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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 Radiative Transfer

    NASA Astrophysics Data System (ADS)

    Perliski, Lori

    Because radiative transfer cuts across many scientific disciplines with applications including remote sensing, climate, atmospheric chemistry, and photobiology, there is a need for comprehensive books on this subject that can appeal to a wide readership. While Atmospheric Radiative Transfer takes strides toward filling this niche by addressing a broad range of topics, it is dry reading and suffers from lack of detail. The book was based on a graduate-level course taught at the University of Sciences and Technologies in Lille, France, and indeed, the text reads much like an expanded outline perhaps derived from lecture notes.Part one deals with general radiative transfer, and part two covers Earth's radiation budget, the climate system, and remote sensing techniques. The radiative transfer equation and solutions for absorbing and scattering atmospheres are discussed as are the details of absorption, such as energy levels, line strengths, line intensities, equivalent widths, and weak- and strong-line limits.

  3. 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.

  4. 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.

  5. Martian atmospheric radiation budget

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1994-01-01

    A computer model is used to study the radiative transfer of the martian winter-polar atmosphere. Solar heating at winter-polar latitudes is provided predominately by dust. For normal, low-dust conditions, CO2 provides almost as much heating as dust. Most heating by CO2 in the winter polar atmosphere is provided by the 2.7 micron band between 10 km and 30 km altitude, and by the 2.0 micron band below 10 km. The weak 1.3 micron band provides some significant heating near the surface. The minor CO2 bands at 1.4, 1.6, 4.8 and 5.2 micron are all optically thin, and produce negligible heating. O3 provides less than 10 percent of the total heating. Atmospheric cooling is predominantly thermal emission by dust, although CO2 15 micron band emission is important above 20 km altitude.

  6. Atmospheric effects on radiation measurements

    NASA Technical Reports Server (NTRS)

    Jurica, G. M.

    1973-01-01

    Two essentially distinct regions of the electromagnetic spectrum are discussed: (1) the scattering region in which the radiation energy is provided by the incident solar flux; and (2) the infrared region in which emission by the earth's surface and atmospheric gases supply radiative energy. In each of these spectral regions the atmosphere performs its dual function with respect to a remote sensing measurement of surface properties. The atmosphere acts both as a filter and as a noise generator removing and obscuring sought after information. Nevertheless, with proper application of concepts such as have been considered, it will be possible to remove these unwanted atmospheric effects and to improve identification techniques being developed.

  7. How life affects the atmosphere

    NASA Technical Reports Server (NTRS)

    Walker, J. C.

    1984-01-01

    The impact of life on the atmosphere is examined through a discussion of the budgets of important atmospheric constituents and the processes that control their concentrations. Life profoundly influences oxygen and a number of minor atmospheric constituents, but many important gases, including those with the greatest effect on global climate, appear to be little altered by biological processes, at least in the steady state.

  8. 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

  9. 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.

  10. 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.

  11. Radiative transfer in spherical atmospheres

    NASA Technical Reports Server (NTRS)

    Kalkofen, W.; Wehrse, R.

    1984-01-01

    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.

  12. Radiative transfer of visible radiation in turbid atmosphere

    NASA Technical Reports Server (NTRS)

    Yamamoto, G.; Tanaka, M.

    1974-01-01

    Methods are presented for solving radiative transfer problems; they include the doubling method and the closely related matrix method, iterative method, Chandrasekhar's method of discrete ordinates, and Monte Carlo method. To consider radiation transport through turbid atmosphere, an atmospheric model was developed characterizing aerosols by parameters. Intensity and polarization of radiation in turbid atmospheres is discussed, as well as lower atmospheric heating due to solar radiation absorption by aerosols.

  13. 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.

  14. 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.

  15. Jupiter's radiation belts and atmosphere

    NASA Technical Reports Server (NTRS)

    De Pater, I.; Dames, H. A. C.

    1979-01-01

    Maps and stripscans of the radio emission from Jupiter were made during the Pioneer 10 flyby in December 1973 at wavelengths of 6 cm, 21 cm, and 50 cm using the Westerbork telescope in the Netherlands. With this instrument the disk of the planet was resolved at 6 and 21 cm. The pictures are averaged over 15 deg of Jovian longitude. At 21 cm the stripscans clearly show the existence of a 'hot region' in the radiation belts at a System III longitude (1965.0) of 255 + or - 10 deg. Its flux is about 9% of the total nonthermal flux, and it has a volume emissivity enhanced by a factor of about 1.6 with respect to the general radiation belts. The temperature of the thermal disk at 21 cm appears to be 290 + or - 20 K. This is likely due to a high ammonia mixing ratio in the atmosphere, a factor of 4-5 larger than the expected solar value of 0.00015.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. Radiative equilibrium and escape of Pluto's atmosphere

    NASA Astrophysics Data System (ADS)

    Erwin, Justin; Koskinen, Tommi T.; Yelle, Roger V.

    2015-11-01

    Observations of Pluto’s extend atmosphere by the New Horizons spacecraft motivate an update to our modeling effort on Pluto’s atmosphere. New Horizons observations have already improved our constraints on planet radius and surface pressure, which are key to modeling the atmospheric structure. We model the radiative conductive equilibrium in the lower atmosphere combined with the UV driven escape model of the upper atmosphere. The non-LTE radiative transfer model in the lower atmosphere include heating and cooling by CH4, CO, and HCN. The escape model of the upper atmosphere is updated to include diffusion and escape of each molecular component. These results will be used to aid in the analysis and better understanding of the full atmospheric structure.

  1. 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.

  2. 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.

  3. Radiation environment models and the atmospheric cutoff

    NASA Technical Reports Server (NTRS)

    Konradi, Andrei; Hardy, Alva C.; Atwell, William

    1987-01-01

    The limitations of radiation environment models are examined by applying the model to the South Atlantic anomaly (SAA). The local magnetic-field-intensity (in gauss) and McIlwain (1961) drift-shell-parameter contours in the SAA are analyzed. It is noted that it is necessary to decouple the atmospheric absorption effects from the trapped radiation models in order to obtain accurate radiation dose predictions. Two methods for obtaining more accurate results are proposed.

  4. 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.

  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. 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.

  12. Does Changing Atmospheric Model Resolution Affect Atmospheric Feedbacks?

    NASA Astrophysics Data System (ADS)

    Tett, S. F.; Wehner, M. F.; Stone, D. A.

    2014-12-01

    Simulations of the Community Atmosphere Model version 5.1 (CAM5.1) at horizontal resolutions of approximately 2, 1 and 0.25 degrees driven with climatological sea surface temperatures (SST) and 1990 forcings were carried out. The 1 and 2 degree CAM5.1 configurations used the default parameter values with the 0.25 degree CAM5.1 using the 1 degree configuration except the physics timestep being halved. Perturbed experiments, using CAM5.1, in which either SST is uniformly increased by 2K or CO2 doubled werealso carried out using the same configurations. A ``Cess'' type feedback analysis (twice change in 2xCO2/change in 2K simulations) was used to diagnose a ``Cess'' sensitivity. This sensitivity increased slightly with resolution due to changes in both the response to the uniform SST increase and to doubling CO2. This appears to arise from differing changes in tropical cloudsas resolution increases. Our results suggest that uncertainty in climate sensitivity is not strongly impacted by changing horizontal resolution up to 25 km. Thus, uncertainty in parameterisation likely remain the leading source of uncertainty in climate sensitivity.

  13. Radiative impact of atmospheric aerosols and clouds

    NASA Astrophysics Data System (ADS)

    Wong, Jeff

    1998-11-01

    The effect of aerosols and clouds on Earth's shortwave radiation budget is studied in this thesis. An expression for the global annual mean radiative forcing due to sulfate aerosols is extended for absorbing aerosols using a two-stream approximation. This expression depends on the backscattering fraction of the aerosol which varies with the effective radius of the aerosol size distribution. This variation leads to a factor of 2.0 variation in the radiative forcing of slightly absorbing aerosols. Water vapor condenses onto hygroscopic aerosols which results in a change in size and a change in the concentration of the chemical components of the aerosol. The original Köhler equation accurately describes the equilibrium size of a hygroscopic aerosol. Use of the modified Köhler equation leads to errors due to its thermodynamically inconsistent nature. On a global annual average, the direct radiative forcing of hygroscopic sulfate aerosol is -0.69 W m-2. Over highly polluted regions, the local radiative forcing can be as high as -7 W m-2 which is comparable to the forcing due to increased greenhouse gas concentrations. Using a plane-parallel model, an analytical expression is derived for the cloud radiative forcing ratio which is used as a measure of enhanced shortwave radiation absorption of clouds. With this model, high values of this ratio can be achieved by thick clouds with absorptances of approximately 0.3. High values of the ratio can also be obtained with low level clouds if the transmittance of the atmosphere above the cloud is reduced to approximately 0.8. This can be achieved by a high concentration of strongly absorbing aerosols.

  14. 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. PMID:11537397

  15. Planetary Atmosphere Dynamics and Radiative Transfer

    NASA Technical Reports Server (NTRS)

    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

  16. 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.

  17. The Impact of Atmospheric Aerosols on the Fraction of absorbed Photosynthetically Active Radiation

    NASA Astrophysics Data System (ADS)

    Veroustraete, Frank

    2010-05-01

    Aerosol pollution attracts a growing interest from atmospheric scientists with regard to their impact on health, the global climate and vegetation stress. A hypothesis, less investigated, is whether atmospheric aerosol interactions in the solar radiation field affect the amount of radiation absorbed by vegetation canopies and hence terrestrial vegetation productivity. Typically, aerosols affect vegetation canopy radiation absorption efficiency by altering the physical characteristics of solar radiation incoming on for example a forest canopy. It has been illustrated, that increasing mixing ratio's of atmospheric particulate matter lead to a higher fraction of diffuse sunlight as opposed to direct sunlight. It can be demonstrated, based on the application of atmospheric (MODTRAN) and leaf/canopy radiative transfer (LIBERTY/SPRINT) models, that radiation absorption efficiency in the PAR band of Picea like forests increases with increasing levels of diffuse radiation. It can be documented - on a theoretical basis - as well, that increasing aerosol loads in the atmosphere, induce and increased canopy PAR absorption efficiency. In this paper it is suggested, that atmospheric aerosols have to be taken into account when estimating vegetation gross primary productivity (GPP). The results suggest that Northern hemisphere vegetation CO2 uptake magnitude may increase with increasing atmospheric aerosol loads. Many climate impact scenario's related to vegetation productivity estimates, do not take this phenomenon into account. Boldly speaking, the results suggest a larger sink function for terrestrial vegetation than generally accepted. Keywords: Aerosols, vegetation, fAPAR, CO2 uptake, diffuse radiation.

  18. 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

  19. 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.

  20. 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.

  1. Radiation Belt Electron Dynamics: Modeling Atmospheric Losses

    NASA Technical Reports Server (NTRS)

    Selesnick, R. S.

    2003-01-01

    The first year of work on this project has been completed. This report provides a summary of the progress made and the plan for the coming year. Also included with this report is a preprint of an article that was accepted for publication in Journal of Geophysical Research and describes in detail most of the results from the first year of effort. The goal for the first year was to develop a radiation belt electron model for fitting to data from the SAMPEX and Polar satellites that would provide an empirical description of the electron losses into the upper atmosphere. This was largely accomplished according to the original plan (with one exception being that, for reasons described below, the inclusion of the loss cone electrons in the model was deferred). The main concerns at the start were to accurately represent the balance between pitch angle diffusion and eastward drift that determines the dominant features of the low altitude data, and then to accurately convert the model into simulated data based on the characteristics of the particular electron detectors. Considerable effort was devoted to achieving these ends. Once the model was providing accurate results it was applied to data sets selected from appropriate periods in 1997, 1998, and 1999. For each interval of -30 to 60 days, the model parameters were calculated daily, thus providing good short and long term temporal resolution, and for a range of radial locations from L = 2.7 to 3.9. .

  2. The wavelength dependence of Martian atmospheric dust radiative properties

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.; Ockert-Bell, M. E.; Arvidson, R.; Shepard, M.

    1993-01-01

    One of the key radiative agents in the atmosphere of Mars is the suspended dust particles. A new analysis of two data sets of the Martian atmosphere is being carried out in order to better evaluate the radiative properties of the atmospheric dust particles. The properties of interest are the size distribution, optical constants, and other radiative properties, such as the single-scattering albedo and phase function. Of prime importance is the wavelength dependence of these radiative properties throughout the visible and near-infrared wavelengths. Understanding the wavelength dependence of absorption and scattering characteristics will provide a good definition of the influence that the atmospheric dust has on heating of the atmosphere.

  3. 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

  4. The Skylab concentrated atmospheric radiation project. [Arizona and New Mexico

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.; Whitehead, V. S.; Marlatt, W. E.

    1975-01-01

    The Skylab field phase in June, August and September of 1973 for the Skylab concentrated atmospheric radiation project provided an opportunity to conduct infrared and solar observations and subsequent calculations beneath the orbiting space vehicle during EREP overpasses. Infrared and solar transmission and absorption properties observed within the atmosphere were compared with EREP experiments, notably the S-191 and S-192. These same observations were later employed in the development and comparison of various atmospheric infrared and solar radiative transfer approximations. Solar radiation observations and calculations in the scattering atmosphere included the 0.4 to 1.1 microns spectral range while infrared observations and calculations covered the spectral band and portions thereof within the 5.0 to 40.0 microns region. Principal conclusions drawn from the solar radiation research and the infrared radiation research are discussed.

  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. 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.

  8. 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.

  9. UV RADIATION MEASUREMENTS/ATMOSPHERIC CHARACTERIZATION

    EPA Science Inventory

    Because exposure to ultraviolet (UV) radiation is an ecosystem stressor and poses a human health risk, the National Exposure Research Laboratory (NERL) has undertaken a research program to measure the intensity of UV-B radiation at various locations throughout the U.S. In Septem...

  10. 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

  11. On the Effect of Heavy Aerosols Loads on Longwave Atmospheric Radiation, Theoretical Investigations

    NASA Astrophysics Data System (ADS)

    Maghrabi, Abdullrahman

    2014-05-01

    Dust particles affect both solar and terrestrial radiation by scattering and absorption and are therefore considered to be a significant climate-forcing factor. In this study, theoretical simulations were carried out using MODTRAN program to examine the changes in the atmospheric radiation (4- 100 μm) during dust storms occurred over Riyadah, central Saudi Arabia, between 1999-2000 . The Atmospheric Optical Depth (AOD) measurements at (500 nm) and meteorological parameters were used as an input into MODTRAN. The simulation results showed that the heavy aerosol loads brought by the dust storms increase the atmospheric emission in the atmospheric window (8-14 μm) such that the window emissions resembled those of a blackbody and the atmospheric window was almost closed.

  12. A radiative model for Titan's atmosphere in the IR

    NASA Astrophysics Data System (ADS)

    Cofano, A.; Sindoni, G.

    2015-10-01

    The aim of this work is the development of a model of Titan atmosphere between 1 and 5 micron, using data from Cassini-Huygens mission. The simulations will be useful to remove the atmospheric features from the measured spectrum, to study the surface. The radiative transfer model is performed with ARS (Atmosphere Radiation Spectrum), a a group of Fortran 77 routines, able to calculate absorption coefficients, radiance and other parameters about gas and aerosols at LTE (Local Thermal Equilibrium) [5] and considering multiple scattering in nadir geometry. Our study covers the IR spectral range but it would be extended also to the visible spectrum.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. Radiation Transport in the Atmosphere - Sea Ice - Ocean System.

    NASA Astrophysics Data System (ADS)

    Jin, Zhonghai

    1995-01-01

    A comprehensive radiative transfer model for the coupled atmosphere-sea ice-ocean system has been developed. The theoretical work required for constructing such a coupled model is described first. This work extends the discrete ordinate method, which has been proven to be effective in studies of radiative transfer in the atmosphere, to solve the radiative transfer problem pertaining to a system consisting of two strata with different indices of refraction, such as the atmosphere-ocean system and the atmosphere -sea ice-ocean system. The relevant changes (as compared to the standard problem with 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 presented. This solution is then applied to the atmosphere -sea ice-ocean system to study the solar energy balance in this coupled system. The input parameters required by the model are observable physical properties (e.g., the profiles of temperature and gas concentrations in the atmosphere, and the profiles of temperature, density, and salinity in the ice). The atmosphere, sea ice and ocean are each divided into a sufficient number of layers in the vertical to adequately resolve changes in their optical properties. This model rigorously accounts for the multiple scattering and absorption by atmospheric molecules, clouds, snow and sea water, as well as inclusions in the sea ice, such as brine pockets and air bubbles. The effects of various factors on the solar energy distribution in the entire system have been studied quantitatively. These factors include the ice salinity and density variations, cloud microphysics as well as variations in melt ponds and snow cover on the ice surface. Finally, the coupled radiative transfer model is used to study the impacts of clouds, snow and ice algae on the light transport in sea ice and in the ocean, as well as to simulate spectral irradiance and

  3. 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

  4. A New Perspective on Trapped Radiation Belts in Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Diaz, A.; Lodhi, M. A. K.; Wilson, T. L.

    2005-01-01

    The charged particle fluxes trapped in the magnetic dipole fields of certain planets in our Solar System are interesting signatures of planetary properties in space physics. They also represent a source of potentially hazardous radiation to spacecraft during planetary and interplanetary exploration. The Earth s trapped radiation belts have been studied for years and the physical mechanisms by which primary radiation from the Sun and Galaxy is captured is well understood. The higher-energy particles collide with molecules in the planetary atmosphere and initiate large cascades of secondary radiation which itself becomes trapped by the magnetic dipole field of the planet. Some of it is even backscattered as albedo neutrons.

  5. 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.

  6. Atmospheric Radiation Measurement Program Facilities Newsletter - September 1999

    SciTech Connect

    Holdridge, D. J., ed

    1999-09-27

    The Atmospheric Radiation Measurement Program September 1999 Facilities Newsletter discusses the several Intensive Observation Periods (IOPs) that the ARM SGP CART site will host in the near future. Two projects of note are the International Pyrgeometer Intercomparison and the Fall Single Column Model (SCM)/Nocturnal Boundary Layer (NBL) IOP. Both projects will bring many US and international scientists to the SGP CART site to participate in atmospheric research.

  7. Studies of radiative transfer in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Irvine, W. M.; Schloerb, F. P.

    1984-01-01

    Progress is reported in modeling cometary emission in the 18-cm OH transition with specific application and predictions for Comet Halley. Radiative transfer is also being studied in rough and porous media. The kinematics of the cold, dark interstellar cloud Li34N were examined, and CO monitoring of Venus and Mars continues. Analysis of 3.4 mm maps of the lunar surface shows thermal anomalies associated with such surface features as the Crater Copernicus, Mare Imbrium, Mare Nubium, Mare Serenitatis, and Mare Tranquillatis.

  8. 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.

  9. Radiative Heat Transfer During Atmosphere Entry at Parabolic Velocity

    NASA Technical Reports Server (NTRS)

    Yoshikawa, Kenneth K.; Wick, Bradford H.

    1961-01-01

    Stagnation point radiative heating rates for manned vehicles entering the earth's atmosphere at parabolic velocity are presented and compared with corresponding laminar convective heating rates. The calculations were made for both nonlifting and lifting entry trajectories for vehicles of varying nose radius, weight-to-area ratio, and drag. It is concluded from the results presented that radiative heating will be important for the entry conditions considered.

  10. Parameterization of Radiative Processes in Vertically Nonhomogeneous Multiple Scattering Atmospheres.

    NASA Astrophysics Data System (ADS)

    Fu, Qiang

    1991-02-01

    A radiation model has been developed to calculate the radiative fluxes and heating rates in plane parallel, vertically nonhomogeneous, multiple scattering atmospheres with an accuracy of better than 5%. This scheme is appropriate for use in climate and numerical prediction models to study the effect of cloud and radiation interactions. Parameterization of nongray gaseous absorption in vertically nonhomogeneous atmospheres has been developed based upon the correlated K-distribution method. The entire radiation spectrum is divided into 18 intervals: 6 in the solar and 12 in the infrared. By using a minimum number of quadrature points within each wavelength interval to represent the gaseous absorption and to treat overlap, we need to perform 121 spectral calculations for each vertical profile to obtain total radiative fluxes and heating rates. The treatment of gaseous absorption introduces errors less than 0.05 K/day in the heating rates below 30 km and and relative errors less than 0.5% in the fluxes. The single-scattering properties of water/ice clouds have been parameterized in terms of the effective size and liquid/ice water contents, based on Mie-scattering/ray -tracing computations with the best available size distributions. The parameterization gives an accuracy within about 1% in the solar and 5% in the infrared. By using the delta-four-stream approximation, a single algorithm has been developed for radiative transfer calculations. For vertically nonhomogeneous atmospheres, this code is numerically stable and computationally efficient. The accuracy of the algorithm is generally better than 5%, but it can produce more accurate results in the limit of no scattering. Compared with line-by-line results from clear -sky longwave calculations when all constituents were included, the errors in heating rates calculated by the new radiation model are less than 0.1 K/day in the troposphere and lower stratosphere. The errors in radiative fluxes are less than 1% both at

  11. 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

  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. Radiative cooling profiles of the Jovian-planet atmospheres in radiative-convective equilibrium

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Hashimoto, G.; Ishiwatari, M.; Takahashi, Y.; Onishi, M.; Kuramoto, K.

    2014-04-01

    In order to understand cloud convection in the Jovian-planet atmospheres, we have estimated the radiative cooling profiles with a newly developed numerical model. This model computes a radiativeconvective equilibrium state of atmosphere with given potential temperature and composition of deep atmosphere. The modeled outgoing thermal radiation and tropopause level are found to be little dependent on deep H2O abundance. From the modeled radiative cooling profile as well as the extent of wet convection zone, one can derive the temporal interval of tall cumulonimbus activity by equating the amount of radiative cooling and latent heat release associated with vapor condensation. The estimated interval increases with deep H2O abundance. Prolonged intervals of large scale cloud features appeared on Jupiter and Saturn imply enrichment of H2O in their deep atmosphere relative to the solar proportion, consistent with the estimation range from studies of internal structure modeling.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Astrophysics Data System (ADS)

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

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

  17. 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.

  18. Comparision of algorithms for incoming atmospheric long-wave radiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While numerous algorithms exist for predicting incident atmospheric long-wave radiation under clear (Lclr) and cloudy skies, only a handful of comparisons have been published to assess the accuracy of the different algorithms. Virtually no comparisons have been made for both clear and cloudy skies ...

  19. 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.

  20. 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.

  1. Studies of radiative transfer in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Irvine, W. M.; Schloerb, F. P.

    1986-01-01

    Schloerb and Claussen continued their analysis of the very high quality data set obtained on the 18 centimeter OH line from the Comet P/Halley with the NRAO 43 meter antenna. The high spectral resolution (0.22 km/sec) and high signal-to-noise of the OH spectra make them ideal for the study of kinematics in the coma. Synthetic profiles were initiated for comparison with the data. A vectorial model was developed using the Monte Carlo techniques originated by Combi and Delsemme. Analysis of the millimeter wavelength observations of HCN emission from P/Halley obtained throughout much of the recent apparition were continued using the University of Massachusetts 14 millimeter-wavelength (FCRAO) antenna. A detailed analysis of the HCN lineshpaes was performed over the last six months. The excitation of HCN in the coma was studied to obtain a detailed match to the observed spectra. The passive millimeter wave radiometer was used to probe the physical and chemical nature of comets from spacecraft. Work was continued on an improved theory of radiative transfer for rough and porous surfaces, such as the regoliths of satellites, asteroids, and comets.

  2. 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.

  3. 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

  4. 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.

  5. Surface shortwave aerosol radiative forcing during the Atmospheric Radiation Measurement Mobile Facility deployment in Niamey, Niger

    NASA Astrophysics Data System (ADS)

    McFarlane, S. A.; Kassianov, E. I.; Barnard, J.; Flynn, C.; Ackerman, T. P.

