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Applications of gauge-fixed correlation functions of quarks and gluons

Description: Two uses of fixed gauge correlation functions involving quarks and gluons -- as probes of effective quark and gluon parameters and their gauge dependence and as constraints for matching coefficients -- are examined. Effective quark and gluon masses are found to decrease with increasing gauge parameter {lambda}. A fixed gauge technique is used to determine {bar s}d matching coefficients. Despite gauge variance of effective quark masses, results of this matching -- modulo statistics -- are gauge invariant. Accordingly this technique is applied to the Delta I = {1/2} Rule. We are however unable to obtain physically useful results at present in this case because of large fluctuations. 17 refs., 5 figs.
Date: December 1, 1990
Creator: Bernard, C. (California Univ., Santa Barbara, CA (USA). Inst. for Theoretical Physics); Soni, A. (California Univ., Santa Barbara, CA (USA). Inst. for Theoretical Physics Brookhaven National Lab., Upton, NY (USA)) & Yee, K. (Brookhaven National Lab., Upton, NY (USA))
Partner: UNT Libraries Government Documents Department

The behavior of matter under nonequilibrium conditions: Fundamental aspects and applications. Progress Report for period April 15, 1990 - April 14, 1991

Description: Our report contains a brief summary of what has been achieved over the period of the contract. We have studied the behavior of matter under equilibrium conditions on three levels: (1) on the microscopic level in the frame of classical mechanics or of quantum theory; (2) on the stochastic level, which includes fluctuations; and (3) on the phenomenological, macroscopic level described by nonlinear equations. We first report on the level (1), then report on the levels (2) and (3).
Date: December 1, 1990
Creator: Prigogine, I.
Partner: UNT Libraries Government Documents Department

Classification of hydrostratigraphic units at the Savannah River Site, South Carolina

Description: A detailed synthesis of the hydrologic, geophysical and core data from wells penetrating the updip Mesozoic-Cenozoic Coastal Plain sequence at and near the Savannah River Site (SRS) was conducted to define and classify the hydrostratigraphic units. The purpose of the study was to give the SRS a single unified hydrostratigraphic classification that defines and addresses the hydrogeologic characteristics of the aquifers underlying the site. The characterization, areal distribution and classification of the aquifer and aquifer systems gives SRS the tools to evaluate ground water movement and contaminant transport in a comprehensive regional context. An alpha-numeric nomenclature has been temporarily adopted in this report for classifying the aquifers and aquifer systems at SRS. Formal geographic names for the aquifers and aquifer systems will be proposed in the near future but must be agreed upon and ratified by the South Carolina Hydrostratigraphic Subcommittee which was in part organized for the purpose. The classification utilizes a hierarchy of terms ranked at three levels: Aquifer Systems that transmit ground water regionally; Aquifer Units which are mappable units > 400 square miles in area; and Aquifer Zones that differentiate aquifers internally on the basis of locally significant characteristics.
Date: December 1, 1990
Creator: Aadland, R.K. & Bledsoe, H.W.
Partner: UNT Libraries Government Documents Department

Classification of hydrostratigraphic units at the Savannah River Site, South Carolina

Description: A detailed synthesis of the hydrologic, geophysical and core data from wells penetrating the updip Mesozoic-Cenozoic Coastal Plain sequence at and near the Savannah River Site (SRS) was conducted to define and classify the hydrostratigraphic units. The purpose of the study was to give the SRS a single unified hydrostratigraphic classification that defines and addresses the hydrogeologic characteristics of the aquifers underlying the site. The characterization, areal distribution and classification of the aquifer and aquifer systems gives SRS the tools to evaluate ground water movement and contaminant transport in a comprehensive regional context. An alpha-numeric nomenclature has been temporarily adopted in this report for classifying the aquifers and aquifer systems at SRS. Formal geographic names for the aquifers and aquifer systems will be proposed in the near future but must be agreed upon and ratified by the South Carolina Hydrostratigraphic Subcommittee which was in part organized for the purpose. The classification utilizes a hierarchy of terms ranked at three levels: Aquifer Systems that transmit ground water regionally; Aquifer Units which are mappable units > 400 square miles in area; and Aquifer Zones that differentiate aquifers internally on the basis of locally significant characteristics.
Date: December 1, 1990
Creator: Aadland, R. K. & Bledsoe, H. W.
Partner: UNT Libraries Government Documents Department

