WorldWideScience

Sample records for atmospheric radiation measurement

  1. Atmospheric Radiation Measurement Program plan

    International Nuclear Information System (INIS)

    In order to understand energy's role in anthropogenic global climate change, significant reliance is being placed on General Circulation Models (GCMs). A major goal is to foster the development of GCMs capable of predicting the timing and magnitude of greenhouse gas-induced global warming and the regional effects of such warming. The Atmospheric Radiation Measurement (ARM) Program will contribute to the Department of Energy goal by improving the treatment of cloud radiative forcing and feedbacks in GCMs. Two issues will be addressed: the radiation budget and its spectral dependence and the radiative and other properties of clouds. The experimental objective of the ARM Program is to characterize empirically the radiative processes in the Earth's atmosphere with improved resolution and accuracy. A key to this characterization is the effective treatment of cloud formation and cloud properties in GCMs. Through this characterization of radiative properties, it will be possible to understand both the forcing and feedback effects. 19 refs., 4 figs., 2 tabs

  2. Atmospheric Radiation Measurement Program Plan

    International Nuclear Information System (INIS)

    In order to understand energy's role in anthropogenic global climate change, significant reliance is being placed on General Circulation Models (GCMs). A major goal of the Department is to foster the development of GCMs capable of predicting the timing and magnitude of greenhouse gas-induced global warming and the regional effects of such warming. DOE research has revealed that cloud radiative feedback is the single most important effect determining the magnitude of possible climate responses to human activity. However, cloud radiative forcing and feedbacks are not understood at the levels needed for reliable climate prediction. The Atmospheric Radiation Measurement (ARM) Program will contribute to the DOE goal by improving the treatment of cloud radiative forcing and feedbacks in GCMs. Two issues will be addressed: the radiation budget and its spectral dependence and the radiative and other properties of clouds. Understanding cloud properties and how to predict them is critical because cloud properties may very well change as climate changes. The experimental objective of the ARM Program is to characterize empirically the radiative processes in the Earth's atmosphere with improved resolution and accuracy. A key to this characterization is the effective treatment of cloud formation and cloud properties in GCMs. Through this characterization of radiative properties, it will be possible to understand both the forcing and feedback effects. GCM modelers will then be able to better identify the best approaches to improved parameterizations of radiative transfer effects. This is expected to greatly improve the accuracy of long-term, GCM predictions and the efficacy of those predictions at the important regional scale, as the research community and DOE attempt to understand the effects of greenhouse gas emissions on the Earth's climate. 153 refs., 24 figs., 6 tabs

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shi, L.; Bernstein, R.L. [SeaSpace Corp., San Diego, CA (United States)

    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.

  5. Atmospheric radiation measurement program facilities newsletter, June 2002.; TOPICAL

    International Nuclear Information System (INIS)

    ARM Intensive Operational Period Scheduled to Validate New NASA Satellite-Beginning in July, all three ARM sites (Southern Great Plains[SGP], North Slope of Alaska, and Tropical Western Pacific; Figure 1) will participate in the AIRS Validation IOP. This three-month intensive operational period (IOP) will validate data collected by the satellite-based Atmospheric Infrared Sounder (AIRS) recently launched into space. On May 4, the National Aeronautics and Space Administration (NASA) launched Aqua, the second spacecraft in the Earth Observing System (EOS) series. The EOS satellites monitor Earth systems including land surfaces, oceans, the atmosphere, and ice cover. The first EOS satellite, named Terra, was launched in December 1999. The second EOS satellite is named Aqua because its primary focus is understanding Earth's water cycle through observation of atmospheric moisture, clouds, temperature, ocean surface, precipitation, and soil moisture. One of the instruments aboard Aqua is the AIRS, built by the Jet Propulsion Laboratory, a NASA agency. The AIRS Validation IOP complements the ARM mission to improve understanding of the interactions of clouds and atmospheric moisture with solar radiation and their influence on weather and climate. In support of satellite validation IOP, ARM will launch dedicated radiosondes at all three ARM sites while the Aqua satellite with the AIRS instrument is orbiting overhead. These radiosonde launches will occur 45 minutes and 5 minutes before selected satellite overpasses. In addition, visiting scientists from the Jet Propulsion Laboratory will launch special radiosondes to measure ozone and humidity over the SGP site. All launches will generate ground-truth data to validate satellite data collected simultaneously. Data gathered daily by ARM meteorological and solar radiation instruments will complete the validation data sets. Data from Aqua-based instruments, including AIRS, will aid in weather forecasting, climate modeling, and

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    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.

  8. Atmospheric thermal radiation from historical measurements to investigations of the Earth's greenhouse effect

    OpenAIRE

    Rolf Philipona

    2013-01-01

    Here, we recall first quantitative measurements of terrestrial and atmospheric thermal infrared radiation that were made about hundred years ago, and relate them to present day radiation budget measurements and greenhouse effect investigations through the atmosphere. At the beginning of the 20th century measurements of the effective terrestrial radiation and the counter-radiation of the atmosphere were of great interest primarily to prove theoretical aspects of the Earth radiation balance...

  9. Atmospheric radiation measurement program facilities newsletter, September 2001.; TOPICAL

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Atmospheric Radiation Measurement Program facilities newsletter, July 2001.; TOPICAL

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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

  15. The possible direct use of satellite radiance measurements by the Atmospheric Radiation Measurement Program

    International Nuclear Information System (INIS)

    The Atmospheric Radiation Measurement (ARM) Program is a major research program initiated by the Department of Energy to improve our understanding of radiative and cloud processes critical to predicting the Earth's climate and its changes. Central to this concept is the use of four to six intensively instrumented sites for long-term study and characterization of the processes of interest. The instrumentation suites will include ground-based, high-accuracy radiometers for measuring the short and longwave surface flux, as well as an extensive set of ground-and air-based instrumentation for characterizing the intervening atmospheric column. Satellite-based measurements are expected to play a very important role in providing top-of-the-atmosphere measurements. In this study, we examine the possibility of comparing ARM outputs directly with satellite measurements, thereby ensuring the independence of these two important data sets. Thus we focused on what do satellites really measure and how well do they measure it. On what can we do about the general lack of adequate visible channel calibration. On what is the best way for ARM to obtain near-real-time access to this unprocessed data. And on what is the optimum way for ARM to make use of satellite data

  16. Atmospheric Radiation Measurement program facilities newsletter, April 2002.; TOPICAL

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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 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).

  18. Analysis of the effects of aerosol distribution in the atmosphere on surface radiative measurements

    International Nuclear Information System (INIS)

    The distribution of atmospheric aerosols in the atmosphere may have important effects on the radiative properties of the atmosphere and thereby on the climate. The Atmospheric and Geophysical Sciences Division of the Lawrence Livermore National Laboratory is working with the Atmospheric Radiation Measurements (ARM) program to advise the program as to the importance of aerosols to the ARM measurement plan. The ARM Program had established a set of goals which highlight the important areas of scientific needs associated with the understanding and prediction of global climate change. This report summarizes the initial studies performed to assess the importance and effects of atmospheric aerosols on the measurements of atmospheric radiation. To accomplish this, three interlinked models were employed which calculated the MIE parameters, averaged over the appropriate size distributions and computed the solar radiation at the surface. These models are discussed. A number of computations were performed using different aerosol scenarios and size distributions. These results are discussed and a summary of these initial calculations and future directions of research are outlined

  19. Atmospheric Radiation Measurement Program facilities newsletter, February 2001.; TOPICAL

    International Nuclear Information System (INIS)

    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 with

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

    Science.gov (United States)

    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.

  1. Atmospheric Radiation Measurement Climate Research Facility Annual Report 2006

    Energy Technology Data Exchange (ETDEWEB)

    LR Roeder

    2005-11-30

    This annual report describes the purpose and structure of the ARM Climate Research Facility and ARM Science programs and presents key accomplishments in 2006. Noteworthy scientific and infrastructure accomplishments in 2006 include: • Collaborating with the Australian Bureau of Meteorology to lead the Tropical Warm Pool-International Cloud Experiment, a major international field campaign held in Darwin, Australia • Successfully deploying the ARM Mobile Facility in Niger, Africa • Developing the new ARM Aerial Vehicles Program (AVP) to provide airborne measurements • Publishing a new finding on the impacts of aerosols on surface energy budget in polar latitudes • Mitigating a long-standing double-Intertropical Convergence Zone problem in climate models using ARM data and a new cumulus parameterization scheme.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    JW Voyles

    2008-01-30

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

  5. Atmospheric radiation measurement program facilities newsletter, August 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Holdridge, D. J.,ed.

    2001-09-04

    Summer 2001 Heat Wave--This summer has proved to be downright hot in the Southern Great Plains states. The temperatures soared to record-setting levels. The state of Oklahoma saw its fourth hottest July since 1895, while Kansas experienced its seventh warmest. The average temperature throughout most of Oklahoma for the month of July was 2.5-5.5 F above normal. The highest temperature recorded in the region during July was 107 F in Oklahoma City. Wichita, Kansas, had 17 July days with recorded temperatures of 100 F or above, while Medicine Lodge, Kansas, had 21. In addition, Oklahoma suffered its ninth driest July, with precipitation levels much below normal. Kansas fared better, receiving above-normal precipitation amounts. Nevertheless, regional July rainfall averaged 1.5-3.0 inches below normal. Not only is a summer heat wave uncomfortable, but it can also be dangerous. The National Weather Service (NWS) has increased efforts to alert the public to the hazards of heat waves. Prolonged excessive heat and humidity stress the human body and can, in some cases, cause death. The NWS has devised a heat index that is a measure of the heat we perceive as a function of air temperature and humidity. A heat index chart displays different zones from caution to extreme danger, much like a wind chill index chart used in the winter. The values represent conditions of light winds and shade. Thus, in full sunshine heat index values can increase by 15 F. Exposure to winds in hot, dry weather can be equally dangerous. The NWS sends out alerts when the heat index is expected to reach values with significant potential impact. The danger of heat-related illness increases with the number of consecutive days with high heat and humidity levels. Heat and humidity take their toll faster on the elderly, small children, and those with respiratory health problems. Heat-related illnesses come in several forms with different symptoms. From common sunburns to heat stroke, these heat disorders

  6. Atmospheric radiation measurement program facilities newsletter, August 2001.; TOPICAL

    International Nuclear Information System (INIS)

    Summer 2001 Heat Wave-This summer has proved to be downright hot in the Southern Great Plains states. The temperatures soared to record-setting levels. The state of Oklahoma saw its fourth hottest July since 1895, while Kansas experienced its seventh warmest. The average temperature throughout most of Oklahoma for the month of July was 2.5-5.5 F above normal. The highest temperature recorded in the region during July was 107 F in Oklahoma City. Wichita, Kansas, had 17 July days with recorded temperatures of 100 F or above, while Medicine Lodge, Kansas, had 21. In addition, Oklahoma suffered its ninth driest July, with precipitation levels much below normal. Kansas fared better, receiving above-normal precipitation amounts. Nevertheless, regional July rainfall averaged 1.5-3.0 inches below normal. Not only is a summer heat wave uncomfortable, but it can also be dangerous. The National Weather Service (NWS) has increased efforts to alert the public to the hazards of heat waves. Prolonged excessive heat and humidity stress the human body and can, in some cases, cause death. The NWS has devised a heat index that is a measure of the heat we perceive as a function of air temperature and humidity. A heat index chart displays different zones from caution to extreme danger, much like a wind chill index chart used in the winter. The values represent conditions of light winds and shade. Thus, in full sunshine heat index values can increase by 15 F. Exposure to winds in hot, dry weather can be equally dangerous. The NWS sends out alerts when the heat index is expected to reach values with significant potential impact. The danger of heat-related illness increases with the number of consecutive days with high heat and humidity levels. Heat and humidity take their toll faster on the elderly, small children, and those with respiratory health problems. Heat-related illnesses come in several forms with different symptoms. From common sunburns to heat stroke, these heat disorders

  7. Measurement and simulation of the radiation environment in the lower atmosphere for dose assessment

    International Nuclear Information System (INIS)

    Flying personnel is occupationally exposed to rather high radiation levels due to secondary cosmic radiation. Therefore, the radiation environment induced in the lower atmosphere by galactic and solar cosmic radiation was characterized by means of particle transport calculations using GEANT4. These calculations were validated with continuous measurements of the energy spectra of secondary neutrons with Bonner sphere spectrometers at the Zugspitze mountain and near the North Pole. The response of these instruments was determined with GEANT4 and for the first time experimentally verified at high neutron energies (244 and 387 MeV). Route doses for aircrews along typical long-haul flights were determined for galactic and solar cosmic radiation using most recent data on the magnetospheric field and primary cosmic radiation.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Dooraghi, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    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.

  11. Electron density and temperature measurement by continuum radiation emitted from weakly ionized atmospheric pressure plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sanghoo; Choe, Wonho, E-mail: wchoe@kaist.ac.kr [Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Youn Moon, Se [High-enthalpy Plasma Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju 561-756 (Korea, Republic of); Park, Jaeyoung [5771 La Jolla Corona Drive, La Jolla, CA 92037 (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Long, Chuck [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.

    2016-07-01

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

  14. Proceedings of the second Atmospheric Radiation Measurement (ARM) Science Team Meeting

    International Nuclear Information System (INIS)

    The second Atmospheric Radiation Measurement (ARM) Science Team Meeting was held in Denver, Colorado, in October 1991. The five-day meeting provided a forum for a technical exchange among the members of the ARM Science Team and a discussion of the technical aspects of the project infrastructure. The meeting included several activities: Science Team presentations, discussions of the first site occupation plan, experiment design sessions, and poster sessions. This Proceedings document includes papers presented at the meeting. The papers included are those from the technical sessions, the experiment design sessions, the first site occupation, and descriptions of locales for future sites. Individual projects are processed separately for the database

  15. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report July 1–September 30, 2012

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Atmospheric Radiation Measurement Program Science Plan. Current Status and Future Directions of the ARM Science Program

    Energy Technology Data Exchange (ETDEWEB)

    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

  17. Atmospheric Radiative Transfer

    Science.gov (United States)

    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.

  18. INSTRUMENTATION FOR MEASURING AND TRANSMISSION THE SOLAR RADIATION THROUGH EARTH’S ATMOSPHERE

    OpenAIRE

    Alexandru Dan Toma

    2013-01-01

    The Sun's energy is distributed over a broad range of the electromagnetic spectrum and Sun behaves approximately like a "blackbody" radiating at a temperature of about 5800 K with maximum output in the green-yellow part of the visible spectrum, around 500 nm. Not all solar radiation reaching the top of the atmosphere reaches Earth's surface due to a various optical phenomena in regard to solar radiation crossing the Earth’s atmosphere. In order to investigate them, there are two general categ...

  19. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2009

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 - June 30, 2008

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2006

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report July 1–September 30, 2011

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - July 1 - September 30, 2008

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Data management and scientific integration within the Atmospheric Radiation Measurement Program

    Science.gov (United States)

    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

  5. Proceedings of the sixth Atmospheric Radiation Measurement (ARM) Science Team meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    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.

  6. Atmospheric dispersion of argon-41 from anuclear research reactor: measurement and modeling of plume geometry and gamma radiation field

    DEFF Research Database (Denmark)

    Lauritzen, Bent; Astrup, Poul; Drews, Martin;

    2003-01-01

    An atmospheric dispersion experiment was conducted using a visible tracer along with the routine release of argon-41 from the BR1 research reactor in Mol, Belgium. Simultaneous measurements of plume geometry and radiation fields for argon-41 decay were performed as well as measurements of the argon...

  7. Single-column data assimilation for the Atmospheric Radiation Measurement (ARM) Program

    International Nuclear Information System (INIS)

    The main purpose of the ARM program is to provide the necessary data to develop, test and validate the parameterization of clouds and of their interactions with the radiation field, and the computation of radiative transfer in climate models. For various reasons, much of the ARM observations will be imperfect, incomplete, redundant, indirect and unrepresentative. Various techniques of data assimilation have been developed to deal with these problems. The variational data assimilation and adjoint method applied to a single column model is described here. A model is used to simulate the evolution of the atmosphere during an assimilation period. As the model is run, a cost function is computed which is essentially a measure of simulation errors. The method then consists in adjusting some model parameters to minimize the cost function. Optimization of the model parameters needs to be done with a much longer series of data, to cover different meteorological situations. Once parameters are set, nudging terms are used as control variables. The Derber nudging method will require considerable tuning, especially in defining the vertical profiles of the nudging terms. Extensive tests are currently underway of both model optimization and data assimilation

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

    Energy Technology Data Exchange (ETDEWEB)

    Turner, D. D. [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Knuteson, R. O. [Univ. of Wisconsin, Madison, WI (United States); Revercomb, H. E. [Univ. of Wisconsin, Madison, WI (United States); Dedecker, R. G. [Univ. of Wisconsin, Madison, WI (United States); Feltz, W. F. [Univ. of Wisconsin, Madison, WI (United States)

    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.

  9. The Atmospheric radiation measurement (ARM program network of microwave radiometers: instrumentation, data, and retrievals

    Directory of Open Access Journals (Sweden)

    M. P. Cadeddu

    2013-09-01

    Full Text Available The Climate Research Facility of the US Department of Energy's Atmospheric Radiation Measurement (ARM Program operates a network of ground-based microwave radiometers. Data and retrievals from these instruments have been available to the scientific community for almost 20 yr. In the past five years the network has expanded to include a total of 22 microwave radiometers deployed in various locations around the world. The new instruments cover a frequency range between 22 and 197 GHz and are consistently and automatically calibrated. The latest addition to the network is a new generation of three-channel radiometers, currently in the early stage of deployment at all ARM sites. The network has been specifically designed to achieve increased accuracy in the retrieval of precipitable water vapor (PWV and cloud liquid water path (LWP with the long-term goal of providing the scientific community with reliable, calibrated radiometric data and retrievals of important geophysical quantities with well-characterized uncertainties. The radiometers provide high-quality, continuous datasets that can be utilized in a wealth of applications and scientific studies. This paper presents an overview of the microwave instrumentation, calibration procedures, data, and retrievals that are available for download from the ARM data archive.

  10. The Atmospheric Radiation Measurement (ARM program network of microwave radiometers: instrumentation, data, and retrievals

    Directory of Open Access Journals (Sweden)

    M. P. Cadeddu

    2013-04-01

    Full Text Available The Climate Research Facility of the US Department of Energy's Atmospheric Radiation Measurement (ARM Program operates a network of ground-based microwave radiometers. Data and retrievals from these instruments have been available to the scientific community for almost 20 yr. In the past five years the network has been expanded to include a total of 22 microwave radiometers deployed in various locations around the world. The new instruments cover a frequency range between 22 and 197 GHz and are consistently and automatically calibrated. The latest addition to the network is a new generation of three-channel radiometers currently in the early stage of deployment at all ARM sites. The network has been specifically designed to achieve increased accuracy in the retrieval of precipitable water vapor (PWV and cloud liquid water path (LWP with the long-term goal of providing the scientific community with reliable, calibrated radiometric data and retrievals of important geophysical quantities with well-characterized uncertainties. The radiometers provide high-quality, continuous datasets that can be utilized in a wealth of applications and scientific studies. This paper presents an overview of the microwave instrumentation, calibration procedures, data, and retrievals that are available for download from the ARM data archive.

  11. Atmospheric radiation flight dose rates

    Science.gov (United States)

    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.

  12. Different atmospheric parameters influence on spectral UV radiation (measurements and modelling)

    Energy Technology Data Exchange (ETDEWEB)

    Chubarova, N.Y. [Moscow State Univ. (Russian Federation). Meteorological Observatory; Krotkov, N.A. [Maryland Univ., MD (United States). JCESS/Meteorology Dept.; Geogdzhaev, I.V.; Bushnev, S.V.; Kondranin, T.V. [SUMGF/MIPT, Dolgoprudny (Russian Federation); Khattatov, V.U. [Central Aerological Observatory, Dolgoprudny (Russian Federation)

    1995-12-31

    The ultraviolet (UV) radiation plays a vital role in the biophysical processes despite its small portion in the total solar flux. UV radiation is subject to large variations at the Earth surface depending greatly on solar elevation, ozone and cloud amount, aerosols and surface albedo. The analysis of atmospheric parameters influence is based on the spectral archive data of three spectral instruments: NSF spectroradiometer (Barrow network) (NSF Polar Programs UV Spectroradiometer Network 1991-1992,1992), spectrophotometer (SUVS-M) of Central Aerological Observatory CAO, spectroradiometer of Meteorological Observatory of the Moscow State University (MO MSU) and model simulations based on delta-Eddington approximation

  13. Can Top-of-Atmosphere Radiation Measurements Constrain Climate Predictions? Part I: Tuning

    OpenAIRE

    Simon F. B. Tett; Mineter, Michael J.; Cartis, Coralia; Rowlands, Daniel J.; Liu, Ping

    2013-01-01

    Perturbed physics configurations of version 3 of the Hadley Centre Atmosphere Model (HadAM3) driven with observed sea surface temperatures (SST) and sea ice were tuned to outgoing radiation observations using a Gauss-Newton line search optimization algorithm to adjust the model parameters. Four key parameters that previous research found affected climate sensitivity were adjusted to several different target values including two sets of observations. The observations used were the global avera...

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

    CERN Document Server

    de Wit, Julien; Langton, Jonathan; Laughlin, Gregory; Deming, Drake; Batygin, Konstantin; Fortney, Jonathan J

    2016-01-01

    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$500 to 1400 K as they absorb ~ 20% of the incoming stellar flux during the periastron passage, while the planet's rotation period is 93$\\pm_{35}^{85}$ hr, which exceeds the predicted ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Sisterson, D. L.

    2008-10-08

    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 July 1 - September 30, 2008, for the fixed sites. The AMF has been deployed to China, but the data have not yet been released. The fourth quarter comprises a total of 2,208 hours. The average exceeded our goal this quarter. The Site Access Request System is a web-based database used to track visitors to the fixed and mobile sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. HFE represents the AMF statistics for the Shouxian, China, deployment in 2008. FKB represents the AMF statistics for the Haselbach, Germany, past deployment in 2007. NIM represents the AMF statistics for the Niamey, Niger, Africa, past deployment in 2006. PYE represents just the AMF Archive statistics for the Point Reyes, California, past deployment in 2005. In addition, users who do not want to wait for data to be provided through the ACRF Archive can request a research account on the local site data system. The seven computers for the

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

    Science.gov (United States)

    Reichert, Andreas; Sussmann, Ralf; Rettinger, Markus

    2016-04-01

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

  17. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2008

    Energy Technology Data Exchange (ETDEWEB)

    Sisterson, DL

    2008-09-30

    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. The U.S. Department of Energy (DOE) 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 fourth quarter of FY 2008 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x 2,208), and for the Tropical Western Pacific (TWP) locale is 1,876.80 hours (0.85 x 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is not reported this quarter because the data have not yet been released from China to the DMF for processing. 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

  18. MAX-DOAS measurements of atmospheric trace gases in Ny-Ålesund - Radiative transfer studies and their application

    Science.gov (United States)

    Wittrock, F.; Oetjen, H.; Richter, A.; Fietkau, S.; Medeke, T.; Rozanov, A.; Burrows, J. P.

    2004-06-01

    A new approach to derive tropospheric concentrations of some atmospheric trace gases from ground-based UV/vis measurements is described. The instrument, referred to as the MAX-DOAS, is based on the well-known UV/vis instruments, which use the sunlight scattered in the zenith sky as the light source and the method of Differential Optical Absorption Spectroscopy (DOAS) to derive column amounts of absorbers like ozone and nitrogen dioxide. Substantial enhancements have been applied to this standard setup to use different lines of sight near to the horizon as additional light sources (MAX - multi axis). Results from measurements at Ny-Ålesund (79° N, 12° E) are presented and interpreted with the full-spherical radiative transfer model SCIATRAN. In particular, measurements of the oxygen dimer O4 which has a known column and vertical distribution in the atmosphere are used to evaluate the sensitivity of the retrieval to parameters such as multiple scattering, solar azimuth, surface albedo and refraction in the atmosphere and also to validate the radiative transfer model. As a first application, measurements of NO2 emissions from a ship lying in Ny-Ålesund harbour are presented. The results of this study demonstrate the feasibility of long term UV/vis multi axis measurement that can be used to derive not only column amounts of different trace gases but also some information on the vertical location of these absorbers.

  19. Atmospheric Radiation Measurement program climate research facility operations quarterly report July 1 - Sep. 30, 2009.

    Energy Technology Data Exchange (ETDEWEB)

    Sisterson, D. L.

    2009-10-15

    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 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. The U.S. Department of Energy (DOE) 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 fourth quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 ? 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 ? 2,208) and for the Tropical Western Pacific (TWP) locale is 1,876.8 hours (0.85 ? 2,208). The ARM Mobile Facility (AMF) was officially operational May 1 in Graciosa Island, the Azores, Portugal, so the OPSMAX time this quarter is 2,097.60 hours (0.95 x 2,208). 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 result from downtime (scheduled or unplanned) of the individual instruments. Therefore, data

  20. Raman lidar measurements of water vapor and aerosols during the atmospheric radiation measurement (ARM) remote clouds sensing (RCS) intensive observation period (IOP)

    Energy Technology Data Exchange (ETDEWEB)

    Melfi, S.H.; Starr, D.O`C.; Whiteman, D. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)] [and others

    1996-04-01

    The first Atmospheric Radiation Measurement (ARM) remote Cloud Study (RCS) Intensive Operations Period (IOP) was held during April 1994 at the Southern Great Plains (SGP) site. This experiment was conducted to evaluate and calibrate state-of-the-art, ground based remote sensing instruments and to use the data acquired by these instruments to validate retrieval algorithms developed under the ARM program.

  1. Atmospheric Radiation Measurement Program Climate Research Facility Operation quarterly report July 1 - September 30, 2010.

    Energy Technology Data Exchange (ETDEWEB)

    Sisterson, D. L.

    2010-10-26

    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 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. The U.S. Department of Energy (DOE) 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 fourth quarter of FY2010 for the Southern Great Plains (SGP) site is 2097.60 hours (0.95 2208 hours this quarter). The OPSMAX for the North Slope of Alaska (NSA) locale is 1987.20 hours (0.90 2208) and for the Tropical Western Pacific (TWP) locale is 1876.80 hours (0.85 2208). The first ARM Mobile Facility (AMF1) deployment in Graciosa Island, the Azores, Portugal, continues, so the OPSMAX time this quarter is 2097.60 hours (0.95 x 2208). 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 datastream. Data availability reported here refers to the average of the individual, continuous datastreams 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

  2. Application of synchrotron radiation for measurement of iron red-ox speciation in atmospherically processed aerosols

    Directory of Open Access Journals (Sweden)

    B. J. Majestic

    2007-01-01

    Full Text Available In this study, ambient atmospheric particulate matter (PM samples were collected using a size-resolved impactor sampler from three urban sites. The purpose of this study is to gain a better understanding of transformations of aerosol-bound iron as it is processed in the atmosphere. Thus, the aerosol samples were artificially aged to represent long-term transport (10 to 40 days or short-term transport (1 to 10 days and were measured for iron at several time points. At each time point, iron was measured in each size fraction using three different techniques; 1 inductively coupled plasma-mass spectrometry (ICPMS for total iron, 2 x-ray absorbance near edge structure (XANES spectroscopy for the measurement of total Fe(II and Fe(III, and 3 a wet-chemical method to measure soluble Fe(II and Fe(III. Prior to aging, the XANES spectroscopy results show that a majority (>60% for each size fraction of the total iron in the PM is in the form of Fe(III. Fe(III was shown to be a significant fraction of the soluble iron (sometimes > 50%, but the relative significance of Fe(III was found to vary depending on the site. Overall, the total soluble iron depended on the sampling site, but values ranged from less than 1% up to about 18% of the total iron. Over the course of the 40 day aging period, we found moderate changes in the relative Fe(II/Fe(III content. A slight increase was noted in the coarse (>2.5 μm fraction and a slight decrease in the 0.25 to 0.5 μm fraction. The soluble fraction generally showed (excepting one day a decrease of soluble Fe(II prior to 10 days of aging, followed by a relatively constant concentration. In the short-term transport condition, we found that the sub-micron fraction of soluble Fe(II spikes at 1 to 3 days of aging, then decreases to near the initial value at around 6 to 10 days. Very little change in soluble Fe(II was observed in the super-micron fraction. These results show that changes in the soluble iron fraction occur

  3. Technical progress report: Completion of spectral rotating shadowband radiometers and analysis of atmospheric radiation measurement spectral shortwave data

    Energy Technology Data Exchange (ETDEWEB)

    Michalsky, J.; Harrison, L. [State Univ. of New York, Albany, NY (United States)

    1996-04-01

    Our goal in the Atmospheric Radiation Measurement (ARM) Program is the improvement of radiation models used in general circulation models (GCMs), especially in the shortwave, (1) by providing improved shortwave radiometric measurements for the testing of models and (2) by developing methods for retrieving climatologically sensitive parameters that serve as input to shortwave and longwave models. At the Atmospheric Sciences Research Center (ASRC) in Albany, New York, we are acquiring downwelling direct and diffuse spectral irradiance, at six wavelengths, plus downwelling broadband longwave, and upwelling and downwelling broadband shortwave irradiances that we combine with National Weather Service surface and upper air data from the Albany airport as a test data set for ARM modelers. We have also developed algorithms to improve shortwave measurements made at the Southern Great Plains (SGP) ARM site by standard thermopile instruments and by the multifilter rotating shadowband radiometer (MFRSR) based on these Albany data sets. Much time has been spent developing techniques to retrieve column aerosol, water vapor, and ozone from the direct beam spectral measurements of the MFRSR. Additionally, we have had success in calculating shortwave surface albedo and aerosol optical depth from the ratio of direct to diffuse spectral reflectance.

  4. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1–September 30, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Sisterson, DL

    2010-10-15

    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 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. Application of synchrotron radiation for measurement of iron red-ox speciation in atmospherically processed aerosols

    Directory of Open Access Journals (Sweden)

    B. J. Majestic

    2007-01-01

    Full Text Available In this study, ambient atmospheric particulate matter samples were collected using a size-resolved impactor sampler from three urban sites. The purpose of this study is to gain a better understanding of transformations of aerosol-bound iron as it is processed in the atmosphere. Thus, the aerosol samples were artificially aged to represent long-term transport (10 to 40 days or short-term transport (1 to 10 days and were measured for iron at several time points. At each time point, iron was measured in each size fraction using three different techniques; 1 inductively coupled plasma-mass spectrometry (ICPMS for total iron, 2 x-ray absorbance near edge structure (XANES spectroscopy for the measurement of total Fe(II and Fe(III, and 3 a wet-chemical method to measure soluble Fe(II and Fe(III. Prior to aging, the XANES spectroscopy results show that a majority (>60% for each size fraction of the total iron in the PM is in the form of Fe(III. Fe(III was shown to be a significant fraction of the soluble iron (sometimes >50%, but the relative significance of Fe(III was found to vary depending on the site. Overall, the total soluble iron depended on the sampling site, but values ranged from less than 1% up to about 20% of the total iron. Over the course of the 40 day aging period, we found moderate changes in the relative Fe(II/Fe(III content. A slight increase was noted in the coarse (>2.5 µm fraction and a slight decrease in the 0.25 to 0.5 µm fraction. The soluble fraction generally showed (excepting one day a decrease of soluble Fe(II prior to 10 days of aging, followed by a relatively constant concentration. In the short-term transport condition, we found that the sub-micron fraction of soluble Fe(II spikes at 1 to 3 days of aging, then decreases to near the initial value at around 6 to 10 days. Very little change in soluble Fe(II was observed in the super-micron fraction.

  6. Improvements in Near-Terminator and Nocturnal Cloud Masks using Satellite Imager Data over the Atmospheric Radiation Measurement Sites

    Energy Technology Data Exchange (ETDEWEB)

    Trepte, Q.Z.; Minnis, P.; Heck, P.W.; Palikonda, R.

    2005-03-18

    Cloud detection using satellite measurements presents a big challenge near the terminator where the visible (VIS; 0.65 {micro}m) channel becomes less reliable and the reflected solar component of the solar infrared 3.9-{micro}m channel reaches very low signal-to-noise ratio levels. As a result, clouds are underestimated near the terminator and at night over land and ocean in previous Atmospheric Radiation Measurement (ARM) Program cloud retrievals using Geostationary Operational Environmental Satellite (GOES) imager data. Cloud detection near the terminator has always been a challenge. For example, comparisons between the CLAVR-x (Clouds from Advanced Very High Resolution Radiometer [AVHRR]) cloud coverage and Geoscience Laser Altimeter System (GLAS) measurements north of 60{sup o}N indicate significant amounts of missing clouds from AVHRR because this part of the world was near the day/night terminator viewed by AVHRR. Comparisons between MODIS cloud products and GLAS at the same regions also shows the same difficulty in the MODIS cloud retrieval (Pavolonis and Heidinger 2005). Consistent detection of clouds at all times of day is needed to provide reliable cloud and radiation products for ARM and other research efforts involving the modeling of clouds and their interaction with the radiation budget. To minimize inconsistencies between daytime and nighttime retrievals, this paper develops an improved twilight and nighttime cloud mask using GOES-9, 10, and 12 imager data over the ARM sites and the continental United States (CONUS).

  7. Climatology of aerosol and cloud optical properties at the Atmospheric Radiation Measurements Climate Research Facility Barrow and Atqasuk sites

    Science.gov (United States)

    Yin, Bangsheng; Min, Qilong

    2014-02-01

    The long-term measurements at the Barrow and Atqasuk sites have been processed to develop the climatology of aerosol and cloud properties at interannual, seasonal, and diurnal temporal scales. At the Barrow site, the surface temperature exhibits an increasing trend in both thawed and frozen seasons over the period studied here, about one decade. Corresponding to the warming, the snow melting day arrives earlier, and the non-snow-cover duration increases. Aerosol optical depth increased during 2001-2003 and 2005-2009 and decreased during 2003-2005. The liquid water path (LWP), cloud optical depth (COD), and cloud fraction exhibit apparently decreasing trends from 2002 to 2007 and increased significantly after 2008. In the frozen season, the arctic haze and ice clouds are dominant, while in the thawed season, the oceanic biogenic aerosols and liquid water clouds or mixed-phase clouds are dominant. The cloud droplet effective radius during the thawed season is larger than that during the frozen season. The diurnal variations of aerosol and cloud-related atmospheric properties are not obvious at these two sites. During the sunshine periods, the aerosol has a cooling effect on the surface through direct aerosol radiative forcing. In the frozen season, clouds have a positive impact on the net surface radiation, and the water vapor path, LWP, and COD have good positive correlations with the surface temperature, suggesting that the cloud radiation feedback is positive. In the thawed season, clouds have a negative impact on the net surface radiation.

  8. Finite Difference Radiative Transfer Model Calculations Compared to Measurements at the Top and Bottom of the Atmosphere

    Science.gov (United States)

    LeCroy, Stuart R.; Whitlock, Charles H.; Suttles, John T.

    1997-01-01

    A finite difference radiative transfer program was developed to handle most anisotropic scattering and reflectance problems encountered in the Earth's atmospheric system. The model has been used to reproduce the radiance received by both satellite and ground based radiation measuring instruments. It accurately replicates the radiance measured by both narrow and wide field-of-view instruments with either narrow or broadband wavelength ranges located on the surface and at satellite altitudes. The output of the finite difference code is compared to the measurements by surface pyranometers and a spectroradiometer aboard a high flying aircraft. The program output is also compared to ERBE measurements aboard the ERBS and NOAA-9 satellites as well as the visible bands aboard the GOES-6 and GOES-7 satellites and AVHRR bands 1 and 2 of the NOAA-9 and NOAA-1 1 satellites. The model is within 0.2 % of the radiance received by pyranometers, within 0.6 % of the ERBE radiances, and within 3 % of the radiances measured by the visible bands of the GOES and NOAA AVHRR radiometers.

  9. An Analysis of Satellite, Radiosonde, and Lidar Observations of Upper Tropospheric Water Vapor from the Atmospheric Radiation Measurement Program

    Energy Technology Data Exchange (ETDEWEB)

    Soden, Brian J.; Turner, David D.; Lesht, B. M.; Miloshevich, Larry M.

    2004-02-25

    To improve our understanding of the distribution and radiative effects of water vapor, the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program has conducted a series of coordinated water vapor Intensive Observational Periods (IOPs). This study uses observations collected from four ARM IOPs to accomplish two goals: first, we compare radiosonde and Raman lidar observations of upper tropospheric water vapor with co-located geostationary satellite radiances at 6.7 micrometers. During all four IOPs, we find excellent agreement between the satellite and Raman lidar observations of upper tropospheric humidity with systematic differences of ~10%. In contrast, radiosondes equipped with Vaisala sensors are shown to be systematically drier in the upper troposphere by ~40% relative to both the lidar and satellite measurements. Second, we assess the performance of various "correction" strategies designed to rectify known deficiencies in the radiosonde measurements. It is shown that existing methods for correcting the radiosonde dry bias, while effective in the lower troposphere, offer little improvement in the upper troposphere. An alternative method based on variational assimilation of satellite radiances is presented and, when applied to the radiosonde measurements, is shown to significantly improve their agreement with coincident Raman lidar observations. It is suggested that a similar strategy could be used to improve the quality of the global historical record of radiosonde water vapor observations during the satellite era.

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

    OpenAIRE

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

    2016-01-01

    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...

  11. Analysis of the Uncertainty in Wind Measurements from the Atmospheric Radiation Measurement Doppler Lidar during XPIA: Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Newsom, Rob [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-01

    In March and April of 2015, the ARM Doppler lidar that was formerly operated at the Tropical Western Pacific site in Darwin, Australia (S/N 0710-08) was deployed to the Boulder Atmospheric Observatory (BAO) for the eXperimental Planetary boundary-layer Instrument Assessment (XPIA) field campaign. The goal of the XPIA field campaign was to investigate methods of using multiple Doppler lidars to obtain high-resolution three-dimensional measurements of winds and turbulence in the atmospheric boundary layer, and to characterize the uncertainties in these measurements. The ARM Doppler lidar was one of many Doppler lidar systems that participated in this study. During XPIA the 300-m tower at the BAO site was instrumented with well-calibrated sonic anemometers at six levels. These sonic anemometers provided highly accurate reference measurements against which the lidars could be compared. Thus, the deployment of the ARM Doppler lidar during XPIA offered a rare opportunity for the ARM program to characterize the uncertainties in their lidar wind measurements. Results of the lidar-tower comparison indicate that the lidar wind speed measurements are essentially unbiased (~1cm s-1), with a random error of approximately 50 cm s-1. Two methods of uncertainty estimation were tested. The first method was found to produce uncertainties that were too low. The second method produced estimates that were more accurate and better indicators of data quality. As of December 2015, the first method is being used by the ARM Doppler lidar wind value-added product (VAP). One outcome of this work will be to update this VAP to use the second method for uncertainty estimation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Murcray, F.; Stephen, T.; Kosters, J. [Univ. of Denver, CO (United States)

    1996-04-01

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

  13. High spectral resolution fourier transform infrared instruments for the Atmospheric Radiation Measurement Program

    International Nuclear Information System (INIS)

    Major accomplishments of the Atmospheric Emitted Radiance Interferometer (AERI) Instrument Development Program (IDP) effort have been to (1) develop and extensively test a new radiometric calibration subsystem with improved accuracy and robustness; (2) interact with Bomem, Inc., leading to the development of a two-channel interferometer with the required software characteristics; (3) develop new operational control software and network interfaces; (4) develop new analysis techniques to handle the complete calibration, including a detector nonlinearity correction, wavelength scale standardization, and a finite field-of-view correction; (5) integrate the required hardware, operational control software, and analysis software into a complete system which interfaces to the CART data system and operates remotely; and (6) perform extensive field testing of the AERI system prototype

  14. The DOE Atmospheric Radiation Measurement Program's LES ARM Symbiotic Simulation and Observation (LASSO) Workflow: Initialization, Forcing and Multiscale Data Assimilation

    Science.gov (United States)

    Li, Z.; Cheng, X.; Gustafson, W. I., Jr.; Xiao, H.; Endo, S.; Vogelmann, A. M.; Toto, T.

    2015-12-01

    The Department of Energy Atmospheric Radiation Measurement (ARM) Program is developing a routine large-eddy simulation (LES) modeling framework at the ARM Climate Research Facility sites, known as the "LES ARM Symbiotic Simulation and Observation" (LASSO) Workflow. The routine simulations will be assessed using comprehensive ARM observations of the atmosphere and land-surface states, particularly cloud observations. Since small changes in thermodynamic profiles can manifest large changes in cloud properties, successful simulations require careful initialization, appropriate forcing, and possibly suitable lateral boundary conditions. We use a multiscale data assimilation (MS-DA) system as a major methodology for producing forcing datasets required by the LES modeling. The MS-DA will be implemented in the regional Weather Research and Forecasting (WRF) model at a cloud resolving resolution (~1 km). MS-DA leverages existing reanalyses (e.g., the NCEP North American Regional Reanalysis, NARR) and operational forecasting products (e.g. the North American Mesoscale Forecast System, NAM; the High-Resolution Rapid Refresh, HRRR) products, and takes advantage of ARM observations to directly constrain the spectra of horizontal scales down to a few km. The analysis from the MS-DA allows deriving initial conditions and forcing datasets for a range of spatial and temporal scales, developing hydrometeor forcing, exploring time-varying boundary conditions, and diagnosing other needed thermodynamic variables. It is stressed that the datasets from the MS-DA are integrated with datasets from other sources to form ensembles to account for uncertainties. The methodologies, implementation and evaluations are presented.

  15. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 - September 30, 2005

    Energy Technology Data Exchange (ETDEWEB)

    Sisterson, DL

    2005-09-30

    Description. Individual raw data streams from instrumentation at the ACRF fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at 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 DOE 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 2,097.6 hours (0.95 × 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) site is 1,987.2 hours (0.90 × 2,208), and that for the Tropical Western Pacific (TWP) site is 1,876.8 hours (0.85 × 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,097.6 hours (0.95 × 2,208). 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 ACRF 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 represents the average percent of the time (24 hours per day, 92 days for this quarter) the instruments were operating

  16. Study of natural energy system and downward atmospheric radiation. Part 1. Outline on measurement and result on downward atmospheric radiation; Shizen energy system to tenku hosharyo no kansoku kenkyu. 1. Kisho kansoku gaiyo to tenku hosharyo no kansoku kekka

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, K. [Kogakuin University, Tokyo (Japan); Masuoka, Y. [Yokogawa Architects and Engineers, Inc., Tokyo (Japan)

    1996-10-27

    For the study of a natural energy system taking advantage of radiation cooling, a simplified method for estimating downward atmospheric radiation quantities was examined, using observation records supplied from Hachioji City, Aerological Observatory in Tsukuba City, and four other locations. Downward atmospheric radiation quantities are closely related to partial vapor pressure in the atmosphere. Because partial vapor pressure changes according to the season, it was classified into two, for summer and for winter, and was referred to downward atmospheric radiation quantities for the establishment of their correlationships. Downward atmospheric radiation quantities were predicted on the basis of meteorological factors such as partial vapor pressure and free air temperature. Accuracy was examined of the simplified estimation equation for downward atmospheric radiation that had been proposed. A multiple regression analysis was carried out for calculating constants for the estimation equation, using partial vapor pressure, Stefan-Boltzmann constant, and free air dry-bulb absolute temperature, all closely correlated with atmospheric downward radiation quantities. Accuracy improved by time-based classification. At night, use of SAT (equivalent free air temperature) produced more accurate estimation. Though dependent upon local characteristics of the observation spot, the estimation equation works effectively. 10 refs., 10 figs., 3 tabs.

  17. Contributions of the Atmospheric Radiation Measurement (ARM) Program and the ARM Climate Research Facility to the U.S. Climate Change Science Program

    Energy Technology Data Exchange (ETDEWEB)

    SA Edgerton; LR Roeder

    2008-09-30

    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. The 2007 assessment (AR4) by the Intergovernmental Panel on Climate Change (IPCC) reports a substantial range among GCMs in climate sensitivity to greenhouse gas emissions. The largest contributor to this range lies in how different models handle changes in the way clouds absorb or reflect radiative energy in a changing climate (Solomon et al. 2007). In 1989, the U.S. Department of Energy (DOE) Office of Science created the Atmospheric Radiation Measurement (ARM) Program within the Office of Biological and Environmental Research (BER) 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 address this problem, BER has adopted a unique two-pronged approach: * The ARM Climate Research Facility (ACRF), a scientific user facility for obtaining long-term measurements of radiative fluxes, cloud and aerosol properties, and related atmospheric characteristics in diverse climate regimes. * The ARM Science Program, focused on the analysis of ACRF data to address climate science issues associated with clouds, aerosols, and radiation, and to improve GCMs. This report describes accomplishments of the BER ARM Program toward addressing the primary uncertainties related to climate change prediction as identified by the IPCC.

  18. Atmospheric thermal structure and cloud features in the southern hemisphere of Venus as retrieved from VIRTIS/VEX radiation measurements

    Science.gov (United States)

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

    2014-04-01

    Thermal structure and cloud features in the atmosphere of Venus are investigated using spectroscopic nightside measurements recorded by the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) aboard ESA’s Venus Express mission in the moderate resolution infrared mapping channel (M-IR, 1-5 μm). New methodical approaches and retrieval results for the northern hemisphere have been recently described by Haus et al. (Haus, R., Kappel, D., Arnold, G. [2013]. Planet. Space Sci. 89, 77-101. http://dx.doi.org/10.1016/j.pss.2013.09.020). Now, southern hemisphere maps of mesospheric temperature and cloud parameter fields are presented that cover variations with altitude, latitude, local time, and mission time. Measurements from the entire usable data archive are utilized comprising radiation spectra recorded during eight Venus solar days between April 2006 and October 2008. Zonal averages of retrieved temperature altitude profiles in both hemispheres are very similar and give evidence of global N-S axial symmetry of atmospheric temperature structure. Cold collar and warmer polar vortex regions exhibit the strongest temperature variability with standard deviations up to 8.5 K at 75°S and 63 km altitude compared with about 1.0 K at low and mid latitudes above 75 km. The mesospheric temperature field strongly depends on local time. At altitudes above about 75 km, the atmosphere is warmer in the second half of night, while the dawn side at lower altitudes is usually colder than the dusk side by about 8 K. Local minimum temperature of 220 K occurs at 03:00 h local time at 65 km and 60°S. Temperature standard deviation at polar latitudes is particularly large near midnight. Temperature variability with solar longitude is forced by solar thermal tides with a dominating diurnal component. The influence of observed cloud parameter changes on retrieved mesospheric zonal average temperature structure is moderate and does not exceed 2-3 K at altitudes between 60 and 75 km

  19. Atmospheric radiative transfer simulation for atmospheric correction of remote sensing data

    Institute of Scientific and Technical Information of China (English)

    Yunfei Bao; Shengbo Chen

    2006-01-01

    The radiance leaving the earth-atmosphere system which can be sensed by a satellite borne radiometer is the sum of radiation emission from the earth surface and each atmospheric level that are transmitted to the top of the atmosphere. The radiation emission from the earth surface and the radiance of each atmospheric level can be separated from the radiance at the top the atmospheric level measured by a satellite borne radiometer. However, it is very difficult to measure the atmospheric radiance, especially the synchronous measurement with the satellite. Thus some atmospheric radiative transfer models have been developed to provide many options for modeling atmospheric radiation transport, such as LOWTRAN, MODTRAN, 6S, FASCODE, LBLRTM, SHARC, and SAMM. Meanwhile, these models can support the detailed detector system design, the optimization and evaluation of satellite mission parameters, and the data processing procedures. As an example, the newly atmospheric radiative transfer models, MODTRAN will be compared with other models after the atmospheric radiative transfer is described. And the atmospheric radiative transfer simulation procedures and their applications to atmospheric transmittance, retrieval of atmospheric elements, and surface parameters, will also be presented.

  20. Determination of radiation doses caused by release into the atmosphere by nuclear power plants, based on measurement of emission and immission

    International Nuclear Information System (INIS)

    The radiation impact of nuclear facilities, and the nuclear power plants as well, can be determined by using two methods. The first one calculates the dose of critical group of population based on the release, meteorological and hydrological parameters. The second method gives an estimate of the additional dose caused by the nuclear facility from the radiological measurements in the environment. This article compares this two methods for the release in the atmosphere, and gives an estimate of the relative error. The comparison can be applied for cases when the atmospheric pollution is released from a point type source, so for the conventional power plants as well. (author)

  1. Solar and thermal radiation in the Venus atmosphere

    Science.gov (United States)

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

    1985-01-01

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

  2. MAX-DOAS measurements of atmospheric trace gases in Ny-Ålesund - Radiative transfer studies and their application

    OpenAIRE

    Wittrock, F.; Oetjen, H.; Richter, A.; Fietkau, S.; Medeke, T.; Rozanov, A.; Burrows, J.P.

    2004-01-01

    International audience A new approach to derive tropospheric concentrations of some atmospheric trace gases from ground-based UV/vis measurements is described. The instrument, referred to as the MAX-DOAS, is based on the well-known UV/vis instruments, which use the sunlight scattered in the zenith sky as the light source and the method of Differential Optical Absorption Spectroscopy (DOAS) to derive column amounts of absorbers like ozone and nitrogen dioxide. Substantial enhancements have ...

  3. Atmospheric effects on radiation reflected from soil and vegetation as measured by orbital sensors using various scanning directions

    Science.gov (United States)

    Slater, P. N.; Jackson, R. D.

    1982-01-01

    Ground-measured spectral reflectance data for Avondale loam and drought-stressed and unstressed wheat were converted into digital counts for spectral bands 5 and 7 of the Landsat Multispectral Scanner System (MSS). For dry loam, the differences between ratios of MSS bands 7-5 as determined from space and from ground level measurements were 2.3 percent for clear and 5.6 percent for turbid atmospheric conditions. By contrast, for wet loam the differences were 10.4 and 29.5 percent. It is found that atmospheric conditions may cause a delay of from 3 to 7 days in the discrimination between drought-stressed and unstressed wheat. For oblique angle observations the atmospheric modification of ground-measured reflectances increased with angle at a greater rate in the 0/180 deg azimuth than in the 90/270 deg azimuth. Implications of this result are discussed for oblique angle Systeme Probatoire d'Observation de la Terre (SPOT), Mapsat, future multispectral linear array system imagery, and wide-angle imagery collected from scanners in high-altitude aircraft.

  4. RADIATION HYDRODYNAMICS OF HOT JUPITER ATMOSPHERES

    International Nuclear Information System (INIS)

    Radiative transfer in planetary atmospheres is usually treated in the static limit, i.e., neglecting atmospheric motions. We argue that hot Jupiter atmospheres, with possibly fast (sonic) wind speeds, may require a more strongly coupled treatment, formally in the regime of radiation hydrodynamics. To lowest order in v/c, relativistic Doppler shifts distort line profiles along optical paths with finite wind velocity gradients. This leads to flow-dependent deviations in the effective emission and absorption properties of the atmospheric medium. Evaluating the overall impact of these distortions on the radiative structure of a dynamic atmosphere is non-trivial. We present transmissivity and systematic equivalent width excess calculations which suggest possibly important consequences for radiation transport in hot Jupiter atmospheres. If winds are fast and bulk Doppler shifts are indeed important for the global radiative balance, accurate modeling and reliable data interpretation for hot Jupiter atmospheres may prove challenging: it would involve anisotropic and dynamic radiative transfer in a coupled radiation-hydrodynamical flow. On the bright side, it would also imply that the emergent properties of hot Jupiter atmospheres are more direct tracers of their atmospheric flows than is the case for solar system planets. Radiation hydrodynamics may also influence radiative transfer in other classes of hot exoplanetary atmospheres with fast winds.

  5. Radiation-Hydrodynamics of Hot Jupiter Atmospheres

    CERN Document Server

    Menou, Kristen

    2009-01-01

    Radiative transfer in planetary atmospheres is usually treated in the static limit, i.e., neglecting atmospheric motions. We argue that hot Jupiter atmospheres, with possibly fast (sonic) wind speeds, may require a more strongly coupled treatment, formally in the regime of radiation-hydrodynamics. To lowest order in v/c, relativistic Doppler shifts distort line profiles along optical paths with finite wind velocity gradients. This leads to flow-dependent deviations in the effective emission and absorption properties of the atmospheric medium. Evaluating the overall impact of these distortions on the radiative structure of a dynamic atmosphere is non-trivial. We present transmissivity and systematic equivalent width excess calculations which suggest possibly important consequences for radiation transport in hot Jupiter atmospheres. If winds are fast and bulk Doppler shifts are indeed important for the global radiative balance, accurate modeling and reliable data interpretation for hot Jupiter atmospheres may p...

  6. Model Assessment of the Ability of MODIS to Measure Top-of-Atmosphere Direct Radiative Forcing from Smoke Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Remer, L. A.; Kaufman, Yoram J.; Levin, Zev; Ghan, Steven J.