    2009-07-01

    The Atmospheric Radiation Measurement (ARM) Program's Mobile Facility (AMF) was deployed to Niamey, Niger, during 2006. Niamey, which is located in sub-Saharan Africa, is affected by both dust and biomass burning emissions. Column aerosol optical properties were derived from multifilter rotating shadowband radiometer, measurements and the vertical distribution of aerosol extinction was derived from a micropulse lidar during the two observed dry seasons (January-April and October-December). Mean aerosol optical depth (AOD) and single scattering albedo (SSA) at 500 nm during January-April were 0.53 ± 0.4 and 0.94 ± 0.05, while during October-December mean AOD and SSA were 0.33 ± 0.25 and 0.99 ± 0.01. Aerosol extinction profiles peaked near 500 m during the January-April period and near 100 m during the October-December period. Broadband shortwave surface fluxes and heating rate profiles were calculated using retrieved aerosol properties. Comparisons for noncloudy periods indicated that the remote sensing retrievals provided a reasonable estimation of the aerosol optical properties, with mean differences between calculated and observed fluxes of less than 5 W m-2 and RMS differences less than 25 W m-2. Sensitivity tests showed that the observed fluxes could be matched with variations of <10% in the inputs to the radiative transfer model. The calculated 24-h averaged SW instantaneous surface aerosol radiative forcing (ARF) was -21.1 ± 14.3 W m-2 and was estimated to account for 80% of the total radiative forcing at the surface. The ARF was larger during January-April (-28.5 ± 13.5 W m-2) than October-December (-11.9 ± 8.9 W m-2).

  6. Energy deposition of corpuscular radiation in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Kudela, K.

    1989-01-01

    Main components of corpuscular radiation contributing to energy deposition (ED in eV/cu cm/s) in the atmosphere (10 to 100 km) are cosmic ray nuclei (CR - galactic and solar) and high energy electrons (HEE), mainly of magnetospheric origin. Galactic CR depending on solar cycle phase and latitude are dominant source of ED by corpuscular radiation below 50 to 60 km. Below 20 km secondaries must be assumed. More accurate treatment need assuming of individual HE solar flare particles, cut off rigidities in geomagnetic field and their changes during magnetospheric disturbances. Electrons E sub e greater than 30 keV of magnetospheric origin penetrating to atmosphere contribute to production rate below 100 km especially on night side. High temporal variability, local time dependence and complicated energy spectra lead to complicated structure of electron ED rate. Electrons of MeV energy found at geostationary orbit, pronouncing relation to solar and geomagnetic activity, cause maximum ED at 40 to 60 km. Monitoring the global distribution of ED by corpuscular radiation in middle atmosphere need continuing low altitude satellite measurements of both HEE and x ray BS from atmosphere as well as measurements of energy spectra and charge composition of HE solar flare particles.

  7. 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.

  8. 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.

  9. Atmospheric transport, clouds and the Arctic longwave radiation paradox

    NASA Astrophysics Data System (ADS)

    Sedlar, Joseph

    2016-04-01

    Clouds interact with radiation, causing variations in the amount of electromagnetic energy reaching the Earth's surface, or escaping the climate system to space. While globally clouds lead to an overall cooling radiative effect at the surface, over the Arctic, where annual cloud fractions are high, the surface cloud radiative effect generally results in a warming. The additional energy input from absorption and re-emission of longwave radiation by the clouds to the surface can have a profound effect on the sea ice state. Anomalous atmospheric transport of heat and moisture into the Arctic, promoting cloud formation and enhancing surface longwave radiation anomalies, has been identified as an important mechanism in preconditioning Arctic sea ice for melt. Longwave radiation is emitted equally in all directions, and changes in the atmospheric infrared emission temperature and emissivity associated with advection of heat and moisture over the Arctic should correspondingly lead to an anomalous signal in longwave radiation at the top of the atmosphere (TOA). To examine the role of atmospheric heat and moisture transport into the Arctic on TOA longwave radiation, infrared satellite sounder observations from AIRS during 2003-2014 are analyzed for summer (JJAS). Thermodynamic metrics are developed to identify months characterized by a high frequency of warm and moist advection into the Arctic, and segregate the 2003-14 time period into climatological and anomalously warm, moist summer months. We find that anomalously warm, moist months result in a significant TOA longwave radiative cooling, which is opposite the forcing signal that the surface experiences during these months. At the timescale of the advective events, 3-10 days, the TOA cooling can be as large as the net surface energy budget during summer. When averaged on the monthly time scale, and over the full Arctic basin (poleward of 75°N), summer months experiencing frequent warm, moist advection events are

  10. 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.

  11. 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.

  12. Parameterization of radiative processes in vertically nonhomogeneous multiple scattering atmospheres

    NASA Astrophysics Data System (ADS)

    Fu, Qiang

    1991-05-01

    A radiation model has been developed to calculate the radiative fluxes and heating rates in plane parallel, vertically nonhomogeneous, multiple scattering atmospheres with an accuracy of better than 5 percent. This scheme is appropriate for use in climate and numerical prediction models to study the effect of cloud and radiation interactions. Parameterization of nongray gaseous absorption in vertically nonhomogeneous atmospheres has been developed based upon the correlated K-distribution method. The entire radiation spectrum is divided into 18 intervals: 6 in the solar and 12 in the infrared. By using a minimum number of quadrature points within each wavelength interval to represent the gaseous absorption and to treat overlap, we need to perform 121 spectral calculations for each vertical profile to obtain total radiative fluxes and heating rates. The treatment of gaseous absorption introduces errors less than 0.05 K/day in the heating rates below 30 km and relative errors less than 0.5 percent in the fluxes. The single-scattering properties of water/ice clouds have been parameterized in terms of the effective size and liquid/ice water contents, based on Mie-scattering/ray-tracing computations with the best available size distributions. The parameterization gives an accuracy within about 1 percent in the solar and 5 percent in the infrared. By using the delta-four-stream approximation, a single algorithm has been developed for radiative transfer calculations. For vertically nonhomogeneous atmospheres, this code is numerically stable and computationally efficient. The accuracy of the algorithm is generally better than 5 percent, but it can produce more accurate results in the limit of no scattering. Compared with line-by-line results from clear-sky longwave calculations when all constituents were included, the errors in heating rates calculated by the new radiation model are less than 0.1 K/day in the troposphere and lower stratosphere. The errors in radiative

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. Atmospheric scattering and decay of inner radiation belt electrons

    NASA Astrophysics Data System (ADS)

    Selesnick, R. S.

    2012-08-01

    The dynamics of inner radiation belt electrons are governed by competing source, loss, and transport processes. However, during the recent extended solar minimum period the source was inactive and electron intensity was characterized by steady decay. This provided an opportunity to determine contributions to the decay rate of losses by precipitation into the atmosphere and of diffusive radial transport. To this end, a stochastic simulation of inner radiation belt electron transport is compared to data taken by the IDP instrument on the DEMETER satellite during 2009. For quasi-trapped, 200 keV electrons atL= 1.3, observed in the drift loss cone (DLC), results are consistent with electron precipitation losses by atmospheric scattering alone, provided account is taken of non-diffusive wide-angle scattering. Such scattering is included in the stochastic simulation using a Markov jump process. Diffusive small-angle atmospheric scattering, while causing most of the precipitation losses, is too slow relative to azimuthal drift to contribute significantly to DLC intensity. Similarly there is no contribution from scattering by VLF plasma waves. Energy loss, energy diffusion, and azimuthal drift are also included in the model. Even so, observed decay rates of stably-trapped electrons withL < 1.5 are slower than predicted by scattering losses alone, requiring radial diffusion with coefficient DLL ˜ 3 × 10-10 s-1 to replenish electrons lost to the atmosphere at low L values.

  20. 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.

  1. Preliminary design for Arctic atmospheric radiative transfer experiments

    SciTech Connect

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

    1995-04-01

    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.

  2. Nonequilibrium radiative heating during outer planet atmospheric entry

    NASA Technical Reports Server (NTRS)

    Nelson, H. F.

    1983-01-01

    The contradictory results obtained by investigators assessing the influence of finite-rate ionization on the radiative heating of probes entering the atmospheres of Jupiter and Saturn are discussed. Tiwari and Szema (1979) found that the radiation heating increased, whereas Leibowitz (1973) and Liebowitz and Kuo (1976) found that it decreased in relation to the results obtained when the ionization rate was assumed to be in equilibrium at the local thermodynamic conditions. The study presented here is limited to stagnation shock layers for nonviscous, hydrogen-helium plasmas with cold, nonblowing conditions at the probe heat shield. It is found that the radiative heating comes mainly from the Balmer region of the spectrum, where the shock layer is optically thin.

  3. Atmospheric Ionizing Radiation (AIR) ER-2 Preflight Analysis

    NASA Technical Reports Server (NTRS)

    Tai, Hsiang; Wilson, John W.; Maiden, D. L.

    1998-01-01

    Atmospheric ionizing radiation (AIR) produces chemically active radicals in biological tissues that alter the cell function or result in cell death. The AIR ER-2 flight measurements will enable scientists to study the radiation risk associated with the high-altitude operation of a commercial supersonic transport. The ER-2 radiation measurement flights will follow predetermined, carefully chosen courses to provide an appropriate database matrix which will enable the evaluation of predictive modeling techniques. Explicit scientific results such as dose rate, dose equivalent rate, magnetic cutoff, neutron flux, and air ionization rate associated with those flights are predicted by using the AIR model. Through these flight experiments, we will further increase our knowledge and understanding of the AIR environment and our ability to assess the risk from the associated hazard.

  4. 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.

  5. 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.

  6. Radiative constraints on the energy budget of the atmosphere

    NASA Astrophysics Data System (ADS)

    Minschwaner, Kenneth Robert

    An infrared radiative code has been developed and applied to studies of the steady state energy balance of the atmosphere. The model utilizes the correlated-k method to carry out spectral integrations and includes an improved treatment of the finite-difference approximation to the vertical radiative flux integral. Absorption coefficients are calculated directly from archived spectroscopic data. Radiative cooling rates computed with the model agree with benchmark line-by-line calculations to better than 5 percent; top of the atmosphere fluxes agree to within 1 percent. The sensitivity of clear-sky flux components to changes in sea surface temperature, atmospheric lapse rate, and relative humidity are examined. Comparison with satellite measurements indicates that a 6.5 K/km lapse rate model cannot reproduce observed infrared fluxes. Agreement is improved by employing a parameterization in which the static stability is related empirically to the surface temperature. Assumption of a constant profile of relative humidity yields results consistent with observations for surface temperatures less than 298 K, but comparison with measurements at higher temperatures suggests that significant increases in middle and upper tropospheric humidity must accompany warmer ocean temperatures. The enhanced greenhouse forcing at higher temperatures is felt primarily in the atmosphere, rather than at the surface. A simple one-dimensional model is presented to describe the energy budget of the tropical atmosphere. The heating of the tropical atmosphere due to deep cumulus convection is accounted for by clear-sky subsidence acting on a stable lapse rate of temperature. Results suggest that the strength of the subsidence field may be sensitive to changes in atmospheric composition, specifically variations in the altitude distribution of H2O and changes in the abundance of greenhouse gases such as CO2. Buoyancy considerations suggest that there may be an upper limit to the range of

  7. 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

  8. 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.

  9. Optical and radiative-transfer properties of mixed atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Degheidy, A. R.; Sallah, M.; Elgarayhi, A.; Shaaban, S. M.

    2015-04-01

    The optical and radiative-transfer properties of mixed atmospheric aerosols have been investigated. The aerosol medium is considered as a plane-parallel anisotropic scattering medium with diffusive reflecting boundaries and containing an internal radiation source. The basic components are defined by their complex refractive index, a lognormal size distribution and humidity dependence in hygroscopic particles. The aerosol particles are assumed to be spherical, so the scattering parameters in the form of single scattering albedo, asymmetry factor, scattering, absorption, extinction efficiencies and linear anisotropic coefficient are calculated using the Mie theory. The calculations have been performed for individual aerosol particles, internal and external mixing media. Radiation transfer problem through the considered aerosol medium has been solved in terms of the solution of the corresponding source-free problem with simple boundary conditions. For the solution of the source-free problem, the Variational Pomraning-Eddington technique has been employed. The variation of the radiative-transfer properties (partial radiative fluxes at the medium boundaries) have been calculated and represented graphically for the different aerosols with their different mixing states. A comparison of the obtained results versus available published data has been performed and a very good agreement was observed.

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

    NASA Astrophysics Data System (ADS)

    LaDelfe, Peter C.; Weber, Paul G.; Rodriguez, C. William

    1995-02-01

    The hemispherical optimized net radiometer (HONER) is an instrument under development at the Los Alamos National Laboratory as part of the Atmospheric Radiation measurements/Unmanned Aerospace Vehicles (ARM/UAV) program. HONER is a radiometer which will either measure directly the difference between the total upwelling and downwelling fluxes or the individual fluxes and will provide a means of measuring the atmospheric radiative flux divergence. Unlike existing instruments which only 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 the two relevant spectral bands; one covering the solar dominated region from less than 0.4 micrometer to approximately 4 micrometers and the other covering the region from approximately 4 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 describe the basic design and operation of the sensor head and the on-board reference sources as well as the means of the initial deployment on a UAV. This instrument can also be used in ground-based, space, or other airborne applications.

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    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.

  13. Thermal Structure and Radiative Balance of the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Limaye, S. S.

    2014-04-01

    Venus Express, observing since April 2006 has returned a wealth of useful information about the atmospheric temperature and density structure of the planet. New and refined instruments have advanced not only the accuracy but also the altitude range of the inferred structure. With multiple experiments on Venus Express contributing to the inferred vertical structure, there is overlap in some altitude regions, allowing and requiring conciliation of the inferred values in terms of spatial and temporal coverage as well as errors and biases. In addition, there are older spacecraft results as well as recent ground based observations that contribute to the new information about the thermal structure of the atmosphere. Regarding the radiative balance, we have new information about changes in the absorbed solar radiation over the duration of the Venus Express mission, but little new information in terms of the emitted radiation from the planet. A coordinated effort was initiated in late 2013 to assess these new data through an international team hosted by the International Space Studies Institute [1]. This solicited chapter for the Venus III book being developed at present [2] is based on the efforts of this group.

  14. Solar radiation in Saturn's atmosphere: maximum penetration and heating rates

    NASA Astrophysics Data System (ADS)

    Pérez-Hoyos, S.; Sánchez-Lavega, A.

    2005-08-01

    We use our previous long-term study (1994-2004) of Saturn's upper clouds and hazes vertical structure (Pérez-Hoyos et al., Icarus, 176, 155, 2005), to retrieve the internal fields and penetration levels of optical radiation in the atmosphere (wavelengths from 250 nm to 950 nm). We have used a doubling adding radiative transfer code and assumed different vertical cloud structure models, as bounded by our previous photometric analysis and other works. We analyze the levels between 1 mbar to 6 bar taking into account the seasonal and ring-shadowing effects on insolation. The main result is that the expected maximum penetration level of the visual radiation on the upper hazes along Saturn's year is ˜ 0.3 bar. Maps of the temporal and latitudinal distribution of the atmospheric heating rates are also presented. Our results provide realistic constraints on the available energy and vertical extent for general circulation -shallow- models for the giant planets based on the terrestrial circulation analogy. Acknowledgments: S.P.-H and A.S.-L. are supported by MCYT AYA2003-03216, fondos FEDER, and Grupos UPV 15946/2004. S.P.-H. acknowledges a PhD fellowship from the Spanish MEC.

  15. 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.

  16. 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.

  17. 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

  18. 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.

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

    DOEpatents

    Karl, Jr., Robert R.

    1990-01-01

    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.

  20. 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.

  1. Developing of a New Atmospheric Ionizing Radiation (AIR) Model

    NASA Technical Reports Server (NTRS)

    Clem, John M.; deAngelis, Giovanni; Goldhagen, Paul; Wilson, John W.

    2003-01-01

    As a result of the research leading to the 1998 AIR workshop and the subsequent analysis, the neutron issues posed by Foelsche et al. and further analyzed by Hajnal have been adequately resolved. We are now engaged in developing a new atmospheric ionizing radiation (AIR) model for use in epidemiological studies and air transportation safety assessment. A team was formed to examine a promising code using the basic FLUKA software but with modifications to allow multiple charged ion breakup effects. A limited dataset of the ER-2 measurements and other cosmic ray data will be used to evaluate the use of this code.

  2. 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.

  3. 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.

  4. 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).

  5. The Effects of Aerosol on Atmospheric UV Radiation: Measurements and Modeling from the MILAGRO Field Campaign

    NASA Astrophysics Data System (ADS)

    Madronich, S.; Hall, S.; Shetter, R.; Slusser, J.; Arnott, P.

    2007-05-01

    The MILAGRO field campaign took place in and near Mexico City 1-30 March 2006. A comprehensive data set was obtained on atmospheric chemical composition (gas and aerosol), aerosol microphysics, spectral radiation, and meteorology from surface-, aircraft-, and satellite-based instruments. For much of this time, the lower atmosphere was laden with large amounts of aerosols originating from urban and industrial sources, biomass fires, and wind-blown dust. Spectral radiation measurements are available from filter radiometers and spectroradiometers, and span ultraviolet (UV) wavelengths important to surface biota and tropospheric photochemistry. By combining the spectral radiation measurements, aerosol composition, optical, and microphysical measurements, and modeling, an assessment is now possible on how aerosols affect surface UV radiation (e.g. DNA damage, erythema, vitamin-D production) and vertical profiles of photolysis frequencies (e.g. JNO2, JO3(O1D), JCH2O, JHONO). Interactions between aerosol-scattered radiation and absorption by gaseous pollutants (esp. O3, SO2, and NO2) can also be evaluated. Implications for human health and photochemical oxidant formation will be discussed.

  6. Experimental Characterization of Radiation Forcing due to Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Sreenivas, K. R.; Singh, D. K.; Ponnulakshmi, V. K.; Subramanian, G.

    2011-11-01

    Micro-meteorological processes in the nocturnal atmospheric boundary layer (NBL) including the formation of radiation-fog and the development of inversion layers are controlled by heat transfer and the vertical temperature distribution close to the ground. In a recent study, it has been shown that the temperature profile close to the ground in stably-stratified, NBL is controlled by the radiative forcing due to suspended aerosols. Estimating aerosol forcing is also important in geo-engineering applications to evaluate the use of aerosols to mitigate greenhouse effects. Modeling capability in the above scenarios is limited by our knowledge of this forcing. Here, the design of an experimental setup is presented which can be used for evaluating the IR-radiation forcing on aerosols under either Rayleigh-Benard condition or under conditions corresponding to the NBL. We present results indicating the effect of surface emissivities of the top and bottom boundaries and the aerosol concentration on the temperature profiles. In order to understand the observed enhancement of the convection-threshold, we have determined the conduction-radiation time constant of an aerosol laden air layer. Our results help to explain observed temperature profiles in the NBL, the apparent stability of such profiles and indicate the need to account for the effect of aerosols in climatic/weather models.

  7. Cosmic ray decreases affect atmospheric aerosols and clouds

    NASA Astrophysics Data System (ADS)

    Svensmark, Henrik; Bondo, Torsten; Svensmark, Jacob

    2009-08-01

    Close passages of coronal mass ejections from the sun are signaled at the Earth's surface by Forbush decreases in cosmic ray counts. We find that low clouds contain less liquid water following Forbush decreases, and for the most influential events the liquid water in the oceanic atmosphere can diminish by as much as 7%. Cloud water content as gauged by the Special Sensor Microwave/Imager (SSM/I) reaches a minimum ≈7 days after the Forbush minimum in cosmic rays, and so does the fraction of low clouds seen by the Moderate Resolution Imaging Spectroradiometer (MODIS) and in the International Satellite Cloud Climate Project (ISCCP). Parallel observations by the aerosol robotic network AERONET reveal falls in the relative abundance of fine aerosol particles which, in normal circumstances, could have evolved into cloud condensation nuclei. Thus a link between the sun, cosmic rays, aerosols, and liquid-water clouds appears to exist on a global scale.

  8. 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.

  9. Radiative transfer code SHARM for atmospheric and terrestrial applications

    NASA Astrophysics Data System (ADS)

    Lyapustin, A. I.

    2005-12-01

    An overview of the publicly available radiative transfer Spherical Harmonics code (SHARM) is presented. SHARM is a rigorous code, as accurate as the Discrete Ordinate Radiative Transfer (DISORT) code, yet faster. It performs simultaneous calculations for different solar zenith angles, view zenith angles, and view azimuths and allows the user to make multiwavelength calculations in one run. The Δ-M method is implemented for calculations with highly anisotropic phase functions. Rayleigh scattering is automatically included as a function of wavelength, surface elevation, and the selected vertical profile of one of the standard atmospheric models. The current version of the SHARM code does not explicitly include atmospheric gaseous absorption, which should be provided by the user. The SHARM code has several built-in models of the bidirectional reflectance of land and wind-ruffled water surfaces that are most widely used in research and satellite data processing. A modification of the SHARM code with the built-in Mie algorithm designed for calculations with spherical aerosols is also described.

  10. 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. PMID:14727666

  11. Effects of atmospheric structure on radiative heating for Jupiter entry probe

    NASA Technical Reports Server (NTRS)

    Sutton, K.; Jones, J. J.; Powell, R. W.

    1978-01-01

    New estimates of the radiative heat load to a Jupiter entry probe have been obtained for revised models of Jupiter's atmosphere based on the latest data from Pioneer 10 and 11 missions and earth-based experiments. The new estimates of the radiative heat load are compared with results obtained for the previous atmospheric models. The changes in Jupiter's atmospheric models cause a substantial reduction in the radiative heat load for the atmosphere denoted as 'cool', but only moderate reductions for the atmospheres denoted as 'nominal' and 'warm'. Results are also presented showing the effects of inertial entry angle for off-equatorial entries in the revised model atmospheres.

  12. 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

  13. 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.

  14. How can secondary electron emission from dust affect Martian atmosphere?

    NASA Astrophysics Data System (ADS)

    Pavlu, Jiri; Safrankova, Jana; Nemecek, Zdenek; Beranek, Martin; Vaverka, Jakub; Richterova, Ivana

    2014-05-01

    Growing interest to Mars connected with recent and forthcoming missions led to numerous studies dealing with behavior of dust grains on the Martian surface and within its atmosphere. The present paper discusses electrical properties of a Martian soil simulant (JSC Mars-1) involving the dust charging experiment where a single dust grain is trapped and stored for a long time in a vacuum chamber and its emission characteristics, especially the secondary electron emission, are studied. The interaction of the grain with the intense electron beam showed the grain surface potential is generally low and determined by a mean atomic number of the grain material at a low-energy range (< 1 keV), whereas it can reach a limit of the field ion emission being irradiated by more energetic electrons. Experimental results are compared with numerical simulations showing a crucial influence of the grain shape and size in the range of higher (> 2 keV) electron energies. We further discuss possible implications of the secondary electron emission from dust grains for the generation of lightnings on Mars.

  15. Relationships among top-of-atmosphere radiation and atmospheric state variables in observations and CESM

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Zhang, Yongxin; Fasullo, John T.

    2015-10-01

    A detailed examination is made in both observations and the Community Earth System Model (CESM) of relationships among top-of-atmosphere radiation, water vapor, temperatures, and precipitation for 2000-2014 to assess the origins of radiative perturbations and climate feedbacks empirically. The 30-member large ensemble coupled runs are analyzed along with one run with specified sea surface temperatures for 1994 to 2005 (to avoid volcanic eruptions). 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 absorbed solar radiation (ASR) over the Southern Oceans and not enough in the tropics, and El Niño-Southern Oscillation (ENSO) is too large in amplitude in this version of the model. However, the covariability of monthly mean anomalies produces remarkably good replication of most of the observed relationships. 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. Over the Warm Pool in the tropical western Pacific and Indian Oceans, where nonlocal 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 outgoing longwave radiation in the model than observed. Different model global mean trends are evident, however, possibly hinting at too much positive cloud feedback in the model.

  16. Radiative heating and cooling rates in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Gille, John C.; Lyjak, Lawrence V.

