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The Sloan Digital Sky Survey: Status and prospects

Description: The Sloan Digital Sky Survey (SDSS) is a project to definitively map {pi} steradians of the local Universe. An array of CCD detectors used in drift-scan mode will digitally image the sky in five passbands to a limiting magnitude of r{prime} {approximately} 23. Selected from the imaging survey, 10{sup 6} galaxies and 10{sup 5} quasars will be observed spectroscopically. I describe the current status of the survey, which is due to begin observations early in 1997, and its prospects for constraining models for dark matter in the Universe. 8 refs., 7 figs.
Date: May 1, 1996
Creator: Loveday, J. & Collaboration, SDSS
Partner: UNT Libraries Government Documents Department

Variable White Dwarf Data Tables

Description: Below, I give a brief explanation of the information in these tables. In all cases, I list the WD {number_sign}, either from the catalog of McCook {ampersand} Sion (1987) or determined by me from the epoch 1950 coordinates. Next, I list the most commonly used name (or alias), then I list the variable star designation if it is available. If not, I list the constellation name and a V** or?? depending on what the last designated variable star for that constellation is. I present epoch 2000 coordinates for all of the stars, which I precessed from the 1950 ones in most cases. I do not include proper motion effects; this is negligible for all except the largest proper motion DAV stars, such as L 19-2, BPM 37093, B 808, and G 29-38. Even in these cases, the error is no more than 30` in declination and 2 s in right ascension. I culled effective temperatures from the latest work (listed under each table); they are now much more homogeneous than before. I pulled the magnitude estimates from the appropriate paper, and they are mean values integrated over several cycles. The amplitude given is for the height of a typical pulse in the light curve. The periods correspond the dominant ones found in the light curve. In some cases, there is a band of power in a given period range, or the light curve is very complex, and I indicate this in the table. In the references, I generally list the paper with the most comprehensive pulsation analysis for the star in question. In some cases, there is more than one good reference, and I list them as well.
Date: December 31, 1997
Creator: Bradley, P. A.
Partner: UNT Libraries Government Documents Department

MULTISCALE THERMAL-INFRARED MEASUREMENTS OF THE MAUNA LOA CALDERA, HAWAII

Description: Until recently, most thermal infrared measurements of natural scenes have been made at disparate scales, typically 10{sup {minus}3}-10{sup {minus}2} m (spectra) and 10{sup 2}-10{sup 3} m (satellite images), with occasional airborne images (10{sup 1} m) filling the gap. Temperature and emissivity fields are spatially heterogeneous over a similar range of scales, depending on scene composition. A common problem for the land surface, therefore, has been relating field spectral and temperature measurements to satellite data, yet in many cases this is necessary if satellite data are to be interpreted to yield meaningful information about the land surface. Recently, three new satellites with thermal imaging capability at the 10{sup 1}-10{sup 2} m scale have been launched: MTI, TERRA, and Landsat 7. MTI acquires multispectral images in the mid-infrared (3-5{micro}m) and longwave infrared (8-10{micro}m) with 20m resolution. ASTER and MODIS aboard TERRA acquire multispectral longwave images at 90m and 500-1000m, respectively, and MODIS also acquires multispectral mid-infrared images. Landsat 7 acquires broadband longwave images at 60m. As part of an experiment to validate the temperature and thermal emissivity values calculated from MTI and ASTER images, we have targeted the summit region of Mauna Loa for field characterization and near-simultaneous satellite imaging, both on daytime and nighttime overpasses, and compare the results to previously acquired 10{sup {minus}1} m airborne images, ground-level multispectral FLIR images, and the field spectra. Mauna Loa was chosen in large part because the 4x6km summit caldera, flooded with fresh basalt in 1984, appears to be spectrally homogeneous at scales between 10{sup {minus}1} and 10{sup 2} m, facilitating the comparison of sensed temperature. The validation results suggest that, with careful atmospheric compensation, it is possible to match ground measurements with measurements from space, and to use the Mauna Loa validation site for cross-comparison of thermal infrared sensors and temperature/emissivity extraction algorithms.
Date: March 1, 2001
Creator: BALICK, L.; GILLESPIE, A. & AL, ET
Partner: UNT Libraries Government Documents Department