    2002-02-01

    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. We narrow the discussion to cloud free direct forcing. 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 1.2 to 2.2 Wm-2 (16-60%) 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.

  7. Airborne instruments to measure atmospheric aerosol particles, clouds and radiation: A cook's tour of mature and emerging technology

    Science.gov (United States)

    Baumgardner, D.; Brenguier, J. L.; Bucholtz, A.; Coe, H.; DeMott, P.; Garrett, T. J.; Gayet, J. F.; Hermann, M.; Heymsfield, A.; Korolev, A.; Krämer, M.; Petzold, A.; Strapp, W.; Pilewskie, P.; Taylor, J.; Twohy, C.; Wendisch, M.; Bachalo, W.; Chuang, P.

    2011-10-01

    An overview is presented of airborne systems for in situ measurements of aerosol particles, clouds and radiation that are currently in use on research aircraft around the world. Description of the technology is at a level sufficient for introducing the basic principles of operation and an extensive list of references for further reading is given. A number of newer instruments that implement emerging technology are described and the review concludes with a description of some of the most important measurement challenges that remain. This overview is a synthesis of material from a reference book that is currently in preparation and that will be published in 2012 by Wiley.

  8. Cloud droplet size and liquid water path retrievals from zenith radiance measurements: examples from the Atmospheric Radiation Measurement Program and the Aerosol Robotic Network

    Directory of Open Access Journals (Sweden)

    J. C. Chiu

    2012-11-01

    Full Text Available The ground-based Atmospheric Radiation Measurement Program (ARM and NASA Aerosol Robotic Network (AERONET routinely monitor clouds using zenith radiances at visible and near-infrared wavelengths. Using the transmittance calculated from such measurements, we have developed a new retrieval method for cloud effective droplet size and conducted extensive tests for non-precipitating liquid water clouds. The underlying principle is to combine a liquid-water-absorbing wavelength (i.e., 1640 nm with a non-water-absorbing wavelength for acquiring information on cloud droplet size and optical depth. For simulated stratocumulus clouds with liquid water path less than 300 g m−2 and horizontal resolution of 201 m, the retrieval method underestimates the mean effective radius by 0.8 μm, with a root-mean-squared error of 1.7 μm and a relative deviation of 13%. For actual observations with a liquid water path less than 450 g m−2 at the ARM Oklahoma site during 2007–2008, our 1.5-min-averaged retrievals are generally larger by around 1 μm than those from combined ground-based cloud radar and microwave radiometer at a 5-min temporal resolution. We also compared our retrievals to those from combined shortwave flux and microwave observations for relatively homogeneous clouds, showing that the bias between these two retrieval sets is negligible, but the error of 2.6 μm and the relative deviation of 22% are larger than those found in our simulation case. Finally, the transmittance-based cloud effective droplet radii agree to better than 11% with satellite observations and have a negative bias of 1 μm. Overall, the retrieval method provides reasonable cloud effective radius estimates, which can enhance the cloud products of both ARM and AERONET.

  9. Cloud droplet size and liquid water path retrievals from zenith radiance measurements: examples from the Atmospheric Radiation Measurement Program and the Aerosol Robotic Network

    Directory of Open Access Journals (Sweden)

    J. C. Chiu

    2012-08-01

    Full Text Available The ground-based Atmospheric Radiation Measurement Program (ARM and NASA Aerosol Robotic Network (AERONET routinely monitor clouds using zenith radiances at visible and near-infrared wavelengths. Using the transmittance calculated from such measurements, we have developed a new retrieval method for cloud effective droplet size and conducted extensive tests for non-precipitating liquid water clouds. The underlying principle is to combine a water-absorbing wavelength (i.e. 1640 nm with a non-water-absorbing wavelength for acquiring information on cloud droplet size and optical depth. For simulated stratocumulus clouds with liquid water path less than 300 g m−2 and horizontal resolution of 201 m, the retrieval method underestimates the mean effective radius by 0.8 μm, with a root-mean-squared error of 1.7 μm and a relative deviation of 13%. For actual observations with a liquid water path less than 450 g m−2 at the ARM Oklahoma site during 2007–2008, our 1.5 min-averaged retrievals are generally larger by around 1 μm than those from combined ground-based cloud radar and microwave radiometer at a 5 min temporal resolution. We also compared our retrievals to those from combined shortwave flux and microwave observations for relatively homogeneous clouds, showing that the bias between these two retrieval sets is negligible, but the error of 2.6 μm and the relative deviation of 22% are larger than those found in our simulation case. Finally, the transmittance-based cloud effective droplet radii agree to better than 11% with satellite observations and have a negative bias of 1 μm. Overall, the retrieval method provides reasonable cloud effective radius estimates, which can enhance the cloud products of both ARM and AERONET.

  10. Cloud Droplet Size and Liquid Water Path Retrievals From Zenith Radiance Measurements: Examples From the Atmospheric Radiation Measurement Program and the Aerosol Robotic Network

    Science.gov (United States)

    Chiu, J. C.; Marshak, A.; Huang, C.-H.; Varnai, T.; Hogan, R. J.; Giles, D. M.; Holben, B. N.; Knyazikhin, Y.; O'Connor, E. J.; Wiscombe, W. J.

    2012-01-01

    The ground-based Atmospheric Radiation Measurement Program (ARM) and NASA Aerosol Robotic Network (AERONET) routinely monitor clouds using zenith radiances at visible and near-infrared wavelengths. Using the transmittance calculated from such measurements, we have developed a new retrieval method for cloud effective droplet size and conducted extensive tests for non-precipitating liquid water clouds. The underlying principle is to combine a water-absorbing wavelength (i.e. 1640 nm) with a nonwater-absorbing wavelength for acquiring information on cloud droplet size and optical depth. For simulated stratocumulus clouds with liquid water path less than 300 g/sq m and horizontal resolution of 201m, the retrieval method underestimates the mean effective radius by 0.8 m, with a root-mean-squared error of 1.7 m and a relative deviation of 13 %. For actual observations with a liquid water path less than 450 gm.2 at the ARM Oklahoma site during 2007-2008, our 1.5 min-averaged retrievals are generally larger by around 1 m than those from combined ground-based cloud radar and microwave radiometer at a 5min temporal resolution. We also compared our retrievals to those from combined shortwave flux and microwave observations for relatively homogeneous clouds, showing that the bias between these two retrieval sets is negligible, but the error of 2.6 m and the relative deviation of 22% are larger than those found in our simulation case. Finally, the transmittance-based cloud effective droplet radii agree to better than 11% with satellite observations and have a negative bias of 1 m. Overall, the retrieval method provides reasonable cloud effective radius estimates, which can enhance the cloud products of both ARM and AERONET.

  11. Measurement of the Atmospheric $\

    CERN Document Server

    Aartsen, M G; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beattie, K; Beatty, J J; Bechet, S; Tjus, J Becker; Becker, K -H; Bell, M; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose1, D; Boser, S; Botner, O; Brayeur, L; Brown, A M; Bruijn, R; Brunner, J; Buitink, S; Carson, M; Casey, J; Casier, M; Chirkin, D; Christy, B; Clark, K; Clevermann, F; Cohen, S; Cowen, D F; Silva, A H Cruz; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Diaz-Velez, J C; Dreyer, J; Dumm, J P; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Engdegard, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glusenkamp, T; Goldschmidt, A; Golup, G; Goodman, J A; Gora, D; Grant, D; Gross, A; Grullon, S; Gurtner, M; Ha, C; Ismail, A Haj; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heimann, P; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Japaridze, G S; Jlelati, O; Kappes, A; Karg, T; Karle, A; Kiryluk, J; Kislat, F; Klas, J; Klein, S R; Kohne, J -H; Kohnen, G; Kolanoski, H; Kopke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lauer, R; Lesiak-Bzdak, M; Lunemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Meszaros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Panknin, S; Paul, L; Pepper, J A; Heros, C Perez de los; Pieloth, D; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Radel, L; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schoneberg, S; Schonherr, L; Schonwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Seo, S H; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soiron, M; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stoss, A; Strahler, E A; Strom, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge1, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Wasserman, R; Weaver, Ch; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zilles, A; Zoll, M

    2012-01-01

    We report the first observation in a high energy neutrino telescope of cascades induced by atmospheric electron neutrinos and by neutral current interactions of atmospheric neutrinos of all flavors. Using data recorded during the first year of operation of IceCube's DeepCore low energy extension, a sample of 1029 events is observed in 281 days of data. The number of observed cascades is $N_{\\rm cascade} = 496 \\pm 66 (stat.) \\pm 88(syst.)$ and the rest of the sample consists of residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is determined in the energy range between approximately 80 GeV and 6 TeV and is consistent with models of atmospheric neutrinos.

  12. The Radiation Environment of Exoplanet Atmospheres

    Directory of Open Access Journals (Sweden)

    Jeffrey L. Linsky

    2014-10-01

    Full Text Available Exoplanets are born and evolve in the radiation and particle environment created by their host star. The host star’s optical and infrared radiation heats the exoplanet’s lower atmosphere and surface, while the ultraviolet, extreme ultraviolet and X-radiation control the photochemistry and mass loss from the exoplanet’s upper atmosphere. Stellar radiation, especially at the shorter wavelengths, changes dramatically as a host star evolves leading to changes in the planet’s atmosphere and habitability. This paper reviews the present state of our knowledge concerning the time-dependent radiation emitted by stars with convective zones, that is stars with spectral types F, G, K, and M, which comprise nearly all of the host stars of detected exoplanets.

  13. Tests of Exoplanet Atmospheric Radiative Transfer Codes

    Science.gov (United States)

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

    2016-10-01

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

  14. Atmospheres and radiating surfaces of neutron stars

    CERN Document Server

    Potekhin, A Y

    2014-01-01

    The beginning of the 21st century was marked by a breakthrough in the studies of thermal radiation of neutron stars. Observations with modern space telescopes have provided a wealth of valuable information. Being correctly interpreted, this information can elucidate physics of superdense matter in the interiors of these stars. The theory of formation of thermal spectra of neutron stars is based on the physics of plasmas and radiative processes in stellar photospheres. It provides the framework for interpretation of observational data and for extracting neutron-star parameters from these data. This paper presents a review of the current state of the theory of surface layers of neutron stars and radiative processes in these layers, with the main focus on the neutron stars that possess strong magnetic fields. In addition to the conventional deep (semi-infinite) atmospheres, radiative condensed surfaces of neutron stars and "thin" (finite) atmospheres are also considered.

  15. Multiple equilibria in radiative-convective atmospheres

    OpenAIRE

    Rennó, Nilton O.

    2011-01-01

    A one-dimensional, radiative-convective model is used to study the equilibria conditions of moist atmospheres. We show that when the hydrologic cycle is included in the model a subcritical bifurcation occurs, leading to 2 linearly stable solutions to the radiative-convective equilibria. In this case, when the net forcing is larger than a critical value, two equilibria are possible. Furthermore, a finite amplitude instability can lead to a runaway greenhouse regime when the solar forcing is la...

  16. EXOMARS IRAS (DOSE) radiation measurements.

    Science.gov (United States)

    Federico, C.; Di Lellis, A. M.; Fonte, S.; Pauselli, C.; Reitz, G.; Beaujean, R.

    The characterization and the study of the radiations on their interaction with organic matter is of great interest in view of the human exploration on Mars. The Ionizing RAdiation Sensor (IRAS) selected in the frame of the ExoMars/Pasteur ESA mission is a lightweight particle spectrometer combining various techniques of radiation detection in space. It characterizes the first time the radiation environment on the Mars surface, and provide dose and dose equivalent rates as precursor information absolutely necessary to develop ways to mitigate the radiation risks for future human exploration on Mars. The Martian radiation levels are much higher than those found on Earth and they are relatively low for space. Measurements on the surface will show if they are similar or not to those seen in orbit (modified by the presence of ``albedo'' neutrons produced in the regolith and by the thin Martian atmosphere). IRAS consists of a telescope based on segmented silicon detectors of about 40\\userk\\milli\\metre\\user;k diameter and 300\\user;k\\micro\\metre\\user;k thickness, a segmented organic scintillator, and of a thermoluminescence dosimeter. The telescope will continuously monitor temporal variation of the particle count rate, the dose rate, particle and LET (Linear Energy Transfer) spectra. Tissue equivalent BC430 scintillator material will be used to measure the neutron dose. Neutrons are selected by a criteria requiring no signal in the anti-coincidence. Last, the passive thermoluminescence dosimeter, based on LiF:Mg detectors, regardless the on board operation timing, will measure the total dose accumulated during the exposure period and due to beta and gamma radiation, with a responsivity very close to that of a human tissue.

  17. Measurement of gravitational radiation

    International Nuclear Information System (INIS)

    The present article first describes some possible principles and mechanisms for detecting the gravitational radiation, and then outlines measuring techniques required for its detection. Some major issues concerned, present status of research and future prospects are also discussed. There are two possible detectors. One is the resonance type detector, which uses an elastic body with a considerable mass as antenna to catch the gravitational radiation. Gravitational radiation entering the elastic body causes an internal stress, resulting in vibration. Thus, a resonance type detector consists of an elastic body acting as antenna to catch gravitational radiation, and a transducer that converts the mechanical vibration of the antenna into electrical signals. The antenna and transducer should be contained in a vacuum highly protected from external acoustic and electromagnetic noise as well as external vibrations. Another possible detector uses a laser interferometer to detect a change in the distance between two bodies caused by gravitational radiation. Some techniques that could provide a tool for measuring such extremely small vibrations are also described and discussed. (N.K.)

  18. Origin of Hawking Radiation: Firewall or Atmosphere?

    CERN Document Server

    Kim, Wontae

    2016-01-01

    The Unruh vacuum not admitting any outgoing flux at the horizon implies that the origin of the outgoing Hawking radiation would be the atmosphere of a near-horizon quantum region without resort to the firewall; however, the existence of the firewall of superplanckian excitations at the horizon might be supported by the infinite Tolman temperature of the infinitely blueshifted Hawking temperature at the horizon. Using an exactly soluble model, we show that the firewall necessarily emerges out of the Unruh vacuum such that the Tolman temperature in the Unruh vacuum is divergent in essence due to the infinitely blueshifted negative ingoing flux crossing the horizon rather than the outgoing flux. It is also shown that the outgoing Hawking radiation in the Unruh vacuum indeed originates from the atmosphere, not just at the horizon, which is of no relevance to the infinite blueshift. Consequently, we find that the firewall induced from the infinite Tolman temperature and the Hawking radiation coming from the atmosp...

  19. Airborne Atmospheric Aerosol Measurement System

    Science.gov (United States)

    Ahn, K.; Park, Y.; Eun, H.; Lee, H.

    2015-12-01

    It is important to understand the atmospheric aerosols compositions and size distributions since they greatly affect the environment and human health. Particles in the convection layer have been a great concern in global climate changes. To understand these characteristics satellite, aircraft, and radio sonde measurement methods have usually been used. An aircraft aerosol sampling using a filter and/or impactor was the method commonly used (Jay, 2003). However, the flight speed particle sampling had some technical limitations (Hermann, 2001). Moreover, the flight legal limit, altitude, prohibited airspace, flight time, and cost was another demerit. To overcome some of these restrictions, Tethered Balloon Package System (T.B.P.S.) and Recoverable Sonde System(R.S.S.) were developed with a very light optical particle counter (OPC), impactor, and condensation particle counter (CPC). Not only does it collect and measure atmospheric aerosols depending on altitudes, but it also monitors the atmospheric conditions, temperature, humidity, wind velocity, pressure, GPS data, during the measurement (Eun, 2013). In this research, atmospheric aerosol measurement using T.B.P.S. in Ansan area is performed and the measurement results will be presented. The system can also be mounted to an unmanned aerial vehicle (UAV) and create an aerial particle concentration map. Finally, we will present measurement data using Tethered Balloon Package System (T.B.P.S.) and R.S.S (Recoverable Sonde System).

  20. Impacts of the triggering function of cumulus parameterization on warm-season diurnal rainfall cycles at the Atmospheric Radiation Measurement Southern Great Plains site

    Science.gov (United States)

    Wang, Yi-Chi; Pan, Hua-Lu; Hsu, Huang-Hsiung

    2015-10-01

    In this study, we investigated the impacts of the triggering function of the deep convection scheme on diurnal rainfall variation in the middle latitudes by using the single-column version of the Community Atmospheric Model (SCAM). Using the climate statistics of a long-term ensemble analysis of SCAM simulations, we quantified and validated the diurnal rainfall climatological regimes at the Atmospheric Radiation Measurement Southern Great Plains (SGP) site. The results showed that the averaged diurnal rainfall cycle simulated using the default Zhang-Mcfarlane (ZM) scheme of the SCAM peaks near noon, which is far earlier than the observed nighttime peak phase. This bias was due to the ZM scheme, which produced spurious daytime rainfall, even during days in which only light rainfall was observed. By contrast, using a weather-focused scheme, the Simplified Arakawa-Schubert (SAS) scheme, we successfully simulated the nocturnal peak of the diurnal cycle. Experiments conducted on the ZM and SAS schemes featuring different triggering functions revealed that the relaxation of launching parcels above the planetary boundary layer (PBL) and the inclusion of convective inhibition (CIN) were crucial designs for the model to capture the nocturnal rainfall events of the SGP. The inclusion of CIN reduces spurious weak convective events, and the allowance of launching parcels being above the PBL better captures convective cloud base. The results of this study highlight the modulatory effect of low-level inhomogeneity on the diurnal variation of convection over midlatitudes and the importance of the triggering function of the deep convection scheme in capturing those variations.

  1. Satellite observation of atmospheric nuclear gamma radiation

    Science.gov (United States)

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

    1989-01-01

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

  2. Mobile Instruments Measure Atmospheric Pollutants

    Science.gov (United States)

    2009-01-01

    As a part of NASA's active research of the Earth s atmosphere, which has included missions such as the Atmospheric Laboratory of Applications and Science (ATLAS, launched in 1992) and the Total Ozone Mapping Spectrometer (TOMS, launched on the Earth Probe satellite in 1996), the Agency also performs ground-based air pollution research. The ability to measure trace amounts of airborne pollutants precisely and quickly is important for determining natural patterns and human effects on global warming and air pollution, but until recent advances in field-grade spectroscopic instrumentation, this rapid, accurate data collection was limited and extremely difficult. In order to understand causes of climate change and airborne pollution, NASA has supported the development of compact, low power, rapid response instruments operating in the mid-infrared "molecular fingerprint" portion of the electromagnetic spectrum. These instruments, which measure atmospheric trace gases and airborne particles, can be deployed in mobile laboratories - customized ground vehicles, typically - to map distributions of pollutants in real time. The instruments must be rugged enough to operate rapidly and accurately, despite frequent jostling that can misalign, damage, or disconnect sensitive components. By measuring quickly while moving through an environment, a mobile laboratory can correlate data and geographic points, revealing patterns in the environment s pollutants. Rapid pollutant measurements also enable direct determination of pollutant sources and sinks (mechanisms that remove greenhouse gases and pollutants), providing information critical to understanding and managing atmospheric greenhouse gas and air pollutant concentrations.

  3. Analytical investigation of the atmospheric radiation limits in semigray atmospheres in radiative equilibrium

    OpenAIRE

    Pujol i Sagaró, Toni; North, Gerald R.

    2003-01-01

    We model the wavelength-dependent absorption of atmospheric gases by assuming constant mass absorption coefficients in finite-width spectral bands. Such a semigray atmosphere is analytically solved by a discrete ordinate method. The general solution is analyzed for a water vapor saturated atmosphere that also contains a carbon dioxide-like absorbing gas in the infrared. A multiple stable equilibrium with a relative upper limit in the outgoing long-wave radiation is found. Differing from previ...

  4. Measurement of gamma radiation around base station

    International Nuclear Information System (INIS)

    The ? -radiation have been measured around base station in Isparta region of Turkey to see the contribution of base station on the background radiation. Isparta which is surrounded by high mountain of Davras is located at southern part of Turkey. There are several volcanic activity in this region. The background radiation arises from two main sources. These are natural and technological sources. The natural radiation are mainly contributed by cosmic rays and terrestrial radiation. Cosmic rays comes from outside of the atmosphere after supernova explosion in the universe. The radiation comes direct from outside of atmosphere called primer cosmic rays and some of them can create seconder particle such as neutron.proton etc after some reaction with the oxygen, nitrogen etc in the atmosphere. The origin of terrestrial radiation are some radionucleus in rocks and soils. These are mainly 40K, 238U, 232Th and their products. The terrestrial radiation depends on geological structure of the region. The other types of γ-radiation is technological origin. With the development of technology in many different fields radiation can be produced. Nowadays mobile phones are widely used technological device and this requires base station to be established around habitable area. The electromagnetic radiations from base station and its effect are always a big question in people's mind and this would be investigated. The measurement have been performed using ASP/2e counter connected to a sing NaI(Tl) γ-ray detector. It was done around five different base station and also different altitude in Davraz mountain. The radiation dose from ambient air over five months ranges from 50 to 140 nGy h-1. The contribution of base station to the natural background radiation was clearly seen in the measurement

  5. Instrumentation for atmospheric ion measurements

    CERN Document Server

    Aplin, K L

    2005-01-01

    Small ions are part of the atmospheric aerosol spectrum, and study of ion-aerosol interactions is fundamental in atmospheric physics. Air ion physics and instrumentation are reviewed, including the historical context. A miniaturised Gerdien condenser for ion measurement, operating in situ to minimise inlet errors, is described. Two operating modes using independent current and voltage decay measurements are employed. A more sophisticated self-calibrating and fully programmable ion mobility spectrometer (PIMS) based on the same principles, is also discussed. Detailed analysis of error terms and application of new technology is demonstrated to greatly improve its capability. Self-consistent experimental approaches, including ionisation and ion concentration instruments, are used for calibration. In developing and characterising the individual components of the PIMS, favourable and unfavourable operating regimes are identified: this approach can also be applied to other aspiration ion counting techniques. Use of...

  6. The atmospheric implications of radiation belt remediation

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2006-08-01

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

  7. Electrochemical Measurement of Atmospheric Corrosion

    Science.gov (United States)

    DeArmond, Anna H.; Davis, Dennis D.; Beeson, Harold D.

    1999-01-01

    Corrosion of Shuttle thruster components in atmospheres containing high concentrations of nitrogen tetroxide (NTO) and water is an important issue in ground operations of bipropellant systems in humid locations. Measurements of the corrosivities of NTO-containing atmospheres and the responses of different materials to these atmospheres have been accomplished using an electrochemical sensor. The sensor is composed of alternating aluminum/titanium strips separated by thin insulating layers. Under high humidity conditions a thin film of water covers the surface of the sensor. Added NTO vapor reacts with the water film to form a conductive medium and establishes a galvanic cell. The current from this cell can be integrated with respect to time and related to the corrosion activity. The surface layer formed from humid air/NTO reacts in the same way as an aqueous solution of nitric acid. Nitric acid is generally considered an important agent in NTO corrosion situations. The aluminum/titanium sensor is unresponsive to dry air, responds slightly to humid air (> 75% RH), and responds strongly to the combination of humid air and NTO. The sensor response is a power function (n = 2) of the NTO concentration. The sensor does not respond to NTO in dry air. The response of other materials in this type of sensor is related to position of the material in a galvanic series in aqueous nitric acid. The concept and operation of this electrochemical corrosion measurement is being applied to other corrosive atmospheric contaminants such as hydrogen chloride, hydrogen fluoride, sulfur dioxide, and acidic aerosols.

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

    Science.gov (United States)

    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.

  9. Remote Sensing and In-Situ Observations of Arctic Mixed-Phase and Cirrus Clouds Acquired During Mixed-Phase Arctic Cloud Experiment: Atmospheric Radiation Measurement Uninhabited Aerospace Vehicle Participation

    International Nuclear Information System (INIS)

    The Atmospheric Radiation Monitor (ARM) uninhabited aerospace vehicle (UAV) program aims to develop measurement techniques and instruments suitable for a new class of high altitude, long endurance UAVs while supporting the climate community with valuable data sets. Using the Scaled Composites Proteus aircraft, ARM UAV participated in Mixed-Phase Arctic Cloud Experiment (M-PACE), obtaining unique data to help understand the interaction of clouds with solar and infrared radiation. Many measurements obtained using the Proteus were coincident with in-situ observations made by the UND Citation. Data from M-PACE are needed to understand interactions between clouds, the atmosphere and ocean in the Arctic, critical interactions given large-scale models suggest enhanced warming compared to lower latitudes is occurring

  10. Simple device measures solar radiation

    Science.gov (United States)

    Humphries, W. R.

    1977-01-01

    Simple inexpensive thermometer, insolated from surroundings by transparent glass or plastic encasement, measures intensities of solar radiation, or radiation from other sources such as furnaces or ovens. Unit can be further modified to accomplish readings from remote locations.

  11. Measurement and detection of radiation

    CERN Document Server

    Tsoulfanidis, Nicholas

    2015-01-01

    This fourth edition reflects recent major developments that have occurred in radiation detector materials, systems, and applications. It continues to provide the most practical and up-to-date introduction to radiation detector technology, proper measurement techniques, and analysis of results for engineers and scientists using radiation sources. New chapters emphasize the expanded use of radiation detection systems in nuclear non-proliferation, homeland security, and nuclear medicine. The book also discusses the correct ways to perform measurements following current health physics procedures.

  12. Radiation protection, measurements and methods

    International Nuclear Information System (INIS)

    The introductory lectures discuss subjects such as radiation protection principles and appropriate measuring techniques; methods, quantities and units in radiation protection measurement; technical equipment; national and international radiation protection standards. The papers presented at the various sessions deal with: Dosimetry of external radiation (27 papers); Working environment monitoring and emission monitoring (21 contributions); Environmental monitoring (19 papers); Incorporation monitoring (9 papers); Detection limits (4 papers); Non-ionizing radiation, measurement of body dose and biological dosimetry (10 papers). All 94 contributions (lectures, compacts and posters) are retrievable as separate records. (HP)

  13. Total tritium measurement in atmosphere

    International Nuclear Information System (INIS)

    Measurement of tritium in the atmosphere is of strong interest wherever this radionuclide is used. Therefore, a method is proposed for the joint measurement of burnable tritium, independently from its physico-chemical form, and of tritiated water. The method consists of transforming the tritiated molecules of the gases present in the air volume into tritiated water by burning them together with a known quantity of hydrogen. The water vapor is condensed and added to a liquid scintillator. The scintillator is also able to dissolve conventional filters so that the tritium attached to particulate and concentrated on these filters can be jointly measured, as will be discussed in a future report. The overall detection limit of the method is approximately 64 Bq m-3 for a combustion period of 10 min (which corresponds to sampling an air volume of 15 L) and a counting period of 10 min. This limit, much lower than the derived air concentrations in the most unfavorable cases, allows the application of the method for safety purposes. Moreover, the method can be integrated into a general procedure for the measurement of tritium in different chemical forms, to be applied in case of necessity

  14. MSL-RAD radiation environment measurements.

    Science.gov (United States)

    Guo, Jingnan; Zeitlin, Cary; Wimmer-Schweingruber, Robert F; Hassler, Donald M; Ehresmann, Bent; Köhler, Jan; Böhm, Eckart; Böttcher, Stephan; Brinza, David; Burmeister, Sönke; Cucinotta, Francis; Martin, Cesar; Posner, Arik; Rafkin, Scot; Reitz, Guenther

    2015-09-01

    In this study, results are presented from the on-board radiation assessment detector (RAD) of Mars Science Laboratory (MSL). RAD is designed to measure the energetic particle radiation environment, which consists of galactic cosmic rays (GCRs) and solar energetic particles (SEPs) as well as secondary particles created by nuclear interactions of primary particles in the shielding (during cruise) or Martian soil and atmosphere (surface measurements). During the cruise, RAD collected data on space radiation from inside the craft, thus allowing for a reasonable estimation of what a human crew travelling to/from Mars might be exposed to. On the surface of Mars, RAD is shielded by the atmosphere (from above) and the planet itself (from below). RAD measures the first detailed radiation data from the surface of another planet, and they are highly relevant for planning future crewed missions. The results for radiation dose and dose equivalent (a quantity most directly related to human health risk) are presented during the cruise phase, as well as on the Martian surface. Dose and dose equivalent are dominated by the continuous GCR radiation, but several SEP events were also detected and are discussed here. PMID:25969529

  15. Radar range measurements in the atmosphere.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2013-02-01

    The earths atmosphere affects the velocity of propagation of microwave signals. This imparts a range error to radar range measurements that assume the typical simplistic model for propagation velocity. This range error is a function of atmospheric constituents, such as water vapor, as well as the geometry of the radar data collection, notably altitude and range. Models are presented for calculating atmospheric effects on radar range measurements, and compared against more elaborate atmospheric models.

  16. Thick Galactic Cosmic Radiation Shielding Using Atmospheric Data

    Science.gov (United States)

    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.

  17. Radiative transfer through terrestrial atmosphere and ocean: Software package SCIATRAN

    International Nuclear Information System (INIS)

    tool for a wide range of remote sensing applications. Here, we present some selected comparisons of SCIATRAN simulations to published benchmark results, independent radiative transfer models, and various measurements from satellite, ground-based, and ship instruments. Methods for solving inverse problems related to remote sensing of the Earth's atmosphere using the SCIATRAN software are outside the scope of this study and will be discussed in a follow-up paper. The SCIATRAN software package along with a detailed User's Guide is freely available for non-commercial use via the webpage of the Institute of Environmental Physics (IUP), University of Bremen: (http://www.iup.physik.uni-bremen.de/sciatran). -- Highlights: • The description of the numerical aspects of the vectorial radiative transfer equation solution. • The application of the software for the simulation of radiative transfer in ocean. • The description of bidirectional distribution reflectance function models. • The full description of aerosol, cloud, and trace gases databases used in the framework of SCIATRAN. • The detailed description of applications of SCIATRAN for atmospheric optics

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

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Z.; Stamnes, K.; Weeks, W.F. [Univ. of Alaska, Fairbanks, AK (United States); Tsay, S.C. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    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.

  19. Solar and infrared radiation measurements

    CERN Document Server

    Vignola, Frank; Michalsky, Joseph

    2012-01-01

    The rather specialized field of solar and infrared radiation measurement has become more and more important in the face of growing demands by the renewable energy and climate change research communities for data that are more accurate and have increased temporal and spatial resolution. Updating decades of acquired knowledge in the field, Solar and Infrared Radiation Measurements details the strengths and weaknesses of instruments used to conduct such solar and infrared radiation measurements. Topics covered include: Radiometer design and performance Equipment calibration, installation, operati

  20. Ground truth data for test sites (SL-3). [solar radiation and thermal radiation brightness temperature measurements

    Science.gov (United States)

    1974-01-01

    Field measurements performed simultaneously with Skylab overpasses in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. The solar radiation region from 400 to 1300 nanometers and the thermal radiation region from 8 to 14 micrometer region were investigated. The measurements of direct solar radiation were analyzed for atmospheric optical depth; the total and reflected solar radiation were analyzed for target reflectivity. These analyses were used in conjunction with a radiative transfer computer program in order to calculate the amount and spectral distribution of solar radiation at the apertures of the EREP sensors. The instrumentation and techniques employed, calibrations and analyses performed, and results obtained are discussed.

  1. Measurement and detection of radiation

    CERN Document Server

    Tsoulfanidis, Nicholas

    2011-01-01

    This is an update of the standard textbook for the field of radiation measurement. It includes illustrative examples and new problems. The research and applications of nuclear instrumentation have grown substantially since publication of the previous editions. With the miniaturization of equipment, increased speed of electronic components, and more sophisticated software, radiation detection systems are now more productively used in many disciplines, including nuclear nonproliferation, homeland security, and nuclear medicine. Continuing in the tradition of its bestselling predecessors, "Measurement and Detection of Radiation, Third Edition" illustrates the fundamentals of nuclear interactions and radiation detection with a multitude of examples and problems. It offers a clearly written, accessible introduction to nuclear instrumentation concepts. The following are new to the third edition: a new chapter on the latest applications of radiation detection, covering nuclear medicine, dosimetry, health physics, no...

  2. Atmospheric transmittance model for photosynthetically active radiation

    Energy Technology Data Exchange (ETDEWEB)

    Paulescu, Marius; Stefu, Nicoleta; Gravila, Paul; Paulescu, Eugenia; Boata, Remus; Pacurar, Angel; Mares, Oana [Physics Department, West University of Timisoara, V Parvan 4, 300223 Timisoara (Romania); Pop, Nicolina [Department of Physical Foundations of Engineering, Politehnica University of Timisoara, V Parvan 2, 300223 Timisoara (Romania); Calinoiu, Delia [Mechanical Engineering Faculty, Politehnica University of Timisoara, Mihai Viteazu 1, 300222 Timisoara (Romania)

    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.

  3. An Analytic Radiative-Convective Model for Planetary Atmospheres

    CERN Document Server

    Robinson, Tyler D; 10.1088/0004-637X/757/1/104

    2012-01-01

    We present an analytic 1-D 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 sunli...

  4. Atmospheric trace gas measurements in the tropics

    OpenAIRE

    Petersen, Anna Katinka

    2009-01-01

    Fourier Transform Infrared (FTIR) spectrometry has been used for ground-based solar absorption, laboratory and flux measurements, to study the atmospheric composition, as well as physical and chemical processes in the atmosphere.The solar absorption FTIR measurements have been performed in Paramaribo, Suriname (5.8 N, 55.2 W) between September 2004 and November 2007 and represent the first remote sensing measurements in the inner tropics over severalyears. These measurements are of great impo...

  5. History of one family of atmospheric radiative transfer codes

    Science.gov (United States)

    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.

  6. Radiation measurements and quality control

    International Nuclear Information System (INIS)

    Accurate measurements are essential to research leading to a successful radiation process and to the commissioning of the process and the facility. On the other hand, once the process is in production, the importance to quality control of measuring radiation quantities (i.e., absorbed dose, dose rate, dose distribution) rather than various other parameters of the process (i.e. conveyor speed, dwell time, radiation field characteristics, product dimensions) is not clearly established. When the safety of the product is determined by the magnitude of the administered dose, as in radiation sterilization, waste control, or food preservation, accuracy and precision of the measurement of the effective dose are vital. Since physical dose measurements are usually simpler, more reliable and reproducible than biological testing of the product, there is a trend toward using standardized dosimetry for quality control of some processes. In many industrial products, however, such as vulcanized rubber, textiles, plastics, coatings, films, wire and cable, the effective dose can be controlled satisfactorily by controlling process variables or by product testing itself. In the measurement of radiation dose profiles by dosimetry, it is necessary to have suitable dose meter calibrations, to account for sources of error and imprecision, and to use correct statistical procedures in specifying dwell times or conveyor speeds and source and product parameters to achieve minimum and maximum doses within specifications. (author)

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

    Science.gov (United States)

    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

  8. The Great Plains low-level jet (LLJ) during the atmospheric radiation measurement (ARM) intensive observation period (IOP)-4 and simulations of land use pattern effect on the LLJ

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.; Raman, S. [North Carolina State Univ., Raleigh, NC (United States)

    1996-04-01

    The Great Plains low-level jet (LLJ) is an important element of the low-level atmospheric circulation. It transports water vapor from the Gulf of Mexico, which in turn affects the development of weather over the Great Plains of the central United States. The LLJ is generally recognized as a complex response of the atmospheric boundary layer to the diurnal cycle of thermal forcing. Early studies have attributed the Great Plains LLJ to the diurnal oscillations of frictional effect, buoyancy over sloping terrain, and the blocking effects of the Rocky Mountains. Recent investigations show that the speed of the LLJ is also affected by the soil type and soil moisture. Some studies also suggest that synoptic patterns may play an important role in the development of the LLJ. Land surface heterogeneties significantly affect mesoscale circulations by generating strong contrasts in surface thermal fluxes. Thus one would expect that the land use pattern should have effects on the LLJ`s development and structure. In this study, we try to determine the relative roles of the synoptic forcing, planetary boundary layers (PBL) processes, and the land use pattern in the formation of the LLJ using the observations from the Atmospheric Radiation Measurement (ARM) Intensive Operation Period (IOP)-4 and numerical sensitivity tests.

  9. Measurement of radiative neutralino production

    CERN Document Server

    Bartels, Christoph; Langenfeld, Ulrich; List, Jenny

    2012-01-01

    We perform the first experimental study with full detector simulation for the radiative production of neutralinos at the linear collider, at sqrt{s} = 500 GeV and realistic beam polarizations. We consider all relevant backgrounds, like the Standard Model background from radiative neutrino production. The longitudinal polarized beams enhance the signal and simultaneously reduce the background, such that statistical errors are significantly reduced. We find that the photon spectrum from the signal process can be well isolated. The neutralino mass and the cross section can be measured at a few per-cent level, with the largest systematic uncertainties from the measurement of the beam polarization and the beam energy spectrum.

  10. Radiation measurements and quality control

    International Nuclear Information System (INIS)

    The association between radiation measurements and quality control is established for radiation sterilization of medical products and food irradiation. Good quality control implies accurate radiation dosimetry and a discussion of the factors which can affect the accuracy of in-plant dosimetry is presented. It is argued that if systematic errors are to be avoided in in-plant dosimetry the plant operators will have to spend more time and effort in developing the skills associated with the accurate use of radiation dosemeter systems. The aims and merits of an international intercomparison programme recently set up by the IAEA are discussed. The benefits of accurate in-plant dosimetry for the operator, approving authority and purchaser are balanced against the extra dosimetric efforts required for good quality control. (author)

  11. Diffuse Sky Radiation in a Dry Turbid Atmosphere

    OpenAIRE

    R. A. Gupta; B. K. Agarwal

    1984-01-01

    Development of a simple method for the assessment of atmospheric turbidity all over the country in all seasons has been attempted. We have been able to derive a reasonably reliable equation relating diffuse sky radiation Dr on a horizontal surface to air mass mr and Angstrom Schuepp turbidity coefficient B, in a dry atmosphere with constant albedo (A = 0.25) of the terrain.

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

    Science.gov (United States)

    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.

  13. Upper Atmosphere Humidity Measurement with Drycap Sensor

    OpenAIRE

    Lehtola, Terhi Johanna

    2014-01-01

    Atmospheric water vapor is a significant greenhouse gas. To gain proper understanding of the impact of water vapor on the climate, atmospheric water vapor profiles should be measured with high precision and accuracy. Due to challenging environmental conditions including extremely low temperatures and humidity concentrations, few research grade instruments are capable of measuring humidity accurately in upper troposphere and stratosphere. Laborious utilization or inadequate resolution of the e...

  14. High-resolution terahertz atmospheric water vapor continuum measurements

    Science.gov (United States)

    Slocum, David M.; Goyette, Thomas M.; Giles, Robert H.

    2014-05-01

    The terahertz frequency regime is often used as the `chemical fingerprint' region of the electromagnetic spectrum due to the large number of rotational and vibrational transitions of many molecules of interest. This region of the spectrum has particular utility for applications such as pollution monitoring and the detection of energetic chemicals using remote sensing over long path lengths through the atmosphere. Although there has been much attention to atmospheric effects over narrow frequency windows, accurate measurements across a wide spectrum are lacking. The water vapor continuum absorption is an excess absorption that is unaccounted for in resonant line spectrum simulations. Currently a semiempirical model is employed to account for this absorption, however more measurements are necessary to properly describe the continuum absorption in this region. Fourier Transform Spectroscopy measurements from previous work are enhanced with high-resolution broadband measurements in the atmospheric transmission window at 1.5THz. The transmission of broadband terahertz radiation through pure water vapor as well as air with varying relative humidity levels was recorded for multiple path lengths. The pure water vapor measurements provide accurate determination of the line broadening parameters and experimental measurements of the transition strengths of the lines in the frequency region. Also these measurements coupled with the atmospheric air measurements allow the water vapor continuum absorption to be independently identified at 1.5THz. Simulations from an atmospheric absorption model using parameters from the HITRAN database are compared with the current and previous experimental results.

  15. Computational study of atmospheric transfer radiation on an equatorial tropical desert (La Tatacoa, Colombia)

    CERN Document Server

    Delgado-Correal, Camilo; Castaño, Gabriel

    2012-01-01

    Radiative transfer models explain and predict interaction between solar radiation and the different elements present in the atmosphere, which are responsible for energy attenuation. In Colombia there have been neither measurements nor studies of atmospheric components such as gases and aerosols that can cause turbidity and pollution. Therefore satellite images cannot be corrected radiometrically in a proper way. When a suitable atmospheric correction is carried out, loss of information is avoided, which may be useful for discriminating image land cover. In this work a computational model was used to find radiative atmospheric attenuation (300 1000nm wavelength region) on an equatorial tropical desert (La Tatacoa, Colombia) in order to conduct an adequate atmospheric correction.

  16. Solar Atmospheric Magnetic Energy Coupling: Radiative Redistribution Efficiency

    Science.gov (United States)

    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.

  17. Radiation Measurements aboard Spacelab 1

    Science.gov (United States)

    Benton, E. V.; Almasi, J.; Cassou, R.; Frank, A.; Henke, R. P.; Rowe, V.; Parnell, T. A.; Schopper, E.

    1984-07-01

    The radiation environment inside Spacelab 1 was measured by a set of passive radiation detectors distributed throughout the volume inside the module, in the access tunnel, and outside on the pallet. Measurements of the low-LET (linear energy transfer) component obtained from the thermoluminescence detectors ranged from 102 to 190 millirads, yielding an average low-LET dose rate of 11.2 millirads per day inside the module, about twice the low-LET dose rate measured on previous flights of the space shuttle. Because of the higher inclination of the orbit (57 degrees versus 28.5 degrees for previous shuttle flights), substantial fluxes of highly ionizing HZE particles (high charge and energy galactic cosmic rays) were observed, yielding an overall average mission dose-equivalent of about 150 millirems, more than three times higher that measured on previous shuttle missions.

  18. 1-D Radiative-Convective Model for Terrestrial Exoplanet Atmospheres

    Science.gov (United States)

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

    2016-10-01

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

  19. On the radiative equilibrium of irradiated planetary atmospheres

    CERN Document Server

    Guillot, Tristan

    2010-01-01

    The evolution of stars and planets is mostly controlled by the properties of their atmosphere. This is particularly true in the case of exoplanets close to their stars, for which one has to account both for an (often intense) irradiation flux, and from an intrinsic flux responsible for the progressive loss of the inner planetary heat. The goals of the present work are to help understanding the coupling between radiative transfer and advection in exoplanetary atmospheres and to provide constraints on the temperatures of the deep atmospheres. This is crucial in assessing whether modifying assumed opacity sources and/or heat transport may explain the inflated sizes of a significant number of giant exoplanets found so far. I use a simple analytical approach inspired by Eddington's approximation for stellar atmospheres to derive a relation between temperature and optical depth valid for plane-parallel static grey atmospheres which are both transporting an intrinsic heat flux and receiving an outer radiation flux. ...

  20. International radiation commissions 1896 to 2008. Research into atmospheric radiation from IMO to IAMAS

    Energy Technology Data Exchange (ETDEWEB)

    Bolle, H.J. (comp.); Moeller, F.; London, J.

    2008-05-15

    The document covers a historical compilation on research into atmospheric radiation from 1896 to 2008. The first part is a brief history of the radiation commissions of IMO (International Meteorological Organization) and IUGG (International Union of Geodesy and Geophysics) for the period 1824 to 1948. Part 2 Covers the International Radiation Commission (IRC) of IAM (International Association of Meteorology)/IAMAS (International Association of Meteorology and Atmospheric Sciences)/IAMAP (International Association of Meteorology and Atmospheric Physics); the Re-constitution of the IUGG Radiation Commision, the Officers of the International Radiation Commission of IUUG 1948-2008, and the activities of the Radiation Commision of the IUGG 1948-2008. The appendices include the Radiation Commission Members, the summaries of presented papers from 1954 and 1957, the IRC publications, and acronyms.

  1. International radiation commissions 1896 to 2008. Research into atmospheric radiation from IMO to IAMAS

    International Nuclear Information System (INIS)

    The document covers a historical compilation on research into atmospheric radiation from 1896 to 2008. The first part is a brief history of the radiation commissions of IMO (International Meteorological Organization) and IUGG (International Union of Geodesy and Geophysics) for the period 1824 to 1948. Part 2 Covers the International Radiation Commission (IRC) of IAM (International Association of Meteorology)/IAMAS (International Association of Meteorology and Atmospheric Sciences)/IAMAP (International Association of Meteorology and Atmospheric Physics); the Re-constitution of the IUGG Radiation Commision, the Officers of the International Radiation Commission of IUUG 1948-2008, and the activities of the Radiation Commision of the IUGG 1948-2008. The appendices include the Radiation Commission Members, the summaries of presented papers from 1954 and 1957, the IRC publications, and acronyms

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

    Science.gov (United States)

    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.

  3. Ground truth data for test sites (SL-4). [thermal radiation brightness temperature and solar radiation measurments

    Science.gov (United States)

    1974-01-01

    Field measurements performed simultaneous with Skylab overpass in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. Wavelength region covered include: solar radiation (400 to 1300 nanometer), and thermal radiation (8 to 14 micrometer). Measurements consisted of general conditions and near surface meteorology, atmospheric temperature and humidity vs altitude, the thermal brightness temperature, total and diffuse solar radiation, direct solar radiation (subsequently analyzed for optical depth/transmittance), and target reflectivity/radiance. The particular instruments used are discussed along with analyses performed. Detailed instrument operation, calibrations, techniques, and errors are given.

  4. Indirect determination of single scattering albedo and complex refractive index of atmospheric aerosol from combined spectral sun- and sky-radiance- as well spectral radiation flux-measurements and determination of radiative forcing. Final report; Indirekte Bestimmung der Single Scattering Albedo und des komplexen Brechungsindex des atmosphaerischen Aerosols aus kombinierten spektralen Sonnen- und Himmelsstrahlungs- sowie spektralen Strahlungsflussmessungen und Ermittlung des Strahlungsantriebs. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hoyningen-Huene, W. von; Burrows, J.P.; Schmidt, T.; Freitag, M.; Waltersdorf, M.; Roth, S.

    2001-07-01

    The insufficient knowledge of radiation parameters of the atmospheric aerosol yields a highly insufficient evaluation of the aerosol impact in different tasks. Climate research (determination of radiative forcing by aerosols), environmental control and monitoring (determination of aerosol impact), satellite remote sensing (atmospheric correction) and aerosol research (radiative properties) require the exact knowledge and complete data sets of optical aerosol parameters. During the closure experiment LACE-98 the main radiative aerosol parameters have been derived experimentally by closure of different atmospheric radiation measurements: spectral aerosol optical thickness, phase function and single scattering albedo. The use of spectral down-welling flux measurements enables the determination of spectral single scattering albedo. Radiative transfer calculations with these parameters have been used for the determination of the top-of-atmosphere radiance to be compared with satellite data (SeaWiFS). Resulting from these comparisons a dynamical surface reflectance model for land surfaces has been derived used in a retrieval procedure for the determination of the aerosol optical thickness from top-of-atmosphere reflectance from multi-spectral satellite data, applicable over land surface. The optical aerosol parameters, the retrieval procedure developed and the obtained regional distribution of the aerosol optical thickness over Germany are presented. (orig.) [German] Die unzureichende Kenntnis von strahlungsrelevanten Aerosolparametern fuehrt zu hohen Unsicherheiten bei der Bewertung des Aerosoleinflusses in verschiedenen Aufgabenbereichen. Klimaforschung (Bestimmung des Strahlungsantriebs durch Aerosole), Umweltkontrolle und Ueberwachung (Bestimmung des Aerosolimpakts), Fernerkundung (Atmosphaerenkorrektur) und Aerosolforschung (Strahlungseigenschaften) benoetigten exakte Kenntnis und komplette Saetze von optischen Aerosolparametern. Durch Schliessung verschiedener

  5. Absolute density measurements in the middle atmosphere

    Directory of Open Access Journals (Sweden)

    M. Rapp

    Full Text Available In the last ten years a total of 25 sounding rockets employing ionization gauges have been launched at high latitudes ( ~ 70° N to measure total atmospheric density and its small scale fluctuations in an altitude range between 70 and 110 km. While the determination of small scale fluctuations is unambiguous, the total density analysis has been complicated in the past by aerodynamical disturbances leading to densities inside the sensor which are enhanced compared to atmospheric values. Here, we present the results of both Monte Carlo simulations and wind tunnel measurements to quantify this aerodynamical effect. The comparison of the resulting ‘ram-factor’ profiles with empirically determined density ratios of ionization gauge measurements and falling sphere measurements provides excellent agreement. This demonstrates both the need, but also the possibility, to correct aerodynamical influences on measurements from sounding rockets. We have determined a total of 20 density profiles of the mesosphere-lower-thermosphere (MLT region. Grouping these profiles according to season, a listing of mean density profiles is included in the paper. A comparison with density profiles taken from the reference atmospheres CIRA86 and MSIS90 results in differences of up to 40%. This reflects that current reference atmospheres are a significant potential error source for the determination of mixing ratios of, for example, trace gas constituents in the MLT region.

    Key words. Middle atmosphere (composition and chemistry; pressure, density, and temperature; instruments and techniques

  6. Intercomparison of Shortwave Radiative Transfer Codes and Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Halthore, Rangasayi N.; Crisp, David; Schwartz, Stephen E.; Anderson, Gail; Berk, A.; Bonnel, B.; Boucher, Olivier; Chang, Fu-Lung; Chou, Ming-Dah; Clothiaux, Eugene E.; Dubuisson, P.; Fomin, Boris; Fouquart, Y.; Freidenreich, S.; Gautier, Catherine; Kato, Seiji; Laszlo, Istvan; Li, Zhanqing; Mather, Jim H.; Plana-Fattori, Artemio; Ramaswamy, V.; Ricchiazzi, P.; Shiren, Y.; Trishchenko, A.; Wiscombe, Warren J.

    2005-06-03

    Computation of components of shortwave (SW) or solar irradiance in the surface-atmospheric system forms the basis of intercomparison between 16 radiative transfer models of varying spectral resolution ranging from line-by-line models to broadband and general circulation models. In order of increasing complexity the components are: direct solar irradiance at the surface, diffuse irradiance at the surface, diffuse upward flux at the surface, and diffuse upward flux at the top of the atmosphere. These components allow computation of the atmospheric absorptance. Four cases are considered from pure molecular atmospheres to atmospheres with aerosols and atmosphere with a simple uniform cloud. The molecular and aerosol cases allow comparison of aerosol forcing calculation among models. A cloud-free case with measured atmospheric and aerosol properties and measured shortwave radiation components provides an absolute basis for evaluating the models. For the aerosol-free and cloud-free dry atmospheres, models agree to within 1% (root mean square deviation as a percentage of mean) in broadband direct solar irradiance at surface; the agreement is relatively poor at 5% for a humid atmosphere. A comparison of atmospheric absorptance, computed from components of SW radiation, shows that agreement among models is understandably much worse at 3% and 10% for dry and humid atmospheres, respectively. Inclusion of aerosols generally makes the agreement among models worse than when no aerosols are present, with some exceptions. Modeled diffuse surface irradiance is higher than measurements for all models for the same model inputs. Inclusion of an optically thick low-cloud in a tropical atmosphere, a stringent test for multiple scattering calculations, produces, in general, better agreement among models for a low solar zenith angle (SZA = 30?) than for a high SZA (75?). All models show about a 30% increase in broadband absorptance for 30? SZA relative to the clear-sky case and almost no

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

    Science.gov (United States)

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

    2009-03-01

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

  8. A new thoron atmosphere reference measurement system.

    Science.gov (United States)

    Sabot, B; Pierre, S; Michielsen, N; Bondiguel, S; Cassette, P

    2016-03-01

    A new thoron reference ((220)Rn) in air measurement system is developed at the LNE-LNHB with the collaboration of the IRSN. This measurement system is based on a reference volume with an alpha detector which is able to directly measure thoron and its decay products at atmospheric pressure. In order to improve the spectrum quality of the thoron progenies, we have applied an electric field to catch the decay products on the detector surface. The developed system is a portative device which can be used to measure reference thoron atmosphere such as the BACCARA chamber at IRSN (Picolo et al., 1999). As this system also allows the measurement of radon ((222)Rn) in air, it was validated using the radon primary standards made at the LNE-LNHB. This thoron measurement system will be used, at IRSN, as a reference instrument in order to calibrate the thoron activity concentration in the BACCARA facility. PMID:26701661

  9. Diffuse Sky Radiation in a Dry Turbid Atmosphere

    Directory of Open Access Journals (Sweden)

    R. A. Gupta

    1984-07-01

    Full Text Available Development of a simple method for the assessment of atmospheric turbidity all over the country in all seasons has been attempted. We have been able to derive a reasonably reliable equation relating diffuse sky radiation Dr on a horizontal surface to air mass mr and Angstrom Schuepp turbidity coefficient B, in a dry atmosphere with constant albedo (A = 0.25 of the terrain.

