Los Angeles Basin Research Articles

Sources, Composition and Absorption Ångström Exponent of Light-absorbing Organic Components in Aerosol Extracts from the Los Angeles Basin

We investigate the sources, chemical composition, and spectral properties of light-absorbing organic aerosol extracts (i.e., brown carbon, or BrC) in the Los Angeles (LA) Basin during the CalNex-2010 field campaign. Light absorption of PM2.5 water-soluble components at 365 nm (Abs365), used as a proxy for water-soluble BrC, was well correlated with water-soluble organic carbon (WSOC) (r(2) = 0.55-0.65), indicating secondary organic aerosol (SOA) formation from anthropogenic emissions was the major source of water-soluble BrC in this region. Normalizing Abs365 to WSOC mass yielded an average solution mass absorption efficiency (MAE365) of 0.71 m(2) g(-1) C. Detailed chemical speciation of filter extracts identified eight nitro-aromatic compounds that were correlated with Abs365. These compounds accounted for ∼4% of the overall water-soluble BrC absorption. Methanol-extracted BrC in LA was approximately 3 and 21 times higher than water-soluble BrC at 365 and 532 nm, respectively, and had a MAE365 of 1.58 m(2) g(-1) C (Abs365 normalized to organic carbon mass). The water-insoluble BrC was strongly correlated with ambient elemental carbon concentration, suggesting similar sources. Absorption Ångström exponent (Å(a)) (fitted between 300 and 600 nm wavelengths) was 3.2 (±1.2) for the PILS water-soluble BrC measurement, compared to 4.8 (±0.5) and 7.6 (±0.5) for methanol- and water-soluble BrC from filter extracts, respectively. These results show that fine particle BrC was prevalent in the LA basin during CalNex, yet many of its properties and potential impacts remain unknown.

Multiyear trends in volatile organic compounds in Los Angeles, California: Five decades of decreasing emissions

Airborne measurements of volatile organic compounds (VOCs) were performed during CalNex 2010 (California Research at the Nexus of Air Quality and Climate Change) in the Los Angeles (LA) basin in May–June 2010 and during ITCT2k2 (Intercontinental Transport and Chemical Transformation) in May 2002. While CO2 enhancements in the basin were similar between the two years, the ΔCO/ΔCO2 ratio had decreased by about a factor of two. The ΔVOC/ΔCO emission ratios stayed relatively constant between the two years. This indicates that, relative to CO2, VOCs in the LA basin also decreased by about a factor of two since 2002. These data are compared with the results from various previous field campaigns dating back as early as 1960 and from the extensive air quality monitoring system in the LA basin going back to 1980. The results show that the mixing ratios of VOCs and CO have decreased by almost two orders of magnitude during the past five decades at an average annual rate of about 7.5%. Exceptions to this trend are the small alkanes ethane and propane, which have decreased slower due to the use and production of natural gas. A comparison with trends in London, UK shows that, due to stricter regulations at the time, VOC mixing ratios in LA decreased earlier than in London, albeit at a slower rate, such that typical mixing ratios in both cities in 2008 were at about the same level.

Black carbon aerosol over the Los Angeles Basin during CalNex

Refractory black carbon (rBC) mass and number concentrations were quantified by a Single Particle Soot Photometer (SP2) in the CalNex 2010 field study on board the Center for Interdisciplinary Remotely‐Piloted Aircraft Studies (CIRPAS) Twin Otter in the Los Angeles (LA) Basin in May, 2010. The mass concentrations of rBC in the LA Basin ranged from 0.002–0.530μg m−3, with an average of 0.172 μg m−3. Lower concentrations were measured in the Basin outflow regions and above the inversion layer. The SP2 afforded a quantification of the mixing state of rBC aerosols through modeling the scattering cross‐section with a core‐and‐shell Mie model to determine coating thickness. The rBC particles above the inversion layer were more thickly coated by a light‐scattering substance than those below, indicating a more aged aerosol in the free troposphere. Near the surface, as the LA plume is advected from west to east with the sea breeze, a coating of scattering material grows on rBC particles, coincident with a clear growth of ammonium nitrate within the LA Basin and the persistence of water‐soluble organic compounds as the plume travels through the outflow regions. Detailed analysis of the rBC mixing state reveals two modes of coated rBC particles; a mode with smaller rBC core diameters (∼90 nm) but thick (>200 nm) coating diameters and a mode with larger rBC cores (∼145 nm) with a thin (<75 nm) coating. The “weekend effect” in the LA Basin results in more thickly coated rBC particles, coinciding with more secondary formation of aerosol.

