elemental (Hg0), reactive gaseous (RGM), and particulate (PHg) mercury were measured at two remote sites in the midwestern United States. Concurrent measurements of Hg0, PHg, and RGM obtained at Devil's Lake and Mt. Horeb, located approximately 65 km apart, showed that Hg0 and PHg concentrations were affected by regional, as well as local sources, while RGM was mainly impacted by local sources. Plumes reaching the Devil's Lake site from a nearby coal-fired power plant significantly impacted SO2 and RGM concentrations at Devil's Lake, but had little impact on Hg0. Our findings suggest that traditional modeling approaches to assess sources of mercury deposited that utilize source emissions and large-scale grids may not be sufficient to predict mercury deposition at sensitive locations due to the importance of small-scale sources and processes. We suggest the use of a receptor-based monitoring to better understand mercury source-receptor relationships. ?? 2007 NRC Canada.

  3. Study of the atmospheric conditions affecting infrared astronomical measurements at White Mountain, California

    NASA Technical Reports Server (NTRS)

    Field, G. B.

    1974-01-01

    Measurements are described of atmospheric conditions affecting astronomical observations at White Mountain, California. Measurements were made at more than 1400 times spaced over more than 170 days at the Summit Laboratory and a small number of days at the Barcroft Laboratory. The recorded quantities were ten micron sky noise and precipitable water vapor, plus wet and dry bulb temperatures, wind speed and direction, brightness of the sky near the sun, fisheye lens photographs of the sky, description of cloud cover and other observable parameters, color photographs of air pollution astronomical seeing, and occasional determinations of the visible light brightness of the night sky. Measurements of some of these parameters have been made for over twenty years at the Barcroft and Crooked Creek Laboratories, and statistical analyses were made of them. These results and interpretations are given. The bulk of the collected data are statistically analyzed, and disposition of the detailed data is described. Most of the data are available in machine readable form. A detailed discussion of the techniques proposed for operation at White Mountain is given, showing how to cope with the mountain and climatic problems.

  4. Easy Aerosol - Robust and non-robust circulation responses to aerosol radiative forcing in comprehensive atmosphere models

    NASA Astrophysics Data System (ADS)

    Voigt, Aiko; Bony, Sandrine; Stevens, Bjorn; Boucher, Olivier; Medeiros, Brian; Pincus, Robert; Wang, Zhili; Zhang, Kai; Lewinschal, Anna; Bellouin, Nicolas; Yang, Young-Min

    2015-04-01

    A number of recent studies illustrated the potential of aerosols to change the large-scale atmospheric circulation and precipitation patterns. It remains unclear, however, to what extent the proposed aerosol-induced changes reflect robust model behavior or are affected by uncertainties in the models' treatment of parametrized physical processes, such as those related to clouds. "Easy Aerosol", a model-intercomparison project organized within the Grand Challenge on Clouds, Circulation and Climate Sensitivity of the World Climate Research Programme, addresses this question by subjecting a suite of comprehensive atmosphere general circulation models with prescribed sea-surface temperatures (SSTs) to the same set of idealized "easy" aerosol perturbations. This contribution discusses the aerosol perturbations as well as their impact on the model's precipitation and surface winds. The aerosol perturbations are designed based on a global aerosol climatology and mimic the gravest mode of the anthropogenic aerosol. Specifically, the meridional and zonal distributions of total aerosol optical depth are approximated by a superposition of Gaussian plumes; the vertical distribution is taken as constant within the lowest 1250m of the atmosphere followed by an exponential decay with height above. The aerosol both scatters and absorbs shortwave radiation, but in order to focus on direct radiative effects aerosol-cloud interactions are omitted. Each model contributes seven simulations. A clean control case with no aerosol-radiative effects at all is compared to six perturbed simulations with differing aerosol loading, zonal aerosol distributions, and SSTs. To estimate the role of natural variability, one of the models, MPI-ESM, contributes a 5-member ensemble for each simulation. If the observed SSTs from years 1979-2005 are prescribed, the aerosol leads to a local depression of precipitation at the Northern Hemisphere center of the aerosol and a northward shift of the

  5. Atmospheric propagation of high power laser radiation at different weather conditions

    NASA Astrophysics Data System (ADS)

    Pargmann, Carsten; Hall, Thomas; Duschek, Frank; Handke, Jürgen

    2016-05-01

    Applications based on the propagation of high power laser radiation through the atmosphere are limited in range and effect, due to weather dependent beam wandering, beam deterioration, and scattering processes. Security and defense related application examples are countermeasures against hostile projectiles and the powering of satellites and aircrafts. For an examination of the correlations between weather condition and laser beam characteristics DLR operates at Lampoldshausen a 130 m long free transmission laser test range. Sensors around this test range continuously monitor turbulence strength, visibility, precipitation, temperature, and wind speed. High power laser radiation is obtained by a TruDisk 6001 disk laser (Trumpf company) yielding a maximum output power of 6 kW at a wavelength of 1030 nm. The laser beam is expanded to 180 mm and focused along the beam path. Power and intensity distribution are measured before and after propagation, providing information about the atmospheric transmission and alterations of diameter and position of the laser beam. Backscattered laser light is acquired by a photo receiver. As a result, measurements performed at different weather conditions show a couple of correlations to the characteristics of the laser beam. The experimental results are compared to a numerical analysis. The calculations are based on the Maxwell wave equation in Fresnel approximation. The turbulence is considered by the introduction of phase screens and the "von Karman" spectrum.

  6. A new dynamical atmospheric ionizing radiation (AIR) model for epidemiological studies

    NASA Technical Reports Server (NTRS)

    De Angelis, G.; Clem, J. M.; Goldhagen, P. E.; Wilson, J. W.

    2003-01-01

    A new Atmospheric Ionizing Radiation (AIR) model is currently being developed for use in radiation dose evaluation in epidemiological studies targeted to atmospheric flight personnel such as civilian airlines crewmembers. The model will allow computing values for biologically relevant parameters, e.g. dose equivalent and effective dose, for individual flights from 1945. Each flight is described by its actual three dimensional flight profile, i.e. geographic coordinates and altitudes varying with time. Solar modulated primary particles are filtered with a new analytical fully angular dependent geomagnetic cut off rigidity model, as a function of latitude, longitude, arrival direction, altitude and time. The particle transport results have been obtained with a technique based on the three-dimensional Monte Carlo transport code FLUKA, with a special procedure to deal with HZE particles. Particle fluxes are transformed into dose-related quantities and then integrated all along the flight path to obtain the overall flight dose. Preliminary validations of the particle transport technique using data from the AIR Project ER-2 flight campaign of measurements are encouraging. Future efforts will deal with modeling of the effects of the aircraft structure as well as inclusion of solar particle events. Published by Elsevier Ltd on behalf of COSPAR.

  7. Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large predatory fish.

    PubMed

    Dahl, Tais W; Hammarlund, Emma U; Anbar, Ariel D; Bond, David P G; Gill, Benjamin C; Gordon, Gwyneth W; Knoll, Andrew H; Nielsen, Arne T; Schovsbo, Niels H; Canfield, Donald E

    2010-10-19

    The evolution of Earth's biota is intimately linked to the oxygenation of the oceans and atmosphere. We use the isotopic composition and concentration of molybdenum (Mo) in sedimentary rocks to explore this relationship. Our results indicate two episodes of global ocean oxygenation. The first coincides with the emergence of the Ediacaran fauna, including large, motile bilaterian animals, ca. 550-560 million year ago (Ma), reinforcing previous geochemical indications that Earth surface oxygenation facilitated this radiation. The second, perhaps larger, oxygenation took place around 400 Ma, well after the initial rise of animals and, therefore, suggesting that early metazoans evolved in a relatively low oxygen environment. This later oxygenation correlates with the diversification of vascular plants, which likely contributed to increased oxygenation through the enhanced burial of organic carbon in sediments. It also correlates with a pronounced radiation of large predatory fish, animals with high oxygen demand. We thereby couple the redox history of the atmosphere and oceans to major events in animal evolution. PMID:20884852

  8. Windowless transition between atmospheric pressure and high vacuum via differential pumping for synchrotron radiation applications.

    PubMed

    Gog, T; Casa, D M; Kuzmenko, I; Krakora, R J; Bolin, T B

    2007-07-01

    A differential pump assembly is introduced which can provide a windowless transition between the full atmospheric pressure of an in-air sample environment and the high-vacuum region of a synchrotron radiation beamline, while providing a clear aperture of approximately 1 mm to pass through the X-ray beam from a modern third-generation synchrotron radiation source. This novel pump assembly is meant to be used as a substitute for an exit vacuum window on synchrotron beamlines, where the existence of such a window would negatively impact the coherent nature of the X-ray beam or would introduce parasitic scattering, distorting weak scattering signals from samples under study. It is found that the length of beam pipe necessary to reduce atmospheric pressure to below 10 mbar is only about 130 mm, making the expected photon transmission for hard X-rays through this pipe competitive with that of a regular Be beamline window. This result is due to turbulent flow dominating the first pumping stage, providing a mechanism of strong gas conductance limitation, which is further enhanced by introducing artificial surface roughness in the pipe. Successive reduction of pressure through the transitional flow regime into the high-vacuum region is accomplished over a length of several meters, using beam pipes of increasing diameter. While the pump assembly has not been tested with X-rays, possible applications are discussed in the context of coherent and small-angle scattering. PMID:17587659

  9. A model for inactivation of microbes suspended in the atmosphere by solar ultraviolet radiation.

    PubMed

    Ben-David, Avishai; Sagripanti, Jose-Luis

    2010-01-01

    Solar ultraviolet (UV) light within 280-320 nm (UVB) is the primary cause for virus inactivation in the atmosphere. Only the effect of the direct component has been previously evaluated. We developed a simple regression model to estimate the inactivation of a virus due to direct (unscattered), diffuse (scattered) and total (direct + diffuse) components of solar UV (daily integrated irradiances). The model predicts the maximum number of radiation-days a virus will survive at a given altitude above the ground in rural and urban environments under clear skies. We explored the effect of several environmental variables: visibility, altitude and ground reflectivity. We found that the effect of diffuse radiation on virus inactivation was larger than the direct component. The diffuse irradiance increased with ground albedo (mainly due to reflection of the direct attenuated solar off the ground) and decreased with increased visibility (proportional to aerosol loading in the atmosphere). The diffuse component increased with altitude, but the ratio of diffuse to the total decreased with increased altitude, highlighting the importance of the diffuse component of UV near the ground. Our model may help public health studies in predicting and understanding the effect of environmental parameters on the survival of germs.

  10. Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large predatory fish

    PubMed Central

    Dahl, Tais W.; Hammarlund, Emma U.; Anbar, Ariel D.; Bond, David P. G.; Gill, Benjamin C.; Gordon, Gwyneth W.; Knoll, Andrew H.; Nielsen, Arne T.; Schovsbo, Niels H.; Canfield, Donald E.

    2010-01-01

    The evolution of Earth’s biota is intimately linked to the oxygenation of the oceans and atmosphere. We use the isotopic composition and concentration of molybdenum (Mo) in sedimentary rocks to explore this relationship. Our results indicate two episodes of global ocean oxygenation. The first coincides with the emergence of the Ediacaran fauna, including large, motile bilaterian animals, ca. 550–560 million year ago (Ma), reinforcing previous geochemical indications that Earth surface oxygenation facilitated this radiation. The second, perhaps larger, oxygenation took place around 400 Ma, well after the initial rise of animals and, therefore, suggesting that early metazoans evolved in a relatively low oxygen environment. This later oxygenation correlates with the diversification of vascular plants, which likely contributed to increased oxygenation through the enhanced burial of organic carbon in sediments. It also correlates with a pronounced radiation of large predatory fish, animals with high oxygen demand. We thereby couple the redox history of the atmosphere and oceans to major events in animal evolution. PMID:20884852

  11. Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large predatory fish.

    PubMed

    Dahl, Tais W; Hammarlund, Emma U; Anbar, Ariel D; Bond, David P G; Gill, Benjamin C; Gordon, Gwyneth W; Knoll, Andrew H; Nielsen, Arne T; Schovsbo, Niels H; Canfield, Donald E

    2010-10-19

    The evolution of Earth's biota is intimately linked to the oxygenation of the oceans and atmosphere. We use the isotopic composition and concentration of molybdenum (Mo) in sedimentary rocks to explore this relationship. Our results indicate two episodes of global ocean oxygenation. The first coincides with the emergence of the Ediacaran fauna, including large, motile bilaterian animals, ca. 550-560 million year ago (Ma), reinforcing previous geochemical indications that Earth surface oxygenation facilitated this radiation. The second, perhaps larger, oxygenation took place around 400 Ma, well after the initial rise of animals and, therefore, suggesting that early metazoans evolved in a relatively low oxygen environment. This later oxygenation correlates with the diversification of vascular plants, which likely contributed to increased oxygenation through the enhanced burial of organic carbon in sediments. It also correlates with a pronounced radiation of large predatory fish, animals with high oxygen demand. We thereby couple the redox history of the atmosphere and oceans to major events in animal evolution.

  12. Our contaminated atmosphere: The danger of climate change, phases 1 and 2. [effect of atmospheric particulate matter on surface temperature and earth's radiation budget

    NASA Technical Reports Server (NTRS)

    Cimorelli, A. J.; House, F. B.

    1974-01-01

    The effects of increased concentrations of atmospheric particulate matter on average surface temperature and on the components of the earth's radiation budget are studied. An atmospheric model which couples particulate loading to surface temperature and to changes in the earth's radiation budget was used. A determination of the feasibility of using satellites to monitor the effect of increased atmospheric particulate concentrations is performed. It was found that: (1) a change in man-made particulate loading of a factor of 4 is sufficient to initiate an ice age; (2) variations in the global and hemispheric weighted averages of surface temperature, reflected radiant fluz and emitted radiant flux are nonlinear functions of particulate loading; and (3) a black satellite sphere meets the requirement of night time measurement sensitivity, but not the required day time sensitivity. A nonblack, spherical radiometer whose external optical properties are sensitive to either the reflected radiant fluz or the emitted radiant flux meets the observational sensitivity requirements.

  13. An analysis of the dependence of clear-sky top-of-atmosphere outgoing longwave radiation on atmospheric temperature and water vapor

    NASA Astrophysics Data System (ADS)

    Dessler, A. E.; Yang, P.; Lee, J.; Solbrig, J.; Zhang, Z.; Minschwaner, K.

    2008-09-01

    We have analyzed observations of clear-sky top-of-atmosphere outgoing longwave radiation (OLR) measured by the Clouds and the Earth's Radiant Energy System (CERES). These measurements were obtained during March 2005 at night and over the ocean and cover latitudes from 70°N to 70°S. First, we compare the OLR measurements to OLR calculated from two radiative transfer models. The models use as input simultaneous and collocated measurements of atmospheric temperature and atmospheric water vapor made by the Atmospheric Infrared Sounder (AIRS). We find excellent agreement between the models' predictions of OLR and observations, well within the uncertainty of the measurements. We also analyze the sensitivity of OLR to changing surface temperature Ts, atmospheric temperature Ta, and atmospheric water vapor q. We find that OLR is most sensitive to unit changes in Ta when that change occurs in the lower troposphere. For q, the altitude distribution of sensitivity varies between the midlatitudes, subtropics, and the convective region. We also partition the observed variations in OLR into contributions from changing Ts, Ta, and q. In the midlatitudes, changes in Ts and Ta contribute approximately equally, and are partially offset by changes in q. In the subtropics, changes in Ta dominate, with a smaller contribution from changes in Ts and a relatively small offsetting contribution from q. In the tropical convective region, a rapid increase in q in the midtroposphere leads to a dramatic reduction in OLR with increasing Ts, which has been termed the "super greenhouse effect".

  14. Radiation dose rates in Space Shuttle as a function of atmospheric density.

    PubMed

    Badhwar, G D

    1999-06-01

    Current models of the inner trapped belt describe the radiation environment at times of solar minimum and solar maximum, respectively. These two models were constructed using data acquired prior to 1970 during a small solar cycle, and no valid model for the past two high solar cycles exists. There is a clear need to accurately predict the radiation exposure of astronauts at all times between the solar minimum and solar maximum, not only on the short duration Space Shuttle flights, but on the longer term stay onboard the Mir orbital station and the planned International Space Station (ISS). An analysis of the trapped absorbed dose rate, D, at six fixed locations in the habitable volume of the Shuttle shows a power law relationship, D=A rho-n, where rho is the atmospheric density, rho. The index, n, is weakly dependent on the shielding, decreasing as the average shielding increases. A better representation is provided by D=A tan-1 [(Xi-Xi c)/(Xi c-Xi m)], where Xi=ln(rho), and A, Xi c, and Xi m are constants. Xi c is related to the atmospheric density near the altitude of atmospheric cutoff. These relationships hold over nearly four decades of density variation and throughout the solar cycle. This then provides a method of calculating absorbed dose rate at anytime in the solar cycle. These empirically derived relations were used to predict the dose rates for eleven Space Shuttle flights carried out since January 1997. The predictions are in excellent agreement with measured values. This method reduces the uncertainties of a factor of about 2 for the AP-8 MIN/MAX models to less than 30%.