    1986-01-01

    One of the limitations to the accurate calculation of radiative heating and cooling rates in the stratosphere and mesosphere has been the lack of accurate data on the atmospheric temperature and composition. Data from the LIMS experiment on Nimbus-7 has been extended to the South Pole with the aid of other observations. The data have been used as input to codes developed by Ramanathan and Dickinson to calculate the individual components and the net radiative heating rates from 100-0.1 mb. Solar heating due to ozone, nitrogen dioxide, carbon dioxide, water vapor and oxygen is shown to be nearly balanced by cooling in the thermal infrared spectral region due to carbon dioxide, ozone and water vapor. In the lower stratosphere, infrared transfer by ozone leads to heating that is sensitive to the distribution of tropospheric ozone, clouds and water vapor. The heating and cooling rates are adjusted slightly in order to satisfy the global mass balance. The results are in qualitative agreement with earlier calculations, but show additional detail. There is as strong temporal and vertical variation of cooling in the tropics. Radiative relaxation times are as short as 7 days or less at the stratopause.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

    The four entry probes of the Pioneer Venus mission measured the radiative net flux in the atmosphere of Venus at latitudes of 60 deg. N, 31 deg. S, 27 deg. S, and 4 deg. N. The three higher latitude probes carried instruments (small probe net flux radiometers; SNFR) with external sensors. The measured SNFR net fluxes are too large below the clouds, but an error source and correction scheme have been found (H. E. Revercomb, L. A. Sromovsky, and V. E. Suomi, 1982, Icarus 52, 279-300). The near-equatorial probe carried an infrared radiometer (LIR) which viewed the atmosphere through a window in the probe. The LIR measurements are reasonable in the clouds, but increase to physically unreasonable levels shortly below the clouds. The probable error source and a correction procedure are identified. Three main conclusions can be drawn from comparisons of the four corrected flux profiles with radiative transfer calculations: (1) thermal net fluxes for the sounder probe do not require a reduction in the Mode 3 number density as has been suggested by O.B. Toon, B. Ragent, D. Colburn, J. Blamont, and C. Cot (1964. Icarus 37, 143-160), but the probe measurements as a whole are most consistent with a significantly reduced mode 3 contribution to the cloud opacity; (2) at all probe sites, the fluxes imply that the upper cloud contains a yet undetected source of IR opacity; and (3) beneath the clouds the fluxes at a given altitude increase with latitude, suggesting greater IR cooling below the clouds a( high latitudes and water vapor mixing ratios of about 2-5 x 10(exp -5) near 6 deg., 2-5 x 10(exp -11) near 30 deg., and less than 5 x 10(exp -4 ) near the equator. The suggested latitudinal variation of IR cooling is consistent with descending motions at high latitudes, and it is speculated that it could provide an important additional drive for the general circulation.

  6. 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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

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

  9. Large radiative forcing efficiency of atmospheric aerosols over the Himalaya

    NASA Astrophysics Data System (ADS)

    Gasbarra, Daniele; di Sarra, Alcide; Meloni, Daniela; Bonasoni, Paolo; Di Biagio, Claudia; Gobbi, Gian Paolo; Marinoni, Angela; Pietro Verza, Gian; Vuillermoz, Elisa

    2014-05-01

    This study is based on measurements made at the Nepal Climate Observatory at Pyramid (NCO-P, 27.95 N, 86.82 E), located at 5079 m altitude in the Sagamartha National Park, Eastern Nepal Himalaya. We analised seasonal variations of solar downward irradiance (SW), columnar water vapour content (wv), aerosol optical depth at 500 nm (τ) and surface albedo (A) in the period between 2007 and 2010, in order to obtain the radiative perturbations produced by aerosols in the SW. SW measurements are carried out by a CMP21 pyranometer, while A is derived from a CNR1 radiometer. Values of wv and τ are retrieved from the measurements by the EVK2-CNR Cimel sunphotometer operating within the AERONET network. τ was found to be lower than 0.1 in 98% of the cases. However, during the pre-monsoon season, especially in the months of April and May, cases with τ reaching 0.27 were recorded. The aerosol surface shortwave radiative effect in cloud-free periods was estimated during the elevated aerosol optical depth cases using different methods. The 'hybrid method' was applied using experimental measurements of solar downward irradiance and simulations made with the MODTRAN (MODerate resolution atmospheric TRANsmission) model. The dependency of SW on A and wv was determined from MODTRAN simulations, and was used to correct experimental measurements for albedo and water vapour changes. The radiative perturbation produced by aerosol was thus obtained as the difference between the measured irradiances and the modelled values for aerosol-free conditions and the same water vapour and albedo values, and at the same solar zenith angle. The aerosol radiative effect was also derived by comparing elevated and low aerosol optical depth cases, at similar values of solar zenith angle, albedo, and column water vapour. In addition the direct method, relating SW to changes in τ, was also used. These three methods produce consistent results. Although the overall aerosol radiative perturbation is small

  10. Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Jacobson, Mark Z.

    2001-02-01

    Aerosols affect the Earth's temperature and climate by altering the radiative properties of the atmosphere. A large positive component of this radiative forcing from aerosols is due to black carbon-soot-that is released from the burning of fossil fuel and biomass, and, to a lesser extent, natural fires, but the exact forcing is affected by how black carbon is mixed with other aerosol constituents. From studies of aerosol radiative forcing, it is known that black carbon can exist in one of several possible mixing states; distinct from other aerosol particles (externally mixed) or incorporated within them (internally mixed), or a black-carbon core could be surrounded by a well mixed shell. But so far it has been assumed that aerosols exist predominantly as an external mixture. Here I simulate the evolution of the chemical composition of aerosols, finding that the mixing state and direct forcing of the black-carbon component approach those of an internal mixture, largely due to coagulation and growth of aerosol particles. This finding implies a higher positive forcing from black carbon than previously thought, suggesting that the warming effect from black carbon may nearly balance the net cooling effect of other anthropogenic aerosol constituents. The magnitude of the direct radiative forcing from black carbon itself exceeds that due to CH4, suggesting that black carbon may be the second most important component of global warming after CO2 in terms of direct forcing.

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

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  12. 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.

  13. 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.

  14. The affection analysis and compensation for atmospheric overfall in free space optical communication system

    NASA Astrophysics Data System (ADS)

    Yuan, Xiuhua; Wang, Jin; Huang, Dexiu; Liu, Deming

    2004-12-01

    The Free Space optical communication (FSO) or wireless optical communication, utilizes the atmospheric medium as transmission channel, where random variety such as fog, atomy and atmosphere flash and the atmospheric turbulence will badly affect the propagation of light, the receiving signal is easily swung and drifted with the change of weather. In this paper, we discussed the attenuation of the atmospheric channel and analyzed the signal characteristics in the condition of the atmospheric overfall, for the OOK modulation, discussed the receiving signal distribution in the atmospheric channel taking account for the noise gain of the light detector, and based on the principle of the Hartman-Shack sensor, we designed a wave-front distortion compensation system with fiber coupler. The signal fading resulted from wave-front phase distortion was compensated effectively by using the compensation system.

  15. 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.

  16. 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.

  17. Surface shortwave aerosol radiative forcing during the Atmospheric Radiation Measurement Mobile Facility deployment in Niamey, Niger

    SciTech Connect

    McFarlane, Sally A.; Kassianov, Evgueni I.; Barnard, James C.; Flynn, Connor J.; Ackerman, Thomas P.

    2009-03-18

    This study presents ground-based remote sensing measurements of aerosol optical properties and corresponding shortwave surface radiative effect calculations for the deployment of the Atmospheric Radiation Measurement (ARM) Program’s Mobile Facility (AMF) to Niamey, Niger during 2006. Aerosol optical properties including aerosol optical depth (AOD), single scattering albedo (SSA), and asymmetry parameter (AP) were derived from multi-filter rotating shadowband radiometer (MFRSR) measurements during the two dry seasons (Jan-Apr and Oct-Dec) at Niamey. The vertical distribution of aerosol extinction was derived from the collocated micropulse lidar (MPL). The aerosol optical properties and vertical distribution of extinction varied significantly throughout the year, with higher AOD, lower SSA, and deeper aerosol layers during the Jan-Apr time period, when biomass burning aerosol layers were more frequent. Using the retrieved aerosol properties and vertical extinction profiles, broadband shortwave surface fluxes and atmospheric heating rate profiles were calculated. Corresponding calculations with no aerosol were used to estimate the aerosol direct radiative effect at the surface. Comparison of the calculated surface fluxes to observed fluxes for non-cloudy periods indicated that the remote sensing retrievals provided a reasonable estimation of the optical properties, with mean differences between calculated and observed fluxes of less than 5 W/m2 and RMS differences less than 25 W/m2. Sensitivity tests for a particular case study showed that the observed fluxes could be matched with variations of < 10% in the inputs to the radiative transfer model. We estimated the daily-averaged aerosol radiative effect at the surface by subtracting the clear calculations from the aerosol calculations. The average daily SW aerosol radiative effect over the study period was -27 W/m2, which is comparable to values estimated from satellite data and from climate models with sophisticated

  18. A combined radiative transfer model for sea ice, open ocean, and atmosphere

    NASA Astrophysics Data System (ADS)

    Fuhrhop, Rolf; Grenfell, Thomas C.; Heygster, Georg; Johnsen, Klaus-Peter; Schlüssel, Peter; Schrader, Meeno; Simmer, Clemens

    1998-03-01

    A radiative transfer model to compute brightness temperatures in the microwave frequency range for polar regions including sea ice, open ocean, and atmosphere has been developed and applied to sensitivity studies and retrieval algorithm development. The radiative transfer within sea ice is incorporated according to the "many layer strong fluctuation theory" of Stogryn [1986, 1987] and T. Grenfell [Winebrenner et al., 1992]. The reflectivity of the open water is computed with the three-scale model of Schrader [1995]. Both surface models supply the bistatic scattering coefficients, which define the lower boundary for the atmospheric model. The atmospheric model computes the gaseous absorption by the Liebe et al. [1993] model. Scattering by hydrometeors is determined by Mie or Rayleigh theory. Simulated brightness temperatures have been compared with special sensor microwave imager (SSM/I) observations. The comparison exhibits shortcomings of the ice model for 37 GHz. Applying a simple ad hoc correction at this frequency gives consistent comparison results within the range of observational accuracy. The simulated brightness temperatures show the strong influence of clouds and variations of wind speed over the open ocean, which will affect the sea ice retrieval even for an ice-covered ocean. Simulated brightness temperatures have been used to train a neural network algorithm for the total sea ice concentration, which accounts for these effects. Sea ice concentrations sensed from the SSM/I data using the network and the NASA sea ice algorithm show systematic differences in dependence on cloudiness.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Addition Laws for Intensities of Radiation Emerging from Scattering Atmospheres Containing Energy Sources

    NASA Astrophysics Data System (ADS)

    Nikoghossian, A. G.; Kapanadze, N. G.

    2016-03-01

    A group theoretical approach is developed for solving astrophysical radiative transfer problems described in a previous series of papers. Addition laws for observed radiative intensities are derived for the case in which atmospheres not only absorb and scatter radiation incident on them, but radiate themselves because of energy sources contained within them. As an illustration of the application of these laws, several special radiative transfer problems which we believe are of practical interest are discussed.

  4. 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.

  5. 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.

  6. 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.

  7. Processing of Atmospheric Organic Matter by California Radiation Fogs

    NASA Astrophysics Data System (ADS)

    Collett, J. L.; Youngster, S. B.; Lee, T.; Chang, H.; Herckes, P.

    2005-12-01

    . Consequently, removal of organic compounds by fog drop deposition is slowed by the lower settling velocities of smaller droplets. Despite this, sedimentation of droplets from long-lived radiation fogs provides an effective mechanism for cleansing the atmosphere of carbonaceous aerosol particles, with deposition velocities of TOC in fogs observed on the order of a few cm/s.

  8. Atmospheric Teleconnection over Eurasia Induced by Aerosol Radiative Forcing during Boreal Spring

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

    The direct effects of aerosols on global and regional climate during boreal spring are investigated based on numerical simulations with the NASA Global Modeling and Assimilation Office finite-volume general circulation model (fvGCM) with Microphyics of Clouds with the Relaxed Arakawa Schubert Scheme (McRAS), using aerosol forcing functions derived from the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The authors find that anomalous atmospheric heat sources induced by absorbing aerosols (dust and black carbon) excite 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, that is, South Asia, East Asia, and northern and western Africa. Significant atmospheric heating is found in regions with large loading of dust (over northern Africa and the Middle East) and black carbon (over Southeast 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 concentrations are low. Analyses of circulation anomalies show that the dipole anomaly is a part of an atmospheric teleconnection pattern 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 associated with the regional circulations. The surface temperature signature associated with the aerosol-induced teleconnection bears striking resemblance to the spatial pattern of observed long-term trend in surface temperature over Eurasia. Additionally, the boreal spring wave train pattern is similar to that reported by Fukutomi et al. associated with the boreal summer

  9. Processing of atmospheric organic matter by California radiation fogs

    NASA Astrophysics Data System (ADS)

    Collett, Jeffrey L., Jr.; Herckes, Pierre; Youngster, Sarah; Lee, Taehyoung

    2008-03-01

    Considerable effort has been put into characterizing the ionic composition of fogs and clouds over the past twenty-five years. Recently it has become evident that clouds and fogs often contain large concentrations of organic material as well. Here we report findings from a series of studies examining the organic composition of radiation fogs in central California. Organic compounds in these fogs comprise a major fraction of total solute mass, with total organic carbon sometimes reaching levels of several tens of mg/L. This organic matter is comprised of a wide variety of compounds, ranging from low molecular weight organic acids to high molecular weight compounds with molecular masses approaching several hundred to a thousand g/mole. The most abundant individual compounds are typically formic acid, acetic acid, and formaldehyde. High concentrations are also observed of some dicarboxylic acids (e.g., oxalate) and dicarbonyls (e.g., glyoxal and methylglyoxal) and of levoglucosan, an anhydrosugar characteristically emitted by biomass combustion. Many other compounds have been identified in fog water by GC/MS, including long chain n-alkanoic acids, n-alkanes, PAH, and others, although these compounds typically comprise a total of only a few percent of fog TOC. Measurements of fog scavenging of organic and elemental carbon reveal preferential scavenging of organic carbon. Tracking of individual organic compounds utilized as source type markers suggests the fogs differentially scavenge carbonaceous particles from different source types, with more active processing of wood smoke than vehicle exhaust. Observations of high deposition velocities of fog-borne organic carbon, in excess of 1 cm/s, indicate that fogs in the region represent an important mechanism for cleansing the atmosphere of pollution.

  10. Effects of Clouds on Cross-Atmospheric Radiative Flux Divergence: Case Studies in Different Cloud Conditions

    NASA Astrophysics Data System (ADS)

    Ghate, V. P.; Miller, M. A.

    2013-12-01

    Clouds have a profound effect on the amount of radiation absorbed across the atmospheric column. The amount of absorption mainly depends on the location and type of the clouds, the albedo of the surface and profile of water vapor mixing ratio in the atmospheric column. In this study we have used the data collected during the deployment of Atmospheric Radiation Measurement (ARM)'s first Mobile Facility (AMF#1) at the island of Graciosa in the North Atlantic and at the Niamey, Niger to assess the impact of different cloud types on the cross-atmospheric radiative flux divergence. The cloud structure was retrieved using the data collected by a vertically pointing w-band cloud radar, a micro-pulse lidar, laser ceilometer among other instruments. The profiles of temperature, moisture and winds were measured by balloon borne radiosondes. The radiation at the surface were measured by broadband radiometers, while the radiation at the top of the atmosphere were measured by the Geostationary Earth Radiation Budget (GERB) radiometers onboard the Meteosat Second Generation (MSG) satellite. Simulations of a 1-dimensional radiative transfer model called as Rapid Radiative Transfer Model (RRTM) having representation of cloud and aerosol properties are made to assess the relative impact of different cloud types and water vapor on spectral bands both in the shortwave and longwave radiation spectrum. Results from four case-studies which had cloud free conditions, single layered stratocumulus clouds, broken shallow cumulus clouds and high level cirrus clouds respectively will be presented.

  11. Appropriate line profiles for radiation modeling in the detection of atmospheric pollutants

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.

    1973-01-01

    Absorption by Lorentz, Doppler, and Voight lines are compared for a range of atmospheric parameters. It is found that, for the intermediate path lengths, the use of the combined Lorentz-Doppler (Voight) profile is essential in calculating the atmospheric transmittance. A brief review of band models, to approximate the absorption over certain frequency interval, is presented. Expressions for total radiative energy emergent from the atmosphere are given which, with appropriate line or band models, can be used to reduce the data obtained from radiation measurement by an instrument mounted on an aircraft or a satellite. By employing the inversion procedure, the concentration of atmospheric pollutants can be obtained from the measured data.

  12. 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.

  13. Temporal fluctuations of laser beam radiation in atmospheric precipitation

    NASA Astrophysics Data System (ADS)

    Kabanov, M. V.; Zhukov, A. F.; Tsvyk, R. Sh.

    1988-02-01

    The present results of experimental investigations of laser beam intensity temporal fluctuations in atmospheric precipitation indicate the difficulty of obtaining a priori intensity fluctuation estimates in a real atmosphere. The few cases in which one can analytically describe the spectrum and intensity fluctuation variance are nevertheless important for practical purposes. By measuring the intensity fluctuation spectra and intensity variance, it is possible to crudely estimate the precipitation and atmospheric turbulence parameters.

  14. 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.

  15. Do metallic ports in tissue expanders affect postmastectomy radiation delivery?

    SciTech Connect

    Damast, Shari; Beal, Kathryn . E-mail: bealk@mskcc.org; Ballangrud, Ase; Losasso, Thomas J.; Cordeiro, Peter G.; Disa, Joseph J.; Hong, Linda; McCormick, Beryl L.

    2006-09-01

    Purpose: Postmastectomy radiation therapy (PMRT) is often delivered to patients with permanent breast implants. On occasion, patients are irradiated with a tissue expander (TE) in place before their permanent implant exchange. Because of concern of potential under-dosing in these patients, we examined the dosimetric effects of the Magna-Site (Santa Barbara, CA) metallic port that is present in certain TEs. Methods and Materials: We performed ex vivo film dosimetry with single 6-MV and 15-MV photon beams on a water phantom containing a Magna-Site disc in two orientations. Additionally, using in vivo films, we measured the exit dose from 1 patient's TE-reconstructed breast during chest wall treatment with 15-MV tangent beams. Finally, we placed thermoluminescent dosimeters (TLDs) on 6 patients with TEs who received PMRT delivered with 15-MV tangent beams. Results: Phantom film dosimetry revealed decreased transmission in the region of the Magna-Site, particularly with the magnet in the parallel orientation (at 22 mm: 78% transmission with 6 MV, 84% transmission with 15 MV). The transmission measured by in vivo films during single beam treatment concurred with ex vivo results. TLD data showed acceptable variation in median dose to the skin (86-101% prescription dose). Conclusion: Because of potential dosimetric effects of the Magna-Site, it is preferable to treat PMRT patients with permanent implants. However, it is not unreasonable to treat with a TE because the volume of tissue affected by attenuation from the Magna-Site is small. In this scenario, we recommend using 15 MV photons with compensating bolus.

  16. A new model for atmospheric radiation under clear sky condition at various altitudes

    NASA Astrophysics Data System (ADS)

    Dai, Qiumin; Fang, Xiande

    2014-09-01

    Atmospheric radiation is one of the major factors that dominate the thermal behaviors of aerostats. A high-performance model is needed to evaluate the atmospheric radiation. Based on the atmospheric radiation database containing 24,862 data points compiled from 7 stations with the elevation from sea level to 2373 m and the reference code MODTRAN, a new atmospheric radiation model is proposed using regression and optimization software. It has excellent prediction accuracy with the coefficient of determination of 0.94, the root mean square error of 15.1 W/m2, and the mean absolute percentage error of 4.13% for the database. Comparison with the well-known existing model shows that the new model has the highest prediction accuracy. The new model predictions agree with the MODTRAN calculations at various altitudes very well, and thus it can be used for estimating the thermal performances of a high altitude aerostat.

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

    NASA Astrophysics Data System (ADS)

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

    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 personel 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.

  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. SHDOM: Spherical Harmonic Discrete Ordinate Method for atmospheric radiative transfer

    NASA Astrophysics Data System (ADS)

    Evans, K. Franklin

    2015-08-01

    The Spherical Harmonic Discrete Ordinate Method (SHDOM) radiative transfer model computes polarized monochromatic or spectral band radiative transfer in a one, two, or three-dimensional medium for either collimated solar and/or thermal emission sources of radiation. The model is written in a variant of Fortran 77 and in Fortran90 and requires a Fortran 90 compiler. Also included are programs for generating the optical property files input to SHDOM from physical properties of water cloud particles and aerosols.

  20. 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

  1. The Havemann-Taylor Fast Radiative Transfer Code: Exact fast radiative transfer for scattering atmospheres using Principal Components (PCs)

    NASA Astrophysics Data System (ADS)

    Havemann, Stephan; Thelen, Jean-Claude; Taylor, Jonathan P.; Keil, Andreas

    2009-03-01

    The Havemann-Taylor Fast Radiative Transfer Code (HT-FRTC) has been developed for the simulation of highly spectrally resolved measurements from satellite based (i.e. Infrared Atmospheric Sounding Interferometer (IASI), Atmospheric Infrared Sounder (AIRS)) and airborne (i.e. Atmospheric Research Interferometer Evaluation System (ARIES)) instruments. The use of principle components enables the calculation of a complete spectrum in less than a second. The principal compoents are derived from a diverse training set of atmospheres and surfaces and contain their spectral characteristics in a highly compressed form. For any given atmosphere/surface, the HT-FRTC calculates the weightings (also called scores) of a few hundred principal components based on selected monochromatic radiative transfer calculations, which is far cheaper than thousands of channel radiance calculations. By intercomparison with line-by-line and other fast models the HT-FRTC has been shown to be accurate. The HT-FRTC has been successfully applied to simultaneous variational retrievals of atmospheric temperature and humidity profiles, surface temperature and surface emissivity over land. This is the subject of another presentation at this conference. The HT-FRTC has now also been extended to include an exact treatment of scattering by aerosols/clouds. The radiative transfer problem is solved using a discrete ordinate method (DISORT). Modelling results at high-spectral resolution for non-clear sky atmospheres obtained with the HT-FRTC are presented.

  2. Modeling of Large Methane Releases and their affect on the Chemistry of the Atmosphere

    NASA Astrophysics Data System (ADS)

    Bergmann, D. J.; Cameron-Smith, P. J.; Elliot, S.; Reagan, M. T.; Maltrud, M. E.

    2009-12-01

    A vast quantity of methane is locked in solid phase as methane clathrates in ocean sediments (as much carbon as all other fossil fuels combined). Rapid destabilization of the clathrates due to climate warming would significantly increase methane emissions from the ocean. This would result in a number of affects including strong greenhouse heating, increased surface ozone, reduced stratospheric ozone, and intensification of the ozone hole. Many of the affects in the chemistry of the atmosphere are non-linear and difficult to estimate without a detailed model. As part of the DOE IMPACTS project on abrupt climate change we have used our 3D global atmospheric chemistry model (IMPACT) to take a first look at some of these affects. This model includes detailed chemistry of the troposphere (including isoprene and other hydrocarbons) and the stratosphere (including the important chlorine and bromine compounds). We ran the model at 4x5 degree resolution with methane simply scaled to present day emissions. We show results for 1x, 2x, 10x, 100x, and 1000x emission scenarios. We analyzed the results after the simulations have reached steady state (many years of simulation) and show the affect of these large releases on tropospheric air quality, the “health” of the stratosphere, and greenhouse heating. Substantial increases were seen in atmospheric methane lifetime, a positive feedback, due to the increased methane reducing the OH concentration. In the future we will couple our atmospheric chemistry to a complete Earth system model (based on CCSM) for methane including ocean ecosystem, ocean sediment and boreal land models to give more accurate estimates of the emission term and to look at the full system response.