A study of turbulence in an evolving stable atmospheric boundary layer using large-eddy simulation

Description: A study is made of the effects of stable stratification on the fine-scale features of the flow in an evolving stable boundary layer (SBL). Large-eddy simulation (LES) techniques are used so that spatially and temporally varying and intermittent features of the turbulence can be resolved; traditional Reynolds-averaging approaches are not well suited to this. The LES model employs a subgrid turbulence model that allows upscale energy transfer (backscatter) and incorporates the effects of buoyancy. The afternoon, evening transition, and nighttime periods are simulated. Highly anisotropic turbulence is found in the developed SBL, with occasional periods of enhanced turbulence. Energy backscatter occurs in a fashion similar to that found in DNS, and is an important capability in LES of the SBL. Coherent structures are dominant in the SBL, as the damping of turbulent energy occurs more at the smaller, less organized scales.
Date: May 1, 1999
Creator: Cederwall, R & Street, R L
Partner: UNT Libraries Government Documents Department

THE SIMULATION OF FINE SCALE NOCTURNAL BOUNDARY LAYER MOTIONS WITH A MESO-SCALE ATMOSPHERIC MODEL

Description: A field project over the Atmospheric Radiation Measurement-Clouds and Radiation Testbed (ARM-CART) site during a period of several nights in September, 2007 was conducted to explore the evolution of the low-level jet (LLJ). Data was collected from a tower and a sodar and analyzed for turbulent behavior. To study the full range of nocturnal boundary layer (NBL) behavior, the Regional Atmospheric Modeling System (RAMS) was used to simulate the ARM-CART NBL field experiment and validated against the data collected from the site. This model was run at high resolution, and is ideal for calculating the interactions among the various motions within the boundary layer and their influence on the surface. The model reproduces adequately the synoptic situation and the formation and dissolution cycles of the low-level jet, although it suffers from insufficient cloud production and excessive nocturnal cooling. The authors suggest that observed heat flux data may further improve the realism of the simulations both in the cloud formation and in the jet characteristics. In a higher resolution simulation, the NBL experiences motion on a range of timescales as revealed by a wavelet analysis, and these are affected by the presence of the LLJ. The model can therefore be used to provide information on activity throughout the depth of the NBL.
Date: April 2, 2009
Creator: Werth, D.; Kurzeja, R. & Parker, M.
Partner: UNT Libraries Government Documents Department

Science & Technology Review November 2005

Description: This month's issue has the following articles: (1) A Major Advance in Understanding Metals--Commentary by Tomas Diaz de la Rubia; (2) Materials Scientists Discover the Power of ParaDiS--A new supercomputer code is revealing how metals become stronger through the formation of dislocation line junctions; (3) A Wide New Window on the Universe--Livermore scientists and engineers are contributing to the Large Synoptic Survey Telescope, which will provide unprecedented digital maps of the changing night sky; (4) Built for Speed: Graphics Processors for General-Purpose Computing--Commercial graphics processors used in the computer gaming industry are providing low-cost solutions for high-performance data processing; and (5) Negative Plasma Densities Raise Questions--Livermore physicists shed light on anomalous results in x-ray interferometry of plasmas.
Date: September 19, 2005
Creator: Aufderheide, M B
Partner: UNT Libraries Government Documents Department

Night vision device technology development

Description: This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This project sought to develop microchannel plate (MCP) technologies for enhancement of night vision device (NVD) capabilities. First, the authors addressed the need for segmented microchannel plates with independent gain control to minimize loss of low level light images in the presence of a bright light source (e.g., battlefield lasers, flares, and headlights). This would enable, for example, enhanced vision capabilities during night operations in a city environment and continuous capability of aviators to see the horizon, near-ground obstructions, and ground targets. Second, the authors addressed the need for curved microchannel plate technology to increase the field of view of NVDs while minimizing optical aberrations. This development would significantly enhance peripheral vision capabilities of aviators and result in easier adaptation of the human eye to NVDs. The authors have developed two technologies to overcome these problems, and they have initiated a collaborative effort with an industrial partner to develop a proof-of-principle prototype.
Date: December 31, 1998
Creator: Funsten, H.; Nordholt, J. & Suszcynsky, D.
Partner: UNT Libraries Government Documents Department

Improved instrumentation for near-real-time measurement of reactive hydrocarbons, NO{sub 2}, and peroxyacyl nitrates.