  15. WASP-12b According to the Bayesian Atmospheric Radiative Transfer (BART) Code

    NASA Astrophysics Data System (ADS)

    Harrington, Joseph; Cubillos, Patricio E.; Blecic, Jasmina; Challener, Ryan C.; Rojo, Patricio M.; Lust, Nate B.; Bowman, M. Oliver; Blumenthal, Sarah D.; Foster, Andrew SD; Foster, A. J.

    2015-11-01

    We present the Bayesian Atmospheric Radiative Transfer (BART) code for atmospheric property retrievals from transit and eclipse spectra, and apply it to WASP-12b, a hot (~3000 K) exoplanet with a high eclipse signal-to-noise ratio. WASP-12b has been controversial. We (Madhusudhan et al. 2011, Nature) claimed it was the first planet with a high C/O abundance ratio. Line et al. (2014, ApJ) suggested a high CO2 abundance to explain the data. Stevenson et al. (2014, ApJ, atmospheric model by Madhusudhan) add additional data and reaffirm the original result, stating that C2H2 and HCN, not included in the Line et al. models, explain the data. We explore several modeling configurations and include Hubble, Spitzer, and ground-based eclipse data.BART consists of a differential-evolution Markov-Chain Monte Carlo sampler that drives a line-by-line radiative transfer code through the phase space of thermal- and abundance-profile parameters. BART is written in Python and C. Python modules generate atmospheric profiles from sets of MCMC parameters and integrate the resulting spectra over observational bandpasses, allowing high flexibility in modeling the planet without interacting with the fast, C portions that calculate the spectra. BART's shared memory and optimized opacity calculation allow it to run on a laptop, enabling classroom use. Runs can scale constant abundance profiles, profiles of thermochemical equilibrium abundances (TEA) calculated by the included TEA code, or arbitrary curves. Several thermal profile parameterizations are available. BART is an open-source, reproducible-research code. Users must release any code or data modifications if they publish results from it, and we encourage the community to use it and to participate in its development via http://github.com/ExOSPORTS/BART.This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. J. Blecic holds a NASA Earth and Space Science

  16. Research concerning the net flux of radiation in the atmosphere of Jupiter

    NASA Technical Reports Server (NTRS)

    Tomasko, M. G.

    1996-01-01

    The plan of the NFR (Net Flux of Radiation) team is for the data from the two solar channels (B and E) of NFR to be reduced with the goal of determining the solar heating rate. In order to determine the solar heating rate from the NFR measurements, effects due to the instrument's spatial and spectral response functions, to the temperature variation of the instrument (and associated drift of calibration), to the setting sun, and to the rotation of the probe (initially at a rate comparable to the NFR sampling frequency), all must be well modelled. In the past year, a forward modeling routine was created to simulate NFR data return in the B and E channels. The effects of varying parameters describing the atmospheric model (such as cloud location and thickness) and the descent profile (such as rotation rate) were investigated and an inversion routine was developed. For the forward modeling, existing radiative transfer codes were used to determine intensity fields within the Jovian atmosphere. A routine was developed to determine instantaneous instrument response by integrating the intensity field over the instrument response functions. A second routine was developed to determine the actual output of the NFR by integrating along an arbitrary descent trajectory. Near the top of the atmosphere, the upflux data alone are used to constrain the cloud structure of he atmosphere. To accomplish this, models are used to describe the variation in up flux between consecutive measurements in terms of variations of cloud opacity and variations in known parameters such as the solar zenith angle. This allows us to develop a zero-order model of cloud structure. Lower in the atmosphere, at levels where there is little or no azimuthal structure to the net flux measurements, both the up flux and net flux are used to derive layer transmission and reflection functions, which then determine layer opacity and single scattering albedo. A preliminary analysis of the data began in December 1995

  17. A Random Walk on WASP-12b with the Bayesian Atmospheric Radiative Transfer (BART) Code

    NASA Astrophysics Data System (ADS)

    Harrington, Joseph; Cubillos, Patricio; Blecic, Jasmina; Challener, Ryan; Rojo, Patricio; Lust, Nathaniel B.; Bowman, Oliver; Blumenthal, Sarah D.; Foster, Andrew S. D.; Foster, Austin James; Stemm, Madison; Bruce, Dylan

    2016-01-01

    We present the Bayesian Atmospheric Radiative Transfer (BART) code for atmospheric property retrievals from transit and eclipse spectra, and apply it to WASP-12b, a hot (~3000 K) exoplanet with a high eclipse signal-to-noise ratio. WASP-12b has been controversial. We (Madhusudhan et al. 2011, Nature) claimed it was the first planet with a high C/O abundance ratio. Line et al. (2014, ApJ) suggested a high CO2 abundance to explain the data. Stevenson et al. (2014, ApJ, atmospheric model by Madhusudhan) add additional data and reaffirm the original result, stating that C2H2 and HCN, not included in the Line et al. models, explain the data. We explore several modeling configurations and include Hubble, Spitzer, and ground-based eclipse data.BART consists of a differential-evolution Markov-Chain Monte Carlo sampler that drives a line-by-line radiative transfer code through the phase space of thermal- and abundance-profile parameters. BART is written in Python and C. Python modules generate atmospheric profiles from sets of MCMC parameters and integrate the resulting spectra over observational bandpasses, allowing high flexibility in modeling the planet without interacting with the fast, C portions that calculate the spectra. BART's shared memory and optimized opacity calculation allow it to run on a laptop, enabling classroom use. Runs can scale constant abundance profiles, profiles of thermochemical equilibrium abundances (TEA) calculated by the included TEA code, or arbitrary curves. Several thermal profile parameterizations are available. BART is an open-source, reproducible-research code. Users must release any code or data modifications if they publish results from it, and we encourage the community to use it and to participate in its development via http://github.com/ExOSPORTS/BART.This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. J. Blecic holds a NASA Earth and Space Science

  18. Radiance, polarization, and ellipticity of the radiation in the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Hitzfelder, S. J.; Plass, G. N.; Kattawar, G. W.

    1976-01-01

    The complete radiation field including polarization is calculated for a model of the real atmosphere by the matrix operator method. The radiance, direction and amount of polarization, and ellipticity are obtained at the top and bottom of the atmosphere for three values of the surface albedo (0; 0.15 0.90) and five solar zenith angles. Scattering and absorption by molecules (including ozone) and by aerosols are taken into account together with the variation of the number density of these substances with height. All results are calculated for both a normal aerosol number and a distribution which is one-third of the normal amount at all heights. The calculated values show general qualitative agreement with the available experimental measurements. The position of the neutral points of the polarization in the principal plane is a sensitive indicator of the characteristics of the aerosol particles in the atmosphere, since it depends on the sign and value of the single scattered polarization for scattering angles around 20 deg and 160 deg for transmitted and reflected photons respectively.

  19. Solar radiation has a lethal effect on natural populations of culturable outdoor atmospheric bacteria

    NASA Astrophysics Data System (ADS)

    Tong, Yongyi; Lighthart, Bruce

    Ambient heterogenic atmospheric bacteria were collected by impaction directly onto nutrient agar surfaces on clear sunny and cloudy days and at night. Samples were then exposed to summer noontime solar radiation (SR) for increasing periods of time. Bacterial survival was the least for the organisms collected at nighttime and the greatest for those collected during clear sunny days. This result may be due to the inactivation of SR-sensitive bacterial populations by the ambient SR on clear days, and to a lesser extent on cloudy days, leaving only the relatively resistant populations. This does not occur at night when the SR-sensitive populations have not been reduced. The mixed bacterial species populations in the atmosphere do not appear to follow the Bunsen-Roscoe reciprocity law but integration of pure bacterial components of the mixed population that do follow the law, could explain the findings. The populations collected in this investigation exhibited SR survival functions usable in developing survival and dispersion models of outdoor atmospheric bacteria and microbial pesticides.

  20. Development of PARMA: PHITS-based analytical radiation model in the atmosphere.

    PubMed

    Sato, Tatsuhiko; Yasuda, Hiroshi; Niita, Koji; Endo, Akira; Sihver, Lembit

    2008-08-01

    Estimation of cosmic-ray spectra in the atmosphere has been essential for the evaluation of aviation doses. We therefore calculated these spectra by performing Monte Carlo simulation of cosmic-ray propagation in the atmosphere using the PHITS code. The accuracy of the simulation was well verified by experimental data taken under various conditions, even near sea level. Based on a comprehensive analysis of the simulation results, we proposed an analytical model for estimating the cosmic-ray spectra of neutrons, protons, helium ions, muons, electrons, positrons and photons applicable to any location in the atmosphere at altitudes below 20 km. Our model, named PARMA, enables us to calculate the cosmic radiation doses rapidly with a precision equivalent to that of the Monte Carlo simulation, which requires much more computational time. With these properties, PARMA is capable of improving the accuracy and efficiency of the cosmic-ray exposure dose estimations not only for aircrews but also for the public on the ground. PMID:18666812

  1. Processes affecting oxygen isotope ratios of atmospheric and ecosystem sulfate in two contrasting forest catchments in Central Europe

    SciTech Connect

    Martin Novak; Myron J. Mitchell; Iva Jackova; Frantisek Buzek; Jana Schweigstillova; Lucie Erbanova; Richard Prikryl; Daniela Fottova

    2007-02-15

    Sulfate aerosols are harmful as respirable particles. They also play a role as cloud condensation nuclei and have radiative effects on global climate. A combination of {delta}{sup 18}O-SO{sub 4} data with catchment sulfur mass balances was used to constrain processes affecting S cycling in the atmosphere and spruce forests of the Czech Republic. Extremely high S fluxes via spruce throughfall and runoff were measured at Jezeri (49 and 80 kg S ha{sup -1} yr{sup -1}, respectively). The second catchment, Na Lizu, was 10 times less polluted. In both catchments, {delta}{sup 18}O-SO{sub 4} decreased in the following order: open-area precipitation {gt} throughfall {gt} runoff. The 180-SO{sub 4} values of throughfall exhibited a seasonal pattern at both sites, with maxima in summer and minima in winter. This seasonal pattern paralleled {delta}{sup 18}O-H{sub 2}O values, which were offset by -18{per_thousand}. Sulfate in throughfall was predominantly formed by heterogeneous (aqueous) oxidation of SO{sub 2}. Wet-deposited sulfate in an open area did not show systematic {delta}{sup 18}O-SO{sub 4} trends, suggesting formation by homogeneous (gaseous) oxidation and/or transport from large distances. The percentage of incoming S that is organically cycled in soil was similar under the high and the low pollution. High-temperature {sup 18}O-rich sulfate was not detected, which contrasts with North American industrial sites. 29 refs., 4 figs., 3 tabs.

  2. Atmospheric Radiation Measurement (ARM) Data from the Southern Great Plains (SGP) Site

    DOE Data Explorer

    The Atmospheric Radiation Measurement (ARM) Program is the largest global change research program supported by the U.S. Department of Energy. The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. To achieve this goal, ARM scientists and researchers around the world use continuous data obtained through the ARM Climate Research Facility. ARM maintains four major, permanent sites for data collection and deploys the ARM Mobile Facility to other sites as determined. Scientists are using the information obtained from the permanent SGP site to improve cloud and radiative models and parameterizations and, thereby, the performance of atmospheric general circulation models used for climate research. More than 30 instrument clusters have been placed around the SGP site. The locations for the instruments were chosen so that the measurements reflect conditions over the typical distribution of land uses within the site. The continuous observations at the SGP site are supplemented by intensive observation periods, when the frequency of measurements is increased and special measurements are added to address specific research questions. During such periods, 2 gigabytes or more of data (two billion bytes) are generated daily. SGP data sets from 1993 to the present reside in the ARM Archive at http://www.archive.arm.gov/ http. Users will need to register for a password, but all files are then free for viewing or downloading. The ARM Archive physically resides at the Oak Ridge National Laboratory.

  3. Data systems for science integration within the Atmospheric Radiation Measurement Program

    SciTech Connect

    Gracio, D.K.; Hatfield, L.D.; Yates, K.R.; Voyles, J.W.; Tichler, J.L.; Cederwall, R.T.; Laufersweiler, M.J.; Leach, M.J.; Singley, P.

    1995-12-31

    The Atmospheric Radiation Measurement (ARM) Program was developed by the US Department of Energy to support the goals and mission of the US Global Change Research Program. The purpose of the ARM program is to improve the predictive capabilities of General Circulation Models (GCMs) in their treatment of clouds and radiative transfer effects. Three experimental testbeds were designed for the deployment of instruments to collect atmospheric data used to drive the GCMs. Each site, known as a Cloud and Radiation Testbed (CART), consists of a highly available, redundant data system for the collection of data from a variety of instrumentation. The first CART site was deployed in April 1992 in the Southern Great Plains (SGP), Lamont, Oklahoma, with the other two sites to follow in early 1996 in the Tropical Western Pacific (TWP) and in 1997 on the North Slope of Alaska (NSA). Approximately 1.5 GB of data are transferred per day via the Internet from the CART sites, and external data sources to the ARM Experiment Center (EC) at Pacific Northwest Laboratory in Richland, Washington. The Experimental Center is central to the ARM data path and provides for the collection, processing, analysis and delivery of ARM data. Data from the CART sites from a variety of instrumentation, observational systems and from external data sources are transferred to the Experiment Center. The EC processes these data streams on a continuous basis to provide derived data products to the ARM Science Team in near real-time while maintaining a three-month running archive of data.

  4. Effect of the ionizing radiation on the rain-time atmospheric electric field

    NASA Astrophysics Data System (ADS)

    Yamauchi, Masatoshi; Takeda, Masahiko; Makino, Masahiko; Owada, Takeshi

    2013-04-01

    The atmospheric electric field, or potential gradient (PG) at Kakioka, 150 southwest of the Fukushima Nuclear Power Plant (NPP) shows peculiar behaviors after the accident, March 2012 due to the conductivity enhancement in the air by the ionizing radiation. This means that the PG provides significant information on the dynamics of the radioactive materials. During last EGU assembly 2012, we showed that the fine-weather PG decreased by one-two orders of magnitudes at the arrival of the radioactive plume, and that the PG recovered in various way depending on various types of re-suspension processes in addition to the physical decay of the deposited radioactive materials. We extended this work to the rain-time PG, which is very simple because of high variability of the PG depending on the cloud types and distribution. We yet found a statistical difference between rain-time PGs before and after the Fukushima NPP Accident: one-hour averaged rain-time PG during the first 45 days after the accident is not as much scattered to the negative side as those during the same period of different years or during 40 days before accident. Further examination of one-minute averaged data (1 Hz sampling) during the second half March for 2006-2012 revealed that this difference comes from short time-spans of negative peaks rather than the peak value after the accident compared to those before the accident. On the other hand, characteristics of positive peaks (cloud without rain) are unchanged. The results suggest either (1) the effect on the local charges in the rain cloud is narrowed under high dose of ionized radiation, making positive charges in the cloud less shielded by the negative charges, or (2) negative charge of ionized aerosol decays much faster under higher dose of ionized radiation due to the shortened time constant of the ionized aerosol (? 1-?, where ? is the atmospheric electric conductivity).

  5. Intercomparison of spectral irradiance measurements and provision of alternative radiation scheme for CCMs of middle atmosphere

    NASA Astrophysics Data System (ADS)

    Pagaran, Joseph; Weber, Mark; Burrows, John P.

    The Sun's radiative output (total solar irradiance or TSI) determines the thermal structure of the Earth's atmosphere. Its variability is a strong function of wavelength, which drives the photochemistry and general circulation. Contributions to TSI variability from UV wavelengths below 400 nm, i.e. 0.227-day solar rotation or 0.1to be in the 40-60three decades of UV and about a decade of vis-IR observations. Significant progress in UV/vis-IR regions has been achieved with daily monitoring from SCIAMACHY aboard Envisat (ESA) in 2002 and by SIM aboard SORCE (NASA) about a year after. In this contribution, we intercompare SSI measurements from SCIAMACHY and SIM and RGB filters of SPM/VIRGO SoHO: same (a) day and (b) few 27-day time series of spectral measurements in both irradiance and integrated irradiance over selected wavelength intervals. Finally, we show how SSI measurements from GOME, SOLSTICE, in addition to SCIAMACHY and SIM, can be modeled together with solar proxies F10.7 cm, Mg II and sunspot index (PSI) to derive daily SSI variability in the period 1947-2008. The derived variabilities are currently being used as solar input to Bremen's 3D-CTM and are to be recommended as extended alternative to Berlin's FUBRaD radiation scheme. This proxy-based radiation scheme are compared with SATIRE, NRLSSI (or Lean et al.), SUSIM, SSAI (or DeLand et al), and SIP (or Solar2000) models. The use of realistic spectrally resolved solar input to CCMs is to better understand the effects of solar variability on chemistry and temperature in the middle atmosphere over several decades.

  6. A Review of 3D Radiative Transfer in Atmospheric Science: History and Outlook

    NASA Astrophysics Data System (ADS)

    Wiscombe, W. J.