Gasoline emissions dominate over diesel in formation of secondary organic aerosol mass

Although laboratory experiments have shown that organic compounds in both gasoline fuel and diesel engine exhaust can form secondary organic aerosol (SOA), the fractional contribution from gasoline and diesel exhaust emissions to ambient SOA in urban environments is poorly known. Here we use airborne and ground‐based measurements of organic aerosol (OA) in the Los Angeles (LA) Basin, California made during May and June 2010 to assess the amount of SOA formed from diesel emissions. Diesel emissions in the LA Basin vary between weekdays and weekends, with 54% lower diesel emissions on weekends. Despite this difference in source contributions, in air masses with similar degrees of photochemical processing, formation of OA is the same on weekends and weekdays, within the measurement uncertainties. This result indicates that the contribution from diesel emissions to SOA formation is zero within our uncertainties. Therefore, substantial reductions of SOA mass on local to global scales will be achieved by reducing gasoline vehicle emissions.

Observations of ozone transport from the free troposphere to the Los Angeles basin

Analysis of in situ airborne measurements from the CalNex 2010 field experiment (Research at the Nexus of Air Quality and Climate Change) show that ozone in the boundary layer over Southern California was increased by downward mixing of air from the free troposphere (FT). The chemical composition, origin, and transport of air upwind and over Los Angeles, California, were studied using measurements of carbon monoxide (CO), ozone, reactive nitrogen species, and meteorological parameters from the National Oceanic and Atmospheric Administration WP‐3D aircraft on 18 research flights in California in May and June 2010. On six flights, multiple vertical profiles from 0.2–3.5 km above ground level were conducted throughout the Los Angeles (LA) basin and over the Pacific Ocean. Gas phase compounds measured in 32 vertical profiles are used to characterize air masses in the FT over the LA basin, with the aim of determining the source of increased ozone observed above the planetary boundary layer (PBL). Four primary air mass influences were observed regularly in the FT between approximately 1 and 3.5 km altitude: upper tropospheric air, long‐range transport of emissions, aged regional emissions, and marine air. The first three air mass types accounted for 89% of the FT observations. Ozone averaged 71 ppbv in air influenced by the upper troposphere, 69 ppbv in air containing emissions transported long distances, and 65 ppbv in air with aged regional emissions. Correlations between ozone and CO, and ozone and nitric acid, demonstrate entrainment of ozone from the FT into the LA PBL. Downward transport of ozone‐rich air from the FT into the PBL contributes to the ozone burden at the surface in this region and makes compliance with air quality standards challenging.

Source Mechanism and Rupture Directivity of the 18 May 2009 MW 4.6 Inglewood, California, Earthquake

On 18 May 2009, an M_w 4.6 earthquake occurred beneath Inglewood, California, and was widely felt. Though source mechanism and its location suggest that the Newport–Inglewood fault (NIF) may be involved in generating the earthquake, rupture directivity must be modeled to establish the connection between the fault and the earthquake. We first invert for the event’s source mechanism and depth with the cut-and-paste method in the long-period band (>5 s). Because of the low velocity shallow sediments in the Los Angeles (LA) basin, we use two velocity models in the inversion for stations inside and outside the LA basin. However, little difference is observed in the resolved source mechanism (M_w 4.6, strike 246°/145°, dip 50°/77°, rake 17°/138°) and depth (7 to ~9 km), compared to an inversion using the standard southern Calfornia model. With the resolved source parameters, we calibrate the amplitude anomaly of the short-period (0.5–2 Hz) P waves with amplitude adjustment factors (AAF). These AAFs are used as corrections when retrieving source mechanisms of the smaller aftershocks using short-period P waves alone. Most of the aftershocks show similar source mechanisms as that of the mainshock, providing ideal empirical Green’s functions (EGFs) for studying its rupture process. We use a forward modeling approach to retrieve rupture directivity of the mainshock, consistent with movement on the NIF with rupture toward the southeast. Although we focus on P waves for analyzing rupture directivity, the resolved unilateral pattern is also confirmed with the azimuthal variation of the duration of SH waves observed in the basin. The high rupture velocity near the shear velocity and relatively low stress drop are consistent with the hypothesis of rupture on a mature fault.