Confirming the Lanchestrian linear-logarithmic model of attrition

Description: This paper is the fourth in a series of reports on the breakthrough research in historical validation of attrition in conflict. Significant defense policy decisions, including weapons acquisition and arms reduction, are based in part on models of conflict. Most of these models are driven by their attrition algorithms, usually forms of the Lanchester square and linear laws. None of these algorithms have been validated. The results of this paper confirm the results of earlier papers, using a large database of historical results. The homogeneous linear-logarithmic Lanchestrian attrition model is validated to the extent possible with current initial and final force size data and is consistent with the Iwo Jima data. A particular differential linear-logarithmic model is described that fits the data very well. A version of Helmbold's victory predicting parameter is also confirmed, with an associated probability function. 37 refs., 73 figs., 68 tabs.
Date: December 1, 1990
Creator: Hartley, D.S. III.
Partner: UNT Libraries Government Documents Department

Microwave reflectometry for the study of density fluctuations in tokamak plasmas

Description: The effect of small scale density fluctuations on the propagation of electromagnetic waves in an inhomogeneous magnetized plasma in the presence of a cutoff is investigated. It is shown that, provided the fluctuation scale length is greater than the free space wavelength of an incident plane wave, the scattered field is strongly enhanced from fluctuations near the turning point. Numerical results for wave propagation in a tokamak plasma demonstrate the feasibility of reflectometry for the localized measurement of density fluctuations in the range k {sub {perpendicular}} {rho}{sub i} {much lt} 1. 19 refs., 6 figs,
Date: December 1, 1990
Creator: Mazzucato, E. & Nazikian, R.
Partner: UNT Libraries Government Documents Department

Nonlinear theory of trapped electron temperature gradient driven turbulence in flat density H-mode plasmas

Description: Ion temperature gradient turbulence based transport models have difficulties reconciling the recent DIII-D H-mode results where the density profile is flat, but {chi}{sub e} > {chi}{sub i} in the core region. In this work, a nonlinear theory is developed for recently discovered ion temperature gradient trapped electron modes propagating in the electron diamagnetic direction. This instability is predicted to be linearly unstable for L{sub Ti}/R {approx lt} {kappa}{sub {theta}}{rho}{sub s} {approx lt} (L{sub Ti}/R){sup 1/4}. They are also found to be strongly dispersive even at these long wavelengths, thereby suggesting the importance of the wave-particle-wave interactions in the nonlinear saturation phase. The fluctuation spectrum and anomalous fluxes are calculated. In accordance with the trends observed in DIII-D, the predicted electron thermal diffusivity can be larger than the ion thermal diffusivity. 17 refs., 3 figs.
Date: December 1, 1990
Creator: Hahm, T.S.
Partner: UNT Libraries Government Documents Department

Review of recent stellarator results in the USA, the USSR, and Japan

Description: Stellarators with significant magnetic shear in the United States, the Soviet Union, and Japan are described, and recent results are discussed in terms of their contributions to the physics understanding relevant for stellarator optimization and to toroidal confinement understanding in general. The areas discussed are the properties of stellarators with significant shear, magnetic surfaces, trapped-particle losses, magnetohydrodynamic (MHD) stability, global confinement scaling, local transport, fluctuations, and particle and impurity control. 58 refs., 23 figs.
Date: December 1, 1990
Creator: Lyon, J.F.
Partner: UNT Libraries Government Documents Department

Advanced development of particle beam probe diagnostic systems

Description: This progress report covers the period starting with the approval to go ahead with the 2 MeV heavy ion beam probe (HIBP) for TEXT Upgrade to the submission of the grant renewal proposal. During this period the co-principal investigators, R. L. Hickok and T. P. Crowley have each devoted 45% of their time to this Grant. Their effort has been almost exclusively devoted to the design and fabrication of the 2 MeV HIBP system. The 1989 report that described the advantages of a 2 MeV HIBP for TEXT Upgrade compared to the existing 0.5 MeV HIBP and outlined the design of the 2 MeV system is attached as Appendix A. Since the major effort under the renewal proposal will be the continued fabrication, installation and operation of the 2 MeV system on TEXT Upgrade, we describe some of the unique results that have been obtained with the 0.5 MeV system on TEXT. For completeness, we also include the preliminary operation of the 160 keV HIBP on ATF. We present the present fabrication status of the 2 MeV system with the exception of the electrostatic energy analyzer. The energy analyzer which is designed to operate with 400 kV on the top plate is a major development effort and is treated separately. Included in this section are the results obtained with a prototype no guard ring analyzer, the conceptual design for the 2 MeV analyzer, the status of the high voltage testing of full size analyzer systems and backup plans if it turns out that it is impossible to hold 400 kV on an analyzer this size.
Date: November 1, 1990
Creator: Hickok, R.L.; Crowley, T.P. & Connor, K.A.
Partner: UNT Libraries Government Documents Department

