Characterization of Asian Dust during ACE-Asia   总被引：4，自引：1，他引：3  

R. Arimoto  Y.J. Kim  Y.P. Kim  P.K. Quinn  T.S. Bates  T.L. Anderson  S. Gong  I. Uno  M. Chin  B.J. Huebert  A.D. Clarke  Y. Shinozuka  R.J. Weber  J.R. Anderson  S.A. Guazzotti  R.C. Sullivan  D.A. Sodeman  K.A. Prather  I.N. Sokolik 《Global and Planetary Change》2006,52(1-4):23

ACE-Asia was a multi-national collaboration organized to investigate and understand the chemistry, radiative properties, and climatic effects of mineral dust and other aerosol particles in the East Asia/Northwest Pacific region. Studies conducted at the Gosan and Zhenbeitai surface supersites show striking variations in aerosol concentrations and properties that were affected by the occurrence and origins of the Asian dust storms, air mass pathways, and mixing during the transport. Investigations conducted on the R/V Ronald H. Brown (RHB) showed that dust had a pervasive influence on the chemical composition, size distribution, and optical properties of the aerosol. Analyses using an aerosol time-of-flight mass spectrometer on the RHB showed that most of the coarse-particle nitrate and sulfate in post-frontal air was associated with dust, and more remarkably, that competitive or exclusionary processes evidently are involved in the uptake or production of these substances. Studies conducted onboard the NCAR C-130 aircraft showed that coarse-mode dust was less absorbing and less hygroscopic than pollution aerosol and that there was little correlation in light scattering and absorption by the sub- vs. super-micrometer aerosol. Below 2 km, dust was commonly mixed with pollutants, and this had a stronger influence on the optical properties of the submicrometer particles than the coarse-mode dust; at higher altitudes, the dust was less affected by pollution. Single particle analyses of C-130 samples showed that the mixing of black carbon (BC) with dust was common, but only certain types of BC particles were aggregated. Models were used in the planning, execution and interpretative phases of ACE-Asia; and summaries of modeling results are presented to illustrate the progress being made in identifying new dust sources; in depicting the time-varying, three-dimensional structure of dust plumes; and in quantifying the production, transport, and deposition of Asian dust.  相似文献   

Turbulent Statistics of Neutrally Stratified Flow Within and Above a Sparse Forest from Large-Eddy Simulation and Field Observations   总被引：17，自引：13，他引：4  

Hong-Bing Su  Roger H. Shaw  Kyaw Tha Paw  Chin-Hoh Moeng  Peter P. Sullivan 《Boundary-Layer Meteorology》1998,88(3):363-397

Turbulent statistics of neutrally stratified shear-driven flow within and above a sparse forest canopy are presented from a large-eddy simulation (LES) and compared with those from observations within and above a deciduous forest with similar height and foliage density. First- and second-order moments from the LES agree with observations quite well. Third-order moments from the LES have the same sign and similar vertical patterns as those from the observations, but the LES yields smaller magnitudes of such higher-order moments. Turbulent spectra and cospectra from the LES agree well with observations above the forest. However, at the highest frequencies, the LES spectra have steeper slopes than observations. Quadrant and conditional analyses of the LES resolved-scale flow fields also agree with observations. For example, both LES and observation find that sweeps are more important than ejections for the transport of momentum within the forest, while inward and outward interaction contributions are both small, except near the forest floor. The intermittency of the transport of momentum and scalar increases with depth into the forest. Finally, ramp structures in the time series of a passive scalar at multiple levels within and above the forest show similar features to those measured from field towers. Two-dimensional (height-time cross-section) contours of the passive scalar and wind vectors show sweeps and ejections, and the characteristics of the static pressure perturbation near the ground resemble those deduced from field tower-based measurements. In spite of the limited grid resolution (2 m × 2 m × 2 m) and domain size (192 m × 192 m × 60 m) used in this LES, we demonstrate that the LES is capable of resolving the most important characteristics of the turbulent flow within and above a forest canopy.  相似文献   

An evaluation of trace element release associated with acid mine drainage     

Patrick J. Sullivan  Jennifer L. Yelton 《Environmental Geology》1988,12(3):181-186