Modeling weekday to weekend changes in emissions and ozone in the Los Angeles basin for 1997 and 2010

In this study, we used numerical models to investigate weekday to weekend ozone differences in the Los Angeles (LA) basin in 1997 and 2010. We developed relatively complete descriptions of weekday to weekend emission changes for nitrogen oxides (NOx) with 80% of the weekday NOx emissions receiving a weekend adjustment in 1997 and 67% in 2010. Weekend NOx decreases of 34% on Saturday and 45% on Sunday relative to weekdays for 1997 are predicted to become slightly greater by 2010 and are dominated by NOx decreases for on-road vehicles (especially heavy-duty diesel vehicles) and off-road construction equipment. Weekend anthropogenic reactive organic gas (ROG) decreases for 1997 (12% on Saturday and 16% on Sunday) are smaller than for NOx and become even smaller in 2010. However, there is less certainty in the weekend ROG emission changes because only 47% of the weekday ROG emissions received a weekend adjustment in 1997 and only 21% in 2010. The ozone modeling used multiple representations of the meteorology and chemistry in order to identify results that are consistent across these inputs. Weekend ozone increased in central portions of the basin in response to weekend NOx and ROG decreases for both 1997 and 2010, with both the SAPRC99 and CB4 chemical mechanisms, and with all meteorological data sets. Weekend ozone decreased in other portions of the basin in all models. Comparing 2010 to 1997, weekend ozone increases are smaller and confined to smaller portions of the LA basin near the Pacific coast, whereas weekend ozone decreases are larger and more widespread in 2010. For 2010, all models show lower 8-h ozone on Sunday than weekdays in the Riverside/San Bernardino area. First-order sensitivity analysis (via the decoupled direct method) shows that the weekday/weekend ozone changes are mainly due to the NOx emission changes. Also, the weekday/weekend ozone changes for 2010 are sensitive to the choice of initial and boundary concentrations.

Air quality impacts of the October 2003 Southern California wildfires

In Southern California, dry summers followed by hot and dry westerly wind conditions contribute to the region's autumn fire season. In late October 2003, 13 large Southern California wildfires burned more than 750,000 acres of land, destroyed over 3500 structures, and displaced approximately 100,000 people. The fire episode was declared the deadliest and most devastating in more than a decade, and local media advised individuals to stay indoors to avoid exposure to excessive levels of PM, CO, VOCs, and ozone caused by the wildfires. This study examines the actual impact of these wildfires on air quality in urban Los Angeles (LA) using “opportunistic” data from other air pollution studies being conducted at the time of the fires. Measurements of pollutant gases (CO, NOx, and ozone), particulate matter (PM), particle number (PN) concentrations, and particle size distributions at several sampling locations in the LA basin before, during, and after the fire episode are presented. In general, the wildfires caused the greatest increases in PM10levels (a factor of 3–4) and lesser increases in CO, NO, and PN (a factor of up to 2). NO2levels remained essentially unchanged, and ozone concentrations dropped during the fire episode. Particle size distributions of air sampled downwind of the fires showed number modes at diameters between 100 and 200 nm, significantly larger than that of typical urban air. The particles in this size range were shown to effectively penetrate indoors, raising questions about the effectiveness of staying indoors to avoid exposure to wildfire emissions.

AIR QUALITY IMPACTS OF THE OCTOBER 2003 SOUTHERN CALIFORNIA WILDFIRES

[1] In Southern California, dry summers followed by hot and dry westerly wind conditions contribute to the region’s autumn fire season. In late October 2003, 13 large Southern California wildfires burned more than 750,000 acres of land, destroyed over 3500 structures, and displaced approximately 100,000 people. The fire episode was declared the deadliest and most devastating in more than a decade, and local media advised individuals to stay indoors to avoid exposure to excessive levels of PM, CO, VOCs, and ozone caused by the wildfires. This study examines the actual impact of these wildfires on air quality in urban Los Angeles (LA) using ‘‘opportunistic’’ data from other air pollution studies being conducted at the time of the fires. Measurements of pollutant gases (CO, NOx, and ozone), particulate matter (PM), particle number (PN) concentrations, and particle size distributions at several sampling locations in the LA basin before, during, and after the fire episode are presented. In general, the wildfires caused the greatest increases in PM10 levels (a factor of 3–4) and lesser increases in CO, NO, and PN (a factor of up to 2). NO2 levels remained essentially unchanged, and ozone concentrations dropped during the fire episode. Particle size distributions of air sampled downwind of the fires showed number modes at diameters between 100 and 200 nm, significantly larger than that of typical urban air. The particles in this size range were shown to effectively penetrate indoors, raising questions about the effectiveness of staying indoors to avoid exposure to wildfire emissions.