  10. FMCW Radar Performance for Atmospheric Measurements

    Directory of Open Access Journals (Sweden)

    T. Ince

    2010-04-01

    Full Text Available Frequency-modulated continuous-wave radars (FMCW have been used in the investigation of the atmosphere since the late 1960’s. FMCW radars provide tremendous sensitivity and spatial resolution compared to their pulsed counterparts and are therefore attractive for clear-air remote-sensing applications. However, these systems have some disadvantages and performance limitations that have prevented their widespread use by the atmospheric science community. In this study, system performance of atmospheric FMCW radar is analyzed and some measurement limitations for atmospheric targets are discussed. The effects of Doppler velocities and spectral widths on radar performance, radar’s near-field operation, and parallax errors for two-antenna radar systems are considered. Experimental data collected by the highresolution atmospheric FMCW radar is used to illustrate typical performance qualitatively based on morphological backscattered power information. A post-processing based on single-lag covariance differences between the Bragg and Rayleigh echo is applied to estimate clear-air component from refractive index turbulence and perform quantitative analysis of FMCW radar reflectivity from atmospheric targets.

  11. Equipment for measuring radiation. Part 3. Technique of measuring radiation

    Energy Technology Data Exchange (ETDEWEB)

    Radwanowski, L.J.

    1979-01-01

    Difficulties are noted in measuring the effects of radiation because of the excessively low energy of the measured fields. In nature there are different magnetic-dynamic and magnetic-hydrodynamic generators which are sources of very low intensity which changes in time. The equipment of measurements is examined in the example of one of the generators, underground water current. The apparatus is described in detail for measuring the intensity of the electromagnetic SHF field. Under the underground water currents a change is observed in the intensity of the electromagnetic field. The possibilities are also examined of direct measurement of ultrasonic elastic fluctuations caused by the underground current, as well as the possibility of recording other physical fields (spontaneous polarization, soil temperature). A study was made of the effect of the underground water current on the occurrence of physical, chemical and biological processes: photochemical reactions, reactions of metal oxidation, Golomb effect (change in the rate of sedimentation of argillaceous particles in water under the influence of a biofield), change in air humidity and soil water content, change in intensity of the magnetic field, Hall effect, change in luminescence of certain organisms or the luminophore released by them. Basic plans are presented of certain measurement and recording devices.

  12. First measurements of the Martian radiation environment

    International Nuclear Information System (INIS)

    The 2001 Mars Odyssey spacecraft has been returning data from Mars since February 2002. Its orbit is polar and nearly circular, about 400 km above the surface, with a two-hour period. Among the instruments onboard Odyssey are the Martian Radiation Environment Experiment (MARIE) and the Gamma Ray Spectrometer (GRS), which is a suite of instruments that includes several neutron detectors. This paper focuses on results from MARIE, which is measuring Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE) at Mars in order to assess radiation health risks to future human explorers. MARIE is highly efficient for SPE, and for GCR in the charge range from 2 (helium) to 10 (neon); spectra obtained in this range are compared to data from the ACE/ CRIS detector and show good agreement. The SPE data obtained by MARIE are unique and may show effects due to 'magnetic anomalies,' regions of remanent magnetism on the Martian surface. Data from the Mars Global Surveyor magnetometer are used in this analysis. Although the GRS instruments are primarily intended to measure radiation from the Martian surface, both the gamma-ray detector and the neutron detectors provide valuable information about the local radiation environment at Mars. The gamma-ray crystal is useful in providing coverage during MARIE data outages, which arise due to limited storage space and tend to limit acquisition during SPE. The neutron detectors provide data that can, with modeling of neutron transport through the atmosphere, be used to predict surface neutron doses. The combined data from these instruments are giving a clear picture of the radiation environment at Mars and the potential risks that will be faced by humans who venture there

  13. Meso-Beta-Scale Data Assimilation of the Winter Icing and Storms Program/Atmospheric Radiation Measurement Program 91 intensive observing period case on 6 March 1991

    International Nuclear Information System (INIS)

    To support the ARM program, we have proposed to develop an Integrated Data Assimilation and Sounding System (IDASS). The IDASS is composed of a measurement component and a modeling component. The measurement component (Integrated Sounding System or ISS) is developed around a suite of in situ and active and passive remote sensors. Individually, these sensors satisfy certain needs, together they function in a synergistic and complementary mode. The modeling component is an enhanced nonhydrostatic version of the Penn State/NCAR mesoscale model with data assimilation capability. The goal of IDASS is to provide continuous high-resolution tropospheric profiles of basic meteorological variables by continuous assimilation of measurements taken by ISS. The objectives of this study are (1) to assess the impact of mesoscale data assimilation on the model results, and (2) to evaluate the basic concept of IDASS

  14. Accuracy of Lidar Measurements of the Atmosphere

    Science.gov (United States)

    Kavaya, M. J.; Menzies, R. T.

    1986-01-01

    Report reviews sources of systematic error in laser radar (lidar) measurements of particles in atmosphere. Report applies particularly to stationary pulsed carbon dioxide lidars of type used to measure backscatter from aerosols in troposphere. Provides information for calibrating such systems accurately and consistently and interpreting their data correctly. Also useful in calibrating mobile and airborne lidars, lidars operating at wavelengths other than those of carbon dioxide lasers, and continuouswave lidars.

  15. Alternative application for the radiation background in the development of the atlas database of atmospheric radiation

    CERN Document Server

    De la Hoz, Ivan Arturo Morales

    2014-01-01

    Nowadays radiation is one of the variables to be considered in the environmental forecasting and it is meaningful in the increase of global warming, together greenhouse effect. The radiation considered by the meteorological organizations depends on the World Radiometric Reference (WRR), the World Standard Group (WSG), addressed by the World Meteorological Organization (WMO). This work is based on the cosmic microwave background, as a variable to be estimated in order to get information about the incident radiation in the Earth's atmosphere, as a valuable and meaningful contribution in the building of the radiation atlas by the (UPME) and (IDEAM). Due to the fact that the variables considered are ultraviolet and infrared radiation, ozone column, direct radiation and diffuse radiation, the last two get the global radiation, and are the only ones to be evaluated by the national meteorological organizations in the country. The study of the cosmic background radiation as a research project will provide data which ...

  16. SUMER: Solar Ultraviolet Measurements of Emitted Radiation

    Science.gov (United States)

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

    1992-01-01

    The experiment Solar Ultraviolet Measurements of Emitted Radiation (SUMER) is designed for the investigations of plasma flow characteristics, turbulence and wave motions, plasma densities and temperatures, structures and events associated with solar magnetic activity in the chromosphere, the transition zone and the corona. Specifically, SUMER will measure profiles and intensities of Extreme Ultraviolet (EUV) lines emitted in the solar atmosphere ranging from the upper chromosphere to the lower corona; determine line broadenings, spectral positions and Doppler shifts with high accuracy, provide stigmatic images of selected areas of the Sun in the EUV with high spatial, temporal and spectral resolution and obtain full images of the Sun and the inner corona in selectable EUV lines, corresponding to a temperature from 10,000 to more than 1,800,000 K.

  17. Benchmark results in vector atmospheric radiative transfer

    International Nuclear Information System (INIS)

    In this paper seven vector radiative transfer codes are inter-compared for the case of underlying black surface. They include three techniques based on the discrete ordinate method (DOM), two Monte-Carlo methods, the successive orders scattering method, and a modified doubling-adding technique. It was found that all codes give very similar results. Therefore, we were able to produce benchmark results for the Stokes parameters both for reflected and transmitted light in the cases of molecular, aerosol and cloudy multiply scattering media. It was assumed that the single scattering albedo is equal to one. Benchmark results have been provided by several studies before, including Coulson et al., Garcia and Siewert, Wauben and Hovenier, and Natraj et al. among others. However, the case of the elongated phase functions such as for a cloud and with a high angular resolution is presented here for the first time. Also in difference with other studies, we make inter-comparisons using several codes for the same input dataset, which enables us to quantify the corresponding errors more accurately.

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

    Science.gov (United States)

    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.

  19. Soil-Vegetation-Atmosphere Radiative Transfer Model in Microwave Region

    Institute of Scientific and Technical Information of China (English)

    JIA Yuanyuan; LI Zhaoliang

    2008-01-01

    The radiative transfer is one of the significant theories that describe the processes of scattering,emission,and absorption of electromagnetic radiant intensity through scattering medium.It is the basis of the study on the quantitative remote sensing.In this paper,the radiative characteristics of soil,vegetation,and atmosphere were described respectively.The numerical solution of radiative transfer was accomplished by Successive Orders of Scattering (SOS).A radiative transfer model for simulating microwave brightness temperature over land surfaces was constructed,designed,and implemented.Analyzing the database generated from soil-vegetation-atmosphere radiative transfer model under Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) configuration showed that the atmospheric effects on microwave brightness temperature should not be neglected,particularly for higher frequency,and can be parameterized.At the same time,the relationship between the emissivities of the different channels was developed.The study results will promote the development of algorithm to retrieve geophysical parameters from microwave remotely sensed data.

  20. Isotope measurement techniques for atmospheric methane

    International Nuclear Information System (INIS)

    Measurement techniques for the carbon isotopic composition of atmospheric methane (δ13C) are described in detail as applied in several leading institutions active in this field since many years. The standard techniques with offline sample preparation and subsequent measurement by dual inlet isotope ratio mass spectrometry (IRMS) are compared with continuous flow IRMS. The potential use of infrared absorption spectroscopy is briefly discussed. Details on quality control and calibration are provided. Basic analytical aspects for the measurement of other species, 2H and 14C, are also given. (author)

  1. Brown carbon: a significant atmospheric absorber of solar radiation?

    Directory of Open Access Journals (Sweden)

    Y. Feng

    2013-09-01

    Full Text Available Several recent observational studies have shown organic carbon aerosols to be a significant source of absorption of solar radiation. The absorbing part of organic aerosols is referred to as "brown" carbon (BrC. Using a global chemical transport model and a radiative transfer model, we estimate for the first time the enhanced absorption of solar radiation due to BrC in a global model. The simulated wavelength dependence of aerosol absorption, as measured by the absorption Ångström exponent (AAE, increases from 0.9 for non-absorbing organic carbon to 1.2 (1.0 for strongly (moderately absorbing BrC. The calculated AAE for the strongly absorbing BrC agrees with AERONET spectral observations at 440–870 nm over most regions but overpredicts for the biomass burning-dominated South America and southern Africa, in which the inclusion of moderately absorbing BrC has better agreement. The resulting aerosol absorption optical depth increases by 18% (3% at 550 nm and 56% (38% at 380 nm for strongly (moderately absorbing BrC. The global simulations suggest that the strongly absorbing BrC contributes up to +0.25 W m−2 or 19% of the absorption by anthropogenic aerosols, while 72% is attributed to black carbon, and 9% is due to sulfate and non-absorbing organic aerosols coated on black carbon. Like black carbon, the absorption of BrC (moderately to strongly inserts a warming effect at the top of the atmosphere (TOA (0.04 to 0.11 W m−2, while the effect at the surface is a reduction (−0.06 to −0.14 W m−2. Inclusion of the strongly absorption of BrC in our model causes the direct radiative forcing (global mean of organic carbon aerosols at the TOA to change from cooling (−0.08 W m−2 to warming (+0.025 W m−2. Over source regions and above clouds, the absorption of BrC is higher and thus can play an important role in photochemistry and the hydrologic cycle.

  2. Evaluation of arctic broadband surface radiation measurements

    OpenAIRE

    Matsui, N.; C. N. Long; J. Augustine; Halliwell, D.; T. Uttal; Longenecker, D.; O. Nievergall; Wendell, J.; Albee, R.

    2011-01-01

    The Arctic is a challenging environment for making in-situ radiation measurements. A standard suite of radiation sensors is typically designed to measure the total, direct and diffuse components of incoming and outgoing broadband shortwave (SW) and broadband thermal infrared, or longwave (LW) radiation. Enhancements can include various sensors for measuring irradiance in various narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are...

  3. Evaluation of Arctic broadband surface radiation measurements

    OpenAIRE

    Matsui, N.; C. N. Long; J. Augustine; Halliwell, D.; T. Uttal; Longenecker, D.; Niebergall, O.; Wendell, J.; Albee, R.

    2012-01-01

    The Arctic is a challenging environment for making in-situ surface radiation measurements. A standard suite of radiation sensors is typically designed to measure incoming and outgoing shortwave (SW) and thermal infrared, or longwave (LW), radiation. Enhancements may include various sensors for measuring irradiance in narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that ...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  6. Changes in Atmospheric Constituents and in Radiative Forcing. Chapter 2

    International Nuclear Information System (INIS)

    This chapter updates information taken from Chapters 3 to 6 of the IPCC Working Group I Third Assessment Report. It concerns itself with trends in forcing agents and their precursors since 1750, and estimates their contribution to the radiative forcing (RF) of the climate system. Discussion of the understanding of atmospheric composition changes is limited to explaining the trends in forcing agents and their precursors. Areas where significant developments have occurred since the TAR are highlighted. The chapter draws on various assessments since the TAR, in particular the 2002 World Meteorological Organization (WMO), United Nations Environment Programme (UNEP) Scientific Assessment of Ozone Depletion (2003) and the IPCC Technology and Economic Assessment Panel (TEAP) special report on Safeguarding the Ozone Layer and the Global Climate System (2005). The chapter assesses anthropogenic greenhouse gas changes, aerosol changes and their impact on clouds, aviation-induced contrails and cirrus changes, surface albedo changes and natural solar and volcanic mechanisms. The chapter reassesses the 'radiative forcing' concept (Sections 2.2 and 2.8), presents spatial and temporal patterns of RF, and examines the radiative energy budget changes at the surface. For the long-lived greenhouse gases (carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluoro-carbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6), hereinafter collectively referred to as the LLGHGs; Section 2.3), the chapter makes use of new global measurement capabilities and combines long-term measurements from various networks to update trends through 2005. Compared to other RF agents, these trends are considerably better quantified; because of this, the chapter does not devote as much space to them as previous assessments (although the processes involved and the related budgets are further discussed in Sections 7.3 and 7

  7. Detection of atmospheric Cherenkov radiation using solar heliostat mirrors

    Science.gov (United States)

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

    1996-10-01

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

  8. ARTS, the atmospheric radiative transfer simulator, version 2

    International Nuclear Information System (INIS)

    The second version of the atmospheric radiative transfer simulator, ARTS, is introduced. This is a general software package for long wavelength radiative transfer simulations, with a focus on passive microwave observations. The core part provides a workspace environment, in line with script languages. New for this version is an agenda mechanism that gives a high degree of modularity. The framework is intended to be as general as possible: the polarisation state can be fully described, the model atmosphere can be one- (1D), two- (2D) or three-dimensional (3D), a full description of geoid and surface is possible, observation geometries from the ground, from satellite, and from aeroplane or balloon are handled, and surface reflection can be treated in simple or complex manners. Remote sensing applications are supported by a comprehensive and efficient treatment of sensor characteristics. Jacobians can be calculated for the most important atmospheric variables in non-scattering conditions. Finally, the most prominent feature is the rigorous treatment of scattering that has been implemented in two modules: a discrete ordinate iterative approach mainly used for 1D atmospheres, and a Monte Carlo approach which is the preferred algorithm for 3D atmospheres. ARTS is freely available, and maintained as an open-source project.

  9. SUMER: Solar Ultraviolet Measurements of Emitted Radiation

    Science.gov (United States)

    Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.; Grewing, M.; Huber, M. C. E.; Jordan, M. C. E.; Lemaire, P.; Marsch, E.; Poland, A. I.

    1988-01-01

    The SUMER (solar ultraviolet measurements of emitted radiation) experiment is described. It will study flows, turbulent motions, waves, temperatures and densities of the plasma in the upper atmosphere of the Sun. Structures and events associated with solar magnetic activity will be observed on various spatial and temporal scales. This will contribute to the understanding of coronal heating processes and the solar wind expansion. The instrument will take images of the Sun in EUV (extreme ultra violet) light with high resolution in space, wavelength and time. The spatial resolution and spectral resolving power of the instrument are described. Spectral shifts can be determined with subpixel accuracy. The wavelength range extends from 500 to 1600 angstroms. The integration time can be as short as one second. Line profiles, shifts and broadenings are studied. Ratios of temperature and density sensitive EUV emission lines are established.

  10. Measurements and correlations between several atmospheric parameters

    Directory of Open Access Journals (Sweden)

    Kolarž Predrag

    2008-01-01

    Full Text Available Diurnal atmospheric air-ion concentrations have been investigated at a site where synchronous aerosol, ozone, temperature and relative humidity measurements were also made. Air-ions, temperature and relative humidity were measured with Gerdien type Cylindrical Detector of Air-Ions (CDI-06 made in the Institute of Physics, Belgrade. Ozone and aerosols were measured with commercial instruments owned by the Institute of Public Health, Belgrade. Typical daily variations of the measured parameters were analyzed and showed that air-ions of both signs and ozone are positively correlated, while aerosols show strong inverse correlation with air-ions. Also, concentrations of air-ions and ozone are decreasing with temperature while aerosol concentration and humidity are increasing. These processes could be explained concerning properties of the specified parameters, measuring place properties and weather conditions.

  11. Detection of atmospheric Cherenkov radiation using solar heliostat mirrors

    CERN Document Server

    Ong, R A

    1996-01-01

    The gamma-ray energy region between 20 and 250 GeV is largely unexplored. Ground-based atmospheric Cherenkov detectors offer a possible way to explore this region, but large Cherenkov photon collection areas are needed to achieve low energy thresholds. This paper discusses the development of a Cherenkov detector using the heliostat mirrors of a solar power plant as the primary collector. As part of this development, we built a prototype detector consisting of four heliostat mirrors and used it to record atmospheric Cherenkov radiation produced in extensive air showers created by cosmic ray particles.

  12. Ambient radiation exposure: measurements and effects

    International Nuclear Information System (INIS)

    A brief review of the available literature, data and reports of various radiation exposure and protection studies and various measurements techniques are presented. A linear quadratic model has been given illustrating the validity of radiation hormesis

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

    Science.gov (United States)

    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

  14. Measurement of atmospheric neutrino oscillations with PINGU

    Energy Technology Data Exchange (ETDEWEB)

    Krings, Kai; Coenders, Stefan; Euler, Sebastian; Vehring, Markus; Wallraff, Marius; Wiebusch, Christopher [RWTH Aachen Univ. (Germany). III. Physikalisches Inst.; Collaboration: IceCube-Collaboration

    2013-07-01

    With IceCube's low-energy extension DeepCore it is possible to study atmospheric neutrino oscillations in the energy range between 10 GeV and 100 GeV. Current analyses are sensitive to the first minimum of the survival probability of atmospheric muon neutrinos at about 25 GeV for vertically upgoing neutrinos. For the 'Precision IceCube Next Generation Upgrade' (PINGU) it is planned to install additional strings with a denser spacing inside the DeepCore volume. By this, PINGU will lower the neutrino energy threshold to a few GeV. In this talk it is investigated how the accuracy of the measurement of the oscillation parameters θ{sub 23} and Δm{sub 32} can be improved by PINGU with respect to DeepCore.

  15. Atmospheric Measurements by the 2002 Geoscience Laser Altimeter System Mission

    Science.gov (United States)

    Spinhirne, James D.; Starr, David OC. (Technical Monitor)

    2002-01-01

    The NASA Earth Observing System (EOS) program is a multiple platform NASA initiative for the study of global change. As part of the EOS project, the Geoscience Laser Altimeter System (GLAS) was selected as a laser sensor filling complementary requirements for several earth science disciplines including atmospheric and surface applications. Late in 2002, the GaAs instrument is to be launched for a three to five year observational mission. For the atmosphere, the instrument is designed to full fill comprehensive requirements for profiling of radiatively significant cloud and aerosol. Algorithms have been developed to process the cloud and aerosol data and provide standard data products. After launch there will be a three-month project to analyze and understand the system performance and accuracy of the data products. As an EOS mission, the GaAs measurements and data products will be openly available to all investigators. An overview of the instrument, data products and evaluation plan is given.

  16. Environmental radiation measurement in CTBT verification system

    International Nuclear Information System (INIS)

    well as the development of the automatic analyzing system of gamma-ray spectrum data and the atmospheric diffusion backtracking software, both of which are necessary for the NDC 2. Technologies, data, and samples obtained through the CTBT activities are supposed to be provided for the interest of the signatory nations. Equally high-quality measurement data and filter samples from the stations around the world offer opportunities, on a global scale, for detecting radionuclide dispersion, monitoring radiation levels and studying natural radioactivity, as well as supporting atmospheric studies, biological research and environmental change tracking. (author)

  17. Measurements of atmospheric carbon dioxide concentration above the ocean

    Energy Technology Data Exchange (ETDEWEB)

    Voskresenskii, A.I.; Kamenogradskii, N.E.

    1984-01-01

    Changes in the composition of the atmosphere can have a destabilizing effect on the climate. One change is related to an increase in the concentration of carbon dioxide as a result of the combustion of organic fuels. The most effective procedures for monitoring the atmospheric carbon dioxide concentration are discussed, taking into account suitable analytic methods and the most appropriate locations for the conduction of the measurements. It is found that polar and oceanic regions are best suited for the performance of the considered measurements. The analytic procedure selected is based on a spectroscopic approach utilizing the absorption of solar radiation by carbon dioxide at a wavelength of 2.06 microns. A description is given of measurements conducted on Soviet expeditions to the Antarctic during the time from 1979 to 1981. The concentration of atmospheric carbon dioxide as a function of geographic latitude is shown in graphs, taking into account data for January, February, March, and April. Water vapor concentrations are also shown. 11 references.

  18. Comparison of Arctic clouds between European Center for Medium-Range Weather Forecasts simulations and Atmospheric Radiation Measurement Climate Research Facility long-term observations at the North Slope of Alaska Barrow site

    Science.gov (United States)

    Zhao, Ming; Wang, Zhien

    2010-12-01

    This study evaluated the European Center for Medium-Range Weather Forecasts (ECMWF) model-simulated clouds and boundary layer (BL) properties based upon Atmospheric Radiation Measurement Climate Research Facility observations at the North Slope of Alaska site during 1999-2007. The ECMWF model-simulated near-surface humidity had seasonal dependent biases as large as 20%, while also experiencing difficulty representing BL temperature inversion height and strength during the transition seasons. Although the ECMWF model captured the seasonal variation of surface heat fluxes, it had sensible heat flux biases over 20 W m-2 in most of the cold months. Furthermore, even though the model captured the general seasonal variations of low-level cloud fraction (LCF) and liquid water path (LWP), it still overestimated the LCF by 20% or more and underestimated the LWP over 50% in the cold season. On average, the ECMWF model underestimated LWP by ˜30 g m-2 but more accurately predicted ice water path for BL clouds. For BL mixed-phase clouds, the model predicted water-ice mass partition was significantly lower than the observations, largely due to the temperature dependence of water-ice mass partition used in the model. The ECMWF model captured the general response of cloud fraction and LWP on large-scale vertical motion changes but overpredicted the magnitude of the difference, especially for LWP. The new cloud and BL schemes of the ECMWF model that were implemented after 2003 only resulted in minor improvements in BL cloud simulations in summer. These results indicate that significant improvements in cold season BL and mixed-phase cloud processes in the model are needed.

  19. A single-scattering approximation for infrared radiative transfer in limb geometry in the Martian atmosphere

    International Nuclear Information System (INIS)

    We present a single-scattering approximation for infrared radiative transfer in limb geometry in the Martian atmosphere. It is based on the assumption that the upwelling internal radiation field is dominated by a surface with a uniform brightness temperature. It allows the calculation of the scattering source function for individual aerosol types, mixtures of aerosol types, and mixtures of gas and aerosol. The approximation can be applied in a Curtis-Godson radiative transfer code and is used for operational retrievals from Mars Climate Sounder measurements. Radiance comparisons with a multiple scattering model show good agreement in the mid- and far-infrared although the approximate model tends to underestimate the radiances in realistic conditions of the Martian atmosphere. Relative radiance differences are found to be about 2% in the lowermost atmosphere, increasing to ∼10% in the middle atmosphere of Mars. The increasing differences with altitude are mostly due to the increasing contribution to limb radiance of scattering relative to emission at the colder, higher atmospheric levels. This effect becomes smaller toward longer wavelengths at typical Martian temperatures. The relative radiance differences are expected to produce systematic errors of similar magnitude in retrieved opacity profiles.

  20. A review of worldwide atmospheric mercury measurements

    Directory of Open Access Journals (Sweden)

    F. Sprovieri

    2010-09-01

    Full Text Available A large number of activities have been carried out to characterise the levels of mercury (Hg species in ambient air and precipitation, in order to understand how they vary over time and how they depend on meteorological conditions. Following the discovery of atmospheric Hg depletion events (AMDEs in Polar Regions, a significant research effort was made to assess the chemical-physical mechanisms behind the rapid conversion of atmospheric gaseous Hg (Hg0 into reactive and water-soluble forms which are potentially bioavailable. The understanding of the way in which Hg is released into the atmosphere, transformed, deposited and eventually incorporated into biota is of crucial importance not only for the polar regions but also for the marine environment in general. The oceans and seas are both sources and sinks of Hg and play a major role in the Hg cycle. In this work, the available Hg concentration datasets from a number of terrestrial sites (industrial, rural and remote in both the Northern and Southern Hemispheres as well as over oceans and seas have been investigated. The higher Hg species concentration and variability observed in the Northern Hemisphere suggest that the majority of emissions and re-emissions occur there. The inter-hemispherical gradient with higher total gaseous mercury (TGM concentrations in the Northern Hemisphere has remained nearly constant over the years for which data are available. The analysis of Hg concentration patterns indicates the differences in regional source/sink characteristics, with increasing variability toward areas strongly influenced by anthropogenic sources. The large increase in Hg emissions in rapidly developing countries (i.e., China, India over the last decade, due primarily to a sharp increase in energy production from coal combustion, are not currently reflected in the long-term measurements of TGM in ambient air and precipitation at continuous monitoring sites in either Northern Europe or

  1. Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation at Thessaloniki, Greece

    Directory of Open Access Journals (Sweden)

    A. V. Lindfors

    2013-04-01

    Full Text Available Pyranometer measurements of the solar surface radiation (SSR are available at many locations worldwide, often as long time series covering several decades into the past. These data constitute a potential source of information on the atmospheric aerosol load. Here, we present a method for estimating the aerosol optical depth (AOD using pyranometer measurements of the SSR together with total water vapor column information. The method, which is based on radiative transfer simulations, was developed and tested using recent data from Thessaloniki, Greece. The effective AOD calculated using this method was found to agree well with co-located AERONET measurements, exhibiting a correlation coefficient of 0.9 with 2/3 of the data found within ±20% or ±0.05 of the AERONET AOD. This is similar to the performance of current satellite aerosol methods. Differences in the AOD as compared to AERONET can be explained by variations in the aerosol properties of the atmosphere that are not accounted for in the idealized settings used in the radiative transfer simulations, such as variations in the single scattering albedo and Ångström exponent. Furthermore, the method is sensitive to calibration offsets between the radiative transfer simulations and the pyranometer SSR. The method provides an opportunity of extending our knowledge of the atmospheric aerosol load to locations and times not covered by dedicated aerosol measurements.

  2. Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation at Thessaloniki, Greece

    Directory of Open Access Journals (Sweden)

    A. V. Lindfors

    2012-12-01

    Full Text Available Pyranometer measurements of the solar surface radiation (SSR are available at many locations worldwide, often as long time series covering several decades into the past. These data constitute a potential source of information on the atmospheric aerosol load. Here, we present a method for estimating the aerosol optical depth (AOD using pyranometer measurements of the SSR together with total water vapor column information. The method, which is based on radiative transfer simulations, was developed and tested using recent data from Thessaloniki, Greece. The effective AOD calculated using this method was found to agree well with co-located AERONET measurements, exhibiting a correlation coefficient of 0.9 with 2/3 of the data found within ±20% or ±0.05 of the AERONET AOD. This is similar to the performance of current satellite aerosol methods. Differences in the AOD as compared to AERONET can be explained by variations in the aerosol properties of the atmosphere that are not accounted for in the idealized settings used in the radiative transfer simulations, such as variations in the single scattering albedo and Ångström exponent. Furthermore, the method is sensitive to calibration offsets between the radiative transfer simulations and the pyranometer SSR. The method provides an opportunity of extending our knowledge of the atmospheric aerosol load to locations and times not covered by dedicated aerosol measurements.

  3. Alexandrite laser source for atmospheric lidar measurements

    Science.gov (United States)

    Pelon, J.; Loth, C.; Flamant, P.; Megie, G.

    1986-01-01

    During the past years, there has been a marked increase in interest in the applications of vibronic solid state lasers to meteorology and atmospheric physics. Two airborne lidar programs are now under development in France. The differential absorption lidar (DIAL) method with vibronic solid state lasers is very attractive for water vapor, temperature and pressure measurements. Alexandrite laser and titanium-sapphire are both suitable for these applications. However, only alexandrite rods are commercially available. The requirements on the laser source for airborne dial applications are two fold: (1) a restriction on laser linewidth and a requirement on stability and tunability with a good spectral purity; and (2) a requirement on the time separation between the two pulses. These constraints are summarized.

  4. Next-generation angular distribution models for top-of-atmosphere radiative flux calculation from CERES instruments: methodology

    OpenAIRE

    W. Su; Corbett, J; Z. Eitzen; L. Liang

    2015-01-01

    The top-of-atmosphere (TOA) radiative fluxes are critical components to advancing our understanding of the Earth's radiative energy balance, radiative effects of clouds and aerosols, and climate feedback. The Clouds and the Earth's Radiant Energy System (CERES) instruments provide broadband shortwave and longwave radiance measurements. These radiances are converted to fluxes by using scene-type-dependent angular distribution models (ADMs). This paper describes the next-gener...

  5. Atmospheric effect on the ground-based measurements of broadband surface albedo

    OpenAIRE

    Manninen, T.; Riihelä, A.; De Leeuw, G.

    2012-01-01

    Ground-based pyranometer measurements of the (clear-sky) broadband surface albedo are affected by the atmospheric conditions (mainly by aerosol particles, water vapour and ozone). A new semi-empirical method for estimating the magnitude of the effect of atmospheric conditions on surface albedo measurements in clear-sky conditions is presented. Global and reflected radiation and/or aerosol optical depth (AOD) at two wavelengths are needed to apply the method. Depending on the...

  6. Radiative instabilities of atmospheric jets and boundary layers

    International Nuclear Information System (INIS)

    Complex flows occur in the atmosphere and they can be source of internal gravity waves. We focus here on the sources associated with radiative and shear (or Kelvin-Helmholtz) instabilities. Stability studies of shear layers in a stably stratified fluid concern mainly cases where shear and stratification are aligned along the same direction. In these cases, Miles (1961) and Howard (1961) found a necessary condition for stability based on the Richardson number: Ri ≥ 1/4. In this thesis, we show that this condition is not necessary when shear and stratification are not aligned: we demonstrate that a two-dimensional planar Bickley jet can be unstable for all Richardson numbers. Although the most unstable mode remains 2D, we show there exists an infinite family of 3D unstable modes exhibiting a radiative structure. A WKBJ theory is found to provide the main characteristics of these modes. We also study an inviscid and stratified boundary layer over an inclined wall with non-Boussinesq and compressible effects. We show that this flow is unstable as soon as the wall is not horizontal for all Froude numbers and that strongly stratified 3D perturbations behave exactly like compressible 2D perturbations. Applications of the results to the jet stream and the atmospheric boundary layer are proposed. (author)

  7. Measuring NIR Atmospheric Extinction Using a Global Positioning System Receiver

    CERN Document Server

    Blake, Cullen H

    2011-01-01

    Modeling molecular absorption by Earth's atmosphere is important for a wide range of astronomical observations, including broadband NIR photometry and high-resolution NIR spectroscopy. Using a line-by-line radiative transfer approach, we calculate theoretical transmission spectra in the deep red optical (700 to 1050 nm) for Apache Point Observatory. In this region the spectrum is dominated by H2O, which is known to be highly variable in concentration on short timescales. We fit our telluric models to high-resolution observations of A stars and estimate the relative optical depth of H2O absorption under a wide range of observing conditions. We compare these optical depth estimates to simultaneous measurements of Precipitable Water Vapor (PWV) based on data from a Global Positioning System (GPS) receiver located at Apache Point. We find that measured PWV correlates strongly with the scaling of H2O absorption lines in our spectra, indicating that GPS-based PWV measurements combined with atmospheric models may be...

  8. Long-path atmospheric measurements using dual frequency comb measurements

    Science.gov (United States)

    Waxman, Eleanor; Cossel, Kevin; Truong, Gar-Wing; Giorgetta, Fabrizio; Swann, William; Coddington, Ian; Newbury, Nathan

    2016-04-01

    The dual frequency comb spectrometer is a new tool for performing atmospheric trace gas measurements. This instrument is capable of measuring carbon dioxide, methane, and water with extremely high resolution in the region between 1.5 and 2.1 microns in the near-IR. It combines the high resolution of a laboratory-based FTIR instrument with the portability of a long-path DOAS system. We operate this instrument at path lengths of a few kilometers, thus bridging the spatial resolution of in-situ point sensors and the tens of square kilometer footprints of satellites. This spatial resolution is ideal for measuring greenhouse gas emissions from cities. Here we present initial long-path integrated column measurements of the greenhouse gases water, carbon dioxide, and methane in an urban environment. We present a time series with 5 minute time resolution over a 2 kilometer path in Boulder, Colorado at the urban-rural interface. We validate this data via a comparison with an in-situ greenhouse gas monitor co-located along the measurement path and show that we agree well on the baseline concentration but that we are significantly less sensitive to local point source emission that have high temporal variability, making this instrument ideal for measurements of average city-wide emissions. We additionally present progress towards measurements over an 11 kilometer path over downtown Boulder to measure the diurnal flux of greenhouse gases across the city.

  9. Measuring transient radiation effects in optical fibers

    International Nuclear Information System (INIS)

    We propose a new method for measuring transient radiation effects in optical fibers on a nanosecond timescale. The method, which incorporates a streak camera, allows more precise time resolution than other methods and has the advantage of measuring the radiation-induced attenuation as a function of wavelength and time simultaneously. By choosing different light sources and sweep speeds, radiation-induced attenuation may be measured under a variety of experimental configurations. Examples of the type of output obtained with our method are given

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

    International Nuclear Information System (INIS)

    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. -- Highlights: • Proof of existence of the radiance within the scope of the theory of atmospheric radiative transfer. • Proof of relations between the photon number and photon energy density function and the radiance. • Strictly mathematical derivation of the analytical properties of these state density functions

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

    Science.gov (United States)

    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.

  12. An analysis of the dependence of clear-sky top-of-atmosphere outgoing longwave radiation on atmospheric temperature and water vapor

    Science.gov (United States)

    Dessler, A. E.; Yang, P.; Lee, J.; Solbrig, J.; Zhang, Z.; Minschwaner, K.

    2008-09-01

    We have analyzed observations of clear-sky top-of-atmosphere outgoing longwave radiation (OLR) measured by the Clouds and the Earth's Radiant Energy System (CERES). These measurements were obtained during March 2005 at night and over the ocean and cover latitudes from 70°N to 70°S. First, we compare the OLR measurements to OLR calculated from two radiative transfer models. The models use as input simultaneous and collocated measurements of atmospheric temperature and atmospheric water vapor made by the Atmospheric Infrared Sounder (AIRS). We find excellent agreement between the models' predictions of OLR and observations, well within the uncertainty of the measurements. We also analyze the sensitivity of OLR to changing surface temperature Ts, atmospheric temperature Ta, and atmospheric water vapor q. We find that OLR is most sensitive to unit changes in Ta when that change occurs in the lower troposphere. For q, the altitude distribution of sensitivity varies between the midlatitudes, subtropics, and the convective region. We also partition the observed variations in OLR into contributions from changing Ts, Ta, and q. In the midlatitudes, changes in Ts and Ta contribute approximately equally, and are partially offset by changes in q. In the subtropics, changes in Ta dominate, with a smaller contribution from changes in Ts and a relatively small offsetting contribution from q. In the tropical convective region, a rapid increase in q in the midtroposphere leads to a dramatic reduction in OLR with increasing Ts, which has been termed the "super greenhouse effect".

  13. Longwave atmospheric radiation as a possible indicator of the aviation impact

    Energy Technology Data Exchange (ETDEWEB)

    Zaitseva, N.A. [Central Aerological Observatory of the Russian Federal Service for Hydrometeorology and Environmental Monitoring, Moscow (Russian Federation)

    1997-12-31

    Aircraft emissions changing composition of the atmospheric air should be sensed by radiation parameters, such as downward (in first turn) and upward long-wave fluxes. It might be supposed that the accurate measurements of long-wave (LW) radiation fluxes in regions of crowded aircraft routes time outside these regions, could detect the influence. Main transformation of the long-wave radiation (LWR) proceeds in the troposphere which absorbs and irradiates the LWR. The only mass method of the LWR measurements in the free atmosphere became the radiometer probe. In the former USSR it was successfully developed in 1961, and since 1963 the special radiometer sounding network started to make regular observations over the USSR territory. Rather small spatial variations of the downward LWR flux was observed indicating rather high homogeneity of the atmosphere composition. Analysis of the seasonal variations of the downward LWR has revealed that over some stations it has the opposite course of changes from summer to winter and it is mainly observed at rather high levels. (R.P.) 10 refs.

  14. TEPC measurements in different radiation fields

    International Nuclear Information System (INIS)

    Some experimental results of measurements using tissue-equivalent proportional counters are given. Spectra of neutrons with different energies, gamma radiation and protons were measured. The LET spectra which constitute the test results can be used for gaining a better physical understanding and interpretation of the effects that mixed neutron-gamma radiation field would exert in the tissue. The LET spectra are also used to calibrate the detector for a wider range of particles and energies. ( M.D.)

  15. Web based Measurement System for Solar Radiation

    OpenAIRE

    Shachi Awasthi; Dr. P. Mor

    2012-01-01

    We present in this paper, the principles of the measurement system for solar radiation, and our implementation using Web based data logging concept. The photocurrent produced by Silicon PN junction is used as a solar radiation transducer, to make it more viable we have used commercially available solar panels as our transducers. Using a silicon solar cell as sensor, a low cost solar radiometer can be constructed. The photocurrent produced by solar cell is electronically tailored to be measure...

  16. Phantoms for Radiation Measurements of Mobile Phones

    DEFF Research Database (Denmark)

    Pedersen, Gert Frølund

    2001-01-01

    Measurements of radiation efficiency for a handheld phone equipped with a patch and a helical antenna operated near the human user have been performed. Both measurements include a simple head plus hand phantom and live persons are considered. The position of the hand on the phone is found...... to be the main reason for the large variation in radiation efficiency among persons. The tilt angle of the phone and the distance between the head and phone only play a minor role...

  17. Magellan radio occultation measurements of atmospheric waves on Venus

    Science.gov (United States)

    Hinson, David P.; Jenkins, J. M.

    1995-01-01

    Radio occultation experiments were conducted at Venus on three consecutive orbits of the Magellan spacecraft in October 1991. Each occultation occurred over the same topography (67 deg N, 127 deg E) and at the same local time (22 hr 5 min), but the data are sensitive to zonal variations because the atmosphere rotates significantly during one orbit. Through comparisons between observations and predictions of standard wave theory, we have demonstrated that small-scale oscillations in retrieved temperature profiles as well as scintillations in received signal intensity are caused by a spectrum of vertically propagating internal gravity waves. There is a strong similarity between the intensity scintillations observed here and previous measurements, which pertain to a wide range of locations and experiment dates. This implies that the same basic phenomenon underlies all the observations and hence that gravity waves are a persistent, global feature of Venus' atmosphere. We obtained a fairly complete characterization of a gravity wave that appears above the middle cloud in temperature measurements on all three orbits. The amplitude and vertical wavelength are about 4 K and 2.5 km respectively, at 65 km. A model for radiative damping implies that the wave intrinsic frequency is approximately 2 x 10(exp 4) rad/sec, the corresponding ratio between horizontal and vertical wavelengths is approximately 100. The wave is nearly stationary relative to the surface or the Sun. Radiative attenuation limits the wave amplitude at altitudes above approximately 65 km, leading to wave drag on the mean zonal winds of about +0.4 m/sec per day (eastward). The sign, magnitude, and location of this forcing suggest a possible role in explaining the decrease with height in the zonal wind speed that is believed to occur above the cloud tops. Temperature oscillations with larger vertical wavelengths (5-10 km) were also observed on all three orbits, but we are able unable to interpret these

  18. Airborne Measurements of Atmospheric Methane Using Pulsed Laser Transmitters

    Science.gov (United States)

    Numata, Kenji; Riris, Haris; Wu, Stewart; Gonzalez, Brayler; Rodriguez, Michael; Hasselbrack, William; Fahey, Molly; Yu, Anthony; Stephen, Mark; Mao, Jianping; Kawa, Stephan

    2016-01-01

    Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. At NASA Goddard Space Flight Center (GSFC) we have been developing a laser-based technology needed to remotely measure CH4 from orbit. We report on our development effort for the methane lidar, especially on our laser transmitters and recent airborne demonstration. Our lidar transmitter is based on an optical parametric process to generate near infrared laser radiation at 1651 nanometers, coincident with a CH4 absorption. In an airborne flight campaign in the fall of 2015, we tested two kinds of laser transmitters --- an optical parametric amplifier (OPA) and an optical parametric oscillator (OPO). The output wavelength of the lasers was rapidly tuned over the CH4 absorption by tuning the seed laser to sample the CH4 absorption line at several wavelengths. This approach uses the same Integrated Path Differential Absorption (IPDA) technique we have used for our CO2 lidar for ASCENDS. The two laser transmitters were successfully operated in the NASAs DC-8 aircraft, measuring methane from 3 to 13 kilometers with high precision.

  19. Ionizing radiation in industrial measurements

    International Nuclear Information System (INIS)

    The development of instruments for industrial measurements have been extensively reviewed. Especially the measuring systems for control and automation as well as industrial radiometric gages have been presented and their application in Poland and other countries have been shown. The future developing trends in the interesting branch has been discussed

  20. Exposure of Finnish population to ultraviolet radiation and radiation measurements

    International Nuclear Information System (INIS)

    This report is based on a survey of the literature on radiation risks involved in sunbathing and the use of solaria. The purpose of the report is to provide background information for the development of regulations on solaria and for informing the public about the risks posed by solaria and the sun. The report gives an overview of the properties and biological effects of ultraviolet radiation. The most important regulations and recommendations issued in various countries are presented. The connection between ultraviolet radiation and the risks of skin cancer is examined both on a general level and in reference to information obtained from the Finnish Cancer Registry. In Finland, the incidence of melanomas nearly tripled between 1960 and 1980. The most important cause is considered to be the population's increased exposure to the su's ultraviolet radiation. There are no reliable data on the connection between the use of solaria and the risks of skin cancer. It is estimated, however, that solaria account for less than 10 per cent of the skin cancer risk of the whole population. There are some difficult physical problems associated with the measurement of ultraviolet radiation emitted by both natural sources and solaria. A preliminary study of these problems has been undertaken by means of a survey of the available literature, supplemented by a review of measurements performed by the Finnish Centre For Radiation and Nuclear Safety. The estimated inaccuracy of the Optronic 742 spectroradiometer used by the Centre in the measurement of ultraviolet radiation emitted by the sun and solaria is about +-14%

  1. Radiation doses from Hanford site releases to the atmosphere

    International Nuclear Information System (INIS)

    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

  2. Hydraulic effects in a radiative atmosphere with ionization

    CERN Document Server

    Bhat, Pallavi

    2014-01-01

    In a paper of 1978, Eugene Parker postulated the need for hydraulic downward motion to explain magnetic flux concentrations at the solar surface. A similar process has recently also been seen in simplified (e.g., isothermal) models of flux concentrations from the negative effective magnetic pressure instability. We study the effects of partial ionization near the radiative surface on the formation of such magnetic flux concentrations. We first obtain one-dimensional (1D) equilibrium solutions using either a Kramers-like opacity or the ${\\rm H}^{-}$ opacity. The resulting atmospheres are then used as initial conditions in two-dimensional (2D) models where flows are driven by an imposed gradient force resembling a localized negative pressure in the form of a blob. To isolate the effects of partial ionization and radiation, we ignore turbulence and convection. In 1D models, due to partial ionization, an unstable stratification forms always near the surface. We show that the extrema in the specific entropy profil...

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

    Science.gov (United States)

    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.

  4. Coordinated weather balloon solar radiation measurements during a solar eclipse

    Science.gov (United States)

    2016-01-01

    Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550757

  5. Coordinated weather balloon solar radiation measurements during a solar eclipse.

    Science.gov (United States)

    Harrison, R G; Marlton, G J; Williams, P D; Nicoll, K A

    2016-09-28

    Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. PMID:27550757

  6. All terrain robot for remote radiation measurement

    International Nuclear Information System (INIS)

    In view of recent nuclear accidents like that in Fukushima Daiichi, the necessity for remote radiation measurement, as a first step in crisis management has been felt in the nuclear technology community. Also, some regular maintenance works in nuclear facilities result in substantial radiation exposure to human workers. All these have provided an impetus to the development of an All-Terrain Robot capable of remote radiation mapping inside nuclear installations; accordingly a prototype system has been developed at DRHR, Bhabha Atomic Research Centre. This robot has been designed to negotiate uneven terrain including staircases. Also, the robot is equipped with three onboard cameras and a retractable radiation detector and it is remotely controlled over wireless communication links with a computer. The control software, through its seamless interface, allows for easy viewing and logging of radiation data in real time. The system has been deployed and field trials have been taken

  7. The Monte Carlo atmospheric radiative transfer model McArtim: Introduction and validation of Jacobians and 3D features

    International Nuclear Information System (INIS)

    A new Monte Carlo atmospheric radiative transfer model is presented which is designed to support the interpretation of UV/vis/near-IR spectroscopic measurements of scattered Sun light in the atmosphere. The integro differential equation describing the underlying transport process and its formal solution are discussed. A stochastic approach to solve the differential equation, the Monte Carlo method, is deduced and its application to the formal solution is demonstrated. It is shown how model photon trajectories of the resulting ray tracing algorithm are used to estimate functionals of the radiation field such as radiances, actinic fluxes and light path integrals. In addition, Jacobians of the former quantities with respect to optical parameters of the atmosphere are analyzed. Model output quantities are validated against measurements, by self-consistency tests and through inter comparisons with other radiative transfer models.

  8. Statistical characteristics of atmospheric aerosol as determined from AERONET measurements

    Science.gov (United States)

    Yoon, Jongmin; Kokhanovsky, Alexander

    2015-04-01

    Seasonal means and standard deviations of column-integrated aerosol optical properties (e.g. spectral aerosol optical thickness (AOT), single scattering albedo, phase function, Ångström exponent, volume particle size distribution, complex refractive index, absorbing aerosol optical thickness) from several Aerosol Robotic Network (AERONET) sites located in typical aerosol source and background regions are investigated (Holben et al., 1998). The AERONET program is an inclusive network of ground-based sun-photometers that measure atmospheric aerosol optical properties (http://aeronet.gsfc.nasa.gov/). The results can be used for improving the accuracy of satellite-retrieved AOT, assessments of the global aerosol models, studies of atmospheric pollution and aerosol radiative forcing on climate. We have paid a special attention to several AERONET sites that are Mexico_City (Mexico), Alta_Floresta (Brazil), Avignon (France), Solar_Village (Saudi Arabia), and Midway_Island (Pacific) representative for industrial/urban, biomass burning, rural, desert dust and oceanic aerosols, respectively. We have found that the optical and microphysical aerosol properties are highly dependent on the local aerosol emission sources and seasonal meteorological conditions.

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

    Science.gov (United States)

    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

  10. Radiation protection measurement. Philosophy and implementation

    International Nuclear Information System (INIS)

    A selection from the proceedings of the International Symposium held by the U.K. Society for radiological protection in June 1974 was presented. The central theme was the philosophy of radiation protection measurement and its interpretation although some specific areas of good health physics practice were included. The 28 papers selected were chosen to be either representative of the central theme or of wider interest. The papers have been grouped in 6 main sections: philosophy of measurements; interpretation of measurements; implementation by legislation and monitoring; radiation exposure and control; reactor safety and siting; accidents

  11. Measurement of $\\psip$ Radiative Decays

    CERN Document Server

    Ablikim, M; Ban, Y; Cai, X; Chen, H F; Chen, H S; Chen, H X; Chen, J C; Chen Jin; Chen, Y B; Chu, Y P; Dai, Y S; Diao, L Y; Deng, Z Y; Dong, Q F; Du, S X; Fang, J; Fang, S S; Fu, C D; Gao, C S; Gao, Y N; Gu, S D; Gu, Y T; Guo, Y N; Guo, Z J; Harris, F A; He, K L; He, M; Heng, Y K; Hou, J; Hu, H M; Hu, J H; Hu, T; Huang, X T; Ji, X B; Jiang, X S; Jiang, X Y; Jiao, J B; Jin, D P; Jin, S; Lai, Y F; Li, G; Li, H B; Li, J; Li, R Y; Li, S M; Li, W D; Li, W G; Li, X L; Li, X N; Li, X Q; Liang, Y F; Liao, H B; Liu, B J; Liu, C X; Liu, F; Fang Liu; Liu, H H; Liu, H M; Liu, J; Liu, J B; Liu, J P; Jian Liu; Liu, Q; Liu, R G; Liu, Z A; Lou, Y C; Lu, F; Lu, G R; Lu, J G; Lundborg, A; Luo, C L; Ma, F C; Ma, H L; Ma, L L; Ma, Q M; Mao, Z P; Mo, X H; Nie, J; Olsen, S L; Ping, R G; Qi, N D; Qin, H; Qiu, J F; Ren, Z Y; Rong, G; Ruan, X D; Shan, L Y; Shang, L; Shen, C P; Shen, D L; Shen, X Y; Sheng, H Y; Sun, H S; Sun, S S; Sun, Y Z; Sun, Z J; Tang, X; Tong, G L; Varner, G S; Wang, D Y; Wang, L; Wang, L L; Wang, L S; Wang, M; Wang, P; Wang, P L; Wang, Y F; Wang, Z; Wang, Z Y; Wang, Zheng; Wiedner, U; Wei, C L; Wei, D H; Weng, Y; Wu, N; Xia, X M; Xie, X X; Xu, G F; Xu, X P; Xu, Y; Yan, M L; Yang, H X; Yang, Y X; Ye, M H; Ye, Y X; Yu, G W; Yuan, C Z; Yuan, Y; Zang, S L; Zeng, Y; Zhang, B X; Zhang, B Y; Zhang, C C; Zhang, D H; Zhang, H Q; Zhang, H Y; Zhang, J W; Zhang, J Y; Zhang, S H; Zhang, X Y; Zhang, Yiyun; Zhang, Z X; Zhang, Z P; Zhao, D X; Zhao, J W; Zhao, M G; Zhao, P P; Zhao, W R; Zhao, Z G; Zheng, H Q; Zheng, J P; Zheng, Z P; Zhou, L; Zhu, K J; Zhu, Q M; Zhu, Y C; Zhu, Y S; Zhu, Z A; Zhuang, B A; Zhuang, X A; Zou, B S; al., et

    2006-01-01

    Using 14 million psi(2S) events accumulated at the BESII detector, we report first measurements of branching fractions or upper limits for psi(2S) decays into gamma ppbar, gamma 2(pi^+pi^-), gamma K_s K^-pi^++c.c., gamma K^+ K^- pi^+pi^-, gamma K^{*0} K^- pi^+ +c.c., gamma K^{*0}\\bar K^{*0}, gamma pi^+pi^- p pbar, gamma 2(K^+K^-), gamma 3(pi^+pi^-), and gamma 2(pi^+pi^-)K^+K^- with the invariant mass of hadrons below 2.9GeV/c^2. We also report branching fractions of psi(2S) decays into 2(pi^+pi^-) pi^0, omega pi^+pi^-, omega f_2(1270), b_1^\\pm pi^\\mp, and pi^0 2(pi^+pi^-) K^+K^-.