Description: The measurement of reactive hydrocarbons and associated nitrogen oxides, NO{sub 2}, and peroxyacyl nitrates (PANs) is of key importance to unraveling the complex chemistries involved in daytime photochemical oxidant formation and nighttime chemistry driven by the nitrate radical. Recent work has demonstrated that chemiluminescent reactions of ozone with hydrocarbons (and the temperature dependence of the reactions) can be used as a means of detecting a wide variety of organic compounds in the gas phase with sensitivity comparable to or better than that of the conventional flame ionization detection method (Marley and Gaffney, 1998). We have implemented a new design and built a new instrument to evaluate this approach for the monitoring of alkenes. This instrument makes use of a computer-controlled photon-counting system with a reaction chamber operated at room temperature. Signals are compared to those for an ethene standard to estimate relative reactivity. The instrument is described in detail here, along with a new version of a luminol-based chemiluminescence detection system with fast gas chromatography for measurement of NO{sub 2} and PANs. The photon-counting system, the reaction chamber, and the luminol detection system have been combined on one instrument rack for field use on both ground-based and aircraft platforms. Data presented show the response times of the instruments and indicate applications for examining reactive hydrocarbon emissions from both vegetation and anthropogenic sources. In addition, the luminol chemiluminescence instrument was field tested, and the data obtained are compared with data from a commercial NO{sub x} analyzer. Preliminary results demonstrating the potential use of this instrumentation for rapid measurement of key tropospheric trace species are presented and discussed.
Date: October 6, 1999
Creator: Drayton, P. J.; Blazer, C. A.; Gaffney, J. S. & Marley, N. A.
Partner: UNT Libraries Government Documents Department

Progress report of FY 1999 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

Description: Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this effort is to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. While analyzing data obtained during the Water Vapor Intensive Operating Period'97 at the SGP CART site in central Oklahoma, several questions arose about the calibration of the ARM microwave radiometers (MWR). A large portion of this years effort was a thorough analysis of the many factors that are important for the calibration of this instrument through the tip calibration method and the development of algorithms to correct this procedure. An open literature publication describing this analysis has been accepted.
Date: September 10, 1999
Creator: Westwater, Edgeworth R. & Han, Yong
Partner: UNT Libraries Government Documents Department

Progress report of FY 1998 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

Description: Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this effort is to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. The focus of this years activities has been on the intercomparison of data obtained during the Water Vapor Intensive Operating Period'97 at the SGP CART site in central Oklahoma.
Date: October 1, 1999
Creator: Westwater, Edgeworth R. & Han, Yong
Partner: UNT Libraries Government Documents Department

Progress report of FY 1997 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

Description: Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this proposal was to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. The algorithm will include recently-developed quality control procedures for radiometers. The focus of this years activities has been on the intercomparison of data obtained during an intensive operating period at the SGP CART site in central Oklahoma.
Date: October 5, 1997
Creator: Westwater, Edgeworth R. & Han, Yong
Partner: UNT Libraries Government Documents Department

RAMAN LIDAR PROFILING OF WATER VAPOR AND AEROSOLS OVER THE ARM SGP SITE.

Description: We have developed and implemented automated algorithms to retrieve profiles of water vapor mixing ratio, aerosol backscattering, and aerosol extinction from Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Raman Lidar data acquired during both daytime and nighttime operations. This Raman lidar system is unique in that it is turnkey, automated system designed for unattended, around-the-clock profiling of water vapor and aerosols (Goldsmith et al., 1998). These Raman lidar profiles are important for determining the clear-sky radiative flux, as well as for validating the retrieval algorithms associated with satellite sensors. Accurate, high spatial and temporal resolution profiles of water vapor are also required for assimilation into mesoscale models to improve weather forecasts. We have also developed and implemented routines to simultaneously retrieve profiles of relative humidity. These routines utilize the water vapor mixing ratio profiles derived from the Raman lidar measurements together with temperature profiles derived from a physical retrieval algorithm that uses data from a collocated Atmospheric Emitted Radiance Interferometer (AERI) and the Geostationary Operational Environmental Satellite (GOES) (Feltz et al., 1998; Turner et al., 1999). These aerosol and water vapor profiles (Raman lidar) and temperature profiles (AERI+GOES) have been combined into a single product that takes advantage of both active and passive remote sensors to characterize the clear sky atmospheric state above the CART site.
Date: January 9, 2000
Creator: FERRARE,R.A.
Partner: UNT Libraries Government Documents Department

Elevated stratified layers observed during VTMX.