The determination of trace element release from geologic materials, such as oil shale and coal overburden, is important for proper solid waste management planning. The objective of this study was to determine a correlation between trace element residency and concentration to trace element release using the following methods: (1) sequential selective dissolution for determining trace element residencies, (2) toxicity characteristic leaching procedure (TCLP), and (3) humidity cell weathering study simulating maximum trace element release. Two eastern oil shales were used, a New albany shale that contains 4.6 percent pyrite, and a Chattanooga shale that contains 1.5 percent pyrite. Each shale was analyzed for elemental concentrations by soluble, adsorbed, organic, carbonate, and sulfide phases. All leachates were analyzed to determine total trace element concentrations. The results of the selective dissolution studies show that each trace element has a unique distribution between the various phases. Thus, it is possible to predict trace element release based on trace element residency. The TCLP results show that this method is suitable for assessing soluble trace element release but does not realistically assess potential hazards. The results of the humidity cell studies do demonstrate a more reasonable method for predicting trace element release and potential water quality hazards. The humidity cell methods, however, require months to obtain the required data with a large number of analytical measurements. When the selective dissolution data are compared to the trace element concentrations in the TCLP and humidity cell leachates, it is shown that leachate concentrations are predicted by the selective dissolution data. Therefore, selective dissolution may represent a rapid method to assess trace element release associated with acid mine drainage.  相似文献   

The structure and magnitude of concentration fluctuations     

P. C. Chatwin  Paul J. Sullivan 《Boundary-Layer Meteorology》1993,62(1-4):269-280

This paper is concerned with the science of turbulent diffusion and not, except incidentally, with its numerous practical applications. It discusses some recent research, particularly that by the authors and their collaborators. Among the topics considered are (i) the intermittency factor, (ii) the relationship between the mean of the concentration and its variance, and (iii) the interpretation of data. The principal aim of the paper is to draw attention to some outstanding basic questions which would seem promising targets for future research. Without progress on these questions (and others), regulatory modesl of air quality will continue-inevitably-to be unreliable and hardly worth using.  相似文献   

A grid nesting method for large-eddy simulation of planetary boundary-layer flows   总被引：3，自引：1，他引：3  

Peter P. Sullivan  James C. McWilliams  Chin-Hoh Moeng 《Boundary-Layer Meteorology》1996,80(1-2):167-202

A method for performing nested grid calculations with a large-eddy simulation code is described. A common numerical method is used for all meshes, and the grid architecture consists of a single outer or coarse grid, and nested or fine grids, which overlap in some common region. Inter-grid communication matches the velocity, pressure and potential temperature fields in the overlap region. Resolved and sub-grid scale (SGS) turbulent fluxes and kinetic energy on the fine grid are averaged to the coarse grid using a conservation rule equivalent to Germano's identity used to develop dynamic SGS models.Simulations of a slightly convective, strong shear planetary boundary layer were carried out with varying surface-layer resolutions. Grid refinements in the (x, y, z) directions of up to (5, 5, 2) times were employed. Two-way interaction solutions on the coarse and fine meshes are successfully matched in the overlap region on an instantaneous basis, and the turbulent motions on the fine grid blend smoothly into the coarse grid across the grid interface. With surface-layer grid nesting, significant increases in resolved eddy fluxes and variances are found. The energy-scale content of the vertical velocity, and hence vertical turbulent fluxes, appear to be most influenced by increased grid resolution. Vertical velocity spectra show that the dominant scale shifts towards higher wavenumbers (smaller scales) and the magnitude of the peak energy is increased by more than a factor of 3 with finer resolution. Outside of the nested region the average heat and momentum fluxes and spectra are slightly influenced by the fine resolution in the surface layer. From these results we conclude that fine resolution is required to resolve the details of the turbulent motions in the surface layer. At the same time, however, increased resolution in the surface layer does not appreciably alter the ensemble statistics of the resolved and SGS motions outside of the nested region.  相似文献   

Trace element distribution and oil yield data from the parachute creek member of the green river formation,colorado     