  12. Radio Occultation Measurements of Pluto's Atmosphere with New Horizons

    Science.gov (United States)

    Hinson, David P.; Linscott, Ivan; Young, Leslie; Stern, S. Alan; Bird, Mike; Ennico, Kimberly; Gladstone, Randy; Olkin, Catherine B.; Pätzold, Martin; Strobel, Darrell F.; Summers, Michael; Tyler, G. Leonard; Weaver, Harold A.; Woods, Will; New Horizons Science Team

    2016-10-01

    The reconnaissance of the Pluto System by New Horizons in July 2015 included a radio occultation at Pluto. The observation was performed with signals transmitted simultaneously by four antennas of the NASA Deep Space Network, two at the Goldstone complex in California and two at the Canberra complex in Australia. Each antenna radiated 20 kW without modulation at a wavelength of 4.17 cm. New Horizons received the four signals with its 2.1-m high-gain antenna, where the signals were split into pairs and processed independently by two identical REX radio science instruments. Each REX relied on a different ultra-stable oscillator as its frequency reference. The signals were digitized and filtered, and the data samples were stored on the spacecraft for later transmission to Earth. Six months elapsed before all data had arrived on the ground, and the results reported here are the first to utilize the complete set of observations. Pluto's tenuous atmosphere is a significant challenge for radio occultation sounding, which led us to develop a specialized method of analysis. We began by calibrating each signal to remove effects not associated with Pluto's atmosphere, including the diffraction pattern from Pluto's surface. We reduced the noise and increased our sensitivity to the atmosphere by averaging the results from the four signals, while using other combinations of the signals to characterize the noise. We then retrieved profiles of number density, pressure, and temperature from the averaged phase profiles at both occultation entry and exit. Finally, we used a combination of analytical methods and Monte Carlo simulations to determine the accuracy of the measurements. The REX profiles provide the first direct measure of the surface pressure and temperature structure in Pluto's lower atmosphere. There are significant differences between the structure at entry (193.5°E, 17.0°S, sunset) and exit (15.7°E, 15.1°N, sunrise), which arise from spatial variations in surface

  13. Uncertainities in carbon dioxide radiative forcing in atmospheric general circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Cess, R.D.; Zhang, M.H. (State Univ. of New York, Stony Brook, NY (United States)); Potter, G.L.; Gates, W.L.; Taylor, K.E. (Lawrence Livermore National Laboratory, CA (United States)); Colman, R.A.; Fraser, J.R.; McAvaney, B.J. (Bureau of Meterorology Research Centre, Victoria (Australia)); Dazlich, D.A.; Randall, D.A. (Colorado State Univ., Fort Collins, CO (United States)); Del Genio, A.D.; Lacis, A.A. (Goddard Institute for Space Studies, New York, NY (United States)); Esch, M.; Roeckner, E. (Max Planck Institute for Meteorology, Hamburg (Germany)); Galin, V. (Russian Academy of Sciences, Moscow (Russian Federation)); Hack, J.J.; Kiehl, J.T. (National Center for Atmospheric Research, Boulder, CO (United States)); Ingram, W.J. (Hadley Centre for Climate Prediction and Research, Berkshire (United Kingdom)); Le Treut, H.; Lli, Z.X. (Laboratoire de Meteorologie Dynamique, Paris (France)); Liang, X.Z.; Wang, W.C. (State Univ. of New York, Albany, NY (United States)); Mahfouf,

    1993-11-19

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

  14. Recent measurements of coherent transition radiation

    International Nuclear Information System (INIS)

    An extended series of experiments has been used to investigate transition radiation in the x-ray spectral region. The x-rays were generated at the Lawrence Livermore National Laboratory electron-positron linear accelerator by 54 MeV electrons traversing multiple thin-foil targets. The measured angular and spectral distributions have shown excellent agreement with calculated predictions based on a simplified theoretical description of transition radiation. Recently, energy-resolved measurements of x-ray generation by targets consisting of multiple closely-spaced foils has clearly demonstrated the longitudinal coherence of transition radiation. This behavior might lead to a variety of applications such as tuneable narrow-band x-ray sources, measurement of x-ray dielectric constants, or particle beam diagnostics. These issues will be discussed, and recent results will be presented

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

    Science.gov (United States)

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

    2006-11-01

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

  16. Development of radiation protection and measurement technology

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Si Young; Lee, T. Y.; Kim, J. L.; Kim, B. H.; Lee, B. J.; Chung, K. K.; Lee, K. C.; Chung, R. I.; Han, Y. D.; Kim, J. S.; Lee, H. S.; Kim, C. K.; Yoon, K. S.; Jeong, D. Y.; Yoon, S. C.; Yoon, Y. C.; Lee, S. Y.; Kim, J. S.; Seo, K. W. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Kim, J. K.; Lee, J. K. [Hanyang Univ., Seoul (Korea, Republic of)

    1997-07-01

    Reference X-, gamma, beta and neutron radiation fields complying with the ISO and ANSI standards have been established and evaluated to provide a basic technical support in national radiation protection dosimetry program and to provide calibration measurement devices. Personal dose evaluation algorithm has been developed with these reference radiation fields, which comply well with both domestic and the new ANSI N13.11, to evaluate accurate personal dose equivalents. A personal internal dosimetry algorithm which can estimate the intakes of radionuclides from the results of in vivo bioassay and the resulting internal doses has been developed and verified its performance. It was also evaluated to be equality excellent compared with those being used in foreign countries and used to make a computer code for internal dose evaluation which can be run with PC under the Windows environment. A BOMAB phantom for precise calibration of in vivo system has been also designed, fabricated and test-evaluated. Based on the ALARA concept of the optimization principle of radiation protection, a method for estimating the cost for radiation protection has been studied and an objective monetary cost of detriment due to radiation exposure, called {alpha} value ($/man-Sv) has been derived and proposed based on the Korean socio-economic situation and human risk factors to provide basic data for the radiation protection optimization study in Korea. (author). 100 refs., 104 tabs., 69 figs.

  17. Hydraulic effects in a radiative atmosphere with ionization

    Science.gov (United States)

    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.

  18. On the magnetic field signal radiated by an atmospheric pressure room temperature plasma jet

    International Nuclear Information System (INIS)

    In this paper, the magnetic field signal radiated from an atmospheric pressure room temperature plasma plume is measured. It's found that the magnetic field signal has similar waveform as the current carried by the plasma plume. By calibration of the magnetic field signal, the plasma plume current is obtained by measuring the magnetic field signal radiated by the plasma plume. In addition, it is found that, when gas flow modes changes from laminar regime to turbulence regime, the magnetic field signal waveforms appears different, it changes from a smooth curve to a curve with multiple spikes. Furthermore, it is confirmed that the plasma plume generated by a single electrode (without ground electrode) plasma jet device carries higher current than that with ground electrode.

  19. Direct measurements of nitric oxide height distribution in the middle atmosphere

    International Nuclear Information System (INIS)

    The [NO] distribution over the entire range of middle atmosphere altitudes (∼20-100 km) has been obtained in only one experiment involving measurement of solar radiation absorption in the infrared range; the measurements were performed aboard the orbital station Spacelab-1. This study presents results of the first direct rock measurements of the height distribution of nitric oxide in the range ∼30-90 km, performed by an RFI photoionization sensor

  20. Gamma radiation background measurements from Spacelab 2

    Science.gov (United States)

    Paciesas, William S.; Gregory, John C.; Fishman, Gerald J.

    1989-01-01

    A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

  1. Measurement of Radiated Power Loss on EAST

    Institute of Scientific and Technical Information of China (English)

    段艳敏; 王亮; 胡立群; 毛松涛; 许平; 陈开云; 林士耀; 钟国强; 张继宗; 张凌

    2011-01-01

    A type of silicon detector known as AXUV (absolute extreme ultraviolet) photodiodes is successfully used to measure the radiated power in EAST. The detector is characterized by compact structure, fast temporal response (〈0.5 s) and flat spectral sensitivity in the range from ultra-violet to X-ray. Two 16-channel AXUV arrays are installed in EAST to view the whole poloidal cross-section of plasma. Based on the diagnostic system, typical radiation distributions for both limiter and divertor plasma are obtained and compared. As divertor detachment occurs, the radiation distribution in X-point region is observed to vary distinctly. The total radiation power losses in discharges with different plasma parameters are briefly analyzed.

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

    Science.gov (United States)

    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.

  3. Volume 1 Chapter 2: Emissions and concentrations of radiatively active atmospheric trace constituents

    OpenAIRE

    W. Winiwarter

    2014-01-01

    Radiatively active atmospheric trace constituents consist of the following groups of compounds: long-lived greenhouse gases with residence times of years, subject to international conventions; short-lived gases formed in the atmosphere from precursor compounds, remaining in the atmosphere for hours or days: notably ozone; and aerosols, that is, airborne particles interacting with short-wave radiation with both direct and indirect effects. The "direct effect" covers scattering or absorption of...

  4. High-Accuracy Spectral Lines for Radiation Transport in Stellar Atmospheres

    OpenAIRE

    Amit R. Sharma; Braams, Bastiaan J.; Bowman, Joel M.; Robert Warmbier; Ralf Schneider; Hauschildt, Peter H.

    2008-01-01

    The theory of radiative transfer is an important element for the understanding of the spectral signature and physical structure of stellar atmosphere. PHOENIX1 is a such, very general non-Local Thermodynamic Equilibrium(NLTE) stellar atmosphere computer code which can handle very large model atoms/molecules as well as line blanketing by hundreds of millions of atomic and molecular lines. The code is used to compute model atmospheres and synthetic spectra (solution of the radiative transport e...

  5. Humidity effects on the radiative properties of a hazy atmosphere in the visible spectrum

    OpenAIRE

    Zdunkowski, Wilford G.; Liou, Kuo-Nan

    2011-01-01

    The present investigation deals with the humidity effect on the radiative properties of a strongly polluted atmosphere in the visible spectrum. For three relative humidity distributions covering the tropospheric humidity range from 30–70%, the local albedo, the absorption and transmission of the atmosphere are obtained. Corresponding global quantities are calculated also to speculate on possible climatic effects. Additionally, radiative heating rates are calculated for the entire atmosphere, ...

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

    Science.gov (United States)

    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.

  7. Neutron measuring instruments for radiation protection

    International Nuclear Information System (INIS)

    The present report deals with selected topics from the field of neutron dosimetry for radiation protection connected with the work of the subcommittee 6802 in the Standards Committee on Radiology (NAR) of the German Standards Institute (DIN). It is a sort of material collection. The topics are: 1. Measurement of the absorbed-energy dose by a) ionization chambers in fields of mixed radiation and b) recoil-proton proportional counting tubes. 2. Measurement of the equivalent dose, neutron monitors, combination methods by a) rem-meters, b) recoil-proton counting tubes, c) recombination method, tissue-equivalent proportional counters, activation methods for high energies in fields of mixed radiation, d) personnel dosimetry by means of ionization chambers and counting tubes, e) dosimetry by means of activation methods, nuclear track films, nonphotographic nuclear track detectors and solid-state dosimeters. (orig./HP)

  8. Atmospheric radiative transfer parametrization for solar energy yield calculations on buildings

    CERN Document Server

    Wagner, Jochen E

    2015-01-01

    In this paper the practical approach to evaluate the incoming solar radiation on buildings based on atmospheric composition and cloud cover is presented. The effects of absorption and scattering due to atmospheric composition is taken into account to calculate, using radiative transfer models, the net incoming solar radiation at surface level. A specific validation of the Alpine Region in Europe is presented with a special focus on the region of South Tyrol.

  9. Note: Measurement system for the radiative forcing of greenhouse gases in a laboratory scale.

    Science.gov (United States)

    Kawamura, Yoshiyuki

    2016-01-01

    The radiative forcing of the greenhouse gases has been studied being based on computational simulations or the observation of the real atmosphere meteorologically. In order to know the greenhouse effect more deeply and to study it from various viewpoints, the study on it in a laboratory scale is important. We have developed a direct measurement system for the infrared back radiation from the carbon dioxide (CO2) gas. The system configuration is similar with that of the practical earth-atmosphere-space system. Using this system, the back radiation from the CO2 gas was directly measured in a laboratory scale, which roughly coincides with meteorologically predicted value. PMID:26827362

  10. Note: Measurement system for the radiative forcing of greenhouse gases in a laboratory scale

    International Nuclear Information System (INIS)

    The radiative forcing of the greenhouse gases has been studied being based on computational simulations or the observation of the real atmosphere meteorologically. In order to know the greenhouse effect more deeply and to study it from various viewpoints, the study on it in a laboratory scale is important. We have developed a direct measurement system for the infrared back radiation from the carbon dioxide (CO2) gas. The system configuration is similar with that of the practical earth-atmosphere-space system. Using this system, the back radiation from the CO2 gas was directly measured in a laboratory scale, which roughly coincides with meteorologically predicted value

  11. Note: Measurement system for the radiative forcing of greenhouse gases in a laboratory scale.

    Science.gov (United States)

    Kawamura, Yoshiyuki

    2016-01-01

    The radiative forcing of the greenhouse gases has been studied being based on computational simulations or the observation of the real atmosphere meteorologically. In order to know the greenhouse effect more deeply and to study it from various viewpoints, the study on it in a laboratory scale is important. We have developed a direct measurement system for the infrared back radiation from the carbon dioxide (CO2) gas. The system configuration is similar with that of the practical earth-atmosphere-space system. Using this system, the back radiation from the CO2 gas was directly measured in a laboratory scale, which roughly coincides with meteorologically predicted value.

  12. Note: Measurement system for the radiative forcing of greenhouse gases in a laboratory scale

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, Yoshiyuki [Department of Intelligent Mechanical Engineering, Fukuoka Institute of Technology, 3-30-1 Wajirohigashi, Higashiku, Fukuoka 811-0295 (Japan)

    2016-01-15

    The radiative forcing of the greenhouse gases has been studied being based on computational simulations or the observation of the real atmosphere meteorologically. In order to know the greenhouse effect more deeply and to study it from various viewpoints, the study on it in a laboratory scale is important. We have developed a direct measurement system for the infrared back radiation from the carbon dioxide (CO{sub 2}) gas. The system configuration is similar with that of the practical earth-atmosphere-space system. Using this system, the back radiation from the CO{sub 2} gas was directly measured in a laboratory scale, which roughly coincides with meteorologically predicted value.

  13. A horizontal mobile measuring system for atmospheric quantities

    Directory of Open Access Journals (Sweden)

    J. Hübner

    2014-05-01

    Full Text Available A fully automatic Horizontal Mobile Measuring System (HMMS for atmospheric quantities has been developed. The HMMS is based on the drive mechanism of a garden railway system and can be installed at any location and with any measuring track. In addition to meteorological quantities (temperature, humidity and short/long-wave down/upwelling radiation, HMMS also measures trace gas concentrations (carbon dioxide and ozone. While sufficient spatial resolution is a problem even for measurements on distributed towers, this could be easily achieved with the HMMS, which has been specifically developed to obtain higher information density about horizontal gradients in a heterogeneous forest ecosystem. There, horizontal gradients of meteorological quantities and trace gases could be immense, particularly at the transition from a dense forest to an open clearing, with large impact on meteorological parameters and exchange processes. Consequently, HMMS was firstly applied during EGER IOP3 project (ExchanGE processes in mountainous Regions – Intense Observation Period 3 in the Fichtelgebirge Mountains (SE Germany during summer 2011. At a constant 1 m above ground, the measuring track of the HMMS consisted of a straight line perpendicular to the forest edge, starting in the dense spruce forest and leading 75 m into an open clearing. Tags with bar codes, mounted every meter on the wooden substructure, allowed (a keeping the speed of the HMMS constant (approx. 0.5 m s−1 and (b operation of the HMMS in a continuous back and forth running mode. During EGER IOP3, HMMS was operational for almost 250 h. Results show that – due to considerably long response times (between 4 s and 20 s of commercial temperature, humidity and the radiation sensors – true spatial variations of the meteorological quantities could not be adequately captured (mainly at the forest edge. Corresponding dynamical (spatial errors of the measurement values were corrected on the basis of

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

    Science.gov (United States)

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

    2016-06-01

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

  15. Automatic radiation measuring system connected with GPS

    International Nuclear Information System (INIS)

    The most serious nuclear disaster in Japan has broken out at Fukushima Daiichi Nuclear Power Plant due to Great East Japan Earthquake. Prompt and exact mapping of the contamination is of great importance for radiation protection and for the environment restoration. We have developed radiation survey systems KURAMA and KURAMA-2 for rapid and exact measurement of radiation dose distribution. The system is composed of a mobile radiation monitor and the computer in office which is for the storage and visualization of the data. They are connected with internet and are operated for continuous radiation measurement while the monitor is moving. The mobile part consists of a survey meter, an interface to transform the output of the survey meter for the computer, a global positioning system, a computer to process the data for connecting to the network, and a mobile router. Thus they are effective for rapid mapping of the surface contamination. The operation and the performance of the equipment at the site are presented. (J.P.N.)

  16. Comparison of Martian Surface Radiation Predictions to the Measurements of Mars Science Laboratory Radiation Assessment Detector (MSL/RAD)

    Science.gov (United States)

    Kim, Myung-Hee Y.; Cucinotta, Francis A.; Zeitlin, Cary; Hassler, Donald M.; Ehresmann, Bent; Rafkin, Scot C. R.; Wimmer-Schweingruber, Robert F; Boettcher, Stephan; Boehm, Eckart; Guo, Jingnan; Koehler, Jan; Martin, Cesar; Reitz, Guenther; Posner, Erik

    2014-01-01

    For the analysis of radiation risks to astronauts and planning exploratory space missions, detailed knowledge of particle spectra is an important factor. Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Mars Science Laboratory Radiation Assessment Detector (MSL-RAD) on the Curiosity rover since August 2012, and particle fluxes for a wide range of ion species (up to several hundred MeV/u) and high energy neutrons (8 - 1000 MeV) have been available for the first 200 sols. Although the data obtained on the surface of Mars for 200 sols are limited in the narrow energy spectra, the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code are compared to the data. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used, which includes direct knockout, evaporation and nuclear coalescence. Daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station are implemented into transport calculations for describing the daily column depth of atmosphere. Particles impinging on top of the Martian atmosphere reach the RAD after traversing varying depths of atmosphere that depend on the slant angles, and the model accounts for shielding of the RAD by the rest of the instrument. Calculations of stopping particle spectra are in good agreement with the RAD measurements for the first 200 sols by accounting changing heliospheric conditions and atmospheric pressure. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and thus increase the accuracy of the predictions of future radiation environments on Mars. These contributions lend support to the understanding of radiation health risks to

  17. Comparison of Martian Surface Radiation Predictions to the Measurements of Mars Science Laboratory Radiation Assessment Detector (MSL/RAD)

    Science.gov (United States)

    Kim, M. H. Y.; Cucinotta, F.; Zeitlin, C. J.; Hassler, D.; Ehresmann, B.; Rafkin, S. C.; Wimmer-Schweingruber, R. F.; Böttcher, S. I.; Boehm, E.; Guo, J.; Kohler, J.; Martin-Garcia, C.; Reitz, G.; Posner, A.

    2014-12-01

    For the analysis of radiation risks to astronauts and planning exploratory space missions, detailed knowledge of particle spectra is an important factor. Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Mars Science Laboratory Radiation Assessment Detector (MSL-RAD) on the Curiosity rover since August 2012, and particle fluxes for a wide range of ion species (up to several hundred MeV/u) and high energy neutrons (8 - 1000 MeV) have been available for the first 200 sols. Although the data obtained on the surface of Mars for 200 sols are limited in the narrow energy spectra, the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code are compared to the data. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used, which includes direct knockout, evaporation and nuclear coalescence. Daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station are implemented into transport calculations for describing the daily column depth of atmosphere. Particles impinging on top of the Martian atmosphere reach the RAD after traversing varying depths of atmosphere that depend on the slant angles, and the model accounts for shielding of the RAD by the rest of the instrument. Calculations of stopping particle spectra are in good agreement with the RAD measurements for the first 200 sols by accounting changing heliospheric conditions and atmospheric pressure. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and thus increase the accuracy of the predictions of future radiation environments on Mars. These contributions lend support to the understanding of radiation health risks to

  18. Radiation and Heat Transfer in the Atmosphere: A Comprehensive Approach on a Molecular Basis

    Directory of Open Access Journals (Sweden)

    Hermann Harde

    2013-01-01

    Full Text Available We investigate the interaction of infrared active molecules in the atmosphere with their own thermal background radiation as well as with radiation from an external blackbody radiator. We show that the background radiation can be well understood only in terms of the spontaneous emission of the molecules. The radiation and heat transfer processes in the atmosphere are described by rate equations which are solved numerically for typical conditions as found in the troposphere and stratosphere, showing the conversion of heat to radiation and vice versa. Consideration of the interaction processes on a molecular scale allows to develop a comprehensive theoretical concept for the description of the radiation transfer in the atmosphere. A generalized form of the radiation transfer equation is presented, which covers both limiting cases of thin and dense atmospheres and allows a continuous transition from low to high densities, controlled by a density dependent parameter. Simulations of the up- and down-welling radiation and its interaction with the most prominent greenhouse gases water vapour, carbon dioxide, methane, and ozone in the atmosphere are presented. The radiative forcing at doubled CO2 concentration is found to be 30% smaller than the IPCC-value.

  19. Web based Measurement System for Solar Radiation

    Directory of Open Access Journals (Sweden)

    Shachi Awasthi

    2012-06-01

    Full Text Available We present in this paper, the principles of the measurement system for solar radiation, and our implementation using Web based data logging concept. The photocurrent produced by Silicon PN junction is used as a solar radiation transducer, to make it more viable we have used commercially available solar panels as our transducers. Using a silicon solar cell as sensor, a low cost solar radiometer can be constructed. The photocurrent produced by solar cell is electronically tailored to be measured and stored by our web based data acquisition and monitoring system. Measurement using real solar cell array gives a good measure of actual producible energy by solar arrays. Our portable instrument can be used in remote sites and substitutes the solar monitor and integrator, Current data of solar radiation can be monitored using Ethernet interface available in all PC, Laptops. We store the data into a secure digital card which can be retrieved to plot and analyse the data. We have developed system hardware and software based on ATmega32 AVR Microcontrollers and ENC28J60 Ethernet PHY and MAC network interface chip by Microchip. So the global irradiance data are obtained after correction using the instantaneous measurement of ambient temperature which allows us to calculate the junction temperature and consequently improve the precision of measurement of our data acquisition system.

  20. Measurements of atmospheric fallout in Argentina

    International Nuclear Information System (INIS)

    With the purpose of studying the radioactive fallout present in Argentina from atmospheric nuclear explosions tests that have been conducted recently, an environmental monitoring program, outside the influence of nuclear facilities of Argentina, was undertaken during 1996 and 1997. The levels of Cs-137 and Sr-90 were analysed in samples of air, deposited material (rainwater), milk, an average meal of a standard man and food. During this period, a total of 630 radiochemical analysis were performed on 325 samples of the different matrices described. The concentration levels of the radionuclides analysed in the different environmental matrices are presented and are compared with the values obtained in the environmental monitoring program done during the period 1960-1981. (author)

  1. A photophonic instrument concept to measure atmospheric aerosol absorption. M.S. Thesis

    Science.gov (United States)

    Engle, C. D.

    1982-01-01

    A laboratory model of an instrument to measure the absorption of atmospheric aerosols was designed, built, and tested. The design was based on the photophonic phenomenon discovered by Bell and an acoustic resonator developed by Helmholtz. Experiments were done to show ways the signal amplitude could be improved and the noise reduced and to confirm the instrument was sensitive enough to be practical. The research was undertaken to develop concepts which show promise of being improvements on the instruments that are presently used to measure the absorption of the Sun's radiation by the Earth's atmospheric aerosols.

  2. Direct Measurements of the Surface-Atmosphere Exchange of Ammonia

    Science.gov (United States)

    Tevlin, A.; Murphy, J. G.; Wentworth, G.; Gregoire, P.

    2012-12-01

    As the dominant atmospheric base, ammonia plays an important role in the formation and growth of inorganic aerosols. Surface-atmosphere exchange of ammonia has been observed to occur as a bidirectional flux governed by the relative magnitudes of atmospheric gas phase concentration and a temperature-dependent surface compensation point. In order to better characterise the links between gas-particle and surface-atmosphere exchanges, more direct measurements of these exchanges are necessary. Eddy Covariance (EC) can provide the most direct surface-atmosphere flux measurements, but its requirement for high frequency data combined with the reactive nature of ammonia have limited its application for this species. In order to address this lack, an investigation into the instrumental sensitivity and time response requirements for EC ammonia flux measurements was carried out using a Quantum Cascade-Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS) capable of measuring ammonia concentration at 10 Hz. Time response was additionally improved through the use of a heated sample line and custom glass inlet, and the system was deployed over a short grass field in rural Ontario. The ammonia measurements were used along with three dimensional sonic anemometer wind speed data to calculate EC ammonia fluxes. When combined with simultaneous measurements of the inorganic composition of gas and particle phases made by Ambient Ion Monitor - Ion Chromatography (AIM-IC), these flux measurements can provide insight into the links between gas-particle and surface-atmosphere exchange.

  3. LIDAR for atmospheric backscatter and temperature measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objectives of this effort are to measure atmospheric backscatter profiles and temperature using a zenith looking lidar, designed for a small lander.The lidar...

  4. Solar Radiation Measurements Onboard the Research Aircraft HALO

    Science.gov (United States)

    Lohse, I.; Bohn, B.; Werner, F.; Ehrlich, A.; Wendisch, M.

    2014-12-01

    Airborne measurements of the separated upward and downward components of solar spectral actinic flux densities for the determination of photolysis frequencies and of upward nadir spectral radiance were performed with the HALO Solar Radiation (HALO-SR) instrument package onboard the High Altitude and Long Range Research Aircraft (HALO). The instrumentation of HALO-SR is characterized and first measurement data from the Next-generation Aircraft Remote-Sensing for Validation Studies (NARVAL) campaigns in 2013 and 2014 are presented. The measured data are analyzed in the context of the retrieved microphysical and optical properties of clouds which were observed underneath the aircraft. Detailed angular sensitivities of the two optical actinic flux receivers were determined in the laboratory. The effects of deviations from the ideal response are investigated using radiative transfer calculations of atmospheric radiance distributions under various atmospheric conditions and different ground albedos. Corresponding correction factors are derived. Example photolysis frequencies are presented, which were sampled in the free troposphere and lower stratosphere over the Atlantic Ocean during the 2013/14 HALO NARVAL campaigns. Dependencies of photolysis frequencies on cloud cover, flight altitude and wavelength range of the photolysis process are investigated. Calculated actinic flux densities in the presence of clouds benefit from the measured spectral radiances. Retrieved cloud optical thicknesses and effective droplet radii are used as model input for the radiative transfer calculations. By comparison with the concurrent measurements of actinic flux densities the retrieval approach is validated. Acknowledgements: Funding by the Deutsche Forschungsgemeinschaft within the priority program HALO (BO 1580/4-1, WE 1900/21-1) is gratefully acknowledged.

  5. The SARTre model for radiative transfer in spherical atmospheres and its application to the derivation of cirrus cloud properties

    Energy Technology Data Exchange (ETDEWEB)

    Mendrock, J.

    2006-07-01

    Modeling of radiative transfer (RT) is one of the essentials of atmospheric remote sensing. It has been common to use separate models for the simulation of shortwave radiation dominated by scattering of sunlight and longwave radiation characterized by emission from trace gases. These days also shortwave instruments are operated in limb mode, which demand models taking the sphericity of the Earth and atmosphere into account. On the other hand, infrared and microwave sounders are increasingly being used for the observation of ice clouds, that necessitate the modeling of scattering by cloud particles. Both trends require RT models, that are capable of taking into account scattering as well as the sphericity of the atmosphere. This suggests a unified handling of short- and longwave radiation, which furthermore allows for a consistent evaluation of multispectral data. Focusing on these aspects, the RT-model SARTre ([Approximate] Spherical Atmospheric Radiative Transfer model) has been developed. To our knowledge, SARTre is the first model, that is capable of limb modeling in the ultraviolet, visible, near to far infrared, and microwave spectral region. Here, algorithm baseline, implementation, verification and validation of SARTre are presented. SARTre has been used to study effects of cirrus clouds on infrared limb emission spectra. An exemplary retrieval of cirrus parameters from MIPAS measurements is demonstrated, and the plausibility of the results is discussed. (orig.)

  6. Absorption of infra-red radiation by atmospheric molecular cluster-ions

    CERN Document Server

    Aplin, K L

    2005-01-01

    Protonated water clusters are a common species of atmospheric molecular cluster-ion, produced by cosmic rays throughout the troposphere and stratosphere. Under clear-sky conditions or periods of increased atmospheric ionisation, such as solar proton events, the IR absorption by atmospheric ions may affect climate through the radiative balance. Fourier Transform Infrared Spectrometry in a long path cell, of path length 545m, has been used to detect IR absorption by corona-generated positive molecular cluster-ions. The column concentration of ions in the laboratory spectroscopy experiment was estimated to be ~10^13 m-2; the column concentration of protonated atmospheric ions estimated using a simple model is ~10^14 m-2. Two regions of absorption, at 12.3 and 9.1 um are associated with enhanced ion concentrations. After filtering of the measured spectra to compensate for spurious signals from neutral water vapour and residual carbon dioxide, the strongest absorption region is at 9.5 to 8.8 um (1050 to 1140 cm-1)...

  7. Deviating measurements in radiation protection. Legal assessment of deviations in radiation protection measurements

    International Nuclear Information System (INIS)

    This study investigates how, from a legal point of view, deviations in radiation protection measurements should be treated in comparisons between measured results and limits stipulated by nuclear legislation or goods transport regulations. A case-by-case distinction is proposed which is based on the legal concequences of the respective measurement. Commentaries on nuclear law contain no references to the legal assessment of deviating measurements in radiation protection. The examples quoted in legal commentaries on civil and criminal proceedings of the way in which errors made in measurements for speed control and determinations of the alcohol content in the blood are to be taken into account, and a commentary on ozone legislation, are examined for analogies with radiation protection measurements. Leading cases in the nuclear field are evaluated in the light of the requirements applying in case of deviations in measurements. The final section summarizes the most important findings and conclusions. (orig.)

  8. Short-wave solar radiation in the earths atmosphere calculation, observation, interpretation

    CERN Document Server

    Melnikova, Irina N

    2005-01-01

    Based on data from an experiment which ran for ten years, this book summarizes the results of the Atmospheric Physics Department of the St. Petersburg University and the Main Geophysical Observatory. The processed data now forms a rich dataset of spectral values of radiative characteristics under different atmospheric conditions. The analysis of this database clearly shows that the solar radiative absorption in a dusty and cloudy atmosphere is significantly higher than assumed to date. Both graduate students of atmospheric sciences as well as scientists and researchers in the field of meteorology and climatology will find a wealth of new data and information in this monograph.

  9. Atmospheric Airborne Pressure Measurements Using the Oxygen A Band for the ASCENDS Mission

    Science.gov (United States)

    Rodriguez, M.; Riris, H.; Abshire, J. B.; Allan, G. R.; Stephen, M.; Hasselbrack, W.; Mao, J.

    2012-12-01

    We report on airborne atmospheric pressure measurements using fiber-based laser technology and the oxygen A-band at 765 nm. Remote atmospheric temperature and pressure measurements are needed for NASA's Active Sensing of CO2 Emissions Over Nights, Days, and Seasons (ASCENDS) mission. ASCENDS will measure atmospheric CO2 dry mixing ratios on a global scale. Remote atmospheric pressure measurements are necessary to normalize ASCENDS CO2 measurements. Our work, funded by the ESTO IIP program, uses erbium doped fiber optic amplifiers and non-linear optics technology to tune laser radiation over the Oxygen A-band between 764.5 nm and 765 nm. Surface reflections are fiber-coupled from a receiver telescope to photon counting detectors. Our pulsed, time gated approach resolves ground reflections from cloud returns. This system successfully recorded O2 absorption spectra during two airborne campaigns aboard a NASA DC-8. Airborne data has been analyzed and fitted to HITRAN reference spectra based upon aircraft meteorological data. Our algorithm linearly scales the HITRAN reference until measurement errors are minimized. Atmospheric pressure changes are estimated by comparing the differential optical depth of the optimum scaled HITRAN spectra to the differential optical depth of the nominal HITRAN spectra. On flights over gradually sloping terrain, these results compare favorably with ground-based observations and predictions from computer models. Measurement uncertainty is commensurate with photon counting noise. We plan to reduce measurement uncertainty in future campaigns by improving transmitter pulse energy and increasing wavelength sweep frequency.

  10. Statistics for Radiation Measurement. Chapter 5

    International Nuclear Information System (INIS)

    Measurement errors are of three general types: (i) blunders, (ii) systematic errors or accuracy of measurements, and (iii) random errors or precision of measurements. Blunders produce grossly inaccurate results and experienced observers easily detect their occurrence. Examples in radiation counting or measurements include the incorrect setting of the energy window, counting heavily contaminated samples, using contaminated detectors for imaging or counting, obtaining measurements of high activities, resulting in count rates that lead to excessive dead time effects, and selecting the wrong patient orientation during imaging. Although some blunders can be detected as outliers or by duplicate samples and measurements, blunders should be avoided by careful, meticulous and dedicated work. This is especially important where results will determine the diagnosis or treatment of patients

  11. The Role of Atmospheric Measurements in Wind Power Statistical Models

    Science.gov (United States)

    Wharton, S.; Bulaevskaya, V.; Irons, Z.; Newman, J. F.; Clifton, A.

    2015-12-01

    The simplest wind power generation curves model power only as a function of the wind speed at turbine hub-height. While the latter is an essential predictor of power output, it is widely accepted that wind speed information in other parts of the vertical profile, as well as additional atmospheric variables including atmospheric stability, wind veer, and hub-height turbulence are also important factors. The goal of this work is to determine the gain in predictive ability afforded by adding additional atmospheric measurements to the power prediction model. In particular, we are interested in quantifying any gain in predictive ability afforded by measurements taken from a laser detection and ranging (lidar) instrument, as lidar provides high spatial and temporal resolution measurements of wind speed and direction at 10 or more levels throughout the rotor-disk and at heights well above. Co-located lidar and meteorological tower data as well as SCADA power data from a wind farm in Northern Oklahoma will be used to train a set of statistical models. In practice, most wind farms continue to rely on atmospheric measurements taken from less expensive, in situ instruments mounted on meteorological towers to assess turbine power response to a changing atmospheric environment. Here, we compare a large suite of atmospheric variables derived from tower measurements to those taken from lidar to determine if remote sensing devices add any competitive advantage over tower measurements alone to predict turbine power response.

  12. Atmospheric propagation of high power laser radiation at different weather conditions

    Science.gov (United States)

    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.

  13. Analysis of a Kalman filter based method for on-line estimation of atmospheric dispersion parameters using radiation monitoring data

    DEFF Research Database (Denmark)

    Drews, Martin; Lauritzen, Bent; Madsen, Henrik

    2005-01-01

    A Kalman filter method is discussed for on-line estimation of radioactive release and atmospheric dispersion from a time series of off-site radiation monitoring data. The method is based on a state space approach, where a stochastic system equation describes the dynamics of the plume model...... parameters, and the observables are linked to the state variables through a static measurement equation. The method is analysed for three simple state space models using experimental data obtained at a nuclear research reactor. Compared to direct measurements of the atmospheric dispersion, the Kalman filter...... estimates are found to agree well with the measured parameters, provided that the radiation measurements are spread out in the cross-wind direction. For less optimal detector placement it proves difficult to distinguish variations in the source term and plume height; yet the Kalman filter yields consistent...

  14. Web based Measurement System for Solar Radiation

    Directory of Open Access Journals (Sweden)

    Shachi Awasthi

    2012-06-01

    Full Text Available We present in this paper, the principles of themeasurement system for solar radiation, and ourimplementation using Web based data loggingconcept.The photocurrent produced by Silicon PNjunction is used as a solar radiation transducer, tomake it more viable we have used commerciallyavailable solar panels as our transducers. Using asilicon solar cell as sensor, a low cost solarradiometer can be constructed. The photocurrentproduced by solar cell is electronically tailored to bemeasured and stored by our web based dataacquisition and monitoring system. Measurementusing real solar cell array gives a good measure ofactual producible energy by solar arrays. Ourportable instrument can be used in remote sites andsubstitutes the solar monitor and integrator,Current data of solar radiation can be monitoredusing Ethernet interface available in all PC,Laptops. We store the data into a secure digital cardwhich can be retrieved to plot and analyse the data.We have developed system hardware andsoftware based on ATmega32 AVR Microcontrollersand ENC28J60 Ethernet PHY and MAC networkinterface chip by Microchip.So the global irradiance data are obtained aftercorrection using the instantaneous measurement ofambient temperature which allows us to calculatethe junction temperature and consequently improvethe precision of measurement of our dataacquisition system

  15. Development of prototype fiber optics dosimeter for remote radiation measurements

    International Nuclear Information System (INIS)

    Optical fiber dosimetry has been studied as an emerging method of monitoring radiation remotely in difficult to access and hazardous areas and is suitable for use in confined environments that may be inaccessible using existing dosimeters. Being light weight and non intrusive, optical fibers provide several advantages in the field of dosimetry like resistant to electromagnetic interferences. An extrinsic architecture, where the radiation-sensing component is spliced or coupled to an optical fiber, is employed in this work. A prototype single channel fiber optic based remote radiation measurement system with BaFBr:Eu sensor, which has a wide linear dose response, is developed at Radiological Safety Division, IGCAR. High sensitive BaFBr:Eu2+ storage phosphor of 10 mm dia and 4 mm thickness has been successfully synthesized using high temperature solid state diffusion route in a reducing atmosphere. Optical characteristics of the BaFBr:Eu pellet were studied by taking Photoluminescence (PL) and Photo stimulated luminescence (PSL) measurements. PL emission wavelength is measured to be 390 nm. The BaFBr:Eu is irradiated for various absorbed doses in a gamma chamber at 213 Gy/hr using 60Co standard source (BRIT make) available at RSD, IGCAR

  16. Measuring and prediction of global solar ultraviolet radiation (0295-0385 μ m) under clear and cloudless skies

    International Nuclear Information System (INIS)

    Values of global solar ultraviolet radiation were measured with an ultraviolet radiometer and also predicted with a atmospheric spectral model. The values obtained with the atmospheric spectral model, based physically, were analyzed and compared with experimental values measured in situ. Measurements were performed for different zenith angles in conditions of clear skies in Heredia, Costa Rica. The necessary input data include latitude, altitude, surface albedo, Earth-Sun distance, as well as atmospheric characteristics: atmospheric turbidity, precipitable water and atmospheric ozone. The comparison between measured and predicted values have been successful. (author)

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

    OpenAIRE

    Aplin, Karen; Lockwood, Mike

    2015-01-01

    Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing traditionally distinct scientific boundaries. Following the paper of Erlykin et al. (Astropart. Phys. 57--58 (2014) 26--29) we develop the interpretation of observed changes in long-wave (LW) radiation (Aplin and Lockwood, Env. Res. Letts. 8, 015026 (2013)), by taking account of cosmic ray ionisation yields and atmospheric radiative transfer. To demonstrate this, we show that the thermal stru...

  18. Atmospheric Effects on InSAR Measurements and Their Mitigation

    Directory of Open Access Journals (Sweden)

    Jiang-ping Long

    2008-09-01

    Full Text Available Interferometric Synthetic Aperture Radar (InSAR is a powerful technology for observing the Earth surface, especially for mapping the Earth's topography and deformations. InSAR measurements are however often significantly affected by the atmosphere as the radar signals propagate through the atmosphere whose state varies both in space and in time. Great efforts have been made in recent years to better understand the properties of the atmospheric effects and to develop methods for mitigating the effects. This paper provides a systematic review of the work carried out in this area. The basic principles of atmospheric effects on repeat-pass InSAR are first introduced. The studies on the properties of the atmospheric effects, including the magnitudes of the effects determined in the various parts of the world, the spectra of the atmospheric effects, the isotropic properties and the statistical distributions of the effects, are then discussed. The various methods developed for mitigating the atmospheric effects are then reviewed, including the methods that are based on PSInSAR processing, the methods that are based on interferogram modeling, and those that are based on external data such as GPS observations, ground meteorological data, and satellite data including those from the MODIS and MERIS. Two examples that use MODIS and MERIS data respectively to calibrate atmospheric effects on InSAR are also given.

  19. Upconversion-based lidar measurements of atmospheric CO2

    DEFF Research Database (Denmark)

    Høgstedt, Lasse; Fix, Andreas; Wirth, Martin;

    2016-01-01

    For the first time an upconversion based detection scheme is demonstrated for lidar measurements of atmospheric CO2-concentrations, with a hard target at a range of 3 km and atmospheric backscatter from a range of similar to 450 m. The pulsed signals at 1572 nm are upconverted to 635 nm, and dete......For the first time an upconversion based detection scheme is demonstrated for lidar measurements of atmospheric CO2-concentrations, with a hard target at a range of 3 km and atmospheric backscatter from a range of similar to 450 m. The pulsed signals at 1572 nm are upconverted to 635 nm......, and detected by a photomultiplier tube, to test how the upconversion technology performs in a long range detection system. The upconversion approach is compared to an existing direct detection scheme using a near-IR detector with respect to signal-to-noise ratio and quantum efficiency. It is for the first time...

  20. Estimate of the atmospheric turbidity from three broad-band solar radiation algorithms. A comparative study

    Directory of Open Access Journals (Sweden)

    G. López

    2004-09-01

    Full Text Available Atmospheric turbidity is an important parameter for assessing the air pollution in local areas, as well as being the main parameter controlling the attenuation of solar radiation reaching the Earth's surface under cloudless sky conditions. Among the different turbidity indices, the Ångström turbidity coefficient β is frequently used. In this work, we analyse the performance of three methods based on broad-band solar irradiance measurements in the estimation of β. The evaluation of the performance of the models was undertaken by graphical and statistical (root mean square errors and mean bias errors means. The data sets used in this study comprise measurements of broad-band solar irradiance obtained at eight radiometric stations and aerosol optical thickness measurements obtained at one co-located radiometric station. Since all three methods require estimates of precipitable water content, three common methods for calculating atmospheric precipitable water content from surface air temperature and relative humidity are evaluated. Results show that these methods exhibit significant differences for low values of precipitable water. The effect of these differences in precipitable water estimates on turbidity algorithms is discussed. Differences in hourly turbidity estimates are later examined. The effects of random errors in pyranometer measurements and cloud interferences on the performance of the models are also presented. Examination of the annual cycle of monthly mean values of β for each location has shown that all three turbidity algorithms are suitable for analysing long-term trends and seasonal patterns.

  1. Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS)

    Energy Technology Data Exchange (ETDEWEB)

    Bland, Geoffrey [NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)

    2016-06-30

    The use of small unmanned aircraft systems (sUAS) with miniature sensor systems for atmospheric research is an important capability to develop. The Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS) project, lead by Dr. Gijs de Boer of the Cooperative Institute for Research in Environmental Sciences (CIRES- a partnership of NOAA and CU-Boulder), is a significant milestone in realizing this new potential. This project has clearly demonstrated that the concept of sUAS utilization is valid, and miniature instrumentation can be used to further our understanding of the atmospheric boundary layer in the arctic.

  2. Vector radiative transfer numerical model of coupled ocean-atmosphere system using matrix-operator method

    Institute of Scientific and Technical Information of China (English)

    HE XianQiang; PAN DeLu; BAI Yan; ZHU QianKun; GONG Fang

    2007-01-01

    A vector radiative transfer numerical model of the coupled ocean-atmosphere system is developed based on the matrix-operator method,which is named PCOART.Using the Fourier analysis,the vector radiative transfer equation (VRTE) is separated into a set of equations depending only on the observation zenith angle.Using the Gaussian-Quadrature method,VRTE is finally transferred into the matrix equation solved by the adding-doubling method.According to the reflective and refractive properties of the ocean-atmosphere interface,the vector radiative transfer numerical model of the ocean and atmosphere is coupled in PCOART.Compared with the exact Rayleigh scattering look-up tables of MODIS (Moderate-resolution Imaging Spectroradiometer),it is shown that PCOART is an exactly numerical model,and the processing methods of the multi-scattering and polarization are correct.Also,validated with the standard problems of the radiative transfer in water,it is shown that PCOART can be used to calculate the underwater radiative transfer problems.Therefore,PCOART is a useful tool for exactly calculating the vector radiative transfer of the coupled ocean-atmosphere system,which can be used to study the polarization properties of the radiance in the whole ocean-atmosphere system and the remote sensing of the atmosphere and ocean.

  3. Vector radiative transfer numerical model of coupled ocean-atmosphere system using matrix-operator method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A vector radiative transfer numerical model of the coupled ocean-atmosphere system is developed based on the matrix-operator method, which is named PCOART. Using the Fourier analysis, the vector radiative transfer equation (VRTE) is separated into a set of equations depending only on the observa-tion zenith angle. Using the Gaussian-Quadrature method, VRTE is finally transferred into the matrix equation solved by the adding-doubling method. According to the reflective and refractive properties of the ocean-atmosphere interface, the vector radiative transfer numerical model of the ocean and at-mosphere is coupled in PCOART. Compared with the exact Rayleigh scattering look-up tables of MODIS (Moderate-resolution Imaging Spectroradiometer), it is shown that PCOART is an exactly numerical model, and the processing methods of the multi-scattering and polarization are correct. Also, validated with the standard problems of the radiative transfer in water, it is shown that PCOART can be used to calculate the underwater radiative transfer problems. Therefore, PCOART is a useful tool for exactly calculating the vector radiative transfer of the coupled ocean-atmosphere system, which can be used to study the polarization properties of the radiance in the whole ocean-atmosphere system and the remote sensing of the atmosphere and ocean.

  4. Measurement of Thermal Radiation Properties of Solids

    Science.gov (United States)

    Richmond, J. C. (Editor)

    1963-01-01

    The overall objectives of the Symposium were to afford (1) an opportunity for workers in the field to describe the equipment and procedures currently in use for measuring thermal radiation properties of solids, (2) an opportunity for constructive criticism of the material presented, and (3) an open forum for discussion of mutual problems. It was also the hope of the sponsors that the published proceedings of the Symposium would serve as a valuable reference on measurement techniques for evaluating thermal radiation properties of solids, partic.ularly for those with limited experience in the field. Because of the strong dependence of emitted flux upon temperature, the program committee thought it advisable to devote the first session to a discussion of the problems of temperature measurement. All of the papers in Session I were presented at the request of and upon topics suggested by the Committee. Because of time and space limitations, it, was impossible to consider all temperature measurement problems that might arise--the objective was rather to call to the attention of the reader some of the problems that might be encountered, and to provide references that might provide solutions.

  5. Estimations of climate sensitivity based on top-of-atmosphere radiation imbalance

    Directory of Open Access Journals (Sweden)

    B. Lin

    2010-02-01

    Full Text Available Large climate feedback uncertainties limit the accuracy in predicting the response of the Earth's climate to the increase of CO2 concentration within the atmosphere. This study explores a potential to reduce uncertainties in climate sensitivity estimations using energy balance analysis, especially top-of-atmosphere (TOA radiation imbalance. The time-scales studied generally cover from decade to century, that is, middle-range climate sensitivity is considered, which is directly related to the climate issue caused by atmospheric CO2 change. The significant difference between current analysis and previous energy balance models is that the current study targets at the boundary condition problem instead of solving the initial condition problem. Additionally, climate system memory and deep ocean heat transport are considered. The climate feedbacks are obtained based on the constraints of the TOA radiation imbalance and surface temperature measurements of the present climate. In this study, the TOA imbalance value of 0.85 W/m2 is used. Note that this imbalance value has large uncertainties. Based on this value, a positive climate feedback with a feedback coefficient ranging from −1.3 to −1.0 W/m2/K is found. The range of feedback coefficient is determined by climate system memory. The longer the memory, the stronger the positive feedback. The estimated time constant of the climate is large (70~120 years mainly owing to the deep ocean heat transport, implying that the system may be not in an equilibrium state under the external forcing during the industrial era. For the doubled-CO2 climate (or 3.7 W/m2 forcing, the estimated global warming would be 3.1 K if the current estimate of 0.85 W/m2 TOA net radiative heating could be confirmed. With accurate long-term measurements of TOA radiation, the analysis method suggested by this study provides a great potential in the

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

    Science.gov (United States)

    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

  7. Mobile Atmospheric Aerosol and Radiation Characterization Observatory (MAARCO)

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: MAARCO is designed as a stand-alone facility for basic atmospheric research and the collection of data to assist in validating aerosol and weather models....

  8. Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS) Science Plan

    Energy Technology Data Exchange (ETDEWEB)

    de Boer, G [University of Colorado, Boulder/CIRES; Argrow, B [University of Colorado; Bland, G [NASA - Goddard Space Flight Center - Wallops Flight Facility; Elston, J [University of Colorado, Boulder; Lawrence, D [University of Colorado; Maslanik, J [University of Colorado; Palo, S [University of Colorado; Tschudi, M [NCAR

    2015-12-01

    The use of unmanned aerial systems (UAS) is becoming increasingly popular for a variety of applications. One way in which these systems can provide revolutionary scientific information is through routine measurement of atmospheric conditions, particularly properties related to clouds, aerosols, and radiation. Improved understanding of these topics at high latitudes, in particular, has become very relevant because of observed decreases in ice and snow in polar regions.

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

    Science.gov (United States)

    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. Fractional integration and radiative transfer in a multifractal atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Naud, C.; Schertzer, D. [Universite Pierre et Marie Curie, Paris (France); Lovejoy, S. [McGill Univ., Montreal (Canada)

    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.

  11. Radiated BPF sound measurement of centrifugal compressor

    International Nuclear Information System (INIS)

    A technique to measure radiated BPF sound from an automotive turbocharger compressor impeller is proposed in this paper. Where there are high-level background noises in the measurement environment, it is difficult to discriminate the target component from the background. Since the effort of measuring BPF sound was taken in a room with such condition in this study, no discrete BPF peak was initially found on the sound spectrum. Taking its directionality into consideration, a microphone covered with a parabolic cone was selected and using this technique, the discrete peak of BPF was clearly observed. Since the level of measured sound was amplified due to the area-integration effect, correction was needed to obtain the real level. To do so, sound measurements with and without a parabolic cone were conducted for the fixed source and their level differences were used as correction factors. Consideration is given to the sound propagation mechanism utilizing measured BPF as well as the result of a simple model experiment. The present method is generally applicable to sound measurements conducted with a high level of background noise

  12. Radiated BPF sound measurement of centrifugal compressor

    Science.gov (United States)

    Ohuchida, S.; Tanaka, K.

    2013-12-01

    A technique to measure radiated BPF sound from an automotive turbocharger compressor impeller is proposed in this paper. Where there are high-level background noises in the measurement environment, it is difficult to discriminate the target component from the background. Since the effort of measuring BPF sound was taken in a room with such condition in this study, no discrete BPF peak was initially found on the sound spectrum. Taking its directionality into consideration, a microphone covered with a parabolic cone was selected and using this technique, the discrete peak of BPF was clearly observed. Since the level of measured sound was amplified due to the area-integration effect, correction was needed to obtain the real level. To do so, sound measurements with and without a parabolic cone were conducted for the fixed source and their level differences were used as correction factors. Consideration is given to the sound propagation mechanism utilizing measured BPF as well as the result of a simple model experiment. The present method is generally applicable to sound measurements conducted with a high level of background noise.

  13. Measuring concentrations of elements using neutron radiation

    International Nuclear Information System (INIS)

    An apparatus for measuring the concentrations of elements in a material by the capture gamma method is claimed. The apparatus comprises either an isotope source or a neutron generator as the neutron source, a semi-conductor detector as the gamma-radiation detector, and a moderator which is, at least in part, heavy water. The detector is adapted to be placed adjacent to or inside a specimen in the flux of slow neutrons so that sufficient moderator is disposed between the source and the sample-detector combination that only relatively few fast neutrons will reach the detector

  14. Solar Radiation: Models and Measurement Techniques

    Directory of Open Access Journals (Sweden)

    C. K. Pandey

    2013-01-01

    Full Text Available In order to grasp the significance of the work accomplished by the author, it is necessary to keep abreast of the present developments in this field. The research work reported in the paper is an attempt to get knowledge to assess the solar energy potential for practical and efficient utilization in India. Our work is centered on estimating realistic values of solar (global and diffuse radiation on horizontal and tilted surfaces using measured meteorological data and geographical and geometrical parameters for India.

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

    Science.gov (United States)

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

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

  16. Study of cloud enhanced surface UV radiation at the atmospheric observatory of Southern Patagonia, Río Gallegos, Argentina

    Science.gov (United States)

    Wolfram, Elian A.; Salvador, Jacobo; Orte, Facundo; Bulnes, Daniela; D'Elia, Raul; Antón, Manuel; Alados-Arboledas, Lucas; Quel, Eduardo

    2013-05-01

    Ozone and ultraviolet (UV) radiation are two important issues in the study of Earth's atmosphere. The anthropogenic perturbation of the ozone layer has induced change in the amount of UV radiation that reaches the Earth's surface, mainly through the Antarctic ozone hole. Also clouds have been identified as the main modulator of UV amount over short time scales. While clouds can decrease direct radiation, they can produce an increase in the diffuse component, and as a consequence the surface UV radiation may be higher than during an equivalent clear sky scenario. In particular this situation can be important when a low ozone column and partially cloud coverered skies occur simultaneously. These situations happen frequently in southern Patagonia, where the CEILAP Lidar Division has established the Atmospheric Observatory of Southern Patagonia, an atmospheric remote sensing site near the city of Río Gallegos (51°55'S, 69°14'W). In this paper, the impact of clouds on UV radiation is investigated by the use of ground based measurements from the passive remote sensing instruments operating at this site, mainly broad and moderate narrow band filter radiometers. Cloud modification factors (CMF, ratio between the measured UV radiation in a cloudy sky and the simulated radiation under cloud-free conditions) are evaluated for the study site. CMFs higher than 1 are found during spring and summer time, when lower total ozone columns, higher solar elevations and high cloud cover occur simultaneously, producing extreme erythemal irradiance at the ground surface. Enhancements as high as 25% were registered. The maximum duration of the enhancement was around 30 minutes. This produces dangerous sunbathing conditions for the Río Gallegos citizen.