  3. 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

  4. Stochastic Model for Shortwave Radiation Transfer in a Multiple-Layered Atmosphere: Surface Global Radiation in Cloudless Conditions

    NASA Astrophysics Data System (ADS)

    Ceballos, Juan Carlos; de Souza, Juarez Dantas; da Silva, Bernardo Barbosa

    2009-03-01

    A two-flux method is presented, which describes propagation of solar radiation in the atmosphere as a random walk of diffuse photons among several atmospheric layers. Results are obtained in terms of absorption probabilities in each layer, at ground and within sky, allowing to easily introduce and to analyze influence of profiles of the main atmospheric absorbers (ozone, aerosols and water vapor). Global radiation is obtained by integration of monochromatic irradiances. Application of this model to cloudless situations in the extreme cases of rural environment and high aerosol load by burning biomass shows good results when compared with SBDART code (they have a systematic deviation of +10 Wṡm-2), and both differ from ground measurements of global radiation within 30 to 50 Wṡm-2. This difference could be lowered having a better definition of aerosol load during daytime. It is observed that the stochastic model performance is five times faster than SBDART.

  5. Ionizing Radiation Impairs T Cell Activation by Affecting Metabolic Reprogramming

    PubMed Central

    Li, Heng-Hong; Wang, Yi-wen; Chen, Renxiang; Zhou, Bin; Ashwell, Jonathan D.; Fornace, Albert J.

    2015-01-01

    Ionizing radiation has a variety of acute and long-lasting adverse effects on the immune system. Whereas measureable effects of radiation on immune cell cytotoxicity and population change have been well studied in human and animal models, little is known about the functional alterations of the surviving immune cells after ionizing radiation. The objective of this study was to delineate the effects of radiation on T cell function by studying the alterations of T cell receptor activation and metabolic changes in activated T cells isolated from previously irradiated animals. Using a global metabolomics profiling approach, for the first time we demonstrate that ionizing radiation impairs metabolic reprogramming of T cell activation, which leads to substantial decreases in the efficiency of key metabolic processes required for activation, such as glucose uptake, glycolysis, and energy metabolism. In-depth understanding of how radiation impacts T cell function highlighting modulation of metabolism during activation is not only a novel approach to investigate the pivotal processes in the shift of T cell homeostasis after radiation, it also may lead to new targets for therapeutic manipulation in the combination of radiotherapy and immune therapy. Given that appreciable effects were observed with as low as 10 cGy, our results also have implications for low dose environmental exposures. PMID:26078715

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  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-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.

  18. 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.

  19. 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.

  20. 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.

  1. Monochromatic calculations of atmospheric radiative transfer due to molecular line absorption

    NASA Technical Reports Server (NTRS)

    Chou, M.-D.; Kouvaris, L.

    1986-01-01

    Sensitivity studies related to the effects of line cutoff, spectral resolution, and temperature and pressure interpolations in radiative transfer have been performed so that a data set of absorption coefficients for water vapor, CO2, and O3 may be created efficiently. Results show that computations of absorption coefficients are affected only slightly by cutting a line off at a wave number 190 times the Lorentz half width from the center, or equivalently, cutting off 0.33 percent of the line intensity from the wings. To achieve a relative cooling rate error smaller than 2 percent, it is sufficient to precompute the absorption coefficient at three temperatures (210, 250, and 290 K) and 19 pressures with Delta (log 10 p) = 0.2. The absorption coefficient at other conditions can be interpolated linearly with pressure and exponentially with a quadratic in temperature. For the spectral resolution the absorption coefficients can be adequately computed at 0.01, 0.002, 0.005, and 0.025/cm intervals in the thermal water vapor, the CO2 and O3 bands, and the solar water vapor bands, respectively, which limits the error to only a few percent in the cooling and heating rates. Using the precomputed absorption coefficients, repeated monochromatic calculations of atmospheric heating/cooling rates for radiation model developments and for comparison with less detailed calculations are no longer difficult.

  2. 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.

  3. 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.

  4. MSG-7: Atmospheric Penetration of Solar Radiation in the Range of Schumann-runge Bands

    NASA Technical Reports Server (NTRS)

    Frederick, J. E.

    1982-01-01

    There have been major efforts in measuring extraterrestrial solar irradiance for use in atmospheric studies. The quantity of immediate relevance to theoretical studies is the number of photons which reach a given altitude in the middle atmosphere. Current models compute the attenuated radiation field but the cross sections available for the major absorbers, O2 and O3, often come from experiments that are now quite old. Balloon measurements show some significant differences between the predicted and observed ultraviolet radiation field between 30 and 40 km. The wavelength region to be studied includes Lyman alpha plus the range 175 nm to the visible. Specific topics to be addressed are as follows: (1) the cross sections of the major absorbers, O2 and O3 including the Schumann-Runge bands as a subset; (2) comparison of the in situ measurements of the attenuated radiation field with calculations; and (3) the relevance of the scattered and reflected radiation fields for middle atmospheric processes.

  5. 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.

  6. 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.

  7. 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

  8. Modeled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    NASA Astrophysics Data System (ADS)

    Samset, B. H.; Myhre, G.; Herber, A.; Kondo, Y.; Li, S.-M.; Moteki, N.; Koike, M.; Oshima, N.; Schwarz, J. P.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Berntsen, T. K.; Bian, H.; Chin, M.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2014-08-01

    Atmospheric black carbon (BC) absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF). However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparision. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modeled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  9. Modelled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    NASA Astrophysics Data System (ADS)

    Samset, B. H.; Myhre, G.; Herber, A.; Kondo, Y.; Li, S.-M.; Moteki, N.; Koike, M.; Oshima, N.; Schwarz, J. P.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Berntsen, T. K.; Bian, H.; Chin, M.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2014-11-01

    Atmospheric black carbon (BC) absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF). However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long-range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present-day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparison. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modelled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  10. The absorption of solar radiation by the Arctic atmosphere during the haze season and its effects on the radiation balance

    NASA Technical Reports Server (NTRS)

    Valero, F. P. J.; Ackerman, T. P.; Gore, W. J. Y.

    1984-01-01

    Measurements of broadband spectral absorption of solar radiation by the Arctic atmosphere during haze events are reported. A preliminary analysis of the data indicates that large changes occur in the radiative transfer processes in the Arctic during haze events. For example, the planetary albedo is estimated to increase by 2.5 percent over the ocean and to decrease by 9 percent over the ice cap. Changes of such magnitude in the radiative parameters have the potential for significant climatic effects. The need for further experimental and modeling efforts is emphasized.

  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. 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.

  13. SOURCES AND RADIATIVE PROPERTIES OF ORGANOSULFATES IN THE ATMOSPHERE

    EPA Science Inventory

    It is expected that these studies will provide mechanistic insight to how SOA forms under acidic conditions and how it impacts direct and indirect radiative forcing. Understanding the chemical and physical properties of SOA will lead to future advancements in the predictive...

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  15. Non-equilibrium effects in atmospheric characteristic oscillations due to radiation balance

    NASA Astrophysics Data System (ADS)

    Nurgaliyeva, K. E.; Somsikov, V. M.

    2008-12-01

    Nowadays researches on global change of climate are faces the challenge of insufficient development of open system theory. In this connection the problem of energy and entropy exchange process between solar radiation and atmospheric gas influence on atmospheric dynamics in the frames of non-equilibrium thermodynamics was studied in this work. For this purpose the equations of flow [fluid] dynamics for interacting medium - gas and radiation - with taking into account the entropy production in atmosphere and its exchanging between gas and radiation were used in this work. Dispersion relation numerical analysis of atmospheric gravity waves (AGWs) in non-equilibrium atmosphere was carried out. It has been established that the spectra in the daytime hours shifts on high-frequency region in comparison with nighttime spectra. This difference can reach several percent in certain atmospheric regions. For the spectrum of the equilibrium model of the atmosphere the difference between the daytime and nighttime spectra makes up several fractions of percent. A comparison of the theoretical calculations of AGWs spectrum with observations confirmed the availability of non-equilibrium effects in the AGWs spectral composition. In particular, that concerns of Antarctic data results gave the difference is about 4 percent, Almaty data results ranges between 1.3 - 6 per cent in depends of season. Investigation of wave disturbances on sunset and sunrise periods of time shows that there is a tendency for low frequency region at evening-time spectra and high frequency region at morning- time spectra.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Analytical properties of the radiance in atmospheric radiative transfer theory

    NASA Astrophysics Data System (ADS)

    Otto, Sebastian

    2014-01-01

    It is demonstrated mathematically strictly that state density functions, as the radiance (specific intensity), exist to describe certain state properties of transported photons on microscopic and the state of the radiation field on macroscopic scale, which have independent physical meanings. Analytical properties as boundedness, continuity, differentiability and integrability of these functions to describe the photon transport are discussed. It is shown that the density functions may be derived based on the assumption of photons as real particles of non-zero and finite size, independently of usual electrodynamics, and certain historically postulated functional relationships between them were proved, that is, these functions can be derived mathematically strictly and consistently within the framework of the theory of the phenomenological radiative transfer if one takes the theory seriously by really assuming photons as particles. In this sense these functions may be treated as fundamental physical quantities within the scope of this theory, if one considers the possibility of the existence of photons.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. Upper atmospheric probing by resonance fluorescence excited by tunable laser radiation.

    NASA Technical Reports Server (NTRS)

    Saunders, A. R.; Mumola, P. B.

    1972-01-01

    Consideration of the application of the measurement of resonance fluorescence radiation excited by tunable laser radiation to the detection of atomic, molecular, and ionic species in the upper atmosphere. The species considered are N2, N2(+), NO, NO(+), O2(+), CO, CO(+), CH, Na, K, and Ca. Calculations of the resonance scattering cross sections, photon returns, and signal-to-noise ratios are given for these species for a range of conditions. Based on a probing altitude of 100 km, the detections of N2, NO, CO, CH, O2, and the trace metals appear feasible with state-of-the-art systems and within the concentration range present in the atmosphere.

  9. 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.

  10. 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

  11. Validation of AERONET estimates of atmospheric solar fluxes and aerosol radiative forcing by ground-based broadband measurements

    NASA Astrophysics Data System (ADS)

    GarcíA, O. E.; DíAz, A. M.; Expósito, F. J.; DíAz, J. P.; Dubovik, O.; Dubuisson, P.; Roger, J.-C.; Eck, T. F.; Sinyuk, A.; Derimian, Y.; Dutton, E. G.; Schafer, J. S.; Holben, B. N.; GarcíA, C. A.

    2008-11-01

    The AErosol RObotic NETwork (AERONET) estimates of instantaneous solar broadband fluxes (F) at surface have been validated through comparison with ground-based measurements of broadband fluxes at Mauna Loa Observatory (MLO) and by the Baseline Surface Radiation (BSRN) and the Solar Radiation Networks (SolRad-Net) during the period 1999-2005 and 1999-2006, respectively. The uncertainties in the calculated aerosol radiative forcing (ΔF) and radiative forcing efficiency (ΔFeff) at the bottom of the atmosphere were also assessed. The stations have been selected attempting to cover different aerosols influences and hence radiative properties: urban-industrial, biomass burning, mineral dust, background continental, maritime aerosols and free troposphere. The AERONET solar downward fluxes at surface agree with ground-based measurements in all situations, with a correlation higher than 99% whereas the relation of observed to modeled fluxes ranges from 0.98 to 1.02. Globally an overestimation of 9 ± 12 Wm-2 of solar measurements was found, whereas for MLO (clear atmosphere) the differences decrease noticeably up to 2 ± 10 Wm-2. The highest dispersion between AERONET estimates and measurements was observed in locations dominated by mineral dust and mixed aerosols types. In these locations, the F and ΔF uncertainties have shown a modest increase of the differences for high aerosol load, contrary to ΔFeff which are strongly affected by low aerosol load. Overall the discrepancies clustered within 9 ± 12 Wm-2 for ΔF and 28 ± 30 Wm-2 per unit of aerosol optical depth, τ, at 0.55 μm for ΔFeff, where the latter is given for τ(0.44 μm) ≥ 0.4. The error distributions have not shown any significant tendency with other aerosol radiative properties as well as size and shape particles.

  12. 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.

  13. Radiation doses from Hanford Site releases to the atmosphere and the Columbia River

    SciTech Connect

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

    1996-10-01

    Radiation doses to individuals were estimated for the years 1944-1992 as part of the Hanford Dose Reconstruction Project (HEDR). The dose estimates were based on the radioactive releases to the atmosphere and Columbia River from the Hanford Site in southcentral Washington State. Conceptual models, computer codes, and previously published dose estimates were used to reconstruct doses. The most significant exposure pathway was found to be the consumption of cow`s milk containing {sup 131}I. The median cumulative dose estimates to the thyroid of children ranged from <0.7 mGy to 2.3 Gy throughout the study area, depending upon residence location. The highest estimated cumulative dose to a child ranged from 0.6-8.4 Gy (5th and 95th percentiles) with a median of 2.3 Gy based on 100 Monte Carlo realizations. The geographic distribution of the dose levels was directly related to the pattern of {sup 131}I deposition and was affected by the distribution of commercial milk and leafy vegetables. For the atmospheric pathway, the highest cumulative effective dose equivalent to an adult was estimated to be 12 mSv at Ringold, Washington, for the period 1944-1992. For the Columbia River pathway, cumulative effective dose equivalent estimates ranged from <5 mSv to 15 mSv 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 {sup 32}P and {sup 65}Zn.

  14. 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.

  15. Do diurnal aerosol changes affect daily average radiative forcing?

    NASA Astrophysics Data System (ADS)

    Kassianov, Evgueni; Barnard, James; Pekour, Mikhail; Berg, Larry K.; Michalsky, Joseph; Lantz, Kathy; Hodges, Gary

    2013-06-01

    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 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.

  16. An Iterative Phase-Space Explicit Discontinuous Galerkin Method for Stellar Radiative Transfer in Extended Atmospheres

    SciTech Connect

    de Almeida, V.F.

    2004-01-28

    A phase-space discontinuous Galerkin (PSDG) method is presented for the solution of stellar radiative transfer problems. It allows for greater adaptivity than competing methods without sacrificing generality. The method is extensively tested on a spherically symmetric, static, inverse-power-law scattering atmosphere. Results for different sizes of atmospheres and intensities of scattering agreed with asymptotic values. The exponentially decaying behavior of the radiative field in the diffusive-transparent transition region and the forward peaking behavior at the surface of extended atmospheres were accurately captured. The integrodifferential equation of radiation transfer is solved iteratively by alternating between the radiative pressure equation and the original equation with the integral term treated as an energy density source term. In each iteration, the equations are solved via an explicit, flux-conserving, discontinuous Galerkin method. Finite elements are ordered in wave fronts perpendicularly to the characteristic curves so that elemental linear algebraic systems are solved quickly by sweeping the phase space element by element. Two implementations of a diffusive boundary condition at the origin are demonstrated wherein the finite discontinuity in the radiative intensity is accurately captured by the proposed method. This allows for a consistent mechanism to preserve photon luminosity. The method was proved to be robust and fast, and a case is made for the adequacy of parallel processing. In addition to classical two-dimensional plots, results of normalized radiative intensity were mapped onto a log-polar surface exhibiting all distinguishing features of the problem studied.

  17. 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.

  18. 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.

  19. Interactive effects of atmospheric carbon dioxide and ultraviolet-B radiation on cotton growth and physiology

    NASA Astrophysics Data System (ADS)

    Reddy, K. Raja; Koti, S.; Zhao, Duli; Kakani, Vijaya Gopal; Gao, Wei

    2003-11-01

    Increasing surface UV-B radiation (UV-B) and atmospheric carbon dioxide concentration [(CO2)] are two major issues of climate change and agriculture. Although numerous studies have evaluated elevated UV-B or (CO2) effects on crop growth, development and yield, little is known about the interactive effects of these two factors on cotton. The objective of this study was to determine the combined effects of elevated (CO2) and UV-B radiation on cotton growth and physiology under controlled environmental conditions. The four treatments imposed were control [360 μmol (CO2) mol-1 and 8 kJ m-2 d-1 UV-B], +CO2 [720 μmol (CO2) mol-1 and 8 kJ m-2 d-1 UV-B], +UV-B [360 μmol (CO2) mol-1 and 16 kJ m-2 d-1 UV-B] and +CO2+UV-B [720 μmol (CO2) mol-1 and 16 kJ m-2 d-1 UV-B]. Treatments were imposed from emergence through three weeks after the first flower stage. Plants grown in +CO2 showed greater plant height, leaf thickness, leaf area, leaf and canopy photosynthesis (PN) and total biomass compared to the control, and fruit biomass was not affected by +CO2 conditions. On the other hand, plants grown in +UV-B treatment exhibited slower growth as reflected by reduced plant height, shorter internodes and branch lengths, and total biomass due to smaller leaf areas and less lower leaf PN. The +UV-B treatment also altered the leaf morphology and significantly reduced flower and petal lengths and petal area. Reduction in fruit production under both +UV-B and +CO2+UV-B treatments was due to reduced photosynthesis and alterations in reproductive development. The results also showed interactive effects of UV-B on cotton leaf PN, phenolics, wax content and some physiological parameters measured. Thus, a failure to increase cotton fruit production with +CO2 and +CO2+UV-B suggests that breeding UV-B radiation-tolerant cultivars is important in both the present and future solar UV-B radiation environments.

  20. Impact of the Atmospheric Thickness on the Atmospheric Downwelling Longwave Radiation and Snowmelt under Clear-Sky Conditions in the Arctic and Subarctic.

    NASA Astrophysics Data System (ADS)

    Zhang, T.; Stamnes, K.; Bowling, S. A.

    2001-03-01

    Studies show that the energy available to melt snow at high latitudes is almost exclusively provided by radiation. Solar energy determines the period of possible snowmelt, while downwelling atmospheric longwave radiation modifies the timing and triggers the onset of snowmelt. Atmospheric thickness, defined as the vertical distance between the 500- and 1000-mb pressure surfaces, is directly related to the mean temperature and water vapor path of an atmospheric layer and thus has a direct influence on the downwelling longwave radiation and snowmelt. A comprehensive radiative transfer model was applied to calculate the downwelling longwave radiation to the snow surface over the period of snowmelt from 1980 through 1991 using radiosonde data obtained at Barrow and McGrath, Alaska, under clear-sky conditions. The results indicate that the atmospheric thickness has a positive impact on downwelling longwave radiation, which ranges from about 130 W m2 for an atmospheric thickness of 4850 m to about 280 W m2 for an atmospheric thickness of 5450 m. This study demonstrates that atmospheric water vapor path has a greater impact on atmospheric downwelling longwave radiation to the snow surface than the mean atmospheric temperature. This study also indicates that when the near-surface air temperature is used to infer downwelling longwave radiation, significant errors can occur. Thus, compared with the results obtained from the atmospheric radiative transfer model, the empirical formula due to Parkinson and Washington underestimates the downwelling longwave radiation when the near-surface air temperature is relatively high and overestimates it when the near-surface air temperature is relatively low. Investigations of the relationship between the atmospheric thickness and the snowmelt onset were conducted. Results indicate that for the period from 1980 through 1991, an atmospheric thickness of 5250 m at Barrow and 5200 m at McGrath in Alaska was sufficient to trigger the onset of

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. An Atmospheric Radiation and Cloud Station in the Tropical Western Pacific.

    NASA Astrophysics Data System (ADS)

    Mather, J. H.; Ackerman, T. P.; Clements, W. E.; Barnes, F. J.; Ivey, M. D.; Hatfield, L. D.; Reynolds, R. M.

    1998-04-01

    The interaction of clouds and radiation is a particularly difficult issue in the study of climate change. Clouds have a large impact on the earth's radiation budget but the range of spatial and temporal scales and the complexity of the physical processes associated with clouds made these interactions difficult to simulate. The Department of Energy's Atmospheric Radiation Measurement (ARM) program was established to improve the understanding of the interaction of radiation with the atmosphere with a particular emphasis on the effects of clouds. To continue its role of providing data for the study of these interactions, the ARM program deployed an Atmospheric Radiation and Cloud Station (ARCS) in the tropical western Pacific. This site began operation in October 1996. The tropical western Pacific is a very important climatic region. It is characterized by strong solar heating, high water vapor concentrations, and active convection. The ARCS is equipped with a comprehensive suite of instruments for measuring surface radiation fluxes and properties of the atmospheric state and is intended to operate for the next 10 years. The ARCS is an integrated unit that includes a data management system, a site monitor and control system, an external communications system, redundant electrical power systems, and containers that provide shelter for the equipment as well as work space for site operators, technicians, and visiting scientists. The dataset the ARCS produces will be invaluable in studying issues related to clouds and radiation in the Tropics. The site is located in Manus Province, Papua New Guinea, at 2.060°S, 147.425°E, 300 km north of the island of New Guinea. Two more ARCS are planned for deployment across the tropical Pacific.

  8. 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.

  9. A Simple Moist Tropical Atmosphere Model: The Role of Cloud Radiative Forcing.

    NASA Astrophysics Data System (ADS)

    Tian, Baijun; Ramanathan, V.

    2003-06-01

    A simple moist model for the large-scale tropical atmospheric circulation is constructed by combining the simple models of Gill and Neelin and Held. The model describes the first baroclinic mode of the moist troposphere with variable `gross moist stability' in response to given thermodynamic forcing from surface evaporation and atmospheric cloud radiative forcing (CRF), which is a measure of the radiative effects of clouds in the atmospheric radiative heating. When the present model is forced solely by the observed atmospheric CRF, quantitatively reasonable Hadley and Walker circulations are obtained, such as the trades, the ascending branches in the intertropical convergence zone (ITCZ) and the South Pacific Convergence Zone (SPCZ), as well as the descending branches in the cold tongue and subtropics. However, when the model is forced only by the observed surface evaporation, the Walker circulation totally disappears, and the Hadley circulation reverses. These results indicate that, in the context of a moist dynamic model, the spatial variations of atmospheric CRF are more important in terms of driving and maintaining the Hadley and Walker circulations than the spatial variation of surface evaporation.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

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

    SciTech Connect

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

    2000-08-03

    For improved safety in and around the ARM SGP CART site, the ARM Program recently purchased and installed an aircraft detection radar system at the central facility near Lamont, Oklahoma. The new system will enhance safety measures already in place at the central facility. The SGP CART site, especially the central facility, houses several instruments employing laser technology. These instruments are designed to be eye-safe and are not a hazard to personnel at the site or pilots of low-flying aircraft over the site. However, some of the specialized equipment brought to the central facility by visiting scientists during scheduled intensive observation periods (IOPs) might use higher-power laser beams that point skyward to make measurements of clouds or aerosols in the atmosphere. If these beams were to strike the eye of a person in an aircraft flying above the instrument, damage to the person's eyesight could result. During IOPs, CART site personnel have obtained Federal Aviation Administration (FAA) approval to temporarily close the airspace directly over the central facility and keep aircraft from flying into the path of the instrument's laser beam. Information about the blocked airspace is easily transmitted to commercial aircraft, but that does not guarantee that the airspace remains completely plane-free. For this reason, during IOPs in which non-eye-safe lasers were in use in the past, ARM technicians watched for low-flying aircraft in and around the airspace over the central facility. If the technicians spotted such an aircraft, they would manually trigger a safety shutter to block the laser beam's path skyward until the plane had cleared the area.

  16. 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. PMID:26151172

  17. 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.

  18. 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.

  19. 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.

  20. Interaction of a jet with a radiation pressure-dominated atmosphere - The case of SS 433

    NASA Technical Reports Server (NTRS)

    Arav, Nahum; Begelman, Mitchell C.

    1993-01-01

    A phenomenological model for the enigmatic object SS 433 is developed in which SS 433 is a neutron star (NS) surrounded by a dense accreted atmosphere. Jets are created close to the neutron star surface by the rapidly spinning NS, toward which matter flows at a super-Eddington rate. This supercritical accretion leads to a quasi-spherical atmosphere around the NS with very high pressure and density close to the surface. The interaction of the jet with the atmosphere as it propagates through it is discussed in detail. A boundary layer (BL) due to radiation viscosity forms between the jet and the surrounding medium. This BL can be visualized as a cocoon of low-density matter around the jet which prevents mass entrainment into the jet. A study of X-ray spectra shows how the radiation-viscous BL can explain the very small Delta v/v that is observed in the jets.

  1. 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.

  2. Top-of-atmosphere radiative cooling with white roofs: experimental verification and model-based evaluation

    NASA Astrophysics Data System (ADS)

    Salamanca, Francisco; Tonse, Shaheen; Menon, Surabi; Garg, Vishal; Singh, Krishna P.; Naja, Manish; Fischer, Marc L.