Description: A suite of instrumentation including a minisodar, a low-frequency, single-axis sodar, a wind profiling radar and a tethersonde was used during the Vertical Transport and Mixing field study in Salt Lake City, UT, USA, to study the evolution and dynamics of stratified layers that commonly develop during nighttime. The month-long field study provided ten nights with good conditions for tethersonde flights. The real-time sodar display was used to place the tethersonde within and near the stratified layers and to make multiple transects, while atmospheric temperature, moisture, wind speed and wind direction were measured. Not surprisingly, the existence of layers with enhanced acoustic scattering correlated well with regions of potential temperature inversions; however, because wind speeds were invariably low, the Richardson number was rarely less than 0.25. The possible role of moisture in the dynamics of elevated stable layer is discussed.
Date: March 14, 2002
Creator: Coulter, R. L.; Pekour, M. S. & Martin, T. J.
Partner: UNT Libraries Government Documents Department

Planets and Stars under the Magnifying Glass

Description: Looking out to the vastness of the night sky, stargazers often ponder questions about the universe, many wondering if planets like ours can be found somewhere out there. But teasing out the details in astronomical data that point to a possible Earth-like planet is exceedingly difficult. To find an extrasolar planet--a planet that circles a star other than the Sun--astrophysicists have in the past searched for Doppler shifts, changes in the wavelength emitted by an object because of its motion. When an astronomical object moves toward an observer on Earth, the light it emits becomes higher in frequency and shifts to the blue end of the spectrum. When the object moves away from the observer, its light becomes lower in frequency and shifts to the red end. By measuring these changes in wavelength, astrophysicists can precisely calculate how quickly objects are moving toward or away from Earth. When a giant planet orbits a star, the planet's gravitational pull on the star produces a small (meters-per-second) back-and-forth Doppler shift in the star's light. Using the Doppler-shift technique, astrophysicists have identified 179 planets within the Milky Way galaxy. However, most of these are giant gas planets, similar in size to Jupiter and Saturn, and they orbit parent stars that are much closer to them than the Sun is to Earth. Planets similar in size to Earth have also been found, but they, too, are so close to their suns that they would be much hotter than Earth and too hot for life to exist. In 2005, an international collaboration of astronomers working with telescope networks throughout the Southern Hemisphere uncovered clues to a small, rocky or icy planet similar to Earth. The new planet, designated ogLE-2005-BLg-290-Lb, is the farthest planet from our solar system detected to date. The discovery was made by ...
Date: February 12, 2007
Creator: Hazi, A U
Partner: UNT Libraries Government Documents Department

A Radiometric All-Sky Infrared Camera (RASICAM) for DES/CTIO

Description: A novel radiometric all-sky infrared camera [RASICAM] has been constructed to allow automated real-time quantitative assessment of night sky conditions for the Dark Energy Camera [DECam] located on the Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile. The camera is optimized to detect the position, motion and optical depth of thin, high (8-10km) cirrus clouds and contrails by measuring their apparent temperature above the night sky background. The camera system utilizes a novel wide-field equiresolution catadioptic mirror system that provides sky coverage of 2{pi} azimuth and 14-90{sup o} from zenith. Several new technological and design innovations allow the RASICAM system to provide unprecedented cloud detection and IR-based photometricity quantification. The design of the RASICAM system is presented.
Date: August 25, 2010
Creator: Lewis, Peter M.; Rogers, Howard; Schindler, Rafe H. & /SLAC
Partner: UNT Libraries Government Documents Department