Evaluation of Hanford site water-table changes, 1980--1990

Description: Irrigation applied west of the Hanford Site and wastewater management practices on the Hanford Site resulted in significant changes in the configuration of the water table between December 1979 and December 1989. In the Cold Creek Valley, located in the western part of the Hanford Site, the water table rose more than 3 m (9 ft) between December 1979 and December 1989. Since 1969, the water table in the Cold Creek Valley has been rising, primarily in response to irrigation practices in the Upper Cold Creek Valley. The largest areal changes have occurred in the vicinity of production facilities in the 200 Areas where ground-water mounds have developed since operations began in 1943. During the 1940s and 1950s, two ground-water mounds developed as a result of wastewater management practices in the 200 Areas, one beneath 216-U-10 Pond in the 200-West Area and one beneath 216-B-3 Pond near the 200-East Area. During the 1960s, the ground-water mounds grew moderately before reaching near-equilibrium conditions during the 1970s. During the 1980s (December 1979 to December 1989), stresses imposed on the unconfined aquifer caused recurrence of unsteady state conditions. In the 200-West Area, the water level declined more than 2.5 m (8 ft) between December 1979 and 1989. Most of the decline occurred after 1984, which correlates with a reduction in wastewater discharge caused by the decommissioning of 216-U-10 Pond in 1984. The decline in the water table occurred mostly in the area between the 200-West Area and the Yakima Ridge basalt, which outcrops above the water table to the south of the 200-West Area. 50 refs., 31 figs., 1 tab.
Date: November 1, 1990
Creator: Newcomer, D.R.
Partner: UNT Libraries Government Documents Department

Experimental studies of plasma fluctuations using electron cyclotron emission on ATF (Advanced Toroidal Facility) and TEXT (Texas Experimental Tokamak)

Description: The great stumbling block in the quest for fusion power using magnetic confinement devices is anomalous transport. It is conjectured that turbulent plasma fluctuations may be responsible for the degraded energy confinement observed in experiments. There exists a clear need for more detailed experimental studies of plasma microturbulence. We have started a set of experiments to measure electron temperature and density fluctuations using electron cyclotron emission (ECE). The ECE systems will employ auto-correlation and cross-correlation techniques to measure radiation from the Advanced Toroidal Facility at Oak Ridge National Laboratory (ORNL) and also from the Texas Experimental Tokamak (TEXT) at the University of Texas. This set of experiments on a stellerator and a tokamak will allow a unique comparative study of the fluctuation physics in the two different magnetic configurations. This work is in support of the United States Department of Energy Tokamak Transport Initiative and involves a collaborative effort between Auburn University, Georgia Institute of Technology, the University of Texas at Austin and ORNL. 3 refs.
Date: November 1, 1990
Creator: Gandy, R.
Partner: UNT Libraries Government Documents Department

Interseasonal air-sea interactions in the OSU (Oregon State University) coupled upper ocean-atmosphere GCM (general circulation model)

Description: In this paper we examine the climatology of some variables which play an important role in the generation of low frequency variability in the Oregon State University coupled upper ocean-atmosphere general circulation model (GCM). The atmospheric model, representing the troposphere, consists of two equal mass layers between the surface and 200mb. The ocean model, developed by Pollard (1982), consists of two variable depth layers crudely representing the mixed layer and thermocline which overlie deep quiescent water. Entrainment between the upper two layers is parameterized according to the turbulent kinetic energy budget method of Niiler and Kraus (1977). Both ocean and atmospheric GCMs have a resolution of four degrees in latitude and five degrees in longitude. Here we examine the interseasonal variation of thermocline depth (sum of the two variable depth upper layers), mixed layer currents, and surface winds from the last 23 years of a 25-year control integration of this coupled model. 5 refs., 2 figs., 1 tab.
Date: November 1, 1990
Creator: Sperber, K.R.; Gates, W.L.; Potter, G.L. (Lawrence Livermore National Lab., CA (USA)) & Hameed, S. (State Univ. of New York, Stony Brook, NY (USA). Inst. for Terrestrial and Planetary Atmospheres)
Partner: UNT Libraries Government Documents Department