    2006-12-01

    3D radiative transfer has, until recently, remained a marginal subject within atmospheric science. While some measurement techniques like lidar and radar are inherently 3D, the simplifying assumptions made in the use of such data have alleviated any need to deal with 3D radiative transfer. Cloud scenes are obviously 3D, but the crude resolution of past atmospheric models (GCMs) required clouds to be treated as 1D. Measured radiative fluxes containing 3D cloud effects were simply time-averaged until all their 3D-ness was apparently beaten out of them. The main subject which has propelled 3D radiative transfer onto center stage is, nevertheless, clouds. This is because conventional GCMs are being challenged by GCMs that have their large-scale parametrizations of cloud-related processes replaced by explicit cloud-system-resolving models. Within these new GCMs, 3D radiative transfer cannot be ignored since cloud fluctuations are resolved explicitly down to scales where 1D and 3D radiative transfer can differ markedly. This talk will attempt to identify the high points in the development of the 3D cloud radiation field. My own career interleaved with much of this history, including the strong move away from just using computers and toward field observations, and also the effort to fit the new knowledge into climate models. The 3D cloud radiation field began in the 1970s, but attracted few adherents because of severe limitations on computer time and memory, and also because of ignorance of cloud structure (beyond the qualitative classifications which had ruled for 170 years). The earliest landmarks were Monte Carlo calcuations for cubic clouds, whose main point was the drastic errors incurred by ignoring cloud 3D-ness. This line of development ramified until the early 1990s, leading finally to randomly placed cubes with sizes drawn from a probability distribution. A parallel line of development began with the landmark paper of Lovejoy in 1982, which showed that cloud

  7. [Effect of the atmospheric ozone layer on the biologically active ultraviolet radiation on the earth's surface].

    PubMed

    Schulze, R; Kasten, F

    1975-08-01

    Based on measurements of the spectral irradiation intensity of UV-B global radiation by Bener (1960) and on the curve of spectral skin erythema effects newly measured by Urbach and Berger (1972), the biologically active UV-radiation at earth's surface has been calculated as a function of sun's altitude and atmospheric ozone content in so-called "Biological Units": BE = mWh cm-2 times erythema efficacy. On the basis of these data, the total daily, monthly, and yearly amounts of biologically active UV-radiation have been determined for the different geographical latitudes and various ozone contents. Approximately two thirds of BU hit the equatorial zone from 35 degrees south to 35 degrees north. Provided that the stratospheric ozone layer would be reduced by ten per cent from the exhaust gases of supersonic planes flying at high-altitude, an increase of BU would result amounting to 18% at the equator, to 19% in middle latitudes, and to 22% at the poles.

  8. Radiative transfer in the earth's atmosphere and ocean: influence of ocean waves.

    PubMed

    Plass, G N; Kattawar, G W; Guinn, J A

    1975-08-01

    The radiance in the earth's atmosphere and ocean is calculated for a realistic model including an ocean surface with waves. Individual photons are followed in a Monte Carlo calculation. In the atmosphere, both Rayleigh scattering by the molecules and Mie scattering by the aerosols as well as molecular and aerosol absorption are taken into account. Similarly, in the ocean, both Rayleigh scattering by the water molecules and Mie scattering by the hydrosols as well as absorption by the water molecules and hydrosols are considered. Separate single-scattering functions are used which are calculated separately for the aerosols and the hydrosols from the Mie theory with appropriate and different size distributions in each case. The scattering angles are determined from the appropriate scattering function including the strong forwardscattering peak when there is aerosol or hydrosol scattering. Both the reflected and refracted rays, as well as the rays that undergo total internal reflection, are followed at the oceanc surface. The wave slope is chosen from the Cox-Munk distribution. Graphs show the influence of the waves on the upward radiance at the top of the atmosphere and just above the ocean surface and on the downward radiance just below the ocean surface as well as deeper within the ocean. The radiance changes are sufficient at the top of the atmosphere to determine the sea state from satellite measurements. Within the ocean the waves smooth out the abrupt transition that occurs at the edge of the allowed cone for radiation entering a calm ocean. The influence of the waves on the contrast between the sky and sea at the horizon is discussed. It is shown that the downward flux just below the surface increases with wind speed at all solar angles.

  9. Impact of Atmospheric Attenuations Time Resolutions in Solar Radiation Derived from Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Cony, Marco; Liria, Juan; Weisenberg, Ralf; Serrano, Enrique

    2014-05-01

    Accurate knowledge of solar irradiance components at the earth surface is of highly interest in many scientific and technology branches concerning meteorology, climate, agriculture and solar energy applications. In the specific case of solar energy systems the solar resource analysis with accuracy is a first step in every project since it is a required data for design, power output estimations, systems simulations and risk assessments. Solar radiation measurement availability is increasing both in spatial density and in historical archiving. However, it is still quite limited and most of the situations cannot make use of a long term ground database of high quality since solar irradiance is not generally measured where users need data. Satellite-derived solar radiation estimations are a powerful and valuable tool for solar resource assessment studies that have achieved a relatively high maturity due to years of developments and improvements. However, several sources of uncertainty are still present in satellite-derived methods. In particular, the strong influence of atmospheric attenuation information as input to the method is one of the main topics of improvement. Since solar radiation attenuation by atmospheric aerosols, and water vapor in a second place, is, after clouds, the second most important factor determining solar radiation, and particularly direct normal irradiance, the accurate knowledge of aerosol optical depth and water vapor content is relevant in the final output of satellite-derived methods. This present work, two different datasets we are used for extract atmospheric attenuation information. On the one hand the monthly mean values of the Linke turbidity factor from Meteotest database, which are twelve unique values of the Linke turbidity worldwide with a spatial resolution of 1/12º. On the other hand, daily values of AOD (Aerosol Optical Depth) at 550 nm, Angstrom alpha exponent and water vapor column were taken from a gridded database that

  10. Progress and Status on the Development of NASA's Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model

    NASA Astrophysics Data System (ADS)

    Mertens, C. J.; Tobiska, W. K.; Blattnig, S. R.; Kress, B. T.; Wiltberger, M. J.; Solomon, S. C.; Kunches, J.; Murray, J. J.

    2008-12-01

    The NASA Applied Sciences Program recently selected a project for funding through the Research Opportunities in Space and Earth Sciences (ROSES) solicitation. The project objective is to develop a nowcast prediction of air-crew radiation exposure from both background galactic cosmic rays (GCR) and solar energetic particle events (SEP) that may accompany solar storms. The new air-crew radiation exposure model is called the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model. NAIRAS will provide global, data-driven, real-time radiation dose predictions of biologically harmful radiation at commercial airline altitudes. Observations are utilized from the ground (neutron monitors), from the atmosphere (the NCEP reanalysis), and from space (NASA/ACE and NOAA/GOES). Atmospheric observations provide the overhead shielding information and the ground- and space-based observations provide boundary conditions on the incident GCR and SEP particle flux distributions for transport and dosimetry simulations. Dose rates are calculated using the parametric AIR (Atmospheric Ionizing Radiation) model and the physics-based HZETRN (High Charge and Energy Transport) code. In this paper we discuss the concept and design of the NAIRAS model, and present recent progress in the implementation and give examples of the model results. Specifically, we show predictions of representative annual background exposure levels and radiation exposure levels for selected SEP events during solar cycle 23, with emphasis on the high-latitude and polar region. We also characterize the suppression of the geomagnetic cutoff rigidity during these storm periods and their subsequent influence on atmospheric radiation exposure. We discuss the key uncertainties and areas that need improvement in both model and data, the timeline for project completion, and access to model results.

  11. National Survey of Radiation Doses of Pediatric Chest Radiography in Korea: Analysis of the Factors Affecting Radiation Doses

    PubMed Central

    Kim, Bo Hyun; Goo, Hyun Woo; Yang, Dong Hyun; Oh, Sang Young; Kim, Hyeog Ju; Lee, Kwang Yong; Lee, Jung Eun

    2012-01-01

    Objective To investigate radiation doses in pediatric chest radiography in a national survey and to analyze the factors that affect radiation doses. Materials and Methods The study was based on the results of 149 chest radiography machines in 135 hospitals nationwide. For each machine, a chest radiograph was obtained by using a phantom representing a 5-year-old child (ATOM® dosimetry phantom, model 705-D, CIRS, Norfolk, VA, USA) with each hospital's own protocol. Five glass dosimeters (M-GD352M, Asahi Techno Glass Corporation, Shizuoka, Japan) were horizontally installed at the center of the phantom to measure the dose. Other factors including machine's radiography system, presence of dedicated pediatric radiography machine, presence of an attending pediatric radiologist, and the use of automatic exposure control (AEC) were also evaluated. Results The average protocol for pediatric chest radiography examination in Korea was 94.9 peak kilovoltage and 4.30 milliampere second. The mean entrance surface dose (ESD) during a single examination was 140.4 microgray (µGy). The third quartile, median, minimum and maximum value of ESD were 160.8 µGy, 93.4 µGy, 18.8 µGy, and 2334.6 µGy, respectively. There was no significant dose difference between digital and non-digital radiography systems. The use of AEC significantly reduced radiation doses of pediatric chest radiographs (p < 0.001). Conclusion Our nationwide survey shows that the third quartile, median, and mean ESD for pediatric chest radiograph is 160.8 µGy, 93.4 µGy, and 140.4 µGy, respectively. No significant dose difference is noticed between digital and non-digital radiography systems, and the use of AEC helps significantly reduce radiation doses. PMID:22977329

  12. Photochemistry and radiative transfer studies in the atmospheres of Jupiter and Saturn

    NASA Astrophysics Data System (ADS)

    Parkinson, Christopher Dennis

    This work is mainly an amalgam of work done over several years and different topics. There are three main areas of investigation: (a)Saturnian He 584 Å airglow intensity, (b)deuterium chemistry and emission in the Jovian Thermosphere, and (c)Jovian tropospheric deuterated species abundances, viz., CH3D (Parkinson et al., 1998; Parkinson et al., 2002a; and Parkinson et al., 2002a). Calculations of the Saturnian He 584 Å airglow intensity, using radiative transfer models with partial frequency redistribution and inhomogeneous atmospheric models, are presented. For reference conditions and an atmosphere consistent with the Voyager UVS occultation results, we require the eddy diffusion coefficients at the homopause. Kh, to be greater than 109 cm2 s-1 in order to fit the Ultraviolet Spectrometer measurements of Voyager 1 and 2 He 584 Å airglow measurements. These values of Kh seem unreasonably high when compared to the earlier work of Sandel et al. (1982) and Atreya (1982). This suggests that either the values of one or more of the parameters of our model are not correct or that the measured UVS airglow is too bright and that there is a problem with calibration. Even so, we suggest that Kh is likely to be greater than 2 × 107 cm2 s-1 during the period of the Voyager encounters. Jupiter's atmosphere contains proto-solar abundances of H and D, and therefore may be studied in an attempt to derive the solar system D/H value. The solar system D/H problem can be approached in a number of ways: (a)D and H Lyman-α, Lyman-β, (b)CH3D and CH4, and (c)HD and H2 (from ISO/Galileo probe). First suggested by Ben Jaffel (private communication, 1999), this strategy is termed the ‘global approach’. Using this approach and utilising the same atmospheric model should ideally provide the same D/H ratio regardless of the technique used or the location in the atmosphere one is studying. The D/H problem has been extensively modelled utilising the ‘global approach’ and the results

  13. Simulation of the imaging quality of ground-based telescopes affected by atmospheric disturbances

    NASA Astrophysics Data System (ADS)

    Ren, Yubin; Kou, Songfeng; Gu, Bozhong

    2014-08-01

    Ground-based telescope imaging model is developed in this paper, the relationship between the atmospheric disturbances and the ground-based telescope image quality is studied. Simulation of the wave-front distortions caused by atmospheric turbulences has long been an important method in the study of the propagation of light through the atmosphere. The phase of the starlight wave-front is changed over time, but in an appropriate short exposure time, the atmospheric disturbances can be considered as "frozen". In accordance with Kolmogorov turbulence theory, simulating atmospheric disturbances of image model based on the phase screen distorted by atmospheric turbulences is achieved by the fast Fourier transform (FFT). Geiger mode avalanche photodiode array (APD arrays) model is used for atmospheric wave-front detection, the image is achieved by inversion method of photon counting after the target starlight goes through phase screens and ground-based telescopes. Ground-based telescope imaging model is established in this paper can accurately achieve the relationship between the quality of telescope imaging and monolayer or multilayer atmosphere disturbances, and it is great significance for the wave-front detection and optical correction in a Multi-conjugate Adaptive Optics system (MCAO).

  14. Anorectal Cancer: Critical Anatomic and Staging Distinctions That Affect Use of Radiation Therapy.

    PubMed

    Matalon, Shanna A; Mamon, Harvey J; Fuchs, Charles S; Doyle, Leona A; Tirumani, Sree Harsha; Ramaiya, Nikhil H; Rosenthal, Michael H

    2015-01-01

    Although rectal and anal cancers are anatomically close, they are distinct entities with different histologic features, risk factors, staging systems, and treatment pathways. Imaging is at the core of initial clinical staging of these cancers and most commonly includes magnetic resonance imaging for local-regional staging and computed tomography for evaluation of metastatic disease. The details of the primary tumor and involvement of regional lymph nodes are crucial in determining if and how radiation therapy should be used in treatment of these cancers. Unfortunately, available imaging modalities have been shown to have imperfect accuracy for identification of nodal metastases and imaging features other than size. Staging of nonmetastatic rectal cancers is dependent on the depth of invasion (T stage) and the number of involved regional lymph nodes (N stage). Staging of nonmetastatic anal cancers is determined according to the size of the primary mass and the combination of regional nodal sites involved; the number of positive nodes at each site is not a consideration for staging. Patients with T3 rectal tumors and/or involvement of perirectal, mesenteric, and internal iliac lymph nodes receive radiation therapy. Almost all anal cancers warrant use of radiation therapy, but the extent and dose of the radiation fields is altered on the basis of both the size of the primary lesion and the presence and extent of nodal involvement. The radiologist must recognize and report these critical anatomic and staging distinctions, which affect use of radiation therapy in patients with anal and rectal cancers.

  15. Data management and scientific integration within the Atmospheric Radiation Measurement Program

    NASA Technical Reports Server (NTRS)

    Gracio, Deborah K.; Hatfield, Larry D.; Yates, Kenneth R.; Voyles, Jimmy W.; Tichler, Joyce L.; Cederwall, Richard T.; Laufersweiler, Mark J.; Leach, Martin J.; Singley, Paul

    1995-01-01

    The Atmospheric Radiation Measurement (ARM) Program has been developed by the U.S. Department of Energy with the goal to improve the predictive capabilities of General Circulation Models (GCM's) in their treatment of clouds and radiative transfer effects. To achieve this goal, three experimental testbeds were designed for the deployment of instruments that will collect atmospheric data used to drive the GCM's. Each site, known as a Cloud and Radiation Testbed (CART), consists of a highly available, redundant data system for the collection of data from a variety of instrumentation. The first CART site was deployed in April 1992 in the Southern Great Plains (SGP), Lamont, Oklahoma, with the other two sites to follow in September 1995 in the Tropical Western Pacific and in 1997 on the North Slope of Alaska. Approximately 400 MB of data are transferred per day via the Internet from the SGP site to the ARM Experiment Center at Pacific Northwest Laboratory in Richland, Washington. The Experiment Center is central to the ARM data path and provides for the collection, processing, analysis, and delivery of ARM data. Data are received from the CART sites from a variety of instrumentation, observational systems, amd external data sources. The Experiment Center processes these data streams on a continuous basis to provide derived data products to the ARM Science Team in near real-time while providing a three-month running archive of data. A primary requirement of the ARM Program is to preserve and protect all data produced or acquired. This function is performed at Oak Ridge National Laboratory where leading edge technology is employed for the long-term storage of ARM data. The ARM Archive provides access to data for participation outside of the ARM Program. The ARM Program involves a collaborative effort by teams from various DOE National Laboratories, providing multi-disciplinary areas of expertise. This paper will discuss the collaborative methods in which the ARM teams

  16. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    PubMed

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating.

  17. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    PubMed

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. PMID:27344510

  18. Chemical, physical and radiative properties of atmospheric aerosols measured at Mt. Lulin Atmospheric Background Station (LABS) in East Asia during biomass burning seasons (Invited)

    NASA Astrophysics Data System (ADS)

    Lin, N.; Lee, C.; Wang, S.; Chuang, M.; Chia, E.; Andrews, E.; Ogren, J. A.; Lin, J.; Hung, H.; Hsiao, T.; Liang, S.