The SDSS data archive server

Description: The Sloan Digital Sky Survey (SDSS) Data Archive Server (DAS) provides public access to data files produced by the SDSS data reduction pipeline. This article discusses challenges in public distribution of data of this volume and complexity, and how the project addressed them. The Sloan Digital Sky Survey (SDSS)1 is an astronomical survey of covering roughly one quarter of the night sky. It contains images of this area, a catalog of almost 300 million objects detected in those images, and spectra of more than a million of these objects. The catalog of objects includes a variety of data on each object. These data include not only basic information but also fit parameters for a variety of models, classifications by sophisticated object classification algorithms, statistical parameters, and more. If the survey contains the spectrum of an object, the catalog includes a variety of other parameters derived from its spectrum. Data processing and catalog generation, described more completely in the SDSS Early Data Release2 paper, consists of several stages: collection of imaging data, processing of imaging data, selection of spectroscopic targets from catalogs generated from the imaging data, collection of spectroscopic data, processing of spectroscopic data, and loading of processed data into a database. Each of these stages is itself a complex process. For example, the software that processes the imaging data determines and removes some instrumental signatures in the raw images to create 'corrected frames', models the point spread function, models and removes the sky background, detects objects, measures object positions, measures the radial profile and other morphological parameters for each object, measures the brightness of each object using a variety of methods, classifies the objects, calibrates the brightness measurements against survey standards, and produces a variety of quality assurance plots and diagnostic tables. The complexity of the spectroscopic data reduction ...
Date: October 1, 2007
Creator: Neilsen, Eric H., Jr.
Partner: UNT Libraries Government Documents Department

Application of natural radionuclides for determination of tropospheric ozone and aerosol transport.

Description: Natural radionuclides have been proposed for use in assessing the transport of ozone and aerosols in the troposphere. For example, {sup 7}Be is known to be produced in the upper troposphere and lower stratosphere by interactions with cosmogenic particles. Beryllium-7 has a 53.28-day half-life and is a gamma emitter that attaches itself to fine particles in the atmosphere once it is formed. Indeed, in tropospheric aerosol samples TBe is typically found in association with aerosol particles that are 0.3 {micro}m in diameter. Some investigators have asserted that ozone from aloft can be transported into rural and urban regions during stratospheric/tropospheric folding events, leading to increased background levels of ozone. During the Texas 2000 Air Quality study, aerosol samples with a 2.5-{micro}m cutoff were collected during 12-hour cycles (day/night) for a 30-day period at the Deer Park, Texas, field site in August-September 2000. To monitor {sup 7}Be levels, high-volume samples were collected on glass fiber filters on Julian dates 225-259. Sample collection was at a field site near a city park, away from any nearby traffic. This site is under routine operation by the Texas Natural Resource Conservation Commission. Instruments operated at this same site during the study period included an ozone monitor (Dasibi), a nitrogen oxides instrument (API), a CO instrument (API), a nephelometer, a UV-B meter (Richardson-Berger), and a multifilter rotating shadow band radiometer (MFRSR, Yankee Environmental Systems). In addition, we made modified fast-response NO{sub 2} and peroxyacetyl nitrate (PAN) measurements by using a fast gas chromatography with luminol detection, to be described at this meeting (3). The results for {sup 7}Be (mBq m{sup {minus}3})are compared in Figure 1 with the maximum and average ozone values (ppb) observed at the site to identify potential correlations. In Figure 2, all of the {sup 7}Be data are plotted against the maximum ...
Date: December 6, 2000
Creator: Gaffney, J. S.; Marley, N. A.; Drayton, P. J. & Orlandini, K. A.
Partner: UNT Libraries Government Documents Department

Phoenix, Arizona, revisited : indications of aerosol effects on O{sub 3}, NO{sub 2}, UV-B, and NO{sub 3}.