  17. A new method to retrieve the aerosol layer absorption coefficient from airborne flux density and actinic radiation measurements

    OpenAIRE

    Bierwirth, Eike; Wendisch, Manfred; Jäkel, Evelyn; Ehrlich, André; Schmidt, K. Sebastian; Stark, Harald; Pilewskie, Peter; Esselborn, Michael; Gobbi, Gian Paolo; Ferrare, Richard; Müller, Thomas; Clarke, Antony

    2010-01-01

    A new method is presented to derive the mean value of the spectral absorption coefficient of an aerosol layer from combined airborne measurements of spectral net irradiance and actinic flux density. While the method is based on a theoretical relationship of radiative transfer theory, it is applied to atmospheric radiation measurements for the first time. The data have been collected with the Spectral Modular Airborne Radiation Measurement System (SMART‐Albedometer), the Solar Spectral Fl...

  18. Altitude profile of aerosols on Mars from measurements of its thermal radiation on limb

    Science.gov (United States)

    Moroz, V. I.; Titov, D. V.; Gektin, Yu. M.; Naraeva, M. K.; Selivanov, A. S.

    1993-01-01

    Measurements of the thermal (range 7 - 13 micrometers) radiation of Mars with the high space resolution (approximately 2 km) were made by the TERMOSKAN experiment of the Phobos mission. Some of the results were published earlier but only the surface radiation was analyzed in detail. However some part of these measurements was made near the limb of the planet. The atmosphere gives an important input here in the planetary thermal radiation. Beyond the limb the atmosphere is the only source. The task of this work is to estimate some characteristics of the atmosphere using brightness profiles of the thermal radiation near the limb. An appropriate model of the temperature profile T(h) is necessary for such an analysis. A set of T(h) models (nominal, maximal and minimal) was defined using various sources including MARSGRAM, Viking-1 lander data, its theoretical considerations and boundary layer models. On the next step the possible input of the atmospheric gaseous emissions (wing of CO2 15 micrometer band) was estimated. It was found that even for the maximal T(h) this input is no more than a few percents of the measured radiation beyond the limb. Consequently the aerosols are responsible for almost all measured emission. The analysis of the observed profile showed that these aerosols have two components: (1) exponential with the scale height about 10 km and (2) some layered structure (two layers with maxima about 23 and 33 km consisted probably of ice).

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

    Science.gov (United States)

    Hollstein, André; Fischer, Jürgen

    2012-05-01

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

  20. Simultaneous measurements of atmospheric emissions at 10, 33 and 90 GHz

    International Nuclear Information System (INIS)

    As part of a larger experiment to measure the cosmic microwave background radiation spectrum, frequent simultaneous measurements of the microwave thermal emission from the earth's atmosphere were made at three fixed frequencies, namely, 10 GHz, 33 GHz and 90 GHz. We performed these measurements at two separate locations, Berkeley and White Mountain, which greatly differed in altitude and climatic conditions. Typical values measured in Berkeley of the atmospheric antenna temperature during good weather are 3.13 +- 0.300K, 12.3 +- 0.30K and 34.6 +- 0.50K, for 10, 33, and 90 GHz respectively. Corresponding values measured at White Mountain are 1.15 +- 0.10K, 4.51 +- 0.180K and 11.0 +- 0.20K. Because the measurements are simultaneous in nature, correlations between the measurements taken at the various frequencies provide constraints on models of the microwave emission of the earth's atmosphere, especially models describing atmospheric emission as a function of precipitable water content

  1. Impact of Atmospheric Attenuations Time Resolutions in Solar Radiation Derived from Satellite Imagery

    Science.gov (United States)

    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

  2. Atmospheric Airborne Pressure Measurements Using the Oxygen A Band for the ASCENDS Mission

    Science.gov (United States)

    Riris, Haris; Rodriguez, Mike; Stephen, Mark; Hasselbrack, William; Allan, Graham; Mao, Jiamping,; Kawa, Stephan R.; Weaver, Clark J.

    2011-01-01

    We report on airborne atmospheric pressure measurements using new fiber-based laser technology and the oxygen A-band at 765 nm. Remote measurements of atmospheric temperature and pressure are required for a number of NASA Earth science missions and specifically for the Active Sensing of CO2 Emissions Over Nights, Days, and Seasons (ASCENDS) mission. Accurate measurements of tropospheric CO2 on a global scale are very important in order to better understand its sources and sinks and to improve predictions on any future climate change. The ultimate goal of a CO2 remote sensing mission, such as ASCENDS, is to derive the CO2 concentration in the atmosphere in terms of mole fraction in unit of parts-per-million (ppmv) with regard to dry air. Therefore, both CO2 and the dry air number of molecules in the atmosphere are needed in deriving this quantity. O2 is a stable molecule and uniformly mixed in the atmosphere. Measuring the O2 absorption in the atmosphere can thus be used to infer the dry air number of molecules and then used to calculate CO2 concentration. With the knowledge of atmospheric water vapor, we can then estimate the total surface pressure needed for CO2 retrievals. Our work, funded by the ESTO IIP program, uses fiber optic technology and non-linear optics to generate 765 nm laser radiation coincident with the Oxygen A-band. Our pulsed, time gated technique uses several on- and off-line wavelengths tuned to the O2 absorption line. The choice of wavelengths allows us to measure the pressure by using two adjacent O2 absorptions in the Oxygen A-band. Our retrieval algorithm fits the O2 lineshapes and derives the pressure. Our measurements compare favorably with a local weather monitor mounted outside our laboratory and a local weather station.

  3. Atmospheric aerosol characterization combining multi-wavelength Raman lidar and MAX-DOAS measurements in Gwanjgu

    Science.gov (United States)

    Chong, Jihyo; Shin, Dong Ho; Kim, Kwang Chul; Lee, Kwon-Ho; Shin, Sungkyun; Noh, Young M.; Müller, Detlef; Kim, Young J.

    2011-11-01

    Integrated approach has been adopted at the ADvanced Environmental Research Center (ADEMRC), Gwangju Institute of Science and Technology (GIST), Korea for effective monitoring of atmospheric aerosol. Various active and passive optical remote sensing techniques such as multi-wavelength (3β+2α+1δ) Raman LIDAR, sun-photometry, MAX-DOAS, and satellite retrieval have been utilized. This integrated monitoring system approach combined with in-situ surface measurement is to allow better characterization of physical and optical properties of atmospheric aerosol. Information on the vertical distribution and microphysical properties of atmospheric aerosol is important for understanding its transport characteristics as well as radiative effect. The GIST multi-wavelength (3β + 2α+1δ) Raman lidar system can measure vertical profiles of optical properties of atmospheric aerosols such as extinction coefficients at 355 and 532nm, particle backscatter coefficients at 355, 532 and 1064 nm, and depolarization ratio at 532nm. The incomplete overlap between the telescope field-of-view and beam divergence of the transmitting laser significantly affects lidar measurement, resulting in higher uncertainty near the surface where atmospheric aerosols of interest are concentrated. Differential Optical Absorption Spectroscopy (DOAS) technique is applied as a complementary tool for the detection of atmospheric aerosols near the surface. The passive Multi-Axis DOAS (MAX-DOAS) technique uses scattered sunlight as a light source from several viewing directions. Recently developed aerosol retrieval algorithm based on O4 slant column densities (SCDs) measured at UV and visible wavelengths has been utilized to derive aerosol information (e.g., aerosol optical depth (AOD) and aerosol extinction coefficients (AECs)) in the lower troposphere. The aerosol extinction coefficient at 356 nm was retrieved for the 0-1 and 1-2 km layers based on the MAX-DOAS measurements using the retrieval algorithm

  4. Radiative lifetime measurements of rubidium Rydberg states

    CERN Document Server

    Branden, Drew B; Mahlokozera, Tatenda; Vesa, Cristian; Wilson, Roy O; Zheng, Mao; Kortyna, Andrew; Tate, Duncan A

    2009-01-01

    We have measured the radiative lifetimes of ns, np and nd Rydberg states of rubidium in the range 28 < n < 45. To enable long-lived states to be measured, our experiment uses slow-moving Rb atoms in a magneto-optical trap (MOT). Two experimental techniques have been adopted to reduce random and systematic errors. First, a narrow-bandwidth pulsed laser is used to excite the target Rydberg state, resulting in minimal shot-to-shot variation in the initial state population. Second, we monitor the target state population as a function of time delay from the laser pulse using a short-duration, millimetre-wave pulse that is resonant with a one- or two-photon transition. We then selectively field ionize the monitor state, and detect the resulting electrons with a micro-channel plate. This signal is an accurate mirror of the target state population, and is uncontaminated by contributions from other states which are populated by black body radiation. Our results are generally consistent with other recent experime...

  5. Regional modelling of Saharan dust and biomass-burning smoke. Part 2: Direct radiative forcing and atmospheric dynamic response

    Energy Technology Data Exchange (ETDEWEB)

    Heinold, Bernd (Leibniz Inst. for Tropospheric Research, Leipzig (Germany); School of Earth and Environment, Univ. of Leeds, Leeds (United Kingdom)), e-mail: b.heinold@leeds.ac.uk; Tegen, Ina (Leibniz Inst. for Tropospheric Research, Leipzig (Germany)); Bauer, Stefan; Wendisch, Manfred (Leipzig Inst. for Meteorology, Univ. of Leipzig, Leipzig (Germany))

    2011-09-15

    The direct radiative forcing and dynamic atmospheric response due to Saharan dust and biomass-burning aerosol particles are presented for a case study during the SAMUM-2 field campaign in January and February 2008. The regional model system COSMO-MUSCAT is used. It allows online interaction of the computed dust and smoke load with the solar and terrestrial radiation and with the model dynamics. Model results of upward solar irradiances are evaluated against airborne radiation measurements in the Cape Verde region. The comparison shows a good agreement for the case of dust and smoke mixture. Dust and smoke particles influence the atmospheric dynamics by changing the radiative heating rates. The related pressure perturbations modify local and synoptic scale air-flow patterns. In the radiative feedback simulations, the Hadley circulation is enhanced and convergence zones occur along the Guinea coast. Thus, the smoke particles spread more than 5 deg further north and the equatorward transport is reduced. Within the convergence zones, Saharan dust and biomass-burning material are more effectively advected towards the Cape Verdes. Given the model uncertainties, the agreement between the modelled and observed aerosol distribution is locally improved when aerosol-radiation interaction is considered

  6. Uncertainty of dose measurement in radiation processing

    DEFF Research Database (Denmark)

    Miller, A.

    1996-01-01

    The major standard organizations of the world have addressed the issue of reporting uncertainties in measurement reports and certificates. There is, however, still some ambiguity in the minds of many people who try to implement the recommendations in real life. This paper is a contribution...... that contribute to the observable uncertainty of repeated measurements and those that do not. Examples of the use of these principles are presented in the paper....... to the running debate and presents the author's view, which is based upon experience in radiation processing dosimetry. The origin of all uncertainty components must be identified and can be classified according to Type A and Type B, but it is equally important to separate the uncertainty components into those...

  7. MAX-DOAS measurements of atmospheric trace gases in Ny-Ålesund

    Science.gov (United States)

    Wittrock, F.; Oetjen, H.; Richter, A.; Fietkau, S.; Medeke, T.; Rozanov, A.; Burrows, J. P.

    2003-12-01

    A new approach to derive tropospheric concentrations of some atmospheric trace gases from ground-based UV/vis measurements is described. The instrument, referred to as the MAX-DOAS, is based on the well-known UV/vis instruments, which use the sunlight scattered in the zenith sky as the light source and the method of Differential Optical Absorption Spectroscopy (DOAS) to derive column amounts of absorbers like ozone and nitrogen dioxide. Substantial enhancements have been applied to this standard setup to use different lines of sight near to the horizon as additional light sources (MAX - multi axis). Results from measurements at Ny-Ålesund (79° N, 12° E) are presented and interpreted with the full-spherical radiation transport model SCIATRAN. In particular, measurements of the oxygen dimer O4 which has a known column and vertical distribution in the atmosphere are used to evaluate the sensitivity of the retrieval to parameters such as multiple scattering, solar azimuth, surface albedo and refraction in the atmosphere and also to validate the radiative transport model. As a first application, measurements of NO2 emissions from a ship lying in Ny-Ålesund harbour are presented. The results of this study demonstrate the feasibility of long term UV/vis multi axis measurement that can be used to derive not only column amounts of different trace gases but also some information on the vertical location of these absorbers.

  8. Dependence of biologically active UV radiation on the atmospheric ozone in 2000 - 2001 over Stara Zagora, Bulgaria

    International Nuclear Information System (INIS)

    This study investigates how the changes in simultaneously measured ozone columns influence the biologically active UV irradiance. Spectral ground-based measurements of direct solar ultraviolet radiation performed at Stara Zagora (42oN, 25oE), Bulgaria in 2000 - 2001 are used in conjunction with the total ozone content to investigate the relation to the biologically active UV radiation, depending on the solar zenith angle (SZA) and the ozone. The device measures the direct solar radiation in the range 290 - 360 nm at 1 nm resolution. The direct sun UV doses for some specific biological effects (erythema and eyes) are obtained as the integral in the wavelength interval between 290 and 330 nm of the UV solar spectrum weighted with an action spectrum, typical of each effect. For estimation of the sensitivity of biological doses to the atmospheric ozone we calculate the radiation amplification factor (RAF) defined as the percentage increase in the column amount of the atmospheric ozone. The biological doses increase significantly with the decrease of the SZA. The doses of SZA=20o are about three times larger than doses at SZA=50o. The RAF derived from our spectral measurements shows an increase of RAF along with the decreasing ozone. For example, the ozone reduction by 1% increases the erythemal dose by about 2%. (authors)

  9. Stable isotope measurement techniques for atmospheric greenhouse gases

    International Nuclear Information System (INIS)

    The technical requirements to perform useful measurements of atmospheric greenhouse gas concentrations and of their isotope ratios are of direct relevance for all laboratories engaged in this field. A meaningful interpretation of isotopes in global models on sources and sinks of CO2 and other greenhouse gases depends on strict laboratory protocols and data quality control measures ensuring comparable data in time and space. Only with this precondition met, the isotope techniques can serve as a potentially powerful method for reducing uncertainties in the global CO2 budgets and for tracing pathways and interaction of terrestrial, oceanic, and atmospheric pools of carbon. This publication provides four contributions describing methods for the determination of the isotopic composition of trace gases in atmospheric air and in ice cores. These contributions have been indexed separately

  10. Atmospheric Measurements by the Geoscience Laser Altimeter System: Initial Results

    Science.gov (United States)

    Spinhirne, J. D.; Palm, S. P.; Hlavka, D. L.; Hart, W. D.; Mahesh, A.; Welton, E. J.

    2003-01-01

    The Geoscience Laser Altimeter System launched in early 2003 is the first satellite instrument in space to globally observe the distribution of clouds and aerosol through laser remote sensing. The instrument is a basic backscatter lidar that operates at two wavelengths, 532 and 1064 nm. The mission data products for atmospheric observations include the calibrated, observed, attenuated backscatter cross section for cloud and aerosol; height detection for multiple cloud layers; planetary boundary layer height; cirrus and aerosol optical depth and the height distribution of aerosol and cloud scattering cross section profiles. The data is expected to significantly enhance knowledge in several areas of atmospheric science, in particular the distribution, transport and influence of atmospheric aerosol. Measurements of the coverage and height of polar and cirrus cloud should be significantly more accurate than previous global measurement. Initial result from the first several months of operation will be presented.

  11. A microwave pressure sounder. [for remote measurement of atmospheric pressure

    Science.gov (United States)

    Peckham, G. E.; Flower, D. A.

    1981-01-01

    A technique for the remote measurement of atmospheric surface pressure will be described. Such measurements could be made from a satellite in polar orbit and would cover many areas for which conventional meteorological data are not available. An active microwave instrument is used to measure the strength of return echoes from the ocean surface at a number of frequencies near the 60 GHz oxygen absorption band. Factors which affect the accuracy with which surface pressure can be deduced from these measurements will be discussed and an instrument designed to test the method by making measurements from an aircraft will be described.

  12. Some questions about the Venus atmosphere from past measurements

    Science.gov (United States)

    Limaye, Sanjay

    2015-11-01

    The many missions undertaken in the past half a century to explore Venus with fly-by spacecraft, orbiters, descending probes, landers and floating balloons, have provided us with a wealth of data. These data have been supplemented by many ground based observations at reflected solar wavelengths, short and long wave infrared to radio waves. Inter-comparison of the results from such measurements provide a good general idea of the global atmosphere. However, re-visiting these observations also raises some questions about the atmosphere that have not received much attention lately but deserve to be explored and considered for future measurements.These questions are about the precise atmospheric composition in the deep atmosphere, the atmospheric state in the lower atmosphere, the static stability of the lower atmosphere, the clouds and hazes, the nature of the ultraviolet absorber and wind speed and direction near the surface from equator to the pole. The answers to these questions are important for a better understanding of Venus, its weather and climate. The measurements required to answer these questions require careful and sustained observations within the atmosphere and from surface based stations. Some of these measurements should and can be made by large missions such as Venera-D (Russia), Venus Climate Mission (Visions and Voyages - Planetary Science Decadal Survey 2013-2022 or the Venus Flagship Design Reference Mission (NASA) which have been studied in recent years, but some have not been addressed in such studies. For example, the fact that the two primary constituents of the Venus atmosphere - Carbon Dioxide and Nitrogen are supercritical has not been considered so far. It is only recently that properties of binary supercritical fluids are being studied theoretically and laboratory validation is needed.With the end of monitoring of Venus by Venus Express orbiter in November 2014 after nearly a decade of observations and the imminent insertion of JAXA

  13. Effect of atmospheric gases, surface albedo and cloud overlap on the absorbed solar radiation

    Directory of Open Access Journals (Sweden)

    Ashok Sinha

    Full Text Available Recent studies have provided new evidence that models may systematically underestimate cloud solar absorption compared to observations. This study extends previous work on this "absorption anomaly'' by using observational data together with solar radiative transfer parameterisations to calculate fs (the ratio of surface and top of the atmosphere net cloud forcings and its latitudinal variation for a range of cloud types. Principally, it is found that (a the zonal mean behaviour of fs varies substantially with cloud type, with the highest values obtained for low clouds; (b gaseous absorption and scattering can radically alter the pattern of the variation of fs with latitude, but gaseous effects cannot in general raise fs to the level of around 1.5 as recently determined; (c the importance of the gaseous contribution to the atmospheric ASR is such that whilst fs rises with surface albedo, the net cloud contribution to the atmospheric ASR falls; (d the assumed form of the degree of cloud overlap in the model can substantially affect the cloud contribution to the atmospheric ASR whilst leaving the parameter fs largely unaffected; (e even large uncertainties in the observed optical depths alone cannot account for discrepancies apparent between modelled and newly observed cloud solar absorption. It is concluded that the main source of the anomaly may derive from the considerable uncertainties regarding impure droplet microphysics rather than, or together with, uncertainties in macroscopic quantities. Further, variable surface albedos and gaseous effects may limit the use of contemporaneous satellite and ground-based measurements to infer the cloud solar absorption from the parameter fs.

  14. Spatial and Temporal Variability of the Gamma Radiation from Earth's Atmosphere during a Solar Cycle

    CERN Document Server

    Harris, M J; Leising, M D; Harris, Michael J.; Share, Gerald H.; Leising, Mark D.

    2003-01-01

    The Solar Maximum Mission satellite's Gamma Ray Spectrometer observed Earth's atmosphere for most of the period 1980-1989. Its 28deg orbit ensured that a range of geomagnetic latitudes (geomagnetic cutoff rigidities) was sampled. We measured the variation with time and rigidity of albedo gamma-ray lines at 1.6 MeV, 2.3 MeV and 4.4 MeV which are diagnostic of Galactic cosmic radiation penetrating the cutoff and of the secondary neutrons produced in the atmosphere. We found that the gamma-ray line intensities varied inversely with solar activity and cutoff rigidity, as expected. The line ratio (1.6 MeV + 2.3 MeV)/4.4 MeV was remarkably constant (close to 0.39) at all times and rigidities; the former two lines are produced by 5-10 MeV secondary neutrons causing excitation and de-excitation of 14N, while the latter is produced by more energetic (>20 MeV) neutrons inducing spallation. We infer that the shape of the secondary neutron energy spectrum is virtually constant everywhere and at all times. We also measure...

  15. Towards an exploitation of IAGOS atmospheric composition measurements

    Science.gov (United States)

    Marshall, Julia; Gerbig, Christoph; Petzold, Andreas; Zahn, Andreas

    2015-04-01

    IAGOS, In-service Aircraft for a Global Observing System, has installed instrumentation on a growing fleet of commercial airliners in order to continuously monitor atmospheric composition around the globe. IAGOS is providing accurate in situ observations of greenhouse gases (GHGs), reactive gases, aerosols, and cloud particles at high spatial resolution in the free atmosphere, thereby covering the essential climate variables (ECVs) for atmospheric composition as designated by the GCOS programme (Implementation Plan for the Global Observing System for Climate in Support of the UNFCCC, 2010). The greenhouse gas measurements made by IAGOS will be submitted to the WMO/GAW World Data Centre for Greenhouse Gases (WDCGG). Within the EU FP7 project IGAS (IAGOS for the GMES Atmospheric Service), the links between this new data stream and scientific users, including the Copernicus Atmosphere Monitoring Service, are being improved. This includes the provision of measurements in both near-real-time and delayed mode, and improved accessibility to the data through linkages to the databases of both the German Aerospace Centre (DLR) flight campaign archive and the Copernicus data archive. Work has been undertaken to investigate the use of the near-real-time profile measurements in order to correct bias in satellite measurements assimilated by the Copernicus Atmosphere Monitoring Service. Documentation of the QA/QC procedures and measurement techniques for each instrument have been formalized and reviewed by external experts, to provide users with a measurement traceable to WMO standards. The representativeness of the measurements has been assessed, to better interpret results in polluted regions and near the tropopause. The potential impact of the GHG measurements on regional scale flux inversions has been quantified, which is relevant for ICOS (Integrated Carbon Observing System). Finally, tools have been developed to use the measurements for validation of satellite column

  16. The role of atmospheric radiation in the generation and maintenance of circulations of different scales

    International Nuclear Information System (INIS)

    It is well known that the radiation budget of the atmosphere is an important component of the earth's climate system. On shorter time scales, radiative transfer affects the evolution of atmospheric circulation, principally through interaction with cloud and storm systems, and destabilizes the atmosphere continuously. This destabilization is important for subsequent development of clouds and storm systems. The clouds and storm systems feed back to the radiation budget, as clouds significantly alter both shortwave and longwave radiative transfer. It is important to understand the role that radiative transfer plays in the evolution of these circulation systems to accurately quantify the radiation budget. The results presented here are from modeling studies designed to isolate the effect of radiative transfer on the generation of circulation systems of different spatial and temporal scales. Two different numerical weather prediction models were used and will be described briefly in the next section. Following that, the radiative transfer model that was used with both circulation models will be described. Finally, results from the modeling studies will be presented, and conclusions and future research efforts will be discussed

  17. Greenhouse gases regional fluxes estimated from atmospheric measurements

    International Nuclear Information System (INIS)

    build up a new system to measure continuously CO2 (or CO), CH4, N2O and SF6 mixing ratios. It is based on a commercial gas chromatograph (Agilent 6890N) which have been modified to reach better precision. Reproducibility computed with a target gas on a 24 hours time step gives: 0.06 ppm for CO2, 1.4 ppb for CO, 0.7 ppb for CH4, 0.2 ppb for N2O and 0.05 ppt for SF6. The instrument's run is fully automated, an air sample analysis takes about 5 minutes. In July 2006, I install instrumentation on a telecommunication tall tower (200 m) situated near Orleans forest in Trainou, to monitor continuously greenhouse gases (CO2, CH4, N2O, SF6), atmospheric tracers (CO, Radon-222) and meteorological parameters. Intake lines were installed at 3 levels (50, 100 and 180 m) and allow us to sample air masses along the vertical. Continuous measurement started in January 2007. I used Mace Head (Ireland) and Gif-sur-Yvette continuous measurements to estimate major greenhouse gases emission fluxes at regional scale. To make the link between atmospheric measurements and surface fluxes, we need to quantify dilution due to atmospheric transport. I used Radon-222 as tracer (radon tracer method) and planetary boundary layer heights estimates from ECMWF model (boundary layer budget method) to parameterize atmospheric transport. In both cases I compared results to available emission inventories. (author)

  18. Measurement of atmospheric neutrino oscillations with the ANTARES neutrino telescope

    NARCIS (Netherlands)

    S. Adrián-Martínez; . et al.; M.P. Decowski; P. Kooijman; G. Lim; D. Palioselitis; E. Presani; E. de Wolf

    2012-01-01

    The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoi

  19. Determination of atmospheric aerosol properties over land using satellite measurements

    NARCIS (Netherlands)

    Kokhanovsky, A.A.; Leeuw, G. de

    2009-01-01

    Mostly, aerosol properties are poorly understood because the aerosol properties are very sparse. The first workshop on the determination of atmospheric aerosol properties over land using satellite measurements is convened in Bremen, Germany. In this workshop, the topics of discussions included a var

  20. Final Report - From Measurements to Models: Cross-Comparison of Measured and Simulated Behavioral States of the Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Del Genio, Anthony D; Hoffman, Forrest M; Hargrove, Jr, William W

    2007-10-22

    The ARM sites and the ARM Mobile Facility (AMF) were constructed to make measurements of the atmosphere and radiation system in order to quantify deficiencies in the simulation of clouds within models and to make improvements in those models. While the measurement infrastructure of ARM is well-developed and a model parameterization testbed capability has been established, additional effort is needed to develop statistical techniques which permit the comparison of simulation output from atmospheric models with actual measurements. Our project establishes a new methodology for objectively comparing ARM measurements to the outputs of leading global climate models and reanalysis data. The quantitative basis for this comparison is provided by a statistical procedure which establishes an exhaustive set of mutually-exclusive, recurring states of the atmosphere from sets of multivariate atmospheric and cloud conditions, and then classifies multivariate measurements or simulation outputs into those states. Whether measurements and models classify the atmosphere into the same states at specific locations through time provides an unequivocal comparison result. Times and locations in both geographic and state space of model-measurement agreement and disagreement will suggest directions for the collection of additional measurements at existing sites, provide insight into the global representativeness of the current ARM sites (suggesting locations and times for use of the AMF), and provide a basis for improvement of models. Two different analyses were conducted: One, using the Parallel Climate Model, focused on an IPCC climate change scenario and clusters that characterize long-term changes in the hydrologic cycle. The other, using the GISS Model E GCM and the ARM Active Remotely Sensed Cloud Layers product, explored current climate cloud regimes in the Tropical West Pacific.

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

    Science.gov (United States)

    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.

  2. Study and measurement of the atmospheric pollution by 85Kr

    International Nuclear Information System (INIS)

    Because of the importance of eventual long term radiological and synergistic effects of 85Kr pollution from the nuclear energy industry the atmospheric activity was followed and laboratory experiments on the initiation of eventual climatological effects were developed. An EPA method for separating krypton from air and for measuring the radioactivity was applied. The modified experimental set-up for collection, separation and measurement is illustrated. The total collection and separation efficiency is about 55%. The efficiency of the nuclear β-measurement was found to be 72% using a calibrated source. The results of periodic atmospheric measurements in Ghent during 1979 are reported. Comparative calculations based on available source terms are presented. (H.K.)

  3. Condition of Retrieving Vertical Column Density of Atmospheric Pollution Gases by Using Scattered Solar Radiation

    Institute of Scientific and Technical Information of China (English)

    ZUO Sao-Yi

    2009-01-01

    We present a method to monitor the vertical column density (VCD) of atmospheric pollution gases by using the scattered solar radiation. The necessary condition of capturing the useful scattered solar radiation is achieved. The condition is only dependent on the solar elevation angle, while independent of the solar azimuth angle, which could greatly simply the capturing equipment and procedure. Under the condition, the VCD of tropospheric NO2 in Chengdu, China is retrieved from the scattered solar radiation, which is dose to that from the direct solar radiation.

  4. Atmospheric mercury measurements onboard the CARIBIC passenger aircraft

    Science.gov (United States)

    Slemr, Franz; Weigelt, Andreas; Ebinghaus, Ralf; Kock, Hans H.; Bödewadt, Jan; Brenninkmeijer, Carl A. M.; Rauthe-Schöch, Armin; Weber, Stefan; Hermann, Markus; Becker, Julia; Zahn, Andreas; Martinsson, Bengt

    2016-05-01

    Goal of the project CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrumented Container) is to carry out regular and detailed observations of atmospheric composition (particles and gases) at cruising altitudes of passenger aircraft, i.e. at 9-12 km. Mercury has been measured since May 2005 by a modified Tekran instrument (Tekran Model 2537 A analyser, Tekran Inc., Toronto, Canada) during monthly intercontinental flights between Europe and South and North America, Africa, and Asia. Here we describe the instrument modifications, the post-flight processing of the raw instrument signal, and the fractionation experiments.

  5. Radiation Measurements in the Decommissioning of a Rare Earth Plant

    Institute of Scientific and Technical Information of China (English)

    WANG; Shao-lin

    2012-01-01

    <正>Radiation measurement including radiological source term investigation before the decommissioning, supervisory monitoring during the decommissioning and termination survey after the decommissioning of a rare earth plant were implemented successfully by Radiation Monitoring and Assessment Research Section, Department of Radiation Safety, China Institute of Atomic Energy. The measurements were started in July 2009 and finished in the end of April 2010.

  6. Status of Radiative Transfer Model (RTM) development for the Northrop Grumman Venus Atmospheric Maneuverable Platform (VAMP) Technology Development Program

    Science.gov (United States)

    Wong, Eric

    2014-11-01

    In support of the Northrop Grumman/L-Garde Venus Atmospheric Maneuverable Platform (VAMP) development, we are developing a multi-purpose radiative transfer model (RTM) for the applications of the Venus atmosphere. For the solar array sizing, spectral solar radiance calculations are needed and a Correlated-k method of spectral integration will be used. This method is relatively fast computationally and typical error of the method is within a few percent, sufficiently accurate for solar array sizing analyses. For sensor characterization or sensor performance study, details of an absorption line, e.g. the near-IR “atmospheric window” absorption lines, must be used and an equivalent line-by-line calculation will be performed. At the completion of the model a large data base of radiance profiles of different atmospheric conditions will be created. The database can also be used to support thermal radiation analysis for other sub-systems. In this poster, we present our current state of the RTM development and model validation development. Additionally, we will present some preliminary comparison of top-of-atmosphere solar radiance with Venus Express VIRTIS measurements.

  7. Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion

    Directory of Open Access Journals (Sweden)

    S. J. Solomon

    2005-05-01

    Full Text Available A novel atmospheric methanol measurement technique, employing selective gas-phase catalytic conversion of methanol to formaldehyde followed by detection of the formaldehyde product, has been developed and tested. The effects of temperature, gas flow rate, gas composition, reactor-bed length, and reactor-bed composition on the methanol conversion efficiency of a molybdenum-rich, iron-molybdate catalyst [Mo-Fe-O] were studied. Best results were achieved using a 1:4 mixture (w/w of the catalyst in quartz sand. Optimal methanol to formaldehyde conversion (>95% efficiency occurred at a catalyst housing temperature of 345°C and an estimated sample-air/catalyst contact time of <0.2 s. Potential interferences arising from conversion of methane and a number of common volatile organic compounds (VOC to formaldehyde were found to be negligible under most atmospheric conditions and catalyst housing temperatures. Using the new technique, atmospheric measurements of methanol were made at the University of Bremen campus from 1 to 15 July 2004. Methanol mixing ratios ranged from 1 to 5 ppb with distinct maxima at night. Formaldehyde mixing ratios, obtained in conjunction with methanol by periodically bypassing the catalytic converter, ranged from 0.2 to 1.6 ppb with maxima during midday. These results suggest that selective, catalytic methanol to formaldehyde conversion, coupled with existing formaldehyde measurement instrumentation, is an inexpensive and effective means for monitoring atmospheric methanol.

  8. Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion

    Directory of Open Access Journals (Sweden)

    S. J. Solomon

    2005-01-01

    Full Text Available A novel atmospheric methanol measurement technique, employing selective gas-phase catalytic conversion of methanol to formaldehyde followed by detection of the formaldehyde product, has been developed and tested. The effects of temperature, gas flow rate, gas composition, reactor-bed length, and reactor-bed composition on the methanol conversion efficiency of a molybdenum-rich, iron-molybdate catalyst [Mo-Fe-O] were studied. Best results were achieved using a 1:4 mixture (w/w of the catalyst in quartz sand. Optimal methanol to formaldehyde conversion (>95% efficiency occurred at a catalyst housing temperature of 345°C and an estimated sample-air/catalyst contact time of <0.2 seconds. Potential interferences arising from conversion of methane and a number of common volatile organic compounds (VOC to formaldehyde were found to be negligible under most atmospheric conditions and catalyst housing temperatures. Using the new technique, atmospheric measurements of methanol were made at the University of Bremen campus from 1 to 15 July 2004. Methanol mixing ratios ranged from 1 to 5 ppb with distinct maxima at night. Formaldehyde mixing ratios, obtained in conjunction with methanol by periodically bypassing the catalytic converter, ranged from 0.2 to 1.6 ppb with maxima during midday. These results suggest that selective, catalytic methanol to formaldehyde conversion, coupled with existing formaldehyde measurement instrumentation, is an inexpensive and effective means for monitoring atmospheric methanol.

  9. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    Science.gov (United States)

    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

  10. Visualization of Radiation Environment on Mars: Assessment with MARIE Measurements

    Science.gov (United States)

    Saganti, P.; Cucinotta, F.; Zeitlin, C.; Cleghorn, T.; Flanders, J.; Riman, F.; Hu, X.; Pinsky, L.; Lee, K.; Anderson, V.; Atwell, W.; Turner, R.

    2003-01-01

    For a given GCR (Galactic Cosmic Ray) environment at Mars, particle flux of protons, alpha particles, and heavy ions, are also needed on the surface of Mars for future human exploration missions. For the past twelve months, the MARJE (Martian Radiation Environment Experiment) instrument onboard the 200J Mars Odyssey has been providing the radiation measurements from the Martian orbit. These measurements are well correlated with the HZETRN (High Z and Energy Transport) and QMSFRG (Quantum Multiple-Scattering theory of nuclear Fragmentation) model calculations. These model calculations during these specific GCR environment conditions are now extended and transported through the CO2 atmosphere onto the Martian surface. These calculated pa11icle flux distributions are presented as a function of the Martian topography making use of the MOLA (Mars Orbiter Laser Altimeter) data from the MGS (Mars Global Surveyor). Also, particle flux calculations are presented with visualization in the human body from skin depth to the internal organs including the blood-forming organs.

  11. Visualization of radiation environment on Mars: assessment with MARIE measurements

    International Nuclear Information System (INIS)

    Full text: For a given GCR (Galactic Cosmic Ray) environment at Mars, particle flux of protons, alpha particles, and heavy ions, are also needed on the surface of Mars for future human exploration missions. For the past twelve months, the MARIE (Martian Radiation Environment Experiment) instrument onboard the 2001 Mars Odyssey has been providing the radiation measurements from the Martian orbit. These measurements are well correlated with the HZETRN (High Z and Energy Transport) and QMSFRG (Quantum Multiple-Scattering theory of nuclear Fragmentation) model calculations. These model calculations during these specific GCR environment conditions are now extended and transported through the CO2 atmosphere onto the Martian surface. These calculated particle flux distributions are presented as a function of the Martian topography making use of the MOLA (Mars Orbiter Laser Altimeter) data from the MGS (Mars Global Surveyor). Also, particle flux calculations are presented with visualization in the human body from skin depth to the internal organs including the blood-forming organs

  12. Atmospheric stability and complex terrain: comparing measurements and CFD

    DEFF Research Database (Denmark)

    Koblitz, Tilman; Bechmann, Andreas; Berg, Jacob;

    2014-01-01

    For wind resource assessment, the wind industry is increasingly relying on Computational Fluid Dynamics models that focus on modeling the airflow in a neutrally stratified surface layer. So far, physical processes that are specific to the atmospheric boundary layer, for example the Coriolis force......-neutral atmospheric flow over complex terrain including physical processes like stability and Coriolis force. We examine the influence of these effects on the whole atmospheric boundary layer using the DTU Wind Energy flow solver EllipSys3D. To validate the flow solver, measurements from Benakanahalli hill, a field...... experiment that took place in India in early 2010, are used. The experiment was specifically designed to address the combined effects of stability and Coriolis force over complex terrain, and provides a dataset to validate flow solvers. Including those effects into EllipSys3D significantly improves...

  13. Measurement of the dynamic characteristics of atmospheric diffusion

    International Nuclear Information System (INIS)

    A new method is proposed for studying the diffusion of atmospheric pollutants above real sites which considers the actual magnitudes encountered. The dynamic application of this method yields original information. In view of justifying the method, fundamental theories concerning diffusion are presented together with different models for the atmosphere. The atmosphere is then considered as a linear filter to which the process identification method is applied. The pulse response of the filter is examined in the pollutant - time plane. The limits of the method and its field of application are discussed. The concept of ergodism and stationariness are introduced. Various diffusion experiments carried out under different conditions are reviewed. Information on the effect of obstacles, and the roughness of the ground is given together with calculations of the longitudinal diffusion and the transport velocity. A brief description is then given of the apparatus used to measure the concentrations and the meteorological conditions. The correlation calculation is also briefly presented. (author)

  14. A new model on bidirectional reflectance surface-atmospheric coupled radiation

    Institute of Scientific and Technical Information of China (English)

    QIU; Jinhuan; (邱金桓)

    2001-01-01

    An exact and available model on bidirectional reflectance surface-atmospheric coupled radiation is of great significance for spaceborne remote sensing application. Based on the physical process of interaction of solar radiation with the surface and the atmosphere, a new model on bidirectional reflectance surface-atmospheric coupled radiation is developed in this paper. As shown in numerical simulation, this model is evidently better than the 6S model. The standard error among 110112 sets of upward radiance data calculated by this new model is only 0.49%, which is about one fourth of the one by 6S. In the condition of the solar zenith angle qs≤75°and the viewing angle qv≤60°, the error by the new model is usually smaller than 2.5%.

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

    CERN Document Server

    Aplin, K L

    2012-01-01

    Cosmic rays produce charged molecular clusters by ionisation as they pass through the lower atmosphere. Neutral molecular clusters such as dimers and complexes are expected to make a small contribution to the radiative balance, but atmospheric absorption by charged clusters has not hitherto been observed. In an atmospheric experiment, a filter radiometer tuned to the 9.15 um absorption band associated with infra-red absorption of charged molecular clusters was used to monitor changes immediately following events identified by a cosmic ray telescope sensitive to high energy (>400MeV) particles, principally muons. The change in longwave radiation in this absorption band due to charged molecular clusters is 7 mW^m-2. The integrated atmospheric energy change for each event is 2J, representing an amplification factor of 10^10 compared to the 2GeV energy of a typical tropospheric cosmic ray. This absorption is expected to occur continuously and globally.

  16. Impact of uncertainties in atmospheric mixing on simulated UTLS composition and related radiative effects

    OpenAIRE

    Riese, Martin; Ploeger, F; Rap, A.; B. Vogel; P. Konopka; Dameris, Martin; Forster, P

    2012-01-01

    The upper troposphere/lower stratosphere (UTLS) region plays an important role in the climate system. Changes in the structure and chemical composition of this region result in particularly large changes in radiative forcings of the atmosphere. Quantifying the processes that control UTLS composition (e.g., stratosphere-troposphere exchange) therefore represents a crucial task. We assess the influence of uncertainties in the atmospheric mixing strength on global UTLS distributions of greenh...

  17. Atmospheric Sulfur Hexafluoride: Measurements and Emission Estimates from 1970 - 2008

    Science.gov (United States)

    Rigby, M. L.; Prinn, R. G.; Muhle, J.; Miller, B. R.; Dlugokencky, E. J.; Krummel, P. B.; Steele, L. P.; Fraser, P. J.; Leist, M.; Weiss, R. F.; Harth, C. M.; O'Doherty, S. J.; Greally, B. R.; Simmonds, P. G.; Derek, N.; Vollmer, M. K.; Kim, J.; Kim, K.; Porter, L. W.

    2009-12-01

    We present an air history of atmospheric sulfur hexafluoride (SF6) from the early 1970s through 2008. During this period, concentrations of this extremely potent and long-lived greenhouse gas have increased by more than an order of magnitude, and its growth has accelerated in recent years. In this study, historical concentrations are determined from archived air samples measured on the Advanced Global Atmospheric Gases Experiment (AGAGE) ‘Medusa’ gas chromatography/mass spectrometry system. These data are combined with modern high-frequency measurements from the AGAGE and National Oceanic and Atmospheric Administration (NOAA) in situ networks and ˜weekly samples from the NOAA flask network, to produce a unique time series with increasing global coverage spanning almost four decades. Using the three-dimensional chemical transport Model for Ozone and Related Tracers (MOZART v4.5) and a discrete Kalman filter, we derive estimates of the annual emission strength of SF6 on hemispheric scales from 1970 - 2004 and on continental scales from 2004 - 2008. Our emission estimates are compared to the recently compiled Emissions Database for Global Atmospheric Research (EDGAR v4), and emissions reported under the United Nations Framework Convention on Climate Change (UNFCCC). The cause of the recent growth rate increase is also investigated, indicating that the origin of the required emissions rise is likely to be South-East Asia.

  18. Atmospheric circulation of tidally locked exoplanets II: dual-band radiative transfer and convective adjustment

    CERN Document Server

    Heng, Kevin; Phillipps, Peter J

    2011-01-01

    Improving upon our purely dynamical work, we present three-dimensional simulations of the atmospheric circulation on Earth-like (exo)planets and hot Jupiters using the GFDL-Princeton Flexible Modeling System (FMS). As the first steps away from the purely dynamical benchmarks of Heng, Menou & Phillipps (2011), we add dual-band radiative transfer and dry convective adjustment schemes to our computational setup. Our treatment of radiative transfer assumes stellar irradiation to peak at a wavelength shorter than and distinct from that at which the exoplanet re-emits radiation ("shortwave" versus "longwave"), and also uses a two-stream approximation. Convection is mimicked by adjusting unstable lapse rates to the dry adiabat. The bottom of the atmosphere is bounded by an uniform slab with a finite thermal inertia. For our hot Jupiter models, we include an analytical formalism for calculating temperature-pressure profiles, in radiative equilibrium, which accounts for the effect of collision-induced absorption v...

  19. he Impact of Primary Marine Aerosol on Atmospheric Chemistry, Radiation and Climate: A CCSM Model Development Study

    Energy Technology Data Exchange (ETDEWEB)

    Keene, William C. [University of Virginia; Long, Michael S. [University of Virginia

    2013-05-20

    This project examined the potential large-scale influence of marine aerosol cycling on atmospheric chemistry, physics and radiative transfer. Measurements indicate that the size-dependent generation of marine aerosols by wind waves at the ocean surface and the subsequent production and cycling of halogen-radicals are important but poorly constrained processes that influence climate regionally and globally. A reliable capacity to examine the role of marine aerosol in the global-scale atmospheric system requires that the important size-resolved chemical processes be treated explicitly. But the treatment of multiphase chemistry across the breadth of chemical scenarios encountered throughout the atmosphere is sensitive to the initial conditions and the precision of the solution method. This study examined this sensitivity, constrained it using high-resolution laboratory and field measurements, and deployed it in a coupled chemical-microphysical 3-D atmosphere model. First, laboratory measurements of fresh, unreacted marine aerosol were used to formulate a sea-state based marine aerosol source parameterization that captured the initial organic, inorganic, and physical conditions of the aerosol population. Second, a multiphase chemical mechanism, solved using the Max Planck Institute for Chemistry's MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) system, was benchmarked across a broad set of observed chemical and physical conditions in the marine atmosphere. Using these results, the mechanism was systematically reduced to maximize computational speed. Finally, the mechanism was coupled to the 3-mode modal aerosol version of the NCAR Community Atmosphere Model (CAM v3.6.33). Decadal-scale simulations with CAM v.3.6.33, were run both with and without reactive-halogen chemistry and with and without explicit treatment of particulate organic carbon in the marine aerosol source function. Simulated results were interpreted (1) to evaluate influences

  20. Cloud and Radiation Processes Simulated by a Coupled Atmosphere-Ocean Model

    Institute of Scientific and Technical Information of China (English)

    WANG Fang; DING Yihui; XU Ying

    2007-01-01

    Using NCC/IAP T63 coupled atmosphere-ocean general circulation model (AOGCM), two 20-yr integrations were processed, and their ability to simulate cloud and radiation was analysed in detail. The results show that the model can simulate the basic distribution of cloud cover, and however, obvious differences still exist compared with ISCCP satellite data and ERA reanalysis data. The simulated cloud cover is less in general, especially the abnormal low values in some regions of ocean. By improving the cloud cover scheme,simulated cloud cover in the eastern Pacific and Atlantic, summer hemisphere's oceans from subtropical to mid-latitude is considerably improved. But in the tropical Indian Ocean and West Pacific the cloud cover difference is still evident, mainly due to the deficiency of high cloud simulation in these regions resulting from deep cumulus convection. In terms of the analysis on radiation and cloud radiative forcing, we find that simulation on long wave radiation is better than short wave radiation. The simulation error of short wave radiation is caused mostly by the simulation difference in short wave radiative forcing, sea ice, and snow cover, and also by not involving aerosol's effect. The simulation error of long wave radiation is mainly resulting from deficiency in simulating cloud cover and underlying surface temperature. Corresponding to improvement of cloud cover, the simulated radiation (especially short wave radiation) in eastern oceans,summer hemisphere's oceans from subtropical to mid-latitude is remarkably improved. This also bring sobvious improvement to net radiation in these regions.

  1. Direct measurements of the effect of biomass burning over the Amazon on the atmospheric temperature profile

    Directory of Open Access Journals (Sweden)

    L. Remer

    2009-11-01

    Full Text Available Aerosols suspended in the atmosphere interact with solar radiation and clouds, thus change the radiation energy fluxes in the atmospheric column. In this paper we measure changes in the atmospheric temperature profile as a function of the smoke loading and the cloudiness, over the Amazon basin, during the dry seasons (August and September of 2005–2008. We show that as the aerosol optical depth (AOD increases from 0.02 to a value of ~0.6, there is a decrease of ~4°C at 1000 hPa, and an increase of ~1.5°C at 850 hPa. The warming of the aerosol layer at 850 hPa is likely due to aerosol absorption when the particles are exposed to direct illumination by the sun. The large values of cooling in the lower layers could be explained by a combination of aerosol extinction of the solar flux in the layers aloft together with an aerosol-induced increase of cloud cover which shade the lower atmosphere. We estimate that the increase in cloud fraction due to aerosol contributes about half of the observed cooling in the lower layers.

  2. Microdosimetric measurements for radiotherapy and radiation protection

    International Nuclear Information System (INIS)

    Neutrons produced by bombarding a 4 mm thick beryllium target with deuterons of 30 MeV and 70 MeV proton beams are used for a clinical trials of radiotherapy in NIRS cyclotron facility. Microdosimetric measurements for neutrons and protons were carried out using a tissue-equivalent (TE) proportional counters, and LET-1/2-SW counter and LET-5-SW counter. The TE gas employed is the propane based mixture, and pressure of 67.7 torr provided an effective sphere diameter of 2 μm for LET-1/2-SW counter. Alpha particles emitted from Cm-244 have an energy of approximatey 5.8 MeV, and the energy loss in a 2 μm path length of propane based TE gas was calculated to be 79.2 keV/μm. For the improvement of S/N ratio, a probetype charge sensitive pre-amplifier built in a first stage FET was used. Electronic signals were amplified and processed with a homemade spectroscopy logarithmic amplifier and a multichannel analyzer. The logarithmic amplifier made it possible to measure the dose distributions in lineal energy from less than 50 eV/μm to 2000 keV/μm at the same time. The number of pulse as a function of lineal energy in logarithm was stored and then processed with a personal computer (PC-9801). The measurement were also made on mixed radiation fields of neutron and proton and gamma-rays in order to investigate the variation of dose distribution in lineal energy. The differential distribution of dose in lineal energy, d(y) = y·n(y) was normalized to yield the fraction of dose deposited per unit of lineal energy. On the basis of these distributions, the dose-averaged LET and the average quality factor for radiations outside the primary beams was determined by using calculated with separately d(y)-distribution of a Photon fields. (author)

  3. Gamma radiation measurements in Brazilian commercial granites

    Energy Technology Data Exchange (ETDEWEB)

    Anjos, R.M.; Veiga, R.; Mosquera, B.; Carvalho, C.; Macario, K. [Universidade Federal Fluminense, Niteroi (Brazil)

    2006-07-01

    Full text of publication follows: Gamma radiation from radionuclides which are characterized by half lives comparable to the age of the earth, such as 40 K and the radionuclides from the 238 U and 232 Th series, and their decay products, represent the main terrestrial source of irradiation to the human body. Their concentrations vary for different types of rocks, where high radiation levels are associated with igneous rocks such as granite. Thorium, uranium and potassium concentrations of granitic rocks are intimately related to their mineral compositions and general petrologic features. Then, these features associated with effects of weathering and metamorphism produce expressive alterations in the relationship between the natural radionuclides (Th, U, K, Th/U and Th/K). Consequently, the measurements of thorium, uranium, and potassium concentrations of different granite samples result on individual differentiation sequences. From the 232 Th, 238 U and 40 K activity concentrations obtained for each sample, it is possible to evaluate their respective dose rates in air, when these stones are used as tiling rocks. These results are of great interest in the environmental radiological protection study, since granites are widely used as building and ornamental materials, including as indoor covering. In this way, the Laboratory of Radioecology (L.A.R.A.) of the Physics Institute of the Universidade Federal Fluminense (I.F. -U.F.F.) has been performing analyzes on more than one hundred differ ent types of the main Brazilian commercial granites in last two years [1]. Using NaI and HP Ge gamma-ray spectrometers to determine the concentration of natural radionuclides in these samples, the annual effective dose rates and the gamma activity concentration index have been evaluated and compared to the limits proposed by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and European Commission (E.C.). In addition, the correlations between thorium

  4. A Thermal Infrared Radiation Parameterization for Atmospheric Studies

    Science.gov (United States)

    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.

  5. Research on atmospheric corrosion of steel using synchrotron radiation

    International Nuclear Information System (INIS)

    Correlation between local structure around Cr in the protective rust layer on weathering steel and protective performance of the rust layer is presented as an example of corrosion research using synchrotron radiation which has recently been applied in various research fields as a useful tool. In addition, in situ observation of initial process of rust formation on steel is also mentioned. It was pointed out by considering the X-ray absorption fine structure spectra that the nanostructure of the protective rust layer on weathering steel primarily comprises of small Cr-goethite crystals containing surface adsorbed and/or intergranular CrOx3-2X complex anions. This CrOx3-2X explains the protective performance of the rust layer originated by dense aggregation of fine crystals with cation selectivity of the Cr-goethite. It is very advantageous to employ white X-rays for in situ observation of rusting process of a carbon steel covered with electrolyte thin films because rust structure might change very quickly. This in situ observation revealed the effect of ion species on the change in rust phase during wet/dry repeating. It can be said that application of synchrotron radiation on corrosion research is so useful to understand the nanostructure of surface oxides which closely relate to corrosion behavior of metals and alloys. (author)

  6. An atmospheric radiative-convective model with interactive water vapor transport and cloud development

    OpenAIRE

    HUMMEL, JOHN R.; KUHN, WILLIAM R.

    2011-01-01

    In the present generation of radiative-convective models, clouds are assigned specific levels or temperatures that do not change during the course of the calculations. In addition, a single water vapor distribution is used for the “mean atmosphere” instead of separate distributions for the clear sky and cloudy sky atmospheres. We present results from a one-dimensional radiative-convective model that includes interactive water vapor transport and predicts cloud altitudes and thicknesses. The ...