    2013-12-01

    This paper presents the chemical, physical and radiative properties of atmospheric aerosols measured at the Lulin Atmospheric Background Station (LABS) which is located at Mt. Lulin (2,862 m MSL; 23o 28'07"N, 120o52'25"E) in central Taiwan, East Asia, and has been operated since 13 April, 2006. LABS is unique because its location and altitude enhances the global network of GAW (Global Atmosphere Watch) in the Southeast Asian region, where no high-elevation baseline station is available. Our site is located between the GAW Waliguan station (3,810 m) on the Tibetan plateau and the Mauna Loa Observatory (3,397m) in Hawaii. We will particularly focus on the results obtained during the spring season, when biomass burning activities prevail in northern Southeast Asia. Chemical characterization of fine and coarse aerosol particles, including water-soluble ions, organic and elemental carbon, and trace elements, will be presented. Aerosol optical properties, including scattering, absorption, extinction, single scattering albedo, Ångström exponent, and aerosol optical depth, as well as the derived radiative forcing efficiency, will be discussed. Results of cloud condensation nuclei measurements, made intermittently, will also be presented. Trajectory studies indicate that this site experiences a variety of air masses originating from contaminated and clean source regions, giving a distinctive contrast of atmospheric changes. To summarize the results, the maximum values (and monthly means) of these chemical, physical and radiative parameters generally occurred during spring time, especially in March, corresponding to prevailing biomass burning activities in SE Asia. Besides, LABS is also one of the supersites during the 2010-2013 spring campaigns of the Seven South East Asian Studies (7-SEAS) for studying the impact of biomass burning on cloud, atmospheric radiation, hydrological cycle, and regional climate over Southeast Asian region. Results of source (northern Thailand

  19. Laboratory Kinetic Studies of OH and CO2 Relevant to Upper Atmospheric Radiation Balance

    NASA Technical Reports Server (NTRS)

    Nelson, David D.; Villalta, Peter; Zahniser, Mark S.; Kolb, Charles E.

    1997-01-01

    The purpose of this project was to quantify the rates of two processes which are crucial to our understanding of radiative energy balance in the upper atmosphere. The first process is radiative emission from vibrationally hot OH radicals following the H + O3 reaction in the upper mesosphere. The importance of this process depends strongly on the OH radiative emission coefficients. Our goal was to measure the OH permanent dipole moment in excited vibrational states and to use these measurements to construct an improved OH dipole moment function and improved radiative emission coefficients. Significant progress was made on these experiments including the construction of a supersonic jet source for vibrationally excited OH radicals. Unfortunately, our efforts to transport the OH radicals into a second lower pressure vacuum chamber were not successful, and we were unable to make improved dipole moment measurements for OH. The second key kinetic process which we attempted to quantify during this project is the rate of relaxation of bend-excited CO2 by oxygen atoms. Since excitation of the bending vibrational mode of CO2 is the major cooling mechanism in the upper mesosphere/lower thermosphere, the cooling rate of this region depends crucially on the rate of energy transfer out of this state. It is believed that the most efficient transfer mechanism is via atomic oxygen but the rate for this process has not been directly measured in the laboratory at appropriate temperatures and even the room temperature rate remains controversial. We attempted to directly measure the relaxation rate Of CO2 (010) by oxygen atoms using the discharge flow technique. This experiment was set up at Aerodyne Research. Again, significant progress was achieved in this experiment. A hot CO2 source was set up, bend excited CO2 was detected and the rate of relaxation of bend excited CO2 by He atoms was measured. Unfortunately, the project ran out of time before the oxygen atom kinetic studies could

  20. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2006

    SciTech Connect

    DL Sisterson

    2006-10-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998.

  1. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report January 1–March 31, 2012

    SciTech Connect

    Voyles, JW

    2012-04-13

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Data Archive, where they are made available to the research community. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  2. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - January 1 - March 31, 2008

    SciTech Connect

    Sisterson, DL

    2008-04-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  3. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 – June 30, 2006

    SciTech Connect

    DL Sisterson

    2006-07-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year; and (2) site and fiscal year dating back to 1998.

  4. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2009

    SciTech Connect

    DL Sisterson

    2009-10-15

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data then are sent approximately daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by 1) individual data stream, site, and month for the current year and 2) site and fiscal year (FY) dating back to 1998.

  5. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - July 1 - September 30, 2008

    SciTech Connect

    DL Sisterson

    2008-09-30

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  6. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 - March 31, 2009

    SciTech Connect

    DL Sisterson

    2009-03-17

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  7. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report October 1 - December 31, 2007

    SciTech Connect

    DL Sisterson

    2008-01-08

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  8. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report: October 1 - December 31, 2010

    SciTech Connect

    Sisterson, DL

    2011-03-02

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  9. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report July 1–September 30, 2011

    SciTech Connect

    Voyles, JW

    2011-10-10

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  10. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - October 1 - December 31, 2008

    SciTech Connect

    Sisterson, DL

    2009-01-15

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  11. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 - June 30, 2008

    SciTech Connect

    DL Sisterson

    2008-06-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  12. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 - June 30, 2007

    SciTech Connect

    DL Sisterson

    2007-07-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  13. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 – March 31, 2007

    SciTech Connect

    DL Sisterson

    2007-04-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  14. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report October 1–December 31, 2011

    SciTech Connect

    Voyles, JW

    2012-01-09

    Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  15. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 - September 30, 2007

    SciTech Connect

    DL Sisterson

    2007-10-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  16. Ozonesonde measurements from the Atmospheric Radiation Measurement (ARM) site in Billings, Oklahoma

    SciTech Connect

    1998-12-01

    Ozonesonde instruments were prepared and released at the Atmospheric Radiation Measurement (ARM) site located near Billings, Oklahoma. Ozone sensors, associated radiosondes, balloons, and other parts and pieces required for the ozone observations were provided by WFF on a reimbursable arrangement with ANL. Observations were scheduled daily at 1,700 UTC beginning on September 22, 1995. Attempts to maintain this schedule were frustrated by a few simultaneous operations involving different electronic devices in use resulting in considerable rf noise. Since radiosondes are necessarily low-cost instruments their reception is particularly susceptible to noisy rf fields. Overall, however, 36 ozonesonde flights were made with the last observation occurring on November 1, 1995. Ozone data were processed on-site through the ground-station software and preliminary data delivered to Mike Splitt at the ARM site.

  17. Oxygen at 2 atmospheres absolute pressure does not increase the radiation sensitivity of normal brain in rats

    SciTech Connect

    Routh, A.; Kapp, J.P.; Smith, E.E.; Bebin, J.; Barnes, T.; Hickman, B.T.

    1984-07-01

    Cranial radiation was administered to CD Fisher rats at 1.0, 1.5 and 2.0 atmospheres oxygen pressure. Life span following radiation was recorded. Surviving animals were killed at 28 weeks and the brains were examined independently by two neuropathologists. Survival time was significantly less in animals receiving higher doses of radiation but showed no relationship to the oxygen pressure in the environment of the animal at the time radiation was administered. Microscopic examination of the brain did not reveal any differences in animals radiated in a normobaric or hyperbaric oxygen environment. It is concluded that hyperbaric oxygen does not sensitize the normal brain to the effects of ionizing radiation.

  18. Laser ablation and ionisation by laser plasma radiation in the atmospheric-pressure mass spectrometry of organic compounds

    SciTech Connect

    Pento, A V; Nikiforov, S M; Simanovsky, Ya O; Grechnikov, A A; Alimpiev, S S

    2013-01-31

    A new method was developed for the mass spectrometric analysis of organic and bioorganic compounds, which involves laser ablation with the ionisation of its products by laser-plasma radiation and enables analysing gaseous, liquid, and solid substances at atmospheric pressure without sample preparation. The capabilities of this method were demonstrated by the examples of fast pharmaceutical composition screening, real-time atmosphere composition analysis, and construction of the mass spectrometric images of organic compound distributions in biological materials. (interaction of laser radiation with matter)

  19. Radiative Susceptibility of Cloudy Atmospheres to Droplet Number Perturbations: 2. Global analysis from MODIS

    NASA Technical Reports Server (NTRS)

    Oreopoulos, Lazaros; Platnick, Steven

    2008-01-01

    Global distributions of albedo susceptibility for areas covered by liquid clouds are presented for 4 months in 2005. The susceptibility estimates are based on expanded definitions presented in a companion paper and include relative cloud droplet number concentration (CDNC) changes, perturbations in cloud droplet asymmetry parameter and single-scattering albedo, atmospheric/surface effects, and incorporation of the full solar spectrum. The cloud properties (optical thickness and effective radius) used as input in the susceptibility calculations come from MODIS Terra and Aqua Collection 5 gridded data. Geographical distributions of susceptibility corresponding to absolute ( absolute cloud susceptibility ) and relative ( relative cloud susceptibility ) CDNC changes are markedly different indicating that the detailed nature of the cloud microphysical perturbation is important for determining the radiative forcing associated with the first indirect aerosol effect. However, both types of susceptibility exhibit common characteristics such as significant reductions when perturbations in single-scattering properties are omitted, significant increases when atmospheric absorption and surface albedo effects are ignored, and the tendency to decrease with latitude, to be higher over ocean than over land, and to be statistically similar between the morning and afternoon MODIS overpasses. The satellite-based susceptibility analysis helps elucidate the role of present-day cloud and land surface properties in indirect aerosol forcing responses. Our realistic yet moderate CDNC perturbations yield forcings on the order of 1-2 W/sq m for cloud optical property distributions and land surface spectral albedos observed by MODIS. Since susceptibilities can potentially be computed from model fields, these results have practical application in assessing the reasonableness of model-generated estimates of the aerosol indirect radiative forcing.

  20. The Martian surface radiation environment - Influence of higher atmospheric pressure and surface or sub-surface water

    NASA Astrophysics Data System (ADS)

    Ehresmann, B.; Böhm, E.; Kohler, J.; Martin, C.; Wimmer-Schweingruber, R. F.; Reitz, G.; Hassler, D. M.; Zeitlin, C. J.

    2011-12-01

    The Noachian epoch (~4.5 - 3.5 billion years ago) is a promising era for a possible emergence of life on Mars. The presence of runoff channels in areas formed during the Noachian suggests that liquid water existed at least sporadically during that time, with liquid water being regarded as a prerequisite for life. To have sustained liquid water, the atmospheric pressure on Noachian Mars must have been significantly higher than in the present. When considering the possibility of life on Noachian Mars, one conceivable restriction is given by the ionizing radiation environment. Using PLANETOCOSMICS- and GEANT4-simulation codes, we calculate the radiation environment on the Martian surface and the resulting radiation exposure for different atmospheric conditions. Here, we present absorbed dose rates resulting from galactic-cosmic-proton and alpha-particle-induced radiation environments, as well as changes of these rates caused by an increase of atmospheric pressure. Furthermore, we analyze which influence the presence of liquid surface water or sub-surface water-ice would have on the radiation environment under these different atmospheric conditions.

  1. Toward an Improved Understanding of the Tropical Energy Budget Using TRMM-based Atmospheric Radiative Heating Products

    NASA Astrophysics Data System (ADS)

    L'Ecuyer, T.; McGarragh, G.; Ellis, T.; Stephens, G.; Olson, W.; Grecu, M.; Shie, C.; Jiang, X.; Waliser, D.; Li, J.; Tian, B.

    2008-05-01

    It is widely recognized that clouds and precipitation exert a profound influence on the propagation of radiation through the Earth's atmosphere. In fact, feedbacks between clouds, radiation, and precipitation represent one of the most important unresolved factors inhibiting our ability to predict the consequences of global climate change. Since its launch in late 1997, the Tropical Rainfall Measuring Mission (TRMM) has collected more than a decade of rainfall measurements that now form the gold standard of satellite-based precipitation estimates. Although not as widely advertised, the instruments aboard TRMM are also well-suited to the problem of characterizing the distribution of atmospheric heating in the tropics and a series of algorithms have recently been developed for estimating profiles of radiative and latent heating from these measurements. This presentation will describe a new multi-sensor tropical radiative heating product derived primarily from TRMM observations. Extensive evaluation of the products using a combination of ground and satellite-based observations is used to place the dataset in the context of existing techniques for quantifying atmospheric radiative heating. Highlights of several recent applications of the dataset will be presented that illustrate its utility for observation-based analysis of energy and water cycle variability on seasonal to inter-annual timescales and evaluating the representation of these processes in numerical models. Emphasis will be placed on the problem of understanding the impacts of clouds and precipitation on atmospheric heating on large spatial scales, one of the primary benefits of satellite observations like those provided by TRMM.

  2. Geologic and atmospheric input factors affecting watershed chemistry in upper michigan

    NASA Astrophysics Data System (ADS)

    Rapp, George; Liukkonen, Barbara W.; Allert, James D.; Sorensen, John A.; Glass, Gary E.; Loucks, Orie L.

    1987-10-01

    The relationships between watershed variables and lakewater chemistry were examined for 53 lakes in the Upper Peninsula of Michigan to identify factors influencing lake sensitivity to atmospheric inputs. The lakes lie in three distinct geologic/geomorphic regions. Acid neutralization capacity (ANC), sulfate, and color were correlated with parameters related to atmospheric loading, watershed area and relief, hydrology, geology, and land use for the entire 53-lake set and for lower alkalinity subsets. Acid-neutralizing capacity was related to atmospheric acidic inputs and, in the southern portion of the Upper Peninsula, to the presence of mineralized groundwater inputs. In the north, ANC is correlated with hydrologic lake type and surficial deposits. Results show the highest density of acidified lakes in the northern region, which is underlain by noncalcareous sedimentary rocks. Color was related to lake size and the presence of organic soils in the watershed, whereas lake sulfate concentration was mainly influenced by atmospheric or groundwater inputs, surficial deposits, and soil type.

  3. How much has the increase in atmospheric CO2 directly affected past soybean production?

    NASA Astrophysics Data System (ADS)

    Sakurai, Gen; Iizumi, Toshichika; Nishimori, Motoki; Yokozawa, Masayuki

    2014-05-01

    Understanding the effects of climate change is vital for food security. Among the most important environmental impacts of climate change is the direct effect of increased atmospheric carbon dioxide concentration ([CO2]) on crop yields, known as the CO2 fertilization effect. Although several statistical studies have estimated past impacts of temperature and precipitation on crop yield at regional scales, the impact of past CO2 fertilization is not well known. We evaluated how soybean yields have been enhanced by historical atmospheric [CO2] increases in three major soybean-producing countries. The estimated average yields during 2002-2006 in the USA, Brazil, and China were 4.34%, 7.57%, and 5.10% larger, respectively, than the average yields estimated using the atmospheric [CO2] of 1980. Our results demonstrate the importance of considering atmospheric [CO2] increases in evaluations of the past effects of climate change on crop yields.

  4. How much has the increase in atmospheric CO2 directly affected past soybean production?

    PubMed

    Sakurai, Gen; Iizumi, Toshichika; Nishimori, Motoki; Yokozawa, Masayuki

    2014-05-15

    Understanding the effects of climate change is vital for food security. Among the most important environmental impacts of climate change is the direct effect of increased atmospheric carbon dioxide concentration ([CO2]) on crop yields, known as the CO2 fertilization effect. Although several statistical studies have estimated past impacts of temperature and precipitation on crop yield at regional scales, the impact of past CO2 fertilization is not well known. We evaluated how soybean yields have been enhanced by historical atmospheric [CO2] increases in three major soybean-producing countries. The estimated average yields during 2002-2006 in the USA, Brazil, and China were 4.34%, 7.57%, and 5.10% larger, respectively, than the average yields estimated using the atmospheric [CO2] of 1980. Our results demonstrate the importance of considering atmospheric [CO2] increases in evaluations of the past effects of climate change on crop yields.

  5. How much has the increase in atmospheric CO2 directly affected past soybean production?

    PubMed

    Sakurai, Gen; Iizumi, Toshichika; Nishimori, Motoki; Yokozawa, Masayuki

    2014-01-01

    Understanding the effects of climate change is vital for food security. Among the most important environmental impacts of climate change is the direct effect of increased atmospheric carbon dioxide concentration ([CO2]) on crop yields, known as the CO2 fertilization effect. Although several statistical studies have estimated past impacts of temperature and precipitation on crop yield at regional scales, the impact of past CO2 fertilization is not well known. We evaluated how soybean yields have been enhanced by historical atmospheric [CO2] increases in three major soybean-producing countries. The estimated average yields during 2002-2006 in the USA, Brazil, and China were 4.34%, 7.57%, and 5.10% larger, respectively, than the average yields estimated using the atmospheric [CO2] of 1980. Our results demonstrate the importance of considering atmospheric [CO2] increases in evaluations of the past effects of climate change on crop yields. PMID:24827887

  6. Observed near-surface atmospheric moisture content changes affected by irrigation development in Xinjiang, Northwest China

    NASA Astrophysics Data System (ADS)

    Han, Songjun; Tang, Qiuhong; Xu, Di; Wang, Shaoli; Yang, Zhiyong

    2016-08-01

    The effects of irrigation development on observed near-surface atmospheric moisture changes remain unclear in arid Xinjiang. In this study, cultivated land fractions (CFs) within a 4-km radius of 90 meteorological stations over Xinjiang, which are inferred from the 2000 land use map, are used as a quantitative indicator of irrigation intensity. Trends of observed water vapor pressure and relative humidity during the growing season (May to September) from 1959 to 2006 are significantly positively correlated with CFs of the meteorological stations. Stations with larger CFs experience a more rapid increase in near-surface atmospheric moisture than stations with small CFs. Results indicate that growing season near-surface atmospheric moisture wetting is enhanced by irrigation development for stations with high levels of cultivated land uses. The land use around stations should be considered when analyzing the observed near-surface atmospheric moisture changes in Xinjiang.

  7. Sensitivity of the Tropical Atmosphere Energy Balance to ENSO-Related SST Changes: How Well Can We Quantify Hydrologic and Radiative Responses?