Holocene to Pliocene tectonic evolution of the region offshore of the Los Angeles urban corridor, southern California

Quaternary tectonism in the coastal belt of the Los Angeles urban corridor is diverse. In this paper we report the results of studies of multibeam bathymetry and a network of seismic reflection profiles that have been aimed at deciphering the diverse tectonism and at evaluating the relevance of published explanations of the region's tectonic history. Rapid uplift, subsidence in basins, folds and thrusts, extensional faulting, and strike‐slip faulting have all been active at one place or another throughout the Quaternary Period. The tectonic strain is reflected in the modern physiography at all scales. Los Angeles (LA) Basin has filled from a deep submarine basin to its present condition with sediment impounded behind a large sill formed behind uplifts near the present shoreline. Newport trough to the south‐southeast of LA Basin also accumulated a large volume of sediment, but remained at midbathyal depths throughout the Period. There is little or no evidence of Quaternary extensional tectonism in either basin although as much as 6 km of subsidence, which mainly occurred by sagging, has been recorded in places since the middle Miocene. The uplifts include folded and thrust faulted terranes in the Palos Verdes Hills and the shelves of Santa Monica and San Pedro Bays. The uplifted areas have been shortened in a southwest‐northeast direction by 10% or slightly more, and some folds are reflected in the bathymetry. Two large adjacent midbathyal basins, Santa Monica and San Pedro, show strong evidence of subsidence and slight west‐northwest extension (10%) during the same time folding was taking place in the uplifts. The tectonic boundaries between uplifts and basins are folded, normal faulted, reverse‐faulted, and strike‐slip faulted depending on location. The rapid Quaternary uplift and subsidence, along with the filling of LA Basin, have produced a reversal in the regional physiography. In the early Pliocene, LA Basin was a submarine deep, Palos Verdes and the shelves comprised a northeast basin slope, and the present offshore basins and Catalina Island formed an emergent or shallowly submerged shelf. Since extensional, compressional, and lateral strains are all locally in evidence, simple notions that this part of southern California underwent a change from Miocene transtension to Quaternary transpression fail to explain our observations.

Ozone distributions over the los angeles basin: Three-dimensional simulations with the smog model

The UCLA Surface Meteorology and Ozone Generation (SMOG) model has been applied to simulate and analyze the distributions of ozone in the Los Angeles basin on 27 and 28 August 1987, during the Southern California Air Quality Study (SCAQS). SMOG is an integrated air pollution modeling system that includes the coupled effects of meteorology, pollutant sources and dispersion, photochemistry and aerosol microphysics, and radiative processes. High surface ozone concentrations are predicted along the slopes of the surrounding mountain barriers and in the eastern basin, as observed. The pattern of surface ozone concentrations is shown to be influenced by the evolution of oxidants within the temperature inversion that typically blankets the Los Angeles basin. In the past, dense layers of ozone have been observed to be embedded within the temperature inversion, but their origin has remained unexplained. The present model simulations reproduce these and other three-dimensional structures in the ozone distribution, as documented by measurements in the basin. The high concentrations of oxidants aloft are explained through a detailed dynamical/chemical mechanism. High mountains surrounding the Los Angeles basin block the dispersion of ozone and other pollutants and generally contain them within the basin. At the same time, vertical circulations associated with the interaction of the sea-breeze and mountain slope winds inject pollutants into the base of the inversion and create high concentrations of ozone, PAN, nitric acid, organic nitrates and a variety of other pollutants, including aerosols. The contrast between ozone concentrations at the surface and in these elevated layers can be enhanced in the evening by NO emissions, which titrate ozone near the surface. The elevated layers act as a reservoir for aged pollutants, which can be mixed downward on subsequent days to enhance surface concentrations. The recirculation of pollutants in the Los Angeles basin is thus reinforced by the presence of these oxidant layers, and may be responsible for the rapid increase in surface ozone concentrations often seen in the morning, particularly in the eastern basin where emissions of primary pollutants are relatively small. The impact on surface ozone concentrations of recirculated photochemically aged air is estimated to be as high as 8 pphmv in the eastern Los Angeles basin. These simulations represent the first quantitative description of the role of pollutants aloft on surface air quality.