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

    OpenAIRE

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

    2016-01-01

    The influence of reduced solar forcing (grand solar minimum or geoengineering scenarios like solar radiation management) on the Atlantic meridional overturning circulation (AMOC) is assessed in an ensemble of atmosphere-ocean-chemistry-climate model simulations. Ensemble sensitivity simulations are performed with and without interactive chemistry. Without chemistry-climate interaction the AMOC is intensified in the course of the solar radiation reduction (SRR), which is ...

  8. Continuous measurements of greenhouse gases and atmospheric oxygen at the Namib Desert Atmospheric Observatory

    OpenAIRE

    E. J. Morgan; J. V. Lavrič; Seifert, T.; T. Chicoine; Day, A; J. Gomez; Logan, R. (Robert); Sack, J.; Shuuya, T.; E. G. Uushona; K. Vincent; Schultz, U.; E.-G. Brunke; C. Labuschagne; Thompson, R. L.

    2015-01-01

    A new coastal background site has been established for observations of greenhouse gases (GHGs) in the central Namib Desert at Gobabeb, Namibia. The location of the site was chosen to provide observations for a data-poor region in the global sampling network for GHGs. Semi-automated, continuous measurements of carbon dioxide, methane, nitrous oxide, carbon monoxide, atmospheric oxygen, and basic meteorology are made at a height of 21 m a.g....

  9. Radiation detection and measurement concepts, methods and devices

    CERN Document Server

    McGregor, Douglas

    2017-01-01

    This text on radiation detection and measurement is a response to numerous requests expressed by students at various universities, in which the most popularly used books do not provide adequate background material, nor explain matters in understandable terms. This work provides a modern overview of radiation detection devices and radiation measurement methods. The topics selected in the book have been selected on the basis of the author’s many years of experience designing radiation detectors and teaching radiation detection and measurement in a classroom environment.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Measurement of Atmospheric Neutrino Oscillations with the ANTARES Neutrino Telescope

    CERN Document Server

    Adrian-Martinez, S; Albert, A; Andre, M; Anghinolfi, M; Anton, G; Anvar, S; Ardid, M; Astraatmadja, T; Aubert, J -J; Baret, B; Basa, S; Bertin, V; Biagi, S; Bigongiari, C; Bogazzi, C; Bou-Cabo, M; Bouhou, B; Bouwhuis, M C; Brunner, J; Busto, J; Capone, A; Carloganu, C; Carr, J; Cecchini, S; Charif, Z; Charvis, Ph; Chiarusi, T; Circella, M; Coniglione, R; Core, L; Costantini, H; Coyle, P; Creusot, A; Curtil, C; De Bonis, G; Decowski, M P; Dekeyser, I; Deschamps, A; Distefano, C; Donzaud, C; Dornic, D; Dorosti, Q; Drouhin, D; Eberl, T; Emanuele, U; Enzenhoefer, A; Ernenwein, J -P; Escoffier, S; Fehn, K; Fermani, P; Ferri, M; Ferry, S; Flaminio, V; Folger, F; Fritsch, U; Fuda, J -L; Galata, S; Gay, P; Geyer, K; Giacomelli, G; Giordano, V; Gleixner, A; Gomez-Gonzalez, J P; Graf, K; Guillard, G; Hallewell, G; Hamal, M; van Haren, H; Heijboer, A J; Hello, Y; Hernandez-Rey, J J; Herold, B; Hoessl, J; Hsu, C C; de Jong, M; Kadler, M; Kalekin, O; Kappes, A; Katz, U; Kavatsyuk, O; Kooijman, P; Kopper, C; Kouchner, A; Kreykenbohm, I; Kulikovskiy, V; Lahmann, R; Lambard, G; Larosa, G; Lattuada, D; Lefevre, D; Lim, G; Presti, D Lo; Loehner, H; Loucatos, S; Louis, F; Mangano, S; Marcelin, M; Margiotta, A; Martinez-Mora, J A; Meli, A; Montaruli, T; Morganti, M; Moscoso, L; Motz, H; Neff, M; Nezri, E; Palioselitis, D; Pavalas, G E; Payet, K; Petrovic, J; Piattelli, P; Popa, V; Pradier, T; Presani, E; Racca, C; Reed, C; Riccobene, G; Richardt, C; Richter, R; Riviere, C; Robert, A; Roensch, K; Rostovtsev, A; Ruiz-Rivas, J; Rujoiu, M; Russo, G V; Samtleben, D F E; Sanchez-Losa, A; Sapienza, P; Schmid, J; Schnabel, J; Schoeck, F; Schuller, J -P; Schuessler, F; Seitz, T; Shanidze, R; Simeone, F; Spies, A; Spurio, M; Steijger, J J M; Stolarczyk, Th; Taiuti, M; Tamburini, C; Trovato, A; Vallage, B; Vallee, C; Van Elewyck, V; Vecchi, M; Vernin, P; Visser, E; Wagner, S; Wijnker, G; Wilms, J; de Wolf, E; Yepes, H; Zaborov, D; Zornoza, J D; Zuniga, J

    2012-01-01

    The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon neutrinos of such energies crossing the Earth. The parameters determining the oscillation of atmospheric neutrinos are extracted by fitting the event rate as a function of the ratio of the estimated neutrino energy and reconstructed flight path through the Earth. Measurement contours of the oscillation parameters in a two-flavour approximation are derived. Assuming maximum mixing, a mass difference of $\\Delta m_{32}^2=(3.1\\pm 0.9)\\cdot 10^{-3}$ eV$^2$ is obtained, in good agreement with the world average value.

  12. Measurement of atmospheric neutrino oscillations with the ANTARES neutrino telescope

    International Nuclear Information System (INIS)

    The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon neutrinos of such energies crossing the Earth. The parameters determining the oscillation of atmospheric neutrinos are extracted by fitting the event rate as a function of the ratio of the estimated neutrino energy and reconstructed flight path through the Earth. Measurement contours of the oscillation parameters in a two-flavour approximation are derived. Assuming maximal mixing, a mass difference of Δm322=(3.1±0.9)⋅10-3 eV2 is obtained, in good agreement with the world average value.

  13. Measurement of atmospheric neutrino oscillations with the ANTARES neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    Adrian-Martinez, S. [Institut d' Investigacio per a la Gestio Integrada de les Zones Costaneres (IGIC), Universitat Politecnica de Valencia, C/ Paranimf 1, 46730 Gandia (Spain); Al Samarai, I. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Albert, A. [GRPHE - Institut universitaire de technologie de Colmar, 34 rue du Grillenbreit, BP 50568, 68008 Colmar (France); Andre, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Rambla Exposicio, 08800 Vilanova i la Geltru, Barcelona (Spain); Anghinolfi, M. [INFN - Sezione di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Anton, G. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); Anvar, S. [Direction des Sciences de la Matiere, Institut de recherche sur les lois fondamentales de l' Univers, Service d' Electronique des Detecteurs et d' Informatique, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France); Ardid, M. [Institut d' Investigacio per a la Gestio Integrada de les Zones Costaneres (IGIC), Universitat Politecnica de Valencia, C/ Paranimf 1, 46730 Gandia (Spain); Astraatmadja, T. [Nikhef, Science Park, Amsterdam (Netherlands); Aubert, J.-J. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); and others

    2012-08-14

    The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon neutrinos of such energies crossing the Earth. The parameters determining the oscillation of atmospheric neutrinos are extracted by fitting the event rate as a function of the ratio of the estimated neutrino energy and reconstructed flight path through the Earth. Measurement contours of the oscillation parameters in a two-flavour approximation are derived. Assuming maximal mixing, a mass difference of {Delta}m{sub 32}{sup 2}=(3.1{+-}0.9) Dot-Operator 10{sup -3} eV{sup 2} is obtained, in good agreement with the world average value.

  14. Radiation power measurement on the ADITYA tokamak

    Science.gov (United States)

    Tahiliani, Kumudni; Jha, Ratneshwar; Gopalkrishana, M. V.; Doshi, Kalpesh; Rathod, Vipal; Hansalia, Chandresh; ADITYA Team

    2009-08-01

    The radiation power loss and its variation with plasma density and current are studied in the ADITYA tokamak. The radiation power loss varies from 20% to 40% of the input power for different discharges. The radiation fraction decreases with increasing plasma current but it increases with increasing line-averaged central density. The radiated power behavior has also been studied in discharges with short pulses of molecular beam injection (MBI) and gas puff (GP). The increase in radiation loss is limited to the edge chords in the case of GP, but it extends to the core region for MBI fueling. The MBI seems to indicate reduction in the edge recycling. It is observed that during the density limit disruption, the radiated power loss is more in the current quench phase as compared with the thermal quench phase and comes mainly from the plasma edge.

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

    Science.gov (United States)

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

    2015-05-01

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

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

    Directory of Open Access Journals (Sweden)

    N. Hanrieder

    2015-05-01

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

  17. Electromagnetically driven radiative shocks and their measurements

    International Nuclear Information System (INIS)

    Experimental results on a generation of strong shocks in a compact pulse power device are reported. The characteristics of strong shocks are different from hydrodynamical shocks' because they depend on not only collisions but radiation processes. Radiative shocks are relevant to high energy density phenomena such as the explosions of supernovae. When initial pressure is lower than about 50 mtorr, an interesting structure is confirmed at the shock front, which might indicate a phenomenon proceeded by the radiative process. (author)

  18. Schlieren measurements of the hydrodynamics of excimer laser ablation of polymers in atmospheric pressure gas

    Science.gov (United States)

    Ventzek, Peter L. G.; Gilgenbach, Ronald M.; Sell, Jeffrey A.; Heffelfinger, David M.

    1990-08-01

    Pulsed schlieren photography and fast helium-neon laser deflection are used to study the hydrodynamics of laser ablation of polyethyleneterephthalate and polymethylmethacrylate by pulsed KrF (248 nm) radiation in atmospheric air, Ar and N2. Schlieren measurements show the evolution of shock waves, sound waves, and reduced-density, hot gas plumes. A transition from sound to shock at the ablation threshold for both polymers is observed. The shock velocity of PET tends to approach agreement with blast wave theory at fluences higher than 1 J/cm2. Plumes in air are consistently larger than those produced in Ar and N2 (at fluences below 5 J/cm2) suggesting that combustion may occur. Laser deflection measurements for PET at 150 mJ/cm2 indicate a plume density of 0.6 kg/m3 (50% atmospheric density).

  19. Vacuum ultraviolet line radiation measurements of a shock-heated nitrogen plasma

    Science.gov (United States)

    Mcclenahan, J. O.

    1972-01-01

    Line radiation, in the wavelength region from 1040 to 2500 A from nitrogen plasmas, was measured at conditions typical of those produced in the shock layer in front of vehicles entering the earth's atmosphere at superorbital velocities. The radiation was also predicted with a typical radiation transport computer program to determine whether such calculations adequately model plasmas for the conditions tested. The results of the comparison show that the radiant intensities of the lines between 1040 and 1700 A are actually lower than are predicted by such computer models.

  20. Modulation in Ocean Primary Production due to Variability of Photosynthetically Available Radiation under Different Atmospheric Conditions

    Directory of Open Access Journals (Sweden)

    Madhumita Tripathy

    2014-01-01

    Full Text Available The rate of photosynthesis primarily depends on nutrients and photosynthetically available radiation (PAR at sea surface. Several ship cruises were carried out to measure optical, biological, and atmospheric parameters in the Arabian Sea and their variability were studied. An analytical nonspectral photosynthesis-irradiance model was used to estimate euphotic primary production (EuPP to study its variability during cruise periods. PAR was estimated using COART model using in situ measured aerosol optical depth (AOD to compare with in situ measured PAR. In order to understand the variability of PAR under different types of aerosol and different aerosol loading, a simulation study was carried out using COART model. EuPP was estimated for various PAR values under different aerosol loading and cloud coverage conditions. Sensitivity analysis showed that for maritime, maritime polluted, and desert aerosols, the ratio PAR/PAR0AOD has attenuated to about 11–25%, whereas it has attenuated to 44% for urban aerosol type. PAR/PARclear  sky was reduced by ~57% for high aerosol loading and for overcast sky. The decrease in EuPP under various aerosol loading and cloud coverage was observed to depend on the photoadaptation parameter. EuPP/EuPPclear  sky was reduced by 38% for maximum maritime aerosol loading and for overcast sky.

  1. Molecular radiation - Its application in physical measurements and analyses

    Science.gov (United States)

    1969-01-01

    Specialists Conference held at Marshall Space Flight Center reviewed work in molecular radiation to evaluate research possibilities in this field. Topics included spectral-line studies in the labortory, application to practical heat transfer calculations of radiative transfer models, and use of measured radiation properties of gases.

  2. New standards for ionizing radiation measurements

    International Nuclear Information System (INIS)

    The Ionizing Radiation Division has developed new national standards for mammographic X rays and for brachytherapy sources, such as iodine-125. The Attix chamber, a variable volume free-air ionization chamber, has been established as the primary national standard for mammographic X rays. The Attix chamber resides in the newly developed NIST Mammography Calibration Range and will be used to perform routine calibrations. The wide-angle free-air ionization chamber utilizes a large volume and a novel electric field configuration in order to circumvent the limitations of conventional free-air chambers. Seventeen beam qualities for X rays from molybdenum (Mo) and rhodium (Rh) anodes have been parameterized for the calibration of mammographic ionization chambers. The beam qualities available include anode/filter combinations of Mo/Mo, Mo/Rh and Rh/Rh. The mammography range was developed in collaborations with the U.S. Food and Drug Administration's (FDA) Center for Devices and Radiological Health, the implementors of the Mammography Quality Standards Act (MQSA) of 1992. The wide-angle free-air ionization chamber has been used to measure the output of two types of iodine-125 seeds, those with resin balls and those with silver wire. Both free-air chambers have been intercompared with the Ritz parallel-plate free-air ionization chamber

  3. Highly resolved measurements of atmospheric turbulence with the new 2d-Atmospheric Laser Cantilever Anemometer

    Science.gov (United States)

    Jeromin, A.; Schaffarczyk, A. P.; Puczylowski, J.; Peinke, J.; Hölling, M.

    2014-12-01

    For the investigation of atmospheric turbulent flows on small scales a new anemometer was developed, the so-called 2d-Atmospheric Laser Cantilever Anemometer (2d-ALCA). It performs highly resolved measurements with a spatial resolution in millimeter range and temporal resolution in kHz range, thus detecting very small turbulent structures. The anemometer is a redesign of the successfully operating 2d-LCA for laboratory application. The new device was designed to withstand hostile operating environments (rain and saline, humid air). In February 2012, the 2d-ALCA was used for the first time in a test field. The device was mounted in about 53 m above ground level on a lattice tower near the German North Sea coast. Wind speed was measured by the 2d-ALCA at 10 kHz sampling rate and by cup anemometers at 1 Hz. The instantaneous wind speed ranged from 8 m/s to 19 m/s at an average turbulence level of about 7 %. Wind field characteristics were analyzed based on cup anemometer as well as 2d-ALCA. The combination of both devices allowed the study of atmospheric turbulence over several magnitudes in turbulent scales.

  4. Optimizing a remote sensing instrument to measure atmospheric surface pressure

    Science.gov (United States)

    Peckham, G. E.; Gatley, C.; Flower, D. A.

    1983-01-01

    Atmospheric surface pressure can be remotely sensed from a satellite by an active instrument which measures return echoes from the ocean at frequencies near the 60 GHz oxygen absorption band. The instrument is optimized by selecting its frequencies of operation, transmitter powers and antenna size through a new procedure baesd on numerical simulation which maximizes the retrieval accuracy. The predicted standard deviation error in the retrieved surface pressure is 1 mb. In addition the measurements can be used to retrieve water vapor, cloud liquid water and sea state, which is related to wind speed.

  5. A spectroscopic transfer standard for accurate atmospheric CO measurements

    Science.gov (United States)

    Nwaboh, Javis A.; Li, Gang; Serdyukov, Anton; Werhahn, Olav; Ebert, Volker

    2016-04-01

    Atmospheric carbon monoxide (CO) is a precursor of essential climate variables and has an indirect effect for enhancing global warming. Accurate and reliable measurements of atmospheric CO concentration are becoming indispensable. WMO-GAW reports states a compatibility goal of ±2 ppb for atmospheric CO concentration measurements. Therefore, the EMRP-HIGHGAS (European metrology research program - high-impact greenhouse gases) project aims at developing spectroscopic transfer standards for CO concentration measurements to meet this goal. A spectroscopic transfer standard would provide results that are directly traceable to the SI, can be very useful for calibration of devices operating in the field, and could complement classical gas standards in the field where calibration gas mixtures in bottles often are not accurate, available or stable enough [1][2]. Here, we present our new direct tunable diode laser absorption spectroscopy (dTDLAS) sensor capable of performing absolute ("calibration free") CO concentration measurements, and being operated as a spectroscopic transfer standard. To achieve the compatibility goal stated by WMO for CO concentration measurements and ensure the traceability of the final concentration results, traceable spectral line data especially line intensities with appropriate uncertainties are needed. Therefore, we utilize our new high-resolution Fourier-transform infrared (FTIR) spectroscopy CO line data for the 2-0 band, with significantly reduced uncertainties, for the dTDLAS data evaluation. Further, we demonstrate the capability of our sensor for atmospheric CO measurements, discuss uncertainty calculation following the guide to the expression of uncertainty in measurement (GUM) principles and show that CO concentrations derived using the sensor, based on the TILSAM (traceable infrared laser spectroscopic amount fraction measurement) method, are in excellent agreement with gravimetric values. Acknowledgement Parts of this work have been

  6. A review on recent upper atmosphere atomic oxygen measurements

    Science.gov (United States)

    Kaufmann, Martin; Ern, Manfred; Riese, Martin; Zhu, Yajun

    2016-07-01

    Atomic oxygen is a key player in the upper mesosphere lower and thermosphere chemistry, energy balance, and dynamics. In recent years, a few new global datasets of this species have been presented. They are based on airglow measurements from low earth satellites. Surprisingly, the atomic oxygen abundance differs by 30-50% for similar atmospheric conditions. This paper gives an overview on the various atomic oxygen datasets available so far and presents most recent results obtained from measurements of the SCIAMACHY instrument on Envisat. Differences between the datasets are discussed.

  7. Review of measures to control radiation

    International Nuclear Information System (INIS)

    Methods used in Canada and the U.S.A. to overcome problems in the control of radiation, to prescribe standards and to ensure that compliance with the standards is achieved are reviewed. The relevant Acts and Regulations are outlined. Options which could be applied in Australia for effecting better control of radiation are suggested

  8. Solar radiation measurements from coordinated radiosonde flights during the 20th March 2015 solar eclipse

    Science.gov (United States)

    Harrison, R. Giles; Marlton, Graeme; Williams, Paul; Nicoll, Keri

    2016-04-01

    Solar radiation sensors can be carried on standard weather balloon packages and provide additional information about the atmosphere's vertical structure beyond the traditional thermodynamic measurements [1]. An interesting set of circumstances for such sensors occurs during a solar eclipse, which provides a rapidly changing solar radiation environment within the duration of a typical free balloon flight. Coordinating several launches of solar radiation measuring radiosondes brings a good likelihood of at least one being above any cloud during the maximum eclipse, allowing solar eclipse radiation measurements for comparison with theory. For the 20th March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44N, 0.94W), Lerwick (60.15N, 1.13W) and Reykjavik (64.13N, 21.90W), straddling the path of the eclipse. All three balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. These approaches, which are essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes. [1] K.A. Nicoll and R.G. Harrison, Balloon-borne disposable radiometer Rev Sci Instrum 83, 025111 (2012) doi: 10.1063/1.3685252

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

    Science.gov (United States)

    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.

  10. Clear-sky atmospheric radiative transfer : a model intercomparison for shortwave irradiances

    NARCIS (Netherlands)

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

    2008-01-01

    This study consists of an intercomparison of clear-sky shortwave irradiances calculated by the Doubling Adding model of KNMI (DAK) and the Simple Model of the Atmospheric Radiative Transfer of Sunshine (SMARTS). The DAK and SMARTS models are run with identical input (state profiles, water vapour, oz

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

    Science.gov (United States)

    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.

  12. Analytical Models of Exoplanetary Atmospheres. II. Radiative Transfer via the Two-Stream Approximation

    CERN Document Server

    Heng, Kevin; Lee, Jaemin

    2014-01-01

    We present a comprehensive analytical study of radiative transfer using the method of moments and include the effects of non-isotropic scattering in the coherent limit. Within this unified formalism, we derive the governing equations and solutions describing two-stream radiative transfer (which approximates the passage of radiation as a pair of outgoing and incoming fluxes), flux-limited diffusion (which describes radiative transfer in the deep interior) and solutions for the temperature-pressure profiles. Generally, the problem is mathematically under-determined unless a set of closures (Eddington coefficients) is specified. We demonstrate that the hemispheric (or hemi-isotropic) closure naturally derives from the radiative transfer equation if energy conservation is obeyed, while the Eddington closure produces spurious enhancements of both reflected light and thermal emission. We further demonstrate that traditional non-isothermal treatments of each atmospheric layer lead to unphysical contributions to the ...

  13. Non-linear Evolution of Rayleigh-Taylor Instability in a Radiation Supported Atmosphere

    CERN Document Server

    Jiang, Yan-Fei; Stone, James

    2012-01-01

    The non-linear 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 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 non-linear regime, dense fingers sink faster than rarefied bubbles can rise, leading to asymmetric structures about the interface. By comparing the calculations that use a variable Eddington tensor (VET) versus the Eddington approximation, we demonstrate that anisotropy in the radiation field can affect the non-linear development of RTI...

  14. Atmospheric velocity spectral width measurements using the statistical distribution of pulsed CO2 lidar return signal intensities

    Science.gov (United States)

    Ancellet, Gerard M.; Menzies, Robert T.; Grant, William B.

    1989-01-01

    A pulsed CO2 lidar with coherent detection has been used to measure the correlation time of backscatter from an ensemble of atmospheric aerosol particles which are illuminated by the pulsed radiation. The correlation time of the backscatter of the return signal, which is directly related to the velocity spectral width, can be used to study the velocity structure constant of atmospheric turbulence and wind shear. Various techniques for correlation time measurement are discussed, and several measurement results are presented for the technique using the information contained in the statistical distribution of a set of lidar return signal intensities.

  15. Integrated method for the measurement of trace nitrogenous atmospheric bases

    Science.gov (United States)

    Key, D.; Stihle, J.; Petit, J.-E.; Bonnet, C.; Depernon, L.; Liu, O.; Kennedy, S.; Latimer, R.; Burgoyne, M.; Wanger, D.; Webster, A.; Casunuran, S.; Hidalgo, S.; Thomas, M.; Moss, J. A.; Baum, M. M.

    2011-12-01

    Nitrogenous atmospheric bases are thought to play a key role in the global nitrogen cycle, but their sources, transport, and sinks remain poorly understood. Of the many methods available to measure such compounds in ambient air, few meet the current need of being applicable to the complete range of potential analytes and fewer still are convenient to implement using instrumentation that is standard to most laboratories. In this work, an integrated approach to measuring trace, atmospheric, gaseous nitrogenous bases has been developed and validated. The method uses a simple acid scrubbing step to capture and concentrate the bases as their phosphite salts, which then are derivatized and analyzed using GC/MS and/or LC/MS. The advantages of both techniques in the context of the present measurements are discussed. The approach is sensitive, selective, reproducible, as well as convenient to implement and has been validated for different sampling strategies. The limits of detection for the families of tested compounds are suitable for ambient measurement applications (e.g., methylamine, 1 pptv; ethylamine, 2 pptv; morpholine, 1 pptv; aniline, 1 pptv; hydrazine, 0.1 pptv; methylhydrazine, 2 pptv), as supported by field measurements in an urban park and in the exhaust of on-road vehicles.

  16. Integrated method for the measurement of trace atmospheric bases

    Science.gov (United States)

    Key, D.; Stihle, J.; Petit, J.-E.; Bonnet, C.; Depernon, L.; Liu, O.; Kennedy, S.; Latimer, R.; Burgoyne, M.; Wanger, D.; Webster, A.; Casunuran, S.; Hidalgo, S.; Thomas, M.; Moss, J. A.; Baum, M. M.

    2011-09-01

    Nitrogenous atmospheric bases are thought to play a key role in the global nitrogen cycle, but their sources, transport, and sinks remain poorly understood. Of the many methods available to measure such compounds in ambient air, few meet the current need of being applicable to the complete range of potential analytes and fewer still are convenient to implement using instrumentation that is standard to most laboratories. In this work, an integrated approach to measuring trace atmospheric nitrogenous bases has been developed and validated. The method uses a simple acid scrubbing step to capture and concentrate the bases as their phosphite salts, which then are derivatized and analyzed using GC/MS and/or LC/MS. The advantages of both techniques in the context of the present measurements are discussed. The approach is sensitive, selective, reproducible, as well as convenient to implement and has been validated for different sampling strategies. The limits of detection for the families of tested compounds are suitable for ambient measurement applications, as supported by field measurements in an urban park and in the exhaust of on-road vehicles.

  17. Integrated method for the measurement of trace atmospheric bases

    Directory of Open Access Journals (Sweden)

    D. Key

    2011-09-01

    Full Text Available Nitrogenous atmospheric bases are thought to play a key role in the global nitrogen cycle, but their sources, transport, and sinks remain poorly understood. Of the many methods available to measure such compounds in ambient air, few meet the current need of being applicable to the complete range of potential analytes and fewer still are convenient to implement using instrumentation that is standard to most laboratories. In this work, an integrated approach to measuring trace atmospheric nitrogenous bases has been developed and validated. The method uses a simple acid scrubbing step to capture and concentrate the bases as their phosphite salts, which then are derivatized and analyzed using GC/MS and/or LC/MS. The advantages of both techniques in the context of the present measurements are discussed. The approach is sensitive, selective, reproducible, as well as convenient to implement and has been validated for different sampling strategies. The limits of detection for the families of tested compounds are suitable for ambient measurement applications, as supported by field measurements in an urban park and in the exhaust of on-road vehicles.

  18. Failure and Redemption of Multifilter Rotating Shadowband Radiometer (MFRSR/Normal Incidence Multifilter Radiometer (NIMFR Cloud Screening: Contrasting Algorithm Performance at Atmospheric Radiation Measurement (ARM North Slope of Alaska (NSA and Southern Great Plains (SGP Sites

    Directory of Open Access Journals (Sweden)

    James Barnard

    2013-09-01

    Full Text Available Well-known cloud-screening algorithms, which are designed to remove cloud-contaminated aerosol optical depths (AOD from Multifilter Rotating Shadowband Radiometer (MFRSR and Normal Incidence Multifilter Radiometer (NIMFR measurements, have exhibited excellent performance at many middle-to-low latitude sites around world. However, they may occasionally fail under challenging observational conditions, such as when the sun is low (near the horizon and when optically thin clouds with small spatial inhomogeneity occur. Such conditions have been observed quite frequently at the high-latitude Atmospheric Radiation Measurement (ARM North Slope of Alaska (NSA sites. A slightly modified cloud-screening version of the standard algorithm is proposed here with a focus on the ARM-supported MFRSR and NIMFR data. The modified version uses approximately the same techniques as the standard algorithm, but it additionally examines the magnitude of the slant-path line of sight transmittance and eliminates points when the observed magnitude is below a specified threshold. Substantial improvement of the multi-year (1999–2012 aerosol product (AOD and its Angstrom exponent is shown for the NSA sites when the modified version is applied. Moreover, this version reproduces the AOD product at the ARM Southern Great Plains (SGP site, which was originally generated by the standard cloud-screening algorithms. The proposed minor modification is easy to implement and its application to existing and future cloud-screening algorithms can be particularly beneficial for challenging observational conditions.

  19. Atmospheric flow measurements using the PIV and HWA techniques

    Directory of Open Access Journals (Sweden)

    Luciana Bassi Marinho Pires

    2010-08-01

    Full Text Available Alcântara Space Center (ASC is the Brazilian gate to the space where rockets of different sizes are launched. At ASC there is a relative topographical variation, coastal cliff, which modifies the atmospheric boundary layer characteristics and can cause interference for operations of rockets. In the present work, a simplified model (mock-up was studied in a wind tunnel. A scale factor of 1:1000 was used and the atmospheric flow was measured using the hot wire anemometer (HWA and particle image velocimetry (PIV techniques. Using of HWA it was possible to calculate values of average wind speed and fluctuations in a set of points of the section of tests that representing the region of the ASC. Through these measures, other meteorological parameters that represent the atmospheric flow, such as the friction velocity (u*, the roughness length (z0 from the logarithmic profile and the alpha exponent (ɑ of the power law were calculated. With the use of the PIV´s technique, the streamlines and the vorticity fields were obtained and it was noticed that the vorticity generated downwind of the coastal cliff has a strong turbulence (vorticities around 2000 sˉ¹. A rectangular building (simulating the mobile integration tower was inserted at the mock-up and the downwind turbulence was similar to the one generated by the coastal cliff.

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

    CERN Document Server

    Aplin, Karen

    2015-01-01

    Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing traditionally distinct scientific boundaries. Following the paper of Erlykin et al. (Astropart. Phys. 57--58 (2014) 26--29) we develop the interpretation of observed changes in long-wave (LW) radiation (Aplin and Lockwood, Env. Res. Letts. 8, 015026 (2013)), by taking account of 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 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 were not caused by individual cosmic ray primaries -- not b...

  1. 225 GHz Atmospheric Opacity Measurements from Two Arctic Sites

    CERN Document Server

    Matsushita, S; Martin-Cocher, P; Asada, K; Chen, C -P; Inoue, M; Paine, S; Turner, D; Steinbring, E

    2012-01-01

    We report the latest results of 225 GHz atmospheric opacity measurements from two arctic sites; one on high coastal terrain near the Eureka weather station, on Ellesmere Island, Canada, and the other at the Summit Station near the peak of the Greenland icecap. This is a campaign to search for a site to deploy a new telescope for submillimeter Very Long Baseline Interferometry and THz astronomy in the northern hemisphere. Since 2011, we have obtained 3 months of winter data near Eureka, and about one year of data at the Summit Station. The results indicate that these sites offer a highly transparent atmosphere for observations in submillimeter wavelengths. The Summit Station is particularly excellent, and its zenith opacity at 225 GHz is statistically similar to the Atacama Large Milllimeter/submillimeter Array in Chile. In winter, the opacity at the Summit Station is even comparable to that observed at the South Pole.

  2. Radiation detection and measurement student solutions manual

    CERN Document Server

    Wehe, David K

    2012-01-01

    This is the resource that engineers turn to in the study of radiation detection. The fourth edition takes into account the technical developments that continue to enhance the instruments and techniques available for the detection and spectroscopy of ionizing radiation. New coverage is presented on ROC curves, micropattern gas detectors, new sensors for scintillation light, and the excess noise factor. Revised discussions are also included on TLDs and cryogenic spectrometers, radiation backgrounds, and the VME standard. Engineers will gain a strong understanding of the field with this updated book.

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

    Science.gov (United States)

    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

  4. The role of VUV radiation in the inactivation of bacteria with an atmospheric pressure plasma jet

    CERN Document Server

    Schneider, Simon; Ellerweg, Dirk; Denis, Benjamin; Narberhaus, Franz; Bandow, Julia E; Benedikt, Jan

    2011-01-01

    A modified version of a micro scale atmospheric pressure plasma jet (\\mu-APPJ) source, so-called X-Jet, is used to study the role of plasma generated VUV photons in the inactivation of E. coli bacteria. The plasma is operated in He gas or a He/O2 mixture and the X-Jet modification of the jet geometry allows effective separation of heavy reactive particles (such as O atoms or ozone molecules) from the plasma-generated photons. The measurements of the evolution of zone of inhibitions formed in monolayers of vegetative E. coli bacteria, of VUV emission intensity and of positive ion spectra show that photochemistry in the gas phase followed by photochemistry products impacting on bacteria can result in bacterial inactivation. Interestingly, this process is more effective than direct inactivation by VUV radiation damage. Mainly protonated water cluster ions are detected by mass spectrometry indicating that water impurity has to be carefully considered. The measurements indicate that the combination of the presence...

  5. Electron Density and Temperature Measurements, and Abundance Anomalies in the Solar Atmosphere

    Indian Academy of Sciences (India)

    Anita Mohan; Bhola N. Dwivedi; Enrico Landi

    2000-09-01

    Using spectra obtained from the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrograph on the spacecraft SOHO (Solar and Heliospheric Observatory), we investigate the height dependence of electron density, temperature and abundance anomalies in the solar atmosphere. In particular, we present the behaviour of the solar FIP effect (the abundance enhancement of elements with first ionization potential < 10 eV in the corona with respect to photospheric values) with height above an active region observed at the solar limb, with emphasis on the so-called transition region lines.

  6. About Solar Radiation Intensity Measurements and Data Processing

    Directory of Open Access Journals (Sweden)

    MICH-VANCEA Claudiu

    2012-10-01

    Full Text Available Measuring the intensity of solar radiation is one of the directions of investigation necessary for the implementation of photovoltaic systems in a particular geographical area. This can be done by using specific measuring equipment (pyranometer sensors based onthermal or photovoltaic principle. In this paper it is presented a method for measuring solar radiation (which has two main components - direct radiation and diffuse radiation with sensors based on photovoltaic principle. Such data are processed for positioning solarpanels, in order their efficiency to be maximized.

  7. Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms

    Directory of Open Access Journals (Sweden)

    S.-L. Sihto

    2006-05-01

    Full Text Available We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took place in spring 2003 in Hyytiälä (Finland. During the campaign numerous new aerosol particle formation events occurred of which 15 were accompanied by gaseous sulphuric acid measurements. Our detailed analysis of these 15 events is focussed on nucleation and early growth (to a diameter of 3 nm of fresh particles. It revealed that new particle formation seems to be a function of the gaseous sulphuric acid concentration to the power from one to two. The former would be consistent with the recently developed activation theory while the latter would be consistent with the kinetic nucleation theory. We find that some events are dominated by the activation mechanism and some are dominated by the kinetic mechanism. Inferred coefficients for the two nucleation mechanisms are correlated with the product of gaseous sulphuric acid and ammonia concentrations. This indicates that besides gaseous sulphuric acid also ammonia has a role in nucleation. Early growth of fresh particles to a diameter of 3 nm has a mean rate of 1.2 nm/h and is clearly correlated with the gaseous sulphuric acid concentration.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Continuous measurements of greenhouse gases and atmospheric oxygen at the Namib Desert Atmospheric Observatory

    Directory of Open Access Journals (Sweden)

    E. J. Morgan

    2015-02-01

    Full Text Available A new coastal background site has been established for observations of greenhouse gases (GHGs in the central Namib Desert at Gobabeb, Namibia. The location of the site was chosen to provide observations for a data-poor region in the global sampling network for GHGs. Semi-automated, continuous measurements of carbon dioxide, methane, nitrous oxide, carbon monoxide, atmospheric oxygen, and basic meteorology are made at a height of 21 m a.g.l., 50 km from the coast at the northern border of the Namib Sand Sea. Atmospheric oxygen is measured with a differential fuel cell analyzer (DFCA. Carbon dioxide and methane are measured with an early-model cavity ring-down spectrometer (CRDS; nitrous oxide and carbon monoxide are measured with an off-axis integrated cavity output spectrometer (OA-ICOS. Instrument-specific water corrections are employed for both the CRDS and OA-ICOS instruments in lieu of drying. The performance and measurement uncertainties are discussed in detail. As the station is located in a remote desert environment, there are some particular challenges, namely fine dust, high diurnal temperature variability, and minimal infrastructure. The gas handling system and calibration scheme were tailored to best fit the conditions of the site. The CRDS and DFCA provide data of acceptable quality when base requirements for operation are met, specifically adequate temperature control in the laboratory and regular supply of electricity. In the case of the OA-ICOS instrument, performance is significantly improved through the implementation of a drift correction through frequent measurements of a working tank.

  10. Continuous measurements of greenhouse gases and atmospheric oxygen at the Namib Desert Atmospheric Observatory

    Science.gov (United States)

    Morgan, E. J.; Lavrič, J. V.; Seifert, T.; Chicoine, T.; Day, A.; Gomez, J.; Logan, R.; Sack, J.; Shuuya, T.; Uushona, E. G.; Vincent, K.; Schultz, U.; Brunke, E.-G.; Labuschagne, C.; Thompson, R. L.; Schmidt, S.; Manning, A. C.; Heimann, M.

    2015-02-01

    A new coastal background site has been established for observations of greenhouse gases (GHGs) in the central Namib Desert at Gobabeb, Namibia. The location of the site was chosen to provide observations for a data-poor region in the global sampling network for GHGs. Semi-automated, continuous measurements of carbon dioxide, methane, nitrous oxide, carbon monoxide, atmospheric oxygen, and basic meteorology are made at a height of 21 m a.g.l., 50 km from the coast at the northern border of the Namib Sand Sea. Atmospheric oxygen is measured with a differential fuel cell analyzer (DFCA). Carbon dioxide and methane are measured with an early-model cavity ring-down spectrometer (CRDS); nitrous oxide and carbon monoxide are measured with an off-axis integrated cavity output spectrometer (OA-ICOS). Instrument-specific water corrections are employed for both the CRDS and OA-ICOS instruments in lieu of drying. The performance and measurement uncertainties are discussed in detail. As the station is located in a remote desert environment, there are some particular challenges, namely fine dust, high diurnal temperature variability, and minimal infrastructure. The gas handling system and calibration scheme were tailored to best fit the conditions of the site. The CRDS and DFCA provide data of acceptable quality when base requirements for operation are met, specifically adequate temperature control in the laboratory and regular supply of electricity. In the case of the OA-ICOS instrument, performance is significantly improved through the implementation of a drift correction through frequent measurements of a working tank.

  11. Using a simple apparatus to measure direct and diffuse photosynthetically active radiation at remote locations.

    Directory of Open Access Journals (Sweden)

    Michael J Cruse

    Full Text Available Plant canopy interception of photosynthetically active radiation (PAR drives carbon dioxide (CO2, water and energy cycling in the soil-plant-atmosphere system. Quantifying intercepted PAR requires accurate measurements of total incident PAR above canopies and direct beam and diffuse PAR components. While some regional data sets include these data, e.g. from Atmospheric Radiation Measurement (ARM Program sites, they are not often applicable to local research sites because of the variable nature (spatial and temporal of environmental variables that influence incoming PAR. Currently available instrumentation that measures diffuse and direct beam radiation separately can be cost prohibitive and require frequent adjustments. Alternatively, generalized empirical relationships that relate atmospheric variables and radiation components can be used but require assumptions that increase the potential for error. Our goal here was to construct and test a cheaper, highly portable instrument alternative that could be used at remote field sites to measure total, diffuse and direct beam PAR for extended time periods without supervision. The apparatus tested here uses a fabricated, solar powered rotating shadowband and other commercially available parts to collect continuous hourly PAR data. Measurements of total incident PAR had nearly a one-to-one relationship with total incident radiation measurements taken at the same research site by an unobstructed point quantum sensor. Additionally, measurements of diffuse PAR compared favorably with modeled estimates from previously published data, but displayed significant differences that were attributed to the important influence of rapidly changing local environmental conditions. The cost of the system is about 50% less than comparable commercially available systems that require periodic, but not continual adjustments. Overall, the data produced using this apparatus indicates that this instrumentation has the

  12. Atmospheric Measurements over Arctic Sea Ice from Winter to Summer: Preliminary Results from N-ICE 2015

    Science.gov (United States)

    Cohen, L.; Walden, V. P.; Hudson, S. R.

    2015-12-01

    With large changes the in Arctic sea ice regime observed in recent decades, the Arctic is becoming more dominated by thin, first-year ice as opposed to thick, multi-year ice. The recently-completed Norwegian young sea ICE cruise (N-ICE2015) made measurements north of Svalbard from a ship drifting within the Arctic sea ice pack from mid-winter into summer (January—June 2015). The purpose of the experiment was to provide better understanding of the drivers and effects within this new sea ice regime in the Arctic. This extensive measurement campaign made concurrent, in-situ measurements of all aspects of the Arctic sea ice system including atmosphere, ocean, sea ice, snowpack, and biology. The atmosphere plays a key role in the sea ice system, thus, observations were made of the meteorological conditions, radiative fluxes, boundary layer properties, turbulent fluxes, clouds, and atmospheric profiles. Interestingly, the atmospheric circulation in this region during this period was very different during January to March than in April to June. This led to very different meteorological and radiative balance regimes during these two periods, with much larger variability in winter. We will present preliminary data from the atmospheric observations made throughout the campaign, which offer clues to how large-scale atmospheric circulation affects energy balance and heat and moisture transport in the Arctic.

  13. Calibration of solar radiation measuring instruments. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bahm, R J; Nakos, J C

    1979-11-01

    A review of solar radiation measurement of instruments and some types of errors is given; and procedures for calibrating solar radiation measuring instruments are detailed. An appendix contains a description of various agencies who perform calibration of solar instruments and a description of the methods they used at the time this report was prepared. (WHK)

  14. Atmospheric Temperature Profile Measurements Using Mobile High Spectral Resolution Lidar

    Science.gov (United States)

    Razenkov, Ilya I.; Eloranta, Edwin W.

    2016-06-01

    The High Spectral Resolution Lidar (HSRL) designed at the University of Wisconsin-Madison discriminates between Mie and Rayleigh backscattering [1]. It exploits the Doppler effect caused by thermal motion of molecules, which broadens the spectrum of the transmitted laser light. That allows for absolute calibration of the lidar and measurements of the aerosol volume backscatter coefficient. Two iodine absorption filters with different absorption line widths (a regular iodine vapor filter and Argon buffered iodine filter) allow for atmospheric temperature profile measurements. The sensitivity of the measured signal-to-air temperature ratio is around 0.14%/K. The instrument uses a shared telescope transmitter-receiver design and operates in eyesafe mode (the product of laser average power and telescope aperture equals 0.1 Wm2 at 532 nm).

  15. Atmospheric Temperature Profile Measurements Using Mobile High Spectral Resolution Lidar

    Directory of Open Access Journals (Sweden)

    Razenkov Ilya I.

    2016-01-01

    Full Text Available The High Spectral Resolution Lidar (HSRL designed at the University of Wisconsin-Madison discriminates between Mie and Rayleigh backscattering [1]. It exploits the Doppler effect caused by thermal motion of molecules, which broadens the spectrum of the transmitted laser light. That allows for absolute calibration of the lidar and measurements of the aerosol volume backscatter coefficient. Two iodine absorption filters with different absorption line widths (a regular iodine vapor filter and Argon buffered iodine filter allow for atmospheric temperature profile measurements. The sensitivity of the measured signal-to-air temperature ratio is around 0.14%/K. The instrument uses a shared telescope transmitter-receiver design and operates in eyesafe mode (the product of laser average power and telescope aperture equals 0.1 Wm2 at 532 nm.

  16. Investigation of atmospheric diffusion by immission measurements of xenon-133 from Fessenheim nuclear power station

    International Nuclear Information System (INIS)

    The atmospheric xenon radioactivity was measured from mid 1983 to the end of 1984 in the surroundings of Fessenheim nuclear power station on the right bank of the Rhine. The level of activity (annual mean at Hartheim 1.6 pCi/m3 against a background of about 0.2 pCi/m3) makes it possible to carry out a diffusion study. Using a one-dimensional Gauss model, expected values of immission were calculated, taking into account the average strength of the source. Radiation balance, degree of cover or global radiation/degree of cover and wind speed, were used as parameters for atmospheric stability. The agreement between the calculated and measured immission based on weekly averages is satisfactory: about 2/3 of all calculated immissions deviate by less than a factor of 3.5 from the measured values. The accuracy of prediction of the model rises for longer averaging periods; for three months averaging, there is a factor of 1.5 deviation. The drop in concentration between the stations at different distances from the source is predicted too steeply by a factor of 1.5 by the model. (orig.)

  17. Investigation of atmospheric diffusion by immission measurements of xenon-133 from Fessenheim nuclear power station

    International Nuclear Information System (INIS)

    The atmospheric xenon radioactivity was measured from mid 1983 to the end of 1984 in the surroundings of Fessenheim nuclear power station on the right bank of the Rhine. The level of activity (annual mean at Hartheim 1.6 pCi/m3 against a background of about 0.2 pCi/m3) makes it possible to carry out a diffusion study. Using a one-dimensional Gauss model, expected values of immission were calculated, taking into account the average strength of the source. Radiation balance, degree of cover or global radiation/ degree of cover and wind speed, were used as parameters for atmospheric stability. The agreement between the calculated and measured immission based on weekly averages is satisfactory: about 2/3 of all calculated immissions deviate by less than a factor of 3.5 from the measured values. The accuracy of prediction of the model rises for longer averaging periods; for three months averaging, there is a factor of 1.5 deviation. The drop in concentration between the stations at different distances from the source is predicted too steeply by a factor of 1.5 by the model. (orig./HP)

  18. Comparing radial velocities of atmospheric lines with radiosonde measurements

    CERN Document Server

    Figueira, P; Chacon, A; Lovis, C; Santos, N C; Curto, G Lo; Sarazin, M; Pepe, F

    2011-01-01

    The precision of radial velocity (RV) measurements depends on the precision attained on the wavelength calibration. One of the available options is using atmospheric lines as a natural, freely available wavelength reference. Figueira et al. (2010) measured the RV of O2 lines using HARPS and showed that the scatter was only of ~10 m/s over a timescale of 6 yr. Using a simple but physically motivated empirical model, they demonstrated a precision of 2 m/s, roughly twice the average photon noise contribution. In this paper we take advantage of a unique opportunity to confirm the sensitivity of the telluric absorption lines RV to different atmospheric and observing conditions: by means of contemporaneous in-situ wind measurements by radiosondes. The RV model fitting yielded similar results to that of Figueira et al. (2010), with lower wind magnitude values and varied wind direction. The probes confirmed the average low wind magnitude and suggested that the average wind direction is a function of time as well. The...

  19. RF impedance measurements of DC atmospheric micro-discharges

    CERN Document Server

    Overzet, Lawrence J; Mandra, Monali; Goeckner, Matthew; Dufour, Thierry; Dussart, Remi; Lefaucheux, Philippe

    2016-01-01

    The available diagnostics for atmospheric micro-plasmas remain limited and relatively complex to implement; so we present a radio-frequency technique for diagnosing a key parameter here. The technique allows one to estimate the dependencies of the electron density by measuring the RF-impedance of the micro-plasma and analyzing it with an appropriate equivalent circuit. This technique is inexpensive, can be used in real time and gives reasonable results for argon and helium DC micro-plasmas in holes over a wide pressure range. The electron density increases linearly with current in the expected range consistent with normal glow discharge behavior.

  20. Agricultural measures to reduce radiation doses to man caused by severe nuclear accidents

    International Nuclear Information System (INIS)

    Agricultural land and products may become contaminated after a severe nuclear accident. If radiation doses to man caused by the ingestion of contaminated agricultural products from such areas will be unacceptably high, measures to reduce this radiation dose will have to be taken. Radiation doses to man can be estimated by using models which describe quantitatively the transfer of radionuclides through the biosphere. The following processes and pathways are described in this study: accidental releases into atmospheric environments and subsequent nearby deposition; contamination of crops by direct deposition and the subsequent short term pathway (e.g. grass-cow-milk-man); contamination of soil and the subsequent long term pathway (e.g. soil-crop-man, soil-grass-cattle-milk/meat-man). Depending on the degree of contamination and on the estimated radiation doses to man, various measures are advised. (Auth.)

  1. Analysis of a Kalman filter based method for on-line estimation of atmospheric dispersion parameters using radiation monitoring data

    International Nuclear Information System (INIS)

    A Kalman filter method is discussed for on-line estimation of radioactive release and atmospheric dispersion from a time series of off-site radiation monitoring data. The method is based on a state space approach, where a stochastic system equation describes the dynamics of the plume model parameters, and the observables are linked to the state variables through a static measurement equation. The method is analysed for three simple state space models using experimental data obtained at a nuclear research reactor. Compared to direct measurements of the atmospheric dispersion, the Kalman filter estimates are found to agree well with the measured parameters, provided that the radiation measurements are spread out in the cross-wind direction. For less optimal detector placement it proves difficult to distinguish variations in the source term and plume height; yet the Kalman filter yields consistent parameter estimates with large associated uncertainties. Improved source term assessment results, when independent estimates of the plume height can be used. Perspectives for using the method in the context of nuclear emergency management are discussed, and possible extensions to the present modelling scheme are outlined, to account for realistic accident scenarios. (authors)

  2. On the marine atmospheric boundary layer characteristics over Bay of Bengal and Arabian Sea during the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB)

    Indian Academy of Sciences (India)

    Denny P Alappattu; D Bala Subrahamanyam; P K Kunhikrishnan; K M Somayaji; G S Bhat; R Venkatesan; C B S Dutt; A Bagavath Singh; V K Soni; A S Tripathi

    2008-07-01

    Detailed measurements were carried out in the Marine Atmospheric Boundary Layer (MABL) during the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) which covered both Arabian Sea and Bay of Bengal during March to May 2006. In this paper, we present the meteorological observations made during this campaign. The latitudinal variation of the surface layer turbulent fluxes is also described in detail.

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

    Science.gov (United States)

    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.

  4. A New Laser Based Approach for Measuring Atmospheric Greenhouse Gases

    Directory of Open Access Journals (Sweden)

    Jeremy Dobler

    2013-11-01

    Full Text Available In 2012, we developed a proof-of-concept system for a new open-path laser absorption spectrometer concept for measuring atmospheric CO2. The measurement approach utilizes high-reliability all-fiber-based, continuous-wave laser technology, along with a unique all-digital lock-in amplifier method that, together, enables simultaneous transmission and reception of multiple fixed wavelengths of light. This new technique, which utilizes very little transmitted energy relative to conventional lidar systems, provides high signal-to-noise (SNR measurements, even in the presence of a large background signal. This proof-of-concept system, tested in both a laboratory environment and a limited number of field experiments over path lengths of 680 m and 1,600 m, demonstrated SNR values >1,000 for received signals of ~18 picoWatts averaged over 60 s. A SNR of 1,000 is equivalent to a measurement precision of ±0.001 or ~0.4 ppmv. The measurement method is expected to provide new capability for automated monitoring of greenhouse gas at fixed sites, such as carbon sequestration facilities, volcanoes, the short- and long-term assessment of urban plumes, and other similar applications. In addition, this concept enables active measurements of column amounts from a geosynchronous orbit for a network of ground-based receivers/stations that would complement other current and planned space-based measurement capabilities.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  7. Effect of ambient pressure and radiation reabsorption of atmosphere on the flame spreading over thermally thin combustibles in microgravity

    Institute of Scientific and Technical Information of China (English)

    杜文峰; 胡文瑞

    2003-01-01

    For the flame spread over thermally thin combustibles in an atmosphere, if the atmosphere cannot emit and absorb the thermal radiation (e.g. for atmosphere of O2-N2), the conductive heat transfer from the flame to the fuel surface dominates the flame spread at lower ambient atmosphere. As the ambient pressure increases, the flame spread rate increases, and the radiant heat transfer from the flame to the fuel surface gradually becomes the dominant driving force for the flame spread. In contrast, if the atmosphere is able to emit and absorb the thermal radiation (e.g. for atmosphere of O2-CO2), at lower pressure, the heat transfer from flame to the fuel surface is enhanced by the radiation reabsorption of the atmosphere at the leading edge of the flame, and both conduction and thermal radiation play important roles in the mechanism of flame spread. With the increase in ambient pressure, the oxygen diffuses more quickly from ambient atmosphere into the flame, the chemical reaction in the flame is enhanced, and the flame spread rate increases. When the ambient pressure is greater than a critical value, the thermal radiation from the flame to the solid surface is hampered by the radiation reabsorption of ambient atmosphere with the further increase in ambient pressure. As a result, with the increase in ambient pressure, the flame spread rate decreases and the heat conduction gradually dominates the flame spread over the fuel surface.

  8. Airborne spectral radiation measurements to derive solar radiative forcing of Saharan dust mixed with biomass burning smoke particles

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, S.; Bierwirth, E.; Wendisch, M. (Leipzig Inst. for Meteorology (LIM), Univ. of Leipzig, Leipzig (Germany)), e-mail: s.bauer@uni-leipzig.de; Esselborn, M.; Petzold, A.; Trautmann, T. (Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Oberpfaffenhofen (Germany)); Macke, A. (Leibniz Inst. for Tropospheric Research (IfT) (Germany))

    2011-09-15

    Airborne measurements of upward solar spectral irradiances were performed during the second Saharan Mineral dUst experiMent (SAMUM-2) campaign based on the Cape Verde Islands. Additionally, airborne high resolution lidar measurements of vertical profiles of particle extinction coefficients were collected in parallel to the radiation data. Aerosol layers of Saharan dust, partly mixed with biomass-burning smoke, were probed. With corresponding radiative transfer simulations the single scattering albedo and the asymmetry parameter of the aerosol particles were derived although with high uncertainty. The broad-band aerosol solar radiative forcing at the top of atmosphere was calculated and examined as a function of the aerosol types. However, due to uncertainties in both the measurements and the calculations the chemical composition cannot be identified. In addition, a mostly measurement-based method to derive the broad-band aerosol solar radiative forcing was used. This approach revealed clear differences of broad-band net irradiances as a function of the aerosol optical depth. The data were used to identify different aerosol types from different origins. Higher portions of biomass-burning smoke lead to larger broad-band net irradiances

  9. Evaluation and application of passive and active optical remote sensing methods for the measurement of atmospheric aerosol properties

    Energy Technology Data Exchange (ETDEWEB)

    Mielonen, T.