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin R.; Fitzjarrald, Dan; Sohn, Byung-Ju; Arnold, James E. (Technical Monitor)

    2001-01-01

    The continuing debate over feedback mechanisms governing tropical sea surface temperatures (SSTs) and tropical climate in general has highlighted the diversity of potential checks and balances within the climate system. Competing feedbacks due to changes in surface evaporation, water vapor, and cloud long- and shortwave radiative properties each may serve critical roles in stabilizing or destabilizing the climate system. It is also intriguing that even those climate variations having origins internal to the climate system-- changes in ocean heat transport for example, apparently require complementary equilibrating effects by changes in atmospheric energy fluxes. Perhaps the best observational evidence of this is the relatively invariant nature of tropically averaged net radiation exiting the top-of-atmosphere (TOA) as measured by broadband satellite sensors over the past two decades. Thus, analyzing how these feedback mechanisms are operating within the context of current interannual variability may offer considerable insight for anticipating future climate change. In this paper we focus on how fresh water and radiative fluxes over the tropical oceans change during ENSO warm and cold events and how these changes affect the tropical energy balance. At present, ENSO remains the most prominent known mode of natural variability at interannual time scales. Although great advances have been made in understanding this phenomenon and realizing prediction skill over the past decade, our ability to document the coupled water and energy changes observationally and to represent them in climate models seems far from settled (Soden, 2000 J Climate). Our analysis makes use a number of data bases, principally those derived from space-based measurements, to explore systematic changes in rainfall, evaporation, and surface and top-of-atmosphere (TOA) radiative fluxes, A reexamination of the Langley 8-Year Surface Radiation Budget data set reveals errors in the surface longwave

  8. Proceedings of the sixth Atmospheric Radiation Measurement (ARM) Science Team meeting

    SciTech Connect

    1997-06-01

    This document contains the summaries of papers presented at the 1996 Atmospheric Radiation Measurement (ARM) Science Team meeting held at San Antonio, Texas. The history and status of the ARM program at the time of the meeting helps to put these papers in context. The basic themes have not changed. First, from its beginning, the Program has attempted to respond to the most critical scientific issues facing the US Global Change Research Program. Second, the Program has been strongly coupled to other agency and international programs. More specifically, the Program reflects an unprecedented collaboration among agencies of the federal research community, among the US Department of Energy`s (DOE) national laboratories, and between DOE`s research program and related international programs, such as Global Energy and Water Experiment (GEWEX) and the Tropical Ocean Global Atmosphere (TOGA) program. Next, ARM has always attempted to make the most judicious use of its resources by collaborating and leveraging existing assets and has managed to maintain an aggressive schedule despite budgets that have been much smaller than planned. Finally, the Program has attracted some of the very best scientific talent in the climate research community and has, as a result, been productive scientifically.

  9. New high temperature furnace for structure refinement by powder diffraction in controlled atmospheres using synchrotron radiation

    SciTech Connect

    Margulies, L.; Kramer, M.J.; McCallum, R.W.; Kycia, S.; Haeffner, D.R.; Lang, J.C.; Goldman, A.I.

    1999-09-01

    A low thermal gradient furnace design is described which utilizes Debye{endash}Scherrer geometry for performing high temperature x-ray powder diffraction with synchrotron radiation at medium and high energies (35{endash}100 keV). The furnace has a maximum operating temperature of 1800 K with a variety of atmospheres including oxidizing, inert, and reducing. The capability for sample rotation, to ensure powder averaging, has been built into the design without compromising thermal stability or atmosphere control. The ability to perform high-resolution Rietveld refinement on data obtained at high temperatures has been demonstrated, and data collected on standard Al{sub 2}O{sub 3} powder is presented. Time-resolved data on the orthorhombic to rhombohedral solid state phase transformation of SrCO{sub 3} is demonstrated using image plates. Rietveld refinable spectra, collected in as little as 8 s, opens the possibility of performing time-resolved structural refinements of phase transformations. {copyright} {ital 1999 American Institute of Physics.}

  10. Marketability of ready-to-eat cactus pear as affected by temperature and modified atmosphere.

    PubMed

    Cefola, Maria; Renna, Massimiliano; Pace, Bernardo

    2014-01-01

    In order to increase the diffusion of cactus pear fruits, in this study, the proper maturity index for peeling and processing them as ready-to-eat product was evaluated and characterized. Thereafter, the effects of different storage temperatures and modified atmosphere conditions on the marketability of ready-to-eat cactus pear were studied. The storage of ready-to-eat fruits at 4 °C in both passive (air) and semi-active (10 kPa O2 and 10 kPa CO2) modified atmosphere improved the marketability by 30%, whereas the storage at 8 °C caused a dangerous reduction in O2 partial pressure inside modified atmosphere packages, due to fruits' increased metabolic activity. A very low level of initial microbial growth was detected, while a severe increase in mesophilic and psychrophilic bacteria was shown in control samples at both temperatures during storage; an inhibitory effect of modified atmosphere on microbial growth was also observed. In conclusion, modified atmosphere improved only the marketability of fruits stored at 4 °C; whereas the storage at 8 °C resulted in deleterious effects on the ready-to-eat fruits, whether stored in air or in modified atmosphere.

  11. Infrared band absorptance correlations and applications to nongray radiation. [mathematical models of absorption spectra for nongray atmospheres in order to study air pollution

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Manian, S. V. S.

    1976-01-01

    Various mathematical models for infrared radiation absorption spectra for atmospheric gases are reviewed, and continuous correlations for the total absorptance of a wide band are presented. Different band absorptance correlations were employed in two physically realistic problems (radiative transfer in gases with internal heat source, and heat transfer in laminar flow of absorbing-emitting gases between parallel plates) to study their influence on final radiative transfer results. This information will be applied to the study of atmospheric pollutants by infrared radiation measurement.

  12. How Well Will MODIS Measure Top of Atmosphere Aerosol Direct Radiative Forcing?

    NASA Technical Reports Server (NTRS)

    Remer, Lorraine A.; Kaufman, Yoram J.; Levin, Zev; Ghan, Stephen; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The new generation of satellite sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS) will be able to detect and characterize global aerosols with an unprecedented accuracy. The question remains whether this accuracy will be sufficient to narrow the uncertainties in our estimates of aerosol radiative forcing at the top of the atmosphere. Satellite remote sensing detects aerosol optical thickness with the least amount of relative error when aerosol loading is high. Satellites are less effective when aerosol loading is low. We use the monthly mean results of two global aerosol transport models to simulate the spatial distribution of smoke aerosol in the Southern Hemisphere during the tropical biomass burning season. This spatial distribution allows us to determine that 87-94% of the smoke aerosol forcing at the top of the atmosphere occurs in grid squares with sufficient signal to noise ratio to be detectable from space. The uncertainty of quantifying the smoke aerosol forcing in the Southern Hemisphere depends on the uncertainty introduced by errors in estimating the background aerosol, errors resulting from uncertainties in surface properties and errors resulting from uncertainties in assumptions of aerosol properties. These three errors combine to give overall uncertainties of 1.5 to 2.2 Wm-2 (21-56%) in determining the Southern Hemisphere smoke aerosol forcing at the top of the atmosphere. The range of values depend on which estimate of MODIS retrieval uncertainty is used, either the theoretical calculation (upper bound) or the empirical estimate (lower bound). Strategies that use the satellite data to derive flux directly or use the data in conjunction with ground-based remote sensing and aerosol transport models can reduce these uncertainties.

  13. A Sensitivity Study of Radiative Fluxes at the Top of Atmosphere to Cloud-Microphysics and Aerosol Parameters in the Community Atmosphere Model CAM5

    SciTech Connect

    Zhao, Chun; Liu, Xiaohong; Qian, Yun; Yoon, Jin-Ho; Hou, Zhangshuan; Lin, Guang; McFarlane, Sally A.; Wang, Hailong; Yang, Ben; Ma, Po-Lun; Yan, Huiping; Bao, Jie

    2013-11-08

    In this study, we investigated the sensitivity of net radiative fluxes (FNET) at the top of atmosphere (TOA) to 16 selected uncertain parameters mainly related to the cloud microphysics and aerosol schemes in the Community Atmosphere Model version 5 (CAM5). We adopted a quasi-Monte Carlo (QMC) sampling approach to effectively explore the high dimensional parameter space. The output response variables (e.g., FNET) were simulated using CAM5 for each parameter set, and then evaluated using generalized linear model analysis. In response to the perturbations of these 16 parameters, the CAM5-simulated global annual mean FNET ranges from -9.8 to 3.5 W m-2 compared to the CAM5-simulated FNET of 1.9 W m-2 with the default parameter values. Variance-based sensitivity analysis was conducted to show the relative contributions of individual parameter perturbation to the global FNET variance. The results indicate that the changes in the global mean FNET are dominated by those of cloud forcing (CF) within the parameter ranges being investigated. The size threshold parameter related to auto-conversion of cloud ice to snow is confirmed as one of the most influential parameters for FNET in the CAM5 simulation. The strong heterogeneous geographic distribution of FNET variation shows parameters have a clear localized effect over regions where they are acting. However, some parameters also have non-local impacts on FNET variance. Although external factors, such as perturbations of anthropogenic and natural emissions, largely affect FNET variations at the regional scale, their impact is weaker than that of model internal parameters in terms of simulating global mean FNET in this study. The interactions among the 16 selected parameters contribute a relatively small portion of the total FNET variations over most regions of the globe. This study helps us better understand the CAM5 model behavior associated with parameter uncertainties, which will aid the next step of reducing model

  14. Improvement in Clouds and the Earth's Radiant Energy System/Surface and Atmosphere Radiation Budget Dust Aerosol Properties, Effects on Surface Validation of Clouds and Radiative Swath

    SciTech Connect

    Rutan, D.; Rose, F.; Charlock, T.P.

    2005-03-18

    Within the Clouds and the Earth's Radiant Energy System (CERES) science team (Wielicki et al. 1996), the Surface and Atmospheric Radiation Budget (SARB) group is tasked with calculating vertical profiles of heating rates, globally, and continuously, beneath CERES footprint observations of Top of Atmosphere (TOA) fluxes. This is accomplished using a fast radiative transfer code originally developed by Qiang Fu and Kuo-Nan Liou (Fu and Liou 1993) and subsequently highly modified by the SARB team. Details on the code and its inputs can be found in Kato et al. (2005) and Rose and Charlock (2002). Among the many required inputs is characterization of the vertical column profile of aerosols beneath each footprint. To do this SARB combines aerosol optical depth information from the moderate-resolution imaging spectroradiometer (MODIS) instrument along with aerosol constituents specified by the Model for Atmosphere and Chemical Transport (MATCH) of Collins et al. (2001), and aerosol properties (e.g. single scatter albedo and asymmetry parameter) from Tegen and Lacis (1996) and OPAC (Hess et al. 1998). The publicly available files that include these flux profiles, called the Clouds and Radiative Swath (CRS) data product, available from the Langley Atmospheric Sciences Data Center (http://eosweb.larc.nasa.gov/). As various versions of the code are completed, publishable results are named ''Editions.'' After CRS Edition 2A was finalized it was found that dust aerosols were too absorptive. Dust aerosols have subsequently been modified using a new set of properties developed by Andy Lacis and results have been released in CRS Edition 2B. This paper discusses the effects of changing desert dust aerosol properties, which can be significant for the radiation budget in mid ocean, a few thousand kilometers from the source regions. Resulting changes are validated via comparison of surface observed fluxes from the Saudi Solar Village surface site (Myers et al. 1999), and the E13 site

  15. Does Cation Size Affect Occupancy and Electrostatic Screening of the Nucleic Acid Ion Atmosphere?

    PubMed

    Gebala, Magdalena; Bonilla, Steve; Bisaria, Namita; Herschlag, Daniel

    2016-08-31

    Electrostatics are central to all aspects of nucleic acid behavior, including their folding, condensation, and binding to other molecules, and the energetics of these processes are profoundly influenced by the ion atmosphere that surrounds nucleic acids. Given the highly complex and dynamic nature of the ion atmosphere, understanding its properties and effects will require synergy between computational modeling and experiment. Prior computational models and experiments suggest that cation occupancy in the ion atmosphere depends on the size of the cation. However, the computational models have not been independently tested, and the experimentally observed effects were small. Here, we evaluate a computational model of ion size effects by experimentally testing a blind prediction made from that model, and we present additional experimental results that extend our understanding of the ion atmosphere. Giambasu et al. developed and implemented a three-dimensional reference interaction site (3D-RISM) model for monovalent cations surrounding DNA and RNA helices, and this model predicts that Na(+) would outcompete Cs(+) by 1.8-2.1-fold; i.e., with Cs(+) in 2-fold excess of Na(+) the ion atmosphere would contain an equal number of each cation (Nucleic Acids Res. 2015, 43, 8405). However, our ion counting experiments indicate that there is no significant preference for Na(+) over Cs(+). There is an ∼25% preferential occupancy of Li(+) over larger cations in the ion atmosphere but, counter to general expectations from existing models, no size dependence for the other alkali metal ions. Further, we followed the folding of the P4-P6 RNA and showed that differences in folding with different alkali metal ions observed at high concentration arise from cation-anion interactions and not cation size effects. Overall, our results provide a critical test of a computational prediction, fundamental information about ion atmosphere properties, and parameters that will aid in the

  16. Screening Method for calculating Global Warming Potential through computational and experimental investigations of radiative forcing and atmospheric lifetime

    NASA Astrophysics Data System (ADS)

    Bevington, C. B.; Betowski, D.; Ottinger, D.; Sheppard, M.; Elrod, M. J.; Offenberg, J.; Hetfield, C.; Libelo, E. L.

    2011-12-01

    The universe of chemical substances in commerce that may have significant atmospheric impacts such as global warming potential, ozone depletion potential, and ozone creation potential is not well defined. Staff from the U.S. E.P.A. have developed a screening method and evaluated chemicals using criteria indicative of potential atmospheric impact. Screening criteria included physical chemical properties such as boiling point and vapor pressure as well as structural characteristics such as molecular weight and number of halogen atoms. Preliminary results show that there are over 1,000 chemicals with a 100-year time horizon Global Warming Potential (GWP) of greater than 1 and over 700 chemicals with a GWP of greater than 10, relative to a value of 1 for CO2. The primary goal of this scoping project is to calculate the GWP for each of these chemicals. GWP is calculated using three primary inputs: molecular weight, atmospheric lifetime, and radiative forcing. Where available, experimentally derived radiative forcing and atmospheric lifetime values have been identified and are utilized. Surprisingly, measured values were only available for approximately 20% of chemicals. Where measured data were not available, values were estimated in various ways. Besides calculating these values, characterizing the accuracy and efficacy of these various estimation methods, is also of interest. Radiative efficiency was calculated using quantum mechanical ab initio methods, utilizing Gaussian software. In addition, a preliminary Quantitative Structure Activity Relationship (QSAR) building on the work of Bera et al's "Design strategies to minimize the radiative efficiency of global warming molecules" (2010) was used to estimate radiative forcing for over 800 fluorinated chemicals. For atmospheric lifetime, QSARs were used to estimate OH rate constants and atmospheric lifetime values. Recognizing the limitations and uncertainty introduced by using QSARs for atmospheric lifetime estimation

  17. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    NASA Astrophysics Data System (ADS)

    Strada, S.; Unger, N.

    2015-09-01

    A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (all anthropogenic, biomass burning and non-biomass burning) are investigated by performing sensitivity experiments. On the global scale, our results show that land carbon fluxes (GPP and isoprene emission) are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse) by ~ 9 %. At the regional scale, plant productivity (GPP) and isoprene emission show a robust but opposite sensitivity to pollution aerosols, in regions where complex canopies dominate. In eastern North America and Europe, anthropogenic pollution aerosols (mainly from non-biomass burning sources) enhance GPP by +8-12 % on an annual average, with a stronger increase during the growing season (> 12 %). In the Amazon basin and central Africa, biomass burning aerosols increase GPP by +2-5 % on an annual average, with a peak in the Amazon basin during the dry-fire season (+5-8 %). In Europe and China, anthropogenic pollution aerosols drive a decrease in isoprene emission of -2 to -12 % on the annual average. Anthropogenic aerosols affect land carbon fluxes via different mechanisms and we suggest that the dominant mechanism varies across regions: (1) light scattering dominates in the eastern US; (2) cooling in the Amazon basin; and (3) reduction in direct radiation in Europe and China.

  18. Inconstant sun: how solar evolution has affected cosmic and ultraviolet radiation exposure over the history of life on Earth.

    PubMed

    Karam, P Andrew

    2003-03-01

    Four billion years ago, sea-level UV exposure was more than 400 times as intense as today, the dose from solar cosmic rays was five times present levels, and galactic cosmic rays accounted for only about 10% their current contribution to sea-level radiation doses. Exposure to cosmic radiation accounts for about 10% of natural background radiation exposure today and includes dose from galactic cosmic rays and solar charged particles. There is little exposure to ionizing wavelengths of UV due to absorption by ozone. The sun has evolved significantly over its life; in the past there were higher levels of particulate radiation and lower UV emissions from the sun, and a stronger solar wind reduced radiation dose in the inner solar system from galactic cosmic rays. Finally, since the early atmosphere contained little to no oxygen, surface levels of UV radiation were far higher in the past.

  19. Inconstant sun: how solar evolution has affected cosmic and ultraviolet radiation exposure over the history of life on Earth.