    2012-12-01

    We evaluate differences in clear-sky upwelling shortwave radiation reaching the top of the atmosphere in response to increasing the albedo of roof surfaces in an area of India with moderately high aerosol loading. Treated (painted white) and untreated (unpainted) roofs on two buildings in northeast India were analyzed on five cloudless days using radiometric imagery from the IKONOS satellite. Comparison of a radiative transfer model (RRTMG) and radiometric satellite observations shows good agreement (R2 = 0.927). Results show a mean increase of ˜50 W m-2 outgoing at the top of the atmosphere for each 0.1 increase of the albedo at the time of the observations and a strong dependence on atmospheric transmissivity.

  3. 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.

  4. 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.

  5. Advances in Understanding Top-of-Atmosphere Radiation Variability from Satellite Observations

    NASA Astrophysics Data System (ADS)

    Loeb, Norman G.; Kato, Seiji; Su, Wenying; Wong, Takmeng; Rose, Fred G.; Doelling, David R.; Norris, Joel R.; Huang, Xianglei

    2012-07-01

    This paper highlights how the emerging record of satellite observations from the Earth Observation System (EOS) and A-Train constellation are advancing our ability to more completely document and understand the underlying processes associated with variations in the Earth's top-of-atmosphere (TOA) radiation budget. Large-scale TOA radiation changes during the past decade are observed to be within 0.5 Wm-2 per decade based upon comparisons between Clouds and the Earth's Radiant Energy System (CERES) instruments aboard Terra and Aqua and other instruments. Tropical variations in emitted outgoing longwave (LW) radiation are found to closely track changes in the El Niño-Southern Oscillation (ENSO). During positive ENSO phase (El Niño), outgoing LW radiation increases, and decreases during the negative ENSO phase (La Niña). The coldest year during the last decade occurred in 2008, during which strong La Nina conditions persisted throughout most of the year. Atmospheric Infrared Sounder (AIRS) observations show that the lower temperatures extended throughout much of the troposphere for several months, resulting in a reduction in outgoing LW radiation and an increase in net incoming radiation. At the global scale, outgoing LW flux anomalies are partially compensated for by decreases in midlatitude cloud fraction and cloud height, as observed by Moderate Resolution Imaging Spectrometer and Multi-angle Imaging SpectroRadiometer, respectively. CERES data show that clouds have a net radiative warming influence during La Niña conditions and a net cooling influence during El Niño, but the magnitude of the anomalies varies greatly from one ENSO event to another. Regional cloud-radiation variations among several Terra and A-Train instruments show consistent patterns and exhibit marked fluctuations at monthly timescales in response to tropical atmosphere-ocean dynamical processes associated with ENSO and Madden-Julian Oscillation.

  6. 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

  7. Modeling radiation from the atmosphere of Io with Monte Carlo methods

    NASA Astrophysics Data System (ADS)

    Gratiy, Sergey

    Conflicting observations regarding the dominance of either sublimation or volcanism as the source of the atmosphere on Io and disparate reports on the extent of its spatial distribution and the absolute column abundance invite the development of detailed computational models capable of improving our understanding of Io's unique atmospheric structure and origin. To validate a global numerical model of Io's atmosphere against astronomical observations requires a 3-D spherical-shell radiative transfer (RT) code to simulate disk-resolved images and disk-integrated spectra from the ultraviolet to the infrared spectral region. In addition, comparison of simulated and astronomical observations provides important information to improve existing atmospheric models. In order to achieve this goal, a new 3-D spherical-shell forward/backward photon Monte Carlo code capable of simulating radiation from absorbing/emitting and scattering atmospheres with an underlying emitting and reflecting surface was developed. A new implementation of calculating atmospheric brightness in scattered sunlight is presented utilizing the notion of an "effective emission source" function. This allows for the accumulation of the scattered contribution along the entire path of a ray and the calculation of the atmospheric radiation when both scattered sunlight and thermal emission contribute to the observed radiation---which was not possible in previous models. A "polychromatic" algorithm was developed for application with the backward Monte Carlo method and was implemented in the code. It allows one to calculate radiative intensity at several wavelengths simultaneously, even when the scattering properties of the atmosphere are a function of wavelength. The application of the "polychromatic" method improves the computational efficiency because it reduces the number of photon bundles traced during the simulation. A 3-D gas dynamics model of Io's atmosphere, including both sublimation and volcanic

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Radiation exposure of civilian airline crew members and associated biological effects due to the atmospheric ionizing radiation environment.

    PubMed

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

    2001-01-01

    A study, currently in progress, on the radiation exposure and the associated biomedical effects due to the atmospheric ionizing radiation environment for the Italian civilian aviation flight personnel is sketched. After a presentation of the considered data sources, a description of the cohort is given, in terms of criteria for eligibility, and cohort construction, size and composition. Then the protocol for the Italian study is presented: the various ways of investigating the exposure and the health status of past and currently employed aircrew members and follow-up procedures are shown. An overview is given of the data management and processing philosophy with regards to flight routes, radiation dose evaluation along the flight path and exposure matrix building, as adopted in the Italian study. Potential side studies of interest are also shown. PMID:11780613

  14. 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.

  15. 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.

  16. First results from VIRTIS on Venus Express 2.Radiative transfer and atmospheric modelling

    NASA Astrophysics Data System (ADS)

    Drossart, P.; Piccioni, G.; Coradini, A.; Arnold, G.; Sémery, A.; Peter, G.; Cosi, M.; Pasqui, C.; Bézard, B.; Marinangeli, L.; Virtis Team

    The VIRTIS observations of Venus will provide information on various levels into the atmosphere The atmosphere above the cloud will be observed by Venus Express both on day and night side in solar reflection and thermal emission with different type of radiative transfer models adapted to the different atmospheric domains Limb observations are expected to give access to mesospheric CO 2 and CO emissions through fluorescence observations non-LTE modelling of CO 2 and CO bands will constrain the physical parameters of these layers Spectroscopy of the 4-5 micron range with VIRTIS-M and --H channels will give access to thermal structure retrieval and cloud structure at the 60-90 km altitude levels Finally the deeper atmospheric windows limited by CO 2 and H 2 O bands are accessible only in thermal emission on the night side The sounded levels at 2 3 1 7 mu m are limited respectively to 30-20 km altitude when at shorter wavelength 1 18 1 10 1 01 0 9 and 0 85 mu m the hot surface of Venus is seen through the scattering clouds Atmospheric modelling is therefore the key to decrypt the mysteries of Venus by ultimately removing atmospheric contributions to search for possible variations of surface emissivity Results on the different types of atmospheric contributions observed by VIRTIS will be shown if the Venus Express mission permits

  17. Effects of hydrodynamics and thermal radiation in the atmosphere after comet impacts

    NASA Technical Reports Server (NTRS)

    Nemchinov, I. V.; Popova, M. P.; Shubadeeva, L. P.; Shuvalov, V. V.; Svetsov, V. V.

    1993-01-01

    Radiation phenomena in the atmosphere after impacts of cosmic bodies have special features in comparison with the surface nuclear explosions. First, initial concentration of energy after the impact is lower, and second, a wake after the passage of the meteoroid through the atmosphere has a dramatic effect on the atmospheric flow and radiation transfer. Consequently, scaling laws can not be employed for prediction of the flow in the atmosphere and the light flux on the Earth's surface. If a density of high-velocity impactor is low relative to the ground, as in a case of a comet impact on rocks, a major part of the kinetic energy is converted to internal energy of dense hot vapors. But radiation effects can be essential even for fairly low velocities of the impactor. To clarify this issue we have undertaken calculations of 100-Mt explosions at the Earth's surface caused by small comets with velocities from 10 to 70 km/sec. That is, the initial concentration of energy has been varied. The calculations have shown that for velocities of the comet greater or about 20 km/sec a portion of energy emitted from the fireball exceeds 20% of the total energy of the explosion and this quantity does not change very much with the velocity. Other aspects of this investigation are discussed.

  18. 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

  19. 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.

  20. Contribution of Vacuum-Ultraviolet Transitions of Molecular Nitrogen to Radiative Heat Flux During Atmospheric Reentry

    NASA Astrophysics Data System (ADS)

    Liebhart, Heiko; Fertig, Markus; Herdrich, Georg; Fasoulas, Stefanos; Roser, Hans-Peter

    2011-02-01

    Within this work we investigate the radiative properties of molecular nitrogen with respect to the highly excited electronic states giving rise to radiative transitions occurring in the spectral range of Vacuum-Ultraviolet (VUV) radiation. This is done in order to shed light on the role of VUV radiation of molecular nitrogen in the radiative heat load encountered by a vessel during highspeed atmospheric reentry. The considered transitions bands are the Lyman - Birge - Hopfield (a1IIg - X1Σ+g ), Birge - Hopfield I (b1Πu - X1Σ+g ), Birge-Hopfield II(b Σu -X Σg ), Caroll - Yoshino (c'41Σ+u - X1Σ+g ), Worley - Jenkins (c31IIu - X1Σ+g ), Worley (o31IIu - X1Σ+g ), and e Σu - X Σg band. The approach to retrieve the relevant parameters for the line by line radiation simulation follows common methods of calculation, which are the re- construction of the potential energy function via the Rydberg-Klein-Rees (RKR) method and subsequently solving the correspond- ing radial Schrodinger equation. Absorption and emission spectra are then calculated for a known equilibrium test condition of air plasma to illustrate the contribution of the VUV transitions to the radiation. The influence of the VUV radiation on the heat load experienced by a reentry vehicle is illustrated with an exemplary CFD calculation.

  1. 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

  2. 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.

  3. 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

  4. Consistent sets of atmospheric lifetimes and radiative forcings on climate for CFC replacements: HCFCs and HFCs

    NASA Astrophysics Data System (ADS)

    Naik, Vaishali; Jain, Atul K.; Patten, Kenneth O.; Wuebbles, Donald J.

    2000-03-01

    Recognition of deleterious effects of chlorine and bromine on ozone and climate over the last several decades has resulted in international accords to halt the production of chlorine-containing chlorofluorocarbons (CFCs) and bromine-containing halons. It is well recognized, however, that these chemicals have had important uses to society, particularly as refrigerants, as solvents, as plastic blowing agents, as fire retardants and as aerosol propellants. This has led to an extensive search for substitute chemicals with appropriate properties to be used in place of the CFCs and halons. The purpose of this study is to evaluate in a consistent manner the atmospheric lifetime and radiative forcing on climate for a number of replacement compounds. The unique aspect of this study is its attempt to resolve inconsistencies in previous evaluations of atmospheric lifetimes and radiative forcings for these compounds by adopting a uniform approach. Using the latest version of our two-dimensional chemical-radiative-transport model of the global atmosphere, we have determined the atmospheric lifetimes of 28 hydrohalocarbons (HCFCs and HFCs). Through the comparison of the model-calculated lifetimes with lifetimes derived using a simple scaling method, our study adds to earlier findings that consideration of stratospheric losses is important in determining the lifetimes of gases. Discrepancies were found in the reported lifetimes of several replacement compounds reported in the international assessment of stratospheric ozone published by the World Meteorological Organization [Granier et al., 1999] and have been resolved. We have also derived the adjusted and instantaneous radiative forcings for CFC-11 and 20 other halocarbons using our radiative transfer model. The sensitivity of radiative forcings to the vertical distribution of these gases is investigated in this study and is shown to be significant. The difference in the global radiative forcing arising from the assumption of a

  5. 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.

  6. Internal gravity waves in the solar atmosphere. II - Effects of radiative damping

    NASA Technical Reports Server (NTRS)

    Mihalas, B. W.; Toomre, J.

    1982-01-01

    In the solar photosphere, temperature fluctuations associated with acoustic-gravity waves may be rapidly smoothed by the transfer mechanism of radiation between hotter and cooler regions. The present investigation of the radiative effects on internal gravity waves takes into account the parameterization of the radiative energy, employing the Newtonian cooling approximation. A linear analysis of the propagation of internal gravity waves is carried out in a model of the solar atmosphere which is taken to be homogeneous in the horizontal coordinates. Linear wave properties both with and without radiative cooling are summarized, and the variation with height of energy fluxes and of nonlinearities in the waves is discussed. Attention is given to the significance of the obtained results in terms of energy balance in the chromosphere and in relation to spectral line observations.

  7. 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.

  8. 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.

  9. 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.

  10. An iterative method for the solution of the statistical and radiative equilibrium equations in expanding atmospheres

    NASA Astrophysics Data System (ADS)

    Hillier, D. J.

    1990-05-01

    A method for the solution of the statistical equilibrium, and radiative equilibrium equations in spherical atmospheres is presented. The iterative scheme uses a tridiagonal (or pentadiagonal) Newton-Raphson operator, and is based on the complete linearization method of Auer and Mihalas (1969) but requires less memory, and imposes no limit on the number of transitions that can be treated. The method is also related to iterative techniques that use approximate diagonal lambda operators but it has a vastly superior convergence rate. Calculations of WN and WC model atmospheres illustrate the excellent rate of convergence.

  11. Climate variability and relationships between top-of-atmosphere radiation and temperatures on Earth

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Zhang, Yongxin; Fasullo, John T.; Taguchi, Shoichi

    2015-05-01

    The monthly global and regional variability in Earth's radiation balance is examined using correlations and regressions between atmospheric temperatures and water vapor with top-of-atmosphere outgoing longwave (OLR), absorbed shortwave (ASR), and net radiation (RT = ASR - OLR). Anomalous global mean monthly variability in the net radiation is surprisingly large, often more than ±1 W m-2, and arises mainly from clouds and transient weather systems. Relationships are strongest and positive between OLR and temperatures, especially over land for tropospheric temperatures, except in the deep tropics where high sea surface temperatures are associated with deep convection, high cold cloud tops and thus less OLR but also less ASR. Tropospheric vertically averaged temperatures (surface = 150 hPa) are thus negatively correlated globally with net radiation (-0.57), implying 2.18 ± 0.10 W m-2 extra net radiation to space for 1°C increase in temperature. Water vapor is positively correlated with tropospheric temperatures and thus also negatively correlated with net radiation; however, when the temperature dependency of water vapor is statistically removed, a significant positive feedback between water vapor and net radiation is revealed globally with 0.87 W m-2 less OLR to space per millimeter of total column water vapor. The regression coefficient between global RT and tropospheric temperature becomes -2.98 W m-2 K-1 if water vapor effects are removed, slightly less than expected from blackbody radiation (-3.2 W m-2 K-1), suggesting a positive feedback from clouds and other processes. Robust regional structures provide additional physical insights. The observational record is too short, weather noise too great, and forcing too small to make reliable estimates of climate sensitivity.

  12. Atmospheric Longwave Irradiance Uncertainty: Pyrgeometers Compared to an Absolute Sky-Scanning Radiometer, Atmospheric Emitted Radiance Interferometer, and Radiative Transfer Model Calculations

    SciTech Connect

    Philipona, J. R.; Dutton, Ellsworth G.; Stoffel, T.; Michalsky, Joseph J.; Reda, I.; Stifter, Armin; Wendling, Peter; Wood, Norm; Clough, Shepard A.; Mlawer, Eli J.; Anderson, Gail; Revercomb, Henry E.; Shippert, Timothy R.

    2001-06-04

    Because atmospheric longwave radiation is one of the most fundamental elements of an expected climate change, there has been a strong interest in improving measurements and model calculations in recent years. Important questions are how reliable and consistent are atmospheric longwave radiation measurements and calculations and what are the uncertainties? The First International Pyrgeometer and Absolute Sky-scanning Radiometer Comparison, which was held at the Atmospheric Radiation Measurement program's Souther Great Plains site in Oklahoma, answers these questions at least for midlatitude summer conditions and reflects the state of the art for atmospheric longwave radiation measurements and calculations. The 15 participating pyrgeometers were all calibration-traced standard instruments chosen from a broad international community. Two new chopped pyrgeometers also took part in the comparison. And absolute sky-scanning radiometer (ASR), which includes a pyroelectric detector and a reference blackbody source, was used for the first time as a reference standard instrument to field calibrate pyrgeometers during clear-sky nighttime measurements. Owner-provided and uniformly determined blackbody calibration factors were compared. Remarkable improvements and higher pyrgeometer precision were achieved with field calibration factors. Results of nighttime and daytime pyrgeometer precision and absolute uncertainty are presented for eight consecutive days of measurements, during which period downward longwave irradiance varied between 260 and 420 W m-2. Comparisons between pyrgeometers and the absolute ASR, the atmospheric emitted radiance interferometer, and radiative transfer models LBLRTM and MODTRAN show a surprisingly good agreement of <2 W m-2 for nighttime atmospheric longwave irradiance measurements and calculations.

  13. 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

  14. 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.

  15. Shortwave radiation interaction with highly patterned tundra vegetation and feedbacks to permafrost soil and atmosphere

    NASA Astrophysics Data System (ADS)

    Schaepman-Strub, G.; Erb, A.; Gurm, K.; Budishchev, A.

    2012-12-01

    Tundra vegetation is an important mediator of carbon, water, and energy fluxes between the permafrost soil and the atmosphere. Vegetation types and their feedbacks in arctic landscapes might however be highly dynamic in space and time. As an example, our NE Siberian research site is dominated by thawing ponds, wet sedge and dwarf shrub patches at the scale of a few meters. Shrubs are predicted to increase in density and height under climate change scenarios, with a related increase in absorbed shortwave radiation by the canopy, resulting in a positive feedback to climate warming. This study examines how shortwave radiation reflected to the atmosphere and transmitted to the ground is altered by shrub density and height. We present results based on a combination of manipulated plots, in situ spectral radiation and plant structural measurements, and a sophisticated 3D radiative transfer model to quantify the influence of shrubs on the shortwave energy budget. We will discuss non-linear dynamics in shortwave radiation partitioning at the land surface, with special emphasis on seasonality. Our results are relevant to test 1D assumptions in climate models and for species competition modelling.

  16. 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.

  17. 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.

  18. 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

  19. Radiative transfer codes for atmospheric correction and aerosol retrieval: intercomparison study.

    PubMed

    Kotchenova, Svetlana Y; Vermote, Eric F; Levy, Robert; Lyapustin, Alexei

    2008-05-01

    Results are summarized for a scientific project devoted to the comparison of four atmospheric radiative transfer codes incorporated into different satellite data processing algorithms, namely, 6SV1.1 (second simulation of a satellite signal in the solar spectrum, vector, version 1.1), RT3 (radiative transfer), MODTRAN (moderate resolution atmospheric transmittance and radiance code), and SHARM (spherical harmonics). The performance of the codes is tested against well-known benchmarks, such as Coulson's tabulated values and a Monte Carlo code. The influence of revealed differences on aerosol optical thickness and surface reflectance retrieval is estimated theoretically by using a simple mathematical approach. All information about the project can be found at http://rtcodes.ltdri.org. PMID:18449285

  20. 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.

  1. 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.

  2. 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.

  3. Observations of Black Carbon characteristics and radiative forcing over a Global Atmosphere Watch supersite in Korea

    NASA Astrophysics Data System (ADS)

    Panicker, A. S.; Park, Sung-Hwa; Lee, Dong-In; Kim, Dong-Chul; Jung, Woon-Seon; Jang, Sang-Min; Jeong, Jong-Hoon; Kim, Dong-Soon; Yu, Jegyu; Jeong, Harrison

    2013-10-01

    This paper provides an account of observed variations in Black carbon (BC) mass concentrations and BC induced radiative forcing for the first time over a background Global Atmosphere Watch (GAW) site, Anmyeon in South Korea. BC concentrations were continuously measured over the site during January 2003-December 2004 periods using an Aethalometer. BC showed higher concentrations during 2003 in majority of the months (except in January, August and October). BC found to be showing higher concentrations in September 2003, with values reaching up to 3 μg m-3 over the site. It also showed higher peaks in May and December in 2003. BC values were found to be comparatively less during wet season (July-August; especially august), which could be associated with the rainout and washout associated with the Changma season (summer monsoon). Optical Properties of Aerosols and Clouds (OPAC) model in combination with a radiative transfer model (SBDART) were used to estimate aerosol radiative forcing separately for composite aerosols (total aerosols) and solely for BC aerosols using chemical composition data sets of Total Suspended Particulates (TSP) and BC. The atmospheric forcing for composite aerosols found to be +14.9 to +25.9 W m-2 during spring, +13.4 to +20.4 W m-2 in summer, +12.9 to +19.1 W m-2 in autumn and +16 to +18.2 W m-2 during winter,respectively. The respective BC atmospheric forcings were +8.1 to +11.8 W m-2, +8.4 to +11.1 W m-2, +8.7 to +11.4 W m-2 and +8.8 to +11.7 W m-2 during spring, summer, autumn and winter. The study suggests that BC induced atmospheric forcing can contribute up to 88% of total aerosol induced atmospheric warming.

  4. 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).

  5. Extending radiative transfer models by use of Bayes rule. [in atmospheric science

    NASA Technical Reports Server (NTRS)

    Whitney, C.

    1977-01-01

    This paper presents a procedure that extends some existing radiative transfer modeling techniques to problems in atmospheric science where curvature and layering of the medium and dynamic range and angular resolution of the signal are important. Example problems include twilight and limb scan simulations. Techniques that are extended include successive orders of scattering, matrix operator, doubling, Gauss-Seidel iteration, discrete ordinates and spherical harmonics. The procedure for extending them is based on Bayes' rule from probability theory.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. How much does sea spray aerosol organic matter impact clouds and radiation? Sensitivity studies in the Community Atmosphere Model

    NASA Astrophysics Data System (ADS)

    Burrows, S. M.; Liu, X.; Elliott, S.; Easter, R. C.; Singh, B.; Rasch, P. J.

    2015-12-01

    Submicron marine aerosol particles are frequently observed to contain substantial fractions of organic material, hypothesized to enter the atmosphere as part of the primary sea spray aerosol formed through bubble bursting. This organic matter in sea spray aerosol may affect cloud condensation nuclei and ice nuclei concentrations in the atmosphere, particularly in remote marine regions. Members of our team have developed a new, mechanistic representation of the enrichment of sea spray aerosol with organic matter, the OCEANFILMS parameterization (Burrows et al., 2014). This new representation uses fields from an ocean biogeochemistry model to predict properties of the emitted aerosol. We have recently implemented the OCEANFILMS representation of sea spray aerosol composition into the Community Atmosphere Model (CAM), and performed sensitivity experiments and comparisons with alternate formulations. Early results from these sensitivity simulations will be shown, including impacts on aerosols, clouds, and radiation. References: Burrows, S. M., Ogunro, O., Frossard, A. A., Russell, L. M., Rasch, P. J., and Elliott, S. M.: A physically based framework for modeling the organic fractionation of sea spray aerosol from bubble film Langmuir equilibria, Atmos. Chem. Phys., 14, 13601-13629, doi:10.5194/acp-14-13601-2014, 2014.

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

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  14. 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.

  15. 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.

  16. 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.

  17. New Radiative Transfer Capability in the EPIC Atmospheric Model with Application to Saturn and Uranus

    NASA Astrophysics Data System (ADS)

    Dowling, Timothy Edward; Greathouse, T. K.; Sussman, M. G.; Chanover, N. J.

    2010-10-01

    We have adapted radiative transfer (RT) schemes from the gas-giant seasonal models of Greathouse et al. (EGU 2010) and Sussman et al. (AGU 2009) into the EPIC atmospheric model, and applied them to Saturn and Uranus. These additions give EPIC a hierarchy of RT options to account for solar heating via CH4 absorption from 5 microns to the UV, and radiative cooling due to thermal emission of CH4, C2H2, C2H6, and collision-induced opacity between 0 and 1600 cm-1. We have written an IDL tool to calculate radiative-equilibrium T(p) profiles for model initialization. We have ported the versatile DISORT RT model (Stamnes et al. 1988) from Fortran to C, and are incorporating it into an IDL post-processing tool to allow us to create synthetic spectra from EPIC output that accounts for thermal emission, reflected solar light, and aerosol and Rayleigh scattering. We give an update of applications to simulations of middle-atmosphere temperatures for Saturn and zonal-wind spin-up experiments for Uranus. This research is supported by NASA Planetary Atmospheres grant NNX08AE64G and NSF Planetary Astronomy grant AST-0807989.