Patrick J. Sullivan  Robert C. Donovan 《Environmental Geology》1987,10(1):21-31

The determination of trace element concentrations in oil shale before mining and retorting is required for proper solid-waste management planning. Using routine Fischer assay oil yield data collected during resource characterization as indicators of potential trace element concentrations could lead to a standard method of identifying strata containing high trace element levels. In order to determine a correlation between trace element concentrations and oil yield, shale samples were selected from four statigraphic zones of the Parachute Creek Member of the Green River Formation for analysis. All samples were analyzed for total elemental concentrations, mineralogy, and Fischer assay oil yield. The results of these analyses demonstrated that the Mahogany zone shales contain significantly greater trace element concentrations (antimony, arsenic, cadmium, chromium, copper, lead, lithium, mercury, molybdenum, nickel, selenium, silver, and vanadium) than the other three shale zones. These high trace element concentrations have been identified within well-defined interbedded tuff deposits in the Mahogany zone. In addition, all trace elements evaluated, except boron, show either increasing or decreasing concentrations as oil yield increases within all oil shale zones. With an increased number of analyses of existing oil shale cores, oil yield data will be correlated to specific stratigraphic units containing high trace element concentrations.  相似文献   

Erratum to: Impacts of rising air temperatures and emissions mitigation on electricity demand and supply in the United States: a multi-model comparison     

James McFarland  Yuyu Zhou  Leon Clarke  Patrick Sullivan  Jesse Colman  Wendy S. Jaglom  Michelle Colley  Pralit Patel  Jiyon Eom  Son H. Kim  G. Page Kyle  Peter Schultz  Boddu Venkatesh  Juanita Haydel  Charlotte Mack  Jared Creason 《Climatic change》2015,132(4):739-739

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Preparedness and Warning Systems for Populations with Special Needs: Ensuring Everyone Gets the Message (and Knows What To Do)     

Helen T. Sullivan  Markku T. Häkkinen 《Geotechnical and Geological Engineering》2011,29(3):225-236

The recent South Asian Tsunami has brought world-wide awareness to the effects of major disasters upon all segments of society. Vulnerable populations such as the disabled, children, or the elderly are at particular risk in a disaster and it is vital to consider their special needs in the design of disaster preparedness and warning systems. Additionally, tourists, recent immigrants, and refugees face challenges when confronted with disaster in unfamiliar locations, linguistically isolated, and in need of assimilating lifesaving information and guidance quickly when under stress. Attention to the requirements for persons with disabilities may also benefit the greater general population which can find itself situationally disabled. Information and Communications Technology based upon accessible design principles is part of the solution. Understanding of psychology, ergonomics, and information design is vital, as are the unique perceptual, cognitive, physical, and linguistic challenges that can influence the efficacy of the message. These issues are among those addressed in an ongoing project in Urakawa, Japan, which is developing a disaster preparedness information system that meets the needs of persons with disabilities.  相似文献   

Displacement-based design of steel moment resisting frames with partially-restrained beam-to-column joints     

R. Roldán  T. J. Sullivan  G. Della Corte 《Bulletin of Earthquake Engineering》2016,14(4):1017-1046

This article presents a method for the direct displacement-based design of steel moment resisting frames, with specific consideration of beam-to-column joint characteristics. The method can be used for steel frames having any type of beam-to-column joints, from rigid and full-strength to semi-rigid and partial-strength. The plastic rotation capacity of the joints is explicitly taken into account within the performance criteria for the design. To assess the accuracy of the method in controlling performance, case study structures were first designed and subsequently analysed using non-linear dynamic analysis with a set of real accelerograms. For all cases, the mean of peak inter-storey drift demands and the mean of peak plastic rotation demands on joints were controlled in accordance with the limits set during design. The results obtained demonstrate that the proposed method is appropriate for the performance-based seismic design of steel moment resisting frames with different joint typologies.  相似文献   

The Phoenix Deep Survey: the star formation rates and the stellar masses of extremely red objects     

A. Georgakakis  A. M. Hopkins  J. Afonso  M. Sullivan  B. Mobasher  L. E. Cram 《Monthly notices of the Royal Astronomical Society》2006,367(1):331-338

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