Urban seismology—Northridge aftershocks recorded by multi-scale arrays of portable digital seismographs

Abstract We deployed portable digital seismographs in the San Fernando Valley (SFV), the Los Angeles basin (LAB), and surrounding hills to record aftershocks of the 17 January 1994 Northridge California earthquake. The purpose of the deployment was to investigate factors relevant to seismic zonation in urban areas, such as site amplification, sedimentary basin effects, and the variability of ground motion over short baselines. We placed seismographs at 47 sites (not all concurrently) and recorded about 290 earthquakes with magnitudes up to 5.1 at five stations or more. We deployed widely spaced stations for profiles across the San Fernando Valley, as well as five dense arrays (apertures of 200 to 500 m) in areas of high damage, such as the collapsed Interstate 10 overpass, Sherman Oaks, and the collapsed parking garage at CalState Northridge. Aftershock data analysis indicates a correlation of site amplification with mainshock damage. We found several cases where the site amplification depended on the azimuth of the aftershock, possibly indicating focusing from basin structures. For the parking garage array, we found large ground-motion variabilities (a factor of 2) over 200-m distances for sites on the same mapped soil unit. Array analysis of the aftershock seismograms demonstrates that sizable arrivals after the direct S waves consist of surface waves traveling from the same azimuth as that of the epicenter. These surface waves increase the duration of motions and can have frequencies as high as about 4 Hz. For the events studied here, we do not observe large arrivals reflected from the southern edge of the San Fernando Valley.

A numerical analysis of los angeles basin pollution transport to the grand canyon under stably stratified, southwest flow conditions

This paper presents a numerical investigation of air pollutant transport from the Los Angeles Basin to Grand Canyon National Park (GCNP) under the stably stratified wintertime, synoptic high-pressure conditions that existed during 10–13 February 1987. The Colorado State University Regional Atmospheric Modeling System (CSU-RAMS) is used to develop fields of different atmospheric variables for 54 simulated hours. These fields are applied in a Lagrangian particle dispersion model (LPDM) to simulate the advection of pollutant particles for this period. It is found that under the generally southwest flow conditions presented, particles released from the Los Angeles Basin will impact the Grand Canyon but only in small amounts. By comparing a flat to complex terrain simulation, the importance of the terrain features between Los Angeles and GCNP to the dispersion of Los Angeles Basin pollutants is made obvious. Mountain barriers and undulating land reduce what could otherwise be a very serious pollutant impact on GCNP. Based on these results the conclusion is made that despite southwest average flow aloft during the Winter Haze Intensive Tracer EXperiment (WHITEX) period of 10–13 February 1987, Los Angeles Basin pollution did not contribute significantly to the observed visibility reduction in the Grand Canyon during that time period.

Investigation of organic aerosol sampling artifacts in the los angeles basin

Filter collection of particulate organic carbon is complicated by adsorption and volatilization sampling artifacts which inhibit attempts to accurately assess aerosol concentrations. Insight into the adsorption artifact can be gained by considering that adsorption on sampling filters is conceptually similar to gas-particle partitioning with the filter acting as a model aerosol. We found that significant adsorption of gas-phase organic compounds occurs on quartz fiber filters, and the presence of typical loadings of particulate material on the sampling filter does not significantly affect the magnitude of the adsorption artifact. Also placing a Teflon filter upstream of a pair of quartz fiber filters has no effect on total organic carbon loadings on the final quartz fiber filter, but adsorbed organic carbon loadings are much higher on quartz fiber filters behind Teflon filters than on quartz fiber filters behind quartz fiber filters. Organic carbon sampled from the atmosphere is unlikely to attain equilibrium between that in the gas phase and that adsorbed on the quartz fiber sampling filter. As a result, a quartz fiber filter behind a quartz fiber filter is exposed to a lower gas-phase concentration than a quartz fiber filter behind a Teflon filter. This explains the difference between Teflon-quartz and quartz-quartz backup filters and suggests that Teflon-quartz backup filters provide a better estimate of adsorbed vapor on quartz fiber front filters than do quartz-quartz backup filters. Under typical sampling conditions adsorption is the dominant artifact in the sampling of particulate organic carbon, and longer sampling periods reduce the percentage of collected material that is adsorbed vapor.