  18. 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.

  19. Single-Column Modeling, GCM Parameterizations and Atmospheric Radiation Measurement Data

    SciTech Connect

    Somerville, R.C.J.; Iacobellis, S.F.

    2005-03-18

    Our overall goal is identical to that of the Atmospheric Radiation Measurement (ARM) Program: the development of new and improved parameterizations of cloud-radiation effects and related processes, using ARM data at all three ARM sites, and the implementation and testing of these parameterizations in global and regional models. To test recently developed prognostic parameterizations based on detailed cloud microphysics, we have first compared single-column model (SCM) output with ARM observations at the Southern Great Plains (SGP), North Slope of Alaska (NSA) and Topical Western Pacific (TWP) sites. We focus on the predicted cloud amounts and on a suite of radiative quantities strongly dependent on clouds, such as downwelling surface shortwave radiation. Our results demonstrate the superiority of parameterizations based on comprehensive treatments of cloud microphysics and cloud-radiative interactions. At the SGP and NSA sites, the SCM results simulate the ARM measurements well and are demonstrably more realistic than typical parameterizations found in conventional operational forecasting models. At the TWP site, the model performance depends strongly on details of the scheme, and the results of our diagnostic tests suggest ways to develop improved parameterizations better suited to simulating cloud-radiation interactions in the tropics generally. These advances have made it possible to take the next step and build on this progress, by incorporating our parameterization schemes in state-of-the-art 3D atmospheric models, and diagnosing and evaluating the results using independent data. Because the improved cloud-radiation results have been obtained largely via implementing detailed and physically comprehensive cloud microphysics, we anticipate that improved predictions of hydrologic cycle components, and hence of precipitation, may also be achievable. We are currently testing the performance of our ARM-based parameterizations in state-of-the--art global and regional

  20. 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).

  1. 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

  2. Macroscopic Models of Radiative Transfer as Applied to Computation of the Radiation Field in the Solar Atmosphere

    NASA Technical Reports Server (NTRS)

    Ripoll, J.-F.; Wray, A. A.

    2003-01-01

    In this paper a new three dimensional half-moment model for radiative transfer is presented for a gray medium. It describes the evolution of the zeroth and first directional half moments of the radiative intensity. The closure is provided, similarly to Dubroca and Klar, by the maximum entropy concept. This work generalizes that model to three dimensions. The model presented here (the derivation being done in Ripoll and Wray, called the M(sup 1/2)(sub 1) model, is a hyperbolic system consisting of a total of eight equations in three dimensions, four equations for each direction. Each half model has the classical form of a macroscopic moment model in which the pressure tensor is constructed from the well-known Eddington tensor with a particular Eddington factor. Moreover, different source and border terms occur. The latter introduce couplings between the macroscopic and microscopic quantities and between the + and - streams, through the intensity in the plane perpendicular to the flux. The main theoretical application of the half moment model, treated in this paper, is its reduction to a full moment model, called M(sup +)(sub 1), for the particular but important case of a hot, opaque source radiating in a cold transparent (or semi-transparent) medium for very specific applications, such as stellar interiors or atmospheres, or combustion problems. The structure of the paper is as follows. In section 2, the model M(sup 1/2)(sub 1) is presented. In section 3, for the particular case of a hot, opaque source radiating into a cold medium, the half moment model is reduced to the M(sup +)(sub 1) model. In section 4, we first solve a simple and academic problem to validate the models, followed by a simplified solar atmosphere.

  3. 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

  4. 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

  5. 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.

  6. Quantifying the relationships between precipitation and atmospheric radiative cooling on a range of scales

    NASA Astrophysics Data System (ADS)

    Naegele, A. C.; Randall, D. A.

    2014-12-01

    In the global energy budget, the radiative cooling of the atmosphere is approximately balanced by latent heating; this implies a positive temporal correlation between the globally averaged atmospheric radiative cooling rate (ARC) and the globally averaged precipitation rate. The high clouds associated with precipitating weather systems tend to reduce the ARC, and so act to damp fluctuations of the global hydrologic cycle. In contrast, on the regional scale, high clouds cause the precipitation rate and the ARC to be negatively correlated in both space and time. The radiative warming associated with the high clouds promotes regional-scale rising motion and so feeds back to enhance the regional precipitation rate. We have used precipitation data from the Global Precipitation Climatology Project and radiative flux data (used to calculate the ARC) from the Clouds and the Earth's Radiant Energy System (CERES) project to investigate the relationships between the ARC and the precipitation rate on a range of spatial and temporal scales. Results show that the ARC and the precipitation rate are positively correlated globally and in middle and high latitudes, and negatively correlated in the tropics.

  7. 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. PMID:25321700

  8. Stellar Winds and High-Energy Radiation: Evolution and influences on planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Johnstone, C.; Tu, L.; Güdel, M.; Lüftinger, T.; Lammer, H.; Kislyakova, K.; Fichtinger, B.

    2015-10-01

    As part of the Austrian research network "Pathways to Habitability: From Disks to Active Stars, Planets and Life" (path.univie.ac.at), we study the evolution of stellar output (e.g. winds, high-energy radiation) over the lifetimes of solar-like stars and the influence of stellar output on the development of habitable planetary environments. We have developed a coupled stellar rotation-wind-radiation model that describes the long term evolution of stellar output over the course of a star's life. We show that the initial rotation rate of a star can significantly influence the evolution of winds and high-energy radiation and therefore the development of planetary atmospheres.

  9. 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.

  10. Measurement and modeling of external radiation during 1984 from LAMPF atmospheric emissions

    SciTech Connect

    Bowen, B.M.; Olsen, W.A.; Van Etten, D.; Chen, I.

    1986-07-01

    An array of three portable, pressurized ionization chambers (PICs) measured short-term external radiation levels produced by air activation products from the Los Alamos Meson Physics Facility (LAMPF). The monitoring was at the closet offsite location, 700-900 m north and northeast of the source, and across a large, deep canyon. A Gaussian-type atmospheric dispersion model, using onsite meteorological and stack release data, was tested during their study. Monitoring results indicate that a persistent, local up-valley wind during the evening and early morning hours is largely responsible for causing the highest radiation levels to the northeast and north-northeast of LAMPF. Comparison of predicted and measured daily external radiation levels indicates a high degree of correlation. The model also gives accurate estimates of measured concentrations over longer periods of time.

  11. 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.

  12. 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.

  13. Solar radiation transport in the cloudy atmosphere: a 3D perspective on observations and climate impacts

    NASA Astrophysics Data System (ADS)

    Davis, Anthony B.; Marshak, Alexander

    2010-02-01

    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.

  14. 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.

  15. Soil moisture regime and soil type affect the decomposition of graminoid litter grown under three levels of atmospheric CO2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increases in atmospheric CO2 can augment the quantity and change the quality of plant carbon (C) inputs into grassland soils. Soil moisture interacts with substrate characteristics and soil properties to affect decomposition and transfer of plant-derived C into soil organic matter (SOM). Thus, pre...

  16. 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.

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

    SciTech Connect

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

    2000-02-27

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

  19. 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.

  20. 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

  1. 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

  2. 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...

  3. 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.

  4. Shortwave cloud-radiative forcing at the top of the atmosphere at the surface and of the atmospheric column as determined from ISCCP C1 data

    NASA Technical Reports Server (NTRS)

    Laszlo, Istvan; Pinker, Rachel T.

    1993-01-01

    The paper employs the C1 data of the International Satellite Cloud Climatology Project, along with the Satellite Algorithm for Shortwave Radiation Budget, to estimate the shortwave cloud effects in terms of the cloud-radiative forcing at the top of the atmosphere (TOA) and at the surface, and that of the atmospheric column on a global scale for the July months of 1983-1985. The cloud forcing for July 1985 is underestimated, by about 8/sq Wm, compared with that obtained from the Earth Radiation Budget Experiment. The cloud forcing at the surface is almost identical to that at the TOA, indicating that the effect of clouds on the shortwave energy budget of the surface-atmosphere system is such that most of the cooling is at the surface.

  5. 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.

  6. The Performance of Current Atmospheric Radiation Codes in Phase I of CIRC

    NASA Technical Reports Server (NTRS)

    Oreopoulos, L.; Mlawer, E.; Shippert, T.; Cole, J.; Fomin, B.; Iacono, M.; Jin, Z.; Li, J.; Manners, J.; Raisanen, P.; Rose, F.; Zhang, Y.; Wilson, M.; Rossow, W.

    2012-01-01

    The Continual Intercomparison of Radiation Codes (CIRC) is intended as an evolving and regularly updated reference source for evaluation of radiative transfer (RT) codes used in Global Climate Models and other atmospheric applications. In our presentation we will discuss our evaluation of the performance of 13 shortwave and 11 longwave RT codes that participated in Phase I of CIRC. CIRC differs from previous intercomparisons in that it relies on an observationally validated catalogue of cases. The seven CIRC Phase I baseline cases, five cloud-free, and two with overcast liquid clouds, are built around observations by the Atmospheric Radiation Measurements (ARM) program that satisfy the goals .of Phase I, namely to examine RT model performance in realistic, yet not overly complex, atmospheric conditions. Besides the seven baseline cases, additional idealized "subcases" are also examined to facilitate interpretation of model errors. We will quantify individual model performance with respect to reference line-by-line calculations, and will also highlight RT code behavior for conditions of doubled CO2 , aspects of utilizing a spectral specification of surface albedo, and the impact of the inclusion of scattering in the thermal infrared. Our analysis suggests that RT codes should work towards improving their calculation of diffuse shortwave flux, shortwave absorption, treatment of spectral surface albedo, and shortwave CO2 forcing. Despite practical difficulties in comparing our results to previous results by the Intercomparison of Radiation Codes in Climate Models (ICRCCM) conducted about 20 years ago, it appears that the current generation of RT codes do indeed perform better than the codes of the ICRCCM era. By enhancing the range of conditions under which participating codes are tested, future CIRC phases will hopefully allow even more rigorous examination of RT code performance.

  7. 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.

  8. 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

  9. Variability in Global Top-of-Atmosphere Shortwave Radiation Between 2000 and 2005

    NASA Technical Reports Server (NTRS)

    Loebe, Norman G.; Wielicki, Bruce A.; Rose, Fred G.; Doelling, David R.

    2007-01-01

    Measurements from various instruments and analysis techniques are used to directly compare changes in Earth-atmosphere shortwave (SW) top-of-atmosphere (TOA) radiation between 2000 and 2005. Included in the comparison are estimates of TOA reflectance variability from published ground-based Earthshine observations and from new satellite-based CERES, MODIS and ISCCP results. The ground-based Earthshine data show an order-of-magnitude more variability in annual mean SW TOA flux than either CERES or ISCCP, while ISCCP and CERES SW TOA flux variability is consistent to 40%. Most of the variability in CERES TOA flux is shown to be dominated by variations global cloud fraction, as observed using coincident CERES and MODIS data. Idealized Earthshine simulations of TOA SW radiation variability for a lunar-based observer show far less variability than the ground-based Earthshine observations, but are still a factor of 4-5 times more variable than global CERES SW TOA flux results. Furthermore, while CERES global albedos exhibit a well-defined seasonal cycle each year, the seasonal cycle in the lunar Earthshine reflectance simulations is highly variable and out-of-phase from one year to the next. Radiative transfer model (RTM) approaches that use imager cloud and aerosol retrievals reproduce most of the change in SW TOA radiation observed in broadband CERES data. However, assumptions used to represent the spectral properties of the atmosphere, clouds, aerosols and surface in the RTM calculations can introduce significant uncertainties in annual mean changes in regional and global SW TOA flux.

  10. 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.

  11. 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.

  12. On Sensitivity of Spectral Radiative Fluxes to Atmospheric Water Vapor in the 940 nm Region (Numerical Simulation)

    SciTech Connect

    Zhuravleva, T.B.; Firsov, K.M.

    2005-03-18

    Water vapor is well known to be a critical component in many aspects of atmospheric research, such as radiative transfer and cloud and aerosol processes. This requires both improved measurements of the columnar water vapor and its profiles in the atmosphere in a wide range of conditions, and adjustment of water vapor parameterizations in radiation codes including the perfection of spectroscopic parameters. In this paper we will present the results of comparison of our calculations and downward solar fluxes measured with Rotating Shadowband Spectroradiometer under conditions of horizontally homogeneous clouds. We also will discuss the sensitivity of atmospheric radiation characteristics to variations of water vapor in the band 940 nm: these results may be useful for development of new methods of retrieval of the total column water vapor content (WVC) in the atmosphere from data of radiation observations.

  13. Influence of modified atmosphere packaging on radiation tolerance in the phytosanitary pest melon fly, Bactrocera cucurbitae (Diptera Tephritidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modified atmosphere packaging (MAP) producing a low oxygen environment to increase produce shelf life may increase the radiation tolerance of insect pests receiving phytosanitary irradiation treatment on traded agricultural commodities. Melon fly, Bactrocera cucurbitae (Diptera: Tephritidae) is an i...

  14. An Evaluation of the Nonlinearity Correction Applied to Atmospheric Emitted Radiance Interferometer (AERI) Data Collected by the Atmospheric Radiation Measurement Program

    SciTech Connect

    Turner, D. D.; Knuteson, R. O.; Revercomb, H. E.; Dedecker, R. G.; Feltz, W. F.

    2004-09-01

    Mercury Cadmium Telluride (MCT) detectors provide excellent sensitivity to infrared radiation and are used in passive infrared remote sensors such as the Atmospheric Emitted Radiance Interferometer (AERI). However, MCT detectors have a nonlinear response and thus this nonlinearity must be characterized and corrected to provide accurate infrared radiance observations. This paper discusses the significance of the nonlinearity correction applied to AERI data and its impacts on the parameters retrieved from the AERI spectra. It also evaluates the accuracy of the scheme used to determine the nonlinearity of the MCT detectors used in the Atmospheric Radiation Measurement (ARM) Program’s AERIs.

  15. 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

  16. 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.

  17. 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

  18. Top-of-Atmosphere Radiative Cooling with White Roofs: Experimental Verification and Model-based Evaluation

    NASA Astrophysics Data System (ADS)

    Salamanca, F.; Tonse, S.; Menon, S.; Garg, V.; Singh, K.; Naja, M. K.; Fischer, M. L.

    2012-12-01

    We evaluate differences in clear-sky upwelling shortwave radiation reaching the top of the atmosphere in response to increasing the reflectance of roof surfaces in an area of India with moderately high aerosol loading. Treated (painted white) and untreated (unpainted) roofs on two buildings in northeast India were analyzed on five cloudless days using radiometric imagery from the IKONOS satellite. Comparison of a radiative transfer model (RRTMG) and radiometric satellite observations shows good agreement (R2 = 0.927). Results show a mean increase of ~50 Wm-2 outgoing at the top of the atmosphere for each 0.1 increase of the albedo at the time of the observations and a strong dependence on atmospheric transmisivity. True color image of light (PW1, PW2) and dark (PD1, PD2) roofs at the Pantnagar site taken the 21st OCT 2011. The roof labeled PD2 is considerably more reflective than PD1 but less reflective than PW2 DNs for the NIR band at Pantnagar roofs PW1 (higher values in green) and PD1 (lower-valued dark blue pixels below and right of PW1)

  19. A new look at decoupling of atmospheric radiative transfer and anisotropic surface reflection

    NASA Astrophysics Data System (ADS)

    Radkevich, Alexander

    2013-09-01

    This paper presents a new approach for separating atmospheric radiative transport from the lower boundary condition in the case of one-dimensional problem. The approach allows for an exact analytical expression of the solution for an arbitrary surface reflectance. The solution has the form of linear combination of the standard problem solutions with illumination from both top and bottom of the atmosphere. The problem with illumination from below can be solved with existing radiative transfer codes by reversing the order of the atmospheric layers. The solutions for illumination from below are weighted with a surface resolving kernel that is specific for every lower boundary condition. The surface resolving kernel is defined by an integral equation of the Fredholm type. The solution for the Lambertian surface is also obtained in the framework of this approach. Different methods of solution for the surface resolving kernel are considered. The successive iterations of the integral equation for the surface resolving kernel are equivalent to the decomposition of the surface reflected radiance by the orders of reflection. Recipes for the cases when standard problems are solved with the methods of discrete ordinates and spherical harmonics are also considered.

  20. Estimation of photosynthetically available radiation (PAR) from OCEANSAT-I OCM using a simple atmospheric radiative transfer model

    NASA Astrophysics Data System (ADS)

    Tripathy, Madhumita; Raman, Mini; Chauhan, Prakash

    2015-10-01

    Photosynthetically available radiation (PAR) is an important variable for radiation budget, marine and terrestrial ecosystem models. OCEANSAT-1 Ocean Color Monitor (OCM) PAR was estimated using two different methods under both clear and cloudy sky conditions. In the first approach, aerosol optical depth (AOD) and cloud optical depth (COD) were estimated from OCEANSAT-1 OCM TOA (top-of-atmosphere) radiance data on a pixel by pixel basis and PAR was estimated from extraterrestrial solar flux for fifteen spectral bands using a radiative transfer model. The second approach used TOA radiances measured by OCM in the PAR spectral range to compute PAR. This approach also included surface albedo and cloud albedo as inputs. Comparison between OCEANSAT-1 OCM PAR at noon with in situ measured PAR shows that root mean square difference was 5.82% for the method I and 7.24% for the method II in daily time scales. Results indicate that methodology adopted to estimate PAR from OCEANSAT-1 OCM can produce reasonably accurate PAR estimates over the tropical Indian Ocean region. This approach can be extended to OCEANSAT-2 OCM and future OCEANSAT-3 OCM data for operational estimation of PAR for regional marine ecosystem applications.

  1. Features of the flux of gamma-radiation in the lower atmosphere during precipitation

    NASA Astrophysics Data System (ADS)

    Germanenko, A. V.; Balabin, Yu V.; Gvozdevsky, B. B.; Vashenyuk, E. V.

    2013-02-01

    We are carrying out observations and studies of increases of gamma radiation intensity in a ground atmosphere layer during precipitations. Measurements have been carried out in two high-altitude points: Apatity (Murmansk) and Barentsburg (Spitsbergen). Scintillation detectors on the basis of NaI(Tl) crystals are used. Continuous radiation detection is made as the count rate in integral channels with threshold values >20 keV, >100 keV. There are more than 500 events of increase in gamma-ray background during precipitation. Average profiles of X-ray radiation increases in a ground level and the related with them increases of intensity of precipitations for stations in Apatity and Barentsburg have been built up. In Apatity the average increase profile in the gamma-ray flux and accompanying with profile of precipitations rate have been obtained. A time gap between peaks of precipitation and increase one is 30-40 minutes. A barometric coefficient of each component of radiation has been calculated. The barometric coefficient has a zero value on gamma-ray. The charged component of the secondary cosmic rays has a typical value ~0.18 %/mB. The lack of the barometric effect on gamma-ray indicates on the local origin of this radiation.

  2. Retrieval of atmospheric parameters and radiative properties using Far-Infrared remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Jamali, Maryam; Milz, Mathias; Martín-Torres, Javier; Palchetti, Luca

    2016-04-01

    The far-infrared (FIR) spectral region, covering wavelengths between 15 μm (667 cm‑1) and about 1 μm (10,000 cm‑1) plays a critical role in the climate system. A good knowledge of the radiation processes in this spectral region is of high interest for observations and understanding of heating and cooling rates, and global energy balance. Even though approximately 50% of terrestrial radiation occurs in the FIR and despite the critical FIR contribution to the Earth's energy balance, this spectral region has been only studied by a few number of instruments. Also the full FIR spectral region has not ever been directly observed from space. High spectral resolution observations in this region can help to enlighten its role for the global energy budget and atmospheric radiation processes. Among others, the reasons for this lack of measurements are: (i) the decreasing intensity of the radiation towards longer wavelengths; and, then (ii) the high sensitivity and cooling of the detectors requirements. These requirements are now overcome and future space missions will have the capability to measure the full FIR and then open fully one-half of the Earth's spectrum, and accordingly improve our ability to model and assess climate processes. The aim of the study is to assess the use of FIR remote sensing instruments for retrievals of atmospheric parameters and radiative properties such as heating and cooling rates. Case studies with simulated spectra, together with ground based measurements in the FIR at Dome C over the Antarctic Plateau at 3,230 m a.s.l. (above sea level) in clear-sky conditions, which been observed almost continuously since 2012, are used to assess the potential of remote sensing instruments in the far-infrared region. Appropriate selection of spectral channels to directly measure the far-infrared spectra as needed for future space missions and recommended.

  3. Modeling atmospheric longwave radiation at the surface during overcast skies: The role of cloud base height

    NASA Astrophysics Data System (ADS)

    Viúdez-Mora, A.; Costa-Surós, M.; Calbó, J.; González, J. A.

    2015-01-01

    behavior of the atmospheric downward longwave radiation at the surface under overcast conditions is studied. For optically thick clouds, longwave radiation depends greatly on the cloud base height (CBH), besides temperature and water vapor profiles. The CBH determines the cloud emission temperature and the air layers contributing to the longwave radiation that reaches the surface. Overcast situations observed at Girona (NE Iberian Peninsula) were studied by using a radiative transfer model. The data set includes different seasons, and a large range of CBH (0-5000 m). The atmosphere profiles were taken from the European Center for Medium-Range Weather Forecast analysis. The CBH was determined from ceilometer measurements and also estimated by using a suitable method applied to the vertical profile of relative humidity. The agreement between calculations and pyrgeometer measurements is remarkably good (1.6 ± 6.2 W m-2) if the observed CBH is used; poorer results are obtained with the estimated CBH (4.3 ± 7.0 W m-2). These results are better than those obtained from a simple parameterization based upon ground-level data (1.1 ± 11.6 W m-2), which can be corrected by adding a term that takes into account the CBH (-0.1 ± 7.3 W m-2). At this site, the cloud radiative effect (CRE) at the surface lies in the range 50-80 W m-2, has a clear seasonal behavior (higher CRE in winter), and depends upon the CBH. For the cold and the warm seasons, CRE decreases with CBH at a rate of -5 and -4 W m-2/km, respectively. Results obtained for other climates (subarctic and tropical) are also presented.

  4. 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.

  5. 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

  6. 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.

  7. Radiative Transfer in the Atmosphere Ocean System: The Finite-Element Method

    NASA Astrophysics Data System (ADS)

    Bulgarelli, Barbara; Kisselev, Viatcheslav B.; Roberti, Laura

    1999-03-01

    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.

  8. 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.

  9. Monitoring Top-of-Atmosphere Radiative Energy Imbalance for Climate Prediction

    NASA Technical Reports Server (NTRS)

    Lin, Bing; Chambers, Lin H.; Stackhouse, Paul W., Jr.; Minnis, Patrick

    2009-01-01

    Large climate feedback uncertainties limit the prediction accuracy of the Earth s future climate with an increased CO2 atmosphere. One potential to reduce the feedback uncertainties using satellite observations of top-of-atmosphere (TOA) radiative energy imbalance is explored. Instead of solving the initial condition problem in previous energy balance analysis, current study focuses on the boundary condition problem with further considerations on climate system memory and deep ocean heat transport, which is more applicable for the climate. Along with surface temperature measurements of the present climate, the climate feedbacks are obtained based on the constraints of the TOA radiation imbalance. Comparing to the feedback factor of 3.3 W/sq m/K of the neutral climate system, the estimated feedback factor for the current climate system ranges from -1.3 to -1.0 W/sq m/K with an uncertainty of +/-0.26 W/sq m/K. That is, a positive climate feedback is found because of the measured TOA net radiative heating (0.85 W/sq m) to the climate system. The uncertainty is caused by the uncertainties in the climate memory length. The estimated time constant of the climate is large (70 to approx. 120 years), implying that the climate is not in an equilibrium state under the increasing CO2 forcing in the last century.

  10. 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

  11. GEOLOGIC AND ATMOSPHERIC INPUT FACTORS AFFECTING WATERSHED CHEMISTRY IN UPPER MICHIGAN

    EPA Science Inventory

    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 neutraliza...