    2010-07-01

    Atmospheric aerosol particles affect the atmosphere's radiation balance by scattering and absorbing sunlight. Moreover, the particles act as condensation nuclei for clouds and affect their reflectivity. In addition, aerosols have negative health effects and they reduce visibility. Aerosols are emitted into the atmosphere from both natural and anthropogenic sources. Different types of aerosols have different effects on the radiation balance, thus global monitoring and typing of aerosols is of vital importance. In this thesis, several remote sensing methods used in the measurement of atmospheric aerosols are evaluated. Remote sensing of aerosols can be done with active and passive instruments. Passive instruments measure radiation emitted by the sun and the Earth while active instruments have their own radiation source, for example a black body radiator or laser. The instruments utilized in these studies were sun photometers (PFR, Cimel), lidars (POLLYXT, CALIOP), transmissiometer (OLAF) and a spectroradiometer (MODIS). Retrieval results from spaceborne instruments (MODIS, CALIOP) were evaluated with ground based measurements (PFR, Cimel). In addition, effects of indicative aerosol model assumptions on the calculated radiative transfer were studied. Finally, aerosol particle mass at the ground level was approximated from satellite measurements and vertical profiles of aerosols measured with a lidar were analyzed. For the evaluation part, these studies show that the calculation of aerosol induced attenuation of radiation based on aerosol size distribution measurements is not a trivial task. In addition to dry aerosol size distribution, the effect of ambient relative humidity on the size distribution and the optical properties of the aerosols need to be known in order to achieve correct results from the calculations. Furthermore, the results suggest that aerosol size parameters retrieved from passive spaceborne measurements depend heavily on surgace reflectance

  10. Inversion of Atmospheric Tracer Measurements, Localization of Sources

    Science.gov (United States)

    Issartel, J.-P.; Cabrit, B.; Hourdin, F.; Idelkadi, A.

    When abnormal concentrations of a pollutant are observed in the atmosphere, the question of its origin arises immediately. The radioactivity from Tchernobyl was de- tected in Sweden before the accident was announced. This situation emphasizes the psychological, political and medical stakes of a rapid identification of sources. In tech- nical terms, most industrial sources can be modeled as a fixed point at ground level with undetermined duration. The classical method of identification involves the cal- culation of a backtrajectory departing from the detector with an upstream integration of the wind field. We were first involved in such questions as we evaluated the ef- ficiency of the international monitoring network planned in the frame of the Com- prehensive Test Ban Treaty. We propose a new approach of backtracking based upon the use of retroplumes associated to available measurements. Firstly the retroplume is related to inverse transport processes, describing quantitatively how the air in a sam- ple originates from regions that are all the more extended and diffuse as we go back far in the past. Secondly it clarifies the sensibility of the measurement with respect to all potential sources. It is therefore calculated by adjoint equations including of course diffusive processes. Thirdly, the statistical interpretation, valid as far as sin- gle particles are concerned, should not be used to investigate the position and date of a macroscopic source. In that case, the retroplume rather induces a straightforward constraint between the intensity of the source and its position. When more than one measurements are available, including zero valued measurements, the source satisfies the same number of linear relations tightly related to the retroplumes. This system of linear relations can be handled through the simplex algorithm in order to make the above intensity-position correlation more restrictive. This method enables to manage in a quantitative manner the

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  13. McSCIA: application of the Equivalence Theorem in a Monte Carlo radiative transfer model for spherical shell atmospheres

    Directory of Open Access Journals (Sweden)

    F. Spada

    2006-02-01

    Full Text Available A new multiple-scattering Monte Carlo 3-D radiative transfer model named McSCIA (Monte Carlo for SCIAmachy is presented. The backward technique is used to efficiently simulate narrow field of view instruments. The McSCIA algorithm has been formulated as a function of the Earth's radius, and can thus perform simulations for both plane-parallel and spherical atmospheres. The latter geometry is essential for the interpretation of limb satellite measurements, as performed by SCIAMACHY on board of ESA's Envisat. The model can simulate UV-vis-NIR radiation.

    First the ray-tracing algorithm is presented in detail, and then successfully validated against literature references, both in plane-parallel and in spherical geometry. A simple 1-D model is used to explain two different ways of treating absorption. One method uses the single scattering albedo while the other uses the equivalence theorem. The equivalence theorem is based on a separation of absorption and scattering. It is shown that both methods give, in a statistical way, identical results for a wide variety of scenarios. Both absorption methods are included in McSCIA, and it is shown that also for a 3-D case both formulations give identical results. McSCIA limb profiles for atmospheres with and without absorption compare well with the one of the state of the art Monte Carlo radiative transfer model MCC++.

    A simplification of the photon statistics may lead to very fast calculations of absorption features in the atmosphere. However, these simplifications potentially introduce biases in the results. McSCIA does not use simplifications and is therefore a relatively slow implementation of the equivalence theorem. For the first time, however, the validity of the equivalence theorem is demonstrated in a spherical 3-D radiative transfer model.

  14. Fourier Transform Spectrometer measurements of Atmospheric Carbon Dioxide and Methane

    Science.gov (United States)

    Kivi, Rigel; Heikkinen, Pauli; Chen, Huilin; Hatakka, Juha; Laurila, Tuomas

    2016-04-01

    Ground based remote sensing measurements of column CO2 and CH4 using Fourier Transform Spectrometers (FTS) within the Total Carbon Column Observing Network (TCCON) are known for high precision and accuracy. These measurements are performed at various locations globally and they have been widely used in carbon cycle studies and validation of space born measurements. The relevant satellite missions include the Orbiting Carbon Observatory-2 (OCO-2) by the National Aeronautics and Space Administration (NASA); the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) by the European Space Agency (ESA); the Greenhouse gases Observing SATellite (GOSAT) by the Japan Aerospace Exploration Agency (JAXA) and the upcoming Sentinel-5 Precursor mission, which is an ESA mission and scheduled for launch in 2016. Results of the column CO2 and CH4 measurements at Sodankylä in northern Finland (at 67.4° N, 26.6° E) are reported in this study. The measurements have been performed on regular basis since the beginning of the program in early 2009. We also present evaluation of the data quality of the ground based measurements and comparisons with the available satellite based retrievals. In case of comparisons between the GOSAT and ground based retrievals of CO2 and CH4 no significant biases were found. Sodankylä is one of the northernmost stations in the TCCON network. However, the data coverage has been relatively good thanks to the progress towards automation of the FTS measurement system. At Sodankylä the retrievals have been also compared with the balloon borne AirCore measurements at the site. AirCore sampling system is directly related to the World Meteorological Organization in situ trace gas measurement scales. The balloon platform allows sampling in both stratosphere and troposphere, which is a benefit, compared to the aircraft in situ measurements.

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

    Science.gov (United States)

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

    2009-03-01

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

  16. Atmospheres and radiating surfaces of neutron stars with strong magnetic fields

    CERN Document Server

    Potekhin, A Y; Chabrier, G

    2016-01-01

    We review the current status of the theory of thermal emission from the surface layers of neutron stars with strong magnetic fields $B\\sim 10^{10}-10^{15}$ G, including formation of the spectrum in a partially ionized atmosphere and at a condensed surface. In particular, we describe recent progress in modeling partially ionized atmospheres of central compact objects in supernova remnants, which may have moderately strong fields $B\\sim 10^{10}-10^{11}$ G. Special attention is given to polarization of thermal radiation emitted by a neutron star surface. Finally, we briefly describe applications of the theory to observations of thermally emitting isolated neutron stars.

  17. Ground-based lidar for atmospheric boundary layer ozone measurements.

    Science.gov (United States)

    Kuang, Shi; Newchurch, Michael J; Burris, John; Liu, Xiong

    2013-05-20

    Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniques, and preliminary results that focus on the high-temporal profiling of ozone within the atmospheric boundary layer (ABL) achieved by the addition of an inexpensive and compact mini-receiver to the previous system. For the first time, to the best of our knowledge, the lowest, consistently achievable observation height has been extended down to 125 m AGL for a ground-based ozone lidar system. Both the analysis and preliminary measurements demonstrate that this lidar measures ozone with a precision generally better than ±10% at a temporal resolution of 10 min and a vertical resolution from 150 m at the bottom of the ABL to 550 m at the top. A measurement example from summertime shows that inhomogeneous ozone aloft was affected by both surface emissions and the evolution of ABL structures.

  18. Atmospheric Aerosol Attenuation Measurements at the Pierre Auger Observatory

    CERN Document Server

    Valore, Laura

    2014-01-01

    The Fluorescence Detector (FD) of the Pierre Auger Observatory provides a nearly calorimetric measurement of the primary particle energy, since the fluorescence light produced is proportional to the energy dissipated by an Extensive Air Shower (EAS) in the atmosphere. The atmosphere therefore acts as a giant calorimeter, whose properties need to be well known during data taking. Aerosols play a key role in this scenario, since their effect on light transmission is highly variable even on a time scale of one hour, and the corresponding correction to EAS energy can range from a few percent to more than 40%. For this reason, hourly Vertical Aerosol Optical Depth (taer(h)) profiles are provided for each of the four FD stations. Starting from 2004, up to now 9 years of taer(h) profiles have been produced using data from the Central Laser Facility (CLF) and the eXtreme Laser Facility (XLF) of the Pierre Auger Observatory. The two laser facilities, the techniques developed to measure taer(h) profiles using laser dat...

  19. Monitoring of atmospheric gamma radiation and radon observations of rainfall events in southeast of Brazil

    Science.gov (United States)

    Martin, I. M.; Alves, M. A.; Gomes, M. P.

    2013-05-01

    It is well known that we live in an environment that is under the influence of radioactivity. Radioactive elements in Earth's crust, cosmic rays, and anthropogenic sources contribute to the radiation of different types (alpha, beta, gamma and X-rays) that can be measured. An interesting phenomenon associated with environmental radioactivity is radon washout wherein the radon gas that is produced by the decay of natural radioactive elements and released into the atmosphere is concentrated near ground by falling rain. Rain drops trap radon in their interior and transport this radioactive gas to the surface. In this study, we describe the monitoring of the localized and temporary increase in the natural radioactivity caused by radon washout using a 3"x 3" NaI(Tl) scintillator. Variations in the radioactivity were correlated with changes in meteorological conditions. We observed that even though rainfall is a main factor in the increase of natural radioactivity near ground, other factors such as the presence of fog and winds play an important role in the concentration and dispersion of radon. Because of the low cost of our experimental set up, we believe that this is an experiment that could easily be conducted in most universities and could also be used to monitor environmental radioactivity levels.

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

    Science.gov (United States)

    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.

  1. Influence of complex component and particle polydispersity on radiative properties of soot aggregate in atmosphere

    International Nuclear Information System (INIS)

    The effects of morphological structure, water coating, dust mixing and primary particle size distribution on the radiative properties of soot fractal aggregates in atmosphere are investigated using T-matrix method. These fractal aggregates are numerically generated using a combination of the particle-cluster and cluster-cluster aggregation algorithms with fractal parameters representing soot aggregate in atmosphere. The radiative properties of compact aggregate notably deviate from that of the branched one, and the effect of morphology changes on the radiative properties in wet air cannot be neglected. However it is reasonable to use realization-averaged radiative properties to represent that of the aggregates with certain morphology. In wet air, the scattering, absorption and extinction cross-section and symmetry parameter of soot aggregates coated with water notably increase with water shell thickness. The mixing structures of dust have little effect on radiative properties of aggregates, but the volume fraction of dust has an obvious effect on extinction, scattering and absorption cross-section of aggregates when the size parameters are above the Rayleigh limit. Although the primary particle size distribution of soot aggregate has mild effect on the scattering albedo and asymmetry parameter, the deviations of the extinction, scattering, absorption cross-section among the three size distributions are significant in this study. The size distribution has a significant effect on forward scattering of phase function, while the effect can be neglected as the size parameter approaches to the Rayleigh limit.

  2. Measurements of pollution in the lower layers of the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Perroud, P.; Sylvestre-Baron, M.; Pleyber, G.; Perilhon, P.; Faivre- Pierret, R.; Closson, A.; Nicotra, C.

    1973-06-01

    The measurement of the meteorological parameters and the sampling of pollutants in the lower levels of the atmosphere were made by the use of captive balloons. A 550 m/sup 3/ airship filled with hydrogen was used with apparatus distributed along the anchor cable up to a height of 1,200 m. The meteorological probes used to measure the pressure, temperature, humidity, and wind velocity and to transmit them to the ground are described. The apparatus for air sampling and the chemical analytical methods are described. The results obtained are reported. This experiment made it possible to prove the relations existing between temperature inversion regions and pollution levels. The results show that under the temperature emission layers the profiles for the diffusion of SO/sub 2/, Cl/ sub 2/, and organic pollutants are sharply different. (tr-auth)

  3. Aerosol hygroscopicity and its impact on atmospheric visibility and radiative forcing in Guangzhou during the 2006 PRIDE-PRD campaign

    Science.gov (United States)

    Liu, Xingang; Zhang, Yuanhang; Cheng, Yafang; Hu, Min; Han, Tingting

    2012-12-01

    The objective of this study is to quantify the relation of aerosol chemical compositions and optical properties, and to assess the impact of relative humidity (RH) on atmospheric visibility and aerosol direct radiative forcing (ADRF). Mass concentration and size distribution of aerosol chemical compositions as well as aerosol optical properties were concurrently measured at Guangzhou urban site during the PRD (Pearl River Delta) campaign from 1 to 31 July, 2006. Gaseous pollutant NO2 and meteorological parameter were simultaneously monitored. Compared with its dry condition, atmospheric ambient extinction coefficient σext(RH) averagely increased about 51% and atmospheric visibility deceased about 35%, among which RH played an important role on the optical properties of water soluble inorganic salts. (NH4)2SO4 is the most important component responsible for visibility degradation at Guangzhou. In addition, the asymmetry factor g increased from 0.64 to 0.74 with the up-scatter fraction β decreasing from 0.24 to 0.19 when RH increasing from 40% to 90%. At 80% RH, the ADRF increased about 280% compared to that at dry condition and it averagely increased about 100% during the campaign under ambient conditions. It can be inferred that aerosol water content is a key factor and could not be ignored in assessing the role of aerosols in visibility impairment and radiative forcing, especially in the regions with high RH.

  4. Observation of hard radiations in a laboratory atmospheric high-voltage discharge

    CERN Document Server

    Agafonov, A V; Chubenko, A P; Oginov, A V; Rodionov, A A; Rusetskiy, A S; Ryabov, V A; Shepetov, A L; Shpakov, K V

    2016-01-01

    The new results concerning neutron emission detection from a laboratory high-voltage discharge in the air are presented. Data were obtained with a combination of plastic scintillation detectors and $^3$He filled counters of thermal neutrons. Strong dependence of the hard x-ray and neutron radiation appearance on the field strength near electrodes, which is determined by their form, was found. We have revealed a more sophisticated temporal structure of the neutron bursts observed during of electric discharge. This may indicate different mechanisms for generating penetrating radiation at the time formation and development of the atmospheric discharge.

  5. Kalman filtration of radiation monitoring data from atmospheric dispersion of radioactive materials

    DEFF Research Database (Denmark)

    Drews, M.; Lauritzen, B.; Madsen, H.;

    2004-01-01

    A Kalman filter method using off-site radiation monitoring data is proposed as a tool for on-line estimation of the source term for short-range atmospheric dispersion of radioactive materials. The method is based on the Gaussian plume model, in which the plume parameters including the source term...... exhibit a ‘random walk’ process. The embedded parameters of the Kalman filter are determined through maximum-likelihood estimation making the filter essentially free of external parameters. The method is tested using both real and simulated radiation monitoring data. For simulated data, the method...

  6. Analysis of atmospheric aerosols by PIXE: the importance of real time and complementary measurements

    Science.gov (United States)

    Artaxo, Paulo; Castanho, Andrea D.; Yamasoe, Marcia A.; Martins, José Vanderlei; Longo, Karla M.

    1999-04-01

    Particle-Induced X-ray Emission (PIXE) has been used for more than 30 yr in many urban and background air pollution studies. The technique has certainly contributed to the understanding of source-receptor relationship for aerosol particles as well as to aerosol physics and chemistry. In the last few years, where aerosol issues were strongly linked to global climate change through the relationship between aerosol and atmospheric radiation points to new challenges in atmospheric sciences, where PIXE could play an important role. Also the recognition for the inter-relationship between aerosol and liquid and gas phases in the atmosphere makes important to integrate PIXE aerosol analysis with other complementary measurements. The use of Nephelometers and Aethalometers to measure scattering and absorption of radiation by aerosol particles can be done in parallel with particle filter collection for PIXE analysis. Parallel measurements of trace gases using traditional monitors as well as with new techniques such as Differential Optical Absorption Spectroscopy (DOAS) that can provide concentration of O 3, SO 2, NO 3, NO 2, HCHO, HNO 3, Benzene, Toluene, and Xylene, is also important for both urban and remote aerosol studies. They provide information that allows a much richer interpretation of PIXE data. Recently developed instruments that provide real time aerosol data such as the Tapered Element Oscillating Microbalance (TEOM) PM 10 monitor and automatic real time organic and elemental carbon analyzers provide extremely useful data to complement PIXE aerosol analysis. The concentrations of trace elements measured by PIXE comprise only 10-30% of the aerosol mass, leaving the organic aerosol characterization and measurement with an important role. The aerosol source apportionment provided by PIXE analysis can be extended with other aerosol measurements such as scattering and absorption, estimating for example, the radiative impact of each discriminated aerosol source. The

  7. Comparative Experimental Investigation of Titan's Atmospheric Chemistry Driven by Solar EUV Radiation and Energetic Electron Precipitation

    Science.gov (United States)

    Imanaka, Hiroshi; Lavvas, P.; Yelle, R. V.; Smith, M. A.

    2010-10-01

    The observations by the Cassini Ion Neutral Mass Spectrometer (INMS) and the Cassini Plasma Spectrometer (CAPS) clearly demonstrate the importance of complex organic chemistry in the upper atmosphere of Titan; a complex coupling of neutral and ion chemistry for organic aerosol generation induced by EUV photons and Saturn's magnetospheric charged particles. To understand the dominant energy source for aerosol formation and its formation chemistry, we comparatively investigate the chemical mechanism in N2/CH4 gas mixtures resulting from EUV-VUV synchrotron radiation (50-150 nm) and tunable mono-energetic electron beam irradiation (5 eV - 2000 eV). These excitation energy sources cover the dominant energy source available in Titan's upper atmosphere. Our previous study of the EUV-VUV photolysis of N2/CH4 gas mixtures revealed the unique role of nitrogen photoionization in the catalytic formation of complex hydrocarbons and in the major nitrogen fixation process in Titan's upper atmosphere (Imanaka and Smith, 2007, 2009, 2010). However, relative roles of ion-molecule reactions and radical/neutral reactions in such complex chemistry remain to be determined. We characterized the electron energy distribution by conducting the Langmuir probe measurements. Degradation of the primary photoelectron from N2 photoionization at 20.6 eV photons is clearly observed, and the electron density rapidly decreases down to 109-10 cm-3, which suggests the complex coupling of ion-molecular reactions and dissociative ion-electron recombination reactions for the observed development of complex organic molecules. The electron beam irradiation experiments at energy larger than 200 eV shows distinct gaseous product distribution with nitrogenated gaseous species from those with EUV irradiation products. The generation of secondary electrons and multiple inelastic collisions of fast electrons might increases the nitrogen fixation efficiency. The much less stringent spin selection rules could

  8. Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms

    Directory of Open Access Journals (Sweden)

    S.-L. Sihto

    2006-01-01

    Full Text Available We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took place in spring 2003 in Hyytiälä (Finland. During the campaign numerous aerosol particle formation events occurred of which 15 were accompanied by gaseous sulphuric acid measurements. Our detailed analysis of these 15 events is focussed on nucleation and early growth (to a diameter of 3 nm of fresh particles. It revealed that new particle formation seems to be a function of the gaseous sulphuric acid concentration to the power from one to two when the time delay between the sulphuric acid and particle number concentration is taken into account. From the time delay the growth rates of freshly nucleated particles from 1 nm to 3 nm were determined. The mean growth rate was 1.2 nm/h and it was clearly correlated with the gaseous sulphuric acid concentration. We tested two nucleation mechanisms – recently proposed cluster activation and kinetic type nucleation – as possible candidates to explain the observed dependences, and determined experimental nucleation coefficients. We found that some events are dominated by the activation mechanism and some by the kinetic mechanism. Inferred coefficients for the two nucleation mechanisms are the same order of magnitude as chemical reaction coefficients in the gas phase and they correlate with the product of gaseous sulphuric acid and ammonia concentrations. This indicates that besides gaseous sulphuric acid also ammonia has a role in nucleation.

  9. Next-generation angular distribution models for top-of-atmosphere radiative flux calculation from the CERES instruments: methodology

    Directory of Open Access Journals (Sweden)

    W. Su

    2014-08-01

    Full Text Available The top-of-atmosphere (TOA radiative fluxes are critical components to advancing our understanding of the Earth's radiative energy balance, radiative effects of clouds and aerosols, and climate feedback. The Clouds and Earth's Radiant Energy System (CERES instruments provide broadband shortwave and longwave radiance measurements. These radiances are converted to fluxes by using scene type dependent Angular Distribution Models (ADMs. This paper describes the next-generation ADMs that are developed for Terra and Aqua using all available CERES rotating azimuth plane radiance measurements. Coincident cloud and aerosol retrievals, and radiance measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS, and meteorological parameters from Goddard Earth Observing System (GEOS data assimilation version 5.4.1 are used to define scene type. CERES radiance measurements are stratified by scene type and by other parameters that are important for determining the anisotropy of the given scene type. Anisotropic factors are then defined either for discrete intervals of relevant parameters or as a continuous functions of combined parameters, depending on the scene type. Compared to the existing ADMs, the new ADMs change the monthly mean instantaneous fluxes by up to 5 W m−2 on a regional scale of 1° latitude × 1° longitude, but the flux changes are less than 0.5 W m−2 on a global scale.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  12. Design, Construction and Calibration of a Solar Radiation Measuring Meter

    OpenAIRE

    Asiegbu, A. Daniel; Echeweozo, E. Odinakachi

    2014-01-01

    A digital solar radiation measuring instrument has been designed, constructed and calibrated. It incorporates a small rectangular silicon photocell as the sensor. On exposure to solar radiation, electromotive force which is proportional to radiation intensity is developed within the circuit. The device correlates voltage developed with available solar intensity. A standard solarimeter was therefore used to calibrate the device to translate the unit of its reading from Volt to Watt per square ...

  13. Response of biomass and nitrogen yield of white clover to radiation and atmospheric CO2 concentration

    International Nuclear Information System (INIS)

    The objectives of the present study were to test (i) whether the effect of season-long CO2 enrichment on plant dry matter production of white clover (Trifolium repens cv. Karina) depends on the temperature or can solely be explained by changes in radiation use efficiency, and (ii) whether the atmospheric CO2 concentration affects the relationship between tissue %N and plant biomass. Plants were grown in pots with adequate nutrient and water supply and were exposed to ambient and above ambient CO2 concentrations (approximately +80 ppm, +160 ppm, +280 ppm) in open-top chambers for two seasons. Nitrogen fertilizer was given only before the experiment started to promote N2 fixation. Plants were clipped to a height of 5 cm, when the canopy had reached a height of about 20 cm and when the CO2 effect had not been diminished due to self-shading of the leaves. Photon exposure (400–700 nm) measured above the canopy was linearly related to the above ground biomass, the leaf area index and the nitrogen yield (r2 > 0.94). The slopes of the curves depended on the CO2 concentration. Since most of the radiation (>90%) was absorbed by the foliage, the slopes were used to calculate the CO2 effect on the radiation use efficiency of biomass production, which is shown to increase curvilinearly between 380 and 660 ppm CO2 from 2.7 g MJ−1 to 3.9 g MJ−1. CO2 enrichment increased above ground biomass by increasing the leaf number, the individual leaf weight and the leaf area; specific leaf weight was not affected. The relative CO2 response varied between harvests; there was a slight but not significant positive relationship with mean daytime temperature. At the beginning of the season, plant nitrogen concentration in the above ground biomass was decreased by CO2 enrichment. However, at later growth stages, when the plants depended solely on N2 fixation, nitrogen concentration was found to be increased when the nitrogen concentration value was adjusted for the decrease due to the

  14. Monitoring of the atmospheric ozone layer and natural ultraviolet radiation: Annual report 2011

    Energy Technology Data Exchange (ETDEWEB)

    Svendby, T.M.; Myhre, C.L.; Stebel, K.; Edvardsen, K; Orsolini, Y.; Dahlback, A.

    2012-07-01

    This is an annual report describing the activities and main results of the monitoring programme: Monitoring of the atmospheric ozone layer and natural ultraviolet radiation for 2011. 2011 was a year with generally low ozone values above Norway. A clear decrease in the ozone layer above Norway during the period 1979-1997 stopped after 1998 and the ozone layer above Norway seems now to have stabilized.(Author)

  15. Atmospheric propagation of high power laser radiation at different weather conditions

    OpenAIRE

    Pargmann, Carsten; Hall, Thomas; Duschek, Frank; Handke, Jürgen

    2016-01-01

    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 fr...

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

    Science.gov (United States)

    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.

  17. Net-Exchange parameterization of infrared radiative transfers in Venus' atmosphere

    OpenAIRE

    Eymet, Vincent; Fournier, Richard; Dufresne, Jean-Louis; Lebonnois, Sébastien; Hourdin, Frédéric; Bullock, Mark A.

    2009-01-01

    Thermal radiation within Venus atmosphere is analyzed in close details. Prominent features are identified, which are then used to design a parameterization (a highly simplified and yet accurate enough model) to be used in General Circulation Models. The analysis is based on a net exchange formulation, using a set of gaseous and cloud optical data chosen among available referenced data. The accuracy of the proposed parameterization methodology is controlled against Monte Carlo simulations, ass...

  18. The Intergenerational Transfer of Solar Radiation Management Capabilities and Atmospheric Carbon Stocks

    OpenAIRE

    Goeschl, Timo; Heyen, Daniel; Moreno-Cruz, Juan

    2013-01-01

    Solar radiation management (SRM) technologies are considered one of the likeliest forms of geoengineering. If developed, a future generation could deploy them to limit the damages caused by the atmospheric carbon stock inherited from the current generation, despite their negative side effects. Should the current generation develop these geoengi-neering capabilities for a future generation? And how would a decision to develop SRM impact on the current generation's abatement efforts? Natural sc...

  19. Determination of atmospheric parameters to estimate global radiation in areas of complex topography: Generation of global irradiation map

    International Nuclear Information System (INIS)

    Incoming shortwave solar radiation is an important parameter in environmental applications. A detailed spatial and temporal analysis of global solar radiation on the earth surface is needed in many applications, ranging from solar energy uses to the study of agricultural, forest and biological processes. At local scales, the topography is the most important factor in the distribution of solar radiation on the surface. The variability of the elevation, the surface orientation and the obstructions due to elevations are a source of great local differences in insolation and, consequently, in other variables as ground temperature. For this reason, several models based on GIS techniques have been recently developed, integrating topography to obtain the solar radiation on the surface. In this work, global radiation is analyzed with the Solar Analyst, a model implemented on ArcView, that computes the topographic parameters: altitude, latitude, slope and orientation (azimuth) and shadow effects. Solar Analyst uses as input parameters the diffuse fraction and the transmittance. These parameters are not usually available in radiometric networks in mountainous areas. In this work, a method to obtain both parameters from global radiation is proposed. Global radiation data obtained in two networks of radiometric stations is used: one located in Sierra Magina Natural Park (Spain) with 11 stations and another one located on the surroundings of Sierra Nevada Natural Park (Spain) with 14 stations. Daily solar irradiation is calculated from a digital terrain model (DTM), the daily diffuse fraction, K, and daily atmospheric transmittivity, τ. Results provided by the model have been compared with measured values. An overestimation for high elevations is observed, whereas low altitudes present underestimation. The best performance was also reported during summer months, and the worst results were obtained during winter. Finally, a yearly global solar irradiation map has been produced

  20. Determination of atmospheric parameters to estimate global radiation in areas of complex topography: Generation of global irradiation map

    Energy Technology Data Exchange (ETDEWEB)

    Batlles, F.J.; Bosch, J.L. [Dpto. Fisica Aplicada, Universidad de Almeria, 04120 Almeria (Spain); Tovar-Pescador, J. [Dpto. Fisica, Universidad de Jaen, 23071 Jaen (Spain); Martinez-Durban, M. [Dpto. Ingenieria Lenguajes y Computacion, Universidad de Almeria, 04120 Almeria (Spain); Ortega, R. [Dpto. Edafologia y Quimica Agricola, Universidad de Almeria, 04120 Almeria (Spain); Miralles, I. [Dpto. Edafologia y Quimica Agricola, Universidad de Granada, 28071 Granada (Spain)

    2008-02-15

    Incoming shortwave solar radiation is an important parameter in environmental applications. A detailed spatial and temporal analysis of global solar radiation on the earth surface is needed in many applications, ranging from solar energy uses to the study of agricultural, forest and biological processes. At local scales, the topography is the most important factor in the distribution of solar radiation on the surface. The variability of the elevation, the surface orientation and the obstructions due to elevations are a source of great local differences in insolation and, consequently, in other variables as ground temperature. For this reason, several models based on GIS techniques have been recently developed, integrating topography to obtain the solar radiation on the surface. In this work, global radiation is analyzed with the Solar Analyst, a model implemented on ArcView, that computes the topographic parameters: altitude, latitude, slope and orientation (azimuth) and shadow effects. Solar Analyst uses as input parameters the diffuse fraction and the transmittance. These parameters are not usually available in radiometric networks in mountainous areas. In this work, a method to obtain both parameters from global radiation is proposed. Global radiation data obtained in two networks of radiometric stations is used: one located in Sierra Magina Natural Park (Spain) with 11 stations and another one located on the surroundings of Sierra Nevada Natural Park (Spain) with 14 stations. Daily solar irradiation is calculated from a digital terrain model (DTM), the daily diffuse fraction, K, and daily atmospheric transmittivity, {tau}. Results provided by the model have been compared with measured values. An overestimation for high elevations is observed, whereas low altitudes present underestimation. The best performance was also reported during summer months, and the worst results were obtained during winter. Finally, a yearly global solar irradiation map has been

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

    Science.gov (United States)

    Can, Ö.; Tegen, I.; Quaas, J.

    2015-12-01

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

  2. Measuring radiation dose to patients undergoing fluoroscopically-guided interventions

    Science.gov (United States)

    Lubis, L. E.; Badawy, M. K.

    2016-03-01

    The increasing prevalence and complexity of fluoroscopically guided interventions (FGI) raises concern regarding radiation dose to patients subjected to the procedure. Despite current evidence showing the risk to patients from the deterministic effects of radiation (e.g. skin burns), radiation induced injuries remain commonplace. This review aims to increase the awareness surrounding radiation dose measurement for patients undergoing FGI. A review of the literature was conducted alongside previous researches from the authors’ department. Studies pertaining to patient dose measurement, its formalism along with current advances and present challenges were reviewed. Current patient monitoring techniques (using available radiation dosimeters), as well as the inadequacy of accepting displayed dose as patient radiation dose is discussed. Furthermore, advances in real-time patient radiation dose estimation during FGI are considered. Patient dosimetry in FGI, particularly in real time, remains an ongoing challenge. The increasing occurrence and sophistication of these procedures calls for further advances in the field of patient radiation dose monitoring. Improved measuring techniques will aid clinicians in better predicting and managing radiation induced injury following FGI, thus improving patient care.

  3. The slant path atmospheric refraction calibrator - An instrument to measure the microwave propagation delays induced by atmospheric water vapor

    Science.gov (United States)

    Walter, Steven J.; Bender, Peter L.

    1992-01-01

    The water vapor-induced propagation delay experienced by a radio signal traversing the atmosphere is characterized by the Slant Path Atmospheric Refraction Calibrator (SPARC), which measures the difference in the travel times between an optical and a microwave signal propagating along the same atmospheric path with an accuracy of 15 picosec or better. Attention is given to the theoretical and experimental issues involved in measuring the delay induced by water vapor; SPARC measurements conducted along a 13.35-km ground-based path are presented, illustrating the instrument's stability, precision, and accuracy.

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

    Science.gov (United States)

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

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

  5. The Global Atmosphere Watch reactive gases measurement network

    Directory of Open Access Journals (Sweden)

    Martin G. Schultz

    2015-10-01

    Full Text Available Abstract Long-term observations of reactive gases in the troposphere are important for understanding trace gas cycles and the oxidation capacity of the atmosphere, assessing impacts of emission changes, verifying numerical model simulations, and quantifying the interactions between short-lived compounds and climate change. The World Meteorological Organization’s (WMO Global Atmosphere Watch (GAW program coordinates a global network of surface stations some of which have measured reactive gases for more than 40 years. Gas species included under this umbrella are ozone, carbon monoxide, nitrogen oxides, and volatile organic compounds (VOCs. There are many challenges involved in setting-up and maintaining such a network over many decades and to ensure that data are of high quality, regularly updated and made easily accessible to users. This overview describes the GAW surface station network of reactive gases, its unique quality management framework, and discusses the data that are available from the central archive. Highlights of data use from the published literature are reviewed, and a brief outlook into the future of GAW is given. This manuscript constitutes the overview of a special feature on GAW reactive gases observations with individual papers reporting on research and data analysis of particular substances being covered by the program.

  6. Comparison of analytical methods for HULIS measurements in atmospheric particles

    Directory of Open Access Journals (Sweden)

    C. Baduel

    2009-03-01

    Full Text Available Humic-Like Substances (HULIS are a major contributor to the organic carbon in atmospheric aerosol. It would be necessary to standardise an analytical method that could be easily and routinely used for HULIS measurements. We present one of the first comparisons of two of the main methods in use to extract HULIS, using i a weak anion exchanger (DEAE and ii the combination of two separation steps, one according to polarity (on C18 and the second according to acidity (with a strong anion exchanger SAX. The quantification is performed with a DOC analyzer, complemented by an investigation of the chemical structure of the extracted fractions by UV-Visible spectroscopy. The analytical performances of each method are determined and compared for humic substances standards. These methods are further applied to determine the water extractable HULIS (HULISWS and the 0.1M NaOH alkaline extractable HULIS (HULIST in atmospheric aerosol collected in an Alpine Valley during winter time. This comparison shows that the simpler DEAE isolation procedure leads to higher recoveries and better reproducibility and should therefore be recommended.

  7. An unheated permeation device for calibrating atmospheric VOC measurements

    Directory of Open Access Journals (Sweden)

    J. Brito

    2011-10-01

    Full Text Available The development of an unpowered permeation device for continuous calibration of in-situ instruments measuring atmospheric volatile organic compounds (VOCs is described. Being lightweight and compact, and containing only negligible amounts of chemicals, the device is especially suited for field use such as on board aircraft. Its speciality is to maintain the permeation process in thermal equilibrium, so that the instantaneous permeation rate can be ascribed to a simple temperature measurement. This equilibrium state is maintained by a combination of three features: (i a thin PTFE membrane as permeation medium which guarantees short stabilization times, (ii a water bath as heat buffer, and (iii a vacuum-panel based insulation, in which features (ii and (iii minimize temperature drifts to ~30 mK h−1 per Kelvin temperature difference to the environment. The respective uncertainty of the permeation rate due to thermal non-equilibrium is kept below 1%. An extensive theory part details the major permeation processes of gases through porous polymers, being Fick's diffusion, Knudsen flow, and viscous flow. Both the measured stabilization time and the measured temperature dependence of the permeation rate independently indicate that the permeation can be described by a viscous flow model, where diffusion of the gas molecules in large pores (having a diameter of >0.05 μm dominates.

  8. An unheated permeation device for calibrating atmospheric VOC measurements

    Directory of Open Access Journals (Sweden)

    J. Brito

    2011-05-01

    Full Text Available The development of an unpowered permeation device for continuous calibration of in-situ instruments measuring atmospheric volatile organic compounds (VOCs is described. Being lightweight and compact, and containing only negligible amounts of chemicals, the device is especially suited for field use such as onboard aircraft. Its speciality is to maintain the permeation process in thermal equilibrium, i.e. the instantaneous permeation rate can be ascribed via a simple temperature measurement. This equilibrium state is maintained by a combination of three features: (i a thin PTFE membrane as permeation medium which guarantees short stabilization times, (ii a water bath as heat buffer, and (iii a vacuum-panel based insulation, in which features (ii and (iii minimize temperature drifts. The uncertainty of the permeation rate due to thermal non-equilibrium is kept below 1 %. An extensive theory part details the major permeation processes of gases through porous polymers, being Fick's diffusion, Knudsen flow, and viscous flow. Both the measured stabilization time and the measured temperature dependence of the permeation rate independently indicate that the permeation can be described by a viscous flow model, where diffusion of the gas molecules in large pores (having a diameter of >0.05 μm dominates.

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

    Science.gov (United States)

    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.

  10. Chemical and physical conversion in cold atmosphere and the effect of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kulmala, M.; Aalto, P.; Korhonen, P.; Laaksonen, A.; Vesala, T. [Helsinki Univ. (Finland). Dept. of Physics

    1996-12-31

    The project is focusing on the formation and growth mechanisms of atmospheric aerosol and cloud droplets. Both aerosol particles and cloud droplets affect strongly on the atmospheric radiation fluxes by scattering and absorption. The droplet formation results from physical and chemical processes occurring simultaneously. The studies concerning the tropospheric cloud droplet formation, laboratory experiments with a cloud chamber and stratospheric cloud formation are summarized. The recent studies summarized in this presentation indicate that both aerosol particles and cloud droplets have a significant role in climatic change and ozone depletion problems. The anthropogenic emissions of gaseous and particulate pollutants change the properties of atmospheric aerosols and cloud droplets. The research in this field will be continued and more quantitative understanding based both experimental and theoretical studies is required

  11. Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large predatory fish

    DEFF Research Database (Denmark)

    Dahl, Tais Wittchen; Hammarlund, Emma U.; Anbar, Ariel D.;

    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 coi...... 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.......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...

  12. A Method of Evaluating Atmospheric Models Using Tracer Measurements.

    Science.gov (United States)

    Korain, Darko; Frye, James; Isakov, Vlad

    2000-02-01

    The authors have developed a method that uses tracer measurements as the basis for comparing and evaluating wind fields. An important advantage of the method is that the wind fields are evaluated from the tracer measurements without introducing dispersion calculations. The method can be applied to wind fields predicted by different atmospheric models or to wind fields obtained from interpolation and extrapolation of measured data. The method uses a cost function to quantify the success of wind fields in representing tracer transport. A cost function, `tracer potential,' is defined to account for the magnitude of the tracer concentration at the tracer receptors and the separation between each segment of a trajectory representing wind field transport and each of the tracer receptors. The tracer potential resembles a general expression for a physical potential because the success of a wind field trajectory is directly proportional to the magnitude of the tracer concentration and inversely proportional to its distance from this concentration. A reference tracer potential is required to evaluate the relative success of the wind fields and is defined by the initial location of any trajectory at the source. Then the method is used to calculate continuously the tracer potential along each trajectory as determined by the wind fields in time and space. Increased potential relative to the reference potential along the trajectory indicates good performance of the wind fields and vice versa. If there is sufficient spatial coverage of near and far receptors around the source, then the net tracer potential area can be used to infer the overall success of the wind fields. If there are mainly near-source receptors, then the positive tracer potential area should be used. If the vertical velocity of the wind fields is not available, then the success of the wind fields can be estimated from the vertically integrated area under the tracer potential curve. A trajectory with a maximum

  13. Atmospheric extinction in solar tower plants: absorption and broadband correction for MOR measurements

    Science.gov (United States)

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

    2015-08-01

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

  14. Atmospheric extinction in solar tower plants: absorption and broadband correction for MOR measurements

    Directory of Open Access Journals (Sweden)

    N. Hanrieder

    2015-08-01

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

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

    Science.gov (United States)

    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

  16. Measurement and Modeling of Particle Radiation in Coal Flames

    DEFF Research Database (Denmark)

    Bäckström, Daniel; Johansson, Robert; Andersson, Klas Jerker;

    2014-01-01

    properties. The in-flame particle radiation was measured with a Fourier transform infrared (FTIR) spectrometer connected to a water-cooled probe via fiber optics. In the cross-section of the flame investigated, the particles were found to be the dominating source of radiation. Apart from giving information...

  17. Baseline concept for a precise measurement of atmospheric neutrino oscillation

    Science.gov (United States)

    Aglietta, M.; Ambrosio, M.; Aprile, E.; Bologna, G.; Bonesini, M.; Bencivenni, G.; Calvi, M.; Castellina, A.; Curioni, A.; Fulgione, W.; Ghia, P. L.; Gustavino, C.; Kokoulin, R. P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Negri, P.; Paganoni, M.; Periale, L.; Petrukhin, A. A.; Picchi, P.; Pullia, A.; Ragazzi, S.; Redaelli, N.; Satta, L.; de Fatis, T. Tabarelli; Terranova, F.; Tonazzo, A.; Trinchero, G.; Vallania, P.; Villone, B.

    2000-08-01

    A high-density calorimeter, consisting of magnetized planes interleaved by Resistive Plates Chambers (RPCs, Ref. (1)) , as tracking and timing devices, is a good candidate for a new experiment on atmospheric neutrinos. With 34 kt of mass and in four years of data taking, this experiment will be sensitive to νμ→νx oscillation with Δm2>6×10-5 and large mixing, covering the region suggested by the SuperKamiokande results. Moreover, the experimental method will enable to measure the oscillation parameters from the modulation of the L/E spectrum (νμ disappearance). For >m2>3×10-3eV2, this experiment can also establish whether the oscillation occurs into a tau or a sterile neutrino, by looking for an excess of muon-less events at high energies produced by upward-going tau neutrinos(ντ appearence).

  18. Measurement of atmospheric neutrino oscillations and matter effects with PINGU

    Energy Technology Data Exchange (ETDEWEB)

    Coenders, Stefan; Euler, Sebastian; Krings, Kai; Vehring, Markus; Wallraff, Marius; Wiebusch, Christopher [RWTH Aachen Univ. (Germany). III. Physikalisches Inst.; Collaboration: IceCube-Collaboration

    2013-07-01

    With IceCube's low-energy extension DeepCore the first significant effects of atmospheric neutrino oscillations have been observed. The planned ''Precision Icecube Next Generation Upgrade'' (PINGU) inside DeepCore will lower the energy threshold to a few GeV, where matter effects of neutrino oscillations have to be taken into account. The Mikheyev-Smirnov-Wolfenstein (MSW) effect modifies the mixing between flavor and mass eigenstates of the neutrinos, resulting in stronger oscillations. Furthermore, neutrinos when passing through the Earth core experience parametric enhancement due to multiple discontinuities in the electron density. In this talk the effects of matter oscillations and the capabilities to measure these effects with PINGU are investigated.

  19. Traceability of radiation measurements: musings of a user

    International Nuclear Information System (INIS)

    Although users of radiation desire measurement traceability for a number of reasons, including legal, regulatory, contractual, and quality assurance requirements, there exists no real definition of the term in the technical literature. Definitions are proposed for both traceability and traceability to the National Bureau of Standards. The hierarchy of radiation standards is discussed and allowable uncertainties are given for each level. Areas of need with respect to radiation standards are identified, and a system of secondary radiation calibration laboratories is proposed as a means of providing quality calibrations and traceability on a routine basis

  20. Traceability of radiation measurements: musings of a user

    Energy Technology Data Exchange (ETDEWEB)

    Kathren, R.L.

    1980-04-01

    Although users of radiation desire measurement traceability for a number of reasons, including legal, regulatory, contractual, and quality assurance requirements, there exists no real definition of the term in the technical literature. Definitions are proposed for both traceability and traceability to the National Bureau of Standards. The hierarchy of radiation standards is discussed and allowable uncertainties are given for each level. Areas of need with respect to radiation standards are identified, and a system of secondary radiation calibration laboratories is proposed as a means of providing quality calibrations and traceability on a routine basis.

  1. Kalman filtration of radiation monitoring data from atmospheric dispersion of radioactive materials

    International Nuclear Information System (INIS)

    A Kalman filter method using off-site radiation monitoring data is proposed as a tool for on-line estimation of the source term for short-range atmospheric dispersion of radioactive materials. The method is based on the Gaussian plume model, in which the plume parameters including the source term exhibit a 'random walk' process. The embedded parameters of the Kalman filter are determined through maximum-likelihood estimation making the filter essentially free of external parameters. The method is tested using both real and simulated radiation monitoring data. For simulated data, the method is shown to retrieve the embedded parameters employed in generating the data and to reconstruct the plume model parameters, including the source term. When tested against experimental radiation monitoring data the method is found accurately to uncover the known source term. (authors)

  2. Measuring atmospheric naphthalene with laser-induced fluorescence

    Directory of Open Access Journals (Sweden)

    M. Martinez

    2004-01-01

    Full Text Available A new method for measuring gas-phase naphthalene in the atmosphere is based on laser-induced fluorescence at low pressure. The fluorescence spectrum of naphthalene near 308 nm was identified. Naphthalene fluorescence quenching by N2, O2 and H2O was investigated in the laboratory. No significant quenching was found for H2O with mixing ratio up to 2.5%. The quenching rate of naphthalene fluorescence is (1.98±0.18×10−11 cm3 molecule−1 s−1 for N2, and (2.48±0.08×10−10 cm3 molecule−1 s−1 for O2 at 297 K. Instrument calibrations were performed with a range of naphthalene mixing ratios between 5 and 80 parts per billion by volume (ppbv, 10−9. In the current instrument configuration, the detection limit is estimated to be about 20 parts per trillion by volume (pptv, 10−12 with 2σ confidence and a 1-min integration time. Measurement of atmospheric naphthalene in three cities, Nashville, TN, Houston, TX, and New York City, NY, are presented. Good correlation between naphthalene and major anthropogenic pollutants is found.

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

    Science.gov (United States)

    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.

  4. Deconvolution of wide field-of-view radiometer measurements of earth-emitted radiation. I - Theory

    Science.gov (United States)

    Smith, G. L.; Green, R. N.

    1981-01-01

    The theory of deconvolution of wide field-of-view (WFOV) radiometer measurements of earth-emitted radiation provides a technique by which the resolution of such measurements can be enhanced to provide radiant exitance at the top of the atmosphere with a finer resolution than the field of view. An analytical solution for the earth-emitted radiant exitance in terms of WFOV radiometer measurements is derived for the nonaxisymmetric (or regional) case, in which the measurements and radiant exitance are considered to be functions of both latitude and longitude. This solution makes it possible to deconvolve a set of WFOV radiometer measurements of earth-emitted radiation and obtain information with a finer resolution than the instantaneous field of view of the instrument. It is shown that there are tradeoffs involved in the selection between WFOV and scanning radiometers.

  5. Measurement of viscosity of gaseous mixtures at atmospheric pressure

    Science.gov (United States)

    Singh, J. J.; Mall, G. H.; Chegini, H.

    1986-01-01

    Coefficients of viscosity of various types of gas mixtures, including simulated natural-gas samples, have been measured at atmospheric pressure and room temperature using a modified capillary tube method. Pressure drops across the straight capillary tube section of a thermal mass flowmeter were measured for small, well-defined, volume flow rates for the test gases and for standard air. In this configuration, the flowmeter provides the volumetric flow rates as well as a well-characterized capillary section for differential pressure measurements across it. The coefficients of viscosity of the test gases were calculated using the reported value of 185.6 micro P for the viscosity of air. The coefficients of viscosity for the test mixtures were also calculated using Wilke's approximation of the Chapman-Enskog (C-E) theory. The experimental and calculated values for binary mixtures are in agreement within the reported accuracy of Wilke's approximation of the C-E theory. However, the agreement for multicomponent mixtures is less satisfactory, possible because of the limitations of Wilkes's approximation of the classical dilute-gas state model.

  6. Calculating isotopic fractionation from atmospheric measurements at various scales

    International Nuclear Information System (INIS)

    In this paper we describe some new approaches for calculating isotopic discrimination from atmospheric measurements of CO2 and 13C. We introduce a framework that is more flexible than the traditional 'Keeling plot' two end-member mixing model, because it allows for the explicit specification of the background values of both CO2 and 13C. This approach is necessary for evaluating time series for which one can be certain that the Keeling plot requirement of stable background is violated. We also discuss a robust method for curve fitting and for estimating uncertainty of the fitting parameters. In addition to accounting for the uncertainty associated with measurements, we also account for the uncertainty associated with the appropriateness of the analytical model to the data. Our analysis suggests that uncertainty in calculated source signatures is more strongly related to the appropriateness of the model to the data than to the analytical precision of CO2 and 13C measurements. Relative to our approach, other approaches tend to underestimate the uncertainty in the fitted parameters. There can be substantial uncertainty in slopes and intercepts (two per mil or more) even if R2 is greater than 0.98. In addition, we note that fitting methods not accounting for uncertainty in both x and y result in systematic biases in the fitted parameters. Finally, we discuss the interpretation of the apparent isotopic source signature when this is a composite of several sources

  7. Pressure transducer used for measuring close-in shock waves of nuclear explosions in the atmosphere

    International Nuclear Information System (INIS)

    This paper introduces a variable reluctance pressure transducer. It has been successfully used for the measurement of close-in shock waves of nuclear explosions in the atmosphere. This transducer's highest pressure range is 100kg/cm2 and its response rise time for all ranges is lms. It uses a specially made oil-filled pressure which allows the transducer to be able to realize underground installation. In this way, it can endure the intense nuclear radiation of nuclear explosions without losing its fast speed response characteristics. This transducer has undergone a series of environmental tests and dynamic standardizations. Therefore, it was used to measure the complete waveform of shock wave overpressure in areas near the fire ball of nuclear explosions. This paper lists the test data of a group of nuclear explosion tests

  8. Solar radiation transfer in the inhomogeneous atmosphere; Solarer Strahlungstransport in der inhomogenen Atmosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Scheirer, R.

    2001-07-01

    A most profound knowledge about the radiative characteristics of clouds is required for the development of realistic atmospheric circulation models and cloud remote sensing algorithms. At present, cloud fields are treated extremely simplified in both application areas. Cloud radiative flux parameterizations in atmospheric circulation models as well as the correlation between radiance and cloud properties as required for remote sensing algorithm are usually based on the assumption of plane-parallel homogeneous (PPHOM) clouds. Compared to realistically 3D cloud fields, this simplification leads to large systematic errors. In order to quantify these errors a Monte Carlo radiative transfer model has been developed and applied to 3D cloud fields. The latter origin from the non-hydrostatic 3D atmospheric model GESIMA. Absorption and scattering properties of the cloud particles have been calculated by means of Mie-theory for spherical water droplets and a ray-tracing code for non-spherical ice, rain, and snow particles. Line by line calculations have been used to obtain the absorption properties of the relevant atmospheric gases. (orig.) [German] Die Erstellung realistischer Zirkulationsmodelle der Atmosphaere erfordert unter Anderem eine moeglichst genaue Kenntnis der Strahlungseigenschaften von Wolken. Auch fuer Ableitung und Korrektur von Fernerkundungsalgorithmen sind die Einfluesse der Wolken auf die zu messenden Strahldichten von grosser Bedeutung. In den beiden genannten Anwendungen werden Wolkenfelder zur Zeit nur in stark vereinfachter Weise beruecksichtigt. Parameterisierungen der Strahlungsfluesse bei bewoelkter Atmosphaere in atmosphaerischen Zirkulationsmodellen, sowie die Ableitung der Zusammenhaenge zwischen Strahldichten und optischen Wolkeneigenschaften basieren auf der Annahme von planparallelen und horizontal homogenen Wolken (PPHOM). Diese Approximation kann gegenueber der dreidimensionalen Strahlungstransportberechnung (3D) zu erheblichen Fehlern

  9. Development of radiation detection and measurement systems

    International Nuclear Information System (INIS)

    This report contains descriptions on the following six items. The first item is the result of a study on CsI(TI) crystals with their light emitting characteristics and the result of a study on plastic scintillators. The second item is the result of a study on advanced radiation detectors and includes experiments for the effect of using a Compton suppressor with an HPGe detector. For the third item, we describe the results of a design work done using EGS4 for a thickness gauge, a density gauge, and a level gauge. The fourth item contains descriptions on the prototype circuit systems developed for a level gauge, a thickness gauge, and for a survey meter. The fifth part contains the computed tomography algorithm and a prototype scanning system developed for a CT system. As the sixth and the last item, we describe the prototype high precision heat source and the prototype heat-voltage converter which we have designed and fabricated

  10. Development of radiation detection and measurement systems

    Energy Technology Data Exchange (ETDEWEB)

    Moon, B. S.; Ham, C. S.; Chung, C. E. and others

    2000-03-01

    This report contains descriptions on the following six items. The first item is the result of a study on CsI(TI) crystals with their light emitting characteristics and the result of a study on plastic scintillators. The second item is the result of a study on advanced radiation detectors and includes experiments for the effect of using a Compton suppressor with an HPGe detector. For the third item, we describe the results of a design work done using EGS4 for a thickness gauge, a density gauge, and a level gauge. The fourth item contains descriptions on the prototype circuit systems developed for a level gauge, a thickness gauge, and for a survey meter. The fifth part contains the computed tomography algorithm and a prototype scanning system developed for a CT system. As the sixth and the last item, we describe the prototype high precision heat source and the prototype heat-voltage converter which we have designed and fabricated.