Kinetic studies of anomalous transport

Description: Progress in achieving a physics-based understanding of anomalous transport in toroidal systems has come in large part from investigations based on the proposition that low frequency electrostatic microinstabilities are dominant in the bulk ( confinement'') region of these plasmas. Although the presence here of drift-type modes dependent on trapped particle and ion temperature gradient driven effects appears to be consistent with a number of important observed confinement trends, conventional estimates for these instabilities cannot account for the strong current (I{sub p}) and /or q-scaling frequently found in empirically deduced global energy confinement times for auxiliary-heated discharges. The present paper deals with both linear and nonlinear physics features, ignored in simpler estimates, which could introduce an appreciable local dependence on current. It is also pointed out that while the thermal flux characteristics of drift modes have justifiably been the focus of experimental studies assessing their relevance, other transport properties associated with these microinstabilities should additionally be examined. Accordingly, the present paper provides estimates and discusses the significance of anomalous energy exchange between ions and electrons when fluctuations are present. 19 refs., 3 figs.
Date: November 1, 1990
Creator: Tang, W.M.
Partner: UNT Libraries Government Documents Department

Photon resonance spectroscopy

Description: This report summarizes the progress on Grant No. FG05-87ER40353 during the period February 1, 1990 to November 30, 1990. The primary focus of the research during this period has been on fluctuations of nuclear levels and possible connections with fundamental symmetries. In this paper the analysis of low-lying nuclear levels for a large collection of nuclides is discussed, and the analysis of just the levels in {sup 116}Sn is presented. The current status experiments to study fluctuation properties in {sup 30}P is summarized, while the development of hardware and software for the next phase of these measurements in outlined. We discuss the early stages of a project to search for a particular type of detailed-balance violation.
Date: November 1, 1990
Creator: Shriner, J.F. Jr.
Partner: UNT Libraries Government Documents Department

A scoping study of water table excursions induced by seismic and volcanic events

Description: We develop conservative models of water table response to displacements just beneath the water table simulating (1) shallow intrusion of a dike and (2) high level slip on a normal fault locked at the end. For matrix flow, we fine local water table excursions of under 10 m. in cases of isotropic permeability which includes dike inflation of 4 m and fault slips corresponding to earthquakes having a moment magnitude of 7.4. Even for enhancements of vertical permeability up to 10{sup 4}:1, excursions did not exceed 15 m which implies that pumping is strongly volume limited. We also present an analysis of upward directed flow in cracks for the case of earthquake induced pore pressure changes. For matrix properties characteristic of the Calico Hills (vitric) formation and a crack distribution bounding the potential flow capacity of published data, we estimate an upper bound of 0.25 cu m. of ground water per m. of fault length as the amount capable of being pumped to a level 250 m. above the normal water table. While the presence of even larger fractures than assumed might carry more ground water to that level an absolute upper limit of less than 50 cu. m. per m. of fault length is available to be pumped assuming a value n=0.46 for the rock porosity. For less porous rocks typical of the Topopah Spring or Tiva Canyon formations (n{approx}0.10) the upper limit may be reduced to less than 10 cu. m. per m. of fault length. This upper limit depends only upon strain, the height of pumping above the water table and the formation porosity.
Date: November 1, 1990
Creator: Carrigan, C.R.; King, G.C.P. & Barr, G.E.
Partner: UNT Libraries Government Documents Department

Stability and performance of CDRL-FEL (Chemical Dynamics Research Laboratory-Free Electron Laser)

Description: We study the performance of a proposed infrared free electron laser at Lawrence Berkeley Laboratory, which would be a user facility and therefore has a unique set of requirements in intensity, spectrum and stability. The output performance in intensity and spectrum, and methods to optimize the performance, are studied in detail. The effect of the electron beam fluctuation on FEL stability is carefully evaluated to set a tolerance for the accelerator design. Use of intracavity gratings is studied as a means of further improving the spectral purity and stability. 19 refs., 12 figs., 2 tabs.
Date: November 1, 1990
Creator: Kim, K.J. & Xie, M.
Partner: UNT Libraries Government Documents Department

Stochastic inflation lattice simulations: Ultra-large scale structure of the universe

Description: Non-Gaussian fluctuations for structure formation may arise in inflation from the nonlinear interaction of long wavelength gravitational and scalar fields. Long wavelength fields have spatial gradients {alpha}{sup {minus}1} {triangledown} small compared to the Hubble radius, and they are described in terms of classical random fields that are fed by short wavelength quantum noise. Lattice Langevin calculations are given for a toy model'' with a scalar field interacting with an exponential potential where one can obtain exact analytic solutions of the Fokker-Planck equation. For single scalar field models that are consistent with current microwave background fluctuations, the fluctuations are Gaussian. However, for scales much larger than our observable Universe, one expects large metric fluctuations that are non-Guassian. This example illuminates non-Gaussian models involving multiple scalar fields which are consistent with current microwave background limits. 21 refs., 3 figs.
Date: November 1, 1990
Creator: Salopek, D.S.
Partner: UNT Libraries Government Documents Department