PM10 and ozone control strategy to improve visibility in the los angeles basin☆

Abstract The greater Los Angeles metropolitan area is in violation of the United States Environmental Protection Agency (USEPA) ambient standards for both ozone and PM 10 . Accompanying these violations are hazy summer conditions, with current annual median visibility in the inland portions of Los Angeles running about 13 km, and visibilities decreasing to about 3 km on the 90th percentile days (worst days). The USEPA has given the local air pollution control agency until 2010 to bring the area into compliance with these standards. Because of continued population growth, accompanying light industry, dependence on private motor vehicles, and adverse natural meteorological conditions, emission reductions costing billions of dollars will be needed between now and 2010. The combination of emission reductions which will result in the fastest ozone and PM 10 cleanup at the lowest cost are presented. Substantial emission reductions in NO x , reactive hydrocarbons, SO x , ammonia, soot and fugitive dust will result in visibility improvements in the Los Angeles area. However, enactment of this comprehensive control strategy will only improve the annual median visibility to about 20 km and the 90th percentile days to 6.5 km. Significant changes in fine mass will result in relatively small changes in perceived visibility since the human eye is unable to differentiate visual range changes even as large as 40% in an urban landscape typical of Los Angeles.

CO2 Flooding: Its Time Has Come

Distinguished Author Series articles are general, descriptiverepresentations that summarize the state of the art in an area of technology bydescribing recent developments for readers who are not specialists in thetopics discussed. Written by individuals recognized as experts in the area, these articles provide key references to more definitive work and presentspecific details only to illustrate the technology. Purpose: to informthe general readership of recent advances in various areas of petroleumengineering. Introduction Carbon dioxide is one of the most plentiful and useful compounds found onand around this planet. It is not surprising that the idea of using CO2 toremove oil from underground reservoirs originated early in the history of oilproduction. In the period just following World War II, significant progress wasmade in the development of CO2 oil-recovery processes. In the 1950's, Whortonet al., Saxon et processes. In the 1950's, Whorton et al., Saxon et al., Beesonand Ortloff, Holm, and Martin published patents and papers on the subject thathave published patents and papers on the subject that have laid the foundationfor the oil-recovery processes as they exist today. Most aspects of CO2flooding, including oil swelling, viscosity reduction, miscibility effects, solution gas drive, and reaction with reservoir rock, were identified duringthis laboratory investigative period. Advances in CO2 flooding technologyduring the 1960's included:definition of the amount of CO2 required foroil recovery and information on the effect of reservoir oil viscosity, reservoir rock type and rock heterogeneity, and phase relationships;development of the use of CO2 as a well stimulant additive in fracturing andacidizing; andfield tests of CO2 flooding. The first successful field testof CO2 with waterflooding in the Mead Strawn field confirmed that more oil wasproduced by a CO2 slug followed by waterflooding than by waterflooding alone, and that severe CO2 gravity override and channeling do not necessarily occur inthe reservoir. Continued research and field applications in the 1970's addedconsiderably to our knowledge of CO2 displacement mechanisms, phase behavior, mobility control, CO2 availability, and practical transporting, handling, andoperating problems associated with the process. Five field applications andtests-SACROC, North Crossett, Two Freds, Little Creek, and Lick Creek Meakin -provided more information on the design, operation, and economics of CO2flooding projects. Several U.S. DOE, Natl. Petroleum Council, Federal EnergyAdmin., and private investigations identified CO2 sources and supplies, separation processes, and transportation facilities. These 25 years of effortare now beginning to show results. Current field applications are continuingand expanding. A 1982 survey revealed a 65% increase in the number of CO2projects over 1980. Four large pipelines have been started to bring CO2 fromdistant pipelines have been started to bring CO2 from distant (200 to 400miles) sources. Colorado and New Mexico gas fields will supply CO2 for miscibleflooding in the Wasson and other fields in west Texas. Two other pipelines willserve the Purdy Springer and East pipelines will serve the Purdy Springer andEast Velma fields in Oklahoma, and the Little Creek and West Mallaleiv fieldsin Mississippi. CO2 available from refineries and fertilizer plants in the LosAngeles basin has been targeted for immiscible flooding of local heavy-oilreservoirs. Studies have been made of CO2 pipelines to bring additional CO2from Utah and New Mexico to the basin. Although the economic recession andworldwide oil glut have slowed its progress, CO2 flooding's time has come.progress, CO2 flooding's time has come. JPT P. 2739