    PubMed

    Karam, P Andrew

    2003-03-01

    Four billion years ago, sea-level UV exposure was more than 400 times as intense as today, the dose from solar cosmic rays was five times present levels, and galactic cosmic rays accounted for only about 10% their current contribution to sea-level radiation doses. Exposure to cosmic radiation accounts for about 10% of natural background radiation exposure today and includes dose from galactic cosmic rays and solar charged particles. There is little exposure to ionizing wavelengths of UV due to absorption by ozone. The sun has evolved significantly over its life; in the past there were higher levels of particulate radiation and lower UV emissions from the sun, and a stronger solar wind reduced radiation dose in the inner solar system from galactic cosmic rays. Finally, since the early atmosphere contained little to no oxygen, surface levels of UV radiation were far higher in the past. PMID:12645767

  20. Model evaluation of the radiative and temperature effects of the ozone content changes in the global atmosphere of 1980's

    NASA Technical Reports Server (NTRS)

    Karol, Igor L.; Frolkis, Victor A.

    1994-01-01

    Radiative and temperature effects of the observed ozone and greenhouse gas atmospheric content changes in 1980 - 1990 are evaluated using the two-dimensional energy balance radiative-convective model of the zonally and annually averaged troposphere and stratosphere. Calculated radiative flux changes for standard conditions quantitatively agree with their estimates in WMO/UNEP 1991 review. Model estimates indicate rather small influence of ozone depletion in the lower stratosphere on the greenhouse tropospheric warming rate, being more significant in the non-tropical Southern Hemisphere. The calculated cooling of the lower stratosphere is close to the observed temperature trends there in the last decade.

  1. Studies of atmosphere radio-sounding for monitoring of radiation environments around nuclear power plants

    NASA Astrophysics Data System (ADS)

    Boyarchuk, Kirill; Karelin, Alexander; Tumanov, Mikhail

    2014-05-01

    The nuclear power plants practically do not discharge to the atmosphere any products causing significant radioactive contaminations. However, during the years of the nuclear power industry, some large accidents occurred at the nuclear objects, and that caused enormous environmental contamination. Among the most significant accidents are: thermal explosion of a reservoir with high-level wastes at the Mayak enterprise in the South Ural region, near the town of Kyshtym, in the end of September 1957; accident at the nuclear power plant in Windscale, UK, in October 1957; accident at the Three-Mile Island, USA, in 1979; accident at the Chernobyl power plant in April 1986. In March of 2011, a large earthquake and the following tsunami caused the largest nuclear catastrophe of XXI century, the accident at the Fucushima-1 power plant. The last accident highlighted the need to review seriously the safety issues at the active power plants and to develop the new effective methods for remote detection and control over radioactive environmental contamination and over general geophysical situation in the areas. The main influence of the fission products on the environment is its ionisation, and therefore various detectable biological and physical processes that are caused by ions. Presence of an ionisation source within the area under study may cause significant changes of absolute humidity and, that is especially important, changes of the chemical potential of atmosphere vapours indicating presence of charged condensation centres. These effects may cause anomalies in the IR radiation emitted from the Earth surface and jumps in the chemical potentials of water vapours that may be observed by means of the satellite remote sensing by specialized equipment (works by Dimitar Ouzounov, Sergey Pulinets, e.a.). In the current study, the theoretical description is presented from positions of the molecular-kinetic condensation theory that shows significant changes of the absolute and

  2. Effect of atmospheric refraction on radiative transfer in visible and near-infrared band: Model development, validation, and applications

    NASA Astrophysics Data System (ADS)

    Hu, Shuai; Gao, Tai-chang; Li, Hao; Liu, Lei; Liu, Xi-chuan; Zhang, Ting; Cheng, Tian-ji; Li, Wan-tong; Dai, Zhong-hua; Su, Xiaojian

    2016-03-01

    Refraction is an important factor influencing radiative transfer since it can modify the propagation trajectory and polarization states of lights; therefore, it is necessary to quantitively evaluate the effect of atmospheric refraction on radiative transfer process. To this end, a new atmospheric radiative transfer model including refraction process is proposed. The model accuracy is validated against benchmark results, literature results, and well-tested radiative transfer models such as discrete coordinate method and RT3/PolRadtran. The impact of atmospheric refraction on both polarized radiance and fluxes is discussed for pure Rayleigh scattering atmosphere, atmosphere with aerosol, and cloud. The results show that atmospheric refraction has a significant influence on both the radiance and polarization states of diffuse light, where the relative change of the radiance of reflected light and transmitted light due to refraction can achieve 6.3% and 7.4% for Rayleigh scattering atmosphere, 7.2% and 7.8% for atmosphere with aerosol, and 6.2% and 6.8% for cloudy atmosphere, respectively. The relative change of the degree of polarization ranges from near zero in the horizon to 9.5% near neutral points. The angular distribution pattern of the relative change of the radiance for atmosphere with aerosol and cloud is very similar to that for pure Rayleigh scattering case, where its magnitude decreases gradually with the increasing of zenith angle for reflected light; but for transmitted light, the variation characteristics is opposite. The impact of refraction is gradually enhanced with the increasing of solar zenith angles and the optical depth of aerosol and cloud. As the wavelength of incident light increases, the impact declines rapidly for Rayleigh scattering medium. The relative change of the fluxes due to refraction is most notable for Middle Latitude Winter profile (about 8.2043% and 7.3225% for the transmitted and reflected light, respectively, at 0.35 µm). With

  3. Optical constants of sulphuric acid in the far infrared. [laboratory spectra for radiative transfer measurements of Venus atmosphere

    NASA Technical Reports Server (NTRS)

    Jones, A. D.

    1976-01-01

    The IR absorption spectrum of a 75% sulphuric acid solution is obtained experimentally in the 20-50 micron wavelength region. The complex refractive index is determined from these measurements by integration of the Kramers-Kronig dispersion relation. The application of this data to radiative transfer processes in the atmosphere of Venus is briefly discussed.

  4. Influence on the atmospheric general circulation caused by the direct effect which dust exerts on radiation process

    NASA Astrophysics Data System (ADS)

    Chiba, M.

    2004-12-01

    The total amount of the soil particle (Aeolian-dust) danced by the wind from the dryness area is called annual 1000-3000Tg on the whole earth. The thing from Sahara Desert in North Africa occupies more than the half of these. The small particle of particle diameter piles up into the atmosphere among the danced soil particles for a long period of time (being weight quantity around about 1%). The particle which piles up into the atmosphere has the work which is scattered about or absorbs solar radiation. On the other hand, aeolian dust has the work which performs absorption and discharge as black-body to infrared radiation, and serves as a substance which has greenhouse effect to an earth air system. We developed an general circulation model (MASINGAR) incorporating each model about the radiation process in consideration of the influence on the solar radiation by generating of aeolian dust, transportation, each self-possessed process, and dust, and infrared radiation. The numerical experiment about influence done to the atmospheric general circulation of aeolian dust using this was conducted.

  5. Nitrogen and carbon cycling in a grassland community ecosystem as affected by elevated atmospheric CO2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing global atmospheric CO2 concentration has led to concerns regarding its potential effects on terrestrial ecosystem and the long-term storage of C and N in soil. This study examined responses to elevated CO2 in a grass ecosystem invaded with a leguminous shrub Acacia farnesiana (L.) Willd (...

  6. 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.

  7. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    NASA Astrophysics Data System (ADS)

    Teperik, Tatiana V.; de Lustrac, André

    2015-12-01

    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  8. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    SciTech Connect

    Teperik, Tatiana V.; Lustrac, André de

    2015-12-15

    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  9. Lightning driven inner radiation belt energy deposition into the atmosphere: regional and global estimates

    NASA Astrophysics Data System (ADS)

    Rodger, C. J.; Clilverd, M. A.; Thomson, N. R.; Nunn, D.; Lichtenberger, J.

    2005-12-01

    In this study we examine energetic electron precipitation fluxes driven by lightning, in order to determine the global distribution of energy deposited into the middle atmosphere. Previous studies using lightning-driven precipitation burst rates have estimated losses from the inner radiation belts. In order to confirm the reliability of those rates and the validity of the conclusions drawn from those studies, we have analyzed New Zealand data to test our global understanding of troposphere to magnetosphere coupling. We examine about 10000h of AbsPAL recordings made from 17 April 2003 through to 26 June 2004, and analyze subionospheric very-low frequency (VLF) perturbations observed on transmissions from VLF transmitters in Hawaii (NPM) and western Australia (NWC). These observations are compared with those previously reported from the Antarctic Peninsula. The perturbation rates observed in the New Zealand data are consistent with those predicted from the global distribution of the lightning sources, once the different experimental configurations are taken into account. Using lightning current distributions rather than VLF perturbation observations we revise previous estimates of typical precipitation bursts at L~2.3 to a mean precipitation energy flux of ~1×10-3 ergs cm-2s-1. The precipitation of energetic electrons by these bursts in the range L=1.9-3.5 will lead to a mean rate of energy deposited into the atmosphere of 3×10-4 ergs cm-2min-1, spatially varying from a low of zero above some ocean regions to highs of ~3-6×10-3 ergs cm-2min-1 above North America and its conjugate region.

  10. Deriving aerosol properties from measurements of the Atmosphere-Surface Radiation Automatic Instrument (ASRAI)

    NASA Astrophysics Data System (ADS)

    Xu, Hua; Li, Donghui; Li, Zhengqiang; Zheng, Xiaobing; Li, Xin; Xie, Yisong; Liu, Enchao

    2015-10-01

    The Atmosphere-surface Radiation Automatic Instrument (ASRAI) is a newly developed hyper-spectral apparatus by Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (AIOFM, CAS), measuring total spectral irradiance, diffuse spectral irradiance of atmosphere and reflected radiance of the land surface for the purpose of in-situ calibration. The instrument applies VIS-SWIR spectrum (0.4~1.0 μm) with an averaged spectral resolution of 0.004 μm. The goal of this paper is to describe a method of deriving both aerosol optical depth (AOD) and aerosol modes from irradiance measurements under free cloudy conditions. The total columnar amounts of water vapor and oxygen are first inferred from solar transmitted irradiance at strong absorption wavelength. The AOD together with total columnar amounts of ozone and nitrogen dioxide are determined by a nonlinear least distance fitting method. Moreover, it is able to infer aerosol modes from the spectral dependency of AOD because different aerosol modes have their inherent spectral extinction characteristics. With assumption that the real aerosol is an idea of "external mixing" of four basic components, dust-like, water-soluble, oceanic and soot, the percentage of volume concentration of each component can be retrieved. A spectrum matching technology based on Euclidean-distance method is adopted to find the most approximate combination of components. The volume concentration ratios of four basic components are in accordance with our prior knowledge of regional aerosol climatology. Another advantage is that the retrievals would facilitate the TOA simulation when applying 6S model for satellite calibration.

  11. EOS Interdisciplinary Investigation: Observational and Modeling Studies of Radiative, Chemical, and Dynamical Interactions in the Earth's Atmosphere

    NASA Technical Reports Server (NTRS)

    Salby, Murry L.

    1998-01-01

    A 3-dimensional model of atmospheric dynamics and photochemistry has been developed from the primitive equations in isentropic coordinates. The model extends from the upper troposphere through the middle atmosphere and is driven by observed dynamical and chemical structure in the troposphere. The model's formulation is entirely spectral: Horizontal structure is represented in terms of vector Hough functions, which explicitly partition the motion into its rotational and divergent components. This formulation enables the model's computational performance to be increased dramatically by filtering high-frequency gravity waves, which do not affect PV conservation. Vertical structure is represented in terms of eigenfunctions that follow from the primitive equations in isentropic coordinates. The model's fully spectral formulation enables scale-selective dissipation, necessary for numerical stability, to be applied at 6th order-in all 3 coordinate directions. This feature leaves all but the shortest vertical scales undamped and, consequently, allows potential vorticity and chemical tracers to be conserved quite accurately, distinctly better than in the model's layered counterpart. These dynamical features are complemented by a basic but fairly complete treatment of gas phase photochemistry, which accounts for some 48 chemical species, diurnally-varying SW absorption by O2 and O3, and LW cooling calculated via a detailed band calculation of radiative transfer. Driven by observed tropospheric structure, the 3D model reproduces observed structure in the middle atmosphere, inclusive of transport by the Brewer-Dobson circulation and accompanying chemical variations. Calculated residual motion is consistent with diabatic cooling rates, poleward transport, and descent in the polar night derived from satellite measurements of chemical tracers made from LIMS, SAGE, and UARS. The model also reproduces the observed structure of chemical species like O3, HNO3, and ClO. At the same

  12. Moisture and temperature balances at the Atmospheric Radiation Measurement Southern Great Plains Site in forecasts with the Community Atmosphere Model (CAM2)

    NASA Astrophysics Data System (ADS)

    Williamson, D. L.; Boyle, J.; Cederwall, R.; Fiorino, M.; Hnilo, J.; Olson, J.; Phillips, T.; Potter, G.; Xie, S. C.

    2005-08-01

    We compare the balance of terms in moisture and temperature prediction equations during short forecasts by the Community Atmosphere Model (CAM2) with observed estimates at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site for two intensive observing periods (IOPs). The goal is to provide insight into parameterization errors which ultimately should lead to model improvements. The atmospheric initial conditions are obtained from high-resolution numerical weather prediction (NWP) analyses. The land initial conditions are spun up to be consistent with those analyses. Three cases are considered: (1) June/July 1997 when the atmosphere is relatively moist and surface evaporation corresponds to 90% of the precipitation with advection accounting for the remainder; (2) rainy days in April 1997 when the atmosphere is less moist and horizontal advection accounts for much of the precipitation with a small contribution from surface evaporation and the balance being derived from the water already present in the column; and (3) nonrainy days of the April 1997 when the moist process parameterizations are inactive and the planetary boundary layer (PBL) parameterization is dominant. For the first case the Zhang-McFarlane deep convective parameterization drives the model to a wrong state. For the second the Hack shallow convective parameterization appears to be not acting deep enough. During both periods inconsistencies between CAM2 and ARM surface fluxes, land surface conditions and the net surface radiative fluxes indicate that the exchange parameterizations should be examined further. For the third case the PBL parameterization does not appear to create the correct vertical structure. In addition, the individual components of the dynamical tendency are very different between CAM2 and ARM, although the total dynamical tendency is similar in the two. Although these observations do not imply that those components are themselves wrong since they may be responding

  13. Atmospheric Radiation Measurement (ARM) Data from the Tropical Western Pacific (TWP) Site.

    DOE Data Explorer

    The Atmospheric Radiation Measurement (ARM) Program is the largest global change research program supported by the U.S. Department of Energy. The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. To achieve this goal, ARM scientists and researchers around the world use continuous data obtained through the ARM Climate Research Facility. ARM maintains four major, permanent sites for data collection and deploys the ARM Mobile Facility to other sites as determined. The Tropical Western Pacific (TWP) site is one of the four fixed sites. It consists of three climate research facilities; the Manus facility on Los Negros Island in Manus, Papua New Guinea (established in 1996); the Nauru facility on Nauru Island, Republic of Nauru (1998); and the Darwin facility in Darwin, Northern Territory, Australia (2002). The operations are supported by government agencies in each host country. Covering the area roughly between 10 degrees N and 10 degrees S of the equator and from 130 degrees E to 167 degrees E, the TWP locale includes a region that plays a large role in the interannual variability observed in the global climate system. More than 250,000 TWP data sets from 1996 to the present reside in the ARM Archive. Begin at the TWP information page for links or access data directly from the ARM Archive at http://www.archive.arm.gov/. Users will need to register for a password, but all files are then free for viewing or downloading. The ARM Archive physically resides at the Oak Ridge National Laboratory.

  14. A Midlatitude Cirrus Cloud Climatology from the Facility for Atmospheric Remote Sensing. Part III: Radiative Properties

    SciTech Connect

    Sassen, K.; Comstock, Jennifer M.

    2001-08-01

    In Part III of a series of papers describing the extended time high-cloud observations from the University of Utah Facility for Atmospheric Remote Sensing (FARS) supporting the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment, the visible and infrared radiative properties of cirrus clouds over Salt Lake City, Utah, are examined. Using {approx}860 h of combined ruby (0.694 {micro}m) lidar and midinfrared (9.5-11.5 {micro}m) radiometer data collected between 1992 and 1999 from visually identified cirrus clouds, the visible optical depths {tau} and infrared layer emittance epsilon of the varieties of midlatitude cirrus are characterized. The mean and median values for the cirrus sample are 0.75 {+-} 0.91 and 0.61 for {tau}, and 0.30 {+-} 0.22 and 0.25 for epsilon. Other scattering parameters studied are the visible extinction and infrared absorption coefficients, and their ratio, and the lidar backscatter-to-extinction ratio, which has a mean value of 0.041 sr{sup -1}. Differences among cirrus clouds generated by general synoptic (e.g., jet stream), thunderstorm anvil, and orographic mechanisms are found, reflecting basic cloud microphysical effects. The authors draw parameterizations in terms of midcloud temperature T{sub m} and physical cloud thickness {Delta}z for epsilon and {tau}: both macrophysical variables are needed to adequately address the impact of the adiabatic process on ice cloud content, which modulates radiative transfer as a function of temperature. For the total cirrus dataset, the authors find epsilon = 1 -exp [-8.5 x 10{sup -5} (T{sub m} + 80 C) {Delta}z]. These parameterizations, based on a uniquely comprehensive dataset, hold the potential for improving weather and climate model predictions, and satellite cloud property retrieval methods.