Uncertainties in forecasting future climate

Description: The increasing atmospheric concentrations of carbon dioxide, methane, chlorofluorocarbons, and other trace gases (collectively, greenhouse gases) pose a three-part challenge: (1) What the changes to atmospheric composition and the climate system will be; (2) What impacts (both detrimental and beneficial) these changes will induce on the biosphere and natural and societal resources; and (3) What the appropriate response, if any, might be when considering the changes themselves, the resulting impacts, and the benefits and other impacts of the activities generating the emissions. This brief summary will address only areas of agreement and areas of uncertainty related to the first challenge.
Date: November 1, 1990
Creator: MacCracken, M.C.
Partner: UNT Libraries Government Documents Department

Zonal statistics in (general circulation model) GCM/GCM/Data intercomparisons

Description: Comparisons of general circulation model (GCM) results with each other and with climate data are routinely made on a variety of spatial scales. In bridging the gap from larger scale behavior (global, hemispheric) to the regional, zonal statistics are commonly used. Here, statistics are developed using values at all longitudinal gridpoints at a specified latitude and these are displayed as a function of latitude. The zonal average is the most routinely used of these statistics, but there are many other statistics available, few of which are ever examined. These provide a rich array of diagnostic measures for intercomparing models with each other and with observational data. Several of these measures are explored here: (1) histograms or boxplots displaying the detailed distributions, (2) rms or average absolute pointwise differences between model and data sets and (3) cross correlations and auto correlations. 5 figs.
Date: November 1, 1990
Creator: Grotch, S.L.
Partner: UNT Libraries Government Documents Department

Edge fluctuations in the MST (Madison Symmetric Torus) reversed field pinch

Description: Edge magnetic and electrostatic fluctuations are measured in the Madison Symmetric Torus (MST) reversed field pinch. At low frequency (<25 kHz), the mode number spectra of magnetic fluctuations agree very well with theoretical prediction for nonlinearly saturated tearing fluctuations resonant in the core. At high frequency (50 kHz to 100 kHz) the magnetic spectra broaden and the modes become resonant in the reversal region. Nonlinear phenomena are under experimental investigation. The low frequency fluctuations phase-lock together to produce a rotating localized disturbance. Bi-spectral analysis in frequency also reveals nonlinear three-wave mode-coupling at low frequency. Electrostatic fluctuations are substantial and do not appear to obey a Boltzmann relation (i.e. e{tilde {phi}}/kT{sub e} > {tilde p}{sub e}/p{sub e} where {tilde {phi}} and {tilde p}{sub e} are the fluctuating potential and pressure, respectively). From measurements of the fluctuating density, temperature, and potential we infer that the electrostatic fluctuation induced transport of particles and energy can be substantial. 13 refs., 11 figs.
Date: October 1, 1990
Creator: Almagri, A.; Assadi, S.; Beckstead, J.; Chartas, G.; Crocker, N.; Den Hartog, D. et al.
Partner: UNT Libraries Government Documents Department

Haze in the Grand Canyon: An evaluation of the Winter Haze Intensive Tracer Experiment

Description: The Grand Canyon is one of the most spectacular natural sights on earth. Approximately 4 million visitors travel to Grand Canyon National Park (GCNP) each year to enjoy its majestic geological formations and intensely colored views. However, visibility in GCNP can be impaired by small increases in concentrations of fine suspended particles that scatter and absorb light; the resulting visibility degradation is perceived as haze. Sulfate particles are a major factor in visibility impairment at Grand Canyon in summer and winter. Many wintertime hazes at GCNP are believed to result from the accumulation of emissions from local sources during conditions of air stagnation, which occur more frequently in winter than in summer. In January and February 1987, the National Park Service (NPS) carried out a large-scale experiment known as the Winter Haze Intensive Tracer Experiment (WHITEX) to investigate the causes of wintertime haze in the region of GCNP and Canyonlands National Park. The overall objective of WHITEX was to assess the feasibility of attributing visibility impairment in specific geographic regions to emissions from a single point source. The experiment called for the injection of a tracer, deuterated methane (CD{sub 4}), into one of the stacks of the Navajo Generating Station (NGS), a major coal-fired power plant located 25 km from the GCNP boundary and 110 km northeast of Grand Canyon Village. A network of field stations was established in the vicinity -- mostly to the northeast of GCNP and NGS -- to measure CD{sub 4} concentrations, atmospheric aerosol and optical properties, and other chemical and physical attributes. 19 refs., 3 figs.
Date: October 1, 1990
Partner: UNT Libraries Government Documents Department