Observations and estimation of long‐period strong ground motion in the los angeles basin

AbstractWhile the accurate estimation of ground‐motion amplitudes across the entire frequency band of engineering interest is not possible at the present time, the excitation and propagation of long‐period strong‐ground motion can be understood with existing seismological methodology. In the Los Angeles Basin, the long‐period strong ground motion excited by the San Fernando earthquake is dominated by the presence of surface waves, whose gross amplitude and frequency content are easily attributable to physical properties of the earthquake source and source‐station propagation paths. Observed measures of the long‐period strong ground motion of the Kern County earthquake relative to the San Fernando earthquake at two sites in the Los Angeles Basin which recorded both shocks can be predicted with considerable accuracy by a simple earthquake source model. This source model is extrapolated to represent the maximum credible earthquake likely to affect the Los Angeles area, taken to be a repeat of the Fort Tejon (1857) earthquake along the San Andreas fault. The measures of long‐period strong ground motion in the Los Angeles Basin estimated for it agree well with the comparable measures of Earthquake A‐2, intended to represent the same situation. For the purpose of aseismic design of long‐period structures, Earthquake A‐2 is a reasonable, if not all inclusive, estimate of the long‐period strong ground motion in the Los Angeles Basin generated by a magnitude 8+ earthquake along the San Andreas fault north and east of Los Angeles.

Influence of air parcel trajectories on aerosol variability in the los angeles basin, a case study for 20 September 1972

Through use of a documented interpolation scheme air parcel trajectories reaching the University of Minnesota Particle Technology Laboratory's mobile van on 20 September 1972 have been estimated. The close similarity of all trajectories during the early morning confirms the hypothesis of Whitby et al. (1975), that observed aerosol changes during early morning were not due to changes in the general source region of the sampled air parcels. Trajectory analyses for late morning and afternoon indicate the urban aerosol cloud boundary passed the laboratory shortly after 13:00h PST, not with the sea-breeze at 11:00h PST. Thus, 1300 marks the initial influx of air which had been over the open sea for a relatively long period. Examination of the aerosol measurements shows that some of their variability can be ascribed to the later air mass change.

Establishment of a 450-mc vehicular radio system in the los angeles basin

In order to supply additional mobile-radio-telephone service to the public in the greater Los Angeles area, The Pacific Telephone and Telegraph Company applied for four 450-mc (megacycle) radio channels in June 1956. At that time there were only six channels available for the domestic public mobile-telephone service (MTS) in the 450-460-mc common-carrier radio-frequency (r-f) band.

Completion Practices Related to Well Productivity

Several new procedures for completing oil wells have been developed inrecent years. Each method when used where properly applicable promises to be adefinite aid to operators in lowering development or operating costs, or indeveloping the full potentialities of the oil well. Multiple-zone completionsare now frequently used, in contrast to the older practice of setting a solidwater string over each zone to be produced. Gravel packing in unconsolidatedformations often prevents sand troubles formerly experienced where aconventional perforated liner was used. Light-weight bentonitic clay muds andoil-base drilling fluids are definite steps toward eliminating mudding damage, which occurs when heavy rotary mud is used. Since in each case the new procedure developed is an alternate of olderconventional methods, a problem of selection is presented. The purpose of thispaper is to suggest methods of arriving at these choices and to presentpractical observations that may be of aid in their application. Introduction Discovery of deep and prolific oil-producing zones in the San Joaquin Valleyof California during the years 1936, 1937 and 1938 directed attention to meansof improving rates of penetration in drilling. In these years rapid advanceswere made in hole-making technique, and as a result the investment required fordeep development projects was substantially reduced. Improvements introducedduring this period included:larger drilling machinery, with fasterhoisting speeds, higher rotary speeds, and larger circulation volumesbetter mud controlincreased use of alloy steels. This increasedefficiency of operation has been maintained but further improvement in deepdrilling practice has been less marked in the years 1939, 1940 and 1941. Thediscovery and intensive development of the Wilmington field, in the Los AngelesBasin, which reached its peak in 1938, was influential in shifting the emphasisfrom hole making to completion procedure. Since 1938, California operators havedevoted an increased amount of study to programs for drilling in and completingwells. This new emphasis on completion procedure has, led to the development oftechniques that represent the first successful departures from conventionalmethods to be introduced in many years. T.P. 1465