  15. Atmospheric depression-mediated water temperature changes affect the vertical movement of chum salmon Oncorhynchus keta.

    PubMed

    Kitagawa, Takashi; Hyodo, Susumu; Sato, Katsufumi

    2016-08-01

    The Sanriku coastal area, Japan, is one of the southern-most natural spawning regions of chum salmon Oncorhynchus keta. Here, we report their behavioral response to changes in ambient temperature after the passage of an atmospheric depression during the early spawning season. Before the passage, all electrically tagged fish moved vertically for several hours to depths below the shallow thermocline at >100 m. However, during the atmospheric depression, the salmon shortened the duration of their vertical movements and spent most time at the surface. The water column was homogenous at <150 m deep except for the surface. The descending behavior may have been discontinued because the cooler water below the thermocline was no longer in a thermally defined layer, due to strong vertical mixing by high wave action. Instead, they likely spent time within the cooler water temperatures at the surface of bays to minimize metabolic energy cost during migration.

  16. Simultaneous Precipitation of Solar Protons and Relativistic Electrons as a New Factor Affecting the Earth's Atmosphere

    NASA Astrophysics Data System (ADS)

    Shirochkov, A. V.; Sokolov, S. N.

    In the field of solar - terrestrial physics during the last decade there has been renewed interest in the effects produced in the Earth atmosphere and ionosphere by fluxes of precipitated highly relativistic electrons. A series of investigation on the subject (preferably by means of satellite measurements) was performed recently, which discussed different aspects of these phenomena called HRE events. More careful study of the HRE events revealed previously unnoticed geophysical phenomenon: a great majority of the solar proton events (SPE) were accompanied by simultaneous precipitation of relativistic electron fluxes. The studies of previous SPE events attributed their atmospheric and ionospheric effects entirely to the solar proton fluxes. It turned out that such an assumption is wrong. Therefore we have actually a new class of geophysical phenomena when the Earth's atmosphere and ionosphere experience combined impact of simultaneously precipitating fluxes of solar protons and relativistic electrons. If one takes into accounts effect of enhanced density of the solar wind during the SPEs (i.e. its dynamic pressure) the real situation during these combined events became more complicated. In this paper the effects during the storm of May 1992 are analyzed as an example of such unusual combination. The methods of separation of the effects produced by different precipitation particles are presented. Other similar events are considered to demonstrate that such complex events are not unique geophysical phenomena.

  17. Atmospheric Deposition of Organic Carbon in Pennsylvania as Affected by Climatic Factors

    NASA Astrophysics Data System (ADS)

    Iavorivska, L.; Boyer, E. W.; Grimm, J.; Fuentes, J. D.

    2014-12-01

    Organic matter which is usually expressed through measurements of dissolved organic carbon (DOC) is ubiquitous in atmospheric water. It plays an important role in cloud formation processes, and contributes to organic acidity of precipitation. Rain and snow deposited to the landscape is a source of nutrient enrichment to ecosystems and water bodies, and is especially important as an input of carbon in coastal regions. Since DOC is highly chemically reactive and bioavailable it influences rates of primary and secondary productivity in aquatic ecosystems. Despite the significance of DOC to many ecosystem processes, knowledge about its contributions to landscapes in precipitation remains limited. Here, we quantified the removal of DOC from the atmosphere via precipitation over space and time in order to assess the magnitude of wet deposition as a link between terrestrial and aquatic components of the carbon cycle. Further, we consider the predictability of organic matter in precipitation as a function of hydro-chemical and climatic variables. We measured DOC concentration and composition in storm events both sequentially (hourly during events) and seasonally (weekly over the year). Data on the chemical composition of precipitation, along with meteorological back-trajectory analyses help clarify how an interplay between emission sources, atmospheric transport and climatic conditions determine the abundance of rainwater DOC across Pennsylvania.

  18. Study of cloud enhanced surface UV radiation at the atmospheric observatory of Southern Patagonia, Río Gallegos, Argentina

    NASA Astrophysics Data System (ADS)

    Wolfram, Elian A.; Salvador, Jacobo; Orte, Facundo; Bulnes, Daniela; D'Elia, Raul; Antón, Manuel; Alados-Arboledas, Lucas; Quel, Eduardo

    2013-05-01

    Ozone and ultraviolet (UV) radiation are two important issues in the study of Earth's atmosphere. The anthropogenic perturbation of the ozone layer has induced change in the amount of UV radiation that reaches the Earth's surface, mainly through the Antarctic ozone hole. Also clouds have been identified as the main modulator of UV amount over short time scales. While clouds can decrease direct radiation, they can produce an increase in the diffuse component, and as a consequence the surface UV radiation may be higher than during an equivalent clear sky scenario. In particular this situation can be important when a low ozone column and partially cloud coverered skies occur simultaneously. These situations happen frequently in southern Patagonia, where the CEILAP Lidar Division has established the Atmospheric Observatory of Southern Patagonia, an atmospheric remote sensing site near the city of Río Gallegos (51°55'S, 69°14'W). In this paper, the impact of clouds on UV radiation is investigated by the use of ground based measurements from the passive remote sensing instruments operating at this site, mainly broad and moderate narrow band filter radiometers. Cloud modification factors (CMF, ratio between the measured UV radiation in a cloudy sky and the simulated radiation under cloud-free conditions) are evaluated for the study site. CMFs higher than 1 are found during spring and summer time, when lower total ozone columns, higher solar elevations and high cloud cover occur simultaneously, producing extreme erythemal irradiance at the ground surface. Enhancements as high as 25% were registered. The maximum duration of the enhancement was around 30 minutes. This produces dangerous sunbathing conditions for the Río Gallegos citizen.

  19. Radiative analysis of global mean temperature trends in the middle atmosphere: Effects of non-locality and secondary absorption bands

    NASA Astrophysics Data System (ADS)

    Fomichev, V. I.; Jonsson, A. I.; Ward, W. E.

    2016-02-01

    In this paper, we provide a refined and extended assignment of past and future temperature changes relative to previous analyses and describe and evaluate the relevance of vertical coupling and non-linear and secondary radiative mechanisms for the interpretation of climatic temperature variations in the middle atmosphere. Because of their nature, the latter mechanisms are not adequately accounted for in most regression analyses of temperature trends as a function of local constituent variations. These mechanisms are examined using (1) globally averaged profiles from transient simulations with the Canadian Middle Atmosphere Model (CMAM) forced by changes in greenhouse gases and ozone depleting substances and (2) a one-dimensional radiative-equilibrium model forced using the diagnosed global mean changes in radiatively active constituents as derived from the CMAM model runs. The conditions during the periods 1975 to 1995 and 2010 to 2040 (during which the rates of change in ozone and CO2 differ) provide a suitable contrast for the role of the non-linear and non-local mechanisms being evaluated in this paper to be clearly differentiated and evaluated. Vertical coupling of radiative transfer effects and the influence of secondary absorption bands are important enough to render the results of multiple linear regression analyses between the temperature response and constituent changes misleading. These effects are evaluated in detail using the 1D radiative-equilibrium model using profiles from the CMAM runs as inputs. In order to explain the differences in the CMAM temperature trends prior to and after 2000 these other radiative effects must be considered in addition to local changes in the radiatively active species. The middle atmosphere temperature cools in response to CO2 and water vapor increases, but past and future trends are modulated by ozone changes.

  20. Missing data imputation of solar radiation data under different atmospheric conditions.

    PubMed

    Turrado, Concepción Crespo; López, María Del Carmen Meizoso; Lasheras, Fernando Sánchez; Gómez, Benigno Antonio Rodríguez; Rollé, José Luis Calvo; Juez, Francisco Javier de Cos

    2014-01-01

    Global solar broadband irradiance on a planar surface is measured at weather stations by pyranometers. In the case of the present research, solar radiation values from nine meteorological stations of the MeteoGalicia real-time observational network, captured and stored every ten minutes, are considered. In this kind of record, the lack of data and/or the presence of wrong values adversely affects any time series study. Consequently, when this occurs, a data imputation process must be performed in order to replace missing data with estimated values. This paper aims to evaluate the multivariate imputation of ten-minute scale data by means of the chained equations method (MICE). This method allows the network itself to impute the missing or wrong data of a solar radiation sensor, by using either all or just a group of the measurements of the remaining sensors. Very good results have been obtained with the MICE method in comparison with other methods employed in this field such as Inverse Distance Weighting (IDW) and Multiple Linear Regression (MLR). The average RMSE value of the predictions for the MICE algorithm was 13.37% while that for the MLR it was 28.19%, and 31.68% for the IDW. PMID:25356644

  1. Theoretical studies of spectroscopic problems of importance for atmospheric radiation measurements

    NASA Technical Reports Server (NTRS)

    Tipping, Richard H.

    1994-01-01

    Many of the instruments used to deduce the physical parameters of the Earth's atmosphere necessary for climate studies or for pollution monitoring (for instance, temperature versus pressure or number densities of trace molecules) rely on the existence of accurate spectroscopic data and an understanding of the physical processes responsible for the absorption or emission of radiation. During the summer, research was either continued or begun on three distinct problems: (1) an improved theoretical framework for the calculation of the far-wing absorption of allowed spectral lines; (2) a refinement of the calculation of the collision-induced fundamental spectrum of N2; and (3) an investigation of possible line-mixing effects in the fundamental spectrum of CH4. Progress in these three areas is summarized below. During the past few years, we have developed a theoretical framework for the calculation of the absorption of radiation by the far wings of spectral lines. Such absorption due to water vapor plays a crucial role in the greenhouse effect as well as limiting the retrieval of temperature profiles from satellite data. Several improvements in the theory have been made and the results are being prepared for publication. Last year we published results for the theoretical calculation of the absorption of radiation due to the dipoles induced during binary collisions of N2 molecules using independently measured molecular parameters; the results were in reasonable agreement with experimental data. However, recent measurements have revealed new fine structure that has been attributed to line-mixing effects. We do not think that this is correct, rather that the structure results from short-range anisotropic dipoles. We are in the process of including this refinement in our theoretical calculation in order to compare with the new experimental data. Subtle changes in the spectra of CH4 measured by researchers at Langley have also been attributed to line-mixing effects. By

  2. 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

  3. Sulfur isotope dynamics in two central european watersheds affected by high atmospheric deposition of SO x

    NASA Astrophysics Data System (ADS)

    Novák, Martin; Kirchner, James W.; Groscheová, Hana; Havel, Miroslav; Černý, Jiří; Krejčí, Radovan; Buzek, František

    2000-02-01

    Sulfur fluxes and δ34S values were determined in two acidified small watersheds located near the Czech-German border, Central Europe. Sulfur of sulfate aerosol in the broader region (mean δ 34S of 7.5‰ CDT) was isotopically heavier than sulfur of airborne SO 2 (mean δ 34S of 4.7‰). The annual atmospheric S deposition to the Jezeřı´ watershed decreased markedly in 1993, 1994, and 1995 (40, 33, and 29 kg/ ha · yr), reflecting reductions in industrial S emissions. Sulfur export from Jezeří via surface discharge was twice atmospheric inputs, and increased from 52 to 58 to 85 kg/ha · yr over the same three-year period. The δ 34S value of Jezeřı´ streamflow was 4.5 ± 0.3‰, intermediate between the average atmospheric deposition (5.4 ± 0.2‰) and soil S (4.0 ± 0.5‰), suggesting that the excess sulfate in runoff comes from release of S from the soil. Bedrock is not a plausible source of the excess S, because its S concentration is very low (<0.003 wt.%) and because its δ 34S value is too high (5.8‰) to be consistent with the δ 34S of runoff. A sulfur isotope mixing model indicated that release of soil S accounted for 64 ± 33% of sulfate S in Jezeřı´ discharge. Approximately 30% of total sulfate S in the discharge were organically cycled. At Načetı´n, the same sequence of δ34S IN > δ34S OUT > δ34S SOIL was observed. The seasonality found in atmospheric input (higher δ 34S in summer, lower δ 34S in winter) was preserved in shallow (<10 cm) soil water, but not in deeper soil water. δ 34S values of deeper (>10 cm) soil water (4.8 ± 0.2‰) were intermediate between those of atmospheric input (5.9 ± 0.3‰) and Nac̆etín soils (2.4 ± 0.1‰), again suggesting that remobilization of soil S accounts for a significant fraction (roughly 40 ± 10%) of the S in soil water at Načetı´n. The inventories of soil S at both of these sites are legacies of more intense atmospheric pollution during previous decades, and are large enough (740

  4. Atmospheric measurements by Medipix-2 and Timepix Ionizing Radiation Imaging Detectors on BEXUS stratospheric balloon campaigns

    NASA Astrophysics Data System (ADS)

    Urbar, Jaroslav; Scheirich, Jan; Jakubek, Jan

    2010-05-01

    Results of the first two experiments using semiconductor pixel detectors of the Medipix family for cosmic ray imaging in the stratospheric environment are presented. The original detecting device was based on the hybrid pixel detectors of Medipix-2 and Timepix developed at CERN with USB interface developed at Institute of Experimental and Applied Physics of Czech Technical University in Prague. The detectors were used in tracking mode allowing them to operate as an "active nuclear emulsion". The actual flight time of BEXUS7 with Medipix-2 on 8th October 2008 was over 4 hours, with 2 hours at stable floating altitude of 26km. BEXUS9 measurements of similar duration by Timepix, Medipix-2 and ST-6 Geiger telescope instruments took place in arctic atmosphere below 24km altitude on 11th October 2009. This balloon platform is quite ideal for such in-situ measurements. Not only because of the high altitudes reached, but also due to its slow ascent velocity for statistically relevant sampling of the ambient environment for improving cosmic ray induced ionisation rate model inputs. The flight opportunity for BEXUS student projects was provided by Education department of the European Space Agency (ESA) and Eurolaunch - Collaboration of Swedish National Space Board (SNSB) and German Space Agency (DLR). The scientific goal was to check energetic particle type altitudinal dependencies, also testing proper detector calibration by detecting fluxes of ionizing radiation, while evaluating instrumentation endurance and performance.

  5. Thermal Infrared Spectroscopy of Atmospheric Species Critical to Radiative Forcing of Earth's Climate

    NASA Astrophysics Data System (ADS)

    Brasunas, J. C., Jr.; Kostiuk, T.; Livengood, T. A.; Hewagama, T.; Kolasinski, J. R.

    2014-12-01

    Thermal-infrared (from about 6 to 100 or more microns wavelength), emission-mode Fourier transform spectrometer (FTS) systems acquire radiometric spectra for diurnal diagnostics of atmospheric properties. We have been funded through NASA's Planetary Instrument Definition and Development Program (PIDDP) to develop CIRS-lite as a lightweight successor to the Goddard-developed Cassini CIRS FTS currently operating in Saturn orbit. CIRS-lite also has promise for Earth science due to its modest mass, power and volume requirements and novel technical capabilities. For Earth, CIRS-lite supports the characterization of climate radiative forcing, including trace species measurements such as methane. Detection capability beyond the typical limit of HgCdTe focal planes (about 16 microns wavelength) enables a more complete characterization of the greenhouse effect. As for trace-species quantification, a beyond-HgCdTe focal plane permits characterization of water without overlapping lines from other species, enabling better measurements of these other species such as methane at wavelengths reachable by HgCdTe.

  6. Hourly global and diffuse radiation of Lagos, Nigeria-correlation with some atmospheric parameters

    SciTech Connect

    Chendo, M.A.C.; Maduekwe, A.A.L. )

    1994-03-01

    The influence of four climatic parameters on the hourly diffuse fraction in Lagos, Nigeria, has been studied. Using data for two years, new correlations were established. The standard error of the Liu and Jordan-type equation was reduced by 12.83% when solar elevation, ambient temperature, and relative humidity were used together as predictor variables for the entire data set. Ambient temperature and relative humidity proved to be very important variables for predicting the diffuse fraction of the solar radiation passing through the humid atmosphere of the coastal and tropic city of Lagos. Seasonal analysis carried out with the data showed improvements on the standard errors for the new seasonal correlations. In the case of the dry season, the improvement was 18.37%, whole for the wet season, this was 12.37%. Comparison with existing correlations showed that the performance of the one parameter model (namely K[sub t]), of Orgill and Hollands and Reindl, Beckman, and Duffie were very different from the Liu and Jordan-type model obtained for Lagos.

  7. Monitoring of atmospheric gamma radiation and radon observations of rainfall events in southeast of Brazil

    NASA Astrophysics Data System (ADS)

    Martin, I. M.; Alves, M. A.; Gomes, M. P.