Description: Fine particulate matter and tropospheric ozone levels are of concern because of their potential for health impacts, as well as their radiative effects. Both ozone and PM-2.5 standards are being exceeded in many urban and regional areas where transport and background levels can appreciably affect observed concentrations. Anthropogenic nitrogen oxides and other primary pollutant species can interact with natural organics to form secondary aerosol products via synthesis of nitric acid and its subsequent reaction with ammonia to yield ammonium nitrate. In addition, natural organics and lower-reactivity organic compounds, particularly aromatic species and monoterpenes, can generate secondary organic aerosols, both of which contribute to the formation of PM-2.5. Long-range transport and chemical transformation of hydrocarbons and NO{sub x} via both photochemical reactions and nighttime chemistry can generate significant regional levels of ozone (O{sub 3}) and other oxidants, such as peroxyacyl nitrates.
Date: September 30, 1999
Creator: Gaffney, J. S.; Marley, N. A.; Drayton, P. J.; Cunningham, M. M.; Baird, J. C.; Dintaman, J. et al.
Partner: UNT Libraries Government Documents Department

Puerto Rico - 2002 : field studies to resolve aerosol processes.

Description: A number of questions remain concerning homogeneous aerosol formation by natural organics interacting with anthropogenic pollutants. For example, chlorine has been proposed as a potential oxidant in the troposphere because of its very high reactivity with a wide range of organics (Finlayson-Pitts, 1993). Indeed, sea salt aerosol in the presence of ozone has been shown to produce chlorine atoms in heterogeneous photochemical reactions under laboratory conditions. Whether chlorine can initiate oxidation of natural organics such as monoterpene hydrocarbons and can generate homogeneous nucleation or condensable material that contributes to aerosol loadings needs to be assessed. The nighttime reactions of ozone and nitrate radical can also result in monoterpene reactions that contribute to aerosol mass. We are currently planning field studies in Puerto Rico to assess these aerosol issues and other atmospheric chemistry questions. Puerto Rico has a number of key features that make it very attractive for a field study of this sort. The principal feature is the island's very regular meteorology and its position in the Caribbean Sea relative to the easterly trade winds. This meteorology and the island's rectangular shape (100 x 35 miles) make it highly suitable for simplification of boundary layer conditions. In addition, the long stretch between Puerto Rico and the nearest pollution sources in Africa and southern Europe make the incoming background air relatively clean and constant. Furthermore, Puerto Rico has approximately 3.5 million people with a very well defined source region and a central area of rain forest vegetation. These features make Puerto Rico an ideal locale for assessing aerosol processes. The following sections describe specific areas of atmospheric chemistry that can be explored during the proposed field study.
Date: October 5, 1999
Creator: Gaffney, J. S.; Marley, N. A. & Ravelo, R.
Partner: UNT Libraries Government Documents Department

Regional-scale influences on urban air quality : a field study in Phoenix, Arizona.

Description: Regional air quality can play an important role in determining whether urban ozone or PM-2.5 standards are exceeded. Background levels of nitrogen oxide species (NO{sub x}) and their interactions with natural organics can generate secondary aerosol products via formation of nitric acid and its subsequent reaction with ammonia to form ammonium nitrate. Natural organics and reactive anthropogenic organic compounds, particularly aromatic species and monoterpenes, can also lead to the formation of secondary organic aerosols, contributing to the formation of PM-2.5. Long-range transport and chemical transformation of hydrocarbons and NO{sub x} via both photochemical reactions and nighttime chemistry can yield significant regional levels of ozone and other oxidants, such as peroxyacyl nitrates (R-C=O-O-O-NO{sub 2}; PANs). The PANs are key species in determining the apparent age of an air parcel (Gaffney et al., 1989, 1993, 1997). The most common member of the family is peroxyacetyl nitrate (R=CH3-; PAN), which typically accounts for more than 85% of the PANs found in an urban or rural site. The PANs are in equilibrium with NO{sub 2}. Peroxyacyl radicals (R-C=O-O-O) are typically produced by the photooxidation reactions of organics, particularly those of aldehyde oxidation products with OH radical during the daytime (photochemically active) periods. Proposed mechanisms for nighttime formation of PANs (Gaffney et al., 1989) include abstraction reactions of nitrate radical (NO{sub 3}) and the initiation of OH chemistry by olefin-ozone reactions.
Date: October 12, 1998
Creator: Gaffney, J. S.
Partner: UNT Libraries Government Documents Department

Prognostic atmospheric and dispersion modeling in the vicinity of Rocky Flats Plant