Influence of present and possible future aircraft emissions on the global ozone distribution

Description: This study has used the LLNL two-dimensional model of the global atmosphere in an evaluation of the effects on global ozone concentrations from current subsonic aircraft emissions and from the emissions of possible future high speed civil transports (HSCT). The authors have attempted to include more realistic representations of emissions as a function of altitude and latitude in these scenarios than were included in previous sensitivity analyses. Major findings from this study are: (1) Current aircraft emissions may be having an impact on upper tropospheric ozone, leading to increasing concentrations of ozone in the upper troposphere. (2) A matrix of HSCT scenarios evaluated over a wide range of mean flight altitudes and magnitudes of NO{sub x} emissions confirmed previous analyses showing that ozone destruction becomes larger as the emissions of NO{sub x} increase and as the altitude of injection increases. (3) Model calculations indicate that a major reduction in emissions would allow the stratosphere to recover to unperturbed conditions in about a decade. (4) Sensitivity studies indicate that water vapor emissions have a moderate effect on the change in total ozone, while carbon monoxide emissions had a negligible effect. (5) Injection of NO{sub x} as HNO{sub 3} had a moderate effect on the change in total ozone. (6) The calculated change in ozone for the HSCT scenarios was very sensitive to the background atmosphere, particularly to the levels of stratospheric chlorine and concentrations of carbon dioxide, methane, and nitrous oxide.
Date: October 1, 1990
Creator: Kinnison, D.E. & Wuebles, D.J.
Partner: UNT Libraries Government Documents Department

Modelling of drift wave turbulence with a finite ion temperature gradient

Description: With the use of consistent orderings in {var epsilon} = {rho}{sub s}/a and {delta} = k{sub {perpendicular}}{rho}{sub s} model equations are derived for the drift instabilities from the electrostatic two-fluid equations. The electrical resistivity {eta} included in the system allows the dynamics of both the collisional drift wave instability ({eta} {ne} 0) and the collisionless ion temperature gradient driven instability ({eta} = 0). The model equations used extensively in earlier nonlinear studies are obtained as appropriate limits of the model equations derived in the present work. The effects of sheared velocity flows in the equilibrium plasma and electron temperature fluctuations are also discussed. 14 refs.
Date: October 1, 1990
Creator: Hamaguchi, S. & Horton, W.
Partner: UNT Libraries Government Documents Department

Solar variations and their influence on trends in upper stratospheric ozone and temperature

Description: Over the past decade, knowledge of the magnitude and temporal structure of the variations in the sun's ultraviolet irradiance has increased steadily. A number of theoretical modeling studies have shown that changes in the solar ultraviolet flux during the 11-year solar cycle can have a significant effect on stratospheric ozone concentrations. With the exception of Brasseur et al., who examined a very broad range of solar flux variations, all of these studies assumed much larger changes in the ultraviolet flux than measurements now indicate. These studies either calculated the steady-state effect at solar maximum and solar minimum or assumed sinusoidal variations in the solar flux changes with time. It is now possible to narrow the uncertainty range of the expected effects on upper stratospheric ozone and temperature resulting from the 11-year solar cycle. A more accurate representation of the solar flux changes with time is used in this analysis, as compared to previous published studies. This study also evaluates the relative roles of solar flux variations and increasing concentrations of long-lived trace gases in determining the observed trends in upper stratospheric ozone and temperature. The LLNL two-dimensional chemical-radiative-transport model of the global atmosphere is used to evaluate the combined effects on the stratosphere from changes in solar ultraviolet irradiances and trace gas concentrations over the last several decades. Derived trends in upper stratospheric ozone concentrations and temperature are then compared with available analyses of ground-based and satellite measurements over this time period.
Date: October 1, 1990
Creator: Wuebbles, D.J.; Kinnison, D.E. (Lawrence Livermore National Lab., CA (USA)) & Lean, J.L. (Naval Research Lab., Washington, DC (USA). E.O. Hulburt Center for Space Research)
Partner: UNT Libraries Government Documents Department