  12. 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.

  13. 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. PMID:24426044

  14. A global average model of atmospheric aerosols for radiative transfer calculations

    NASA Technical Reports Server (NTRS)

    Toon, O. B.; Pollack, J. B.

    1976-01-01

    A global average model is proposed for the size distribution, chemical composition, and optical thickness of stratospheric and tropospheric aerosols. This aerosol model is designed to specify the input parameters to global average radiative transfer calculations which assume the atmosphere is horizontally homogeneous. The model subdivides the atmosphere at multiples of 3 km, where the surface layer extends from the ground to 3 km, the upper troposphere from 3 to 12 km, and the stratosphere from 12 to 45 km. A list of assumptions made in construction of the model is presented and discussed along with major model uncertainties. The stratospheric aerosol is modeled as a liquid mixture of 75% H2SO4 and 25% H2O, while the tropospheric aerosol consists of 60% sulfate and 40% soil particles above 3 km and of 50% sulfate, 35% soil particles, and 15% sea salt below 3 km. Implications and consistency of the model are discussed.

  15. 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.

  16. Radiative transfer modeling in the coupled atmosphere- ocean system and its application to the remote sensing of ocean color imagery

    NASA Astrophysics Data System (ADS)

    Yan, Banghua

    2001-12-01

    Ocean color is the radiance emanating from the ocean due to scattering by chlorophyll pigments and particles of organic and inorganic origin. Thus, it contains information about chlorophyll concentrations which can be used to estimate primary productivity. Observations of ocean color from space can be used to monitor the variability in marine primary productivity, thereby permitting a quantum leap in our understanding of oceanographic processes from regional to global scales. Satellite remote sensing of ocean color requires accurate removal of the contribution by atmospheric molecules and aerosols to the radiance measured at the top of the atmosphere (TOA). This removal process is called ``atmospheric correction''. Since about 90% of the radiance received by the satellite sensor comes from the atmosphere, accurate removal of this portion is very important. A prerequisite for accurate atmospheric correction is accurate and reliable simulation of the transport of radiation in the atmosphere-ocean system. This thesis focuses on this radiative transfer process, and investigates the impact of particles in the atmosphere (aerosols) and ocean (oceanic chlorophylls and air bubbles) on our ability to remove the atmospheric contribution from the received signal. To explore these issues, a comprehensive radiative transfer model for the coupled atmosphere-ocean system is used to simulate the radiative transfer process and provide a physically sound link between surface-based measurements of oceanic and atmospheric parameters and radiances observed by satellite-deployed ocean color sensors. This model has been upgraded to provide accurate radiances in arbitrary directions as required to analyze satellite data. The model is then applied to quantify the uncertainties associated with several commonly made assumptions invoked in atmospheric correction algorithms. Since atmospheric aerosols consist of a mixture of absorbing and non- absorbing components that may or may not be

  17. Contribution for Iron Vapor and Radiation Distribution Affected by Current Frequency of Pulsed Arc

    NASA Astrophysics Data System (ADS)

    Shimokura, Takuya; Mori, Yusuke; Iwao, Toru; Yumoto, Motoshige

    Pulsed GTA welding has been used for improvement of stability, weld speed, and heat input control. However, the temperature and radiation power of the pulsed arc have not been elucidated. Furthermore, arc contamination by metal vapor changes the arc characteristics, e.g. by increasing radiation power. In this case, the metal vapor in pulsed GTA welding changes the distribution of temperature and radiation power as a function of time. This paper presents the relation between metal vapor and radiation power at different pulse frequencies. We calculate the Fe vapor distribution of the pulsed current. Results show that the Fe vapor is transported at fast arc velocity during the peak current period. During the base current period, the Fe vapor concentration is low and distribution is diffuse. The transition of Fe vapor distribution does not follow the pulsed current; the radiation power density distribution differs for high frequencies and low frequencies. In addition, the Fe vapor and radiation distribution are affected by the pulsed arc current frequency.

  18. 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.

  19. 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.

  20. Radiation and temperature effects of the intensive injection of dust aerosol into the atmosphere

    NASA Astrophysics Data System (ADS)

    Gorchakova, I. A.; Mokhov, I. I.; Rublev, A. N.

    2015-03-01

    Based on the measurements at the AERONET station (Ilorin, Nigeria), quantitative estimates of radiation and temperature effects of dust aerosol during the intensive sand storm in the Sahara Desert from January 28 to February 6, 2000, are obtained. The model used in calculations implies particles of dust aerosol being no more than 15 μm in radius (according to the data from AERONET station); another model takes into account large particles (LPs) up to 60 μm in radius and involves a spectral variation in the OPAC refraction index. In the short infrared region, the optical thickness of aerosol weakening increases with LPs taken into account in the aerosol model; the albedo of aerosol single scattering reduces in comparison to the respective optical parameters of the first model. Dust aerosol cools the earth's surface. In the presence of LPs in dust aerosol, the surface-atmosphere system can both cool and warm, while if LPs less than 15 μm in size are not taken into account, the surface cools. The rate of cooling of the 10-m near-surface atmospheric layer Δ T/Δ t changes in the interval of -(4-21)°C/day without the influence of LPs over 15 μm in size on solar radiation transfer taken into account; if this influence is taken into account, the rate is -(6-36)°C/day. In the long infrared region, the surface-atmosphere system warms more intensively if LPs are taken into account by the aerosol model. The heating rate of the 10-m near-surface atmospheric layer does not exceed ~0.5°C/day during the entire period of dust emission without LPs taken into account (AERONET algorithm); if LPs are taken into account (modeling results), heating rate reaches a maximal value of ~0.6°C/day.

  1. 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

  2. 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

  3. 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

  4. User interface development and metadata considerations for the Atmospheric Radiation Measurement (ARM) archive

    NASA Technical Reports Server (NTRS)

    Singley, P. T.; Bell, J. D.; Daugherty, P. F.; Hubbs, C. A.; Tuggle, J. G.

    1993-01-01

    This paper will discuss user interface development and the structure and use of metadata for the Atmospheric Radiation Measurement (ARM) Archive. The ARM Archive, located at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, is the data repository for the U.S. Department of Energy's (DOE's) ARM Project. After a short description of the ARM Project and the ARM Archive's role, we will consider the philosophy and goals, constraints, and prototype implementation of the user interface for the archive. We will also describe the metadata that are stored at the archive and support the user interface.

  5. 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

  6. Atmospheric attenuation of solar radiation and calibration of multiple wavelength sun photometers

    SciTech Connect

    Price, D.M.; Mulholland, G.P.; Matthews, L.K.; King, D.L.

    1986-01-01

    The activities detailed in this report include a review of the literature pertaining to the atmospheric attenuation of solar radiation, the maintenance and calibration of Volz and Sandia designed sun photometers, a comparison of the SOLTRAN5 and LOW-TRAN6 spectral irradiance models, an evaluation of the Li-Cor LI-1800 spectral radiometer, and a comparison between Li-Cor measurements of solar spectral irradiance and the modeled results from LOWTRAN6. Suggestions for the improvement of the sun photometers and the Li-Cor are also given.

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

    SciTech Connect

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

    1996-11-01

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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Reverse electric field Monte Carlo simulation for vector radiative transfer in the atmosphere

    NASA Astrophysics Data System (ADS)

    Li, Xu-You; Sun, Bo; Yu, Ying-Ying

    2014-06-01

    In this paper, a reverse electric field Monte Carlo (REMC) method is proposed to study the vector radiation transfer in the atmosphere. The REMC is based on tracing the multiply scattered electric field to simulate the vector transmitted radiance. The reflected intensities with different total optical depth values are obtained, which accord well with the results in the previous research. Stokes vector and the degree of polarization are numerically investigated. The simulation result shows that when the solar zenith angle is determined, the zenith angle of detector has two points, of which the degree of polarization does not change with the ground albedo and the optical depth. The two points change regularly with the solar zenith angle. Moreover, our REMC method can be applied to the vector radiative transfer in the atmosphere—ocean system.

  14. 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.

  15. 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.

  16. 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.

  17. Cloud-radiation feedback and atmosphere-ocean coupling in a stochastic multicloud model

    NASA Astrophysics Data System (ADS)

    Frenkel, Yevgeniy; Majda, Andrew J.; Stechmann, Samuel N.

    2015-09-01

    Despite recent advances in supercomputing, current general circulation models (GCMs) have significant problems in representing the variability associated with organized tropical convection. Furthermore, due to high sensitivity of the simulations to the cloud radiation feedback, the tropical convection remains a major source of uncertainty in long-term weather and climate forecasts. In a series of recent studies, it has been shown, in paradigm two-baroclinic-mode systems and in aquaplanet GCMs, that a stochastic multicloud convective parameterization based on three cloud types (congestus, deep and stratiform) can be used to improve the variability and the dynamical structure of tropical convection, including intermittent coherent structures such as synoptic and mesoscale convective systems. Here, the stochastic multicloud model is modified with a parameterized cloud radiation feedback mechanism and atmosphere-ocean coupling. The radiative convective feedback mechanism is shown to increase the mean and variability of the Walker circulation. The corresponding intensification of the circulation is associated with propagating synoptic scale systems originating inside of the enhanced sea surface temperature area. In column simulations, the atmosphere ocean coupling introduces pronounced low frequency convective features on the time scale associated with the depth of the mixed ocean layer. However, in the presence of the gravity wave mixing of spatially extended simulations, these features are not as prominent. This highlights the deficiency of the column model approach at predicting the behavior of multiscale spatially extended systems. Overall, the study develops a systematic framework for incorporating parameterized radiative cloud feedback and ocean coupling which may be used to improve representation of intraseasonal and seasonal variability in GCMs.

  18. Dust aerosol radiative effect and influence on urban atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Chen, M.; Li, L.

    2007-11-01

    An 1.5-level-closure and 3-D non-stationary atmospheric boundary layer (ABL) model and a radiation transfer model with the output of Weather Research and Forecast (WRF) Model and lidar AML-1 are employed to simulate the dust aerosol radiative effect and its influence on ABL in Beijing for the period of 23-26 January 2002 when a dust storm occurred. The simulation shows that daytime dust aerosol radiative effect heats up the ABL at the mean rate of about 0.68 K/h. The horizontal wind speed from ground to 900 m layer is also overall increased, and the value changes about 0.01 m/s at 14:00 LT near the ground. At night, the dust aerosol radiative effect cools the ABL at the mean rate of -0.21 K/h and the wind speed lowers down at about -0.19 m/s at 02:00 LT near the ground.

  19. 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.

  20. 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

  1. 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.

  2. Infrared Radiative Forcing and Atmospheric Lifetimes of Trace Species Based on Observations from UARS

    NASA Technical Reports Server (NTRS)

    Minschwaner, K.; Carver, R. W.; Briegleb, B. P.

    1997-01-01

    Observations from instruments on the Upper Atmosphere Research Satellite (UARS) have been used to constrain calculations of infrared radiative forcing by CH4, CCl2F2 and N2O, and to determine lifetimes Of CCl2F2 and N2O- Radiative forcing is calculated as a change in net infrared flux at the tropopause that results from an increase in trace gas amount from pre-industrial (1750) to contemporary (1992) times. Latitudinal and seasonal variations are considered explicitly, using distributions of trace gases and temperature in the stratosphere from UARS measurements and seasonally averaged cloud statistics from the International Satellite Cloud Climatology Project. Top-of-atmosphere fluxes calculated for the contemporary period are in good agreement with satellite measurements from the Earth Radiation Budget Experiment. Globally averaged values of the radiative forcing are 0.536, 0.125, and 0.108 W m-2 for CH4, CCl2F2, and N2O, respectively. The largest forcing occurs near subtropical latitudes during summer, predominantly as a result of the combination of cloud-free skies and a high, cold tropopause. Clouds are found to play a significant role in regulating infrared forcing, reducing the magnitude of the forcing by 30-40% compared to the case of clear skies. The vertical profile of CCl2F2 is important in determining its radiative forcing; use of a height-independent mixing ratio in the stratosphere leads to an over prediction of the forcing by 10%. The impact of stratospheric profiles on radiative forcing by CH4 and N2O is less than 2%. UARS-based distributions of CCl2F2 and N2O are used also to determine global destruction rates and instantaneous lifetimes of these gases. Rates of photolytic destruction in the stratosphere are calculated using solar ultraviolet irradiances measured on UARS and a line-by-line model of absorption in the oxygen Schumann-Runge bands. Lifetimes are 114 +/- 22 and 118 +/- 25 years for CCl2F2 and N2O, respectively.

  3. 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

  4. 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

  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. 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

  7. Relationship between the longwave cloud radiative forcing at the surface and the top of the atmosphere

    NASA Technical Reports Server (NTRS)

    HARSHVARDHAN; Randall, David A.; Dazlich, Donald A.

    1990-01-01

    An analysis is presented which suggests a technique that may be able to circumvent the problem of mapping the global longwave surface radiation budget from space in the presence of clouds. A theoretical framework is given that avoids the explicit computation of cloud fraction and the location of cloud base. It is found that in regions where a particular cloud regime exists preferentially, a relationship between the mean long range cloud radiative forcing (CRF) at the top of the atmosphere and at the surface can be shown to exist. Results from a general circulation model suggest that this relationship for monthly means is coherent over fairly large geographical areas. For example, in tropical convective areas, the longwave CRF at the top is very large, but at the surface it is quite small because of the high opacity of the lowest layers of the atmosphere. It is also found that, in areas of stratus over cool ocean surfaces, the longwave CRF at the top is very small but at the surface it is quite substantial.

  8. 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.

  9. Temporal indications of atmospheric stability affecting off-target spray drift in the midsouth U S

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to determine atmospheric conditions favorable for long-distance spray drift deleterious to susceptible crops. A tall meteorological monitoring tower equipped with six precision (and periodically calibrated) thermistors at six heights to 27.4 m and wind speed anemometers at fo...

  10. 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 (...

  11. Atmospheric Downwelling Longwave Radiation during overcast conditions. Simulations and measurements at Girona, Spain.

    NASA Astrophysics Data System (ADS)

    Viúdez, Toni; Calbó, Josep; Abel González, Josep; Jiménez, M. Antonia

    2010-05-01

    Clouds play an important role in the terrestrial radiative budget and therefore in the climate change, given their ability to absorb solar radiation and also to absorb and emit longwave radiation toward the space and the terrestrial surface. The study of longwave radiation in presence of clouds can help us to understand better the climatic system, and recognize their importance in the current climate change. Agreement between measurements and simulations can help us to understand much better their radiative behavior. In this study we show a comparison between measurements and calculations using the unidimensional radiative transfer model SBDART (Ricchiazzi et al, 1998) under overcast sky conditions. Measurements were taken from the radiometric and meteorological station at the University of Girona, Spain (41.96 N 2.83 E 110 m a.s.l.). Downward Longwave Radiation, DLR, was measured using a pyrgeometer CG1 by Kipp & Zonen. To determine the cloud fraction, and subsequently select overcast cases, we used the algorithm APCADA (Dürr and Philipona, 2004) from one year dataset of measurements of DLR, temperature and relative humidity. DLR has a strong dependence on atmospheric vertical profiles (mainly on temperature and water vapor content). Since there are no soundings available at the same site, we used the vertical profile from a gridded analysis (provided by the European Centre for Medium-Range Weather Forecasts,ECMWF). Cloud base height (CBH) was included into calculations by using the measurements taken by a ceilometer CL31 by Vaisala. This CBH was compared with an estimation based on ECMWF profiles, setting the cloud base where the relative humidity is higher than a threshold of 95% (RH95). The effective radius of cloud droplets and liquid water path was fixed from typical values (Stephens, 1978). Three different modeling cases were analyzed, depending on the use of the CBH from the ceilometer or from applying the RH95 threshold in ECMWF profiles, and also

  12. 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

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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).

  20. The thermal structure of the atmospheric surface boundary layer on Mars as modified by the radiative effect of aeolian dust

    NASA Technical Reports Server (NTRS)

    Pallmann, A. J.

    1983-01-01

    A computational simulation, based on Mariner 9 data, was performed for the thermal characteristics of the Martian atmospheric surface boundary layer in clear and dust-filled conditions. A radiative transfer model consisting of the atmospheric enthalpy rate equation, the radiative flux integrated over the 0.2-50 microns, the solid angle interval, and 0.50 km altitudes, broken into 52 levels. Mariner 9 IR data for CO2 absorption lines were included in the form of a temperture-dependent equation, while the line-widths were interpreted in terms of the pressure dependene as well as temperature. The lines covered the regions from 1-50 microns and varying conditions of dust content in the atmosphere. Attention was given to the thermal coupling between the ground and the atmosphere. It was found that convective heat exchange develops quickly due to radiative heating of the Martian desert surface, but does not cool the surface because of the attenuated atmosphere. The model predictd the 100 K temperature variations in the dusty atmosphere, as observed by the Viking thermal mapper. It is suggested that radiative flux convergence is as important as convection at equivalent efficiencies.

  1. 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. PMID:27236419

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

  10. Inferences over the sources and processes affecting polycyclic aromatic hydrocarbons in the atmosphere derived from measured data.

    PubMed

    Mari, Montse; Harrison, Roy M; Schuhmacher, Marta; Domingo, José L; Pongpiachan, Siwatt

    2010-05-01

    Data concerning atmospheric lifetime and relative source contributions of polycyclic aromatic hydrocarbons (PAH) are fragmentary and contradictory. In this study, two datasets of measurements of atmospheric PAH (sum of particulate and gaseous phases), one from a national network, the other from a more local three-site study, were analysed and used to infer processes affecting PAH in the atmosphere, and their sources. PAH congener profiles measured at urban and rural locations were remarkably similar suggesting that atmospheric decay processes are relatively slow. This allows the use of such profiles to elucidate sources. A spatial analysis of two PAH datasets showed a clear influence of industry and road traffic upon local PAH concentrations. When Principal Component Analysis (PCA) was applied to UK national network data, it showed a clear influence of steel industry emissions and of home heating emissions from coal and oil in Northern Ireland. These sites also showed different winter/summer concentration ratios to the main group of sites. In the data from Birmingham (UK), PCA identified separate factors relating to gasoline and diesel vehicles, as well as the influence of wood combustion on "Bonfire night", and a factor related to home heating emissions which shows up only in the cold season. PMID:20207394

  11. Toward the influence of clouds on the shortwave radiation budget of the earth-atmosphere system estimated from satellite data

    SciTech Connect

    Rieland, M. ); Stuhlmann, R. )

    1993-05-01

    The purpose of this paper is to investigate the influence of cloudiness on the shortwave radiation budget at the top of the atmosphere, at the surface, and, as a residual, for the atmosphere itself. The data used for this study are derived exclusively from satellite measurements. Calculations for the top of the atmosphere are based entirely on measurements of the Earth Radiation Budget Experiment (ERBE). For the solar radiation budget at the surface, the incoming surface solar radiation is derived from Meteosat data and the surface albedo is calculated from ERBE clear-sky planetary albedo measurements by applying an atmospheric correction scheme. As a result, maps of absorbed solar radiation for the total earth-atmosphere system, the surface, and for the atmosphere are presented for the area of investigation, [+-]60[degrees] longitude and latitude. To infer the contribution of clouds, the concept of cloud radiative forcing is applied to these different datasets. It is shown that the solar cloud forcing at the top of the atmosphere (CF[sub TOA]), and at the surface (CF[sub SUR]), are of the same order of magnitude and well correlated with cloud cover (R = 0.83). On the contrary, the solar cloud forcing of the atmosphere itself, CF[sub ATM], is about one order of magnitude less and not very highly correlated with cloud cover (R = 0.37). The mean value of the annual averaged solar cloud forcing for the area of investigation is calculated for the top of the atmosphere to be CF[sub TOA] = 50 [+-] 4 W m[sup [minus]2], for the surface to be CF[sub SUR] = 55 [+-] 6 W m[sup [minus]2], and for the atmosphere to be CF[sub ATM] = [minus]5 [+-] 10 W m[sup [minus]2]. Related to the annual mean solar insolation, the CF[sub ATM] corresponds to an additional contribution of the clouds to atmospheric solar absorption of 1.4%. The uncertainty range for this additional absorption is calculated to be [minus]1.4% to +4.2%. 41 refs., 16 figs., 3 tabs.

  12. The Use of Iteration Factors Method in the Solution of Multilevel Radiative Transfer Problems in Stellar Atmospheres

    NASA Astrophysics Data System (ADS)

    Kuzmanovska-Barandovska, O.

    2012-12-01

    equation results in a tridiagonal system that is solved, together with the boundary conditions, by a standard Gaussian elimination procedure. In order to test the convergence properties and accuracy of the suggested procedures we solved a standard benchmark problem of spectral line formation by three-level hydrogen atom in plan-parallel isothermal atmosphere with no background continuum and compared its solutions with those obtained by other methods that solved the same test problem. Additionally we solved the problem of spectral line formation by CaII ions with five levels. We also compared the speed of convergence and the total computational time of our method with those of some other methods in use. Finally, we formulated and analyzed a more general line transfer problem in variably property atmosphere with background continuum. For its solution we defined four additional families of iteration factors and tested the convergence properties of the procedures that use them on a solution of linear radiative transfer problem for constant and for variable (with optical depth) absorption profile, as well as on multilevel case. In the conclusion we emphasized that the use of the iteration factors defined in the thesis results in extremely fast convergence to the exact solutions of the problem, with no need of extra mathematical acceleration, necessary for other methods. Also, the use of iteration factors defined for the spectral line as a whole drastically reduces the memory cost and the computational time. The accuracy of the method increases with the number of the grid points, but the very high convergence speed is not affected by the refinement of the grid resolution. So the total computational work scales linearly with the number of the grid points and is couple of times less than needed by other existing methods.

  13. 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

  14. Aerosols in the Convective Boundary Layer: Radiation Effects on the Coupled Land-Atmosphere System

    NASA Astrophysics Data System (ADS)

    Barbaro, E.; Vila-Guerau Arellano, J.; Ouwersloot, H. G.; Schroter, J.; Donovan, D. P.; Krol, M. C.

    2013-12-01

    We investigate the responses of the surface energy budget and the convective boundary-layer (CBL) dynamics to the presence of aerosols using a combination of observations and numerical simulations. A detailed observational dataset containing (thermo)dynamic variables observed at CESAR (Cabauw Experimental Site for Atmospheric Research) and aerosol information from the European Integrated Project on Aerosol, Cloud, Climate, and Air Quality Interactions (IMPACT/EUCAARI) campaign is employed to design numerical experiments reproducing two prototype clear-sky days characterized by: (i) a well-mixed residual layer above a ground inversion and (ii) a continuously growing CBL. A large-eddy simulation (LES) model and a mixed-layer (MXL) model, both coupled to a broadband radiative transfer code and a land-surface model, are used to study the impacts of aerosol scattering and absorption of shortwave radiation on the land-atmosphere system. We successfully validate our model results using the measurements of (thermo)dynamic variables and aerosol properties for the two different CBL prototypes studied here. Our findings indicate that in order to reproduce the observed surface energy budget and CBL dynamics, information of the vertical structure and temporal evolution of the aerosols is necessary. Given the good agreement between the LES and the MXL model results, we use the MXL model to explore the aerosol effect on the land-atmosphere system for a wide range of optical depths and single scattering albedos. Our results show that higher loads of aerosols decrease irradiance, imposing an energy restriction at the surface. Over the studied well-watered grassland, aerosols reduce the sensible heat flux more than the latent heat flux. As a result, aerosols increase the evaporative fraction. Moreover, aerosols also delay the CBL morning onset and anticipate its afternoon collapse. If also present above the CBL during the morning transition, aerosols maintain a persistent near

  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. Adjoint Sensitivity Analysis of Radiative Transfer Equation: Temperature and Gas Mixing Ratio Weighting Functions for Remote Sensing of Scattering Atmospheres in Thermal IR

    NASA Technical Reports Server (NTRS)

    Ustinov, E.

    1999-01-01

    Sensitivity analysis based on using of the adjoint equation of radiative transfer is applied to the case of atmospheric remote sensing in the thermal spectral region with non-negligeable atmospheric scattering.

  17. 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.