Description: A multiscale four-dimensional data assimilation technique is incorporated into a mesoscale model and evaluated using meteorological and tracer data collected during the Atmospheric Studies in Complex Terrain (ASCOT) field experiment in the winter of 1991. The mesoscale model is used to predict the interaction of synoptically-driven flows and small-scale circulations influenced by terrain along the Front Range in Colorado in the vicinity of the Rocky Flats Plant for four nocturnal periods during the ASCOT field experiment. Data assimilation is used to create dynamically consistent analysis fields based on the mesoscale forecasts and the special asynoptic data taken during this experiment. The wind and turbulence quantities produced by the mesoscale model are then used to determine the dispersion of a tracer released from the Rocky Flats Plant for each evening. The mesoscale model is able to qualitatively predict the mesobeta-scale drainage flows from the Front Range into the South Platte River basin; however, the largest forecast errors occurred in a region immediately adjacent to the foothills. As expected, the current data assimilation technique reduced the overall errors in the atmospheric and dispersion calculations while the model generated realistic small-scale circulations not resolved by the data. Still, the model did not capture the shallow surface drainage flows just east of the Rocky Flats Plant for two of the evenings during the field experiment.
Date: April 1, 1995
Creator: Fast, J.D.
Partner: UNT Libraries Government Documents Department

Building America Industrialized Housing Partnership (BAIHP)

Description: This final report summarizes the work conducted by the Building America Industrialized Housing Partnership (www.baihp.org) for the period 9/1/99-6/30/06. BAIHP is led by the Florida Solar Energy Center of the University of Central Florida and focuses on factory built housing. In partnership with over 50 factory and site builders, work was performed in two main areas--research and technical assistance. In the research area--through site visits in over 75 problem homes, we discovered the prime causes of moisture problems in some manufactured homes and our industry partners adopted our solutions to nearly eliminate this vexing problem. Through testing conducted in over two dozen housing factories of six factory builders we documented the value of leak free duct design and construction which was embraced by our industry partners and implemented in all the thousands of homes they built. Through laboratory test facilities and measurements in real homes we documented the merits of 'cool roof' technologies and developed an innovative night sky radiative cooling concept currently being tested. We patented an energy efficient condenser fan design, documented energy efficient home retrofit strategies after hurricane damage, developed improved specifications for federal procurement for future temporary housing, compared the Building America benchmark to HERS Index and IECC 2006, developed a toolkit for improving the accuracy and speed of benchmark calculations, monitored the field performance of over a dozen prototype homes and initiated research on the effectiveness of occupancy feedback in reducing household energy use. In the technical assistance area we provided systems engineering analysis, conducted training, testing and commissioning that have resulted in over 128,000 factory built and over 5,000 site built homes which are saving their owners over $17,000,000 annually in energy bills. These include homes built by Palm Harbor Homes, Fleetwood, Southern Energy Homes, Cavalier and the manufacturers participating in the Northwest Energy ...
Date: June 30, 2006
Creator: McIlvaine, Janet; Chandra, Subrato; Barkaszi, Stephen; Beal, David; Chasar, David; Colon, Carlos et al.
Partner: UNT Libraries Government Documents Department

Method of measuring nighttime U-values using the Mobile Window Thermal Test (MoWiTT) Facility

Description: Although primarily designed for studying the dynamic net energy flows through fenestration systems over the full diurnal cycle, the Mobile Window Thermal Test (MoWiTT) Facility is also frequently used to measure nighttime U-values. These measurements have the advantage of incorporating the exterior film coefficient resulting from the true ambient conditions at a particular time and location, rather than relying on a laboratory simulation of some assumed average or extreme condition. On the other hand, the MoWiTT is a much more complicated facility than a laboratory hot box, and the number of potential error sources is correspondingly larger. The method of deriving the nighttime U-value from directly measured data and the effect of random and systematic errors are discussed.
Date: April 1, 1992
Creator: Klems, J. H.
Partner: UNT Libraries Government Documents Department

Development of radiative-cooling materials. Final technical report: FY 1980-1981

Description: Work on research and development on glazing and selective emitter materials that will enhance day and night sky radiative cooling is described. The emphasis is on glazing development with a secondary interest in the appropriate selective emitter. The testing focused on the individual material properties. (MHR)
Date: January 1, 1981
Partner: UNT Libraries Government Documents Department