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

    Science.gov (United States)

    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.

  12. Radiation risk estimation based on measurement error models

    CERN Document Server

    Masiuk, Sergii; Shklyar, Sergiy; Chepurny, Mykola; Likhtarov, Illya

    2016-01-01

    This monograph discusses statistics and risk estimates applied to radiation damage under the presence of measurement errors. The first part covers nonlinear measurement error models, with a particular emphasis on efficiency of regression parameter estimators. In the second part, risk estimation in models with measurement errors is considered. Efficiency of the methods presented is verified using data from radio-epidemiological studies.

  13. Radiation quantities, units and measurements. Final report 1999

    International Nuclear Information System (INIS)

    The determination of human exposure to radiation and radioactivity, whether arising from environmental exposures, medical practice or industrial activities, requires a fundamental set of quantities and units with which exposures can be specified and the means and ability to make measurements which yield results in terms of these quantities and units. Radiation protection then, as well as effective use of radiation in medical applications, requires the capability to accurately quantify the characteristics and extent of radiation exposure, so that appropriate and useful assessments of the potential health consequences and risks, whether for protection of the public and workers or for diagnosis and treatment of disease, can be formulated. The work carried out via this concerted action on ''Radiation quantities, units and measurements'' has addressed these needs. Measurement of radiation is a complex subject and is a science in itself. Yet many users of radiation who need to make radiation measurements cannot be expected to become experts in this particular field. They need authoritative guidance on how to deal with the measurement problems connected with their particular use of radiation. The work carried out pursuant to this concerted action has resulted in publications that meet this need. Important achievements include the publication of seven new ICRU reports, the completion of all but the printing of three other ICRU reports, completion of the drafting work on two other reports, the development of many others reports and the initiation of seven new activities that will result in ICRU reports representing important future contribution to the needs identified in this project. (orig.)

  14. Collaboration between TAEA and ANASA for developing radiation measurement instruments

    International Nuclear Information System (INIS)

    Full text: Collaboration between TAEA and ANASA on the subject of 'Developing Radiation Measurement Instruments' has started by the organization of TAEA-TUDNAEM in 2002. Firstly the model NEB.300 'Dose-Rate Meter' equipped with external scintillation probe was designed and a prototype produced. Scintillation Probe of the instrument is produced by ANASA personnel, the electronics measurement circuits and other units are developed by TAEA personnel. The NEB.300 Dose-Rate Meter is a radiation meter designed to measure especially very low radiation with external scintillation probe. It has wide application range, because of its warning specification for protecting personnel working with radiation sources, and because of its measuring and monitoring specifications for surveying, evaluating and carrying the radioactive materials. Advanced micro controller technology is used to cover problems of radiation measurement. Control by micro controller enables reliable, stable measurement and display of low level dose rate fields. It makes possible the simultaneous measurement of both dose and dose rate values with scintillation detector sensitive to gamma and X-rays. Set to different dose rate or dose levels it warns audibly. Measurements are shown on the 2 1/2 digits auto range display besides other warnings

  15. Radiometric modulation measuring device of intensity of optical radiation

    Directory of Open Access Journals (Sweden)

    A. P. Yanenko

    2014-04-01

    Full Text Available Introduction. The paper proposed a block diagram of radiometric measuring the intensity of optical radiation from modulation conversion parameter input . To assess the intensity of use periodically comparing the reference signal (shaded and measurement (open photodi-odes. Studies. The proposed radiometric modulation meter provides increased sensitivity and measurement accuracy by reducing the influence of dark current measurement and reference photodiodes and compensation intrinsic noise measuring channel through their periodic anti-phase comparison.

  16. Lightning-driven inner radiation belt energy deposition into the atmosphere: implications for ionisation-levels and neutral chemistry

    OpenAIRE

    Rodger, C. J.; Enell, C.-F.; Turunen, E; M. A. Clilverd; Thomson, N. R.; Verronen, P. T.

    2007-01-01

    International audience; Lightning-generated whistlers lead to coupling between the troposphere, the Van Allen radiation belts and the lower-ionosphere through Whistler-induced electron precipitation (WEP). Lightning produced whistlers interact with cyclotron resonant radiation belt electrons, leading to pitch-angle scattering into the bounce loss cone and precipitation into the atmosphere. Here we consider the relative significance of WEP to the lower ionosphere and atmosphere by contrasting ...

  17. Effect of gamma radiation on PA 6,12 in argon atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Menchaca C, C. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca 62209, Morelos (Mexico); Martinez B, G. [Laboratorio de Investigacion y Desarrollo de Materiales Avanzados, Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Km. 12 Carretera Toluca-Atlacomulco, San Cayetano 50200, Estado de Mexico (Mexico); Alvarez C, A. [Departamento de Ingenieria Quimica y Bioquimica, Intituto Tecnologico de Zacatepec, Av. Tecnologico 27, Zacatepec 62780, Morelos (Mexico); Lara, V. H. [Departamento de Quimica, Universidad Autonoma Metropolitana, Unidad Iztapalapa, Apdo. Postal 55-534, Mexico 09340, D. F. (Mexico); Lopez V, H.; Carrasco A, H. [Departamento de Fisica de Radiaciones, ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)], e-mail: gonzomartinez02@yahoo.com.mx

    2009-07-01

    Radiation effects on crystalline fibers of PA 6,12 (nylon 6,12) gamma irradiated with {sup 6}0Co under argon atmosphere at 15 kGy, 50 kGy, 100 kGy, 200 kGy and 300 kGy were studied, covering chemical structure, morphology and surface pattern. Characterization techniques show the effect of the different doses of gamma radiation. As the doses increase, amazing behavior had been found. From thermal analysis (TGA and DTA) it is evident the decrease in melting point and in the decomposition temperatures, but the heat of fusion has a different answer to the gamma irradiation, increasing or at least remaining in the same value. These results can be related to those obtained by X-rays, which shows a an unseen behavior, with no significant differences between the spectra with the crystal size being the same for each radiation doses. Finally, , the surface pattern given by AFM and SEM confirms the physical damaged caused by the radiation doses applied. All of these changes can be attributed to the chain scission mechanism provoked by the interaction radiation-matter, which is the main cause of the oligomer formation and crystal reorganization. (Author)

  18. Validation of ozone measurements from the Atmospheric Chemistry Experiment (ACE

    Directory of Open Access Journals (Sweden)

    E. Dupuy

    2008-02-01

    Full Text Available This paper presents extensive validation analyses of ozone observations from the Atmospheric Chemistry Experiment (ACE satellite instruments: the ACE Fourier Transform Spectrometer (ACE-FTS and the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO instrument. The ACE satellite instruments operate in the mid-infrared and ultraviolet-visible-near-infrared spectral regions using the solar occultation technique. In order to continue the long-standing record of solar occultation measurements from space, a detailed quality assessment is required to evaluate the ACE data and validate their use for scientific purposes. Here we compare the latest ozone data products from ACE-FTS and ACE-MAESTRO with coincident observations from satellite-borne, airborne, balloon-borne and ground-based instruments, by analysing volume mixing ratio profiles and partial column densities. The ACE-FTS version 2.2 Ozone Update product reports more ozone than most correlative measurements from the upper troposphere to the lower mesosphere. At altitude levels from 16 to 44 km, the mean differences range generally between 0 and +10% with a slight but systematic positive bias (typically +5%. At higher altitudes (45–60 km, the ACE-FTS ozone amounts are significantly larger than those of the comparison instruments by up to ~40% (typically +20%. For the ACE-MAESTRO version 1.2 ozone data product, agreement within ±10% (generally better than ±5% is found between 18 and 40 km for the sunrise and sunset measurements. At higher altitudes (45–55 km, systematic biases of opposite sign are found between the ACE-MAESTRO sunrise and sunset observations. While ozone amounts derived from the ACE-MAESTRO sunrise occultation data are often smaller than the coincident observations (by as much as −10%, the sunset occultation profiles for ACE-MAESTRO show results that are qualitatively similar to ACE-FTS and indicate a large positive

  19. Radiation dose measurement of paediatric patients in Estonia

    Energy Technology Data Exchange (ETDEWEB)

    Kepler, K. [Training Centre of Medical Physics and Biomedical Engineering, University of Tartu (Estonia); Lintrop, M. [Department of Radiology, Tartu University Hospital, Tartu (Estonia); Servomaa, A.; Parviainen, T. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland); Eek, V.; Filippova, I. [Estonian Radiation Protection Centre, Tallinn (Estonia)

    2003-06-01

    According to the Medical Exposure Directive (97/43/Euratom) the radiation doses to patients should be measured in every hospital and doses should be compared to the reference doses established by the competent authorities. Special attention should be paid to the paediatric x-ray examinations, because the paediatric patients are more radiosensitive than adult patients. The requirement of measurements of radiation dose to patients is not yet included in the Estonian radiation act, but the purpose to join the European Communities makes the quality control in radiology very actual in Estonia. The necessity exists to introduce suitable measurement methods in the Xray departments of Estonian hospitals for establishing feedback system for radiologists, radiographers and medical physicists in optimising the radiation burden of patients and image quality. (orig.)

  20. Radiation measured for ISS-Expedition 12 with different dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, D. [Johnson Space Center-NASA, 2101 Nasa Road 1, Houston 77058 (United States); Universities Space Research Association, 2101 Nasa Parkway, Houston 77058 (United States)], E-mail: dzhou@ems.jsc.nasa.gov; Semones, E. [Johnson Space Center-NASA, 2101 Nasa Road 1, Houston 77058 (United States); Gaza, R. [Johnson Space Center-NASA, 2101 Nasa Road 1, Houston 77058 (United States); Universities Space Research Association, 2101 Nasa Parkway, Houston 77058 (United States); Johnson, S.; Zapp, N.; Weyland, M. [Johnson Space Center-NASA, 2101 Nasa Road 1, Houston 77058 (United States)

    2007-10-11

    Radiation in low Earth orbit (LEO) is mainly from Galactic Cosmic Rays (GCR), solar energetic particles and particles in South Atlantic Anomaly (SAA). These particles' radiation impact to astronauts depends strongly on the particles' linear energy transfer (LET) and is dominated by high LET radiation. It is important to investigate the LET spectrum for the radiation field and the influence of radiation on astronauts. At present, the best active dosimeters used for all LET are the tissue equivalent proportional counter (TEPC) and silicon detectors; the best passive dosimeters are thermoluminescence dosimeters (TLDs) or optically stimulated luminescence dosimeters (OSLDs) for low LET and CR-39 plastic nuclear track detectors (PNTDs) for high LET. TEPC, CR-39 PNTDs, TLDs and OSLDs were used to investigate the radiation for space mission Expedition 12 (ISS-11S) in LEO. LET spectra and radiation quantities (fluence, absorbed dose, dose equivalent and quality factor) were measured for the mission with these different dosimeters. This paper introduces the operation principles for these dosimeters, describes the method to combine the results measured by CR-39 PNTDs and TLDs/OSLDs, presents the experimental LET spectra and the radiation quantities.

  1. Radiation protection measures in the case of incidents and radiation accidents

    International Nuclear Information System (INIS)

    Measures to be taken in the case of radiation accidents connected with an unusually high radiation exposure to persons, the amounts of which exceed the limiting values, with depend on whether there has been an external or an internal exposure. In order to give further treatment in the case of whole-body or partial-body irradiation, it is necessary to estimate the exposure dose. In nuclear medicine the accident doses are generally low, i.e. acute radiation damage does not occur here, and immediate measures are not necessary. Therapeutic measures in the case of incorporation accidents are only necessary when the maximum amounts for the nuclide in question recommended by the ICRP has been reached or exceeded in the organism. However, decorporation measures ought to be carried out only by qualified radiation protection physicians. The type of radiation accident which occurs most frequently in nuclear medicine is radiation exposure as a result of contamination. If in the case of contamination of a person the measurement exceeds the radioactivity limit, the decontamination measures are necessary. In the present contribution, these measures for cases without injuries are described in detail. (orig./HP)

  2. The impact of deforestation in the Amazonian atmospheric radiative balance: a remote sensing assessment

    Directory of Open Access Journals (Sweden)

    E. T. Sena

    2012-06-01

    Full Text Available This paper addresses the Amazonian radiative budget after considering three aspects of deforestation: (i the emission of aerosols from biomass burning due to forest fires; (ii changes in surface albedo after deforestation and (iii modifications in the column water vapour amount over deforested areas. Simultaneous Clouds and the Earth's Radiant Energy System (CERES shortwave fluxes and aerosol optical depth (AOD retrievals from the Moderate Resolution Imaging SpectroRadiometer (MODIS were analysed during the peak of the biomass burning seasons (August and September from 2000 to 2009. A discrete-ordinate radiative transfer (DISORT code was used to extend instantaneous remote sensing radiative forcing assessments into 24-h averages. The mean direct radiative forcing of aerosols at the top of the atmosphere (TOA during the biomass burning season for the 10-yr studied period was −5.6 ± 1.7 W m−2. Furthermore, the spatial distribution of the direct radiative forcing of aerosols over Amazon was obtained for the biomass burning season of each year. It was observed that for high AOD (larger than 1 at 550 nm the imbalance in the radiative forcing at the TOA may be as high as −20 W m−2 locally. The surface reflectance plays a major role in the aerosol direct radiative effect. The study of the effects of biomass burning aerosols over different surface types shows that the direct radiative forcing is systematically more negative over forest than over savannah-like covered areas. Values of −15.7 ± 2.4 W m−2550 nm and −9.3 ± 1.7 W m−2550 nm were calculated for the mean daily aerosol forcing efficiencies over forest and savannah-like vegetation respectively. The overall mean annual albedo-change radiative forcing due to deforestation over the state of Rondônia, Brazil, was determined as −7.3 ± 0.9 W m−2. Biomass burning aerosols impact the radiative

  3. ISS and Space Shuttle Radiation Measurements at Solar Minimum

    Science.gov (United States)

    Gaza, Ramona; Welton, Andrew; Dunegan, Audrey; Lee, Kerry

    2011-01-01

    A summary of 2008-2011 ISS and Space Shuttle radiation dosimetry results for inside vehicle radiation monitoring in low-Earth orbit will be presented. Results include new data from ISS Expedition 22-25/20A radiation area monitors (RAM) and Shuttle Missions STS127-STS133 passive radiation dosimeters (PRD). ISS 20A radiation measurement locations included three Node 2 crew quarters locations at NOD2S5_CQ, NOD2P5_CQ and CQ-3 (Deck), as well as ESA Columbus, and JAXA Kibo locations. ISS 20A and STS127-STS133 missions were flown at 51.6 inclination with an altitude range of 330-350 km. The passive radiation results will be presented in terms of measured daily dose obtained using luminescence detectors (i.e., Al2O3:C, LiF:Mg,Ti and CaF2:Tm). In addition, preliminary results from the DOSIS 2 Project, in collaboration with the German Space Agency (DLR) will be presented. SRAG s participation to the DOSIS 2 exposure on ISS (11/16/2009-05/26/2010) involved passive radiation measurements at 10 different shielding locations inside the ESA Columbus Module.

  4. Measurement of man's exposure to external radiation

    International Nuclear Information System (INIS)

    After outlining briefly the rationale for personnel radiation monitoring with integrating detectors, a review is presented of some developments which have taken place in personnel and environmental dosimetry during the past 3.5 years. The results of a pilot field experiment concerning the stability of film and thermoluminescent dosimeters (TLDs) in four Latin-American countries are summarized. It shows that film dosimeters should be used only with caution, and in locations with a moderate climate. A survey is being conducted on the current status and trends in personnel monitoring, involving detailed questioning of over 150 laboratories in about forty countries to obtain information on the type of service and detectors, evaluation and recordkeeping, additional applications, problem and development areas, intercomparisons, practical experiences with different systems, administrative and legal aspects, etc. According to the preliminary results, the trend is away from photographic film and towards mostly automatic TLD systems, not only in the industrialized countries but also in several of the larger and more advanced developing countries. The need for higher quality standards and frequent performance tests under realistic conditions is emphasized. Differences in the requirements for personnel and

  5. Measurement of radiative widths at COMPASS

    CERN Document Server

    Krämer, Markus

    2014-01-01

    COMPASS is a multipurpose fixed-target experiment at the CERN SPS, which addresses a wide variety of physic topics, in particular the structure and spectroscopy of hadrons. Diffractive dissociation of pions on nuclear targets allows for clean access to the light meson spectrum. In addition meson production can be studied in pion-photon reactions via the Primakoff effect, where high-energetic pions react with the quasi-real photon field surrounding the target nuclei. At low pion-photon center-of-mass energies, these reactions are governed by chiral dynamics and contain information relevant for chiral perturbation theory. At higher energies, resonances are produced and their radiative coupling is investigated. During a short run using a 190GeV $\\pi^-$ beam and a lead target in the year 2004, 3 million exclusive $\\pi^-\\pi^-\\pi^+$ events in the region of small squared four-momentum transfer, i.e. t' < 0:01GeV$^2$=c$^2$, have been recorded. At very low t' < 0:001GeV$^2$=c$^2$, the contribution from electroma...

  6. A Theoretical Framework for Utilizing Long-Term Measurements of Radiation and Clouds for Solar Energy Research

    Science.gov (United States)

    Liu, Y.; Xie, Y.

    2015-12-01

    One of the greatest challenges facing solar energy research is accurately predicting global horizontal irradiance (GHI) for photovoltaic (PV) modules and direct normal irradiance (DNI) for concentrated solar power (CSP) plants at the surface with a high temporal resolution. Addressing this solar energy challenge is tied ultimately to the quantitative relationship between the direct, diffuse and total radiation reaching the surface and clouds in the atmosphere, which remains elusive. Here we will first introduce a theoretical framework that relates DNI and GHI to cloud fraction and cloud albedo through two dimensionless numbers: the relative cloud radiative forcing for the direct radiation (defined as the difference between the clear sky and all sky direct downwelling radiative fluxes normalized by the clear sky direct downwelling radiative fluxes) is primarily determined by cloud fraction; the ratio of the relative cloud radiative forcing for the total downwelling radiation to the relative cloud radiative forcing for the direct radiation is primarily determined by cloud albedo. We then use decade-long measurements of partitioned radiation and cloud properties at the ARM sites to validate the theoretical relationships between the two dimensionless radiation-based parameters and cloud properties. We will also explore the potentials and challenges of using the relationships between cloud properties and radiation partition at the surface for solar energy research, opening new avenues to utilizing ARM measurements.

  7. Radiation Environment Variations at Mars - Model Calculations and Measurements

    Science.gov (United States)

    Saganti, Premkumar; Cucinotta, Francis

    Variations in the space radiation environment due to changes in the GCR (Galactic Cosmic Ray) from the past (#23) solar cycle to the current one (#24) has been intriguing in many ways, with an unprecedented long duration of the recent solar minimum condition and a very low peak activity of the current solar maximum. Model calculated radiation data and assessment of variations in the particle flux - protons, alpha particles, and heavy ions of the GCR environment is essential for understanding radiation risk and for any future intended long-duration human exploration missions. During the past solar cycle, we have had most active and higher solar maximum (2001-2003) condition. In the beginning of the current solar cycle (#24), we experienced a very long duration of solar minimum (2009-2011) condition with a lower peak activity (2013-2014). At Mars, radiation measurements in orbit were obtained (onboard the 2001 Mars Odyssey spacecraft) during the past (#23) solar maximum condition. Radiation measurements on the surface of Mars are being currently measured (onboard the Mars Science Laboratory, 2012 - Curiosity) during the current (#24) solar peak activity (August 2012 - present). We present our model calculated radiation environment at Mars during solar maxima for solar cycles #23 and #24. We compare our earlier model calculations (Cucinotta et al., J. Radiat. Res., 43, S35-S39, 2002; Saganti et al., J. Radiat. Res., 43, S119-S124, 2002; and Saganti et al., Space Science Reviews, 110, 143-156, 2004) with the most recent radiation measurements on the surface of Mars (2012 - present).

  8. Ultra Narrowband Optical Filters for Water Vapor Differential Absorption Lidar (DIAL) Atmospheric Measurements

    Science.gov (United States)

    Stenholm, Ingrid; DeYoung, Russell J.

    2001-01-01

    Differential absorption lidar (DIAL) systems are being deployed to make vertical profile measurements of atmospheric water vapor from ground and airborne platforms. One goal of this work is to improve the technology of such DIAL systems that they could be deployed on space-based platforms. Since background radiation reduces system performance, it is important to reduce it. One way to reduce it is to narrow the bandwidth of the optical receiver system. However, since the DIAL technique uses two or more wavelengths, in this case separated by 0.1 nm, a fixed-wavelength narrowband filter that would encompass both wavelengths would be broader than required for each line, approximately 0.02 nm. The approach employed in this project is to use a pair of tunable narrowband reflective fiber Bragg gratings. The Bragg gratings are germanium-doped silica core fiber that is exposed to ultraviolet radiation to produce index-of-refraction changes along the length of the fiber. The gratings can be tuned by stretching. The backscattered laser radiation is transmitted through an optical circulator to the gratings, reflected back to the optical circulator by one of the gratings, and then sent to a photodiode. The filter reflectivities were >90 percent, and the overall system efficiency was 30 percent.

  9. Atmospheric pressure changes and unexplained variability in INR measurements.

    Science.gov (United States)

    Ernst, Michael E; Shaw, Robert F; Ernst, Erika J; Alexander, Bruce; Kaboli, Peter J

    2009-06-01

    Changes in atmospheric pressure may influence hepatic blood flow and drug metabolism. Anecdotal experience suggests international normalized ratio (INR) variability may be temporally related to significant atmospheric pressure changes. We investigated this potential association in a large sample of patients with multiple INRs. This is a retrospective review of outpatient anticoagulation records from the Iowa City Veteran's Affairs Medical Center and affiliated outpatient clinics from October 1999 to July 2007. All patients, receiving at least one prescription for warfarin and INR at least 30 days or more from the date of the first warfarin prescription, were identified. INRs during periods of hospitalization and vitamin K use were excluded. Proximity analysis using geocoding of ZIP codes of identified patients to the nearest National Oceanic and Atmospheric Administration station was performed to assign atmospheric pressure with INR. Spearman's Rho and Pearson's correlation were used to evaluate atmospheric pressure and INR. Unique patients (1441) with 45 187 INRs were analyzed. When limited to nontherapeutic INRs following a previously therapeutic INR (1121 unique patients/5256 INRs), a small but clinically insignificant association between delta INR and delta atmospheric pressure was observed (r = -0.025; P = 0.038), but not for actual INR and atmospheric pressure (P = 0.06). Delta atmospheric pressure demonstrated greater variation during fall/winter months compared with spring/summer (0.23 vs. 0.15 inHg; P atmospheric pressure changes and INR variability. These findings refute the anecdotal experience seen in our anticoagulation clinic.

  10. The definition analyses of radiation temperature measurement area

    Institute of Scientific and Technical Information of China (English)

    Fu Tairan; Cheng Xiaofang; Zhong Maohua

    2008-01-01

    In the research of primary spectrum pyrometry, this paper discussed the definition problem of radiation tem-perature measurement area based on the measurement coordinates. For the linear spectrum emissivity model and im-proved monotonic spectrum emissivity model, the characteristics of radiation temperature measurement area restricted by the measurement coordinates were theoretically analyzed, through the investigations of the temperature and emissivity co-ordinate axes. Choosing the specific primary spectrum pyrometer as an example in applications, the theoretical area of radiation temperature measurement of this pyrometer was given and it was verified through blackbody experiments. The discussions of this paper will provide the necessary foundation for the theory research development of primary spectrum pyrometry and the realization of technical applications.

  11. Upper atmospheric processes as measured by collocated Lidar, infrasound, radiometer and airglow measurements

    Science.gov (United States)

    Le Pichon, A.; Blanc, E.; Assink, J. D.; Ceranna, L.; Pilger, C.; Ross, O.; Keckhut, P.; Hauchecorne, A.; Schmidt, C.; Bittner, M.; Wuest, S.; Rüfenacht, R.; Kaempfer, N.; Smets, P.

    2013-12-01

    To better initialize weather forecasting systems, a key challenge is to understand stratosphere-resolving climate models. The ARISE project (http://arise-project.eu/) aims to design a novel infrastructure integrating different atmospheric observation networks to accurately recover the vertical structure of the wind and temperature from the ground to the mesosphere. This network includes Lidar and mesospheric airglow observations, complemented by continuous infrasound measurements. Together with additional ground-based wind radar system, such complementary techniques help to better describe the interaction between atmospheric layers from the ground to the mesosphere and the influence of large scale waves on the atmospheric dynamics. Systematic comparisons between these observations and the ECMWF upper wind and temperature models (http://www.ecmwf.int/) have been performed at the OHP site (Haute-Provence Observatory, France). The main results are outlined below. - Systematic comparisons between Lidar soundings (NDACC, http://ndacc-lidar.org/) and ECMWF highlight differences increasing with altitude. Below 50 km altitude, differences are as large as 20°K. In average, the temperature appears to be overestimated by ~5 m/s in the stratosphere and underestimated by ~10 m/s in the mesopause. - Comparisons with collocated infrasound measurements provide additional useful integrated information about the structure of the stratospheric waveguide. Below 0.5 Hz, most infrasound signals originate from ocean swells in the North Atlantic region. As expected, since most long-range propagating signals travel in the stratospheric waveguide, improved detection capability occurs downwind. Deviations from this trend are either related to short time-scale variability of the atmosphere (e.g., large-scale planetary waves, stratospheric warming effects), or can be explained by changes in the nature of the source. We investigate possible correlation between unexpected propagation paths and

  12. Field inter-comparison of eleven atmospheric ammonia measurement techniques

    Directory of Open Access Journals (Sweden)

    K. von Bobrutzki

    2009-08-01

    Full Text Available Eleven instruments for the measurement of ambient concentrations of atmospheric ammonia gas (NH3, based on eight different measurement methods were inter-compared above an intensively managed agricultural field in late summer 2008 in S. Scotland. To test the instruments over a wide range of concentrations, the field was fertilised with urea midway through the experiment, leading to an increase in the average concentration from 10 to 100 ppbv. The instruments deployed included three wet-chemistry systems, one with offline analysis (annular rotating batch denuder, RBD and two with online-analysis (Annular Denuder sampling with online Analysis, AMANDA; AiRRmonia, two Quantum Cascade Laser Absorption Spectrometers (a large-cell dual system, DUAL-QCLAS, and a compact system, c-QCLAS, two photo-acoustic spectrometers (WaSul-Flux, Nitrolux-100, a Cavity Ring Down Spectrosmeter (CRDS, a Chemical Ionisation Mass Spectrometer (CIMS, an ion mobility spectrometer (IMS and an Open-Path Fourier Transform Infra-Red (OP-FTIR spectroscopy. Each instrument was compared with each other and with the average concentration of all instruments. An overall good agreement of hourly average concentrations between the instruments (R2>0.84, was observed for NH3 concentrations at the field of up to 120 ppbv with the slopes against the average ranging from 0.67 (DUAL-QCLAS to 1.13 (AiRRmonia with intercepts of –0.74 ppbv (RBD to +2.69 ppbv (CIMS. More variability was found for performance for lower concentrations (<10 ppbv. Here the overruling factors affecting measurement precision are (a the inlet design, (b the state of inlet filters (where applicable, and (c the quality of gas-phase standards (where applicable. By reference to the fast (1 Hz instruments deployed during the study, it was possible to characterize the response times of the slower instruments.

  13. Atmospheric influences on infrared-laser signals used for occultation measurements between Low Earth Orbit satellites

    Science.gov (United States)

    Schweitzer, S.; Kirchengast, G.; Proschek, V.

    2011-10-01

    LEO-LEO infrared-laser occultation (LIO) is a new occultation technique between Low Earth Orbit (LEO) satellites, which applies signals in the short wave infrared spectral range (SWIR) within 2 μm to 2.5 μm. It is part of the LEO-LEO microwave and infrared-laser occultation (LMIO) method that enables to retrieve thermodynamic profiles (pressure, temperature, humidity) and altitude levels from microwave signals and profiles of greenhouse gases and further variables such as line-of-sight wind speed from simultaneously measured LIO signals. Due to the novelty of the LMIO method, detailed knowledge of atmospheric influences on LIO signals and of their suitability for accurate trace species retrieval did not yet exist. Here we discuss these influences, assessing effects from refraction, trace species absorption, aerosol extinction and Rayleigh scattering in detail, and addressing clouds, turbulence, wind, scattered solar radiation and terrestrial thermal radiation as well. We show that the influence of refractive defocusing, foreign species absorption, aerosols and turbulence is observable, but can be rendered small to negligible by use of the differential transmission principle with a close frequency spacing of LIO absorption and reference signals within 0.5%. The influences of Rayleigh scattering and terrestrial thermal radiation are found negligible. Cloud-scattered solar radiation can be observable under bright-day conditions, but this influence can be made negligible by a close time spacing (within 5 ms) of interleaved laser-pulse and background signals. Cloud extinction loss generally blocks SWIR signals, except very thin or sub-visible cirrus clouds, which can be addressed by retrieving a cloud layering profile and exploiting it in the trace species retrieval. Wind can have a small influence on the trace species absorption, which can be made negligible by using a simultaneously retrieved or a moderately accurate background wind speed profile. We conclude that

  14. Atmospheric influences on infrared-laser signals used for occultation measurements between Low Earth Orbit satellites

    Directory of Open Access Journals (Sweden)

    S. Schweitzer

    2011-10-01

    Full Text Available LEO-LEO infrared-laser occultation (LIO is a new occultation technique between Low Earth Orbit (LEO satellites, which applies signals in the short wave infrared spectral range (SWIR within 2 μm to 2.5 μm. It is part of the LEO-LEO microwave and infrared-laser occultation (LMIO method that enables to retrieve thermodynamic profiles (pressure, temperature, humidity and altitude levels from microwave signals and profiles of greenhouse gases and further variables such as line-of-sight wind speed from simultaneously measured LIO signals. Due to the novelty of the LMIO method, detailed knowledge of atmospheric influences on LIO signals and of their suitability for accurate trace species retrieval did not yet exist. Here we discuss these influences, assessing effects from refraction, trace species absorption, aerosol extinction and Rayleigh scattering in detail, and addressing clouds, turbulence, wind, scattered solar radiation and terrestrial thermal radiation as well. We show that the influence of refractive defocusing, foreign species absorption, aerosols and turbulence is observable, but can be rendered small to negligible by use of the differential transmission principle with a close frequency spacing of LIO absorption and reference signals within 0.5%. The influences of Rayleigh scattering and terrestrial thermal radiation are found negligible. Cloud-scattered solar radiation can be observable under bright-day conditions, but this influence can be made negligible by a close time spacing (within 5 ms of interleaved laser-pulse and background signals. Cloud extinction loss generally blocks SWIR signals, except very thin or sub-visible cirrus clouds, which can be addressed by retrieving a cloud layering profile and exploiting it in the trace species retrieval. Wind can have a small influence on the trace species absorption, which can be made negligible by using a simultaneously retrieved or a moderately accurate background wind speed profile. We

  15. Ground based measurements on reflectance towards validating atmospheric correction algorithms on IRS-P6 AWiFS data

    Science.gov (United States)

    Rani Sharma, Anu; Kharol, Shailesh Kumar; Kvs, Badarinath; Roy, P. S.

    In Earth observation, the atmosphere has a non-negligible influence on the visible and infrared radiation which is strong enough to modify the reflected electromagnetic signal and at-target reflectance. Scattering of solar irradiance by atmospheric molecules and aerosol generates path radiance, which increases the apparent surface reflectance over dark surfaces while absorption by aerosols and other molecules in the atmosphere causes loss of brightness to the scene, as recorded by the satellite sensor. In order to derive precise surface reflectance from satellite image data, it is indispensable to apply the atmospheric correction which serves to remove the effects of molecular and aerosol scattering. In the present study, we have implemented a fast atmospheric correction algorithm to IRS-P6 AWiFS satellite data which can effectively retrieve surface reflectance under different atmospheric and surface conditions. The algorithm is based on MODIS climatology products and simplified use of Second Simulation of Satellite Signal in Solar Spectrum (6S) radiative transfer code, which is used to generate look-up-tables (LUTs). The algorithm requires information on aerosol optical depth for correcting the satellite dataset. The proposed method is simple and easy to implement for estimating surface reflectance from the at sensor recorded signal, on a per pixel basis. The atmospheric correction algorithm has been tested for different IRS-P6 AWiFS False color composites (FCC) covering the ICRISAT Farm, Patancheru, Hyderabad, India under varying atmospheric conditions. Ground measurements of surface reflectance representing different land use/land cover, i.e., Red soil, Chick Pea crop, Groundnut crop and Pigeon Pea crop were conducted to validate the algorithm and found a very good match between surface reflectance and atmospherically corrected reflectance for all spectral bands. Further, we aggregated all datasets together and compared the retrieved AWiFS reflectance with

  16. Using Observations of Deep Convective Systems to Constrain Atmospheric Column Absorption of Solar Radiation in the Optically Thick Limit

    Science.gov (United States)

    Dong, Xiquan; Wielicki, Bruce A.; Xi, Baike; Hu, Yongxiang; Mace, Gerald G.; Benson, Sally; Rose, Fred; Kato, Seiji; Charlock, Thomas; Minnis, Patrick

    2008-01-01

    Atmospheric column absorption of solar radiation A(sub col) is a fundamental part of the Earth's energy cycle but is an extremely difficult quantity to measure directly. To investigate A(sub col), we have collocated satellite-surface observations for the optically thick Deep Convective Systems (DCS) at the Department of Energy Atmosphere Radiation Measurement (ARM) Tropical Western Pacific (TWP) and Southern Great Plains (SGP) sites during the period of March 2000 December 2004. The surface data were averaged over a 2-h interval centered at the time of the satellite overpass, and the satellite data were averaged within a 1 deg X 1 deg area centered on the ARM sites. In the DCS, cloud particle size is important for top-of-atmosphere (TOA) albedo and A(sub col) although the surface absorption is independent of cloud particle size. In this study, we find that the A(sub col) in the tropics is approximately 0.011 more than that in the middle latitudes. This difference, however, disappears, i.e., the A(sub col) values at both regions converge to the same value (approximately 0.27 of the total incoming solar radiation) in the optically thick limit (tau greater than 80). Comparing the observations with the NASA Langley modified Fu_Liou 2-stream radiative transfer model for optically thick cases, the difference between observed and model-calculated surface absorption, on average, is less than 0.01, but the model-calculated TOA albedo and A(sub col) differ by 0.01 to 0.04, depending primarily on the cloud particle size observation used. The model versus observation discrepancies found are smaller than many previous studies and are just within the estimated error bounds. We did not find evidence for a large cloud absorption anomaly for the optically thick limit of extensive ice cloud layers. A more modest cloud absorption difference of 0.01 to 0.04 cannot yet be ruled out. The remaining uncertainty could be reduced with additional cases, and by reducing the current

  17. Monte Carlo analysis of radiative transport in oceanographic lidar measurements

    Energy Technology Data Exchange (ETDEWEB)

    Cupini, E.; Ferro, G. [ENEA, Divisione Fisica Applicata, Centro Ricerche Ezio Clementel, Bologna (Italy); Ferrari, N. [Bologna Univ., Bologna (Italy). Dipt. Ingegneria Energetica, Nucleare e del Controllo Ambientale

    2001-07-01

    The analysis of oceanographic lidar systems measurements is often carried out with semi-empirical methods, since there is only a rough understanding of the effects of many environmental variables. The development of techniques for interpreting the accuracy of lidar measurements is needed to evaluate the effects of various environmental situations, as well as of different experimental geometric configurations and boundary conditions. A Monte Carlo simulation model represents a tool that is particularly well suited for answering these important questions. The PREMAR-2F Monte Carlo code has been developed taking into account the main molecular and non-molecular components of the marine environment. The laser radiation interaction processes of diffusion, re-emission, refraction and absorption are treated. In particular are considered: the Rayleigh elastic scattering, produced by atoms and molecules with small dimensions with respect to the laser emission wavelength (i.e. water molecules), the Mie elastic scattering, arising from atoms or molecules with dimensions comparable to the laser wavelength (hydrosols), the Raman inelastic scattering, typical of water, the absorption of water, inorganic (sediments) and organic (phytoplankton and CDOM) hydrosols, the fluorescence re-emission of chlorophyll and yellow substances. PREMAR-2F is an extension of a code for the simulation of the radiative transport in atmospheric environments (PREMAR-2). The approach followed in PREMAR-2 was to combine conventional Monte Carlo techniques with analytical estimates of the probability of the receiver to have a contribution from photons coming back after an interaction in the field of view of the lidar fluorosensor collecting apparatus. This offers an effective mean for modelling a lidar system with realistic geometric constraints. The retrieved semianalytic Monte Carlo radiative transfer model has been developed in the frame of the Italian Research Program for Antarctica (PNRA) and it is

  18. Overlapping effect of atmospheric H2O, CO2 and 03 on the CO2 radiative effect

    OpenAIRE

    Wang, Wei-Chyung; Ryan, P. Barry

    2011-01-01

    The effect of overlapping of atmospheric HThe effect of overlapping of atmospheric H2O, CO2 and 03 absorption bands on the radiation budget perturbation caused by CO2 doubling is investigated. Since the effect depends on the amount of gases in the atmosphere as well as on the strength of the absorption bands, we examine the effect associated with the variation of gas abundance using a narrow band representation for the absorption bands. This band representation allows for the absorption band ...

  19. Tomographic reconstruction of atmospheric volumes from infrared limb-imager measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ungermann, Joern

    2011-08-12

    State-of-the art nadir and limb-sounders, but also in situ measurements, do not offer the capability to highly resolve the atmosphere in all three dimensions. This leaves an observational gap with respect to small-scale structures that arise frequently in the atmosphere and that still lack a quantitative understanding. For instance, filaments and tropopause folds in the upper troposphere and lower stratosphere (UTLS) are crucial for its composition and variability. One way to achieve a highly resolved three-dimensional (3-D) picture of the atmosphere is the tomographic evaluation of limb-imager measurements. This thesis presents a methodology for the tomographic reconstruction of atmospheric constituents. To be able to deal with the large increase of observations and unknowns compared to conventional retrievals, great care is taken to reduce memory consumption and processing time. This method is used to evaluate the performance of two upcoming infrared limb-imager instruments and to prepare their missions. The first examined instrument is the infrared limb-imager on board of PREMIER (Process Exploration through Measurements of Infrared and millimetrewave Emitted Radiation), one of three remaining candidates for ESA's 7th Earth Explorer mission. Scientific goals of PREMIER are, among others, the examination of gravity waves and the quantification of processes controlling atmospheric composition in the UTLS, a region of particular importance for climate change. Simulations based on the performance requirements of this instrument deliver a vertical resolution that is slightly better than its vertical field-of-view (about 0.75 km) and a horizontal resolution of {approx}25km x 70 km. Non-linear end-to-end simulations for various gravity wave patterns demonstrate that the high 3-D resolution of PREMIER considerably extends the range of detectable gravity waves in terms of horizontal and vertical wavelength compared to previous observations. The second examined

  20. Atmospheric and land surface measurements in a prototype hydrologic observatory

    Science.gov (United States)

    Scanlon, B.; Krajewski, W.; Famiglietti, J.; Duffy, C.

    2003-12-01

    Quantifying spatial and temporal variability in fluxes across interfaces and storage within reservoirs is critical for understanding the water cycle. The interfaces being considered in this presentation on the Neuse basin prototype hydrologic observatory (HO) include the land surface - atmosphere and land surface - groundwater. Critical fluxes include precipitation, infiltration, evapotranspiration and energy balance, and groundwater recharge; soil water storage in the unsaturated zone is an important determinant of flux partitioning at either interface. A companion presentation in this session (Genereux et al.) focuses on fluxes of water and solutes related to groundwater-surface water interfaces and surface water flow. The proposed measurement approach combines remote sensing and in-situ measurements to cover a wide range in spatial (1 m2 - 10,000 km2) scales. High-resolution precipitation maps will be provided by a combination of NEXRAD data and an enhanced ground-based network of rain gauges, disdrometers, and profilers. Evapotranspiration and energy balance fluxes will be monitored at several locations to characterize spatial patterns and process controls. Measurements of water content and matric potential will be co-located in the unsaturated zone to develop in situ water retention functions and to test existing pedotransfer functions for translating basic soils data to hydraulic parameters for modeling. Subsurface water fluxes in the unsaturated zone will also be estimated using newly developed fluxmeters. Co-located unsaturated and saturated zone instrumentation will be used to measure vertical and horizontal gradients to determine flux direction and to quantify fluxes using modeling. Fluxes in the unsaturated zone below the root zone may be equated to groundwater recharge. In addition, environmental tracers (tritium/helium and chlorofluorocarbons) will be measured in groundwater to estimate recharge rates. Ground-based measurements will be located in

  1. Atmospheric correction of satellite data

    Science.gov (United States)

    Shmirko, Konstantin; Bobrikov, Alexey; Pavlov, Andrey

    2015-11-01

    Atmosphere responses for more than 90% of all radiation measured by satellite. Due to this, atmospheric correction plays an important role in separating water leaving radiance from the signal, evaluating concentration of various water pigments (chlorophyll-A, DOM, CDOM, etc). The elimination of atmospheric intrinsic radiance from remote sensing signal referred to as atmospheric correction.

  2. Harmonic analysis of the Albedo and Longwave outgoing radiation field in the system earth-atmosphere

    International Nuclear Information System (INIS)

    The data of the monthly mean values of the albedo and outgoing longwave radiation from the system earth-atmosphere were subjected to a two-dimensional harmonic analysis. The coordinates were geographical latitude and time. Harmonic coefficients were found for 71 latitudinal zones with a width of 2.50. The three-year NOAA satellite data (July 1974 - June 1977) served as primary data. The results of calculations were analyzed while grouping harmonics as follows: two groups representing independent time and space variability; the third one took into consideration the temporal spatial interdependent variability. The weight of different harmonics and groups were estimated in terms of yearly-zonal values of the variance and yearly differences in amplitudes and phases of harmonics. The accuracy of the representation of the earth-atmosphere energ balance was estimated on the basis of a few first harmonics. (author)

  3. The Meso-Structured Magnetic Atmosphere -- A Stochastic Polarized Radiative Transfer Approach

    CERN Document Server

    Carroll, T A

    2007-01-01

    We present a general radiative transfer model appropriate to diagnose the small scale and mostly unresolved magnetic field of the solar photosphere. Present modeling techniques still rely to a large extend on a-priori assumptions about the geometry of the underlying magnetic field. In an effort to obtain a more flexible and unbiased approach we pursue a rigorous statistical description of the underlying atmosphere. Based on a Markov random field model the atmospheric structures are characterized in terms of probability densities and spatial correlations. This approach allows us to derive a stochastic transport equation for polarized light valid in a regime with an arbitrary fluctuating magnetic field on finite scales. One of the key ingredients of the derived stochastic transfer equation is the correlation length which provides an additional degree of freedom to the transport equation and can therefore be used as a diagnostic parameter to estimate the characteristic length scale of the underlying magnetic fie...

  4. Measurement of atmospheric neutrino oscillations with IceCube.

    Science.gov (United States)

    Aartsen, M G; Abbasi, R; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Bechet, S; Becker Tjus, J; Becker, K-H; Bell, M; Benabderrahmane, M L; Benzvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Bertrand, D; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose, D; Böser, S; Botner, O; Brayeur, L; Bretz, H-P; Brown, A M; Bruijn, R; Brunner, J; Carson, M; Casey, J; Casier, M; Chirkin, D; Christov, A; Christy, B; Clark, K; Clevermann, F; Coenders, S; Cohen, S; Cowen, D F; Cruz Silva, A H; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Desiati, P; de With, M; DeYoung, T; Díaz-Vélez, J C; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grandmont, D T; Grant, D; Groß, A; Ha, C; Haj Ismail, A; Hallen, P; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Jagielski, K; Japaridze, G S; Jero, K; Jlelati, O; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kiryluk, J; Kislat, F; Kläs, J; Klein, S R; Köhne, J-H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Krings, K; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Leute, J; Lünemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Mészáros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Palazzo, A; Paul, L; Pepper, J A; Pérez de los Heros, C; Pfendner, C; Pieloth, D; Pinat, E; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Reimann, R; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H-G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tešić, G; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Wasserman, R; Weaver, Ch; Wellons, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zoll, M

    2013-08-23

    We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored. PMID:24010427

  5. Measurement of atmospheric neutrino oscillations with IceCube.

    Science.gov (United States)

    Aartsen, M G; Abbasi, R; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Bechet, S; Becker Tjus, J; Becker, K-H; Bell, M; Benabderrahmane, M L; Benzvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Bertrand, D; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose, D; Böser, S; Botner, O; Brayeur, L; Bretz, H-P; Brown, A M; Bruijn, R; Brunner, J; Carson, M; Casey, J; Casier, M; Chirkin, D; Christov, A; Christy, B; Clark, K; Clevermann, F; Coenders, S; Cohen, S; Cowen, D F; Cruz Silva, A H; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Desiati, P; de With, M; DeYoung, T; Díaz-Vélez, J C; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grandmont, D T; Grant, D; Groß, A; Ha, C; Haj Ismail, A; Hallen, P; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Jagielski, K; Japaridze, G S; Jero, K; Jlelati, O; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kiryluk, J; Kislat, F; Kläs, J; Klein, S R; Köhne, J-H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Krings, K; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Leute, J; Lünemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Mészáros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Palazzo, A; Paul, L; Pepper, J A; Pérez de los Heros, C; Pfendner, C; Pieloth, D; Pinat, E; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Reimann, R; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H-G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tešić, G; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Wasserman, R; Weaver, Ch; Wellons, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zoll, M

    2013-08-23

    We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored.

  6. Atmospheric and Surface Reflectance Measurements by the Geoscience Laser Altimeter System

    Science.gov (United States)

    Spinhirne, James D.; Palm, Steven P.; Hlavka, Dennis L.; Hart, William D.; Mehesh, Ashwin; Welton, Ellsworth J.

    2004-01-01

    The Geoscience Laser Altimeter System launched in early 2003 is the first satellite instrument IC space to globally observe the distribution of clouds and aerosol through laser remote sensing. The instrument is a basic backscatter lidar that operates at two wavelengths, 532 and 1064 nm. The mission data products for atmospheric observations include the calibrated, observed, attenuated backscatter cross section for cloud and aerosol; height detection for multiple cloud layers; planetary boundary layer height; cirrus and aerosol optical depth and the height distribution of aerosol and cloud scattering cross section profiles. The data will enhance knowledge in several areas of atmospheric science: the distribution, transport and influence of atmospheric aerosol, significantly more accurate measurements of the coverage and height of cirrus and other clouds, polar cloud climatology and radiation influence, the dynamics planetary boundary layer and others. An overview and summary of initial results are presented. Initial results from the first months of operation show the detailed height structure of clouds and aerosol on a global basis as expected. The 532 nm channel was expected to be the more sensitive and primary channel for aerosol measurements, but extensive aerosol loading in many regions are observed by the 1064 nm channel. Sensitivities are down to a few times l0(exp 6) l/(m-sr), much better than originally expected. The 532 channel adds an order of magnitude addition sensitivity. Initial comparisons to aerosol models have been done. Similarly for global cloud cover, good results are obtained just from the 1064 nm channel and from both channels, a measurement of multiple layers and cloud overlap has been made. Antarctica observations show high levels of total cloud cover including unique low-level cirrus and blowing snow. Data products have been generated for cloud, aerosol and PBL presence and heights in addition to the basic scattering cross section profiles.

  7. Present status of radiochromic techniques for nuclear radiation measurements

    International Nuclear Information System (INIS)

    Various developmental stages of radiochromic dosimetry in kGy to mGy range depending on its applications in radiation processing industries, radiological safety, medical sciences, nuclear or dirty bomb exposition and radiation accident have been described. Leuco dyes, pH sensitive dye with halogen containing compound and radiation induced solid state polymerization are the basic chemical methods presently in use for radiochromic techniques. The present status including achievements, limitations and R and D required for further improvements of accurate and precision measurements has also been highlighted. The reader system for mapping of radiation distributions in patient dosimetry and accurate measurements of personal doses in any nuclear or radiological accident scenario are also elaborated. (author)

  8. Application of an acoustic noise removal method to aircraft-based atmospheric temperature measurements

    Science.gov (United States)

    Hugo, Ronald J.; Nowlin, Scott R.; Hahn, Ila L.; Eaton, Frank D.; McCrae, Kim A.

    2003-01-01

    An acoustic noise removal method is used to reject engine acoustical disturbances from aircraft-based atmospheric temperature measurements. Removal of engine noise from atmospheric temperature measurements allows a larger wave number range to be fit while quantifying the magnitude of atmospheric temperature turbulence. The larger wave number range was found to result in a more statistically certain spectral slope estimate, with up to a 50% reduction in the standard deviation of measured spectral slopes. The noise removal technique was found to break down under conditions of weak atmospheric temperature turbulence where the engine acoustical disturbance can be several orders of magnitude larger than atmospheric temperature turbulence.

  9. Physical measurements for quality control in industrial radiation sterilization

    International Nuclear Information System (INIS)

    The use of ionizing radiation has brought about a growing industry for the sterilization of disposable surgical equipment, medical supplies, and containers for biological specimens. For many products, irradiation has become an alternative to autoclaving or gas treatment by ethylene oxide. Over fifteen years of experience with industrial sterilization by cobalt-60 gamma radiation have shown that radiation methods provide a clear advantage over gas sterilization, in that sterilization can be performed on non-permeable sealed packages. Moreover, regulatory agencies, such as the Food and Drug Administration in the U.S.A., are reappraising the requirements for sterility assurance. For products released to the public, consideration is now being given to the use of physical dosimetry, i.e., the measurement of radiation dose by physical methods. This is based on a knowledge of the microbial burden of the product before sterilization and on the probability of killing microorganisms by a given radiation dose. Because physical dosimetry is easier to control and less complicated than biological tests, it may be considered in the future the basis for quality assurance of the sterilized product. Some of the problems associated with standardized measurement techniques in radiation sterilization include the choice of dosimetry and its calibration, as well as methods and procedures used to minimize errors due to variations in radiation flux density, source geometry with respect to the product, and environmental factors. (author)

  10. Development of a Novel Solar Radiation Measuring Device

    OpenAIRE

    Samer Alsadi; Tamer Khatib; Sulafa Mallooh

    2012-01-01

    In this paper, a novel solar radiation measuring device is proposed. A solar cell, PIC controller, temperature sensors as well as a memory chip are used. The proposed device measures the solar radiation and the ambient temperature through a specific time period and then the measured data is stored on a memory chip through the PIC controller. After that the stored data can be transferred to a computer in order to be analyzed. However, a calibration of the used solar cell is done first, in orde...

  11. European emissions of halogenated greenhouse gases inferred from atmospheric measurements.

    Science.gov (United States)

    Keller, Christoph A; Hill, Matthias; Vollmer, Martin K; Henne, Stephan; Brunner, Dominik; Reimann, Stefan; O'Doherty, Simon; Arduini, Jgor; Maione, Michela; Ferenczi, Zita; Haszpra, Laszlo; Manning, Alistair J; Peter, Thomas

    2012-01-01

    European emissions of nine representative halocarbons (CFC-11, CFC-12, Halon 1211, HCFC-141b, HCFC-142b, HCFC-22, HFC-125, HFC-134a, HFC-152a) are derived for the year 2009 by combining long-term observations in Switzerland, Italy, and Ireland with campaign measurements from Hungary. For the first time, halocarbon emissions over Eastern Europe are assessed by top-down methods, and these results are compared to Western European emissions. The employed inversion method builds on least-squares optimization linking atmospheric observations with calculations from the Lagrangian particle dispersion model FLEXPART. The aggregated halocarbon emissions over the study area are estimated at 125 (106-150) Tg of CO(2) equiv/y, of which the hyd