  18. The Department of Energy's Atmospheric Radiation Measurement (ARM) Unmanned Aerospace Vehicle (UAV) Program.

    NASA Astrophysics Data System (ADS)

    Stephens, G. L.; Ellingson, R. G.; Vitko, J., Jr.; Bolton, W.; Tooman, T. P.; Valero, F. P. J.; Minnis, P.; Pilewskie, P.; Phipps, G. S.; Sekelsky, S.; Carswell, J. R.; Miller, S. D.; Benedetti, A.; McCoy, R. B.; McCoy, R. F., Jr.; Lederbuhr, A.; Bambha, R.

    2000-12-01

    The U.S. Department of Energy has established an unmanned aerospace vehicle (UAV) measurement program. The purpose of this paper is to describe the evolution of the program since its inception, review the progress of the program, summarize the measurement capabilities developed under the program, illustrate key results from the various UAV campaigns carried out to date, and provide a sense of the future direction of the program. The Atmospheric Radiation Measurement (ARM)-UAV program has demonstrated how measurements from unmanned aircraft platforms operating under the various constraints imposed by different science experiments can contribute to our understanding of cloud and radiative processes. The program was first introduced in 1991 and has evolved in the form of four phases of activity each culminating in one or more flight campaigns. A total of 8 flight campaigns produced over 140 h of science flights using three different UAV platforms. The UAV platforms and their capabilities are described as are the various phases of the program development. Examples of data collected from various campaigns highlight the powerful nature of the observing system developed under the auspices of the ARM-UAV program and confirm the viability of the UAV platform for the kinds of research of interest to ARM and the clouds and radiation community as a whole. The specific examples include applications of the data in the study of radiative transfer through clouds, the evaluation of cloud parameterizations, and the development and evaluation of cloud remote sensing methods. A number of notable and novel achievements of the program are also highlighted.

  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. Radiative Transfer Methods: new exact results for testing the accuracy of the ALI numerical method for a stellar atmosphere

    NASA Astrophysics Data System (ADS)

    Chevallier, L.

    2010-11-01

    Tests are presented of the 1D Accelerated Lambda Iteration method, which is widely used for solving the radiative transfer equation for a stellar atmosphere. We use our ARTY code as a reference solution and tables for these tests are provided. We model a static idealized stellar atmosphere, which is illuminated on its inner face and where internal sources are distributed with weak or strong gradients. This is an extension of published tests for a slab without incident radiation and gradients. Typical physical conditions for the continuum radiation and spectral lines are used, as well as typical values for the numerical parameters in order to reach a 1% accuracy. It is shown that the method is able to reach such an accuracy for most cases but the spatial discretization has to be refined for strong gradients and spectral lines, beyond the scope of realistic stellar atmospheres models. Discussion is provided on faster methods.

  1. Validation of Atmospheric Correction of Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) Radiance Data Based on Radiative Transfer Modeling

    NASA Technical Reports Server (NTRS)

    Carrare, V.; Conel, J. E.

    1993-01-01

    An evaluation of atmospheric correction of AVIRIS data using radiative transfer codes LOWTRAN7 and MODTRAN is presented. The algorithm employed is based on a simple model of radiance L at each wavelength at the sensor that can be written approximately LAV=Lp+Tp, where subscript AV referes to AVIRIS, Lp is the path radiance and Tp is the diffuse + direct transmitted radiance of the atmosphere at AVIRIS.

  2. 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.

  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 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  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. 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.

  17. Stochastic simulation of inner radiation belt electron decay by atmospheric scattering

    NASA Astrophysics Data System (ADS)

    Selesnick, R. S.

    2016-02-01

    Decay of inner radiation belt electron intensity, resulting from elastic and inelastic collisions with neutral atoms, ions, and free electrons of the upper atmosphere, ionosphere, and plasmasphere, is described by stochastic Monte Carlo simulation. Modified collision cross sections allow detailed simulation of large-angle scattering and large-energy-loss collisions while preserving mean effective scattering and slowing-down rates resulting from all collisions. Scattering from bound electrons and δ-ray production are also included. Results show that traditional methods describing diffusion of the mirror point magnetic field, equivalent to diffusion in equatorial pitch angle, and energy loss by continuous slowing down are generally good approximations. Updated formulae for these approximations are provided. The drift-averaging approximation is also shown to provide a generally accurate description of trapped electron decay. The approximate methods overestimate decay rates by small factors, and the detailed stochastic simulation should be used when greater accuracy is required.

  18. A preliminary ocean ARM (Atmospheric Radiation Measurements) guide for climatic evaluations

    SciTech Connect

    Brown, R.M.

    1990-07-01

    This guide was made to assist in the task of selecting sites for the Atmospheric Radiation Measurements (ARM) study. It is a preliminary attempt to provide mean annual and seasonal meteorological data that might be useful in initial climatic evaluations. It is not a finished product and will be added to in time to give other important information on parameters such as standard deviations, % of means and times, and other variances. In order to cover the spectrum of climatic factors to be considered, this generalized climatic guide was established from various publications to provide a diversified set of basic meteorological data that exists. To comply with other site selection restrictions, namely, synergism with other programs and scientific and logistical viability, this guide covers only the United States, except for the material at the end on Koppens World Climate Classification. It is anticipated that a similar guide will be made to cover the world's climate at a later date. 3 refs., 63 figs.

  19. 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.

  20. 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.

  1. Electron conic distributions produced by solar ionizing radiation in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Peterson, W. K.; Brain, D. L.; Yau, A. W.; Richards, P. G.

    2015-06-01

    Electron conic distributions have angular distributions with peak fluxes well separated from the field aligned-direction. They have previously been reported at Earth on auroral field lines and at the Moon and Mars on closed crustal magnetic field lines. Here we report observations of electron conics at Earth on closed magnetic field lines well removed from the aurora. We show how these distributions could be produced without plasma wave interactions when magnetic field lines are illuminated by solar ionizing radiation at relatively high altitudes in the ionosphere. Examination of previous reports of electron conic distributions observed in planetary atmospheres show that there are a variety of physical mechanisms that can lead to their formation, not all of which require wave-particle interactions.

  2. On the generation of atmospheric property Jacobians from the (V)LIDORT linearized radiative transfer models

    NASA Astrophysics Data System (ADS)

    Spurr, Robert; Christi, Matt

    2014-07-01

    The linearized radiative transfer models VLIDORT and LIDORT will deliver profile weighting functions (Jacobians) with respect to layer optical properties. We derive transformation rules for the conversion of layer Jacobian output to weighting functions defined for level (layer boundary) quantities such as volume mixing ratio, temperature and pressure. In a related development, we discuss the derivation of bulk-property atmospheric Jacobians with respect to quantities such as the temperature shift, the surface pressure and scaling parameters for constituent profiles. We also present some rules for calculating Jacobians for parameters characterizing aerosol loading regimes. An appendix contains linearization (with respect to temperature and pressure) of the trace species cross-sections derived from the HITRAN line spectroscopy data base.

  3. 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

  4. 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)

  5. Seasonal meridional energy balance and thermal structure of the atmosphere of Uranus - A radiative-convective-dynamical model

    NASA Technical Reports Server (NTRS)

    Friedson, James; Ingersoll, Andrew P.

    1987-01-01

    A model is presented for the thermodynamics of the seasonal meridional energy balance and thermal structure of the Uranian atmosphere. The model considers radiation and small-scale convection, and dynamical heat fluxes due to large-scale baroclinic eddies. Phase oscillations with a period of 0.5 Uranian year are discerned in the total internal power and global enthalpy storage. The variations in the identity of the main transport agent with the magnitude of the internal heat source are discussed. It is shown that meridional heat transport in the atmosphere is sufficient to lower seasonal horizontal temperature contrasts below those predicted with radiative-convection models.

  6. Atmospheric turbidity and transmittance of solar radiation in Riyadh, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    El-Shobokshy, Mohammad S.; Al-Saedi, Yaseen G.

    During the last two decades, the urban areas in the city of Riyadh—the capital of Saudi Arabia—were increasing at an exceptionally high rate through a series of development plans. The major plans had been completed by the end of 1982. Some other big utility projects were started and completed during 1987. As a consequence, the air quality has deteriorated markedly and air pollution episodes recorded during these activities showed that particulates were present in the atmosphere at high concentrations. Later in January 1991 the Gulf war started and the firing of the oil fields in Kuwait soon followed. It was estimated that soot particulates were emitted at a rate of 600 ton d -1 along with high rates of other gases. This event has led to significant air quality and visibility problems. Direct normal solar radiation has been measured during the summer months of July and August which were characterized by very dry and cloudless weather for the period between 1982 and 1992. A year-to-year trend of the transmittance of direct normal solar irradiance was then determined. The atmospheric fine aerosol (<2 μm diameter) loading data during the same period were used to establish a correlation between the aerosol concentration and the extinction coefficient. The total horizontal and direct normal solar radiation measurements during some days when the dark smoke emitted from the oil field fires in Kuwait were passing over Riyadh are presented. The reduction in solar irradiation reflects the intensity of dark smoke at a distance of 500 km from Kuwait.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.}

  13. Potential Aerosol Indirect Effects on Atmospheric Circulation and Radiative Forcing through Deep Convection

    SciTech Connect

    Fan, Jiwen; Rosenfeld, Daniel; Ding, Yanni; Leung, Lai-Yung R.; Li, Zhanqing

    2012-05-10

    Aerosol indirect effects, i.e., the interactions of aerosols with clouds by serving as cloud condensation nuclei (CCN) or ice nuclei (IN), constitute the largest uncertainty in climate forcing and projection. Previous IPCC reported aerosol indirect forcing is negative, which does not account for aerosol-convective cloud interactions because the complex processes involved are poorly understood and represented in climate models. Here we report that aerosol indirect effect on deep convective cloud systems can lead to enhanced regional convergence and a strong top-of atmosphere (TOA) warming. Aerosol invigoration effect on convection can result in a strong radiative warming in the atmosphere (+5.6 W m-2) due to strong night-time warming, a lofted latent heating, and a reduced diurnal temperature difference, all of which could remarkably impact regional circulation and modify weather systems. We further elucidated how aerosols change convective intensity, diabatic heating, and regional circulation under different environmental conditions and concluded that wind shear and cloud base temperature play key roles in determining the significance of aerosol invigoration effect for convective systems.

  14. The Relationship of Cancer Symptom Clusters to Depressive Affect in the Initial Phase of Palliative Radiation

    PubMed Central

    Francoeur, Richard Benoit

    2007-01-01

    Research on comorbidity across cancer symptoms, including pain, fatigue, and depression, could suggest if crossover effects from symptom-specific interventions are plausible. Secondary analyses were conducted on a survey of 268 cancer patients with recurrent disease from a northeastern U.S. city who were initiating palliative radiation for bone pain. Moderator regression analyses predicted variation in depressive affect that could be attributed to symptom clusters. Patients self-reported difficulty controlling each physical symptom over the past month on a Likert scale and depressive symptoms on a validated depression measure (Center for Epidemiologic Studies-Depression [CES-D]) over the past week on a four-category scale. An index of depressive affect was based on items of negative and positive affect from the CES-D. In predicting depressive affect, synergistic interactions of pain with fever, fatigue, and weight loss suggest separate pathways involving pain. A similar interaction with fever occurs when nausea was tested in place of pain. Further, the interaction between pain and fatigue is similar in form to the interaction between difficulty breathing and fatigue (when sleep is not a problem). Follow-up to the latter interaction reveals: 1) additional moderation by hypertension and palliative radiation to the hip/pelvis; and 2) a similar cluster not involving hypertension when appetite problems and weight loss were tested in place of fatigue. The significance and form of these interactions are remarkably consistent. Similar sickness mechanisms could be generating: 1) pain and nausea during fever; 2) pain and fatigue during weight loss; and 3) pain and breathing difficulty when fatigue is pronounced. Crossover effects from symptom-specific interventions appear promising. PMID:15733806

  15. An Energetic Perspective on Aerosol Radiative Forcing and Interactions with Atmospheric Wave Activity

    NASA Astrophysics Data System (ADS)

    Hosseinpour, F.; Wilcox, E. M.; Colarco, P. R.

    2014-12-01

    Aerosols have the capability to alter regional-scale atmospheric circulations. A better understanding of the contribution of aerosols to multi-scale atmospheric phenomena and their transient changes is crucial for efforts to evaluate climate predictions using next generation climate models. In this study we address the following questions: (1) Is there a mechanistic relationship between variability of oceanic dust aerosol forcing and transient changes in the African easterly jet- African easterly wave (AEJ-AEW) system? (2) What are the long-term impacts of possible aerosol-wave interactions on climate dynamics of eastern tropical Atlantic Ocean and western African monsoon (WAM) region during boreal summer seasons? Our hypothesis is that aerosol radiative forcing may act as additional energy source to fuel the development of African easterly waves on the northern and southern sides of the AEJ. Evidence in support of this hypothesis is presented based on analysis of an ensemble of NASA satellite data sets, including aerosol optical thickness (AOT) observations from the Moderate Resolution Imaging Spectro-radiometer (MODIS) and the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), as well as an atmospheric reanalysis from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) and a simulation of global aerosol distributions made with the Goddard Earth Observing System Model version 5 (GEOS-5) Earth system model with meteorology constrained by MERRA and an assimilation of MODIS AOT (MERRAero). We propose that the impacts of Saharan aerosols on the regional climate dynamics occur through contributions to the eddy energy of waves with 2—7-day and 7—11-day variability.

  16. 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.

  17. Investigation of aerosol components influencing atmospheric transfer of UV radiation in Baltic Sea region

    NASA Astrophysics Data System (ADS)

    Reinart, A.; Kikas, Ü.; Tamm, E.

    2006-01-01

    Linking of atmospheric aerosol size distributions and optical properties via predefined aerosol components was investigated. The measured aerosol volume distributions were decomposed to Optical Properties of Aerosols and Clouds (OPAC) components, and aerosol optical properties were calculated for a mixture of those components. The obtained aerosol optical properties were then used for modeling the surface UV irradiances with the libRadtran radiative transfer code. The results were verified with the columnar aerosol characteristics obtained from Aerosol Robotic Network (AERONET) station Tõravere (58.26°N, 26.46°E) and clear-sky surface UV measurements in Pärnu, Estonia (58.38°N, 24.51°E). The best decomposition results were obtained with four OPAC components, when their lookup characteristics varied within ±10%. Variation of aerosol optical properties in 17 days was influenced by the following aerosol components: soot, 1.2 ± 1.4%; insoluble, 23.1 ± 8.3%; water-soluble, 44.0 ± 10.8%; accumulation mode sea salt, 31.6 ± 6.2% of total aerosol volume. The average refractive index (for λ = 440 nm) of the component mixture was of 1.42 - 0.013i. Interpretation of the soot component was disputable, since similarly high soot concentrations corresponded to the secondary particles in polluted atmosphere and the nucleation bursts in clean atmosphere. The sea-salt component showed a correlation with the aerosol residence time over sea. The water-soluble component and the additional "biomass haze" component represented partly the same aerosol volume in the diameter range of 0.18-1.8 μm. The surface UV irradiances modeled with the AERONET data and the fitted aerosol components were highly correlated with each other, but both model results underestimated the UV extinction by aerosol.

  18. 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.

  19. Does chronic nitrogen deposition during biomass growth affect atmospheric emissions from biomass burning?

    NASA Astrophysics Data System (ADS)

    Giordano, Michael R.; Chong, Joey; Weise, David R.; Asa-Awuku, Akua A.

    2016-03-01

    Chronic nitrogen deposition has measureable impacts on soil and plant health. We investigate burning emissions from biomass grown in areas of high and low NO x deposition. Gas and aerosol-phase emissions were measured as a function of photochemical aging in an environmental chamber at UC-Riverside. Though aerosol chemical speciation was not available, results indicate a systemic compositional difference between biomass grown in high and low deposition areas. Aerosol emissions from biomass grown in areas of high NO x deposition exhibit a lower volatility than biomass grown in a low deposition area. Furthermore, fuel elemental analysis, NO x emission rates, and aerosol particle number distributions differed significantly between the two sites. Despite the limited scale of fuels explored, there is strong evidence that the atmospheric emissions community must pay attention to the regional air quality of biomass fuels growth areas.

  20. The CHUVA Project Contributions to the Understanding of Anthropogenic Interactions Affecting the Atmospheric Physics over Amazonas.

    NASA Astrophysics Data System (ADS)

    Machado, L.; Cecchini, M. A.; Gonçalves, W.

    2014-12-01

    CHUVA, meaning "rain" in Portuguese, is the acronym for the Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement). The CHUVA project has conducted six field campaigns; the last campaign was held in Manaus in 2014 jointly with GoAmazon and ACRIDICON. CHUVA's main scientific motivation is to contribute to the understanding of cloud processes, which represent one of the least understood components of the weather and climate system. This study will briefly describe the CHUVA project and the main scientific results obtained in the Amazon region. Specifically, we will describe the results of one year radar observation of Manaus rainfall and the relationship with black carbon. The results indicate that the aerosol influence on precipitating systems is modulated by the atmospheric instability degree. For stable atmospheres, the higher the aerosol concentration, the lower the precipitation over the region. On the other hand, for unstable cases, higher concentrations of particulate material are associated with more precipitation, elevated presence of ice and larger rain cells, which suggests an association with long lived systems. Also we will describe some preliminary results obtained during GoAmazon describing the cloud and rainfall size distribution (DSD). The DSD was adjusted to the gamma function using the momentum method and disposed in the three-dimensional space of the gamma parameters: the intercept, the shape and the width. Each point in this three-dimensional space corresponds to a specific DSD and the ensemble of points describes all regimes of precipitation in Amazon. Based in this Gamma space we will discuss the characteristics of the rainfall regime and anthropogenic features.

  1. Responses to iron limitation in Hordeum vulgare L. as affected by the atmospheric CO2 concentration.

    PubMed

    Haase, S; Rothe, A; Kania, A; Wasaki, J; Römheld, V; Engels, C; Kandeler, E; Neumann, G

    2008-01-01

    Elevated atmospheric CO2 treatments stimulated biomass production in Fe-sufficient and Fe-deficient barley plants, both in hydroponics and in soil culture. Root/shoot biomass ratio was increased in severely Fe-deficient plants grown in hydroponics but not under moderate Fe limitation in soil culture. Significantly increased biomass production in high CO2 treatments, even under severe Fe deficiency in hydroponic culture, indicates an improved internal Fe utilization. Iron deficiency-induced secretion of PS in 0.5 to 2.5 cm sub-apical root zones was increased by 74% in response to elevated CO2 treatments of barley plants in hydroponics but no PS were detectable in root exudates collected from soil-grown plants. This may be attributed to suppression of PS release by internal Fe concentrations above the critical level for Fe deficiency, determined at final harvest for soil-grown barley plants, even without additional Fe supply. However, extremely low concentrations of easily plant-available Fe in the investigated soil and low Fe seed reserves suggest a contribution of PS-mediated Fe mobilization from sparingly soluble Fe sources to Fe acquisition of the soil-grown barley plants during the preceding culture period. Higher Fe contents in shoots (+52%) of plants grown in soil culture without Fe supply under elevated atmospheric CO2 concentrations may indicate an increased efficiency for Fe acquisition. No significant influence on diversity and function of rhizosphere-bacterial communities was detectable in the outer rhizosphere soil (0-3 mm distance from the root surface) by DGGE of 16S rRNA gene fragments and analysis of marker enzyme activities for C-, N-, and P-cycles. PMID:18453445

  2. X-ray radiation from the volume discharge in atmospheric-pressure air

    NASA Astrophysics Data System (ADS)

    Bratchikov, V. B.; Gagarinov, K. A.; Kostyrya, I. D.; Tarasenko, V. F.; Tkachev, A. N.; Yakovlenko, S. I.

    2007-07-01

    X-ray radiation from the volume discharge in atmospheric-pressure air is studied under the conditions when the voltage pulse rise time varies from 0.5 to 100 ns and the open-circuit voltage amplitude of the generator varies from 20 to 750 kV. It is shown that a volume discharge from a needle-like cathode forms at a relatively wide voltage pulse (to ≈60 ns in this work). The volume character of the discharge is due to preionization by fast electrons, which arise when the electric field concentrates at the cathode and in the discharge gap. As the voltage pulse rise time grows, X-ray radiation comes largely from the discharge gap in accordance with previous experiments. Propagation of fast avalanche electrons in nitrogen subjected to a nonuniform unsteady electric field is simulated. It is demonstrated that the amount of hard X-ray photons grows not only with increasing voltage amplitude but also with shortening pulse rise time.

  3. Plasma radiation for atmospheric entry at Titan: Emission spectroscopy measurements and numerical rebuilding

    NASA Astrophysics Data System (ADS)

    Sobbia, R.; Leyland, P.; Babou, Y.; Potter, D.; Marraffa, L.; Marraffa

    2013-10-01

    Emission spectroscopy measurements on a plasma representative of Titan atmosphere composition were obtained in the Inductively Coupled Plasma wind tunnel facility (VKI-Minitorch) at the von Karman Institute in Belgium. Temperatures ranged from 3600 to 5000 K, pressure was fixed at 300 mbar, and the molar composition was 1.9% CH4 and 98.1% N2. The high-pressure plasma was produced to obtain conditions close to equilibrium. In conjunction, line-by-line calculations have been carried out to assess the reliability of two distinct sets of molecular electronic transition moments, recently released, by predicting the radiative signature of high-temperature N2-CH4 plasma. The radiative transfer problem was solved by considering the plasma plume at local thermodynamic equilibrium conditions in an axisymmetric configuration. Comparisons between the synthetic and experimental spectra demonstrated good agreement for the CN Violet and high-wavelength CN Red bands, while some discrepancies were observed for the C2 Swan bands and low-wavelength CN Red bands.

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    Subvisible cirrus clouds (SCi) were easily distinguished in mid-infrared (MIR) TIROS-N daytime data from south Texas and northeast Mexico. The MIR (3.55-3.93 micrometer) pixel digital count means of the SCi affected areas were more than 3.5 standard deviations on the cold side of the scene means. (These standard deviations were made free of the effects of unusual instrument error by factoring out the Ch 3 MIR noise on the basis of detailed examination of noisy and noise-free pixels). SCi affected areas in the IR Ch 4 (10.5-11.5 micrometer) appeared cooler than the general scene, but were not as prominent as in Ch 3, being less than 2 standard deviations from the scene mean. Ch 3 and 4 standard deviations and coefficients of variation are not reliable indicators, by themselves, of the presence of SCi because land features can have similar statistical properties.

  5. 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.; Goodier, B. G.

    1981-01-01

    The location and migration of cloud, land and water features were examined in spectral space (reflective VIS vs. emissive IR). Daytime HCMM data showed two distinct types of cloud affected pixels in the south Texas test area. High altitude cirrus and/or cirrostratus and "subvisible cirrus" (SCi) reflected the same or only slightly more than land features. In the emissive band, the digital counts ranged from 1 to over 75 and overlapped land features. Pixels consisting of cumulus clouds, or of mixed cumulus and landscape, clustered in a different area of spectral space than the high altitude cloud pixels. Cumulus affected pixels were more reflective than land and water pixels. In August the high altitude clouds and SCi were more emissive than similar clouds were in July. Four-channel TIROS-N data were examined with the objective of developing a multispectral screening technique for removing SCi contaminated data.

  6. 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.

  7. A simple 1-D radiative-convective atmospheric model designed for integration into coupled models of magma ocean planets

    NASA Astrophysics Data System (ADS)

    Marcq, E.

    2012-01-01

    In order to understand the early history of telluric interiors and atmospheres during the ocean magma stage, a coupled interior-atmosphere-escape model is being developed. This paper describes the atmospheric part and its first preliminary results. A unidimensional, radiative-convective, H2O-CO2 atmosphere is modeled following a vertical T(z) profile similar to Kasting (1988) and Abe and Matsui (1988). Opacities in the thermal IR are then computed using a k-correlated code (KSPECTRUM), tabulated continuum opacities for H2O-H2O and CO2-CO2 absorption, and water or sulphuric acid clouds in the moist convective zone (whenever present). The first results show the existence of two regimes depending on the relative value of the surface temperature Ts compared to a threshold temperature Tc depending on the total gaseous inventory. For Ts