    2013-05-01

    It is well known that we live in an environment that is under the influence of radioactivity. Radioactive elements in Earth's crust, cosmic rays, and anthropogenic sources contribute to the radiation of different types (alpha, beta, gamma and X-rays) that can be measured. An interesting phenomenon associated with environmental radioactivity is radon washout wherein the radon gas that is produced by the decay of natural radioactive elements and released into the atmosphere is concentrated near ground by falling rain. Rain drops trap radon in their interior and transport this radioactive gas to the surface. In this study, we describe the monitoring of the localized and temporary increase in the natural radioactivity caused by radon washout using a 3"x 3" NaI(Tl) scintillator. Variations in the radioactivity were correlated with changes in meteorological conditions. We observed that even though rainfall is a main factor in the increase of natural radioactivity near ground, other factors such as the presence of fog and winds play an important role in the concentration and dispersion of radon. Because of the low cost of our experimental set up, we believe that this is an experiment that could easily be conducted in most universities and could also be used to monitor environmental radioactivity levels.

  8. Research Spotlight: Ozone recovery and climate change will affect the atmosphere near Earth's surface

    NASA Astrophysics Data System (ADS)

    Kumar, Mohi; Tretkoff, Ernie

    Ozone in the stratosphere (˜10-50 kilometers in altitude) helps protect life on Earth from harmful solar ultraviolet radiation. But at the lower altitudes in the troposphere, (0-10 kilometers in altitude), ozone is a major constituent of smog and has detrimental health effects. The stratospheric ozone layer had been depleted but recently has started to recover due to efforts to limit emissions of ozone- depleting chemicals.

  9. An efficient and accurate technique to compute the absorption, emission, and transmission of radiation by the Martian atmosphere

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee; Ackerman, Thomas P.; Pollack, James B.

    1990-01-01

    CO2 comprises 95 pct. of the composition of the Martian atmosphere. However, the Martian atmosphere also has a high aerosol content. Dust particles vary from less than 0.2 to greater than 3.0. CO2 is an active absorber and emitter in near IR and IR wavelengths; the near IR absorption bands of CO2 provide significant heating of the atmosphere, and the 15 micron band provides rapid cooling. Including both CO2 and aerosol radiative transfer simultaneously in a model is difficult. Aerosol radiative transfer requires a multiple scattering code, while CO2 radiative transfer must deal with complex wavelength structure. As an alternative to the pure atmosphere treatment in most models which causes inaccuracies, a treatment was developed called the exponential sum or k distribution approximation. The chief advantage of the exponential sum approach is that the integration over k space of f(k) can be computed more quickly than the integration of k sub upsilon over frequency. The exponential sum approach is superior to the photon path distribution and emissivity techniques for dusty conditions. This study was the first application of the exponential sum approach to Martian conditions.

  10. Atmospheric Radiation Measurement program climate research facility operations quarterly report January 1 - March 31, 2008.

    SciTech Connect

    Sisterson, D. L.

    2008-05-22

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period January 1 - March 31, 2008, for the fixed sites. The AMF is being deployed to China and is not in operation this quarter. The second quarter comprises a total of 2,184 hours. The average as well as the individual site values exceeded our goal this quarter. The Site Access Request System is a web-based database used to track visitors to the fixed and mobile sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. FKB represents the AMF statistics for the Haselbach, Germany, past deployment in 2007. NIM represents the AMF statistics for the Niamey, Niger, Africa, past deployment in 2006. PYE represents just the AMF Archive statistics for the Point Reyes, California, past deployment in 2005. In addition, users who do not want to wait for data to be provided through the ACRF Archive can request a research account on the local site data system. The seven computers for the research accounts are located at the Barrow

  11. Modeling dust as component minerals in the Community Atmosphere Model: development of framework and impact on radiative forcing

    DOE PAGES

    Scanza, R. A.; Mahowald, N.; Ghan, S.; Zender, C. S.; Kok, J. F.; Liu, X.; Zhang, Y.; Albani, S.

    2015-01-15

    The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale, using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral componentsmore » in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as + 0.05 Wm−2 for both CAM4 and CAM5 simulations with mineralogy. We compare this to the radiative forcing from simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 Wm−2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, −0.05 and −0.17 Wm−2, respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.« less

  12. Lightning-driven inner radiation belt energy deposition into the atmosphere: implications for ionisation-levels and neutral chemistry

    NASA Astrophysics Data System (ADS)

    Rodger, C. J.; Enell, C.-F.; Turunen, E.; Clilverd, M. A.; Thomson, N. R.; Verronen, P. T.

    2007-08-01

    Lightning-generated whistlers lead to coupling between the troposphere, the Van Allen radiation belts and the lower-ionosphere through Whistler-induced electron precipitation (WEP). Lightning produced whistlers interact with cyclotron resonant radiation belt electrons, leading to pitch-angle scattering into the bounce loss cone and precipitation into the atmosphere. Here we consider the relative significance of WEP to the lower ionosphere and atmosphere by contrasting WEP produced ionisation rate changes with those from Galactic Cosmic Radiation (GCR) and solar photoionisation. During the day, WEP is never a significant source of ionisation in the lower ionosphere for any location or altitude. At nighttime, GCR is more significant than WEP at altitudes <68 km for all locations, above which WEP starts to dominate in North America and Central Europe. Between 75 and 80 km altitude WEP becomes more significant than GCR for the majority of spatial locations at which WEP deposits energy. The size of the regions in which WEP is the most important nighttime ionisation source peaks at ~80 km, depending on the relative contributions of WEP and nighttime solar Lyman-α. We also used the Sodankylä Ion Chemistry (SIC) model to consider the atmospheric consequences of WEP, focusing on a case-study period. Previous studies have also shown that energetic particle precipitation can lead to large-scale changes in the chemical makeup of the neutral atmosphere by enhancing minor chemical species that play a key role in the ozone balance of the middle atmosphere. However, SIC modelling indicates that the neutral atmospheric changes driven by WEP are insignificant due to the short timescale of the WEP bursts. Overall we find that WEP is a significant energy input into some parts of the lower ionosphere, depending on the latitude/longitude and altitude, but does not play a significant role in the neutral chemistry of the mesosphere.

  13. Status of Radiative Transfer Model (RTM) development for the Northrop Grumman Venus Atmospheric Maneuverable Platform (VAMP) Technology Development Program

    NASA Astrophysics Data System (ADS)

    Wong, Eric

    2014-11-01

    In support of the Northrop Grumman/L-Garde Venus Atmospheric Maneuverable Platform (VAMP) development, we are developing a multi-purpose radiative transfer model (RTM) for the applications of the Venus atmosphere. For the solar array sizing, spectral solar radiance calculations are needed and a Correlated-k method of spectral integration will be used. This method is relatively fast computationally and typical error of the method is within a few percent, sufficiently accurate for solar array sizing analyses. For sensor characterization or sensor performance study, details of an absorption line, e.g. the near-IR “atmospheric window” absorption lines, must be used and an equivalent line-by-line calculation will be performed. At the completion of the model a large data base of radiance profiles of different atmospheric conditions will be created. The database can also be used to support thermal radiation analysis for other sub-systems. In this poster, we present our current state of the RTM development and model validation development. Additionally, we will present some preliminary comparison of top-of-atmosphere solar radiance with Venus Express VIRTIS measurements.

  14. 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

  15. Hawking radiation and the Stefan-Boltzmann law: The effective radius of the black-hole quantum atmosphere

    NASA Astrophysics Data System (ADS)

    Hod, Shahar

    2016-06-01

    It has recently been suggested (S.B. Giddings (2016) [2]) that the Hawking black-hole radiation spectrum originates from an effective quantum "atmosphere' which extends well outside the black-hole horizon. In particular, comparing the Hawking radiation power of a (3 + 1)-dimensional Schwarzschild black hole of horizon radius rH with the familiar Stefan-Boltzmann radiation power of a (3 + 1)-dimensional flat space perfect blackbody emitter, Giddings concluded that the source of the Hawking semi-classical black-hole radiation is a quantum region outside the Schwarzschild black-hole horizon whose effective radius rA is characterized by the relation Δr ≡rA -rH ∼rH. It is of considerable physical interest to test the general validity of Giddings's intriguing conclusion. To this end, we study the Hawking radiation of (D + 1)-dimensional Schwarzschild black holes. We find that the dimensionless radii rA /rH which characterize the black-hole quantum atmospheres, as determined from the Hawking black-hole radiation power and the (D + 1)-dimensional Stefan-Boltzmann radiation law, are a decreasing function of the number D + 1 of spacetime dimensions. In particular, it is shown that radiating (D + 1)-dimensional Schwarzschild black holes are characterized by the relation (rA -rH) /rH ≪ 1 in the large D ≫ 1 regime. Our results therefore suggest that, at least in some physical cases, the Hawking emission spectrum originates from quantum excitations very near the black-hole horizon.

  16. Direct method for solving transfer equation by expansion in spherical harmonics: Scattering in atmosphere with Lambertian lower boundary and thermal radiation transfer

    NASA Technical Reports Server (NTRS)

    Ustinov, Y. A.

    1978-01-01

    The direct method for the solution of the spherical harmonics approximation to the equation of transfer of radiation is applied to the cases of (1) scattering of the solar radiation in the atmosphere with the Lambertian boundary and (2) thermal radiation transfer.

  17. Projected changes in atmospheric rivers affecting Europe in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Ramos, Alexandre M.; Tomé, Ricardo; Trigo, Ricardo M.; Liberato, Margarida L. R.; Pinto, Joaquim G.

    2016-09-01

    Atmospheric Rivers (ARs) are elongated bands of high water vapor concentration extending to the midlatitudes, which can be associated with intense precipitation and floods over continental areas. We analyze ARs reaching Europe in simulations from six Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models (GCMs) to quantify possible changes during the current century, with emphasis in five western European prone coastal areas. ARs are represented reasonably well in GCMs for recent climate conditions (1980-2005). Increased vertically integrated horizontal water transport is found for 2074-2099 (RCP4.5 and RCP8.5) compared to 1980-2005, while the number of ARs is projected to double on average for the same period. These changes are robust between models and are associated with higher air temperatures and thus enhanced atmospheric moisture content, together with higher precipitation associated with extratropical cyclones. This suggests an increased risk of intense precipitation and floods along the Atlantic European Coasts from the Iberian Peninsula to Scandinavia.

  18. Climatic, tectonic, and biological factors affecting the oxidation state of the atmosphere and oceans: Implications for Phanerozoic O2 evolution

    NASA Astrophysics Data System (ADS)

    Ozaki, K.; Tajika, E.

    2015-12-01

    The Earth's atmosphere and oceans have seen fundamental changes in its oxidation state in response to the climatic, tectonic and geochemical variations. Over the past decade, several geochemical proxies have led to significant progress in understanding the paleredox states of ancient oceans. However, a quantitative interpretation of these data for atmospheric O2 levels remain unclear because the relationship between atmospheric O2 levels (pO2) and oceanic redox state depends on several environmental factors, such as terrestrial weathering rate, sea-level stands, and sinking rate of particulate organic matter (POM) in the water column and so on. It is widely thought that the redox-dependent P cycling also plays a crucial role in regulating pO2 because it acts as a negative feedback on a geological timescale. It is important that strength of this feedback for a given pO2 is also modulated by environmental factors, affecting not only O2 levels at steady state but also its susceptibility to environmental changes. In this study, a quantitative role of environmental factors in the oxidation state of Earth's surface environment is evaluated with an oceanic biogeochemical cycle model (CANOPS) coupled with global C cycle model, which enables us to understand the ancient CO2 and O2 evolution. Our results demonstrate that atmospheric O2 level at steady state is affected by CO2 input flux from Earth's interior via changes in biogeochemical cycles, but its response is modulated by several internal factors such as shelf area and POM sinking rate. We also found that early Paleozoic atmospheric O2 levels before the advent of land plant would be determined so that oceans may locate at the "edge of anoxia (EoA)" where the redox-dependency of marine P cycle plays a crucial role in regulating O2 cycle, and that POM sinking rate has a great impact on the EoA. Our findings provide insights into the O2 cycle over the Phanerozoic in response to the climatic and tectonic variations and

  19. Do Case Rates Affect Physicians' Clinical Practice in Radiation Oncology?: An Observational Study

    PubMed Central

    Loy, Bryan A.; Shkedy, Clive I.; Powell, Adam C.; Happe, Laura E.; Royalty, Julie A.; Miao, Michael T.; Smith, Gary L.; Long, James W.; Gupta, Amit K.

    2016-01-01

    Case rate payments combined with utilization monitoring may have the potential to improve the quality of care by reducing over and under-treatment. Thus, a national managed care organization introduced case rate payments at one multi-site radiation oncology provider while maintaining only fee-for-service payments at others. This study examined whether the introduction of the payment method had an effect on radiation fractions administered when compared to clinical guidelines. The number of fractions of radiation therapy delivered to patients with bone metastases, breast, lung, prostate, and skin cancer was assessed for concordance with clinical guidelines. The proportion of guideline-based care ascertained from the payer's claims database was compared before (2011) and after (2013) the payment method introduction using relative risks (RR). After the introduction of case rates, there were no significant changes in guideline-based care in breast, lung, and skin cancer; however, patients with bone metastases and prostate cancer were significantly more likely to have received guideline-based care (RR = 2.0 and 1.1, respectively, p<0.05). For the aggregate of all cancers, the under-treatment rate significantly declined (p = 0.008) from 4% to 0% after the introduction of case rate payments, while the over-treatment rate remained steady at 9%, with no significant change (p = 0.20). These findings suggest that the introduction of case rate payments did not adversely affect the rate of guideline-based care at the provider examined. Additional research is needed to isolate the effect of the payment model and assess implications in other populations. PMID:26870963

  20. Do Case Rates Affect Physicians' Clinical Practice in Radiation Oncology?: An Observational Study.

    PubMed

    Loy, Bryan A; Shkedy, Clive I; Powell, Adam C; Happe, Laura E; Royalty, Julie A; Miao, Michael T; Smith, Gary L; Long, James W; Gupta, Amit K

    2016-01-01

    Case rate payments combined with utilization monitoring may have the potential to improve the quality of care by reducing over and under-treatment. Thus, a national managed care organization introduced case rate payments at one multi-site radiation oncology provider while maintaining only fee-for-service payments at others. This study examined whether the introduction of the payment method had an effect on radiation fractions administered when compared to clinical guidelines. The number of fractions of radiation therapy delivered to patients with bone metastases, breast, lung, prostate, and skin cancer was assessed for concordance with clinical guidelines. The proportion of guideline-based care ascertained from the payer's claims database was compared before (2011) and after (2013) the payment method introduction using relative risks (RR). After the introduction of case rates, there were no significant changes in guideline-based care in breast, lung, and skin cancer; however, patients with bone metastases and prostate cancer were significantly more likely to have received guideline-based care (RR = 2.0 and 1.1, respectively, p<0.05). For the aggregate of all cancers, the under-treatment rate significantly declined (p = 0.008) from 4% to 0% after the introduction of case rate payments, while the over-treatment rate remained steady at 9%, with no significant change (p = 0.20). These findings suggest that the introduction of case rate payments did not adversely affect the rate of guideline-based care at the provider examined. Additional research is needed to isolate the effect of the payment model and assess implications in other populations.

  1. Anthropogenic Aerosol Radiative Forcing in Asia Derived From Regional Models With Atmospheric and Aerosol Data Assimilation

    SciTech Connect

    Chung, Chul Eddy; Ramanathan, V.; Carmichael, Gregory; Kulkarni, S.; Tang, Youhua; Adhikary, Bhupesh; Leung, Lai-Yung R.; Qian, Yun

    2010-07-05

    A high-resolution estimate of monthly 3D aerosol solar heating rates and surface solar fluxes in Asia from 2001 to 2004 is described here. This product stems from an Asian aerosol assimilation project, in which a) the PNNL regional model bounded by the NCEP reanalyses was used to provide meteorology, b) MODIS and AERONET data were integrated for aerosol observations, c) the Iowa aerosol/chemistry model STEM-2K1 used the PNNL meteorology and assimilated aerosol observations, and d) 3D (X-Y-Z) aerosol simulations from the STEM-2K1 were used in the Scripps Monte-Carlo Aerosol Cloud Radiation (MACR) model to produce total and anthropogenic aerosol direct solar forcing for average cloudy skies. The MACR model and STEM both used the PNNL model resolution of 0.45º×0.4º in the horizontal and of 23 layers in the troposphere. The 2001–2004 averaged anthropogenic all-sky aerosol forcing is -1.3 Wm-2 (TOA), +7.3 Wm-2 (atmosphere) and -8.6 Wm-2 (surface) averaged in Asia (60-138°E & Eq. -45°N). In the absence of AERONET SSA assimilation, absorbing aerosol concentration (especially BC aerosol) is much smaller, giving -2.3 Wm-2 (TOA), +4.5 Wm-2 (atmosphere) and -6.8 Wm-2 (surface), averaged in Asia. In the vertical, monthly forcing is mainly concentrated below 600hPa with maxima around 800hPa. Seasonally, low-level forcing is far larger in dry season than in wet season in South Asia, whereas the wet season forcing exceeds the dry season forcing in East Asia. The anthropogenic forcing in the present study is similar to that in Chung et al.’s [2005] in overall magnitude but the former offers fine-scale features and simulated vertical profiles. The interannual variability of the computed anthropogenic forcing is significant and extremely large over major emission outflow areas. In view of this, the present study’s estimate is within the implicated range of the 1999 INDOEX result. However, NCAR/CCSM3

  2. Climate Science for a Sustainable Energy Future Atmospheric Radiation Measurement Best Estimate (CSSEFARMBE)